Inappropriate sinus tachycardia in a heart transplant successfully treated with ivabradine

A 55-year-old male with history of two prior orthotopic heart transplants presented with his third heart failure hospitalization in 4 months with a steady decrement in left ventricular ejection fraction (LVEF) from 65% to 35%. During each hospitalization, he demonstrated a long-RP tachycardia in the 130 beats/min (Panel A). His tachycardia preceded the deterioration in LVEF. An extensive evaluation included a right heart catheterization showing elevated filling pressures, coronary angiography showing no epicardial coronary artery disease, and endomyocardial biopsies at two different times finding no evidence of allograft rejection. Owing to persistent tachycardia, he underwent electrophysiology study that showed earliest atrial activation in the sinoatrial nodal region (Panel B). Outpatient Holter monitoring revealed a mean heart rate (HR) averaging 127 beats/min (range 116 –147 bpm). Given concern for inappropriate sinus tachycardia (IST) and the worsening LVEF, tachycardia induced cardiomyopathy (TCM) was presumptively diagnosed. Pharmacologic therapy for atrioventricular nodal blockade was hindered by hypotension. Initiation of ivabradine decreased resting HR to 9 0–110 beats/min. The slower HR persisted with ongoing therapy. Follow-up echocardiography showed LVEF recovery with no further heart failure hospitalizations. This is the first report of reversal of IST-related TCM in a cardiac transplant patient with ivabradine.
Source: Europace - Category: Cardiology Source Type: research