Regional contribution to ventricular stroke volume is affected on the left side, but not on the right in patients with pulmonary hypertension

Abstract

To develop more sensitive measures of impaired cardiac function in patients with pulmonary hypertension (PH), since detection of impaired right ventricular (RV) function is important in these patients. With the hypothesis that a change in septal function in patients with PH is associated with altered longitudinal and lateral function of both ventricles, as a compensatory mechanism, we quantified the contributions of these parameters to stroke volume (SV) in both ventricles using cardiac magnetic resonance (CMR). Seventeen patients (10 females) evaluated for PH underwent right heart catheterization (RHC) and CMR. CMR from 33 healthy adults (13 females) were used as controls. Left ventricular (LV) atrioventricular plane displacement (AVPD) and corresponding longitudinal contribution to LVSV was lower in patients (10.8 ± 3.2 mm and 51 ± 12 %) compared to controls (16.6 ± 1.9 mm and 59 ± 9 %, p < 0.0001 and p < 0.01, respectively). This decrease did not differ in patient with ejection fraction (EF) >50 % and <50 % (p = 0.5) and was compensated for by increased LV lateral contribution to LVSV in patients (49 ± 13 % vs. 37 ± 7 %, p = 0.001). Septal motion contributed less to LVSV in patients (5 ± 8 %) compared to controls (8 ± 4 %, p = 0.05). RV AVPD was lower in patients (12.0 ± 3.6 mm vs. 21.8 ± 2.2 mm, p < 0.0001) but longitudinal and lateral contribution to RVSV did not differ between patients (78 ± 17 % and 29 ± 16 %) and controls (79 ± 9 % and 31 ± 6 % p = 0.7 for both) explained by increased RV cross sectional area in patients. LV function is affected in patients with PH despite preserved global LV function. The decreased longitudinal contribution and increased lateral contribution to LVSV was not seen in the RV, contrary to previous findings in patients with volume loaded RVs.

Keywords: Cardiac magnetic resonance imaging; Longitudinal function; Pulmonary hypertension; RV pressure load; Right heart catheterization; Septal and lateral function; Stroke volume.