Aims: Long-term mortality after ablation of typical atrial flutter has been found to be increased two-fold in comparison to atrial fibrillation ablations through a period of 5 years with unclear mechanism.
Methods and results: We analysed 189 consecutive patients who underwent ablation for typical atrial flutter (AFL), in which the incidence of AF was the first manifestation of cardiac disease. According to the clinical standards of our centre, the routine recommendation was to evaluate for coronary artery disease (CAD) by invasive angiogram or computed tomography scan. We compared the AFL patients to 141 patients with paroxysmal atrial fibrillation (AFIB) without known structural heart disease who underwent ablation in the same period and who had routine coronary angiograms performed. Out of 189 patients who presented with AFL, coronary status was available in 152 patients (80.4%). Both groups were balanced for mean age (64.9 years in AFL vs. 63.2 years in AFIB; P = 0.15), body mass index (BMI; 28.8 vs. 28.5 kg/m2; P = 0.15), CHA2DS2-VASc-Score (2.20 vs. 2.04; P = 0.35), smoking status (22.2% smokers vs. 28.4%; P = 0.23), and renal function (GFR >60 mL/min in 96.7% of all patients vs. 95.7%; P = 0.76). There were significantly lower values for left ventricular ejection fraction (52.5% vs. 59.7%; P < 0.001), female sex (17.0% vs. 47.5%; P < 0.001), hyperlipidaemia (37.9% vs. 58.9%; P < 0.001), and family history of cardiovascular disease (CVD) (15.0 vs. 31.9%; P = 0.001) in the AFL vs. AFIB cohorts. Coronary artery disease with stenoses >50% was found in 26.3% of all patients with available coronary status in AFL and in 7.0% in AFIB (P < 0.001). Coronary artery disease with stenoses >75% in 16.4% in AFL whereas only in 1.4% in AFIB (P < 0.001). Multivessel disease was detected in 10.5% in AFL and 0.7% in AFIB (P < 0.001). After correction for age, left ventricular ejection fraction, BMI, CHA2DS2-VASc-Score and its individual components, smoking status, hyperlipidaemia, and family history of CVD, there was a more than five-fold increase in the likelihood of CAD with stenosis >50% in AFL as compared to AFIB [odds ratio (OR 5.26)]. A multivariate analysis was performed in the AFL group. Patients with clinically relevant stenoses (>75%) were older (70.6 years vs. 63.8 years; P = 0.001), had a higher number of risk factors (3.08 vs. 2.24; P ≤ 0.0016) and a higher CHA2DS2-VASc-Score (3.20 vs. 2.00; P < 0.0001). With logistic regression, significant CAD could be predicted by higher values for CHA2DS2-VASc-Score with an exponential rise to a pretest-probability of 42.1% at a value of 4 points.
Conclusion: These data suggest that typical atrial flutter constitutes a manifestation of previously asymptomatic CAD. Due to the inclusion criteria, CAD has to be considered silent and chronic in most of the patients. Therefore, the presence of typical atrial flutter in formerly healthy patients should raise suspicion of otherwise silent CAD and initiate further investigations and risk stratification with particular emphasis on the individual CHA2DS2-VASc-Scores.
Keywords: Atrial fibrillation; Atrial flutter; Coronary artery disease; Risk prediction.