Ratio of right to left ventricular ejection: a pilot study using Doppler to detect interventricular dyssynchrony

Chronic pulmonary hypertension (cPH) is known to delay maximal right ventricular (RV) deformation, causing mechanical dyssynchrony, which previously has been identified only through the use of myocardial tissue Doppler imaging. However, alterations between RV and left ventricular (LV) ejection should be easily identified during routine echocardiographic examinations.

We hypothesized that assessment of differences in ejection fraction between left and right ventricles would be detected using pulsed Doppler.

Standard echo and Doppler data were collected from 30 patients without PH (mean age, 53 ± 7 y; mean pulmonary artery systolic pressure [PASP], 31 ± 5 mm Hg) and from 40 patients with cPH (mean age, 53 ± 13 y, P not significant; mean PASP, 82 ± 24 mm Hg, P<0.00001). Temporal differences in the ejection of both ventricles were measured as the ratio of total duration of RV to LV outflow tract (RVOT and LVOT) pulsed Doppler signals.

A ratio (<0.99) of RVOT to LVOT total duration of ejection was found not only to be the best Doppler parameter to identify an abnormal pulmonary artery systolic pressure, with a 90% sensitivity and 100% specificity (area under the curve 0.958, P = 0.0001), but also identified differences in the temporal ejection between the 2 ventricles, or dyssynchrony, as a result of cPH.

The ratio of pulsed Doppler RV to LV total duration of ejection is easily obtainable and appears useful in identifying the presence of interventricular dyssynchrony in cPH patients. A prospective study is now required to determine if this Doppler ratio can identify minute changes in the ejection of both ventricles as a result of changes in disease status or response to PH therapy.