Incidence and Implications of Obstructive Sleep Apnoea in Patients Presenting for Atrial Fibrillation Ablation: A Prospective Study

Background: Incessant focal atrial tachycardia (AT)may be complicated by LV dysfunction. The aim was to characterise the incidence, ECG and EP features of incessant focal AT and identify predictors of tachycardia mediated cardiomyopathy (TCM). Methods: 82 of 345 (24%) pts with focal AT presenting for radiofrequency ablation between 1997 and 2008 were incessant. Incessant AT was defined as continuous tachycardia or recurrent paroxysms of tachycardia separated by ≤2 sinus beats. Results: The mean age was 42± 20 years, 57% were male and mean symptom duration was 5± 7 years. TCM was present in 30/82 (37%), defined as LVEF <50%. Pts with incessant AT and TCM were more likely to be younger (mean 39± 22 year vs. 45± 18 year, p= 0.02); have a slower tachycardia cycle length (TCL) (502± 131ms vs. 446± 106ms, p= 0.05) and slower mean heart rate in tachycardia (117± 21 bpm vs. 132± 33 bpm, p= 0.05) than incessant pts without TCM. Incessant tachycardia was more frequent from atrial appendage (AA, 16/19 (84%)) and pulmonary vein (PV, 26/44 (59%)) sites compared to other anatomic locations (combined, 15%) (p< 0.001). Appendage and PV sites were therefore associated with a higher incidence of TCM (AA: 42%; PV: 18%; other: 6%, p= 0.008). RFA was successfully performed in 76/82 (93%) pts at mean follow up of 22± 26months. In pts with TCM recoveryofLV functionwas seen in 29/30 (97%)pts atmean of 2.8 months. Conclusion: Incessant tachycardia is frequently complicated by TCM. AA and PV foci were more likely to be incessant and complicated by TCM. Incessant tachycardia and TCM was characterized by a slower TCL and mean heart rate than pts without TCMpossibly delaying clinical presentation.