Metastatic breast cancer history with pacing-induced cardiomyopathy and heart-function recovery

What happened, in summary

This 54-year-old woman had a history of breast cancer treated in 2007 with adriamycin, cyclophosphamide, paclitaxel, surgery, and thoracic radiotherapy. Years later, she was admitted with symptomatic trifascicular block. Because both subclavian veins were narrowed, likely from a prior port catheter on the right and radiotherapy on the left, doctors placed a single-chamber pacemaker through the right internal jugular vein with right ventricular pacing and right atrial sensing. Her baseline echocardiogram showed preserved left ventricular systolic function, several moderate valve regurgitations, and normal right-sided chambers. Three months after implantation, she progressed to complete atrioventricular block with 100% ventricular pacing. Six months after implantation, she developed worsening heart-failure symptoms and was admitted to cardiovascular intensive care. Examination showed congestion, a third heart sound, and a new loud tricuspid murmur. A left pleural effusion was drained and found to be transudative. Repeat echocardiography showed new moderate left ventricular systolic dysfunction with an ejection fraction of 38%, severe dyssynchrony, restrictive filling, new right ventricular dysfunction, severe tricuspid regurgitation, pulmonary hypertension, and pericardial effusion. Coronary angiography did not show obstructive disease, and catheterization ruled out constrictive physiology. The final diagnosis was pacing-induced cardiomyopathy. Cardiac resynchronization therapy could not be performed because of bilateral subclavian vein stenosis and osseous metastases involving the sternum and ribs. Instead, she received heart-failure medical therapy with ramipril, bisoprolol, spironolactone, empagliflozin, furosemide, and decongestive treatment. Symptoms improved markedly. At follow-up, she was NYHA class I despite continued 100% ventricular pacing, and echocardiography at 6 months showed complete recovery of biventricular function.