Inter-relationships between hypertension, left ventricular hypertrophy and coronary heart disease.

Increased left ventricular mass predicts myocardial infarction: Recent studies have demonstrated that increased left ventricular mass is a more potent predictor than is elevated blood pressure of myocardial infarction or death due to coronary heart disease in hypertensive patients. Other research has shown that hypertensive patients commonly have episodes of asymptomatic ischemic ST-segment depression. Several different factors appear to account for this close relationship between myocardial muscle mass and the occurrence of ischemia and vascular morbid events. These include an increased resting demand for coronary blood flow (to supply the greater amount of myocardium), atherosclerotic obstruction of large coronary arteries and reduced vasodilatory capacity of the coronary microcirculation due to arteriolar hypertrophy and dysregulation, each of which reduces the capacity of the coronary circulation to increase its blood flow during stress (coronary reserve). Increased risk in population with more severe hypertension: Increased ventricular mass and coronary arteriolar abnormalities appear especially important as mechanisms of myocardial ischemia in populations with more severe hypertension, whereas conventional coronary disease predominates in patients with mild hypertension and multiple standard risk factors. Need for further research to optimize therapy: To develop optimal therapeutic approaches, further research is needed to clarify the basis of the inter-relationships between left ventricular hypertrophy and arterial abnormalities, to determine whether cardiac microvascular abnormalities parallel systemic hemodynamic patterns in hypertension and to ascertain the relative importance of reversing or preventing cardiovascular hypertrophy and myocardial ischemia for improving the prognosis of hypertensive patients.