ECG CME FEBRUARY 2026 (0.5 CME Points) (#f8b62d)

History:  This 38 year old man came for routine medical check up. His past health was good. Blood pressure was 125/80 mmHg. This is his ECG. *Please note that the voltage of V3-V6 was half.

Question:

What is the ECG diagnosis?

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Answer to December 2025 Issue’s CME

ECG diagnosis: Complete left bundle branch block.

Reason for the ECG diagnosis:

• QRS complex is widened to 0.14 seconds (normal <0.12).

• The QRS complexes at leads I, II, aVL, V5-V6 are slightly notched and showed somewhat "M" shape pattern.

• Absence of septal Q wave in leads V4-V6.

• Absence of R wave in V1.

• Please note that the QRS axis is usually normal in left bundle branch block. Sometimes the axis is indeterminate. The axis of this ECG is +15° (normal axis -30° to +90°).

• Non-specific ST segment depression and T wave inversion may occur at left side leads (I, aVL, V6).

Possible aetiology:

Always indicate underlying organic heart disease.

• Ischemic heart disease (commonest).

• Valvular heart disease in particular aortic valve disease.

• Cardiomyopathy.

• Congenital heart diseases.

• Myocarditis.

Significance:

It depends on the underlying etiology.

Principle of management:

Look for underlying heart disease from history and physical examination. If in doubt, further simple non-invasive investigations would include chest x-ray, echocardiography.

Exercise stress test is not indicated because of false positive result in complete left bundle branch block. If ischemia heart disease is suspected, consider cardiac magnetic resonance imaging (cardiac MRI) which is non-invasive and diagnostic, or CT coronary angiography.

Treat underlying organic heart disease if found.

Management of this patient:

Echocardiography for this patient showed enlarged left atrium, left ventricle and right ventricle. Left ventricular contraction was also globally impaired. Cardiac MRI did not reveal any myocardial ischemia. He was managed as a case of dilated cardiomyopathy.