[Determinants of exercise capacity in hypertensive patients]

An impaired exercise capacity is common in hypertensive patients (pts) and factors affecting exercise capacity are not completely elucidated. The aim of the study was to investigate factors influencing exercise capacity in hypertensive pts Studied group consisted of 41 pts (18 males, 23 females) mean age 54.2 +/- 11.9 with essential hypertension and without coronary artery disease. Each patient underwent an echocardiographic examination followed by treadmill exercise test. Echocardiographic assessment comprised estimation of left ventricular (LV) mass index (LVMI), pattern of LV geometry, ejection fraction (LVEF), fractional shortening (LVFS), peak and integral velocities of early (E, Ei) and late (A, Ai) transmitral flow, deceleration time of E wave (DT), isovolumic relaxation time (IVRT), duration of A wave (A-dur), total ejection isovolume index (TEI), E (ETT) and A (ATT) wave transit time to the LV outflow tract, flow propagation velocity of E wave (EP), peak and integral velocities of systolic (S, Si), diastolic (D, Di) and atrial reversal (AR, ARi) pulmonary venous flow, duration of AR wave (AR-dur), acceleration (SAT) and deceleration (SDT) of systolic pulmonary venous flow, systolic forward fraction of pulmonary venous flow (SFF). Exercise capacity was assessed by exercise time and total workload expressed in MET. Significant correlations were found for MET and: age (r = -0.49, p < 0.001), A (r = -0.62, p < 0.001), E/A ratio (r = 0.55, p < 0.004), Di (r = 0.55), p < 0.004), ARi (r = -0.38, p < 0.01), SFF (r = 0.46, p < 0.002). Exercise time correlated with A (r = -0.61, p < 0.001), E/A ratio (r = 0.41, p < 0.04), Di (r = 0.51, p < 0.009), ARi (r = -0.35, p < 0.02), SFF (r = -0.51, p < 0.008), S/D ratio (r = -0.47, p < 0.01). Other investigated parameters did not correlate with both MET and exercise time. By stepwise multiple linear regression analysis Di and ARi were the only determinants of MET (multiple r = 0.85, p < 0.0001) whereas A and Di turn out to be the only independent predictors of exercise time (multiple r = 0.76, p < 0.0004). In hypertensive pts: 1. diastolic function of LV is a principle determinant of exercise capacity, 2. integral velocity of diastolic and atrial reversal pulmonary venous flow and peak velocity of late transmitral flow are the best predictors of exercise tolerance.