RESUMO
BACKGROUND: The real incidence of atrial arrhythmia (AA) after patent foramen ovale (PFO) closure and whether this complication can be prevented remain unknown. This study assessed if flecainide is effective to prevent AA during the first 3 months after PFO closure, and if 6 months treatment by flecainide is more effective than 3 months to prevent AA after PFO closure. METHODS: AFLOAT is a prospective, multicentre, randomized, open-label, superiority trial with a blind evaluation of all the endpoints (PROBE design). Patients were randomized in a 1:1:1 ratio after PFO closure to receive flecainide (150 mg once a day in a sustained-release (SR) dose) for 3 months, flecainide (150 mg od SR dose) for 6 months, or no additional treatment (standard-of-care) for 6 months. The primary endpoint was the percentage of patients with at least one episode AA (≥30s) recorded within 3 months after PFO closure on long-term monitoring with an insertable cardiac monitor (ICM). The secondary endpoint was the percentage of patients with at least one episode of AA (≥30s) recorded with ICM during the 3-6 months period after PFO closure. RESULTS: 186 patients were included (mean age 54 years, male 68.8%) and AA (≥30s) occurred in 53 (28.5%) patients during the 6-month follow-up; 86.8% of these AA events occurred in the first month after PFO closure. The primary outcome occurred in 33/123 (26.8%) and 16/63 (25.4%) patients receiving flecainide for at least 3 months or standard of care, respectively [Risk Difference (RD) 1.4%; 95% confidence interval (CI) -12.9% to 13.8%, NS]. The secondary endpoint occurred in 3/60 (5.0%), 4/63 (6.3%), and 5/63 (7.9%) patients receiving flecainide 6 months, 3 months or standard of care, respectively [RD -2.9%; 95% CI -12.7% to 6.9%, and RD -1.6%; 95% CI -11.8% to 8.6%, respectively]. CONCLUSIONS: In the first 6 months following successful PFO closure, AA (≥30s) occurred in 28.5% of cases, mostly in the first month after the procedure. Flecainide did not prevent AA after PFO closure.
RESUMO
AIMS: KCNQ1 mutations cause QTc prolongation increasing life-threatening arrhythmias risks. Heterozygous mutations [type 1 long QT syndrome (LQT1)] are common. Homozygous KCNQ1 mutations cause type 1 Jervell and Lange-Nielsen syndrome (JLNS) with deafness and higher sudden cardiac death risk. KCNQ1 variants causing JLNS or LQT1 might have distinct phenotypic expressions in heterozygous patients. The aim of this study is to evaluate QTc duration and incidence of long QT syndrome-related cardiac events according to genetic presentation. METHODS AND RESULTS: We enrolled LQT1 or JLNS patients with class IV/V KCNQ1 variants from our inherited arrhythmia clinic (September 1993 to January 2023). Medical history, ECG, and follow-up were collected. Additionally, we conducted a thorough literature review for JLNS variants. Survival curves were compared between groups, and multivariate Cox regression models identified genetic and clinical risk factors. Among the 789 KCNQ1 variant carriers, 3 groups were identified: 30 JLNS, 161 heterozygous carriers of JLNS variants (HTZ-JLNS), and 550 LQT1 heterozygous carriers of non-JLNS variants (HTZ-Non-JLNS). At diagnosis, mean age was 3.4 ± 4.7 years for JLNS, 26.7 ± 21 years for HTZ-JLNS, and 26 ± 21 years for HTZ-non-JLNS; 55.3% were female; and the mean QTc was 551 ± 54â ms for JLNS, 441 ± 32â ms for HTZ-JLNS, and 467 ± 36â ms for HTZ-Non-JLNS. Patients with heterozygous JLNS mutations (HTZ-JLNS) represented 22% of heterozygous KCNQ1 variant carriers and had a lower risk of cardiac events than heterozygous non-JLNS variant carriers (HTZ-Non-JLNS) [hazard ratio (HR) = 0.34 (0.22-0.54); P < 0.01]. After multivariate analysis, four genetic parameters were independently associated with events: haploinsufficiency [HR = 0.60 (0.37-0.97); P = 0.04], pore localization [HR = 1.61 (1.14-1.2.26); P < 0.01], C-terminal localization [HR = 0.67 (0.46-0.98); P = 0.04], and group [HR = 0.43 (0.27-0.69); P < 0.01]. CONCLUSION: Heterozygous carriers of JLNS variants have a lower risk of cardiac arrhythmic events than other LQT1 patients.