Background: Vascular stiffening of the large arteries is a common feature in hypertensive patients. Uncoupling between heart and vessel may affect left ventricular (LV) function especially during exercise. We hypothesized the augmentation of LV longitudinal contraction and relaxation during exercise would be blunted in hypertensive patients with uncoupled vascular ventricular interaction (VVI). Therefore, the purpose of study was to evaluate LV longitudinal function at rest as well as during exercise in hypertensive patients and to compare its function according to VVI change during exercise.
Methods: Doppler echocardiographic parameters and blood pressure were measured at rest and during supine bicycle exercise (25W, 3 minutes increments) in 141 hypertensive patients older than 40 years (50 male, mean age 59±9 years). Arterial elastance (Ea), end-systolic ventricular elastance (Ees) and VVI index (Ea/Ees) were calculated at rest and peak exercise. The patients were divided into two groups; Group I (n=104), normal VVI response during exercise; Group II (n=37), abnormal VVI response during exercise, defined as increased VVI index at peak exercise compared with at rest.
Results: None had echocardiographic evidence of resting or inducible myocardial ischemia. There were no significant differences in conventional echo parameters and mitral inflow velocities at rest between the two groups. Mitral annular systolic (S') and diastolic (E') velocities at rest were also similar between the groups. However, S' (8.8±2.0 vs. 7.9±1.8 cm/s, p=0.023) and E' (9.0±2.0 vs. 7.5±2.2 cm/s, p=0.003) at peak exercise were significantly smaller in Group II. The magnitude of increment of E' (3.5±1.7 vs. 2.3 ±1.8 cm/s, p=0.012) and S' (2.2±1.9 vs. 1.5 ±1.6 cm/s, p=0.04) with exercise were also significantly smaller in Group II. The Ea (2.4±0.6 vs. 2.9±0.6 mmHg/ml, p<0.001) at peak exercise was significantly higher and Ees (5.3 ±2.1 vs. 4.5±1.4 mmHg/ml, p=0.034) at peak exercise was significantly smaller in Group II.
Conclusions: Vascular stiffening and abnormal VVI during exercise was associated with abnormal LV longitudinal systolic and diastolic functional reserve during exercise in hypertensive patients
|