Stumbling Onto Cancer: Cardiomyopathy as the Initial Presentation of Malignancy
A 30-year-old healthy female patient with history of unexplained sinus tachycardia presented to the emergency department with chest pain, palpitations, and headache. The patient did not have any signs of heart failure on exam. The initial electrocardiogram (Figure 1) showed ventricular bigeminy, and cardiac enzymes were normal. Serial cardiac enzymes revealed a troponin elevation up to 2.78 ng/dl. Treatment with aspirin, clopidogrel, and intravenous heparin was initiated for suspected non-ST-segment elevation myocardial infarction. An echocardiogram showed hypokinesis of the basal segments of the left ventricle with preserved apical contractility and estimated left ventricular ejection fraction (LVEF) of 30% (Figure 2). Coronary angiography did not reveal obstructive coronary artery disease.
Due to concern for myocarditis, cardiac magnetic resonance imaging was performed, which confirmed the basal wall hypokinesis but showed no myocardial edema or delayed gadolinium enhancement (Figure 3). Incidentally, a 2.4 x 2.4 cm posterior mediastinal mass was noted adjacent to the upper thoracic spine (Figure 4). Single-photon emission computed tomography/computed tomography octreoscan showed uptake within the paraspinal mass (Figure 5).
What is the most likely mechanism of cardiomyopathy in this patient?