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[Post-infarct ventricular tachycardia. Electrophysiological aspects, endocardial and epicardial electromapping and
Abstract:
Seven patients (6 men and 1 woman), aged 45-67 years, with previous myocardial infarction and recurrent sustained ventricular tachycardia (VT), refractory to medical treatment, underwent encircling endocardial ventriculotomy, according to a modified Guiraudon's technique, associated with surgical resection of ventricular aneurysm. Before surgery all patients underwent electrophysiologic study, to evaluate the modalities of onset and interruption of VT; endocardial mapping at multiple sites was carried out in order to define the site of origin of VT and the sequence of endocardial activation: during VT in 5/5 patients the earliest activation occurred in the left ventricle at mid septum (2 cases), in the low (1 case) and high (1 case) septal regions and in the latero-basal region (1 case); the arrhythmias always originated at the border between fibrous and viable tissue. Intraoperative mapping was carried out from 18-29 points of the epicardial surface, both in sinus rhythm (7 cases) and during VT in the 6 patients in whom the arrhythmia was inducible with electrical stimulation. During sinus rhythm fragmented electrical activity of low voltage and prolonged duration was recorded from the epicardial surface of the aneurysm in all cases; during VT the site of earliest activation was localized in the low posterior (3 cases), high lateral (2 cases) and high posterior (1 case) regions of the left ventricle. Intraoperative endocardial mapping during VT confirmed the site of origin of the arrhythmia, as determined by preoperative mapping, in the 3 cases in whom it was performed. In all cases encircling endocardial ventriculotomy around the area of earliest activation or, when the origin of VT was not precisely determined, along the border zone of the aneurysm, was associated with conventional surgical procedures (aneurysmectomy: 6 cases; incision-suture: 1 case; aorto-coronary bypass: 1 case; mitral valve replacement: 1 case). One patient died in the early post-operative course with a low-output syndrome. During a follow-up of 6-35 months, one patient died two months after surgery because of intractable heart failure; the remaining patients are alive and well, with no recurrence of VT; none of them required antiarrhythmic therapy.(ABSTRACT TRUNCATED AT 400 WORDS)