Arrhythmogenic age-related effects of lysophosphatidylcholine in the rat heart

Ventricular arrhythmias are the most common cause of death among patients with coronary artery disease; this is more evident in the elderly, who tend to have more severe coronary artery disease and age-dependent modifications of cardiac electrophysiology. Lysophosphoglycerides, which accumulate in the ischemic myocardium, are responsible for oscillatory after-potentials and may contribute to the development of ventricular arrhythmias. The aim of this study was to examine the effects of lysophosphatidylcholine (5 x 10(-5) M) in the absence or presence of epinephrine (10(-6) M) in isolated, perfused hearts from adult (6-12 months old) and senescent (24 months old) rats. Rat hearts (30/group) were randomly divided into four groups each of which included hearts of 6, 12 and 24-month old rats. The groups comprised a control group, a group treated with epinephrine, a group treated with lysophosphatidylcholine and a group treated with both epinephrine and lysophosphatidylcholine. Analysis of arrhythmias indicated a linear correlation between epinephrine- and lysophosphatidylcholine-induced ventricular arrhythmias and age. The incidence of arrhythmias was higher in the hearts treated with epinephrine and lysophosphatidylcholine together than in those treated with either substance separately (p less than 0.01). The results indicate that age influences the arrhythmogenic action of lysophosphatidylcholine, and that epinephrine contributes to this effect.