The clinical sequelae of cardiac sarcoidosis range from asymptomatic conduction abnormalities to fatal ventricular arrhythmias, depending upon the location and extent of granulomatous inflammation.
Complete heart block is the most common finding in patients with clinically evident cardiac sarcoidosis and is reported in 23–30% of patients.4
First degree heart block and bundle branch block also often occur, due to involvement of the basal septum by scar tissue or granulomas or the involvement of the nodal artery causing ischaemia in the conduction system.w11
Sarcoid granulomas in the ventricular myocardium can become foci for abnormal automaticity, increasing the likelihood of re‐entrant tachyarrhythmias. Ventricular tachycardia (VT) is the most frequent arrhythmia noted in cardiac sarcoidosis with a reported incidence of 23%.6
Roberts and colleagues found that sudden death caused by arrhythmia is the terminal event in 67% of sarcoid heart disease deaths.4
Supraventricular arrhythmias (for example, atrial flutter, fibrillation, and paroxysmal atrial tachycardia) may occur but are less common (15–17%). Atrial arrhythmias are mostly the result of atrial dilatation and/or pulmonary involvement rather than the result of atrial granulomas.4w11
Congestive heart failure is another manifestation and may be attributed to widespread infiltration of the myocardium, ventricular aneurysms, rhythm disturbances, cor pulmonale caused by pulmonary hypertension, valvar regurgitation, or a combination of these processes. Progressive congestive cardiac failure has been shown to be the cause of death in 25% of patients with cardiac sarcoidosis, making it the second most frequent cause of death, after sudden death.4w12
Other clinical manifestations of sarcoid heart disease include chest pain, electrocardiographic changes that may mimic transmural myocardial infarction, and pericardial abnormalities such as pericardial effusion, constrictive pericarditis, or even tamponade. Pericardial effusions are not uncommon (3–19%) in sarcoid, but rarely tend to tamponade.4w13