Do healthy individuals develop intraventricular gradients during exertion?

The development of intraventricular gradients on exertion has been described in various clinical settings. Recently, a small study using exercise echocardiography in healthy subjects, with image acquisition immediately after exercise termination, failed to demonstrate the development of intraventricular gradients. In the present study, we performed exercise echocardiography in 34 healthy individuals, mean age 50 +/- 12 years (age range, 28 to 70), 17 of whom were male. The development of obstructive intraventricular gradients and systolic anterior motion (SAM) of the mitral valve during exertion was evaluated using Doppler echocardiography during exercise treadmill testing according to the Bruce protocol. Exercise testing had a mean duration of 653 +/- 144 sec and a mean of 92 +/- 8% of age-predicted maximum heart rate was attained. The mean double product achieved at peak exercise was 25,703 +/- 2887. Maximum left ventricular outflow tract velocity measured using continuous-wave Doppler and in left lateral decubitus was significantly different from that obtained in the orthostatic position (125 +/- 16.3 vs. 111 +/- 13.9 cm/sec, p<0.000). Maximum left ventricular outflow tract velocity at three minutes of exercise was also significantly different from that obtained in the resting orthostatic position (163 +/- 29 vs. 111 +/- 13.9 cm/sec, p<0.000). Maximum left ventricular outflow tract velocity at peak exercise was also higher than that obtained at three minutes of exercise (199.9 +/- 23 vs. 163 +/- 29 cm/sec, p<0.000). The maximum velocity measured at peak exercise in the study population was 237 cm/sec. None of the patients in this study demonstrated a pattern of intraventricular flow with endsystolic peak velocity consistent with the development of an intraventricular gradient. Similarly, none of the patients developed SAM of the mitral valve during exercise. We concluded that, in the present study, a group of healthy subjects did not develop left intraventricular gradients or SAM during exertion.