Atrial fibrillation and coronary microvascular dysfunction - A Clinical Signal
H Abu Katash, L Zornitzki, O Freund, I Loewenstein, J Ben Shoshan, S Banai, M KonigsteinAbstract
Background
Coronary microvascular dysfunction (CMD) is increasingly recognized as a cause of myocardial ischemia in the absence of obstructive coronary artery disease. Emerging evidence suggests a pathophysiologic link between CMD and atrial fibrillation (AF), potentially mediated by endothelial dysfunction, atrial ischemia, and systemic inflammation. However, data based on invasive assessment of coronary microvascular function remain limited.
Methods
We conducted a single-center retrospective analysis of prospectively collected data from consecutive patients undergoing clinically indicated invasive coronary microvascular assessment between November 2019 and January 2025. All patients underwent coronary angiography with physiological assessment of the left anterior descending artery, including fractional flow reserve, coronary flow reserve (CFR), index of microvascular resistance (IMR), and resistive reserve ratio (RRR). CMD was defined as the presence of at least one abnormal parameter (CFR <2.5, IMR >25, or RRR <3.5). Associations between AF and CMD were evaluated using univariate and multivariable logistic regression analyses.
Results
Among 422 patients included (median age 69 years; 55% female), CMD was identified in 219 (52%). AF was more prevalent in patients with CMD compared with those without CMD (13% vs. 6%, p=0.019). In multivariable analysis, AF was independently associated with CMD (adjusted odds ratio [aOR] 2.09, 95% CI 1.09–4.33, p=0.029), along with older age and ischemic heart disease. Among patients with CMD, those with AF were older and demonstrated higher left ventricular filling pressures and reduced right ventricular systolic function. A trend toward higher prevalence of persistent or permanent AF was observed in CMD patients with AF compared with those without CMD.
Conclusions
Atrial fibrillation is independently associated with coronary microvascular dysfunction in patients with nonobstructive coronary artery disease. These findings support a mechanistic link between CMD and atrial arrhythmogenesis and suggest that patients with CMD may benefit from enhanced rhythm surveillance. Further prospective studies are warranted to clarify causality and clinical implications.Flowchart summarizing the study populationFor image description, please refer to the figure legend and surrounding text.