(2) The patient has marked hypodynamia, pale complexion, palpitation, short breath, chest distress, profuse sweat, dizziness, precordial pain, cold limbs, myodynia, etc. In infants, food refusal, cyanosis, cold limbs, periblepsis, etc. may occur.
(3) Auscultation of the heart shows increased heart rate, low and dull heart sounds, diminution of the first heart sound at the apex area of the heart. Gallop rhythm, premature beat, coupled rhythm or trigeminy exist. Apex area of the heart may have I to II degree systolic murmur.
(4) Laboratory examinations reveal quickened erythrocyte sedimentation rate, elevated serum creatine phosphokinase, serum aspartate transaminase, lactic dehydrogenase and its isoenzyme. A virus may be isolated from the nasopharynx, feces, serum and pericardial effusion at the early stage while the corresponding antibody to the virus in serum rises at the restoration stage.
(5) Electrocardiogram may show arrhythmia of varying degree, slightly depressed S -T segment and lower or inverted T-wave. X-ray film reveals spherical cardiomegaly and enlargement of every cardiac atrium and ventricle.