CARDIOVASCULAR SYSTEMCARDIOVASCULAR SYSTEMByBy

Yasmeen RahimYasmeen Rahim

OBJECTIVESOBJECTIVES

By the end of this presentation, learners will be By the end of this presentation, learners will be able to:able to:

Review anatomy and physiology of heart.Review anatomy and physiology of heart.

Define ECG and list indications for ECG.Define ECG and list indications for ECG.

Identify different kinds of arrhythmias.Identify different kinds of arrhythmias.

Discuss different kinds of heart blocks.Discuss different kinds of heart blocks.

Describe the nursing care for patient in blocks.Describe the nursing care for patient in blocks.

Discuss types and care for client with Discuss types and care for client with temporary and permanent pacemakers.temporary and permanent pacemakers.

HEARTHEART

Heart is a hollow muscular organ, located Heart is a hollow muscular organ, located in mediastinum.in mediastinum.

It lies with the lungs on the either side and It lies with the lungs on the either side and the diaphragm below.the diaphragm below.

The base of heart lies parallel with the The base of heart lies parallel with the edge of sternum.edge of sternum.

The apex of the heart is at the The apex of the heart is at the midclavicular line at the 5midclavicular line at the 5 thth intercoastal intercoastal space.space.

CONT.CONT.

Heart size varies according to person’s Heart size varies according to person’s body size (closed fist).body size (closed fist).

The organ is roughly about 12 cm long The organ is roughly about 12 cm long and 9 cm wide.and 9 cm wide.

The heart is enclosed by a thick double The heart is enclosed by a thick double wall sac called pericardium.wall sac called pericardium.

Pericardium is composed of three layers;Pericardium is composed of three layers;

epicardium, myocardium and endocardium.epicardium, myocardium and endocardium.

LAYERS OF HEARTLAYERS OF HEART

EPICARDIUM: EPICARDIUM: the outermost layer of the outermost layer of heart, composed of a serous membrane.heart, composed of a serous membrane.

MYOCARDIUM: MYOCARDIUM: it makes up the largest it makes up the largest portion of the heart’s wall. This layer of portion of the heart’s wall. This layer of muscle tissue contracts with each beat.muscle tissue contracts with each beat.

ENDOCARDIUM: ENDOCARDIUM: the innermost layer of the innermost layer of the heart wall composed of endothelial the heart wall composed of endothelial cells that lines the heart chamber and cells that lines the heart chamber and valves.valves.

CHAMBERS OF HEARTCHAMBERS OF HEART

The heart is divided into four chambers:The heart is divided into four chambers:

Right atriumRight atrium

Right ventricleRight ventricle

Left atriumLeft atrium

Right atriumRight atrium

VALVESVALVES

Heart has four valves:Heart has four valves:– Tricuspid valve Tricuspid valve – Bicuspid valveBicuspid valve– Pulmonic valvePulmonic valve– Aortic valve Aortic valve

Valves close and open in response to Valves close and open in response to change in pressure within the chamber.change in pressure within the chamber.

They serve as one way door in order to They serve as one way door in order to prevent regurgitation of blood from one prevent regurgitation of blood from one chamber to another.chamber to another.

PULMONARY CIRCULATIONPULMONARY CIRCULATION

CORONARY CIRCULATION

CORONARY CIRCULATIONCORONARY CIRCULATION

Cont…Cont…

Coronary arteries originate from aorta, Coronary arteries originate from aorta, immediately above aortic valveimmediately above aortic valve

2 main branches: Right and Left coronary 2 main branches: Right and Left coronary arteryartery

LCA has 2 major branches: Left anterior LCA has 2 major branches: Left anterior descending (LAD) and Left circumflex descending (LAD) and Left circumflex artery (LCA)artery (LCA)

CARDIAC CONDUCTIONCARDIAC CONDUCTION

Sinoatrial (SA) node – Fires at 60–100 Sinoatrial (SA) node – Fires at 60–100 beats/minutebeats/minute

Intranodal pathwayIntranodal pathway

Atrioventricular (AV) node – Fires at 40-60 Atrioventricular (AV) node – Fires at 40-60 beats/minutebeats/minute

Atrioventricular bundle of HisAtrioventricular bundle of His– Ventricular tissue fires at 20-40 beats/minute Ventricular tissue fires at 20-40 beats/minute

and can occur at this point and downand can occur at this point and down

Right and left bundle branches Right and left bundle branches

Purkinje fibersPurkinje fibers

ELECTROCARDIOGRAMELECTROCARDIOGRAMConduction Conduction of an action of an action potential potential through the through the heart can heart can be shown be shown by an by an electrocardielectrocardiogram ogram (ECG).(ECG).

CARDIAC CYCLECARDIAC CYCLE

SystoleSystole = = period of period of ventricular ventricular contraction.contraction.

DiastoleDiastole = = period of period of ventricular ventricular relaxation.relaxation.

CARDIAC CYCLECARDIAC CYCLE

Contraction of the myocardium generates Contraction of the myocardium generates pressure changes which result in the pressure changes which result in the orderly movement of blood. orderly movement of blood.

Blood flows from an area of Blood flows from an area of high high pressurepressure to an area of to an area of low pressurelow pressure, , unless flow is blocked by a valve. unless flow is blocked by a valve.

Events on the right and left sides of the Events on the right and left sides of the heart are the same, but pressures are heart are the same, but pressures are lower on the right side of the heart. lower on the right side of the heart.

ATRIAL SYSTOLEATRIAL SYSTOLE

The heart is full of blood and the ventricles The heart is full of blood and the ventricles are relaxed and are about ¾ full.are relaxed and are about ¾ full.

Both the atria contract and 30% blood Both the atria contract and 30% blood passes down to the ventricles (atrial kick)passes down to the ventricles (atrial kick)

The atrio-ventricular valves open due to The atrio-ventricular valves open due to blood pressure.blood pressure.

70% of the blood flows 70% of the blood flows passively passively down to down to the ventricles as a result of pressure the ventricles as a result of pressure difference b/w atrias and ventriclesdifference b/w atrias and ventricles

VENTRICULAR SYSTOLEVENTRICULAR SYSTOLEThe first part of ventricular systole is known as The first part of ventricular systole is known as isovolumetric contraction period.isovolumetric contraction period.

It begins with the closure of AV valve (lub sound).It begins with the closure of AV valve (lub sound).

In additional 0.02 to 0.03 sec semilunar valves In additional 0.02 to 0.03 sec semilunar valves remain closed.remain closed.

During this period volume remain same but the During this period volume remain same but the ventricles are contracting (ventricles are contracting (↑↑pressure)pressure)

The atrias are relax.The atrias are relax.

IVC is an interval between the closing of the AV IVC is an interval between the closing of the AV valves and the opening of the semilunar valves valves and the opening of the semilunar valves (aortic and pulmonary valves).(aortic and pulmonary valves).

VENTRICULAR SYSTOLEVENTRICULAR SYSTOLE

Second phase of ventricular systole is Second phase of ventricular systole is known as ejection phase.known as ejection phase.

The increase pressure of blood in the The increase pressure of blood in the ventricles opens the semi-lunar valves.ventricles opens the semi-lunar valves.

Blood passes into the aorta and Blood passes into the aorta and pulmonary arteries due to pressure pulmonary arteries due to pressure difference.difference.

VENTRICULAR DIASTOLEVENTRICULAR DIASTOLEThis phase is known as isovolumetric This phase is known as isovolumetric relaxation phase.relaxation phase.

Pressure in the ventricles falls below that in Pressure in the ventricles falls below that in the arteriesthe arteries

Blood under high pressure in the arteries Blood under high pressure in the arteries causes the semi lunar valves to shut. causes the semi lunar valves to shut.

This produces the second heart sound, ‘dub’.This produces the second heart sound, ‘dub’.

During diastole, all the muscle in the heart During diastole, all the muscle in the heart relaxes for 0.03 to 0.06 secs.relaxes for 0.03 to 0.06 secs.

VENTRICULAR DIASTOLEVENTRICULAR DIASTOLE

This phase is marked by ventricular filling.This phase is marked by ventricular filling.

When pressure in ventricles become less When pressure in ventricles become less than atria, AV valves open and blood flows than atria, AV valves open and blood flows into ventricles.into ventricles.

This is known as rapid filling period.This is known as rapid filling period.

Ventricular blood volume at the end of Ventricular blood volume at the end of diastole is 120 ml (EDV) and ESV is 50 diastole is 120 ml (EDV) and ESV is 50 ml.ml.

Atria contract in the later half of this Atria contract in the later half of this phase.phase.

FUNCTIONARY TERMS FUNCTIONARY TERMS

Automaticity:Automaticity: the ability of specialized cells in the ability of specialized cells in the heart known as pacemaker cells to the heart known as pacemaker cells to spontaneously generate an action potential, spontaneously generate an action potential, thus causing depolarization.thus causing depolarization.

Conductivity:Conductivity: the ability of cardiac cells to the ability of cardiac cells to conduct action potentials, thus transmitting the conduct action potentials, thus transmitting the electrical signal from one cell to another.electrical signal from one cell to another.

Contractility:Contractility: the ability of cardiac muscle to the ability of cardiac muscle to shorten in response to depolarization.shorten in response to depolarization.

Cont..Cont..

Excitability:Excitability: the ability of cardiac tissue to the ability of cardiac tissue to respond to a stimulus and generate an action respond to a stimulus and generate an action potential.potential.

Rhythmicity:Rhythmicity: the ability of cardiac cells to the ability of cardiac cells to spontaneously generate an action potential spontaneously generate an action potential at a regular rate.at a regular rate.

STROKE VOLUME STROKE VOLUME is the amount of blood is the amount of blood ejected per ventricular contraction. ejected per ventricular contraction.

Normal value is 60 – 100 ml / beat.Normal value is 60 – 100 ml / beat.

Stroke volume = EDV - ESVStroke volume = EDV - ESV

Cont..Cont..

CARDIAC OUTPUTCARDIAC OUTPUT is the amount of blood is the amount of blood ejected from left ventricle (in liters) in each ejected from left ventricle (in liters) in each minute.minute.

Cardiac output = Heart rate Cardiac output = Heart rate ×× Stroke volume.Stroke volume.

Normal CO for an adult ranges from 4 – 8 Normal CO for an adult ranges from 4 – 8 L/minL/minCARDIAC INDEX CARDIAC INDEX is cardiac output per square is cardiac output per square meter of body surface area. meter of body surface area. Ranges from 2.8 – 4.2 L/minute/mRanges from 2.8 – 4.2 L/minute/m2. 2. CI = CO / body surface areaCI = CO / body surface area

HEART RATEHEART RATE

Heart rate Heart rate determines determines the frequency the frequency with which the with which the blood is blood is ejected from ejected from heart.heart.Therefore if Therefore if HR increases HR increases then CO will then CO will increase and increase and vice versa.vice versa.

REGULATION OF HRREGULATION OF HR

Heart rate is under autonomic and adrenal Heart rate is under autonomic and adrenal catecholamine influence.catecholamine influence.

Sympathetic NS (norepinephrine increases Sympathetic NS (norepinephrine increases depolarization rate)depolarization rate)

Parasympathetic NS (acetylcholine decrease Parasympathetic NS (acetylcholine decrease rate of depolarization)rate of depolarization)

Adrenal medulla secretes epinephrine and Adrenal medulla secretes epinephrine and norepinephrine (act on heart same way as norepinephrine (act on heart same way as SNS)SNS)

REGULATION OF STROKE REGULATION OF STROKE VOLUMEVOLUME

Factors involved in regulation of stroke Factors involved in regulation of stroke volume are:volume are:

PreloadPreload

AfterloadAfterload

ContractilityContractility

PRELOADPRELOAD

Preload is a Preload is a passive stretching forcepassive stretching force exerted exerted on the ventricular muscle at the end of diastole on the ventricular muscle at the end of diastole or just before systoleor just before systole

It is work imposed on heart before contraction It is work imposed on heart before contraction begins.begins.

Preload is caused by the volume of blood in Preload is caused by the volume of blood in the ventricle at the end of diastole.the ventricle at the end of diastole.

It is determined by venous return and stretch It is determined by venous return and stretch of muscle fibre.of muscle fibre.

FRANK STARLING’S LAWFRANK STARLING’S LAW

Force of myocardial contraction is determined Force of myocardial contraction is determined by the length of muscle cell fibersby the length of muscle cell fibers

Increasing myocardial stretch increases the Increasing myocardial stretch increases the force of systoleforce of systole

Amount of blood entering right atrium (CVP)Amount of blood entering right atrium (CVP)

Right heart preload decrease when person Right heart preload decrease when person holds breath and bear down and vice versaholds breath and bear down and vice versa

AFTERLOADAFTERLOADAfterload is the force or pressure against Afterload is the force or pressure against which a cardiac chamber must eject blood which a cardiac chamber must eject blood during systoleduring systoleThe most critical factor determining The most critical factor determining afterload is vascular resistance : systemic afterload is vascular resistance : systemic vascular resistance (LV) and pulmonary vascular resistance (LV) and pulmonary vascular resistancevascular resistance (RV).(RV).Decrease SVR will increase SV and vice Decrease SVR will increase SV and vice versa.versa.Afterload increases in stenosis of aortic Afterload increases in stenosis of aortic valve.valve.

CONTRACTILITYCONTRACTILITY

Contractility refers to the ability of cardiac Contractility refers to the ability of cardiac muscle fibers to shorten when stimulated muscle fibers to shorten when stimulated and is considered to be independent of and is considered to be independent of preload and afterload.preload and afterload.

It is strongly influenced by number of It is strongly influenced by number of calcium ions that are available to calcium ions that are available to participate in the contractile process (actin participate in the contractile process (actin myosin filament interaction)myosin filament interaction)

PATIENT ASSESSMENTPATIENT ASSESSMENTCARDIOVASCULAR SYSTEMCARDIOVASCULAR SYSTEM

HISTORY OF PRESENT ILLNESSHISTORY OF PRESENT ILLNESSSymptoms analysis: normal baseline, onset, Precipitating and Symptoms analysis: normal baseline, onset, Precipitating and palliative factors, quantity and quality, region and radiation, palliative factors, quantity and quality, region and radiation, severity and time.severity and time. Chest painChest painNausea and/or vomitingNausea and/or vomitingDyspneaDyspneaEdemaEdemaPalpitationsPalpitationsSyncope/dizzinessSyncope/dizzinessCough and hemoptysisCough and hemoptysisCyanosisCyanosisExtremity pain or paresthesiasExtremity pain or paresthesiasFatigueFatigueOrthopneaOrthopneaPast medical historyPast medical historyMedicationsMedicationsRisk factors (age, diet, smoking, sedentary life style etc)Risk factors (age, diet, smoking, sedentary life style etc)

PHYSICAL EXAMPHYSICAL EXAM

InspectionInspection

– General appearance General appearance – Jugular venous Jugular venous

distension (JVD)distension (JVD)– SkinSkin– ExtremitiesExtremities

PalpationPalpation– Pulses Pulses

Percussion Percussion

AuscultationAuscultation– Good stethoscope Good stethoscope – PositioningPositioning

– Normal tones – SNormal tones – S11/S/S22

– Murmurs Murmurs

MURMURS MURMURS

Timing Timing

Location Location

Transmission Transmission

Pitch Pitch

Quality Quality

IntensityIntensity

Grade 1 – Barely audible Grade 1 – Barely audible

Grade 2 – Clearly audible Grade 2 – Clearly audible

Grade 3 – Moderately Grade 3 – Moderately loud loud

Grade 4 – Loud with a Grade 4 – Loud with a thrill thrill

Grade 5 – Very loud with Grade 5 – Very loud with an easily palpable thrill an easily palpable thrill

Grade 6 – Very loud, no Grade 6 – Very loud, no stethoscope needed, stethoscope needed, palpable and visible thrillpalpable and visible thrill

IMPORTANT CARDIAC LABSIMPORTANT CARDIAC LABS

Coagulation studies – PTT, APTT and PT/INR, Coagulation studies – PTT, APTT and PT/INR, platelet, fibrinogen level etc.platelet, fibrinogen level etc.Electrolytes – Potassium, magnesium, and calcium.Electrolytes – Potassium, magnesium, and calcium.Lipid studies – Cholesterol, LDL, HDL, triglycerides.Lipid studies – Cholesterol, LDL, HDL, triglycerides.Enzymes – CK-MM, CK-MB, CK-BB, Troponin.Enzymes – CK-MM, CK-MB, CK-BB, Troponin.Hematological studies – RBC, HB, HCT, WBC, ESRHematological studies – RBC, HB, HCT, WBC, ESRBlood chemistry – electrolytes, ABGs, BUN, Cr, Blood chemistry – electrolytes, ABGs, BUN, Cr, proteins etc.proteins etc.CRP, D- dimerCRP, D- dimer

DIAGNOSTIC STUDIESDIAGNOSTIC STUDIESStandard 12 lead Electrocardiogram.Standard 12 lead Electrocardiogram.

Continuous cardiac monitoringContinuous cardiac monitoring

Electrophysiology studies (Holter monitoring)Electrophysiology studies (Holter monitoring)

Chest radiographyChest radiography

EchocardiographyEchocardiography

TransesophagealTransesophageal EchocardiographyEchocardiography

Exercise stress testingExercise stress testing

CT scanningCT scanning

MRI MRI

Cardiac catheterizationCardiac catheterization

Coronary angiographyCoronary angiography

12 LEAD 12 LEAD ELECTROCARDIOGRAM (ECG)ELECTROCARDIOGRAM (ECG)

The electrocardiogram is a graphic record of The electrocardiogram is a graphic record of the direction and magnitude of the electrical the direction and magnitude of the electrical activity that is generated by the depolarization activity that is generated by the depolarization and repolarization of the atria and ventricles.and repolarization of the atria and ventricles.The electrocardiogram (ECG) is a The electrocardiogram (ECG) is a representation of the electrical events of the representation of the electrical events of the cardiac cycle.cardiac cycle.Each event has a distinctive waveform, the Each event has a distinctive waveform, the study of which can lead to greater insight into a study of which can lead to greater insight into a patient’s cardiac pathophysiology.patient’s cardiac pathophysiology.

Cont.Cont.

P wave of ECG represents depolarization P wave of ECG represents depolarization of SA nodeof SA node

QRS complex represents depolarization of QRS complex represents depolarization of ventricular conduction systemventricular conduction system

T wave occur during the last half of systole T wave occur during the last half of systole and represents repolarization of the and represents repolarization of the ventriclesventricles

CHEST LEADSCHEST LEADSV1:V1: fourth intercostal space, right of the fourth intercostal space, right of the

sternum. sternum. V2:V2: fourth intercostal space to the left of the fourth intercostal space to the left of the

sternum. sternum. V3:V3: Between leads V2 and V4 Between leads V2 and V4V4:V4: fifth intercostal space in the mid-clavicular fifth intercostal space in the mid-clavicular

linelineV5:V5: horizontally even with V4, but in the horizontally even with V4, but in the

anterior axillary line.anterior axillary line.V6:V6: horizontally even with V4 and V5 in the horizontally even with V4 and V5 in the

midaxillary line.midaxillary line.

LIMB LEADSLIMB LEADS

RA:RA: on the right arm. on the right arm.

LA:LA: on the left arm. on the left arm.

RL:RL: on the right leg. (ground lead or earth lead) on the right leg. (ground lead or earth lead)

LL:LL: on the left leg. on the left leg.

Lead I is the voltage between the left arm (LA) Lead I is the voltage between the left arm (LA) electrode and right arm (RA) electrode. electrode and right arm (RA) electrode.

Lead II is the voltage between the left leg (LL) Lead II is the voltage between the left leg (LL) electrode and the right arm (RA) electrode. electrode and the right arm (RA) electrode.

Lead III is the voltage between the left leg (LL) Lead III is the voltage between the left leg (LL) electrode and the left arm (LA) electrode.electrode and the left arm (LA) electrode.

AUGMENTED LEADSAUGMENTED LEADS

Lead Lead augmented vector right (aVR)augmented vector right (aVR) has the has the positive electrode on the right arm. The negative positive electrode on the right arm. The negative electrode is a combination of the left arm electrode is a combination of the left arm electrode and the left leg electrode. electrode and the left leg electrode. Lead Lead augmented vector left (aVL)augmented vector left (aVL) has the has the positive electrode on the left arm. The negative positive electrode on the left arm. The negative electrode is a combination of the right arm electrode is a combination of the right arm electrode and the left leg electrode. electrode and the left leg electrode. Lead Lead augmented vector foot (aVF)augmented vector foot (aVF) has the has the positive electrode on the left leg. The negative positive electrode on the left leg. The negative electrode is a combination of the right arm electrode is a combination of the right arm electrode and the left arm electrode. electrode and the left arm electrode.

CONT.CONT.

Each lead has both a positive and a Each lead has both a positive and a negative pole.negative pole.

When electrical current travel along When electrical current travel along towards a positive pole, waveform is an towards a positive pole, waveform is an upward deflection.upward deflection.

When current travels toward a negative When current travels toward a negative pole, deflection is downward.pole, deflection is downward.

ECG PAPERECG PAPER

The measurement of time is calculated The measurement of time is calculated along the horizontal lines in seconds.along the horizontal lines in seconds.– Each small square = 0.04 secEach small square = 0.04 sec– Each large square = 0.20 secEach large square = 0.20 sec– 5 large boxes = 1 sec5 large boxes = 1 sec

Measurement of energy (voltage or Measurement of energy (voltage or amplitude) is represented along the amplitude) is represented along the vertical lines in millivolts or millimeters.vertical lines in millivolts or millimeters.– Each small square = 0.1 mV or 1 mmEach small square = 0.1 mV or 1 mm– Each large square = 0.5 mV or 5 mmEach large square = 0.5 mV or 5 mm

What types of pathology can we What types of pathology can we identify and study from EKGs?identify and study from EKGs?

ArrhythmiasArrhythmiasMyocardial ischemia and infarctionMyocardial ischemia and infarctionPericarditisPericarditisChamber hypertrophyChamber hypertrophyElectrolyte disturbances (i.e. Electrolyte disturbances (i.e. hyperkalemia, hypokalemia)hyperkalemia, hypokalemia)Drug toxicity (i.e. digoxin and drugs which Drug toxicity (i.e. digoxin and drugs which prolong the QT interval)prolong the QT interval)

ECG WAVEFORMSECG WAVEFORMS

The baseline is also known as the The baseline is also known as the isoelectric line.isoelectric line.

The heart’s electrical activity produces The heart’s electrical activity produces several waveforms.several waveforms.

The waveforms are:The waveforms are:– P waveP wave– QRS complexQRS complex– T waveT wave

P WAVEP WAVE

Measured from the beginning of the P Measured from the beginning of the P wave to the end of P wave.wave to the end of P wave.

It represents Atrial depolarization.It represents Atrial depolarization.

Normal P wave precedes a QRS complex.Normal P wave precedes a QRS complex.

To evaluate P wave look for three To evaluate P wave look for three characteristics:characteristics:– LocationLocation– ConfigurationConfiguration– DeflectionDeflection

CONT.CONT.

If all of the P waves do not look alike then If all of the P waves do not look alike then the impulse may be coming in the atria the impulse may be coming in the atria and not the SA node.and not the SA node.If pacemaker site is in the atria, P waves If pacemaker site is in the atria, P waves are upright (positive deflection).are upright (positive deflection).If it’s at AV junction, they may be inverted If it’s at AV junction, they may be inverted in lead II.in lead II.It is normally 2.5mm or less in height and It is normally 2.5mm or less in height and 0.11 sec or less in duration.0.11 sec or less in duration.

QRS COMPLEXQRS COMPLEX

Q wave: Q wave: is the first is the first negative deflectionnegative deflection following the P wave.following the P wave.

R wave: R wave: the first the first positive deflectionpositive deflection extending above baseline following the P extending above baseline following the P wave and Q wave.wave and Q wave.

S wave: S wave: is the first is the first negative deflectionnegative deflection extending below baseline following the R extending below baseline following the R wave.wave.

CONT.CONT.

QRS complex represents the ventricular QRS complex represents the ventricular depolarization (ventricular systole).depolarization (ventricular systole).

Normal duration of QRS complex is 0.04 Normal duration of QRS complex is 0.04 to 0.12 seconds.to 0.12 seconds.

It is measured from the beginning of the Q It is measured from the beginning of the Q wave (where it begins to deviate from the wave (where it begins to deviate from the baseline) to the end of the S wave (where baseline) to the end of the S wave (where the S wave returns to the isoelectric line).the S wave returns to the isoelectric line).

T WAVET WAVE

T wave represents ventricular T wave represents ventricular repolarization (ventricular diastole).repolarization (ventricular diastole).

The end of the T wave is the point where it The end of the T wave is the point where it returns to the isoelectric line.returns to the isoelectric line.

T wave always follows the QRS complex.T wave always follows the QRS complex.

Normal T wave is positive and upright.Normal T wave is positive and upright.

Its normal value is .10 sec to 0.25 sec.Its normal value is .10 sec to 0.25 sec.

Inverted or negative deflecting T waves Inverted or negative deflecting T waves are suggestive of myocardial ischemia or are suggestive of myocardial ischemia or ventricular conduction delay.ventricular conduction delay.

CONT.CONT.

Peaked, tall T waves usually indicate Peaked, tall T waves usually indicate Hyperkalemia.Hyperkalemia.

U WAVEU WAVE

The U wave is the first gradual or abrupt slope The U wave is the first gradual or abrupt slope after the end of the T wave.after the end of the T wave.

It probably represents the final stage of It probably represents the final stage of repolarization of the ventricles.repolarization of the ventricles.

U wave are rounded and symmetrical.U wave are rounded and symmetrical.

U waves are measured from the beginning of U waves are measured from the beginning of the U wave to the end of the U wave.the U wave to the end of the U wave.

Prominent U waves may indicate hypokalemia Prominent U waves may indicate hypokalemia and also the effect of an excessive amount of and also the effect of an excessive amount of digoxin in conduction system.digoxin in conduction system.

P-R INTERVAL P-R INTERVAL

P-R interval represents the interval of time P-R interval represents the interval of time between atrial depolarization and between atrial depolarization and ventricular depolarization.ventricular depolarization.

A normal P-R interval indicates that the A normal P-R interval indicates that the electrical impulse is being conducted and electrical impulse is being conducted and travels through the atria, AV node, AV travels through the atria, AV node, AV junction, bundle of His, bundle branches junction, bundle of His, bundle branches and Purkinje fibers.and Purkinje fibers.

CONT.CONT.

The P-R interval is measured from the The P-R interval is measured from the beginning of the P wave to the beginning beginning of the P wave to the beginning of the QRS complex.of the QRS complex.

Normal duration of P-R interval is 0.12 to Normal duration of P-R interval is 0.12 to 0.20 seconds.0.20 seconds.

QRS COMPLEXQRS COMPLEX

It is a large waveform representing It is a large waveform representing ventricular depolarization. ventricular depolarization.

Not all QRS complex has all three Not all QRS complex has all three componentscomponents

Measured from the starting of Q wave till Measured from the starting of Q wave till end of S waveend of S wave

Normal QRS complex is 0.06 to 0.11 Normal QRS complex is 0.06 to 0.11 seconds. seconds.

ST SEGMENTST SEGMENT

The ST segment marks the beginning of The ST segment marks the beginning of the ventricular repolarization.the ventricular repolarization.The ST segment extends from the end of The ST segment extends from the end of the QRS complex to the beginning of the T the QRS complex to the beginning of the T wave.wave.A normal ST segment is flat on the A normal ST segment is flat on the isoelectric line or baseline.isoelectric line or baseline.Elevated or depressed more than 1mm of Elevated or depressed more than 1mm of ST segment may be indicative of an MI.ST segment may be indicative of an MI.

ST SEGMENTST SEGMENT DEPRESSION ELEVATIONDEPRESSION ELEVATION

QT INTERVALQT INTERVALThe QT interval represents the length of time The QT interval represents the length of time for both ventricular depolarization and for both ventricular depolarization and repolarization.repolarization.It is measured from the beginning of the Q It is measured from the beginning of the Q wave to the end of the T wave on the isoelectric wave to the end of the T wave on the isoelectric line.line.Its normal value is 0.32 to 0.43 sec.Its normal value is 0.32 to 0.43 sec.A short QT interval may indicate a A short QT interval may indicate a hypercalcemia in patients taking digitalis.hypercalcemia in patients taking digitalis.A prolong QT interval is caused by A prolong QT interval is caused by antiarrhythmatics or may indicate antiarrhythmatics or may indicate HypocalcemiaHypocalcemia

NORMAL QT INTERVALNORMAL QT INTERVAL

PROLONG QT INTERVALPROLONG QT INTERVAL

STEPS TO READING ECGSTEPS TO READING ECG

Is the Is the RhythmRhythm regular or irregular? regular or irregular?

What is the What is the RateRate? Both atrial and ventricle.? Both atrial and ventricle.

Do the Do the P wavesP waves all look the same? Is there all look the same? Is there a P wave for every QRS and conversely a a P wave for every QRS and conversely a QRS complexQRS complex for every P wave? for every P wave?

Are all the complexes within Are all the complexes within Normal Time Normal Time LimitsLimits? (PR interval, QRS complex and ST ? (PR interval, QRS complex and ST segment)segment)

IdentifyIdentify the rhythm and any abnormalities. the rhythm and any abnormalities.

RATERATE

6 SECOND METHOD:6 SECOND METHOD:

It is performed only if the rhythm is regular.It is performed only if the rhythm is regular.

Identify a 6 second strip.Identify a 6 second strip.

Locate 3 second markers (30 large boxes).Locate 3 second markers (30 large boxes).

Count complete QRS complex in a 6-second Count complete QRS complex in a 6-second strip and multiply it by 10. strip and multiply it by 10.

This gives you an approximate number of This gives you an approximate number of beats per minutes.beats per minutes.

CONT.CONT.

THE SEQUENCE METHOD:THE SEQUENCE METHOD:

Locate an R wave on a dark black line of a Locate an R wave on a dark black line of a large box.large box.

Label the consecutive heavy black lines as Label the consecutive heavy black lines as follows: 300, 150, 100, 75, 60 and 50.follows: 300, 150, 100, 75, 60 and 50.

If next R wave falls in between two heavy If next R wave falls in between two heavy black lines for e.g. between 70 and 60 black lines for e.g. between 70 and 60 then the heart rate would be 65.then the heart rate would be 65.

# Of Big # Of Big BoxesBoxes

RateRate

11 300300

22 150150

33 100100

44 7575

55 6060

66 5050

NORMAL INTERVAL TIMINGNORMAL INTERVAL TIMING

PR interval – 0.12 to 0.20 seconds PR interval – 0.12 to 0.20 seconds

QRS interval – less then 0.12QRS interval – less then 0.12

QT interval – varies with rate. QT interval – varies with rate.

DETERMINATION OF CARDIAC DETERMINATION OF CARDIAC RHYTHMRHYTHM

Correct determination of cardiac rhythm Correct determination of cardiac rhythm requires a systematic evaluation of ECG.requires a systematic evaluation of ECG.

Following steps are used to determine Following steps are used to determine cardiac rhythm:cardiac rhythm:– Calculate the atrial rate (P wave)Calculate the atrial rate (P wave)– Calculate ventricular rate (QRS complex)Calculate ventricular rate (QRS complex)– Determine regularity and shape of P waveDetermine regularity and shape of P wave– Determine regularity, shape and width of QRSDetermine regularity, shape and width of QRS

– Measure the PR intervalMeasure the PR interval– Interpret the arrhythmia Interpret the arrhythmia

COMMON ARRHYTHMIASCOMMON ARRHYTHMIAS

Arrhythmias originating in the sinus node.Arrhythmias originating in the sinus node.

Arrhythmias originating in the atria.Arrhythmias originating in the atria.

Arrhythmias originating in the junction.Arrhythmias originating in the junction.

Arrhythmias originating in the ventricles.Arrhythmias originating in the ventricles.

Atrioventricular BlocksAtrioventricular Blocks

NORMAL SINUS RHYTHMNORMAL SINUS RHYTHMNormal sinus rhythm record an impulse that start in Normal sinus rhythm record an impulse that start in the sinus node and progresses to the ventricles the sinus node and progresses to the ventricles through a normal conduction pathway.through a normal conduction pathway.

Atrial and ventricular rhythms: regularAtrial and ventricular rhythms: regular

Atrial and ventricular rates: 60 – 100 bpmAtrial and ventricular rates: 60 – 100 bpm

P waves: rounded, smooth, upright and preceding P waves: rounded, smooth, upright and preceding every QRS complex.every QRS complex.

PR interval: 0.12 to 0.20 seconds.PR interval: 0.12 to 0.20 seconds.

QRS complex: 0.04 to 0.10 sec, less than 0.12 secQRS complex: 0.04 to 0.10 sec, less than 0.12 sec

T wave: uprightT wave: upright

QT interval: 0.36 sec to 0.44 secQT interval: 0.36 sec to 0.44 sec

SINUS ARRHYTHMIASINUS ARRHYTHMIA

Sinus arrhythmia occurs when the sinus Sinus arrhythmia occurs when the sinus node discharges irregularly.node discharges irregularly.

Associated with the phases of respiration: Associated with the phases of respiration: during inspiration sinus node fires faster during inspiration sinus node fires faster and vice versa.and vice versa.

Looks like normal sinus rhythm except for Looks like normal sinus rhythm except for the sinus irregularity.the sinus irregularity.

SINUS BRADYCARDIASINUS BRADYCARDIA

Sinus bradycardia is characterized by a sinus Sinus bradycardia is characterized by a sinus rate below 60 bpm and regular rhythm.rate below 60 bpm and regular rhythm.

It may occur normally during sleep or in a It may occur normally during sleep or in a person with a well conditioned heart (athletes).person with a well conditioned heart (athletes).

May be a response of vagal stimulation, any May be a response of vagal stimulation, any disease process (MI, raised ICP etc) and disease process (MI, raised ICP etc) and medications (digitalis, beta blockers, Ca medications (digitalis, beta blockers, Ca Channel blocker).Channel blocker).

Treat only if patient is symptomatic.Treat only if patient is symptomatic.

SINUS TACHYCARDIASINUS TACHYCARDIA

Sinus tachycardia is a sinus rhythm at a Sinus tachycardia is a sinus rhythm at a rate greater than 100 bpm.rate greater than 100 bpm.It is normal response to exercise and It is normal response to exercise and emotion.emotion.Persistent sinus tachycardia indicates Persistent sinus tachycardia indicates underlying problem like fever, acute blood underlying problem like fever, acute blood loss, pain, shock, anxiety etc.loss, pain, shock, anxiety etc.It is normal physiologic response to It is normal physiologic response to decrease cardiac output.decrease cardiac output.

SINUS ARRESTSINUS ARREST

Sinus arrest is a failure of the SA node to Sinus arrest is a failure of the SA node to initiate an impulse resulting in the absence initiate an impulse resulting in the absence of a P wave, QRS complex and T wave.of a P wave, QRS complex and T wave.

It is also known as sinus pause or cardiac It is also known as sinus pause or cardiac sandstill.sandstill.

Usually with the exception of missing Usually with the exception of missing PQRST complex, the ECG will be normal.PQRST complex, the ECG will be normal.

ATRIAL ARRHYTHMIASATRIAL ARRHYTHMIAS

Atrial arrhythmias the most common Atrial arrhythmias the most common cardiac rhythm disturbance as result from cardiac rhythm disturbance as result from impulses originating in areas outside the impulses originating in areas outside the sinoatrial node (SA node).sinoatrial node (SA node).

These arrhythmias can affect ventricular These arrhythmias can affect ventricular filling time.filling time.

PREMATURE ATRIALPREMATURE ATRIAL CONTRACTIONCONTRACTION

Premature atrial contraction originates Premature atrial contraction originates outside the SA node, usually results from outside the SA node, usually results from an irritable focus (ectopic pacemaker).an irritable focus (ectopic pacemaker).

Irritable focus in the atria fires before the Irritable focus in the atria fires before the next sinus node impulse is due to fire.next sinus node impulse is due to fire.

P wave configuration is abnormal as P wave configuration is abnormal as compare to sinus P wave.compare to sinus P wave.

Normal QRS complex .Normal QRS complex .

CONT.CONT.

Rhythm would be regular except when Rhythm would be regular except when PAC occur.PAC occur.PR interval may be normal or prolonged.PR interval may be normal or prolonged.T wave embedded with p wave.T wave embedded with p wave.It can occur in healthy people as a result of It can occur in healthy people as a result of emotions, tobacco, alcohol and caffeine.emotions, tobacco, alcohol and caffeine.It can also associated with disease It can also associated with disease processes like rheumatic heart diseases, processes like rheumatic heart diseases, ischemic heart diseases, mitral stenosis, ischemic heart diseases, mitral stenosis, heart failure, certain electrolyte imbalances heart failure, certain electrolyte imbalances and medications etc.and medications etc.

PAROXYSMAL SUPRAVENTRICULAR PAROXYSMAL SUPRAVENTRICULAR TACHYCARDIATACHYCARDIA

PSVT is the sudden onset of a rapid firing PSVT is the sudden onset of a rapid firing from an ectopic foci resulting in a heart from an ectopic foci resulting in a heart rate of 150 – 250 bpm.rate of 150 – 250 bpm.

Occurs when a single ectopic site in one Occurs when a single ectopic site in one of the atria takes over pacing the heart of the atria takes over pacing the heart instead of the SA node.instead of the SA node.

The brief period of tachycardia alternates The brief period of tachycardia alternates with periods of normal sinus rhythm.with periods of normal sinus rhythm.

CONT.CONT.

P wave may precede QRS complex, may be P wave may precede QRS complex, may be hidden in QRS complex or may be merged hidden in QRS complex or may be merged with T wave.with T wave.P wave may be negative because of P wave may be negative because of retrograde conduction from AV node to atria.retrograde conduction from AV node to atria.QRS complex is usually normal.QRS complex is usually normal.Rhythm of PSVT is regular.Rhythm of PSVT is regular.PSVT can be terminated with vagal PSVT can be terminated with vagal stimulation (carotid massage), Valsalva stimulation (carotid massage), Valsalva maneuver or IV adenosine.maneuver or IV adenosine.

ATRIAL FLUTTERATRIAL FLUTTER

Atrial flutter is an accelerated rhythm from Atrial flutter is an accelerated rhythm from rapid firing of an ectopic atrial focus at rate rapid firing of an ectopic atrial focus at rate of 250 to 350 bpm.of 250 to 350 bpm.

The AV node prevent too many atrial The AV node prevent too many atrial impulses from reaching to the ventricles.impulses from reaching to the ventricles.

Rapid atrial rate produces Rapid atrial rate produces saw tooth saw tooth P P waves on the ECG.waves on the ECG.

CONT.CONT.

P wave has classic saw tooth appearance P wave has classic saw tooth appearance with atrial rate of 250 – 350 bpm.with atrial rate of 250 – 350 bpm.Flutter block; 2:1, 3:1 or 4:1 (flutter to Flutter block; 2:1, 3:1 or 4:1 (flutter to ventricular ratio).ventricular ratio).QRS has normal configuration.QRS has normal configuration.Atrial rhythm is regular but ventricular Atrial rhythm is regular but ventricular rhythm would be regular or irregular both.rhythm would be regular or irregular both.Treatment goal is to reestablish sinus Treatment goal is to reestablish sinus rhythm and ventricular control.rhythm and ventricular control.

ATRIAL FIBRILLATIONATRIAL FIBRILLATION

Atrial fibrillation is characterized by rapid, Atrial fibrillation is characterized by rapid, chaotic atrial ectopic rhythm with atrial rate chaotic atrial ectopic rhythm with atrial rate of 350 – 500 bpm.of 350 – 500 bpm.

The ventricles respond only to those The ventricles respond only to those impulses that make it through AV node.impulses that make it through AV node.

P waves are not present.P waves are not present.

Normal QRS complex.Normal QRS complex.

Rhythm is irregular.Rhythm is irregular.

MULTIFOCAL ATRIAL MULTIFOCAL ATRIAL TACHYCARDIATACHYCARDIA

In this arrhythmia, atrial tachycardia In this arrhythmia, atrial tachycardia occurs with three or more atrial foci firing occurs with three or more atrial foci firing intermittently.intermittently.

P wave morphology results from firing of P wave morphology results from firing of three or more atrial foci.three or more atrial foci.

Atrial rate is between 100 to 250 bpm.Atrial rate is between 100 to 250 bpm.

Rhythm is usually irregular.Rhythm is usually irregular.

QRS complex are normal.QRS complex are normal.

JUNCTIONAL RHYTHMJUNCTIONAL RHYTHM

Junctional rhythm originates from AV junction.Junctional rhythm originates from AV junction.

It occurs when SA node fails to conduct It occurs when SA node fails to conduct impulses.impulses.

The Junctional rate ranges between 50 to 70 The Junctional rate ranges between 50 to 70 bpm.bpm.

P wave appear inverted before QRS complex.P wave appear inverted before QRS complex.

Buried P wave inside the QRS complex.Buried P wave inside the QRS complex.

Normal QRS followed by inverted P wave.Normal QRS followed by inverted P wave.

PREMATURE JUNCTIONAL PREMATURE JUNCTIONAL CONTRACTIONCONTRACTION

Premature junctional contraction is an Premature junctional contraction is an ectopic impulse from AV junction occur ectopic impulse from AV junction occur before next sinus impulse.before next sinus impulse.QRS complex is narrow <0.12 sec.QRS complex is narrow <0.12 sec.P wave may occur before, during or after P wave may occur before, during or after QRS complex.QRS complex.Occur in healthy people or in people with Occur in healthy people or in people with underlying heart disease.underlying heart disease.Rhythm is irregular.Rhythm is irregular.

PREMATURE VENTRICULAR PREMATURE VENTRICULAR CONTRACTIONCONTRACTION

They are caused by firing of an ectopic They are caused by firing of an ectopic impulse in the ventricles before next impulse in the ventricles before next expected impulse from SA node.expected impulse from SA node.

As a result of this, no P wave occur.As a result of this, no P wave occur.

QRS complex is wide and bizarre appears QRS complex is wide and bizarre appears interrupting normal sinus rhythm.interrupting normal sinus rhythm.

After a premature beat there is a After a premature beat there is a compensatory pause.compensatory pause.

CONT.CONT.

If PVC occur after each sinus beat then it If PVC occur after each sinus beat then it is known as ventricular bigeminy.is known as ventricular bigeminy.

If PVC occur after two consecutive sinus If PVC occur after two consecutive sinus beats then it is known as ventricular beats then it is known as ventricular trigeminy. trigeminy.

When PVC appear in one form it is called When PVC appear in one form it is called as unifocal PVC and different PVC are as unifocal PVC and different PVC are known as multifocal PVC.known as multifocal PVC.

VENTRICULAR TACHYCARDIAVENTRICULAR TACHYCARDIA

This is characterized by rapidly occurring This is characterized by rapidly occurring series of PVCs with no normal beats in series of PVCs with no normal beats in between.between.Absent P wave.Absent P wave.QRS is wide and bizarre with rate more QRS is wide and bizarre with rate more than 100 to 250 bpm.than 100 to 250 bpm.Rhythm is regular.Rhythm is regular.Extremely dangerous as this can result in Extremely dangerous as this can result in low cardiac output.low cardiac output.

TOSARDES DE POINTESTOSARDES DE POINTES

Tosardes de pointes means twisting of points, Tosardes de pointes means twisting of points, is a special form of ventricular tachycardia.is a special form of ventricular tachycardia.QRS complexes rotate about the baseline, QRS complexes rotate about the baseline, deflecting downward and upward for several deflecting downward and upward for several beats.beats.P waves are absent.P waves are absent.QRS complex is wide and bizarre.QRS complex is wide and bizarre.Tachycardia rate is between 100 – 300 bpm.Tachycardia rate is between 100 – 300 bpm.Rhythm is irregular.Rhythm is irregular.IV magnesium sulphate is drug of choice.IV magnesium sulphate is drug of choice.

VENTRICULAR FIBRILLATIONVENTRICULAR FIBRILLATION

Ventricular defibrillation is rapid, irregular Ventricular defibrillation is rapid, irregular and ineffective depolarization of the and ineffective depolarization of the ventricles.ventricles.

ECG tracing display bizarre fibrillatory ECG tracing display bizarre fibrillatory wave pattern.wave pattern.

P wave, QRS complex and T wave are P wave, QRS complex and T wave are impossible to identify.impossible to identify.

Rate and rhythm cannot be determined.Rate and rhythm cannot be determined.

IDIOVENTRICULAR RHYTHMIDIOVENTRICULAR RHYTHM

Normal ventricular rate is 20 to 40 bpm Normal ventricular rate is 20 to 40 bpm and when this rate accelerates above and when this rate accelerates above sinus rate making ventricle the primary sinus rate making ventricle the primary pacemaker.pacemaker.

Absent P wave.Absent P wave.

QRS is wide and bizarre.QRS is wide and bizarre.

It occur regularly at rate of 50 to 100 bpm.It occur regularly at rate of 50 to 100 bpm.

Rhythm is usually regular.Rhythm is usually regular.

VENTRICULAR ASYSTOLEVENTRICULAR ASYSTOLE

It is absence of any electrical activity.It is absence of any electrical activity.

No P wave, no QRS complex, no pulse and No P wave, no QRS complex, no pulse and no cardiac output.no cardiac output.

It is always fatal as patient is unresponsive It is always fatal as patient is unresponsive therefore it has to be treated immediately.therefore it has to be treated immediately.

Flat line on ECG.Flat line on ECG.

ATRIOVENTRICULAR BLOCKATRIOVENTRICULAR BLOCK

The termThe term Atrioventricular Atrioventricular block is used to block is used to describe describe arrhythmias in arrhythmias in which there is which there is delay or failed delay or failed conduction of conduction of supraventricular supraventricular impulses into the impulses into the ventricles.ventricles.

FIRST DEGREE FIRST DEGREE ATRIOVENTRICULAR BLOCKATRIOVENTRICULAR BLOCK

First degree AV block is defined as First degree AV block is defined as prolonged AV conduction time of prolonged AV conduction time of supraventricular impulses into the supraventricular impulses into the ventricles.ventricles.This delay usually occur in the AV node This delay usually occur in the AV node and all impulses are conducted to the and all impulses are conducted to the ventricles but with delayed conduction ventricles but with delayed conduction times.times.It is characterized by a constant prolong It is characterized by a constant prolong PR interval.PR interval.

CONT.CONT.

P waves are present and preceding every P waves are present and preceding every QRS complex.QRS complex.

It can be due to coronary artery disease, It can be due to coronary artery disease, rheumatic heart disease, administration of rheumatic heart disease, administration of digitalis, beta blockers or ca channel digitalis, beta blockers or ca channel blockers.blockers.

Nurse should observe rhythm closely for 2 Nurse should observe rhythm closely for 2 degree and 3 degree block.degree and 3 degree block.

SECOND DEGREE AV BLOCKSECOND DEGREE AV BLOCK

Second degree AV block occur when Second degree AV block occur when impulses from AV node at time fails to be impulses from AV node at time fails to be conducted to the ventricles.conducted to the ventricles.

It is divided into two distinct categories: It is divided into two distinct categories: type I block occurring in the AV node and type I block occurring in the AV node and type II occurring below the AV node in the type II occurring below the AV node in the bundle of His or bundle branch system.bundle of His or bundle branch system.

SECOND DEGREE AV BLOCK SECOND DEGREE AV BLOCK MOBITZ I (WENCHEBACK)MOBITZ I (WENCHEBACK)

It refer to as Wencheback block in which It refer to as Wencheback block in which there is a progressive increase in there is a progressive increase in conduction times of consecutive atrial conduction times of consecutive atrial impulses into the ventricles until one impulses into the ventricles until one impulse fails to conduct.impulse fails to conduct.It is usually associated with the block It is usually associated with the block above the bundle of His.above the bundle of His.PR interval gradually lengthen until one P PR interval gradually lengthen until one P wave fails to conduct and is not followed wave fails to conduct and is not followed by QRS.by QRS.

SECOND DEGREE AV BLOCKSECOND DEGREE AV BLOCKMOBITZ II MOBITZ II

This type of block is due to sudden failure of This type of block is due to sudden failure of conduction of an atrial impulse to the ventricles conduction of an atrial impulse to the ventricles without progressive increase in conduction time of without progressive increase in conduction time of consecutive P waves.consecutive P waves.

This is less common than Mobitz Type I but is more This is less common than Mobitz Type I but is more serious (often precedes to 3 degree block).serious (often precedes to 3 degree block).

Conduction pattern would be occasionally or Conduction pattern would be occasionally or repetitive, 2:1, 3:1,…repetitive, 2:1, 3:1,…

PR interval remain constant although they may be PR interval remain constant although they may be normal or slightly prolong.normal or slightly prolong.

Wide QRS complex due to bundle branch block.Wide QRS complex due to bundle branch block.

THIRD DEGREE AV BLOCKTHIRD DEGREE AV BLOCK

Complete AV block occurs when no P Complete AV block occurs when no P waves are conducted to the ventricles.waves are conducted to the ventricles.

It is complete failure of conduction of all It is complete failure of conduction of all atrial impulses to ventricles.atrial impulses to ventricles.

The atria and ventricle are controlled by The atria and ventricle are controlled by independent pacemaker.independent pacemaker.

P waves and QRS are present on ECG P waves and QRS are present on ECG but without relationship.but without relationship.

SUMMARY OF LEADSSUMMARY OF LEADS

Limb LeadsLimb Leads Precordial LeadsPrecordial Leads

BipolarBipolar I, II, IIII, II, III(standard limb leads)(standard limb leads)

--

UnipolarUnipolar aVR, aVL, aVF aVR, aVL, aVF (augmented limb leads)(augmented limb leads)

VV11-V-V66

PRECORDIAL LEADSPRECORDIAL LEADS

ARRANGEMENT OF LEADS ON THE ARRANGEMENT OF LEADS ON THE ECG PAPERECG PAPER

ANATOMIC GROUPSANATOMIC GROUPS(SEPTUM)(SEPTUM)

ANATOMIC GROUPSANATOMIC GROUPS(LATERAL WALL)(LATERAL WALL)

ANATOMIC GROUPSANATOMIC GROUPS(INFERIOR WALL)(INFERIOR WALL)

ANATOMIC GROUPSANATOMIC GROUPS(SUMMARY)(SUMMARY)

EFFECT OF ELECTROLYTES ON ECGEFFECT OF ELECTROLYTES ON ECGPOTASSIUM:POTASSIUM:– It is found primarily in the intracellular It is found primarily in the intracellular

compartment.compartment.– It is important for cardiac cell repolarization.It is important for cardiac cell repolarization.– It also helps in maintaining stable polarized It also helps in maintaining stable polarized

state of cardiac cells.state of cardiac cells.– Two abnormalities of potassium are Two abnormalities of potassium are

hyperkalemia and hypokalemia. hyperkalemia and hypokalemia. – Hyperkalemia cause tall, narrow and peaked Hyperkalemia cause tall, narrow and peaked

T wave.T wave.– Hypokalemia indicate presence of prominent Hypokalemia indicate presence of prominent

U wave and short T wave.U wave and short T wave.

CONT.CONT.CALCIUM:CALCIUM:– Calcium is important for initiation and propagation Calcium is important for initiation and propagation

of electrical impulses and myocardial contractility.of electrical impulses and myocardial contractility.– Calcium abnormalities are less common than Calcium abnormalities are less common than

potassium abnormalities.potassium abnormalities.– Hypercalcemia causes shortening of the QT Hypercalcemia causes shortening of the QT

interval as a result of short ST segment.interval as a result of short ST segment.– Sometimes ST depression and T wave inversion Sometimes ST depression and T wave inversion

can also be seen.can also be seen.– Hypocalcemia prolong QT interval as a result of Hypocalcemia prolong QT interval as a result of

prolong ST segment.prolong ST segment.– T wave can be inverted in some cases.T wave can be inverted in some cases.

CARDIAC BIOMARKERSCARDIAC BIOMARKERS

Cardiac markersCardiac markers are substances released are substances released from heart muscles when it is damaged as from heart muscles when it is damaged as a result of an injury.a result of an injury.

Normally these enzymes are present in low Normally these enzymes are present in low amounts in the blood of healthy people.amounts in the blood of healthy people.

Used in conjunction with history, Used in conjunction with history, signs/symptoms, exam and ECG changes signs/symptoms, exam and ECG changes to make diagnosis.to make diagnosis.

CHARACTERISTICSCHARACTERISTICS

Easy to measure.Easy to measure.

Inexpensive.Inexpensive.

Cardiac specific.Cardiac specific.

Direct proportional relationship between Direct proportional relationship between the extent of injury and enzyme levels.the extent of injury and enzyme levels.

Rapid serum levels after injury.Rapid serum levels after injury.

Stay for long time in serum.Stay for long time in serum.

Cardiac Rhythm: SupraventricularCardiac Rhythm: SupraventricularNORMAL SINUS RHYTHMNORMAL SINUS RHYTHMImpuses originate at S-A node at normal rateImpuses originate at S-A node at normal rate

SINUS TACHYCARDIASINUS TACHYCARDIAImpuses originate at S-A node at rapid rateImpuses originate at S-A node at rapid rate

Cardiac Rhythm: SupraventricularCardiac Rhythm: Supraventricular

ATRIAL FLUTTERATRIAL FLUTTERImpulses travel in circular course in atria – No interval between T and PImpulses travel in circular course in atria – No interval between T and P

ATRIAL FIBRILLATIONATRIAL FIBRILLATIONImpuses have chaotic, random pathways in atriaImpuses have chaotic, random pathways in atria

Activation Sequence DisordersActivation Sequence DisordersA-V BLOCK, FIRST DEGREEA-V BLOCK, FIRST DEGREEAtrio-ventricular conduction lengthenedAtrio-ventricular conduction lengthened

A-V BLOCK, SECOND DEGREEA-V BLOCK, SECOND DEGREESudden dropped QRS-complexSudden dropped QRS-complex

Pathophysiological indications of Pathophysiological indications of EKGEKG

Shortened QT interval : Shortened QT interval : Hypercalcemia, some Hypercalcemia, some drugs.drugs.Prolonged QT interval : Prolonged QT interval : Hypocalcemia, some Hypocalcemia, some drugs.drugs.Flattened or inverted T waves : Flattened or inverted T waves : Coronary Coronary ischemia, left ventricular hypertrophy, digoxin ischemia, left ventricular hypertrophy, digoxin effect, some drugs.effect, some drugs.Hyperacute T waves : Hyperacute T waves : Possibly the first Possibly the first manifestation of acute myocardial infarction.manifestation of acute myocardial infarction.Prominent U waves : Prominent U waves : Hypokalemia.Hypokalemia.

GROUP ACTIVITYGROUP ACTIVITY

Cardiac cycle. Preload, afterload and contractility. Cardiac cycle. Preload, afterload and contractility.

12 lead ECG. (waves, intervals and segments). Steps 12 lead ECG. (waves, intervals and segments). Steps in reading ECG, methods of taking heart rate from in reading ECG, methods of taking heart rate from rhythm strip.rhythm strip.

Sinus node arrhythmias.Sinus node arrhythmias.

Atrial arrhythmias.Atrial arrhythmias.

Junctional arrhythmias and idioventricular rhythm.Junctional arrhythmias and idioventricular rhythm.

Ventricular arrhythmias.Ventricular arrhythmias.

Heart block, 1 degree and 2 degree)Heart block, 1 degree and 2 degree)

Heart block 3 degree. Cardiac enzymes.Heart block 3 degree. Cardiac enzymes.