Persistent atrial standstill and idioventricular rhythm in a patient with thalassemia intermedia.

We present a 57-year old male patient with thalassemia intermedia and right heart failure. He had a 30-year history of anemia and short-term iron therapy without blood transfusion. Hemoglobin level was 7.1 g/dl and hematocrit was 22.7%. White blood-cell and platelet counts, and serum ferritin level were normal. Electrocardiography showed irregular narrow QRS bradyarrhythmia, suggesting slow atrial fibrillation at a mean rate of 35 beats/min. Echocardiographic examination revealed dilatation of the right atrium and ventricle, depressed systolic right ventricular function, advanced tricuspid regurgitation, and mild pericardial effusion. In the electrophysiologic study, no electrical activity was recorded in the right atrium. It was inexcitable at multiple sites and no retrograde conduction to the right atrium could be elicited by ventricular pacing. His bundle (HB) recording showed fixed retrograde HB activation with ventricular rhythm originating from different foci. Retrograde V-H conduction time during ventricular rhythm was 95 msec and did not change. There was no retrograde nodal conduction. A VVIR pacemaker was implanted. During a six-month follow-up, he felt well, his functional capacity was NYHA class II, and his basic rhythm was widened QRS arrhythmia with a rate of 20 beats/min. To the best of our knowledge, atrial electrical inactivity together with right-heart failure and pericarditis confined to the right heart chambers has hitherto not been reported in thalassemic disorders.