Differences in the duration of total ejection between right and left ventricles in chronic pulmonary hypertension

Chronic pulmonary hypertension (cPH) is known to delay pulmonic valve closure resulting in a closely split second heart sound. We decided to measure total duration of right (RV) and left ventricular (LV) outflow tract (RVOT and LVOT) spectral signals using pulsed Doppler to determine if this approach was useful in identifying this narrowing in auscultation that should then result in a shorter temporal difference between the ejection of both ventricles.

Standard measures of RV and LV performance as well as Doppler data was collected from 85 patients divided into two groups according to their estimated pulmonary artery systolic pressure obtained at the time of their echocardiographic examination. Difference in ejection between the ventricles was defined as the difference in ejection time between RVOT and LVOT, measured in milliseconds.

Chronic PH patients had a shorter total duration between RVOT and LVOT ejection time (-15 ± 16 ms vs. 22 ± 14 ms; P < 0.0001) than individuals without PH. This difference in total duration between RVOT and LVOT ejection not only showed a significant negative correlation with both PASP (r = -0.65; P < 0.0001) but also with pulmonary vascular resistance (PVR; r = -0.60; P < 0.0001).

Shorter duration between RVOT and LVOT ejection is likely to explain the closely split second heart sound in cPH patients. When accurate echocardiographic assessment of RV function in cPH patients remains problematic due to the unusual geometry of this cardiac chamber; Doppler measures can simplify patient identification and follow up.