Phase 1B ventricular arrhythmia in the dog: localized reentry within the mid-myocardium.

Abstract

Intramural and epicardial composite electrograms, signal-averaged orthogonal bipolar electrograms across the ischemic zone, and closely-spaced bipolar electrograms from subendocardium, mid-myocardium, and subepicardium were utilized to determine if phase 1B reentry resulted from localized reentry within ischemic mid-myocardium. During the first 10 minutes following coronary ligation, activation delays were largest in ischemic subepicardium, with continuous electrical activity in ischemic epicardium linking a ventricular extrasystole to the preceding beat. During the 15-30 minute period, activation delay observed in ischemic mid-myocardium exceeded activation delay on the epicardial surface. Ventricular extrasystoles were associated with mid-myocardial delays > 130 msec. With short-coupled extrasystoles (< 300 msec), electrical activity in ischemic mid-myocardium linked an extrasystole with the preceding beat. Although single extrasystoles with coupling intervals > 300 msec were also associated with mid-myocardial delays > 130 msec, most extrasystoles (68%) demonstrated an isoelectric gap > 20 msec. The data demonstrate an association between delayed activation within ischemic mid-myocardium and phase 1B arrhythmia resulting from (1) localized reentry in ischemic mid-myocardium and (2) a delay-dependent "non-reentrant" mechanism.

• Authors: E Patterson, M Kalcich, B J Scherlag
• Journal: Journal of interventional cardiac electrophysiology : an international journal of arrhythmias and pacing (J Interv Card Electrophysiol) Vol. 2 Issue 2 Pg. 145-61 (Jun 1998) ISSN: 1383-875X [Print] Netherlands
• PMID: 9870007 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.)

Topics

• Animals
• Arrhythmias, Cardiac (etiology, physiopathology)
• Atrioventricular Node (physiopathology)
• Bundle of His (physiopathology)
• Dogs
• Electrocardiography
• Endocardium (physiopathology)
• Heart Block (physiopathology)
• Heart Rate (physiology)
• Myocardial Ischemia (complications)
• Pericardium (physiopathology)
• Tachycardia, Ventricular (etiology, physiopathology)
• Time Factors
• Vagus Nerve (physiopathology)
• Ventricular Dysfunction (etiology, physiopathology)
• Ventricular Fibrillation (etiology, physiopathology)
• Ventricular Premature Complexes (etiology)