Background: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy characterized by fibrofatty replacement of the RV myocardium resulting in re-entrant ventricular tachycardia (VT). Cardiac magnetic resonance imaging (CMR) can detect strain-derived regional wall abnormalities.
Objective: In this study, we correlate regional strain abnormalities on cine CMR with electrophysiological substrate on invasive endocardial and epicardial mapping (EAM) in patients with ARVC.
Methods: Twenty-one patients with ARVC underwent high density endocardial and epicardial EAM of the RV in sinus rhythm as well as CMR study within 12 months of the procedure. Feature-tracking regional strain measurements were performed as previously described and correlated with the presence of EAM dense-scar (<0.5mV).
Results: CMR studies were successfully performed in all patients (30.2±9.9 years, 57% female). Compared to segments with normal bipolar voltage, mean CMR strain was significantly lower in segments with EAM dense scar both in the endocardial and epicardial surfaces (-13.1±8.5 vs -8.2±7.4, p=0.0002 and -13.2±7.3 vs -9.6±8.4, p=0.0015; respectively), as well as at successful VT ablation sites. On multivariate analysis, CMR strain was an independent predictor of endocardial EAM scar (OR=0.87, p=0.001) after controlling for age at ablation, gender, BMI, congestive heart failure, genotype, number of TFC, RV end-diastolic volume index, RV end-systolic volume index, RV and LV ejection fractions (AUC=0.85). CMR strain also independently predicted presence of epicardial scar (OR=0.91, p=0.002) on a similar multivariable analysis (AUC=0.75).
Conclusion: Regional myocardial wall strain on cine-CMR reliably predicted incident electrophysiological substrate on invasive EAM. This technique may allow improved diagnostic accuracy of CMR without the need for invasive procedures and may facilitate VT ablation procedural planning in ARVC.