Right ventricular voltage mapping predicts clinical performance in patients with pulmonary arterial hypertension

Abstract Background Right ventricular (RV) failure is the most important determinant of survival among patients with pulmonary arterial hypertension (PAH). However, current risk prediction models for RV failure have limited performance1. Objective This trial assessed the RV utility of voltage mapping in patients with PAH and examined correlation of findings with traditional clinical markers of RV performance. Methods In this prospective single center study, consecutive PAH patients underwent RV electro-anatomical mapping (EAM) at the time of right heart catheterization (RHC) for PAH vasodilatory therapy titration from January 2023 to November 2024. For EAM, a voltage map was created in sinus rhythm using a multi-spline catheter. Peak-to- peak unipolar voltage 5.0 mV was defined as epicardial scar. Patient demographics, transthoracic echocardiographic (TTE) findings and RHC parameters were correlated with presence of RV epicardial scar. Results 19 patients with PAH underwent EAM at the time of RHC. Mean age 57±13 years, 17 (89%) females, BMI 31±9 kg/m2, and LVEF 53±24%. After EAM, 13 (68%) patients had RV epicardial scar, and it involved 9.1±10.6% of the RV epicardial surface area. Interestingly, patients with scar had a shorter time to diagnosis of PAH (scar: 1.3 (IQR 2.1) vs no scar: 6.9 (IQR 8.3) years, p=0.028), decreased six-minute walk distance (scar: 363±97 vs no scar: 501±70 meters, p=0.031), and higher pulmonary capillary wedge pressure (scar: 9.8±2.2 vs no scar: 13.9±6.0, p=0.047). Otherwise, the presence of scar was not associated with other differences in baseline TTE characteristics, RHC parameters, or RV metrics (Table 1). Conclusion A subset of patients with PAH undergoing vasodilator therapy titration demonstrate RV epicardial scar on EAM, and the presence of scar associates with traditional clinical markers of RV performance. The long-term clinical implications of RV epicardial scar require further investigation.