<prompt> Answer this question truthfullyWhat is the relationship between diphtheria and an electrocardiogram?  <response>: <reason> An ECG in patients with diphtheria can be normal. However, in patients with diphtheria myocarditis, a wide range of abnormalities related to conduction and rhythm may be observed. Common ECG findings in cases of diphtheria myocarditis include: Prolonged PR or QT intervals Alterations in the ST segment, either elevation or depression Alterations in the T wave Atrioventricular block AV block Bundle branch block BBB Hemiblock Sinus bradycardia Arrythmias, such as supraventricular tachycardia SVT and ventricular tachycardia VT 