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.

Keywords: athletes; cardiomyopathy; myocarditis; sport; sudden death.

Figure 1.

A 42-y-old martial art player presenting with frequent and coupled premature ventricular beats with right bundle branch block/superior axis morphology during exercise testing (A). The athlete experienced sustained ventricular tachycardia during follow-up (B). Contrast-enhanced cardiac magnetic resonance revealed a subepicardial/midmyocardial stria of late gadolinium enhancement involving the anterolateral, lateral, and inferolateral left ventricular wall (white arrows; C, D).

Figure 2.

A 23-y-old soccer player who suffered syncope during a match. Contrast-enhanced cardiac magnetic resonance revealed a subepicardial/midmyocardial stria of late gadolinium enhancement involving the lateral left ventricular wall (A). Twelve-lead ECG showed T-wave inversion in the inferolateral leads and premature ventricular beats (B). The patient received an ICD because of sustained ventricular tachycardia inducibility by programmed ventricular stimulation. After 13 months, he experienced an ICD shock on fast (tachycardia cycle length 200 ms) ventricular tachycardia while he was playing table tennis (C).

Figure 3.

Short-axis postcontrast cardiac magnetic resonance views of a 27-y-old rower with frequent premature ventricular beats with a left bundle branch block/inferior axis morphology (suggestive of right ventricular outflow tract origin) (A) and in a 31-y-old healthy marathon runner without arrhythmias (B) showing late gadolinium enhancement with a spotty pattern at the inferior insertion point of the right ventricular free wall to the interventricular septum (black arrows).

Figure 4.

A 18-y-old tennis player who underwent contrast-enhancement cardiac magnetic resonance for inferolateral T-wave inversion at baseline 12-lead ECG (A) and frequent ventricular ectopic beats with a right bundle branch block/superior axis at exercise testing (B). Cardiac magnetic resonance revealed subepicardial/midmyocardial late gadolinium enhancement with a stria pattern involving the inferolateral left ventricular wall (white arrows; C). During follow-up, he developed progressive left ventricular dysfunction that led to refractory heart failure and heart transplantation. Panoramic view of the inferolateral left ventricular wall of the removed heart showed extensive replacement-type fibrosis mostly in the subepicardial and midmural layers, with focal fatty infiltration (trichrome heidenhain stain; D). At higher magnification, the residual cardiomyocytes are hypertrophic and show dysmetric and dysmorphic nuclei, with cytoplasmic vacuolization: note the diffuse fibrosis and patchy fatty infiltration (hematoxylin–eosin stain; E).

Figure 5.

Long-axis (A and C) and short-axis (B and D) postcontrast cardiac magnetic resonance views of two 34-y-old identical twin brothers showing a subepicardial/midmyocardial stria of late gadolinium enhancement involving the lateral and inferolateral left ventricular wall (white arrows).

Figure 6.

A, Kaplan–Meier analysis for survival from major arrhythmic events (sudden death, cardiac arrest because of ventricular fibrillation, sustained ventricular tachycardia, or appropriate implantable cardiac defibrillator shock) in athletes with ventricular arrhythmias and late gadolinium enhancement (LGE), in athletes with ventricular arrhythmias and no LGE, and in controls (with or without spotty LGE). B, Kaplan–Meyer analysis for survival from major arrhythmic events in the subgroup of athletes with ventricular arrhythmias and LGE according to specific LGE patterns (stria vs spotty).