Normal parameters of right ventricular mechanics with exertion in healthy individuals: a tissue Doppler imaging study

Tissue Doppler imaging (TDI) has been a useful tool to evaluate of resting right ventricular (RV) function; however, the response of the RV to exercise has not been well established. This study attempts to determine RV mechanics at rest and immediately after exercise in healthy subjects using TDI and to define normal values.

The authors studied 30 patients (mean age: 46 ± 14 years) who underwent a treadmill stress echocardiogram and had a normal exercise response without cardiac abnormalities. RV end-diastolic and end-systolic areas and RV fractional area change were measured. In addition, longitudinal RV strain and velocity generation were measured.

Immediately postexertion, a significant decrease in RV end-systolic area (6.4 ± 2.5 cm² versus 4.6 ± 1.5 cm², P < 0.001), increase in RV end-diastolic area (14.1 ± 4.5 cm² versus 15.3 ± 3.8 cm², P = 0.05) and a higher RV fractional area change (54 ± 6.9% versus 69 ± 7.7%, P < 0.001) were observed. RV strain increased significantly with exercise at both the base (-18.4 ± 7.7% versus -26.2 ± 10.9%, P = 0.005) and mid-RV lateral wall (-29.9 ± 8.7% versus -40.2 ± 11%, P < 0.001). RV velocity also increased significantly at both the base (8.3 ± 2.1 cm/sec versus 12.7 ± 2.5 cm/sec, P < 0.001) and mid-RV lateral wall (4.4 ± 1.6 cm/sec versus 8.1 ± 4.1 cm/sec, P = 0.001).

Immediately postexercise, TDI seems to be a useful tool for assessing RV mechanics and function. Whether RV velocity and strain may be used to detect subclinical RV dysfunction during exercise will require further study.