Radiofrequency ablation of a left accessory pathway unmasks classic Chagas' disease ECG pattern.

In patients with chronic Chagas' cardiomyopathy, there are forms of the disease that affect the electrical conduction system almost exclusively. The most common disorders include right bundle branch block alone or in association with left anterior fascicular block. We present an unusual case of a patient with Chagas' cardiomyopathy in association with a preexcitation syndrome.