Left Atrial Fibrosis in Atrial Fibrillation

Study Questions:

Is the extent of left atrial (LA) fibrosis associated with the risk of major adverse cardiovascular and cerebrovascular events (MACCE) in patients with atrial fibrillation (AF)?

Methods:

This was a retrospective analysis of 1,228 patients with AF who underwent cardiac magnetic resonance imaging with late gadolinium enhancement (LGE). LGE was categorized based on its extent using a grading system of I (<10%) to IV (≥30%). The primary outcome of the study was the incidence of MACCE, defined as a composite of ischemic stroke/transient ischemic attack (TIA), myocardial infarction, acute heart failure, and cardiovascular death. The median duration of follow-up was 2.8 years.

Results:

Stage I LGE was present in 34.5% of patients, stage II in 41.4%, stage III in 19.1%, and stage IV in 4.9%. Older age and female sex were associated with stage IV LGE and paroxysmal AF was associated with stage I. The CHA2DS2-VASc score correlated with the LGE stage. During 5 years of follow-up, a MACCE occurred in 16.4% of patients. After adjusting for comorbidities, LGE was independently associated with the MACCE outcome (hazard ratio [HR], 1.67 for stage IV vs. I). However, the only component of the MACCE composite that was associated with LGE was stroke/TIA (HR 3.9 for stage IV vs. I).

Conclusions:

The extent of LA LGE is associated with the risk of stroke/TIA in patients with AF.

Perspective:

The results of this study suggest that the extent of LA fibrosis may be an independent risk factor for stroke in patients with AF. An important clinical implication of this finding is that patients with AF and extensive fibrosis may be at ongoing risk of stroke even if sinus rhythm is restored by drug therapy or ablation.

Clinical Topics: Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Noninvasive Imaging, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure, Magnetic Resonance Imaging

Keywords: Arrhythmias, Cardiac, Atrial Fibrillation, Cardiac Imaging Techniques, Fibrosis, Gadolinium, Heart Atria, Heart Failure, Ischemic Attack, Transient, Magnetic Resonance Imaging, Myocardial Infarction, Risk Factors, Stroke


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