Ventricular Rhythms - BMH/Tele
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Transcript of Ventricular Rhythms - BMH/Tele
VentricularVentricular RhythmsRhythms
Electrical impulses that originate from the ventricular conduction
system.
Ventricular RhythmsVentricular Rhythms
Bundle Branch Blocks (BBB) & Hemiblocks
Premature Ventricular Contractions (PVC)
Ventricular Escape Beat
Idioventricular Rhythm & AIVR
Ventricular Tachycardia
Ventricular Fibrillation
Ventricular Standstill
Asystole
Wide, Bizarre QRS’sSequential Depolarization
The electrical impulse originates from an ectopic site within one of the ventricles stimulating that side first, then depolarizes the other ventricle
Conduction time is slower than normal causing a wide, bizarre QRS complex
(> 0.12 sec)
Bundle Branch Block (BBB)Bundle Branch Block (BBB)
A bundle branch block refers to an obstruction in the transmission of the electrical impulse through
one branch (either right or left) of the bundle of His.
HemiblocksHemiblocks
A bundle branch block that occurs farther down the left bundle branch is called a hemiblock
Left Posterior Fascicular Block Left Anterior Fascicular Block
Bundle Branch Block (BBB)Bundle Branch Block (BBB)
In a bundle branch block, the impulse travels down the
unaffected bundle branch and then from one myocardial cell to the next to depolarize the
ventricle
Because this cell-to-cell conduction progresses much
more slowly than the conduction along the
specialized cells of the conduction system, ventricular
polarization is prolonged
Bundle Branch Block (BBB)Bundle Branch Block (BBB)
BBB: Analyzing a StripBBB: Analyzing a Strip
Rhythm: Regular
Rate: 60 – 100 bpm
P waves: Upright & uniform.
PRI: 0.12 – 0.20 sec
QRS: > 0.12 sec; notched or “bunny ears”.
***Interpretation: NSR w/ BBB & ST-segment depression
Premature Ventricular Premature Ventricular Contraction (PVC)Contraction (PVC)
A PVC is a premature, ectopic impulse that originates in either the right or left ventricle.
Electrical impulse originating from ventricle depolarizes only one ventricle at a time (resulting in sequential
depolarization).
This results in a wide, bizarre-looking QRS complex.
May be unifocal or multifocal.
PVC’sThe ST segment and T
wave slope in the opposite direction from
the main deflection of the QRS complex
If depolarization is abnormal, then
repolarization will be abnormal
Compensatory Pause
Occurs because the SA node isn’t depolarized by the ectopic ventricular beat, the discharge timing of the sinus
node remains unchanged and the underlying rhythm will resume on time
after the PVC
Unifocal PVC’s
Multifocal PVC’sMultifocal PVC’s
Patterned PVC’sBigeminy, Trigeminy, Quadrigeminy
Premature Ventricular Premature Ventricular Contraction (PVC)Contraction (PVC)
Causes:
Electrolyte ImbalancesHypokalemia, Hyperkalemia, Hypomagnesemia, Hypocalcemia
Metabolic Acidosis
Hypoxia
Myocardial Ischemia
Drug IntoxicationsCocaine, amphetamines, TCA’s
LV Enlargement
Increased Sympathetic Stimulation
Myocarditis
Premature Ventricular Premature Ventricular Contraction (PVC)Contraction (PVC)
Treatment:
If asymptomatic, no treatment may be required
Antiarrhythmics such as amiodarone (Cordarone), lidocaine, or procainamide
(Pronestyl), propafenone (Rythmol)
PVCs: Analyzing a Strip PVCs: Analyzing a Strip
Rhythm: Premature ectopic beat causes slight irregularity
Rate: Overall HR depends on rate of underlying rhythm
P waves: Ectopic beat is not preceded by a P wave.
PRI: None; impulse originates from a lower focus
QRS: Wide and bizarre; different from underlying QRS complexes. T wave is frequently in the opposite direction from
the QRS complex.
Run of PVC’sRun of PVC’s
3 or more consecutive PVC’s
Occurs within an underlying rhythm
Spontaneously resumes back to underlying
Symptomatic or Asymptomatic
Result of R-on-T Phenomenon
Amiodarone (Cordarone), lidocaine, or procainamide (Pronestyl)
Run of PVCs: Analyzing a Strip
Atrial Fibrillation (controlled) with a 5-beat run of PVCs (run of V-Tach or burst of PVCs) & ST-segment depression
Ventricular Escape BeatA ventricular beat that occurs as a result of a
pause in an underlying rhythm
Likely occur due to increased vagal effect on the SA node rather than because of
enhanced automaticity
A protective mechanism – preventing slow heart rates
Ventricular Escape Beat
How does this beat differ from a junctional escape beat???
Interpretation: NSR w/ ventricular escape beat following a pause converting back to NSR
Idioventricular (Escape) RhythmIdioventricular (Escape) Rhythm
Idioventricular (Escape) RhythmIdioventricular (Escape) Rhythm
Idioventricular rhythms occur when all pacemakers fail to function or when SV
impulses can’t reach the ventricles because of a block in the conduction
system
Idioventricular (Escape) RhythmIdioventricular (Escape) Rhythm
Causes:
Accompanied by Complete Heart Block
Myocardial Ischemia
MI
Digoxin Toxicity
Pacemaker Failure
Metabolic Imbalances
Idioventricular (Escape) RhythmIdioventricular (Escape) Rhythm
Treatment:
Pacemaker(Temporary – Permanent)
Treat Underlying Cause
IVR: Analyzing a StripIVR: Analyzing a Strip
Rhythm: Regular; can slow down as heart dies.
Rate: No atrial rate; ventricular rate 20 – 40 bpm
P waves: None; impulse originates from a lower focus
PRI: None; impulse originates from a lower focus
QRS: Wide and bizarre; equal to or > 0.12 sec. T wave not visible
Interpretation: Idioventricular Rhythm (IVR)
Accelerated Idioventricular Rhythm
Rate: 41 - 100
Wide, bizarre QRS complexes
No P waves
Accelerated Idioventricular Rhythm
How is AIVR distinguished from accelerated junctional rhythm???
Ventricular TachycardiasVentricular Tachycardias
Monomorphic, Polymorphic, Torsades de Pointes
Ventricular TachycardiaVentricular Tachycardia
Ventricular tachycardia usually results from increased myocardial irritability, which may be triggered
by enhanced automaticity or reentry within the Perkinje system or by
PVC’s initiating the R-on-T phenomenon
Ventricular TachycardiaVentricular TachycardiaCauses:
Myocardial ischemia
MI
CAD
Valvular heart disease
Heart failure
Cardiomyopathy
Electrolyte imbalances
Drug intoxication – digoxin, procainamide, quinidine, or cocaine
Ventricular Tachycardia
Non-sustained:
Paroxysmal bursts lasting less than 30 seconds
Sustained:
Stable, Unstable, or Pulseless
Ventricular TachycardiaVentricular Tachycardia
Three Types of ACLS Algorithms for V-Tach:
Stable Ventricular Tachycardia
Unstable Ventricular Tachycardia
Pulseless Ventricular Tachycardia
Monomorphic VT: Monomorphic VT: Analyzing a StripAnalyzing a Strip
Rhythm: Regular; sometimes slightly irregular
Rate: no atrial rate; ventricular rate 150 – 250 bpm
P waves: No P waves present
PRI: None
QRS: Wide and bizarre; Uniform; 0.12 sec.
T wave opposite direction of QRS
***Interpretation: Ventricular Tachycardia (VT)
Ventricular TachycardiaVentricular Tachycardia
A.K.A. – Monomorphic V-Tach
Polymorphic VT: Polymorphic VT: Analyzing a StripAnalyzing a Strip
Rhythm: Regular; sometimes slightly irregular
Rate: no atrial rate; ventricular rate 150 – 250 bpm
P waves: No P waves present
PRI: None
QRS: Wide and bizarre; Varied morphology; > 0.12 sec.
T wave opposite direction of QRS
***Interpretation: Polymorphic VT
Torsades de PointesTorsades de Pointes
Causes:
• Usually reversible
• Drugs that lengthen QT interval (amiodarone, ibultilide, erhythromycin, haloperidol, sotalol, levafloxicin)
• Myocardial ischemia
• Hypokalemia, hypomagnesemia, hypocalcemia
Torsades de PointesTorsades de Pointes
Treated by correcting the underlying cause:
Mechanical overdrive pacing
Magnesium sulfate
Electrical cardioversion
Torsades de Pointes: Torsades de Pointes: Analyzing a StripAnalyzing a Strip
Rhythm: Irregular; sometimes slightly irregular
Rate: no atrial rate; ventricular rate 150 – 250 bpm
P waves: No P waves present
PRI: None
QRS: Wide and bizarre; Varied morphology; > 0.12 sec.
T wave opposite direction of QRS
***Interpretation: Torsades de pointes
Ventricular Fibrillation (VF)Ventricular Fibrillation (VF)
A chaotic pattern of electrical activity in the ventricles in which electrical impulses arise from many different foci.
No effective myocardial contraction = No CO
Untreated V-fib causes most cases of sudden cardiac death in people outside of the hospital
Ventricular FibrillationVentricular FibrillationCauses:
Myocardial ischemia
MI
Untreated Ventricular Tachycardia
Underlying HD
Acid-Base Imbalance
Electric Shock
Severe Hypothermia
Electrolyte imbalancesHypokalemia, hyperkalemia, hypercalcemia
Ventricular Fibrillation
Fine or Coarse
VF: TreatmentVF: Treatment
Defibrillatory Shocks
CPR
Vasopressors
Antidysrhythmics
Determine Underlying Cause
DefibrillationDefibrillation
What Does Defibrillation Do?
The electrical current causes the myocardium to depolarize, which, in turn, encourages the SA node to resume normal control of the heart’s
electrical activity
RESETS THE ELECTRICAL CONDUCTION!
VF: Analyzing a StripVF: Analyzing a Strip
Rhythm: Chaotic
Rate: Cannot be determined; no discernible waves
P waves: No P waves
PRI: None
QRS: No discernible QRS complexes
***Interpretation: Ventricular Fibrillation (VF)
Ventricular Standstill SA node intact, so P waves are present
No ventricular conduction due to a preceding advanced AV block
AsystoleAsystole
NO ELECTRICAL ACTIVITY
NO MECHANICAL ACTIVITY
AsystoleAsystole
Treatment:
CPR
Epinephrine
Atropine
TIME TO WORKOUT!!!TIME TO WORKOUT!!!
ReferencesReferencesBeverage, D. Haworth, K., Labus, D. Mayer, B. H., & Munson, C.
(2005). ECG interpretation made incredibly easy, (3rd ed.). Ambler, PA: Lippincott, Williams, & Wilkins.
Chernecky, C., et al. (2002). Real world nursing survival guide: ECG’s & the heart. United States of America: W. B. Saunders Company.
Huff, J. (2006). ECG workout: Exercises in arrhythmia interpretation (5th ed.). United States of America: Lippincott, Williams & Wilkins.
Walraven, G. (1999). Basic arrhythmias (5th ed.). United States of America: Prentice-Hall, Inc.
www.madsci.com/manu/ekg_rhy.htm