Hypertrophic cardiomyopathy (HCM) has a sarcomeric origin in more than half of cases. Correlations between a mutation presence and the clinical, electrical and echocardiographic phenotype are not clearly characterised.

To determine the link for HCM patients between the genotype/phenotype, and the impact of a found mutation.

We studied a group of 104 patients with a HCM diagnosis (average age: 56±15 years). Clinical, echocardiographic, electrocardiographic as well as genetic data were evaluated and compared.

Genotype-positive patients were more likely to be younger (50,9±17.5 years versus 39,9±17.6, P<0.01), more often women (56% versus 27%, P<0.01), had more family history of hypertrophic cardiomyopathy (51% versus 18%, P<0.001) and an increased incidence of sudden death (2,99±2,83 versus 1,97±1,2, P=0.03). Echocardiographically, they were less often obstructive (P<0.01) and had a reduced left ventricular ejection function (P=0.02). Electrically, there was no difference in left ventricular hypertrophy ECG variables or in repolarization problems between the two groups.

Genotype-phenotype link for HCM patients is low and both the ECG and the echocardiography are not relevant. The presence of a mutation is associated with an increased risk of sudden death. Genetic testing for HCM patients remains essential considering the impact of non-genetic factors.