Electroanatomic mapping of the right ventricle in a patient with a giant epsilon wave, ventricular tachycardia, and cardiac sarcoidosis.

A 47-year-old man presented with sustained monomorphic ventricular tachycardia of right ventricular origin. Surface ECG recorded during sinus rhythm showed a bizarre "double QRS" pattern. Biventricular cardiomyopathy was found with predominant right ventricular involvement, due to cardiac sarcoidosis. Electroanatomic mapping was used to characterize the right ventricular substrate abnormalities and to decipher the specific activation abnormalities responsible for the ECG findings.