Why the study?
Sudden cardiac arrest can stem from acute reversible injury or chronic damage, and the prognostic role of cardiac magnetic resonance-detected myocardial edema on arrhythmic outcomes required evaluation.
Does the presence of myocardial edema on early cardiac magnetic resonance imaging predict arrhythmic outcomes in survivors of out-of-hospital cardiac arrest?
Does the presence of myocardial edema on early cardiac magnetic resonance imaging predict arrhythmic outcomes in survivors of out-of-hospital cardiac arrest?
The presence of myocardial edema on early cardiac magnetic resonance imaging in survivors of out-of-hospital cardiac arrest predicts a favorable long-term arrhythmic outcome with fewer appropriate ICD interventions.
Myocardial edema may mark lower arrhythmic risk after OHCA; leaves open whether early CMR should guide ICD decisions.
Background Sudden cardiac arrest (SCA) may be caused by an acute and reversible myocardial injury, a chronic and irreversible myocardial damage, or a primary ventricular arrhythmia. Cardiac magnetic resonance imaging may identify myocardial edema (ME), which denotes acute and reversible myocardial damage. We evaluated the arrhythmic outcome of SCA survivors during follow-up and tested the prognostic role of ME. Methods and Results We included a consecutive series of 101 (71% men, median age 47 years) SCA survivors from 9 collaborative centers who underwent early (<1 month) cardiac magnetic resonance imaging and received an implantable cardioverter-defibrillator (ICD). On T2-weighted sequences, ME was found in 18 of 101 (18%) patients. According to cardiac magnetic resonance imaging findings, the arrhythmic SCA was ascribed to acute myocardial injury (either ischemic [n=10] or inflammatory [n=8]), to chronic structural heart diseases (ischemic heart disease [n=11], cardiomyopathy [n=20], or other [n=23]), or to primarily arrhythmic syndrome (n=29). During a follow-up of 47 months (28 to 67 months), 24 of 101 (24%) patients received an appropriate ICD intervention. ME was associated with a significantly higher survival free from both any ICD interventions (log-rank=0.04) and ICD shocks (log-rank=0.03) and remained an independent predictor of better arrhythmic outcome after adjustment for left ventricular ejection fraction and late gadolinium enhancement. The risk of appropriate ICD intervention was unrelated to the type of underlying heart disease. Conclusions ME on early cardiac magnetic resonance imaging, which denotes an acute and transient arrhythmogenic substrate, predicted a favorable long-term arrhythmic outcome of SCA survivors. These findings may have a substantial impact on future guidelines on the management of SCA survivors.
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A 2021 study studied this question.