Feasibility of Combined Unipolar and Bipolar Voltage Maps to Improve Sensitivity of Endomyocardial Biopsy

Background - Endomyocardial biopsy (EMB) has a low sensitivity. Electroanatomic voltage mapping (EVM) is effective in guiding EMB thanks to its ability in identifying and locating low-voltage regions. The analysis of unipolar EVM can correlate with epicardial pathological involvement. We evaluated the unipolar EVM in EMB areas to determine whether it can increase EMB sensitivity in diagnosing epicardial diseases. Methods and Results - We performed endocardial bipolar EVM-guided EMBs in 29 patients and we analyzed unipolar EVM at withdrawal sites. Eighty myocardial samples were collected (mean, 2.8±0.9; median, 3 fragments per patient) and 60 were suitable for histological analysis. Ten specimens (17%) were collected from an area with discordant normal bipolar/low-voltage unipolar EVM and they were diagnostic or suggestive for arrhythmogenic right ventricular dysplasia/cardiomyopathy in 6 patients, for myocarditis and sarcoidosis in 1 patient each. Six samples (10%) were collected from an area with discordant low-voltage bipolar/normal unipolar EVM and they showed nonspecific features. The sensitivity of unipolar EVMs for a diagnostic biopsy finding EMB was significantly higher compared with bipolar EVMs analyzed according to samples (P