Response of the left ventricle in coronary artery disease to postextrasystolic potentiation.

Left ventricular volumes and contractile patterns were evaluated during the first sinus beat after a compensatory pause resulting from ventricular arrhythmia and were compared to the second sinus beat (control beat) in order to evaluate the effect of postextrasystolic potentiation. Twelve patients had no evidence of heart disease (group I). Fifty patients had coronary artery disease and included 14 patients (group IIa) with no prior myocardial infarction and a normal left ventricular contractile pattern and 19 pateints (group IIb) with an abnormal contractile pattern. Seventeen pateints (group IIc) had a documented transmural myocardial infarction as well as an abnormal left ventricular contractile pattern. In all patients the first postextrasystolic sinus beat, when compared to the second sinus beat, demonstrated increases in stroke volume and ejection fraction and decrease in end-systolic volume. There were no qualitative changes in the contractile pattern in the immediate postextrasystolic beat in the ...