Right ventricular dyssynchrony predicts outcome in pulmonary arterial hypertension when assessed in multiple CMR views.

Background: Right ventricular (RV) dyssynchrony or post systolic contraction (PSC) cause inefficient pumping and have not been investigated as prognostic markers in pulmonary arterial hypertension (PAH).

Objectives: To investigate if RV dyssynchrony and PSC are prognostic markers of transplantation-free survival in PAH and if multiple RV views improve the prognostication.

Methods: Patients with PAH undergoing cardiac magnetic resonance (CMR) between 2003-2021 were included. For strain analysis, endocardial end-diastolic RV contours were delineated in RV 3-chamber (RV3ch), 4-chamber (4ch) and midventricular short axis slice (SAX). RV dyssynchrony was defined as standard deviation of time to peak strain in the walls from one (4ch), two (4ch and SAX) or three views (4ch, SAX and RV3ch). PSC was defined as peak strain occurring after pulmonary valve closure. Outcome was defined as death or lung transplantation.

Results: One hundred-one patients (58±19 years, 66% women) were included. Median follow-up was 37 [51] months. There were 60 events (55 deaths and 5 lung transplantations). Outcome was associated with RV dyssynchrony from three views and with RV strain in 4ch. An increase of RV dyssynchrony - from 3 views - by 1% was associated with a 10% increased risk of lung transplantation or death. There was no association between outcome and RV dyssynchrony in one or two views nor with PSC.

Conclusion: Right ventricular dyssynchrony from three views were associated with outcome in PAH, whereas assessing dyssynchrony from one or two views and PSC were not. This implies that assessment of multiple instead of single RV views potentially could be used for prognostication in PAH.