This document discusses various types of ventricular conduction disorders and rhythms produced by conduction block. It describes ventricular extrasystoles which are caused by reentrant signaling or enhanced automaticity in some ectopic focus, leading to an enlarged QRS complex. Ventricular tachycardia is usually caused by reentry and seen after myocardial infarction. Atrioventricular block is a delay or failure in transmission of the cardiac impulse from atrium to ventricle and can be first, second or third degree. Premature contractions refer to non-sinus beats and include atrial and ventricular premature contractions which have various etiologies and presentations. Wolff-Parkinson-White syndrome is a condition in which the heart beats too fast

1. Ventricular ConductionVentricular Conduction
DisordersDisorders
vinay vermavinay verma
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2. Ventricular extrasystoles (VES)Ventricular extrasystoles (VES)
Is caused by either reentrant signaling orIs caused by either reentrant signaling or
enhanced automaticity in some ectopic focusenhanced automaticity in some ectopic focus
The QRS complex is enlarged (>120ms) andThe QRS complex is enlarged (>120ms) and
has different shapehas different shape

3. Coupling of VESCoupling of VES
Premature ventricular beats occurring after every normal beat arePremature ventricular beats occurring after every normal beat are
termed ventricular bigeminy, if 2 normal QRS complexes are follovedtermed ventricular bigeminy, if 2 normal QRS complexes are folloved
by VES, we speak of ventricular trigeminy.by VES, we speak of ventricular trigeminy.
Two VES grouped together are called a couplet, three a triplet. RunsTwo VES grouped together are called a couplet, three a triplet. Runs
longer than 3 VES is referred as ventricular tachycardialonger than 3 VES is referred as ventricular tachycardia

4. What is this arrhythmia?What is this arrhythmia?
Ventricular tachycardia
Ventricular tachycardia is usually caused by reentry, and most
commonly seen in patients following myocardial infarction.

5. Polymorphic ventricular tachycardiaPolymorphic ventricular tachycardia
– torsades de pointes– torsades de pointes
Is connected with prolonged QT interval.Is connected with prolonged QT interval.
The place of origin of the beats is moving – thatThe place of origin of the beats is moving – that
leads into different shape of QRSleads into different shape of QRS

6. Ventricular fibrillation (lethalVentricular fibrillation (lethal
condition)condition)

7. Conduction BlockConduction Block

8. Rhythms Produced by ConductionRhythms Produced by Conduction
BlockBlock
AV Block (relatively common)AV Block (relatively common)
– 11stst
degree AV blockdegree AV block
– Type 1 2Type 1 2ndnd
degree AV blockdegree AV block
– Type 2 2Type 2 2ndnd
degree AV blockdegree AV block
– 33rdrd
degree AV blockdegree AV block
SA Block (relatively rare)SA Block (relatively rare)

9. Atrioventricular BlockAtrioventricular Block
AV block is a delay or failure inAV block is a delay or failure in
transmission of the cardiac impulsetransmission of the cardiac impulse
from atrium to ventricle.from atrium to ventricle.
Etiology:Etiology:
Atherosclerotic heart disease;Atherosclerotic heart disease;
myocarditis; rheumatic fever;myocarditis; rheumatic fever;
cardiomyopathy; drug toxicity;cardiomyopathy; drug toxicity;
electrolyte disturbance, collagenelectrolyte disturbance, collagen
disease, lev’s disease.disease, lev’s disease.

10. 11stst
Degree AV BlockDegree AV Block
ECG Characteristics: Prolongation of the PR interval, which is constant
All P waves are conducted
The Alan E. Lindsay ECG Learning Center ; http://medstat.med.utah.edu/kw/ecg/

11. 22ndnd
Degree AV BlockDegree AV Block
Type 1
(Wenckebach)
EKG Characteristics: Progressive prolongation of the PR interval until a P
wave is not conducted.
As the PR interval prolongs, the RR interval actually
shortens
EKG Characteristics: Constant PR interval with intermittent failure to conduct
Type 2

12. 33rdrd
Degree (Complete) AV BlockDegree (Complete) AV Block
EKG Characteristics: No relationship between P waves and QRS complexes
Relatively constant PP intervals and RR intervals
Greater number of P waves than QRS complexes
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13. SA arrest with compensatory AV activitySA arrest with compensatory AV activity
When the activity of SA node is stopped, AV node takes over the role of
pacemaker.
Very similar type of arrhythmia is SA block: Pacing in SA node is generated, but
not conducted to the myocardium+

14. Intraventricular BlockIntraventricular Block
Intraventricular conduction system:Intraventricular conduction system:
1.1. Right bundle branchRight bundle branch
2.2. Left bundle branchLeft bundle branch
3.3. Left anterior fascicularLeft anterior fascicular
4.4. Left posterior fascicularLeft posterior fascicular

15. Intraventricular BlockIntraventricular Block
Etiology:Etiology:
Myocarditis, valve disease,Myocarditis, valve disease,
cardiomyopathy, CAD, hypertension,cardiomyopathy, CAD, hypertension,
pulmonary heart disease, drug toxicity,pulmonary heart disease, drug toxicity,
Lenegre disease, Lev’s disease et al.Lenegre disease, Lev’s disease et al.
Manifestation:Manifestation:
Single fascicular or bifascicular blockSingle fascicular or bifascicular block
is asymptom; tri-fascicular block mayis asymptom; tri-fascicular block may
have dizziness; palpitation, syncopehave dizziness; palpitation, syncope
and Adams-stokes syndromeand Adams-stokes syndrome

16. Premature contractionsPremature contractions
The term “premature contractions”The term “premature contractions”
are used to describe non sinus beats.are used to describe non sinus beats.
Common arrhythmiaCommon arrhythmia
The morbidity rate is 3-5%The morbidity rate is 3-5%

17. Atrial premature contractionsAtrial premature contractions
(APCs)(APCs)
APCs arising from somewhere in either theAPCs arising from somewhere in either the
left or the right atrium.left or the right atrium.
Causes:Causes: rheumatic heart disease, CAD,rheumatic heart disease, CAD,
hypertension, hyperthyroidism,hypertension, hyperthyroidism,
hypokalemiahypokalemia
Symptoms:Symptoms: many patients have nomany patients have no
symptom, some have palpitation, chestsymptom, some have palpitation, chest
incomfortable.incomfortable.
Therapy:Therapy: Needn’t therapy in the patientsNeedn’t therapy in the patients
without heart disease. Can be treated withwithout heart disease. Can be treated with
ß-blocker, propafenone, moricizine orß-blocker, propafenone, moricizine or
verapamil.verapamil.

18. Ventricular PrematureVentricular Premature
Contractions (VPCs)Contractions (VPCs)
Etiology:Etiology:
1.1. Occur in normal personOccur in normal person
2.2. Myocarditis, CAD, valve heartMyocarditis, CAD, valve heart
disease, hyperthyroidism, Drugdisease, hyperthyroidism, Drug
toxicity (digoxin, quinidine and anti-toxicity (digoxin, quinidine and anti-
anxiety drug)anxiety drug)
3.3. electrolyte disturbance, anxiety,electrolyte disturbance, anxiety,
drinking,drinking, coffeecoffee

19. Pre-excitation syndromePre-excitation syndrome
(W-P-W syndrome)(W-P-W syndrome)
There are several type of accessoryThere are several type of accessory
pathwaypathway
1.1. Kent: adjacent atrial and ventricularKent: adjacent atrial and ventricular
2.2. James: adjacent atrial and hisJames: adjacent atrial and his
bundlebundle
3.3. Mahaim: adjacent lower part of theMahaim: adjacent lower part of the
AVN and ventricularAVN and ventricular
Usually no structure heart disease,Usually no structure heart disease,
occur in any age individualoccur in any age individual

20. WPW syndromeWPW syndrome
Manifestation:Manifestation:
Palpitation, syncope, dizzinessPalpitation, syncope, dizziness
Arrhythmia: 80% tachycardia isArrhythmia: 80% tachycardia is
AVRT, 15-30% is AFi, 5% is AF,AVRT, 15-30% is AFi, 5% is AF,
May induce ventricular fibrillationMay induce ventricular fibrillation

21. Wolff-Parkinson White Syndrome (WPW)Wolff-Parkinson White Syndrome (WPW) is a conditionis a condition
in which the heart beats too fast due to abnormal, extrain which the heart beats too fast due to abnormal, extra
electrical pathways between the heart’selectrical pathways between the heart’s atriumatrium andand
ventriculumventriculum ..

22. Thank you for your attentionThank you for your attention