Does it take more energy for the cardiac ventricles to contract or to relax? And if it takes more energy for the ventricles to relax than to contract, would it be reasonable to believe that we die in ventricular systole rather than in ventricular diastole?
Two observations suggest that we die in ventricular systole. One, as illustrated in the accompanying Figures 1 to 5 , if the minute size of the left ventricular cavity represents ventricular diastole, what size could possibly represent ventricular systole? Two, the thickness of the left ventricular free wall at necropsy corresponds to the thickness measured during life by echocardiogram during ventricular systole, not during ventricular diastole.
Cross sections of the cardiac ventricles cut parallel to the posterior atrioventricular sulcus in a 76-year-old hypertensive woman who died suddenly after hospitalization for what turned out to be acute aortic dissection. There was a through-and-through tear in the ascending aorta leading to hemopericardium. The heart weighed 310 g. The left ventricular cavity is minute.
Cross section of the cardiac ventricles in a 69-year-old obese, hypertensive woman who died of an ischemic bowel after a recent stroke. The heart weighed 515 g, and she weighed 250 lb. The sections of cardiac ventricles show a minute left ventricular cavity. The heart floated in water due to the excessive subepicardial adipose tissue (body mass index 39 kg/m 2 ).
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