Josephson Clinical Cardiac Electrophysiology

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Chapter 6: Ectopic Rhythms and Premature Depolarizations ■

FIGURE 6.22 Fascicular depolarization–induced PMVT/VF. In the left panel, a surface electrocardiogram (ECG) recording from a young patient without structural or electrical heart disease who had resuscitated cardiac arrest. The initial “trigger” beat has a left bundle (late transition) left superior morphology, suggesting a moderator band or RV papillary muscle site of origin. The right panel shows an intracardiac echocardiography image of the mapping catheter positioned on the moderator band. Purkinje signals during these trigger beats were activated − 20 msec before QRS onset. Ablation of the moderator band prevented subsequent VF episodes. PMVT, polymorphic ventricular tachycardia; RV, right ventricle; VF, ventricular fibrillation. (Courtesy of Ramanan Kumareswaran, MD.)

APD

VPD

1

2

V1

A

A

A

A

A p

A p

HRA

A

A

A

A

A p

A p

CS

V

V

V

V

A V

A

A

V

H

A p

H

H

H

A H

A

HBE

p

T

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FIGURE 6.23 Differentiation of ventricular premature depolarization (VPD) from an atrial premature depolarization (APD) with aberration. The third and fifth ventricular complexes both manifest a right bundle branch block pattern. The former is demonstrated to be a VPD (arrow) because of the absence of a preceding His bundle deflection. The latter is aberrantly conducted (APD, arrow) from the second of two atrial premature depolarizations (Ap), which is not seen on the surface electrocardiogram (ECG) (there is no clear P wave noted during the second Ap). Aberration is confirmed by a His bundle deflection preceding the QRS complex, which, in this case, is associated with H-V prolongation. The fact that clear His bundle deflections are recorded before and after the VPD rules out the improper position of the catheter as the cause of failure to record a His bundle spike with the VPD. CS, coronary sinus; HBE, His bundle electrogram; HRA, high right atrium; T, time line.