Programmed electrical stimulation-induced arrhythmias in isolated hearts from adult and senescent rats

In isolated hearts from normal rats, we previously demonstrated an age-related increase of spontaneous ventricular arrhythmias. The aim of the present experiments was to test the possible effect of aging on ventricular arrhythmias induced by programmed electrical stimulation. Experiments were performed in isolated cardiac preparations of 6- and 24-month-old normal Wistar rat hearts. Programmed electrical stimulation (single or double premature stimuli following a stimuli train) was tested in isolated Langendorff perfused hearts during control perfusion, after left anterior descending coronary artery ligature and during global hypoxia. No significant differences were observed between adult and senescent hearts in the incidence of programmed electrical stimulation-induced ventricular arrhythmias during these three different situations. These experiments demonstrate that the cardiac "physiological" aging process is not associated with a greater propensity to programmed electrical stimulation-induced arrhythmias.