Author + information
- Received August 20, 1985
- Revision received October 30, 1985
- Accepted November 13, 1985
- Published online April 1, 1986.
- Hrayr S. Karagueuzian, PhDa,
- Kaoru Sugi, MD,
- Masao Ohta, MD,
- Michael C. Fishbein, MD, FACC,
- William J. Mandel, MD, FACC and
- Thomas Peter, MD, FACC
- ↵aAddress for reprints: Hrayr S. Karagueuzian, PhD, Division of Cardiology, Room 5314, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, California 90048.
The susceptibility of infarcted right ventricular myocardium to inducible ventricular tachyarrhythmias was serially evaluated in 18 conscious dogs during the first 2 weeks after permanent right coronary artery occlusion. Properly timed double premature stimuli applied to the right ventricular outflow tract induced sustained (longer than 1 minute) ventricular tachycardia at rates of 190 to 400 beats/min in nine dogs, and ventricular fibrillation in six dogs. No ventricular arrhythmias could be induced in the remaining three dogs. The zone of premllture coupling intervals within which ventricular tachyarrhythmias could be induced decreased in each dog as the infarct aged, and by day 12 after occlusion, no ventricular Ilrrhythmias couJd be induced in any of the dogs studied. Both the size and the degree of patchiness (graded from 0 for no patchiness to + 4 for patchiness throughout the infarct) of the infarct appear to be related to the nature of the induced rhythm. Infarcts with greater heterogeneity and those that were larger than 8% of the right ventricular volume were associated with a higher incidence of ventr.cular fibrillation, and infarcts with a lesser degree of patchiness were more suitable for sustained ventricular tachycardia (3.4 ± 1.2 versus 1.4 ± 0.4, p < 0.05).
These findings indicate that 1) the infarcted right ventricular myocardium, independent of left ventricular involvement, can be associated with malignant ventricular tachyarrhythmias, 2) ventricular tachyarrhythmias can be induced only during a well defined postinfarction period; and 3) both the size and geometry of the right ventricular infarct determine the nature of the induced ventricular rhythm.
with the technical assistance of Avile McCullen
This study was supported in part by Grant 731-G2-1 from the American Heart Association, Greater Los Angeles Affiliate, and by ECHO Research Fund, Cedars-Sinai Medical Center. Dr. Karagueuzian is the recipient of Research Career Development Award 01293-02 from the National Heart, Lung and Blood Institute, Bethesda, Maryland. Presented in part at the 55th Scientific Sessions of the American Heart Association, Dallas, Texas, November 1982.
- Received August 20, 1985.
- Revision received October 30, 1985.
- Accepted November 13, 1985.
- American College of Cardiology Foundation