Alterations in left ventricular wall stress and coronary circulation in patients with isolated systolic hypertension

Abstract

Objectives: To study the alterations in cardiac function and coronary circulation in patients with isolated systolic hypertension (ISH).

Patients: Ten patients with a history of ISH were studied and findings were compared with those of seven normotensive subjects. All of the patients had angiographically normal coronary arteries. They underwent cardiac catheterization, and haemodynamic variables and coronary flow velocity were measured. All of the patients also underwent treadmill exercise testing.

Main outcome measures: Left ventricular mass was evaluated by echocardiography. The coronary flow velocity data were obtained by using the intracoronary Doppler catheter technique. ST-segment depression was observed on the exercise electrocardiogram.

Results: Systemic vascular resistance did not differ, whereas total arterial compliance was decreased in the ISH patients versus the controls (P < 0.001). The left ventricular mass of the ISH patients was increased slightly, but their left ventricular systolic wall stress was greater than that of the controls (P < 0.01). The coronary flow reserve ratio and the ratio of diastolic to total coronary flow were decreased in the ISH patients versus the controls (P < 0.01). ST-segment depression on the exercise electrocardiogram was frequently observed in the hypertensive patients (80 versus 0% in control subjects, P < 0.01).

Conclusions: Patients with ISH were characterized haemodynamically by a decrease in arterial compliance. They showed an increase in left ventricular systolic wall stress and also showed decreases in coronary flow reserve ratio and in the relative diastolic coronary flow. Such alterations observed in patients with ISH are detrimental to the heart and may contribute to a reduced exercise capacity and the induction of subendocardial ischaemia during exercise.