Nonischemic Left Ventricular Scar as a Substrate of Life-Threatening Ventricular Arrhythmias and Sudden Cardiac Death in Competitive Athletes

Abstract

Background—The clinical profile and arrhythmic outcome of competitive athletes with isolated nonischemic left ventricular (LV) scar as evidenced by contrast-enhanced cardiac magnetic resonance remain to be elucidated.Methods and Results—We compared 35 athletes (80% men, age: 14–48 years) with ventricular arrhythmias and isolated LV subepicardial/midmyocardial late gadolinium enhancement (LGE) on contrast-enhanced cardiac magnetic resonance (group A) with 38 athletes with ventricular arrhythmias and no LGE (group B) and 40 healthy control athletes (group C). A stria LGE pattern with subepicardial/midmyocardial distribution, mostly involving the lateral LV wall, was found in 27 (77%) of group A versus 0 controls (group C; P<0.001), whereas a spotty pattern of LGE localized at the junction of the right ventricle to the septum was respectively observed in 11 (31%) versus 10 (25%; P=0.52). All athletes with stria pattern showed ventricular arrhythmias with a predominant right bundle branch block morphology, 13 of 27 (48%) showed ECG repolarization abnormalities, and 5 of 27 (19%) showed echocardiographic hypokinesis of the lateral LV wall. The majority of athletes with no or spotty LGE pattern had ventricular arrhythmias with a predominant left bundle branch block morphology and no ECG or echocardiographic abnormalities. During a follow-up of 38±25 months, 6 of 27 (22%) athletes with stria pattern experienced malignant arrhythmic events such as appropriate implantable cardiac defibrillator shock (n=4), sustained ventricular tachycardia (n=1), or sudden death (n=1), compared with none of athletes with no or LGE spotty pattern and controls.Conclusions—Isolated nonischemic LV LGE with a stria pattern may be associated with life-threatening arrhythmias and sudden death in the athlete. Because of its subepicardial/midmyocardial location, LV scar is often not detected by echocardiography.

Ventricular Arrhythmias in Young Competitive Athletes: Prevalence, Determinants, and Underlying Substrate

“…All 3 athletes exhibited arrhythmias with a RBBB configuration, which was concordant with the LV location of LGE, whereas CMR was negative in all athletes with LBBB arrhythmias and control athletes. These findings are in agreement with previous studies showing that a RBBB‐like morphologic feature of VA, but not LBBB, predicts the presence of an underlying LV scar 20, 25. Moreover, in athletes showing VA with a LBBB morphologic feature, no abnormalities of the right ventricle were evidenced by both echocardiography and CMR using dedicated morphofunctional and postcontrast views.…”

“…The clinical relevance of this finding is that nonischemic LV scar is an increasingly reported cause of life‐threatening VAs and SCD in the athletes, often undetected by routine electrocardiographic and echocardiographic screening 1, 20. However, this perspective is based on previous observations on selected athletes who were referred to tertiary center or experienced cardiac arrest.…”

“…However, some at‐risk arrhythmogenic diseases, such as focal myocarditis, early/minor cardiomyopathy, and segmental nonischemic LV scar, may be associated with a normal ECG 1, 20, 23, 24. Our study is unique in that ambulatory electrocardiographic monitoring used a 12‐lead configuration system: that offers the potential to increase the screening sensitivity for identification of these ECG‐undetectable concealed arrhythmic substrates by showing not only the presence but also the morphologic features of VAs.…”

Sudden cardiac death in young people and athletes

“…The reason is that the fibro-fatty scarring process predominantly involves the sub-epicardial and mid-mural myocardial layers, which contribute less to ventricular contraction, and the disease lesion can only be identified in the form of late gadolinium enhancement using contrast-enhanced cardiac magnetic resonance imaging. 48 Not surprisingly, the incidence of SD in patients with the classic ARVC variant has markedly decreased since the introduction of ECG preparticipation screening, while the difficultto-diagnose left dominant variant is now an increasingly emergent substrate at post-mortem. 49,50 Competitive sports increase the risk of SD by 5-fold in adolescent and young adults with ARVC.…”

Clinically suspected myocarditis with pseudo-infarct presentation: the role of endomyocardial biopsy

“…In addition, in acute onset myocarditis associated with systemic immune-mediated disease a prompt clinical management is life-saving (1,3,4). Moreover, even when remission spontaneously ensues and ventricular function is apparently restored, the acute inflammatory event, regardless of its infectious or immunemediated etiology, may still lead to long-term ventricular dysfunction or arrhythmogenicity (e.g., non-ischemic ventricular scars) (18). This raises the question whether an aetiology-directed therapy in the acute phase may promote "restitutio ad integrum", preventing formation and maintenance of irreversible arrhythmia and heart failure myocardial tissue substrates.…”