An Elderly Case of Idiopathic Dilatation of the Right Atrium in Which Right-sided Heart Failure was Exacerbated by Drug-induced Bradyarrhythmia.

We describe an elderly case of idiopathic dilatation of the right atrium in which right-sided heart failure was exacerbated by drug-induced bradyarrhythmia. An 84-year-old man, who had a 10-year history of episodic edema, was treated with proscillaridin and verapamil hydrochloride at another hospital. He had experienced a poor appetite and general malaise 2 months previously, and exertional dyspnea 10 days previously. On admission, he had jugular venous dilatation, systemic edema, and hepatomegaly. On auscultation, a third heart sound originating from the right ventricle and systolic murmur of tricuspid regurgitation were heard. An admission electrocardiogram showed an atrial standstill and junctional escape rhythm with a QRS rate of 31 beats/minute. Chest roentgenogram revealed a bilateral pleural effusion and cardiomegaly with a cardiothoracic ratio of 76%, but no pulmonary congestion. Echocardiogram disclosed idiopathic dilatation of the right atrium and secondary tricuspid regurgitation. He was given a diagnosis of right-sided heart failure due to idiopathic dilatation of the right atrium exacerbated by bradyarrhythmia, which was suspected to derive from the side effects of proscillaridin and verapamil hydrochloride. Thus, these agents were withheld. In addition, the patient reduced sodium intake and was treated with diuretics and beta-adrenergic agonist. Thereafter, right-sided heart failure markedly improved. At the time of the last follow-up 16 months after discharge, he felt well.