Hypertrophic Cardiomyopathy (HCM)
Definition
Autosomal dominant structural cardiomyopathy characterised by asymmetric septal hypertrophy (septal:free-wall thickness ratio > 1.3) and microscopic myocyte disarray covering > 5 percent of the ventricular cross-section. Leading structural cause of sudden cardiac death in young athletes in the UK, Italy, and US autopsy series.
- Inheritance
- Autosomal dominant
- Diagnostic ratio
- Septal to free-wall thickness ratio greater than 1.3
- Microscopic marker
- Myocyte disarray over 5 percent of ventricular cross-section
- Clinical significance
- Leading structural cause of sudden cardiac death in young athletes
Common questions
Why is HCM particularly relevant to sudden death investigation in young, apparently healthy people?+
The condition can be clinically silent, with exertion during sport as the first trigger for a fatal arrhythmia, so autopsy measurement of septal thickness and histological search for myocyte disarray becomes essential when no other cause of death is evident.
Can HCM be missed on a standard autopsy weight and measurement alone?+
Yes, mild or non-obstructive forms can have only borderline wall thickness, so pathologists rely on the combination of gross wall measurements, the septal to free-wall ratio, and targeted histology of the septum to avoid a false negative.
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