Chronic Pulmonary Hypertension Causes Significant Interventricular Spatiotemporal Dyssynchrony When Onset of Diastolic Flow Signals Are Assessed by Color M-Mode

Background: Color M-mode (CMM) has been useful in characterizing left ventricular (LV) relaxation as well as providing information regarding right ventricular (RV) filling dynamics and pressure gradients. The spatiotemporal resolution of CMM offers a unique opportunity to study the effect of chronic pulmonary hypertension (cPH) on biventricular diastolic function. Methods: Propagation velocities of LV and RV diastolic flows were obtained from 20 individuals with normal pulmonary artery systolic pressures, designated Group I (mean age 50 ± 12 years and 32 ± 6 mmHg) and from 30 patients with cPH, designated Group II (mean age 55 ± 14 years and 81 ± 25 mmHg). Results: Group II patients not only had a significant difference between RV and LV onset of early (13 ± 55 vs. −223 ± 333 msec; P < 0.003) and late (−494 ± 467 vs. −125 ± 258 msec; P < 0.001) diastolic flows; but also had lower propagation velocities of the main RV (40 ± 10 vs. 28 ± 10 cm/sec; P < 0.0001) and LV (52 ± 11 vs. 37 ± 15 cm/sec; P < 0.0003) diastolic flows than Group I individuals. Conclusions: It appears that cPH disrupts not only RV and LV diastolic signal distribution but also their temporal occurrence as well as reducing the propagation velocities of the main diastolic signals in both ventricles. These results seem to imply that cPH causes significant interventricular diastolic dyssynchrony and further studies are now needed to correlate these findings with regard to symptoms and patient clinical outcomes. (Echocardiography 2012;29:653–660)