A patient presented with fatigue,dyspnea and ankle edema.ECG shows the following picture.What can be the most probable diagnosis?
A. Hypertrophic Cardiomyopathy
B. Restrictive Cardiomyopathy
C. Dilated Cardiomyopathy
Ans:C. Dilated Cardiomyopathy.
ECG in the image shows:
- There is marked LVH (S wave in V2 > 35 mm) with dominant S waves in V1-4.
- Right axis deviation suggests associated right ventricular hypertrophy (i.e. biventricular enlargement).
- There is evidence of left atrial enlargement (deep, wide terminal portion of the P wave in V1).
- There are peaked P waves in lead II suggestive of right atrial hypertrophy (not quite 2.5mm in height).
- It is a myocardial disease characterised by ventricular dilatation and global myocardial dysfunction (ejection fraction < 40%).
- Patients usually present with symptoms of biventricular failure, e.g. fatigue, dyspnoea, orthopnoea, ankle oedema.
- Associated with a high mortality due to progressive cardiogenic shock or ventricular dysrhythmias (sudden cardiac death).
- Can be divided into ischaemic and non-ischaemic.
- Dilated cardiomyopathy commonly occurs following massive anterior MI due to extensive myocardial necrosis and loss of contractility.
- Most cases are idiopathic.
- Up to 25% are familial (primarily autosomal dominant, some types are X-linked) .
A very small proportion may occur with:
- Viral myocarditis (coxsackie B / adenovirus).
- Toxins (e.g. doxorubicin).
- Autoimmune disease.
- Pregnancy (peripartum cardiomyopathy).
Common ECG associations with DCM.
- The most common ECG abnormalities are those associated with atrial and ventricular hypertrophy —
- typically, left sided changes are seen but there may be signs of biatrial or biventricular hypertrophy.
- Interventricular conduction delays (eg. LBBB) occur due to cardiac dilatation.
- Diffuse myocardial fibrosis may lead to reduced voltage QRS complexes, particularly in the limb leads.
- There may be a discrepancy of QRS voltages with signs of hypertrophy in V4-6 and relatively low voltages in the limb leads.
- Left axis deviation.
- Poor R-wave progression with QS complexes in V1-4 (“pseudo-infarction” pattern).
Frequent ventricular ectopics and ventricular bigeminy (seen with severe DCM).
- Ventricular dysrhythmias (VT / VF).