Ventricular Postextrasystolic Potentiation in the Dog A Study Using List Mode Radionuclide Ventriculography

Abstract

The first and second postextrasystolic sinus beats (PESB) were isolated and analyzed in five open-chested dogs with the aid of list mode radionuclide ventriculography. Ventricular stimulation was delivered using a coupling interval of 150 msec from electrodes positioned at two (in two animals) or five (in three animals) different ventricular sites. There were marked increases in both left ventricular ejection fraction (41.5 ± 4% vs. 56.8 ± 3.9%; control vs. PESB, p