Myocarditis is an under-recognised cardiac disease which can present from asymptomatic form to acute pump failure with gross ECG changes
Myocarditis causes a diffuse, but patchy involvement of myocardium including atrium, ventricles and the conducting system.
ECG Presentation of Mocarditis:-
1. Abnormalities of QRS complex
- Increase in QRS duration
- Bizzare intaventricular conduction defects
- Pathological Q waves and loss of R wave amplitude
2. STE or STD
3. Low to inverted T waves in left oriented leads
4. AV block of first degree is more common than higher degree AV blocks
5. Prolonged QT interval
6. Arrhythmias like Sinus Tachycardia
Sinus tachycardia with non-specific ST segment changes
Widespread concave ST elevation (pericarditic changes) in a child with viral myocarditis.
Myocarditis as mimic of acute MI
Myocarditis may show ECG changes suggestive of acute myocardial ischaemia. ECG may show ST segment elevation in >/= 2 contiguous leads (54%) , T wave inversions (27%) , widespread ST segment depression (18%) and pathological Q waves (18%- 27%) .
While the QRS and ST segment abnormalities usually regress as the disease subsides , T wave inversion in the left precordial leads may remain for weeks and even months after the acute episode.
However, patients who have had severe myocarditis may continue to have persistent QRS and ST segment abnormalities , and arrhythmias reflecting permanent underlying myocardial damage.