Predictors and prognostic significance of tachycardiomyopathy: insights from a cohort of 1269 patients undergoing atrial flutter ablation

Background Atrial flutter‐related tachycardiomyopathy ( AFL‐TCM ) is a rare and treatable cause of heart failure. Little is known about its epidemiology and long‐term prognosis. Our aims are to determine the prevalence, predictors and outcomes of AFL‐TCM . Methods and results A total of 1269 patients were referred for radiofrequency ablation of AFL between January 1996 and September 2014; 184 had reduced left ventricular ejection fraction ( LVEF <40%). At 6 months after AFL ablation, 103 patients (8.1% of the population, 56% of patients with baseline LVEF <40%) had marked LVEF improvement: these were considered to have AFL‐TCM . Patients with persisting reduced LVEF were considered to have systolic dysfunction unrelated to AFL . Patients were followed for a median (percentile 25–75 ) of 1.15 (0.4–2.8) years. Patients with AFL‐TCM were younger, had lower prevalence of ischaemic cardiomyopathy and used less antiarrhythmic drugs than patients with systolic dysfunction unrelated to AFL . In multivariable analysis, ischemic cardiomyopathy [odds ratio ( OR ) = 0.32, 95% confidence interval ( CI ) 0.15–0.68) P  = 0.003] and prescription of antiarrhythmic drug before ablation [ OR  = 0.41, 95% CI 0.20–0.84, P  = 0.02] were significantly associated with a lower probability of LVEF improvement during follow‐up. Patients with AFL‐TCM had similar survival to patients without systolic dysfunction at baseline [hazard ratio ( HR ) = 0.96 95% CI 0.34–2.65, P  = 0.929], whereas patients with systolic dysfunction unrelated to AFL had higher mortality rates compared with patients without systolic dysfunction at baseline [ HR  = 2.88, 95% CI 1.45–5.72, P  = 0.002]. Conclusions Marked LVEF improvement was observed in 56% of patients with baseline LVEF <40% at 6 months after ablation. These patients had similar survival to patients without baseline systolic dysfunction, whereas patients who remained with LVEF <40% had a threefold increase in mortality rates.