|Home | About | Journals | Submit | Contact Us | Français|
A 62-year-old man presented with syncope and electrocardiographically recorded 3rd-degree atrioventricular block with slow junctional escape ventricular rhythm of 35 beats/min. He had a history of squamous-cell oropharyngeal carcinoma; this malignancy had been treated by means of radical resection 12 months before. When temporary pacing was performed, resistance was encountered crossing the tricuspid valve. Transthoracic echocardiography revealed a large echogenic infiltration that involved the interatrial septum, the atria, and the posterior left ventricular wall (Figs. 1A and and1B).1B). The right atrium was moderately dilated, with a highly mobile, heterogeneous mass within its cavity (Fig. 1C). Computed tomography of the thorax revealed a diffuse, hypodense mass, posterior to the myocardium, with marked thickening of the proximal interventricular septum and the medial wall of the right atrium (Fig. 1D). The patient decided upon conservative treatment, in view of his guarded prognosis. He was referred for palliative hospice care.
Although the most common cause of 3rd-degree atrioventricular block is degenerative in nature, the possibility of myocardial metastasis should be considered when complete atrioventricular dissociation is present in a patient who has a history of malignancies. Usually, myocardial metastases remain clinically dormant and are discovered only at autopsy.1 It is known from autopsy series that metastatic tumors of the heart can be found in 1.5% to 21% of patients who have malignancies. The most common cause of metastatic heart disease is bronchial carcinoma. In our patient's unusual circumstance, the 3rd-degree atrioventricular block was related to the disruption of the cardiac electrical conduction system by a giant metastatic tumor.
Address for reprints: Chao Yang Soon, MD, 960 Dunearn Rd., #01-26 Gardenvista, Singapore 589486, Singapore. E-mail: moc.liamg@ycnoos