Echocardiograms were performed on 105 male participants in the National Institutes on Aging's volunteer Longitudinal Study Program. All subjects (25--84 years of age) were physically active and had no evidence of hypertension or cardiovascular disease. Measurements were made of the initial diastolic (E-F) slope of the anterior mitral valve leaflet, the aortic and left ventricular cavity dimensions, and the thickness of the posterior left ventricular wall. Fractional shortening of the minor semi-axis of the left ventricle and the velocity of circumferential fiber shortening were also determined. It was found that increasing age correlated with a decrease mitral valve E-F slope and increased aortic root diameter and left ventricular wall thickness. Aging did not affect left ventricular cavity dimension, fractional shortening of the minor semi-axis, and velocity of circumferential fiber shortening. These findings suggest that aging in the normal male is associated with altered left ventricular diastolic filling, increased aortic root diameter and left ventricle hypertrophy but little change in contractile ability in the resting state.

Using echocardiography, we identified 21 patients with a syndrome that included severe concentric cardiac hypertrophy, a small left ventricular cavity, and supernormal indexes of systolic function without concurrent medical illness or ischemic heart disease. Thirteen of the patients presented with dyspnea or chest pain. All patients studied had a history of hypertension and were compared with normotensive controls matched for age and sex. The patients were elderly (mean age, 73.3 years), predominantly female (16 patients), and mostly black (15 patients). Their cardiac function was characterized by excessive left ventricular emptying (ejection fraction on two-dimensional echocardiography [patients vs. controls], 79 +/- 4 vs. 59 +/- 5 per cent, P less than 0.001) and abnormal diastolic function as manifested by a prolonged early diastolic filling period (279 +/- 25 vs. 160 +/- 45 msec, P less than 0.001) and reduced peak diastolic dimension increase (11 +/- 4 vs. 16 +/- 5 cm per second, P less than 0.05). In spite of the clinical presentation of heart failure, all of 9 patients receiving either beta-receptor antagonists or calcium-channel blocking agents obtained symptomatic relief, whereas 6 of 12 patients receiving vasodilator medications had severe hypotensive reactions, including one death. We conclude that this unique subset of hypertensive patients has a clinical syndrome that warrants recognition and tailored management.

Radioactive microspheres were used to estimate the changes in regional myocardial blood flow occurring during acute myocardial ischemia. Carbonized 15-fj, spheres were injected into the left atrium of 28 open-chest dogs and the radioactivity of selected areas determined after sacrifice. Acute occlusion of the left circumflex coronary artery produced a significant diminution in the proportion of microspheres reaching the circumflex area. In addition, there was a disproportionate decrease in endocardial radioactivity in the ischemic area (endocardial/epicardial radioactivity ratio falling from 1.17 to 0.76, P < 0.001) but not in the nonischemic area. Both nitroglycerin (0.4 mg) and propranolol (1 mg/kg) failed to cause a significant change in the ratio of circumflex to descendens radioactivity during ischemia. They did, however, cause a significant increase in the ratio of endocardial to epicardial radioactivity in both ischemic and nonischemic areas.KEY WORDS nitroglycerin acute coronary artery occlusion collateral flow endocardial/epicardial flow propranolol regional myocardial blood flow• Radioactive microspheres have been used in experimental animals to estimate regional myocardial blood flow (1, 2). This technique has the advantage over previous methods in that multiple determinations can be made in the same animal, thereby allowing each to serve as its own control. In the present investigation the distribution of radioactive microspheres was determined during acute coronary artery occlusion in anesthetized dogs. These studies suggest that within an ischemic area of myocardium, there is a disproportionate subendocardial ischemia. During acute coronary artery occlusion nitroglycerin and propranolol were found to

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