Résumé
The objective of the study was to determine the effects of isometric exercise on the diastolic function in patients with aortic stenosis without coronary lesion (group 1, G1, n = 9) and with coronary lesion (group 2, G2, n = 11). Patients subjected to a cardiac catheterization performed isometric exercise until their heart rate increased in 32 +/- 9% compared to baseline. The left ventricular systolic pressure, the +dP/dtmax, and the end diastolic pressure (LVEDP) were measured, and the time constant of pressure decay (tau, tau) was calculated. The +dP/dtmax increased in G1 and G2 during exercise, from a value of 1989 +/- 190 and 2428 +/- 220 mmHg/sec up to 2286 +/- 214 y 2661 +/- 230 mmHg/sec, respectively, returning afterwards to its baseline value. The LVEDP increased during exercise in G1 and G2 from a value of 30.1 +/- 2.7 and 26.5 +/- 2.2 mmHg up to 38.4 +/- 1.7 and 36.1 +/- 4.0 mmHg, respectively (p < 0.05), returning to its baseline value only in G1. The tau (tau) increased during exercise in G1 and G2 from a value of 42.8 +/- 6.8 and 44.8 +/- 4.2 m/sec up to 55.3 +/- 9.2 and 60.4 +/- 5.9 msec respectively (p < 0.05), and remained elevated after exercise in both groups although it was statistically significant only in G2. The isometric exercise decreases the relaxation rate and increases the LVEDP in patients with aortic stenosis and left ventricular hypertrophy. After exercise, relaxation remained altered in the group of patients with coronary lesion. Alteration in the lusitropism and the increase of LVEDP after exercise suggest the presence of myocardial stunning