Three-dimensional echocardiography to evaluate right atrial volume and phasic function in pulmonary hypertension

Objective: Pulmonary hypertension (PH) impairs right ventricular (RV) systolic and diastolic function, which in turn induces compensatory changes in right atrial (RA) function; the diverse effects on RA function are subject to much debate. We hypothesized that RA function plays a more important role in compensating RV dysfunction, than mere prevention of clinical failure in patients with PH.

Methods: We studied 54 patients with PH and 23 healthy controls. RA volume, including maximum RA volume, minimum RA volume, and the volume before atrial systole, was evaluated by 3DE. RA maximum volume index (V_max I), total emptying volume index (TotEVI), passive emptying volume index (PassEVI), and active ejection fraction (ActEF) were calculated. Receiver operating characteristic curve analysis was used to determine the sensitivity and specificity of various cutoff levels of the variables measured for predicting World Health Organization functional class (WHO-FC) IV in patients with PH.

Results: RAV_max I in patients with PH was higher than that in controls. In patients with PH, the TotEVI was significantly higher, while PassEVI was significantly lower as compared to that in controls. ActEF was increased in patients with WHO functional class (WHO-FC) III PH as compared to that in controls (P = .003) but was reduced in more advanced cases (WHO-FC IV). In addition, the area under the curve of 3D RA ActEF was larger than those of 2D RA ActEF, RA GLS, RA area, FAC, TAPSE, and RIMP (P < .01 for all) for predicting WHO-FC IV.

Conclusion: We demonstrated that RA function plays a more important role in compensating RV dysfunction then mere prevention of clinical failure in PH.