Effects of Atrial Ischemia on Left Atrial Remodeling in Patients with ST-Segment Elevation Myocardial Infarction
Jose M Montero-Cabezas1, Rachid Abou1, Surenjav Chimed1
1Department of Cardiology, Leiden University Medical Center, Leiden, the Netherlands.
Insights
Impaired coronary flow in the dominant coronary atrial branch (CAB) after ST-segment elevation myocardial infarction (STEMI) leads to adverse left atrial (LA) remodeling. Reduced LA strain occurs before anatomical changes, indicating early atrial dysfunction.
Area of Science:
- Cardiology
- Cardiac Imaging
- Myocardial Infarction Research
Background:
- Adverse left atrial (LA) remodeling post-ST-segment elevation myocardial infarction (STEMI) is linked to poor prognosis.
- Impaired flow in the dominant coronary atrial branch (CAB) may cause significant LA myocardial damage and remodeling.
Purpose of the Study:
- To evaluate echocardiographic LA remodeling in STEMI patients with impaired dominant CAB flow.
- To investigate the relationship between dominant CAB flow impairment and LA structural and functional changes.
Main Methods:
- Retrospective comparison of 69 STEMI patients with impaired dominant CAB flow (Thrombolysis In Myocardial Infarction flow grade < 3) against 138 controls with normal flow.
- Echocardiographic assessment of LA remodeling, including LA volume, LA strain (speckle-tracking), and total atrial conduction time (Doppler tissue imaging) at baseline, 6, and 12 months.
Main Results:
- Patients with impaired dominant CAB flow showed higher peak troponin T.
- Larger LA maximal volumes and longer total atrial conduction times were observed at 6 months in the impaired flow group, persisting at 12 months.
- Significantly lower LA strain parameters (reservoir, conduit, booster) were evident from baseline and sustained throughout follow-up.
Conclusions:
- Atrial ischemia from impaired dominant CAB flow in STEMI patients is associated with adverse LA anatomic and functional remodeling.
- Reduced LA strain is an early indicator, preceding LA anatomic remodeling in the initial phases post-STEMI.
Background:
Adverse left atrial (LA) remodeling after ST-segment elevation myocardial infarction (STEMI) has been associated with poor prognosis. Flow impairment in the dominant coronary atrial branch (CAB) may affect large areas of LA myocardium, potentially leading to adverse LA remodeling during follow-up. The aim of this study was to assess echocardiographic LA remodeling in patients with STEMI with impaired coronary flow in the dominant CAB.
Methods:
Of 897 patients with STEMI, 69 patients (mean age, 62 ± 11 years; 83% men) with impaired coronary flow in the dominant CAB (defined as Thrombolysis In Myocardial Infarction flow grade < 3) were retrospectively compared with an age- and sex-matched control group of 138 patients with normal dominant CAB coronary flow.
Results:
Patients with dominant CAB-impaired flow had higher peak troponin T (3.9 μg/L [interquartile range, 2.2-8.2 μg/L] vs 3.2 μg/L [interquartile range, 1.5-5.6 μg/L], P = .009). No differences in left ventricular ejection fraction or mitral regurgitation were observed between groups at baseline or at follow-up. LA remodeling assessment included maximum LA volume, speckle-tracking echocardiography-derived LA strain, and total atrial conduction time assessed on Doppler tissue imaging at baseline, 6 months, and 12 months. Patients with dominant CAB-impaired flow presented larger LA maximal volumes (26.9 ± 10.9 vs 18.1 ± 7.1 mL/m2, P < .001) and longer total atrial conduction time (150 ± 23 vs 124 ± 22 msec, P < .001) at 6 months, remaining unchanged at 12 months. However, all LA strain parameters were significantly lower from baseline (reservoir, 20.3 ± 10.1% vs 27.1 ± 14.5% [P < .001]; conduit, 9.1 ± 5.6% vs 12.8 ± 8% [P < .001]; booster, 9.1 ± 5.6% vs 12.8 ± 8% [P < .001]), these differences being sustained at 6- and 12-month follow-up.
Conclusions:
Atrial ischemia resulting from impaired coronary flow in the dominant CAB in patients with STEMI is associated with LA adverse anatomic and functional remodeling. Reduced LA strain preceded LA anatomic remodeling in early phases after STEMI.
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