A “Towering” ECG: Massive Ventricular Depolarization Waves in a Newborn with Multiple Cardiac Rhabdomyomas

Excerpt

During routine neonatal examination on day one of life, a heaving precordium with a prominent apex beat was noted in a term female infant. A grade 4/6 pansystolic murmur was heard throughout the precordium, loudest at the apex and radiating to the back. Chest x–ray showed cardiomegaly with normal lung fields. Electrocardiogram (ECG) showed sinus rhythm with strikingly tall R waves in all chest leads. This was most impressive in leads V3 and V4, with the R waves not just crossing but shooting off the ECG report (90 mm amplitude) (Fig. 1A). The voltage settings were halved, but the tracings still overlapped (Fig. 1B). Echocardiogram showed multiple echodensities, particularly in the left ventricular free wall, adjacent to the aortic valve (causing almost complete obstruction of left ventricular outflow), the mitral valve (causing regurgitation and stenosis), and the interventricular septum (causing right ventricular outflow tract obstruction) (Fig. 2). This was suggestive of multiple rhabdomyomas (later confirmed on histology). The infant required mechanical ventilation and Prostaglandin E2 infusion to maintain patency of the ductus arteriosus. Resection of the masses causing obstruction to the left ventricular and left atrial outflow tracts was performed on day 3. Furthermore, investigations showed multiple subependymal nodules, a possible astrocytoma in the brain, and multiple cysts in the kidney, which supported the diagnosis of tuberous sclerosis. She presented again in a state of cardiovascular collapse at 5 weeks of age with supraventricular tachycardia requiring electrical cardioversion, ventilation, and inotropic support.

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