The effects of sustained preload reduction have been demonstrated for several nitrates but not for erythrityl tetranitrate. In seven patients with coronary heart disease, a randomized double-blind crossover clinical trial showed that chewable erythrityl tetranitrate, 10 mg, produced significant changes in systolic time intervals consistent with preload reduction and lasting for at least four hours. As compared with placebo, ejection time index (ETI) fell and remained significantly low between 6 and 90 minutes after administration, and pre-ejection period (PEP), isovolumic contraction time (IVCT), and pre-ejection period/left ventricular ejection time (PEP/LVET) rose and remained significantly increased between 22 minutes and the four-hour endpoint. We conclude that erythrityl those dying in the institution. The causes of death among those with intraventricular conduction disturbances were similar to those of comparable age and sex without these conditions. Sudden death among those with second and third degree heart block was due in the majority of cases to other cardiac conditions, such as acute myocardial infarction and acute pulmonary embolization. It was concluded that the presence of an intraventricular conduction disturbance in the aged, uncomplicated by the development of second or third degree heart block, is not an indication for the insertion of a cardiac pacemaker in the aged.