Symptomless myocarditis and myalgia in viral and Mycoplasma pneumoniae infections

Of i8 patients admitted to hospital with proved viral (influenza A, echo-9 and -30) or Mycoplasma pneumoniae infections, 6young adults between I5 and27years showed electrocardiographic evidence ofsymptomless myocarditis, which was invariably associated with myalgia. Myalgia is an important symptom presaging myocarditis and is an indication for an early electrocardiogram in all patients with suspected viral infections, despite the absence of cardiac symptoms or signs. M. pneumoniae myocarditis, we believe, was reported by us for the first time (Lewes and Rainford, I970). Cardiographic signs, commonly maximal over the right ventricular surface leads, persisting for 2 to 14 days and occasionally for many months, may closely mimic coronary artery disease, septal cardiac infarction, or pulmonary embolism. Correct electrocardiographic interpretation is essential if unwarranted cardiac invalidism is to be avoided, particularly in young patients with an indefinite history of infection and in those with protracted abnormalities in the electrocardiogram.