Background: Class 1C antiarrhythmic drugs (AAD) are effective first -line agents for atrial
fibrillation (AF) treatment. However, th ese agents commonly are avoided in patients with
known coronary artery disease (CAD), due to known increased risk in the post-myocardial
infarction population. Whether 1C AADs are safe in patients with CAD but without clinical
ischemia or infarct is unknow n. Reduced coronary flow capacity (CFC) on positron emission
tomography (PET) reliably identifies myocardial regions supplied by vessels with CAD causing
flow limitation.
Objective: To assess whether treatment with 1C AADs increases mortality in patients without
known CAD but with CFC indicating significantly reduced coronary blood flow.
Methods: In this pilot study, we compared patients with AF and LVEF ≥50% who were treated
with 1C AADs, to age-matched AF patients without 1C AAD treatment. No patient had clinically
evident CAD (i.e., reversible perfusion defect, known ≥70% epicardial lesion, PCI, CABG, or
myocardial infarction). All patients had PET- based quantification of stress myocardial blood
flow (sMBF) and CFC. Death was assessed by clinical follow -up and SSDI search.
Results: 78 patients with 1C AAD exposure were matched to 78 controls. Over a mean follow-up
of 2.0 years, the groups had similar survival (p=0.54). Among patients with CFC indicating the
presence of occult CAD (i.e., reduced CFC involving ≥50% of myocardium), 1C -treated patients
had survival similar to (p=0.44) those not treated with 1C agents.
Conclusions: In a limited population of AF patients with preserved LV function and PET CFC
indicating occult CAD, treatment with 1C AADs appears not to increase mortality. A larger study
would be required to confidently assess safety of these drugs in this context.
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