CARDIOVASCULAR JOURNAL OF AFRICA • Volume 33, No 3, May/June 2022 AFRICA 113 upon completion of PVI, and 11 underwent direct-current synchronised cardioversion (DCC) after PVI because the left ventricular ejection fraction (LVEF) was ≤ 35% (n = 6), or based on the operator’s discretion. Two patients were lost to follow up after the initial CA. The remaining 138 patients who still had AF after PVI were included in this study (Fig. 1). All patients received 1 mg ibutilide infusion for AF termination. The patients were assigned to two groups according to their response to the infusion: those with successful AF termination (ibutilide responders, n = 86) and those without AF termination (ibutilide non-responders, n = 52). This study was approved by the institutional review board and ethics committee of Peking Union Medical College Hospital (approval number: S-K998). Persistent AF was defined as AF lasting more than seven days. Long-standing persistent AF was defined as AF lasting more than one year. AF duration was defined as the duration from the date of AF detection on 12-lead electrocardiogram or 24-hour Holter monitor, to the date of initial CA. All patients underwent transoesophageal echocardiography to exclude any left atrial thrombi before CA. The target-activated clotting time was 300–350 seconds. Circumferential PVI was performed in all patients. The PVI endpoint was bidirectional electrical conduction block between the left atrium and the PV. After PVI, 1 mg of ibutilide (dissolved in 20 ml of 0.9% sodium chloride) was administered by slow intravenous injection over 10 minutes. The injection was discontinued on conversion to SR, occurrence of ventricular tachycardia, or any adverse reaction. All patients were observed for 20 minutes after ibutilide administration. Patients with AF termination after the ibutilide infusion were defined as responders; those with persistent AF, as non-responders. If AF was converted to atrial flutter (AFL) or atrial tachycardia (AT), the AFL or AT was mapped and ablated. If AF persisted, a second ibutilide infusion (1 mg) or DCC was administered until termination of AF. No ventricular tachycardia, torsade de pointes, or significant hypotensive response was observed during or after the ibutilide infusion. Additional linear ablation was performed at the operator’s discretion. The endpoint of linear ablation was bidirectional electrical conduction block across the lines. Superior vena cava (SVC) isolation was performed when rapid SVC activity was observed. Ablation was performed using a catheter with an open, irrigated tip (Thermocool SmartTouch; Biosense-Webster Inc, Diamond Bar, CA, USA). Electro-anatomical mapping systems (CARTO XP or CARTO 3; Biosense-Webster Inc, Diamond Bar, CA, USA) were used to guide the procedures. AADs were prescribed during the first three months after the initial ablation; thereafter, AAD use was at the physician’s discretion. Anticoagulation therapy was employed for a minimum of three months after the ablation. After three months, anticoagulants were administered at the clinician’s discretion. Patients were assessed every three months to determine AA recurrence by 24-hour Holter monitoring at the out-patient clinic. Patients were followed up for at least 12 months after ablation. In patients with symptoms suggestive of recurrence of arrhythmia, 12-lead electrocardiogram and 24-hour Holter monitor recordings were additionally performed. The primary endpoint was any documented AA recurrence (AF, AFL or AT). AA recurrence was defined as the presence of AA lasting longer than 30 seconds after the blanking period of 90 days. Statistical analysis Continuous data are expressed as mean ± standard deviation for normally distributed data or as median (interquartile range, IQR) for non-normally distributed data. Categorical data are presented as absolute values and percentages. Tests for significance were conducted using the t-test or non-parametric test (Mann−Whiney U-test) for continuous variables, or χ2 test or Fisher’s exact test for categorical variables. Multivariate logistic regression analysis was used to analyse the clinical covariates associated with failed AF termination after ibutilide administration. Univariate and multivariate Cox proportional hazards models were employed to determine the clinical covariates associated with recurrent AA, and the results are presented as hazard ratio (HR) with 95% confidence interval (CI). Comparisons of the Kaplan−Meier curves between ibutilide responders and non-responders were assessed with a two-sided Mantel−Haenszel (log-rank) test. A p-value < 0.05 was considered statistically significant. All statistical analyses were performed using the statistical software SPSS (v.21.0; IBM Corporation, Armonk, NY, USA). Results The baseline characteristics of the included patients are summarised in Table 1. The average age of the non-paroxysmal 193 patients with non-paroxysmal atrial fibrillation 169 patients 140 patients receiving 1 mg ibutilide infusion after PVI 24 patients excluded: • with valvular heart disease: n = 3 • with cardiac surgery history: n = 4 • with hyperthyroidism history: n = 13 • failed intraprocedural cardioversion: n = 4 29 patients excluded: • sinus rhythm before catheter ablation: n = 7 • conversion to sinus rhythm during or upon PVI completion: n = 11 • direct current cardioversion directly after PVI: n = 11 • Ibutilide responders: n = 87 • lost to follow up: n = 1 86 patients included in the primary analysis • Ibutilide non-responders: n = 53 • lost to follow up: n = 1 52 patients included in the primary analysis Fig. 1. Patient flow diagram. Ibutilide responders were defined as those with successful AF termination after the first infusion of ibutilide (1 mg). Ibutilide non-responders were defined as those with failed AF termination. PVI, pulmonary vein isolation.
RkJQdWJsaXNoZXIy NDIzNzc=