Key result
AF is linked to ~37% lower global hyperemic myocardial blood flow versus sinus rhythm.
Why the study?
Previous studies linked AF to reduced hyperemic myocardial blood flow, but it remained unknown whether an independent association exists between AF and myocardial blood flow in symptomatic patients with suspected obstructive CAD.
Is ongoing atrial fibrillation independently associated with impaired hyperemic myocardial blood flow on [15O]H2O PET imaging in symptomatic patients with suspected obstructive coronary artery disease after matching for coronary atherosclerosis severity?
Cross-Sectional (n=151)
No
Is ongoing atrial fibrillation independently associated with impaired hyperemic myocardial blood flow on [15O]H2O PET imaging in symptomatic patients with suspected obstructive coronary artery disease after matching for coronary atherosclerosis severity?
Because atrial fibrillation independently reduces hyperemic myocardial blood flow even after accounting for epicardial coronary stenosis severity on CCTA and results in lower revascularization rates on invasive angiography (33% vs 63%), standard PET MBF cutoff values (<2.3 mL/g/min) may overestimate obstructive CAD in patients with AF.
A characteristic feature of obstructive coronary artery disease (CAD) is impaired myocardial blood flow (MBF). Previous studies have shown that atrial fibrillation (AF) is also associated with reduced hyperemic MBF. However, it is unknown whether an independent association exists between AF and MBF in symptomatic patients with suspected obstructive CAD. We studied 874 patients at Kuopio University Hospital (Finland) who underwent coronary computed tomography angiography (CCTA) and [ 15 O]H 2 O myocardial perfusion positron emission tomography due to suspected obstructive CAD in 2017–2023. The final cohort comprised 31 AF patients and 120 propensity score-matched sinus rhythm (SR) patients. The matching criteria were age, sex, body mass index, number of traditional risk factors for CAD (0–5), calcium score, and total CCTA status (i.e., the overall severity of CCTA findings). Global hyperemic MBF was lower in AF patients than in SR patients (median 1.9 mL/g/min [IQR 1.4–2.6 mL/g/min] vs. 3.0 mL/g/min [IQR 2.4–3.6 mL/g/min], p < 0.001). Impaired hyperemic MBF (< 2.3 mL/g/min in ≥ 1 segment) was more frequent in AF patients (n = 25/31, 81%) than in SR patients (n = 50/120, 42%, p < 0.001). Furthermore, the presence of AF was independently associated with reduced hyperemic MBF in three multivariate general linear models (p < 0.001 in each model). To summarize, AF was independently associated with impaired hyperemic MBF in patients with suspected obstructive CAD. This association should be considered in clinical practice when interpreting the results of myocardial perfusion imaging in patients with AF.
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Vartiainen et al. (2026) conducted a cross-sectional in Suspected obstructive coronary artery disease with or without ongoing atrial fibrillation (n=151). Ongoing atrial fibrillation during [15O]H2O PET myocardial perfusion imaging vs. Ongoing sinus rhythm during [15O]H2O PET myocardial perfusion imaging (propensity score-matched 1:4 on age, sex, BMI, CAD risk factors, calcium score, and total CCTA status) was evaluated on Global hyperemic myocardial blood flow (MBF, mL/g/min) quantified by [15O]H2O PET during adenosine stress (p=<0.001). Atrial fibrillation was independently associated with lower global hyperemic myocardial blood flow compared to matched sinus rhythm controls (median 1.9 vs. 3.0 mL/g/min, p<0.001).
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