ENDOCARDIAL VERSUS MIDWALL MEASUREMENT OF LEFT-VENTRICULAR FUNCTION IN MILD HYPERTENSION - AN INSIGHT FROM THE HARVEST STUDY

Objective To compare endocardial and midwall measurement of left ventr icular fractional shortening in assessing cardiac systolic function in hypertension. Setting Seventeen hypertension clinics in northeast Ita ly. Main outcome measures Left ventricular endocardial fractional shor teningcircumferential stress relationship versus midwall shortening-st ress relationship in the subjects divided according to relative wall t hickness (RWT) and left ventricular mass indexed by body surface area. Patients Borderline-to-mild hypertensives [n = 635, aged 33 +/- 0.3 y ears (mean+/-SEM), office blood pressure 146 +/- 0.4/94 +/- 0.2 mmHg ( means +/- SEM)] in the Harvest Study and 50 normotensive controls with similar age and sex distributions. Methods Blood pressure was measure d by 24 h ambulatory monitoring. Left ventricular dimensional and func tional indices were assessed by M-mode echocardiography. Results In th e subjects divided into quintiles of RWT, the left ventricular shorten ing-stress relationship was increased in a parallel fashion when calcu lated by endocardial and by midwall measurements for RWT less than or equal to 0.35. Instead, for greater RWT values (greater than or equal to 0.37) endocardial measurement constantly gave larger values than di d midwall measurement Both the endocardial and the midwall shortening- stress relationships progressively decreased with increasing RWT. Howe ver, the endocardial shortening-stress relationship remained greater t han normal at any RWT, whereas the midwall shortening-stress relations hip was decreased for RWT greater than or equal to 0.37. In a multiple -regression analysis RWT was the most potent predictor of the endocard ialmidwall shortening difference, left ventricular mass and 24 h systo lic blood pressure being the second and third most potent predictors. Conclusions We found a parallel increase in indices of cavity emptying and of myocardial contractility in mild hypertensive subjects with no rmal left ventricular geometry. When the RWT is increased, ejection ph ase indices may be normal in the presence of decreased myocardial cont ractility.