Narayanan, Meena

BackgroundDiastolic dysfunction (DD) is associated with exercise intolerance. To evaluate mechanisms of exercise intolerance in patients with DD, we performed bicycle stress echocardiography.Method and ResultsDoppler measurements were performed at baseline, during exercise and recovery in 26 patients (58 ± 11 years) with DD and normal left ventricular ejection fraction and 6 normal controls (53 ± 5 years). Compared to controls, patients achieved similar target heart rates but lower METs (5.5 ± 2 vs. 9.8 ± 3, P < 0.01) and a higher peak pulmonary artery pressure (PAP) at peak exercise (50 ± 13 vs. 32 ± 7 mmHg, P < 0.01) despite similar PAP at rest and similar mean blood pressure at peak exercise (110.4 ± 18.0 vs. 106.9 ± 11.4 mmHg, P = NS). In patients versus controls, mitral E/E' was similar at baseline (10 ± 3 vs. 8 ± 1.3, P = NS) but higher at recovery (11 ± 2 vs. 7 ± 2, P < 0.05), % mitral filling time was shorter at baseline, onset, and peak exercise, whereas % LV and RV ejection time was similar to controls throughout exercise. Compared to controls, lateral mitral annular S' (11.8 ± 2.5 cm/sec vs. 14.9 ± 1.9 cm/sec, P < 0.02) and tricuspid annular S' (14.8 ± 4.1 cm/sec vs. 19.4 ± 4.0 cm/sec, P < 0.05) were lower at peak exercise in patients.ConclusionDiastolic filling time is reduced at rest and stress while LV ejection time increases normally during exercise in DD. There is a reduced systolic reserve in LV and RV during exercise in DD. These mechanisms contribute to exercise intolerance and elevation of left atrial and PAP in patients with DD.