The electrocardiogram and the phenotypic expression of hypertrophic cardiomyopathy

Extract

Hypertrophic cardiomyopathy (HCM) is a heterogeneous cardiac disease with respect to clinical expression and natural history, with sudden cardiac death (SCD) representing the most devastating complication in young individuals, including athletes.^{1  ,  2} At present, both American and European recommendations advise precautionary disqualification from most competitive sport in young patients with unequivocal diagnosis of HCM.^3–5

Diagnosis of HCM may be difficult in the clinical practice. According to guidelines, diagnosis is confirmed ‘In an adult, by a wall thickness ≥15 mm in one or more LV myocardial segments—as measured by any imaging technique [echocardiography, cardiac magnetic resonance imaging (CMR), or computed tomography]—that is not explained solely by loading conditions’.² However, not infrequently HCM presents with lesser degrees of wall thickening, especially in young athletes (i.e. LV wall thickness of 13–14 mm), ‘in these cases, the diagnosis of HCM requires evaluation of other features, including family history, non-cardiac symptoms and signs, electrocardiogram (ECG) abnormalities, laboratory tests, and multi-modality cardiac imaging’.² Eventually, strong support to the diagnosis (especially in the context of a family screening) is made by the identification of a definite causative genetic mutation, being HCM inherited as an autosomal dominant disease.^{1  ,  2} The relevance of a causative gene anomaly in the setting of HCM diagnosis, however, is limited in the absence of phenotype, and the simple identification of gene mutation in families with genetic forms of HCM does not represent, per se, a sufficient criterion for diagnosis.²