Ventricular tachycardia in healing canine myocardial infarction: Evidence for multiple reentrant mechanisms

Nabil Kanaan, Nikki Robinson, Sandford I. Roth, Dingzhong Ye, Jeffrey Goldberger, Alan Kadish

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

Prior studies have demonstrated that unimorphic VT, sometimes due to epicardial reentry, can be induced in healing canine MI; however, the characterization of the types of reentry involved has differed among prior studies. The purpose of this study was to further characterize the spectrum of epicardial reentrant circuits during induced VT in experimental canine MI. Experimental MI was created by total occlusion of the LAD in dogs. Five days later, programmed stimulation was used to induce VT, which was mapped on the epicardium using a combination of vector and isochronal techniques. Pathological analysis was used to determine regions of transmural MI. Epicardial reentrant circuits were identified in eight dogs. The mean cycle length of induced VT was 212 ± 32 ms. In 3 of 8 experiments, a region of transmural MI was present, which formed at least a portion of o central zone of block around which reentrant impulses circulated. In five experiments, reentry was functional in nature, although the characteristics of the region of functional conduction block were variable. Long lines o f functional block, short lines of block with slow conduction transverse to fiber orientation, and leading circle reentry were each observed in different experiments. Although a zone of slow conduction was identified in seven of the experiments, slow conduction transverse to fiber orientation appeared crucial in maintaining reentry in only three experiments. Multiple reentrant mechanisms of VT may be present in this single canine infarction model. Although a zone of slow conduction is usually present, the characteristics of the region of block are highly variable. However, epicardial reentry accounted for only a minority of induced arrhythmia episodes.

Original languageEnglish (US)
Pages (from-to)245-260
Number of pages16
JournalPACE - Pacing and Clinical Electrophysiology
Volume20
Issue number2 I
DOIs
StatePublished - Mar 11 1997
Externally publishedYes

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Keywords

  • anisotropic reentry
  • slow conduction
  • vector mapping
  • ventricular tachycardia

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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