Mesothelioma of the atrioventricular node.

Abstract

SUMMARY A patient with Mobitz type 2 heart block caused by a mesothelioma of the atrioventricular node died of a subarachnoid haemorrhage at the age of 33 two years after implantation of a permanent pacemaker. Mesothelioma of the atrioventricular node is rare, and reported cases have all been diagnosed post mortem. Mesothelioma of the atrioventricular node should be considered in the differential diagnosis of heart block in children or young adults. This is the first case to be reported in Japan.Case report A 31 year old man was admitted to hospital because of poor appetite. On routine physical examination, a grade 2/6 systolic murmur was heard at the left sternal border. No cyanosis was noted. The liver was not palpable. Serum aspartate aminotransferase and alanine aminotransferase activities were 58 U/l and 29 U/I respectively. A liver biopsy showed a cirrhotic pattern, and he was diagnosed as having alcoholic cirrhosis.At night his heart rate fell to 30 beats/min, and an electrocardiogram showed 2:1 atrioventricular block with a narrow QRS complex (Fig. 1). His bundle electrograms were recorded using standard catheter techniques. The HV interval was normal (30 ms) and the AH interval prolonged (150 ms).

Successful Excision of a Cystic Tumor of the Atrioventricular Nodal Region

“…5 It is a rare primary cardiac tumor located in the region of the atrioventricular node. According to previous reports, [1][2][3]6 it can cause variable degrees of heart blockage, which gradually evolve to complete heart blockage. Moreover, ventricular tachycardia or fibrillation sometimes occurs in patients with this tumor.…”

“…It is controversial whether the cyst should be resected completely from the base of the IAS. However, because one complication of this tumor is sudden death as a result of ventricular tachycardia or ventricular fibrillation, 2,3,6 we believe that complete resection is essential, even if subsequent pacemaker implant is required.…”

“…It is thus important to consider the possibility of cystic tumor of the atrioventricular nodal region in patients with electrocardiographic evidence of heart block limited to the atrioventricular node (ie, with a narrow QRS), particularly in women. 2 This tumor is thought to be of embryologic origin and not a true neoplasm because of its benign histological appearance and invariable location in the atrioventricular area. The atrioventricular nodal region is an area of embryologic fusion, suggesting that either mesothelium or nearby foregut inclusion could be incorporated in it.…”

“…Moreover, ventricular tachycardia or fibrillation sometimes occurs in patients with this tumor. 2,3,6 Tumor size varies from 0.5 mm to 30 mm, and there is no relationship between size and the occurrence of lethal arrhythmia. It is thus important to consider the possibility of cystic tumor of the atrioventricular nodal region in patients with electrocardiographic evidence of heart block limited to the atrioventricular node (ie, with a narrow QRS), particularly in women.…”

Further evidence of nonasbestos-related mesothelioma. A review of the literature.

“…Although exposure to asbestos could not be excluded in some of them, most o f the cases appeared to be sponta neous. Other cases are as follow s: a single case in Sweden (5), two in Germany (10), and one in Japan (24). In one of the patients, asbestos was found in the lungs at autopsy.…”