Echocardiographic Assessment and Systolic Time Interval Measurements in the Evaluation of Severe Hypertension in Nigerian Africans*

Echocardiograms, systolic time interval measurements and electrocardiograms were obtained before treatment of 15 Nigerian patients with severe hypertension (WHO stage 2) but without overt heart failure. These were compared with the measurements in 12 normotensive controls. In the hypertensive subjects, left ventricular (LV) posterior wall thickness septal thickness, relative wall thickness and LV wall mass were greater than normal (p less than 0.01 respectively). However, the LV cavity size was within the normal range. The increase in LV wall mass correlated positively with the increase in mean blood pressure (r = 0.96, P less than 0.001). The ejection fraction (EF) and mean velocity of circumferential fibre shortening (mVcF) were decreased (P less than 0.01, P less than 0.05) respectively, while the calculated systemic vascular resistance (SVR) was elevated (p less than 0.01). THe pre-ejection period (PEP) was prolonged, but left ventricular ejective time (LVET) was shortened and therefore PEP/LVET was increased. Electrocardiographic criteria did not detect left ventricular hypertrophy in four out of the 15 hypertensive patients, all of whom had left ventricular hypertrophy by echocardiography. These findings are similar to the abnormalities described for non-African hypertensive patients; and show that hypertension causes LV dysfunction before the onset of overt heart failure.