[Coronary reserve of the hypertensive heart: relationship to left ventricular hypertrophy]

We investigated the relationship between electrocardiographic left ventricular hypertrophy with ST-changes, and coronary circulation and myocardial metabolism in 25 patients with essential hypertension (systolic blood pressure greater than or equal to 160 mmHg, diastolic blood pressure greater than or equal to 95 mmHg). No patients had abnormal coronary arteriograms. They were categorized in two groups: non-hypertrophy group; cases with no hypertrophy on echocardiograms (interventricular septum and posterior wall thickness less than or equal to 11 mm), and hypertrophy group; cases with hypertrophy (wall thickness greater than or equal to 12 mm). Supine bicycle ergometry (50 watts, 50 rpm, 15 min) was performed during coronary sinus catheterization and electrocardiography. For cardiac hemodynamics, the coronary circulation and myocardial metabolism were observed at rest and during exercise. There was no significant difference in unit coronary blood flow (coronary blood flow per 100 gm) before exercise between the two groups. Unit coronary blood flow was significantly greater in the non-hypertrophy group after exercise. However, total coronary blood flow (coronary blood flow per 100 gm x left ventricular mass) showed no significant difference between the two groups. Coronary vascular resistance per 100 gm was higher in the hypertrophy group during exercise, though there was no significant difference at rest. Myocardial oxygen extraction O2 (A-C) was not different between the two groups at rest and during exercise, but unit myocardial oxygen consumption (MVO2) during exercise was higher in the non-hypertrophy group than in the hypertrophy group. The lactate extraction ratio tended to decrease in the hypertrophy group during exercise, and tended to increase in the non-hypertrophy group. Myocardial potassium flux tended to increase in the hypertrophy group during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)