Isolated Nonischemic Left Ventricular Scar in Asymptomatic Athletes: Clinical Characteristics, Genetic Background, and Follow-Up

Isolated nonischemic left ventricular scar (NILVS), identified by cardiac magnetic resonance, is an increasing finding in athletes and may be the substrate for life-threatening arrhythmias. Clinical significance in asymptomatic athletes is yet to be investigated.

This study sought to describe the clinico-genetic profile and follow-up of asymptomatic athletes diagnosed with NILVS through preparticipation screening.

We evaluated 40 athletes (90% males, 44 [range:33-52] years) including 9 elites, with isolated NILVS involving at least 2 segments, no previous major arrhythmic events, with available genetic testing and >1 year of follow-up. Data regarding electrocardiography, echocardiography, 24-hour Holter, exercise testing, and genetic analysis were collected. Follow-up assessed therapy, sport participation, and outcome.

Electrocardiogram abnormalities were present in 48%, and all showed premature ventricular beats at exercise testing, mostly with right bundle branch/superior axis morphology. Left ventricular ejection fraction was normal or mildly reduced. Genetic testing or family screening was positive in 9 (23%). Athletes without familial/genetic background were older and declared higher cumulative years of sports activity. Over a median follow-up time of 23 months, 84% continued noncompetitive sport, mostly (73%) on beta-blocker therapy. Two major arrhythmic events occurred (resuscitated cardiac arrest and sustained ventricular tachycardia), both in athletes with a positive family history for NILVS, but negative genetic testing, and both during noncompetitive exercise.

NILVS in asymptomatic athletes may carry arrhythmic risk even in the absence of previous symptoms or left ventricular dysfunction. Athletes with NILVS and no gene mutations/family history are older and with a higher past exercise volume.