Long term electrophysiological abnormalities resulting from experimental myocardial infarction in cats

R. J. Myerburg, Henry Gelband, K. Nilsson, R. J. Sung, R. J. Thurer, A. R. Morales, A. L. Bassett

Research output: Contribution to journalArticlepeer-review

65 Scopus citations


Chronic electrophysiological abnormalities in cats surviving experimental myocardial infarction (MI) were recorded 1 week to 6 months following single-stage ligation of multiple distal tributaries of the left coronary artery system. Sixteen of 32 long-term MI cats (50%) had a propensity to ventricular ectopic activity (VEA), as established by at least one of three criteria : (1) spontaneous VEA on electrocardiogram (ECG) prior to death (8 of 32 cats; 25%); (2) accelerated ventricular escape rhythms during vagal stimulation (7 of 21; 33%); and (3) rapid automatic activity of the isolated left ventricle in tissue bath (11 of 32; 34%). Cellular electrophysiological abnormalities in surviving subendocardial tissue overlying the MI scar were recorded in 29 of 32 preparations (91%). Focal areas of action potential (AP) abnormalities were interspersed between areas of normal activity. AP abnormalities were of three types: (1) prolongation of AP duration; (2) shortening of AP duration; and (3) low amplitude action potentials. Type 1 abnormalities were recorded most commonly between 1 week and 1 month after MI, and rarely were recorded later. Type 2 abnormalities began to appear 1 1/2 months after MI and were most common at 3-6 months. Type 3 abnormalities were recorded at any stage. At 3 months after MI and beyond, surviving cells were histologically normal, despite continued AP abnormalities and propensity to VEA. The data demonstrate a persistence of deranged cellular electrophysiology for up to 6 months after MI.

Original languageEnglish (US)
Pages (from-to)73-84
Number of pages12
JournalUnknown Journal
Issue number1
StatePublished - 1977

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine


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