The electrocardiographic abnormalities in highly trained athletes compared to the genetic study related to causes of unexpected sudden cardiac death.

BACKGROUND

Electrocardiograms in elite endurance athletes sometimes show bizarre patterns suggestive of inherited channelopathies (Brugada syndrome, long QTc, catecholaminergic polymorphic ventricular tachycardia) and cardiomyopathies (arrhythmogenic right ventricular cardiomyopathy, hypertrophic cardiomyopathy) responsible for unexpected sudden cardiac death. Among other methods, genetic analyses are required for correct diagnosis.

OBJECTIVE

To correlate 12-lead electrocardiographic patterns suggestive of inherited channelopathies and cardiomyopathies to specific genetic analyses.

DESIGN

Prospective study (2004-2007) of screening 12-lead ECG tracings in standard position and higher intercostal spaces V1 to V3 precordial leads, performed in athletes and normal sedentary subjects aged match. Genetic analyses of subjects with ECG abnormalities suggested inherited channelopathies and cardiomyopathies.

SETTING

All cardiologic exams and electrocardiograms were performed at "Prof. Dr. C.C. Iliescu" National Institute of Cardiovascular Diseases (Bucharest, Romania). The genetic studies were done at "Mina Minovici" National Institute of Forensic Medicine (Bucharest, Romania).

PARTICIPANTS

347 elite endurance athletes (seniors--190, juniors--157), mean age of 20; 200 subjects mean age of 21, belonging to the control group of 505 normal sedentary population.

RESULTS

Seniors. RSR' (V1 to V3) pattern, in 45 cases (23.68%), 5 of them with questionable Brugada sign (elevated J wave and "coved" ST segment, < 2 mm in one lead, V1. Typically, Brugada 1 sign was found in one case (0.52%) with no SCN5A abnormalities. One athlete (0.52%) had normal ECG and exon1 SCN5A duplication. MRI confirmed three arrhythmic right ventricular cardiomypathy epsilon waves (1.57%), in one case. ST-segment elevation myocardial injury like in V1-V3 precordial leads in 34 athletes (17.89%). Genetic analyses-no gene mutations. Juniors. Upright J wave was found in 43 cases (27.38%). Convex ST segment elevation in V1-V3/V4, in 39 cases (24.84%). Bifid T wave with two distinct peaks was found in 39 cases (24.84%), 5 of them with mild prolonged QTc (0.48"-0.56") and KCN genes mutations. Nine (5.73%) of the elevated ST segment juniors had questionable Brugada sign, two of which with KCN (n=1) and SCN5A (n=1) gene mutations. Ajmaline provocative test was negative in 4 and was refused by 5 subjects.

CONCLUSION

Bizarre QRS, ST-T patterns suggestive of abnormal impulse conduction in the right ventricle, including the right outflow tract, associated with prolonged QTc interval in some cases were observed in highly trained endurance athletes. The genetic analyses, negative in most athletes, identified surprising mutations in SCN5A and KCN genes in some cases.