To the Editor:

Much has been written on the potential dangers of sporting activities in children and young adults with potentially arrhythmogenic cardiac conditions. Current international guidelines recommend avoidance of strenuous activity and competitive sports in persons with these conditions.1 Children excluded from sports activities may seek alternative sources of entertainment and excitement, including electronic gaming, yet their safety in this context is not established.

We report four instances of syncope in three children due to ventricular tachycardia or ventricular fibrillation while playing electronic games. All four episodes occurred while the child was playing an electronic war game at home. The three children were male, 10 to 15 years of age. Patient 1 (10 years of age) suddenly lost consciousness after winning the electronic war game he was playing. He spontaneously regained consciousness. He subsequently received a diagnosis of catecholaminergic polymorphic ventricular tachycardia after a cardiac arrest due to ventricular fibrillation at school. Polymorphic ventricular ectopy was identified with the use of an intravenous adrenaline challenge, and genetic testing identified a variant (c.7600C→G, p.Leu2534Val) in the gene encoding ryanodine receptor 2 (RYR2), which is “likely pathogenic” according to American College of Medical Genetics and Genomics criteria. Patient 2 (15 years of age) had previously undergone the Rastelli procedure for d-transposition of the great arteries with ventricular septal defect. He suddenly became presyncopal sitting on his bed while winning the electronic war game he was playing. Rapid monomorphic ventricular tachycardia was diagnosed and successfully cardioverted in the emergency department. Invasive electrophysiological testing was unrevealing. An implantable cardioverter–defibrillator (ICD) was placed and metoprolol commenced. Two months later, he had another episode while playing the same game, again when about to win, with successful cardioversion by the ICD. Patient 3 (11 years of age) collapsed after having palpitations while animatedly playing an electronic war game with a friend. The stage of play at the time of collapse was not recollected. He spontaneously regained consciousness. His QT interval corrected for heart rate was 570 msec. A diagnosis of long-QT syndrome was established in the patient and, subsequently, in several family members. Two sudden unexplained deaths were identified in the family, and genetic testing is under way.

Electronic games have been shown to significantly increase the heart rate of participants.2,3 Mental stress and heightened emotion have been shown to shorten the ventricular action potential and are known triggers for cardiac arrhythmia, particularly in long-QT syndrome.1,4,5 Increases in sympathetic activation and adrenergic stimulation, mimicked here by the adrenaline challenge in Patient 1, are proposed as the mechanism for this phenomenon.

Claire M. Lawley, M.B., B.S.

University of Sydney, Sydney, NSW, Australia

[email protected]

Jonathan R. Skinner, M.B., Ch.B., M.D.

Starship Children’s Hospital, Auckland, New Zealand

Christian Turner, M.B., B.S.

Children’s Hospital at Westmead, Westmead, NSW, Australia

Disclosure forms provided by the authors are available with the full text of this letter at NEJM.org.