Class 1C antiarrhythmic drugs in atrial fibrillation and coronary artery disease

Abstract

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.

Flecainide in Ventricular Arrhythmias: From Old Myths to New Perspectives

“…Indeed, there are no scientific data demonstrating an increased proarrhythmic risk of flecainide among patients with CAD in the absence of underlying scar and myocardial ischaemia. Conversely, the study by Pantlin et al showed the safety of IC AADs in a population of AF patients with occult CAD on coronary flow capacity at positron emission tomography without history of clinically significant CAD [71]. Moreover, Ashraf et colleagues demonstrated in a retrospective study that there was a similar 10-year survival between patients treated with flecainide with no or minimal CAD, nonobstructive CAD and obstructive CAD.…”

In reply: Impaired myocardial blood flow in atrial fibrillation

“…We thank Cay et al 1 for their interest in our work 2 and we agree that it is important to consider changes in myocardial blood flow (MBF) that may change over time and that may be related to the patient's prevalent heart rhythm.…”

Path4Drug: Data Science Workflow for Identification of Tissue-Specific Biological Pathways Modulated by Toxic Drugs

“…There are two exceptions, one of them is encainide, which is an antiarrhythmic drug of the Ic class. Ic class antiarrhythmic agents are potent Sodium channel blockers ( Pantlin et al, 2020 ). Encainide was withdrawn from the market due to fatal proarrhythmic side effects ( Echt et al, 1991 ).…”