Hypertrophic Cardiomyopathy

Epidemiology

Signs and Symptoms

Investigations

Treatment

References

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Epidemiology and Natural History:

1. Autosomal dominant with heterogeneity and incomplete penetrance.

2. Family history known in 50%.

3. Some can run a benign course, but there is need to identify risk for adverse events.

4. Sudden cardiac death as high as 4-6% per year in children and adolescents, 1-2% per year in adults.

5. Death occurs as result of

· Sudden cardiac death in 51%. Usually young adults. ECG and ECHO cannot help stratify risk for this.

· Heart failure in 36%.

· Stroke in 13%. This is a result of atrial fibrillation

Signs and Symptoms:

1. Dyspnoea

2. Chest pain

3. Arrhythmias (palpitation)

4. Syncope

5. Sudden death

6. Systolic murmur changing with position

Investigations:

1. Chest X-ray is normal – the heart is hypertrophied (septum), but not dilated.

2. ECG normal in only 7% of all patients and 27% of asymptomatic patients. Abnormalities almost always increased LV voltage with tall QRS and ST depression. Usually precordial T wave inversion. 50% have a narrow Q in 1, AVL, V5, V6. Some will have Q waves in inferior leads (2, 3, AVF)

3. ECHO usually shows the septal hypertrophy with obstruction of LV outflow.

Treatment:

1. Medical treatment includes beta blockers or verapamil to attenuate the outflow gradient. Amiodarone is used in presence of supraventricular or ventricular arrhythmias.

2. While medical treatment may help symptoms, it has no effect on progression of the disease or on incidence of sudden cardiac death.

3. Surgical myomectomy occasionally used.

4. Inplantable defibrillators used in presence of known or recurring life-threatening ventricular arrhythmias.

References:

1. Unrecognized killers on ECG. Audio Digest Emergency Medicine 2007. 24(1)

2. UpToDate Ver. 14.2 2006. Natural history of hypertrophic cardiomyopathy.

3. UpToDate Ver. 14.2 2006. Clinical manifestations of hypertrophic cardiomyopathy.