BRADYCARDIA

MOHAN SINGH RAISTAFF NURSEMEDICAL ICU

TELL ME AND I FORGET. TEACH ME AND I REMEMBER. INVOLVE ME AND I LEARNED.

•BENJAMIN FRANKLIN

CIRCULATION

CARDIAC PHYSIOLOGY& PARAMETER

VOLUME

SV=ENDDIASTOLIC VOLUME-ENDSYSTOLIC VOLUME

CARDIAC OUTPUT=HRXSV

AFTERLOAD AND PRELOAD

EF=STROKE VOLUME/END DIASRTOLIC VOLUME

TROPISM

INOTROPIC (CONCRACTILITY)

CHRONOTROPIC (CHANGE HEART RATE)

DROMOTROPIC (CONDUCTION VELOCITY)

BATHMOTROPIC (EXCITABULITY)

LUSITROPIC ( RELAXATION)

CONDUCTION SYSTEM

Cardiac action potential

Atrial action potential

Ventricular action potential

Effective refractory period

Pacemaker potential

CHAMBER PRESSURE

CVP, RVP,PULMONARY ARTERY PRESSURE,

LEFT ATRIAL PRESSURE, LT. VENTRICULAR PRESSURE, AORTIC PRESSURE

BLOOD PRESSURE

PULSE PRESSURE=SBP-DBP

ATREIAL BP=SYSTOLIC (90-140),DIASTOLIC (60-90)

MEAN ARTERIAL PRESSURE=SBP+(2XDBP)/3 (70-105mmHg)

Right atrial pressure (2-6mmHG)

RIGHT VENTRICULAR PRSEEURE (RVP)

SYSTOLIC (SRVP):15-25mmHG

DIASTOLIC (DRVP);0-8mmHg

PULMONARY ARTERY PRESSURE

SYSTOLIC (PASP):15-25mmHg

DIASTOLIC (PADP):8-15mmHg

ROLES OF AUTONOMIC NURVOUS SYSTEMS

SYMPATHETIC PARASYMPATHETIC

ADRENERGIC RECEPTOR

CATECHOLAMINES

EPINEPHRINE/NOREPINEPHRINE

ACETYLCHOLINE

INCREASED HEART RATE, BP,CO,

VASOCONSTRICTION,

DECREASED HR,CO,BP,VASODILATION

REST AND DIGESTFLIGHT OR FIGHT

PHYSIOLOGICAL TACHYCARDIA AND BRADYCARDIA..WHY??

human heart electrical system

INTRODUCTIONHeart rate, or heart pulse, is the speed of

the heartbeat measured by the number of heartbeats per unit of time (bpm).

The heart rate can vary according to the body's physical needs, including the need to absorb oxygen and excrete carbon dioxide.

Activities that can provoke change include physical exercises, sleep, anxiety, stress, illness, ingesting, and drugs.

The normal resting adult human heart rate ranges from 60–100 bpm.

CONT’•Bradycardia is a slow heart rate, defined as below 60 bpm

• Tachycardia is a fast heart rate, defined as above 100 bpm at rest.[ 

•When the heart is not beating in a regular pattern, this is referred to as an arrhythmia, These abnormalities of heart rate sometimes, but not always, indicate disease. 

BRADYCARDIABradycardia: A slow heart rate, usually

defined as less than 60 beats per minute.

 Relative bradycardia is used in explaining a heart rate that, although not actually below 60 BPM, is still considered too slow for the individual's current medical condition.

Absolute bradycardia A waking heart rate below 40 BPM is considered absolute bradycardia.

BRADYCARDIA IN HEALTHYDuring sleep, a slow heartbeat

with rates around 40–50 BPM is common, and is considered normal

Highly trained athletes ( athletic heart syndrome) know as atheletic bradycardia or atheletic associated

cardiomegaly.

CLASSIFICATION1.Atrialrespiratory sinus arrhythmiasinus bradycardiaSick sinus syndrome2.Atrioventricular nodalAn atrioventricular nodal bradycardia or AV

junction rhythm is usually caused by the absence of the electrical impulse from the sinus node.

3.Ventricular: A ventricular bradycardia, also known as ventricular escape rhythm or idioventricular rhythm.

Causes

General causes:1º: Abnormal pacemaker/conduction system (congenital or postsurgical Injury)infectious: SepsisAging.Heart diseases ( myocarditis, cardiomyopathy, heart block,Sick sinus syndrome,Mi)Drugs( beta blocker, calcium channel blocker, digoxin, opioid drugs, antiarrthymias drugs)

CAUSE

2º: Hs & Ts: – Hypoxia – Heart block – H+ ions (acidosis) – Hypothermia – Hyperkalemia, -hypoglycemia- hypothyroidism- hypovolemia

-Trauma (head) -Toxins-Tension pnemothorax-Temponate -Thrombosis

SIGNS AND SYMPTOMSNear-fainting or

fainting (syncope)

DizzinessWeaknessFatigueShortness of

breathChest painsLow BPcyanosis

Confusion or memory problems

Easily tiring during physical activity

Low heart rate

History & examination

R/ORisk factors

use of known causative medicationsage over 70 years

recent myocardial infarction

Surgery

cont’Hypothyroidism

electrolyte disorders

infections

exposure to toxins

infiltrative diseases

sleep apnoea

Key diagnostic factorspresence of risk factors (common)pulse rate below 50 bpm (common)dizziness/lightheadedness (common)syncope (common)fatigue (common)exercise intolerance (common)shortness of breath (common)cannon a-waves in jugular venous

pulse (common)jugular venous distension (common)

Epidemiology

Impossible to give meaningful figures on incidence and prevalence.

In most young people bradycardia is physiological.

The incidence of pathological bradycardia rises with age as the underlying causes become more frequent.

DIAGNOSIS AND TESTElectrocardiogram (ECG or EKG)EchocardiogramBlood tests:

CBCUrine ExaminationLFT, Blood glucose.

Cont’ElectrolytesCreatinineCardiac enzymes (troponin),CK-MbABGChest X-ray

MANAGEMENT Stable patients:

12 lead EKGConsult cardiology

Unstable patients: CABsACLS -Bradycardia Algorithm

Address reversible causes (Hs & Ts)

AHA ACLS Adult Bradycardia Algorithm

Bradyarrhythmia typically seen when the HR <50/min

Is bradyarrhythmia causing the symptoms?

The priority should be identify and treat underlying causeMaintain patent airway: assist breathing if necessary.Apply oxygen ( if hypoxemic; Monitor pulse oxymetryApply cardiac monitor; monitor blood pressure.I/V access12 lead ECG. If available; do not delay treatment

Is the beadyarrhythmia causing:Hypotension?Altered mental status?Signs of suck?Ischemic chest pain?Acute heart failure?

Yes

No

Monitor and

observe

Give atropine If atropine in affective;Transcutaneous pacing (OR)Dopamine infusion (OR)Epinephrine infusion

ConsiderExpert consultationTranscutaneous pacing

Doses/detailsAtropine IV dose;First 0.5mg bolusRepeat every 3-5minutes; maximum 3mgDopamine IV infusion2-10mcg/kg/minuteEpinephrine IV infusion 2-10mcg/minute

Drug calculation

Dopamine

• Preparation : 200mg in 45 NS

• 1ml=4mg=4000mcg

• Dose: 5mcg – 20mcg/kg/min

• E.g. Body wt= 50kgs

• 5mcg x 50 x 60=15000

• 15000/4000= 3.75ml/hr

• (OR)

• Desired dose*body wt in kg*0.015=dose in ml

Epinephrine/Adrenaline

•Preparation: 2mg in 49ml D5

•Strength:

1ml=0.04mg=40mcg

•Dose: 0.2mcg-1.3mcg/kg/min

E.g.

0.2 x 50 x 60=600mcg

600/40=15m/hr

NURSING INTERVENTIONAccording to patient condition, do

planning, assessment, write nursing diagnosis and provide care.

General nursing interventionIf ineffective air way/unconscious;

 lateral recumbent or three-quarters prone position of the body (lateral sim’s position)

Suctioning,place air way

Cont’Monitor with pulse oxymeterGlasgow coma scaleCatheterization IV accessClose monitoring of vital signs (BP, pulse,

temperature, RR)Notify the concern physicianReassurance to patient /attendant

cont’

ECGPut patient on monitorMedication as per physician advisedInformed emergency laboratory, X-ray,

people if necessary.Assess the side affect of drugs.