Effects of respiration on the velocity of tricuspid regurgitation and estimation of systolic pulmonary artery pressure in patients with right ventricle systolic dysfunction

Objective. We investigated the effects of quiet respiration on the peak velocity of tricuspid regurgitation (TR) and estimation of systolic pulmonary artery pressure (SPAP) in patients with right ventricle (RV) systolic dysfunction using Doppler echocardiography. Methods. Continuous-wave Doppler spectra of TR were recorded in 32 patients with and 28 controls without RV systolic dysfunction. Electrocardiography and respiratory tracing were recorded simultaneously. Expiratory and inspiratory peak velocities of TR were acquired and averaged for five consecutive respiratory cycles. The SPAP during expiration and inspiration was calculated. Results. The velocity of TR and SPAP was not significantly different between expiration and inspiration in controls (2.77 ± 0.23 and 2.82 ± 0.26 m/s, P = 0.776; 35.94 ± 4.96 and 36.18 ± 5.12 mmHg, P = 0.747), whereas the velocity of TR and SPAP decreased significantly from expiration to inspiration in patients with RV systolic dysfunction (3.27 ± 0.35 and 2.59 ± 0.22 m/s, P < 0.001; 53.72 ± 7.39, 38.45 ± 5.63 mmHg, P < 0.001). Conclusions. Quiet respiration has significant effects on the velocity of TR in patients with RV systolic dysfunction. This factor should be taken into account when using Doppler echocardiography to estimate these patients’ SPAP, and the measurements should be performed in patients at the end of expiration.