Exam Cram

• Hypertrophic obstructive cardiomyopathy is the commonest cause of sudden death during exercise in under 35yrs

• Genetic type of cardiomyopathy causing syncope by LV obstruction or ventricular fibrillation

• Diagnosis: ECHO

• Management: ICD

Outline

Background 

• Autosomal dominant inheritance, 60% have identifiable gene (MYH7)

• Left ventricle increases in size causing left ventricle dysfunction via obstruction and by developing ventricular arrhythmias: VT & VF

• Prevalence 0.2% worldwide

Assessment 

History:

• Syncope (exercise induced)

• Short of breath

• Palpitations

• Reduced exercise tolerance

• Family history of sudden death in young

Examination:

• Hard mid-systolic ejection murmur on left sternal edge

• Normal S1, split S2 and S3 (CHF) or S4 (LVH)

Investigations:

• ECG: left ventricular hypertrophy

• ECHO: left ventricle hypertrophy with outflow obstruction

• BNP elevated in CHF

Diagnosis

Diagnostic criteria: ECHO findings

Differentials: syncope in young: Brugada (at rest), LQTS (drug induced)

Management

1. ICD for episodes of VT

2. Betablockers if mildly symptomatic

3. Surgical intervention - symptoms of outflow obstruction failing to respond to medical management

   1. 1. Septal myomectomy (young)

      2. Septal ablation (old)

Med Reg Notes

Factors associated with sudden death:

• Degree of septal hypertrophy

Further Management

ICD responsible for largest reduction in mortality- terminating malignant tachyarrhythmias

Betablockers reduce LV outflow obstruction and reduce risk of ventricular arrhythmias. 

AF is common which may require anticoagulation. 

Reference and Resources

1. Basit H, Alahmadi MH, Rout P, et al. Hypertrophic Cardiomyopathy. [Updated 2024 Jun 7]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK430788/

Written in 2025