Verapamil-Sensitive Ventricular Tachycardia

Report:

Ventricular tachycardia 152/min

Comment:

This arrhythmia resisted flecainide, sotalol, digoxin and adenosine; verapamil slowed the rate significantly (Fig 82a) and allowed partial sinus captures, but could not abolish it. The cardioversion was effected by 200 Joule countershock day after admission.

The morphology of the tachycardia is similar to that of RBBB + LAHB. The qR complex in V1 suggests ventricular ectopic origin, as does the suggestion of independent atrial activity (AV dissociation). The latter is more easily observed in the post-verapamil traces, with slower ventricular rate. In the rhythm strip, sinus capture fusion beats prove the ventricular origin of the tachycardia. The strip also shows rSR’ pattern in its lead (MCL1) with broad S wave not seen in RBBB (or in the preceding Case 81 with impeccable RBBB morphology).

Most verapamil-sensitive fascicular tachycardias have, like this example, RBBB + LAHB pattern; a few have been reported with RBBB + LPHB one. In one series, 31% of (32) patients, all with normal hearts, had LBBB pattern VT84. Approximately 50% of all paroxysms could be terminated by adenosine as well as verapamil.[! XE "Fascicular tachycardias" \t "See Ventricular tachycardia:fascicular" !]

82a. Sinus capture beats have long PR intervals.

82b. Sinus rhythm post-cardioversion. The inverted T waves could be ascribed to the post-tachycardia “syndrome”. The embryonic R’ waves in V1 have no significance. 83. 81 year old man in pulmonary œdema.