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

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Abstract
Echocardiograms, systolic time interval measurements and ECG 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 < 0.01, respectively). 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 < 0.001). The ejection fraction (EF) and mean velocity of circumferential fiber shortening (mVcF) were decreased (P < 0.01, P < 0.05, respectively), while the calculated systemic vascular resistance (SVR) was elevated (P < 0.01). The pre-ejection period (PEP) was prolonged, but LV ejective time (LVET) was shortened and therefore PEP/LVET was increased. ECG criteria did not detect LV hypertrophy in 4 of the 15 hypertensive patients, all of whom had LV 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.