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Background: The presence of focal fibrillation waves during atrial fibrillation (AF) can, besides ectopic activity, also be explained by asynchronous activation of the atrial endo- and epicardial layer and transmurally propagating fibrillation waves. To provide direct proof of endo-epicardial asynchrony, we performed simultaneous high-resolution mapping of the right atrial endo- and epicardial wall during AF in humans.Method and Results: Intraoperative mapping of the endo- and epicardial right atrial wall was performed during (induced) AF in 10 patients with AF (paroxysmal: n=3; persistent: n=4; and longstanding persistent: n=3) and 4 patients without a history of AF. A clamp made of 2 rectangular 8×16 electrode arrays (interelectrode distance 2 mm) was inserted into the incision in the right atrial appendage. Recordings of 10 seconds of AF were analyzed to determine the incidence of asynchronous endo-epicardial activation times (≥15 ms) of opposite electrodes. Asynchronous endo-epicardial activation ranged between 0.9 and 55.9% without preference for either side. Focal waves appeared equally frequent at endocardium and epicardium (11% versus 13%; ITALIC! P=0.18). Using strict criteria for breakthrough (presence of an opposite wave within 4 mm and ≤14 ms before the origin of the focal wave), the majority (65%) of all focal fibrillation waves could be attributed to endo-epicardial excitation.Conclusions: We provided the first evidence for asynchronous activation of the endo-epicardial wall during AF in humans. Endo-epicardial asynchrony may play a major role in the pathophysiology of AF and may offer an explanation why in some patients therapy fails. [ABSTRACT FROM AUTHOR]

Aims: The significance and incidences of intraoperative arrhythmias occurring in the operating room (OR) in children with congenital heart disease (CHD) are unknown. Aims of this study were to determine incidences of intraoperative arrhythmias in children with CHD and to examine whether they are associated with persistent arrhythmias during follow-up.Methods and results: Continuous ECG recordings obtained from 134 consecutive paediatric CHD patients were manually examined from the moment the aortic cross-clamp (ACC) was removed [use of ACC and cardiopulmonary bypass (CPB)], when CPB was stopped (use of only CPB) or when the sternum was closed (no use of ACC and CPB) until departure from the OR. In the OR, 2nd (60%) and 3rd (34%) degree atrioventricular conduction block (AVB), ectopic atrial rhythm (30%), and junctional rhythm (32%) were most often observed in patients who underwent surgery with both ACC and CPB. Incidences of these arrhythmias decreased after cessation of CPB (P < 0.01). (Supra)ventricular premature beats were mostly observed between end of ACC time and sternum closure (64-84%), but decreased before departure from the OR (6-16%, P < 0.01). During a median follow-up of 37 months, 17 patients (13%) had new onset, late post-operative arrhythmias. Of these patients, 88% had intraoperative arrhythmias compared with 85% of patients without late post-operative arrhythmias (P = 1).Conclusion: Intraoperative arrhythmias, mainly 2nd degree AVB and (supra)ventricular premature beats, were frequently observed in children with CHD undergoing cardiac surgery with use of CPB and ACC. Most arrhythmias were short-lasting and transient and appeared not to be related to late post-operative arrhythmias. [ABSTRACT FROM AUTHOR]

Objective: Outcomes after surgical repair of complete atrioventricular septal defect (cAVSD) have improved. With advancing age, the risk of development of dysrhythmias may increase. The aims of this study were to (1) examine development of sinus node dysfunction (SND), atrial and ventricular tachyarrhythmias, and (2) study progression of atrioventricular conduction abnormalities in young adult patients with repaired cAVSD., Study Design: In this retrospective multicenter study, 74 patients (68% female) with a cAVSD repaired in childhood were included. Patients' medical files were evaluated for occurrence of SND, atrioventricular conduction block (AVB), atrial and ventricular tachyarrhythmias., Results: Median age at repair was 6 months (interquartile range 3-10) and median age at last follow-up was 24 years (interquartile range 21-28). SND occurred after a median of 17 years (interquartile range 11-19) after repair in 23% of patients, requiring pacemaker implantation in two patients (12%). Regular supraventricular tachycardia was observed in three patients (4%). Atrial fibrillation and ventricular tachyarrhythmias were not observed. Twenty-seven patients (36%) had first-degree AVB, which was self-limiting in 16 (59%) and persistent in 10 (37%) patients. One patient developed third-degree AVB 7 days after left atrioventricular valve replacement. Spontaneous type II second-degree AVB occurred in a 28-year-old patient. Both patients underwent pacemaker implantation., Conclusions: Clinically significant dysrhythmias were uncommon in young adult patients after cAVSD repair. However, three patients required pacemaker implantation for either progression of SND or spontaneous type II second-degree AVB. Longer follow-up should point out whether dysrhythmias will progress or become more prevalent with increasing age., (© 2018 The Authors. Congenital Heart Disease Published by Wiley Periodicals, Inc.)

Aims: The significance and incidences of intraoperative arrhythmias occurring in the operating room (OR) in children with congenital heart disease (CHD) are unknown. Aims of this study were to determine incidences of intraoperative arrhythmias in children with CHD and to examine whether they are associated with persistent arrhythmias during follow-up., Methods and Results: Continuous ECG recordings obtained from 134 consecutive paediatric CHD patients were manually examined from the moment the aortic cross-clamp (ACC) was removed [use of ACC and cardiopulmonary bypass (CPB)], when CPB was stopped (use of only CPB) or when the sternum was closed (no use of ACC and CPB) until departure from the OR. In the OR, 2nd (60%) and 3rd (34%) degree atrioventricular conduction block (AVB), ectopic atrial rhythm (30%), and junctional rhythm (32%) were most often observed in patients who underwent surgery with both ACC and CPB. Incidences of these arrhythmias decreased after cessation of CPB (P < 0.01). (Supra)ventricular premature beats were mostly observed between end of ACC time and sternum closure (64-84%), but decreased before departure from the OR (6-16%, P < 0.01). During a median follow-up of 37 months, 17 patients (13%) had new onset, late post-operative arrhythmias. Of these patients, 88% had intraoperative arrhythmias compared with 85% of patients without late post-operative arrhythmias (P = 1)., Conclusion: Intraoperative arrhythmias, mainly 2nd degree AVB and (supra)ventricular premature beats, were frequently observed in children with CHD undergoing cardiac surgery with use of CPB and ACC. Most arrhythmias were short-lasting and transient and appeared not to be related to late post-operative arrhythmias.

Aims: Atrial fibrillation (AF) is increasingly observed in patients with congenital heart defects (CHDs) who survive nowadays into adulthood. Yet, predictors of AF are scarce in this high-risk population. This study therefore examined the predictive ability of atrial extrasystole (AES) for development of AF in CHD patients., Methods and Results: Adult CHD patients who had a 24 h Holter registration were followed to determine who developed AF. A total of 573 patients (49% male, mean age 35 ± 12 years) were included; they had a simple/complete repaired CHD (n = 279), complex repaired CHD (n = 251), or univentricular heart (UVH, n = 43). Ageing (P < 0.0001), female gender (P = 0.028), UVH (P = 0.0010), and left atrial dilatation (P = 0.0025) were associated with the number of AES. During a median follow-up of 51.6 months (interquartile range 22.8-85.7), 29 patients (5%) developed de novo AF. An one-point increase in the number of logtotal-AES was associated with a two-fold higher risk of AF development (hazard ratio 1.95; 95% confidence interval 1.21-3.13; P = 0.016). C-statistic for left atrial dilatation, complexity, and age had a good discriminative ability for the incidence of AF with a C-statistic of 84.5%. The addition of the total number of AES/24 h to this model increased C-statistic to 88.4%., Conclusion: Atrial extrasystole occur relatively frequent in adult CHD patients compared with patients with other cardiac diseases. This is the first study that showed an association between an increased AES frequency and a higher risk of AF development in CHD patients., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.)