This ECG was taken from a 30-year old man who presented with exertional lightheadedness and palpitations.What can be the most probable diagnosis?
A. Hypertrophic Obstructive Cardiomyopathy
B. Dilated Cardiomyopathy
C. Restrictive Cardiomyopathy
Ans:A. Hypertrophic Obstructive Cardiomyopathy.
ECG in the image shows Dagger like Q waves marked by black arrow.
Hypertrophic cardiomyopathy (HCM)
- It is one of the most common inherited cardiac disorders (affecting ~ 1 in 500 people) and is the number one cause of sudden cardiac death in young athletes.
- The chief abnormality associated with HCM is left ventricular hypertrophy (LVH), occurring in the absence of any inciting stimulus such as hypertension or aortic stenosis.
- The most commonly observed pattern is asymmetrical thickening of the anterior interventricular septum (= asymmetrical septal hypertrophy).
- This pattern is classically associated with systolic anterior motion (SAM) of the mitral
- valve and dynamic left ventricular outflow tract (LVOT) obstruction.
- Exertional syncope or pre-syncope — this is the most worrying symptom, suggesting dynamic LVOT obstruction ± ventricular dysrhythmia, with the potential for sudden cardiac death.
- Symptoms of pulmonary congestion (e.g. exertional dyspnoea, fatigue, orthopnoea, paroxysmal nocturnal dyspnoea) due to left ventricular dysfunction.
- Chest pain — may be typical anginal pain due to increased demand (thicker myocardial walls) and reduced supply (aberrant coronary arteries).
- Palpitations due to supraventricular or ventricular arrhythmias.
- This relatively uncommon form of HCM is seen most frequently in Japanese patients (13-25% of all HCM cases in Japan).
- There is localised hypertrophy of LV apex, causing a “spade-shaped” configuration of the LV cavity on ventriculography.
- The classic ECG finding in apical HCM is giant T-wave inversion in the precordial leads.
- Left ventricular hypertrophy results in increased precordial voltages and non-specific ST segment and T-wave abnormalities.
- Asymmetrical septal hypertrophy produces deep, narrow (“dagger-like”) Q waves in the lateral (V5-6, I, aVL) and inferior (II, III, aVF) leads. These may mimic prior myocardial infarction, although the Q-wave morphology is different: infarction Q waves are typically > 40 ms duration while septal Q waves in HCM are < 40 ms. Lateral Q waves are more common than inferior Q waves in HCM.
- Left ventricular diastolic dysfunction may lead to compensatory left atrial hypertrophy, with signs of left atrial enlargement (“P mitrale”) on the ECG.
- Giant precordial T-wave inversions in apical HCM
- Signs of WPW (short PR, delta wave).
- Dysrhythmias: atrial fibrillation, supraventricular tachycardias, PACs, PVCs, VT