Identification of the potentially arrhythmogenic substrate in the acute phase of ST-segment elevation myocardial
Diego Penela1, Juan Acosta1, David Andreu1
1Hospital Clínic and IDIBAPS (Institut d'Investigació Agustí Pi i Sunyer), Barcelona, Catalonia, Spain.
Insights
The potentially arrhythmogenic substrate after ST-segment elevation myocardial infarction (STEMI) is established within the first week. Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) can identify this substrate early, even as scar mass reduces over six months.
Area of Science:
- Cardiology
- Medical Imaging
- Cardiac Electrophysiology
Background:
- Predicting sudden cardiac death risk after ST-segment elevation myocardial infarction (STEMI) is clinically challenging.
- Identifying the arrhythmogenic substrate post-STEMI is crucial for risk stratification.
Purpose of the Study:
- To evaluate the utility of late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) in identifying the arrhythmogenic substrate after STEMI.
- To assess the temporal evolution of this substrate over six months.
Main Methods:
- 100 patients with first STEMI underwent 3D LGE-CMR at 7 and 180 days.
- Left ventricular segments were analyzed for scar core and border zone (BZ) distribution.
- BZ channels were characterized in 5 myocardial layers.
Main Results:
- Scar mass significantly reduced from day 7 to 180 (22.6g to 13.8g).
- 89% of BZ channels remained consistent in location and morphology at 6 months.
- Early LGE-CMR (day 7) showed 96% sensitivity and 90% specificity for predicting 6-month BZ channels.
Conclusions:
- The arrhythmogenic substrate is established within the first week post-STEMI.
- LGE-CMR can reliably identify this substrate early, which persists despite scar reduction.
- Early identification of BZ channels aids in risk stratification for sudden cardiac death.
Background:
Predicting sudden cardiac death risk in the first months after ST-segment elevation myocardial infarction (STEMI) remains challenging.
Objective:
The purpose of this study was to investigate the ability of late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) to identify the potentially arrhythmogenic substrate and its temporal evolution after STEMI.
Methods:
One hundred consecutive patients with a first STEMI were included. Three-dimensional high-resolution LGE-CMR was obtained at 3 T on days 7 and 180. Left ventricular wall was segmented and characterized by pixel signal intensity algorithm in 5 layers from endocardium to epicardium. A 3-dimensional color-coded shell map was obtained for each layer, depicting scar core and border zone (BZ) distribution. Presence and characteristics of BZ channels were registered for each layer.
Results:
At 180 days, left ventricular ejection fraction had improved significantly (from 46.7% ± 10% to 51.5% ± 10%; P <.001) and scar mass was reduced (from 22.6 ± 20 g to 13.8 ± 12 g; P <.001). Most BZ channels (89%) were identified in the same myocardial layer and American Heart Association (AHA) segment, with the same orientation and morphology in both studies. Early LGE-CMR had 96% sensitivity and 90% specificity for predicting presence of BZ channels at 180 days. Greater presence was observed in patients with no-reflow phenomenon at baseline (P = .01).
Conclusion:
Most BZ channels can be identified by LGE-CMR at day 7 post-STEMI and, despite scar mass reduction, remain unaltered at 6 months, suggesting that the potentially arrhythmogenic substrate is established within the first week post-STEMI.
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