Cavotricuspid isthmus dependent flutter is associated with an increased incidence of occult coronary artery disease

Atrial flutter (AFl) and atrial fibrillation (AFib) share many clinical risk factors and potential mechanisms with atherosclerosis. Despite this, an association between stable coronary artery disease (CAD) and atrial arrhythmias has not previously been documented. To investigate this hypothesis we measured the incidence of occult coronary atheroma on coronary angiography inpatients undergoing radiofrequency ablation procedures. Consecutive coronary angiograms performed on patients with no history or symptoms of CAD undergoing elective ablation of arrhythmias were analysed. Patients were divided into three groups according to their arrhythmia: Typical right AFl, AFib, and a matched control group undergoing ablation for either atrioventricular node-dependent supraventricular tachycardia (SVT) or idiopathic right ventricular outflow tract tachycardia (RVOT). Atherosclerosis on angiography was graded according to the most severe stenosis. A total of 138 patients were included. Groups were evenly matched for age (P = 0.4), risk factors for coronary disease including hypertension (P = 0.38) and diabetes (P = 0.2). The incidence of asymptomatic, occult coronary atheroma was significantly greater in patients with AFl (AFl 54%, AFib 26%, SVT/RVOT 21%, P = 0.005). In contrast there was no higher incidence of occult atheroma in patients with AFib than those with SVT/RVOT (P = 0.68). The majority of atherosclerosis observed was mild, non-obstructive plaque disease (AFl 75%, AFib 44%, SVT/RVOT 67%). There was a significantly greater incidence of occult coronary atheroma in asymptomatic patients undergoing ablation for AFl, suggesting that the mechanism underlying the development of atherosclerosis may also be important in creating the substrate that allows typical right AFl to develop.