Time Interval Between Right Ventricular Early Diastolic Velocity by Tissue and Pulse Wave Doppler: An Index of Right Atrial Pressure in Pulmonary Hypertension Patients

Background: A reversal of time difference between the onset of early diastolic velocity (e') during tissue Doppler imaging and the onset of mitral inflow (E) has been observed in cases of elevated left atrial pressure. Whether this interval (T_e'-E) may be useful to assess right atrial pressure has never been investigated, neither in healthy subjects nor in pulmonary hypertension patients. Methods: Right ventricular T_e'-E was assessed in patients with pre-capillary pulmonary hypertension and compared with healthy volunteers who underwent comprehensive echocardiography examination. T_e'-E is the difference between the interval from R wave at the superimposed electrocardiogram to the e' wave during right ventricular tissue Doppler imaging and the interval from the R wave to transtricuspid E wave during pulsed wave Doppler imaging. Right atrial pressure was invasively measured in pulmonary hypertension patients. Results: Fifty-six patients were enrolled. T_e'-E was prolonged in pulmonary hypertension subjects compared with healthy subjects (p < 0.001). Amongst the pulmonary hypertension patients, strong correlations were found between T_e'-E and right atrial pressure (r = -0.885, p < 0.001), systolic pulmonary pressure (r = -0.85, p < 0.001) and the duration of tricuspid regurgitation (r = 0.72, p < 0.001). The area under the receiver operating characteristic curve of T_e'-E in identifying right atrial pressure higher than 15 mm of mercury was 0.992 (sensitivity 100%, specificity 83%). Conclusions: In contrast to the left ventricle, there is a delay in the proto-diastolic filling in pulmonary hypertension patients, which correlates with the increase in systolic pulmonary arterial pressure, right atrial pressure, tricuspid regurgitation duration and restrictive diastolic pattern.