BACKGROUND Sarcoidosis is a multisystem inflammatory disease of unknown cause. Due to its protean and nonspecific clinical manifestations, the optimal diagnostic and therapeutic strategies, as well as prognosis, are not well defined. OBJECTIVE To review the literature on sarcoid heart disease and present an approach to its diagnosis, prognosis and therapy. METHODS MEDLINE and PreMEDLINE searches of all available English-language articles and case reports from 1966 to 2002 were performed. Search terms included 'sarcoidosis' and 'heart diseases', with a variety of medical subject subheadings. RESULTS Clinical disease often includes heart block, dilated cardiomyopathy and ventricular arrhythmias. Patients with sarcoidosis are at increased risk of sudden death. Because the yield of endomyocardial biopsy for definitive diagnosis is low, the diagnosis is often made with a combination of electrocardiography, Holter monitoring, echocardiography, myocardial perfusion imaging and, most recently, magnetic resonance imaging. For symptomatic patients, medical therapy may include a trial of steroids and immunosuppressive therapy. Monoclonal antibodies against tumour necrosis factor may be employed in refractory cases. Heart block warrants a permanent pacemaker, while ventricular tachyarrhythmias are typically amiodarone-unresponsive, requiring implantation of an implantable cardioverter defibrillator. CONCLUSIONS Although there are no large, randomized trial data on cardiac sarcoidosis, the literature suggests that making the diagnosis is clinically important. Unlike the situation in isolated pulmonary disease, cardiac involvement implies a poor prognosis. The diagnosis often requires high clinical suspicion with a combination of radiological and nuclear imaging. Therapy with steroids may halt progression of left ventricular dysfunction, while arrhythmias warrant device therapy.