It has been shown by prospective studies that Rheumatic heart disease (RHD) is linked to the occurrence of carditis during the first episode of ARF. If the first episode is accompanied with carditis, the recurrences also manifest carditis. Around 40 per cent cases of ARF develop carditis and 66 per cent of ARF patients with carditis develop RHD on follow up. During carditis (which is always pancarditis), Carey-Coombs murmur of acute valvulitis is audible. Since mitral regurgitation is the commonest valvular lesion during ARF, one hears a pansystolic murmur and middiastolic flow murmur at mitral area. Basal early diastolic murmur due to aortic regurgitation may be audible. The pulmonary and tricuspid valves are rarely involved. Pericarditis, pericardial effusion and arrhythmias (1st and 3rd degree heart blocks) are other features of rheumatic carditis.

Pericarditis is diagnosed by characteristic chest pain, pericardial rub, typical ECG changes or presence of pericardial fluid on 2D-Echo. Myocarditis presents as tachycardia, distant heart sounds, heart enlargement or signs of congestive cardiac failure (CCF).