A COMPLEX CASE OF EARLY ONSET ATRIAL FIBRILLATION IN AN ENDURANCE ATHLETE: THE IMPORTANCE OF FAMILY HISTORY

Abstract

Abstract Introduction Early onset atrial fibrillation (AF) in an endurance athlete represents a challenge for the cardiologist, especially in apparent absence of an overt structural heart disease. Different genetic variants have been associated with early onset AF but indications to genetic testing are still under definition. Case A 54–year–old man (BMI 19 kg/sqm), previous competitive athlete (Nordic running and walking) presented to the Emergency Department with sudden onset palpitations and dyspnea due to high penetrance AF (145 bpm). Family history (FH) was positive for cerebrovascular accidents in both parents and for early onset (<60 years) AF in the father. The man had a recent history of borderline hypertension, of effort related syncope of and of infundibular, isolated, premature ventricular complexes during a maximal exercise stress test (otherwise negative for ischemia) which ultimately led to the denial of competitive sport eligibility. Sinus rhythm (SR) was acutely restored with flecainide and the patient was discharged with low dose nadolol. Cardiac US showed normal left ventricular (LV) dimensions and thicknesses (10 mm), with regular LVEF (60%) and global longitudinal strain (–18%), mildly dilated left atrium (LAVI 36 ml/sqm) and bi–leaflet mitral valve prolapse without significant mitral regurgitation, mitro–anular disjunction nor Pickelhaube sign; 24h Holter ECG showed SR with rare supraventricular (SV) ectopic beats and a 4 beats SV run. Due to the recurrence of short episodes of palpitations, rhythm control with flecainide and antithrombotic prophylaxis were started and AF ablation was planned. Genetic testing for early onset AF identified a nonsense variant (c.84665delG; p.Gly28222fs*2) in TTN gene, classified as likely pathogenic (C4), so far not reported in scientific literature. Also, despite a moderate–low cardiovascular risk as assessed by SCORE2, mostly due to the FH and the desire to engage in high intensity exercise, coronary CT was prescribed, which showed a critical coronary disease leading to stenting on left anterior descending artery and intermediate branch. Cardiac MRI was planned. Conclusions Early onset AF in endurance athletes should not be underrated and a thorough examination including a detailed family history should be performed. TTN is the single gene most frequently associated with early onset AF in absence of an overt structural heart disease, but the subsequent clinical evolution is still largely unknown.