The heart in Wegener's granulomatosis

Associate Editor:

Overview
Cardiac involvement in Wegener's granulomatosis is not as uncommon as generally thought, and ranges in prevalence from 6 to 44% of patients. It may take many forms and varies from the principal clinical manifestation of the disease to a mild or subclinical manifestation of the disease. Cardiac involvement should be actively sought in patients with Wegener's granulomatosis and should be considered in patients with non specific illness.

Pericarditis
Pericarditis and effusion have been reported either as the sole manifestation of the disease or in conjunction with other cardiac abnormalities. Pericardial involvement may be found unexpectedly on postmortem examination, it may present acutely as tamponade or it may present as chronic constrictive pericarditis. In a some cases, pericarditis may not be a primary manifestation of the disease but may be a secondary manifestation due to myocardial infarction or uremia due to renal involvement.

Arteritis
Generalized arteritis may be associated with a systemic illness with fever, malaise, and weight loss, which may mimic infective endocarditis. A more localized form of arteritis has also been recognized, which affects for instance the coronary arteries and may produce coronary artery stenoses, myocardial infarction and even death in rare cases.

Aortitis
Inflammation may also involve the aorta both proximally, causing dilatation and distally, causing retroperitoneal inflammation. Diagnosing of proximal aortic involvement was previously noted at postmortem examination before newer imaging modalities as MSCT, MRI and transesophageal echocardiography.

Myocarditis
Myocarditis with granulomata can be associated with acute congestive heart failure. It may later progress to cardiomyopathy. The carditis may also affect the atria or produce mass lesions within the ventricles. These in turn may result in arrhythmia or obstruction. Some patients develop both a tachyarrhythmia and a detectable gradient across the left ventricular outflow tract.

To date few patients with a cardiac mass due to Wegener's granulomatosis have undergone surgical resection, although appropriate chemotherapy may induce regression of the mass.

Valvulitis
Valve abnormalities may occur secondary to dilatation of the aortic root or left ventricle, but primary valvulitis has also been reported. It occurs both alone and as part of either widespread endocarditis or pancarditis. This form of the disease may result in a mistaken diagnosis of culture negative infective endocarditis which fails to respond to antibiotic therapy and may delay the initiation of appropriate and potentially lifesaving treatment.

Cardiac Arrhythmias
Conduction abnormalities have been reported, possibly as a result of granuloma involving the conduction system or arteritis of the atrioventricular nodal artery. All degrees of conduction defect are recognized, from intraventricular conduction delays through first and second degree heart block to complete heart block. These may require permanent pacing but will occasionally respond to pharmacotherapy.

The most common arrhythmias are atrial tachycardia and atrial fibrillation or flutter. Ventricular arrhythmia has been noted in association with dilated cardiomyopathy, ischemia and secondary to cardiac masses.