Intensive exercise is associated with an increase in left ventricular wall thickness (LVWT) and cavity size. In some cases, a doubt may occur between an athlete’s heart and hypertrophic cardiomyopathy (HCM), and genetic testing has been suggested in the diagnostic work-up. The aim of the study was to assess the accuracy and role of genetic testing to distinguish athlete’s heart from borderline HCM and make a decision regarding sport/professional activity.

We studied consecutive athletes (intensive sport>10 hours/ weeks; LVWT 12 to 16mm) with a suspicion of borderline HCM according to the clinical status and cardiac examinations. We studied the accuracy of local cardiac assessment versus expert referral center (blinded assessment) versus results of genetic testing (analysis of the 5 main sarcomeric genes). All cardiac assessments were performed according to ECG, echo, exercise test andcmR (when available) and were blinded to genetic results.

37 athletes (35 men) were enrolled, mean age: 28±12 years, mean LVWT was 13.6±1.2mm. A causative mutation was identified in 27% (10/37, in MYBPC3 / MYH7 / TNNI3 / MYL2 genes) of athletes: among these 10 subjects, 8 had a cardiac diagnosis od suspected HCM and 2 had a suspected diagnosis of athlete’s heart. Genetic testing rectified cardiac assessment in 5.4% of our population. Local cardiac evaluation suspected HCM in 70% (n=26, only 31% with a mutation) versus 46% (n=17, 47% with a mutation) in expert center (p=0.03). In subjects without identified genetic mutation, HCM was suspected in 67% of cases in local center versus 33% in expert center (p=0.01).

We report the first systematic evaluation of genetic testing in athletes with a suspicion of HCM. Genetic testing was able to confirm the diagnosis of HCM in 27%, including the rectification of cardiac assessment in 5.4%. Our results suggest that genetic testing may have a role in athletes with a suspicion of borderline HCM.