Haemodynamic and hyperaemic effects of adenosine in patients with atrial fibrillation undergoing quantitative myocardial perfusion cardiovascular magnetic resonance.

Aims: Patients with atrial fibrillation (AF) are thought to have an attenuated response to adenosine during vasodilator stress testing. We sought to investigate the haemodynamic and hyperaemic effects of adenosine in patients with AF undergoing adenosine-stress cardiovascular magnetic resonance (CMR) assessment.

Methods and results: We retrospectively examined 318 patients referred for clinical adenosine-stress CMR (AF n = 158, sinus rhythm [SR] n = 160). Baseline and peak heart rate (HR) and quantitative myocardial perfusion were compared between groups. At peak stress, the haemodynamic response was blunted in patients with AF (HR increase 7 ± 10bpm vs. 17 ± 11bpm in SR, P < 0.001). Fewer patients in AF met the threshold for a satisfactory HR response ≥10bpm (40% in AF vs. 76% in SR, P < 0.001). There were no intergroup differences in hyperaemic myocardial blood flow (1.52 ± 0.65 mL/min/g in AF vs. 1.55 ± 0.65 mL/min/g in SR, P = 0.670) or myocardial perfusion reserve (2.66 ± 1.11 in AF vs. 2.66 ± 1.08 in SR, P = 0.981). AF (odds ratio [OR], 0.29 [0.17-0.50], P < 0.001) and left ventricular ejection fraction (OR 1.03 [1.00-1.05], P = 0.023) were independently associated with achieving a satisfactory HR response on multivariable analysis, but only ejection fraction (OR 1.05 [1.02-1.09], P = 0.003) predicted a satisfactory hyperaemic response.

Conclusion: The heart rate response during adenosine-stress CMR is blunted in AF patients. Despite this, the majority of patients with AF generate a sufficient hyperaemic response with a standard adenosine-stress protocol. Further work is needed to determine the diagnostic accuracy of adenosine-stress CMR in patients with AF.