Because the Task Force Criteria (TFC) are often not sufficient, the diagnosis of arrhythmogenic cardiomyopathy (AC) remains a challenge. The finding of low voltage areas (LVA) in the triangle of dysplasia, during a mapping in the electrophysiology lab, supports AC diagnosis but at the cost of an invasive procedure. A new noninvasive ECG high-resolution mapping tool, using a 252 leads vest and a CT scan 3D reconstruction (CardioInsight Technologies, Inc., Cleveland, Ohio), has the potential to unmask early AC disease.

To identify LVA in the triangle of dysplasia by an ECG noninvasive epicardial mapping system in patients with suspected AC and negative TFC.

Five patients (pts) were included (3 males, 47.4±12.6 years). Median follow-up was 26 months [18; 97]. Pts were divided according to TFC between AC possible/borderline with high clinical suspicion (2 pts, respectively 1 minor TFC & 1 major plus 1 minor TFC) and definite AC (3 pts). For each pt a noninvasive high-resolution epicardial mapping of both ventricles was performed. LVA were defined as <30% of maximum ventricular voltage. The triangle of dysplasia including basal right ventricle (RV), RV outflow tract, and posterolateral left ventricle (LV) was specifically analyzed.

The noninvasive epicardial voltage maps revealed LVA in the 3 sides of the triangle of dysplasia in both pts with high clinical suspicion of AC but non-conclusive TFC (Fig. 1). Interestingly, these two pts had no major criteria by MRI (RV end-diastolic volume respectively 94 and 57ml/m², RV ejection fraction 51 and 69%, and homogeneous segmental contraction), suggesting an early stage of the disease. All pts with defined AC had LVA in ≥2 sides of the triangle of dysplasia.

An ECG noninvasive epicardial mapping can improve the diagnosis of early stage AC by demonstrating the presence of previously unknown lesions in the triangle of dysplasia.