Exercise echocardiography of left ventricular diastolic function in healthy subjects Insights from the RIGHT-NET

Background Exercise transthoracic Doppler echocardiography (TTE) is considered suggestive of left ventricular (LV) diastolic dysfunction when the ratio of mitral Doppler E to tissue Doppler e′ waves is >15 with or without a peak tricuspid regurgitation velocity (TRV) >3.4 m/s. However, these measurements may be affected by exercise intensity. The aim of the study was to define the normal limits of LV diastolic function indices during exercise TTE. Methods One hundred ninety-two healthy adults (47% females, aged 16-76 years) underwent resting and exercise TTE on a semirecumbent cycle ergometer. LV diastolic measurements were acquired at baseline and midlevel exercise (heart rate ≤110 bpm) fusion of E and A waves. TRV was acquired at rest and at peak exercise. The E/e′ ratio was calculated with e′ as the average of septal and lateral measurements. Results At midlevel exercise, E/e′ increased modestly from 6.3 ± 1.9 to 7.3 ± 2.3 (P < 0.001) as a function of workload and cardiac output (CO), independently of sex and age. The 95th percentile of exercise E/e′ was 11.8. The slope of E/e′/CO was 0.4 ± 1.2/L/min. The slope of TRV/CO was 10.8 ± 11.5 cm/s/L/min. The upper 95% confidence interval of the E/e′/CO and TRV/CO slopes were 0.6/L/min and 13.1 cm/s/L/min, corresponding to an E/e′ of 13.2 and a TRV of 3.4 m/s at a CO of 15 L/min. Conclusions In healthy adult subjects, E/e′ slightly increased during midlevel exercise. Both E/e′ and TRV are exercise intensity-dependent and would therefore be better expressed as a function of CO for the diagnosis of normal vs abnormal LV diastolic response to exercise.