Elsevier

American Heart Journal

Volume 94, Issue 5, November 1977, Pages 603-610
American Heart Journal

The role of local disparity in conduction and recovery time on ventricular vulnerability to fibrillation**

https://doi.org/10.1016/S0002-8703(77)80130-0Get rights and content

Summary

In experiments on 16 mongrel dogs, conduction time (CT), local refractory periods (RP), and recovery time (RT) of conducted beats were measured in the ventricles under local coronary perfusion and under systemic intravenous infusion with potassium chloride or epinephrine. The values of these parameters found in the locally perfused and in the non-perfused areas and the degree of local dispersion of these values were correlated with ventricular fibrillation thresholds. Regardless of potassium or epinephrine infusion, ventricular vulnerability to fibrillation was significantly lower with local infusions than with systemic infusions. It was found that changes of CT, RP, and RT in either direction would occur with increased and decreased fibrillation thresholds, and they were not directly correlated to ventricular vulnerability to fibrillation. The local dispersion of these parameters between the perfused and non-perfused areas, however, was always increased when ventricular vulnerability was high, and decreased when ventricular vulnerability was low. These results are strong evidence supporting the importance of local dispersion in excitability. The local dispersion was best represented by local variation in the RT of conducted beats, which under all experimental conditions correlated best with ventricular vulnerability. The other electrophysiological parameters seem to be of importance for the ventricular vulnerability when they contribute to an increased or decreased local dispersion of excitability.

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**

Supported by Contract N01-HV-22974 and Grant HL-18796 from the National Institutes of Health.

*

Dr. Merx was a visiting scientist from the Department of Internal Medicine, North Rhine-Westphalia Technical University, Aachen, West Germany, and was supported by a grant from the German Research Association.

1

From the Department of Medicine (Cardiology), Albany Medical College of Union University, and the Electrocardiography Laboratory, Albany Medical Center Hospital, Albany, N. Y.

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