The purpose of this observational study is to investigate whether myocardial scar characteristics assessed by cardiac magnetic resonance (CMR) can predict the risk of out-of-hospital sudden cardiac death (SCD) after myocardial infarction (MI). It aims to answer two primary questions:

What is the association between CMR-assessed myocardial scar and post-MI SCD? Can we develop an imaging-clinical multimodal risk score for post-MI SCD? Participants included in this study had previously undergone CMR imaging during the stable phase following their MI as part of their prior clinical care. Prognostic data for these participants are collected through clinic visits and telephone follow-up.

Sudden cardiac death (SCD) remains a leading cause of mortality post-myocardial infarction (MI). Current risk stratification relying primarily on left ventricular ejection fraction (LVEF ≤35%) for implantable cardioverter-defibrillator (ICD) therapy is inadequate, as many SCD events occur in patients with LVEF >35%. Myocardial scar characteristics assessed by cardiac magnetic resonance (CMR), particularly late gadolinium enhancement (LGE), show promise for improved arrhythmic risk prediction but require robust validation. This study aims to develop and validate a multimodal clinical-CMR risk prediction model integrating comprehensive scar characterization to better identify high-risk post-MI patients who may benefit from ICD therapy, optimizing prevention strategies and resource utilization.

This single-center, ambispective cohort study comprises two phases. Phase 1 (Retrospective): Patients treated for myocardial infarction (MI) at our institution between 2015 and 2025 were screened retrospectively. Those who underwent CMR imaging at least one month post-MI were included. Baseline clinical characteristics and detailed CMR findings were collected. Prognostic data for these patients were retrospectively gathered through January 2026.

Phase 2 (Prospective): Prospective collection of prognostic data for the enrolled cohort will continue from 2026 through 2036. Follow-up will be conducted primarily via clinic visits and telephone interviews at 6-month intervals.

Endpoint Definitions:

Primary Endpoint: Sudden cardiac death (SCD)-equivalent events, encompassing:

SCD events;Aborted SCD events (successful resuscitation from cardiac arrest or ventricular arrhythmia);Appropriate implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRT-D) therapies for terminating ventricular tachyarrhythmias.

Secondary Endpoints:

Include all-cause mortality, cardiovascular mortality, heart failure rehospitalization, recurrent myocardial infarction, and composite endpoints thereof.

Inclusion Criteria:

1. Age between 18 and 80 years.
2. Completion of cardiac magnetic resonance (CMR) imaging at Anzhen Hospital during the stable phase (≥1 month) following an acute myocardial infarction (MI).

Exclusion Criteria:

1. Prior implantation of an implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRT-D) before the index MI.
2. Pre-existing diagnosis of a primary arrhythmia syndrome (e.g., long QT syndrome, Brugada syndrome) before the index MI.
3. Concurrent end-stage disease (e.g., advanced malignancy) directly resulting in an estimated life expectancy of less than one year.
4. History of established non-ischemic cardiomyopathy (e.g., dilated, hypertrophic, or restrictive cardiomyopathy) before the index MI.
5. Significant concomitant valvular heart disease. Status post mechanical heart valve replacement.
6. Patients refuse to be followed up.

Chinese patients with myocardial infarction (MI).