Relationship between Myocardial Right Ventricular Relaxation Time and Pulmonary Artery Pressure in Patients with Pulmonary Arterial Hypertension

Recent developments in echocardiography made assessing pulmonary arterial hypertension (PAH) in the heart, a suitable choice. This study aimed to investigate the association of myocardial right ventricular relaxation time and systolic pulmonary artery pressure (SPAP) in PAH patients. The present study evaluated 74 patients with PAH (n=49) and age- and sex-matched healthy controls (n=25). All patients underwent transthoracic echocardiography. We evaluated the right ventricular (RV) function's echocardiographic parameters, including IVRT, IVCT, S, E, A, S’, E’, A’, ET, DT, TAPSE, FAC, and SPAP. We found no significant differences in age and gender between the two studied groups (p>0.05). However, we observed a significant difference in IVRT, IVCT, E’, A’ (p=0.004), A, S’, DT, TAPSE, FAC and SPSP (p<0.001 for all cases) between two studied groups. Unlike the control group, we revealed a significant correlation between S’ and E’ (r=0.45, p=<0.001), S’ and A’ (r=0.66, p=<0.001), S’ and FAC (r=0.3, p=0.035), A and A’(r=0.4, p=0.004), TAPSE and FAC (r=0.82, p=<0.001), TAPSE and SPAP (r= -0.43, p=0.002), MPI and A (r= -0.35, p=0.013), MPI and ET (r= -0.72, p=<0.001), E/A and E/E’(r=0.47, p=<0.001), and BSA and S’ (r= -0.3, p=0.011). In addition, no meaningful association was found between SPAP and IVRT and IVCT (p>0.05). Our findings revealed that IVRT and IVCT might not be affected by the SPAP and, therefore, could be used in the assessment of right ventricular function in patients with PAH.