Impact of left atrial appendage fibrosis on atrial fibrillation in patients following coronary bypass surgery

Figures

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  Figure 1. Flowchart of patient selection. A total of 164 CABG‐patients were propensity matched, resulting in a total cohort of 43 patients with AF and SR. Subgroup division was based on mitral valve regurgitation. AF, atrial fibrillation; CABG, coronary artery bypass graft; LAA, left atrial appendage; MR, mitral valve regurgitation; SR, sinus rhythm

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  Figure 2. Digital segmentation of the left atrial appendage landscape. The Masson‐Goldner trichrome stained left atrial appendage (LAA) was segmented into superpixels via algorithm‐based classification. (A, B) present myocardiocytes (violet) and interstitial fibrosis (green). (C, D) exhibit identical tissue sections with algorithm‐detected interstitial fibrosis (lime‐green) and nonfibrotic areas (blue). (B, D) are selected magnified sections of (A) and (C) displaying the level of precision of the algorithm‐based segmentation

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  Figure 3. Interstitial fibrosis of the LAA in CABG patients with AF and SR. No significant difference in interstitial fibrosis was observed between the main propensity matched patient groups. Possibly, the underlying coronary heart disease, low to moderate grade mitral‐valve regurgitation and inclusion of paroxysmal AF reduce fibrotic contrast between both groups. Abbreviations: AF, atrial fibrillation; CABG, coronary artery bypass graft; LAA, left atrial appendage; SR, sinus rhythm

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  Figure 4. Interstitial fibrosis of the LAA in CABG patients with subgroups SR, SR + MR, AF, AF + MR. Consideration of mitral‐valve regurgitation showed LAA fibrosis for patients with SR + MR or AF was significantly increased compared to patients with SR. This implies LAA fibrosis may contribute as an arrhythmia substrate for AF but also in those with SR and coincidence of MR. AF, atrial fibrillation; CABG, coronary artery bypass graft; LAA, left atrial appendage; MR, mitral valve regurgitation; SR, sinus rhythm

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  Figure 5. Kaplan–Meier curve of CABG subgroups: SR, SR + MR, AF, AF + MR. Regardless of SR, AF, or MR, our propensity matched CABG patients exhibited no significant differences in mortality. Anticoagulation therapy for AF patients and LAA resection as thromboembolic prophylaxis must be considered, presumably contributing to the similar survival distributions between CABG subgroups. AF, atrial fibrillation; CABG, coronary artery bypass graft; LAA, left atrial appendage; MR, mitral valve regurgitation; SR, sinus rhythm