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Published on: February 26, 2013
Class 1C antiarrhythmic drugs in atrial fibrillation and coronary artery disease
Peter G Pantlin1, Robert M Bober1,2, Michael L Bernard1
1Department of Cardiology, Ochsner Clinical School, University of Queensland, New Orleans, Louisiana.
Insights
Class 1C antiarrhythmic drugs (AADs) appear safe for atrial fibrillation (AF) patients with occult coronary artery disease (CAD) and preserved heart function. This pilot study found no increased mortality risk in patients treated with 1C AADs compared to controls.
Area of Science:
- Cardiology
- Pharmacology
- Medical Imaging
Background:
- Class 1C antiarrhythmic drugs (AADs) are common atrial fibrillation (AF) treatments but often avoided in patients with coronary artery disease (CAD).
- The safety of 1C AADs in patients with CAD but without evident ischemia or myocardial infarction remains unclear.
- Reduced coronary flow capacity (CFC), assessed by positron emission tomography (PET), identifies flow-limiting CAD.
Purpose of the Study:
- To determine if 1C AAD treatment increases mortality in AF patients with reduced CFC, indicating occult CAD, but without known CAD.
- To evaluate the safety of 1C AADs in a specific subgroup of AF patients with preserved cardiac function.
Main Methods:
- A pilot study compared 78 AF patients treated with 1C AADs to 78 age-matched controls without 1C AADs.
- All participants had preserved left ventricular ejection fraction (≥50%) and underwent PET-based quantification of myocardial blood flow and CFC.
- Patients with clinically evident CAD or prior myocardial infarction were excluded; mortality was tracked via follow-up and death index searches.
Main Results:
- Over a mean follow-up of 2.0 years, survival rates were similar between the 1C AAD-treated group and the control group (P=.54).
- Among patients with reduced CFC indicating occult CAD (affecting ≥50% of myocardium), 1C AAD treatment did not significantly alter survival compared to non-treated patients (P=.44).
Conclusions:
- In a select group of AF patients with preserved left ventricular function and PET-identified occult CAD, 1C AADs did not appear to increase mortality.
- Larger studies are necessary to definitively establish the safety of 1C AADs in this patient population.
Background:
Class 1C antiarrhythmic drugs (AADs) are effective first-line agents for atrial fibrillation (AF) treatment. However, these agents commonly are avoided in patients with known coronary artery disease (CAD), due to known increased risk in the postmyocardial infarction population. Whether 1C AADs are safe in patients with CAD but without clinical ischemia or infarct is unknown. 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 left ventricular ejection fraction ≥50% who were treated with 1C AADs to age-matched AF patients without 1C AAD treatment. No patient had clinically evident CAD (ie, reversible perfusion defect, known ≥70% epicardial lesion, percutaneous coronary intervention, coronary artery bypass grafting, or myocardial infarction). All patients had PET-based quantification of stress myocardial blood flow and CFC. Death was assessed by clinical follow-up and social security death index search.
Results:
A total of 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 = .54). Among patients with CFC indicating the presence of occult CAD (ie, reduced CFC involving ≥50% of myocardium), 1C-treated patients had survival similar to (P = .44) those not treated with 1C agents.
Conclusions:
In a limited population of AF patients with preserved left ventricle 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 the safety of these drugs in this context.
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