Pacemaker use for the treatment of reflex-mediated syncope: 40-year experience at a single paediatric institution

Introduction: Reflex-mediated syncope occurs in 15% of children and young adults. In rare instances, pacemakers are required to treat syncopal episodes associated with transient sinus pauses or atrioventricular block. This study describes a single centre experience in the use of permanent pacemakers to treat syncope in children and young adults. Materials and methods: Patients with significant pre-syncope or syncope and pacemaker implantation from 1978 to 2018 were reviewed. Data collected included the age of presentation, method of diagnosis, underlying rhythm disturbance, age at implant, type of pacemaker implanted, procedural complications and subsequent symptoms. Results: Fifty patients were identified. Median age at time of the first syncopal episode was 10.2 (range 0.3–20.4) years, with a median implant age of 14.9 (0.9–34.3) years. Significant sinus bradycardia/pauses were the predominant reason for pacemaker implant (54%), followed by high-grade atrioventricular block (30%). Four (8%) patients had both sinus pauses and atrioventricular block documented. The majority of patients had dual-chamber pacemakers implanted (58%), followed by ventricular pacemakers (38%). Median follow-up was 6.7 (0.4–33.0) years. Post-implant, 4 (8%) patients continued to have syncope, 7 (14%) had complete resolution of their symptoms, and the remaining reported a decrease in their pre-syncopal episodes and no further syncope. Twelve (24%) patients had complications, including two infections and eight lead malfunctions. Conclusions: Paediatric patients with reflex-mediated syncope can be treated with pacing. Complication rates are high (24%); as such, permanent pacemakers should be reserved only for those in whom asystole from sinus pauses or atrioventricular block has been well documented.

P6556Prevention of long-lasting atrial fibrillation through device therapy in dual-chamber pacemakers: analysis on 1384 patients of the role of Reactive ATP and atrial preventive pacing

Background Atrial fibrillation (AF) is the most prevalent heart rhythm disorder in clinical practice and it is associated with poor quality of life and increased risks of heart failure, dementia, stroke, and death. Moreover AF management is a huge cost for healthcare systems. AF is irregular, typically originates from the pulmonary veins, and as such, requires cardioversion to terminate persistent episodes. AF is not susceptible to pace-termination, however, the MINERVA trial has shown that AF may transform in slower organized rhythms such as atrial flutter or atrial tachycardia, which can often be terminated by atrial anticahycardia pacing (ATP); in particular by Reactive ATP, a specific ATP feature which can be re-armed when atrial arrhythmias get slower or more regular. The MINERVA trial showed that the combination of ATP, preventive atrial pacing algorithms and minimal ventricular pacing (MVP) was associated with lower progression to persistent and permanent AF, compared with standard DDD pacing mode and to MVP mode, in pacemaker patients with clinical history of AF. Purpose We aimed to confirm MINERVA trial results in real-world clinical practice and to evaluate whether AF prevention was associated with preventive atrial pacing or solely with ATP. Indeed in our project atrial preventive pacing algorithms were not enabled and the pacing mode (DDD or MVP) was chosen according to patients' AV conduction characteristics. Methods Consecutive dual-chamber pacemaker patients with sinus node disease and device detected AT/AF were prospectively followed by 30 Italian cardiologic centers in an observational research. Clinical and device data were collected and reviewed by expert cardiologists to assess AT/AF occurrence through in clinic visit and/or remote transmissions of device data. Results A total of 239 patients (73 years old, 56% male) wearing a dual-chamber pacemaker with Reactive ATP were included in the project, followed for a median observation period of 13 months and compared with 1145 patients included in the MINERVA trial followed for a median observation period of 34 months and programmed with DDD pacing mode (383 patients), MVP (389 patients) and MVP+Reactive ATP+preventive algorithms (373 patients). As shown in the following figure incidence of 7 consecutive days of AF in the patients treated by DDD/MVP+Reactive ATP in real-world clinical practice was very similar to that found in the MINERVA trial arm programmed with MVP+Reactive ATP+preventive algorithms. Incidence of AF longer than 7 days Conclusions Our analysis performed in a population of sinus node disease patients with dual-chamber pacemakers confirmed MINERVA trial results in terms of prevention of long-lasting AF episodes. In particular these results confirm the benefit associated with the use of Reactive ATP, rather than preventive atrial pacing algorithms.

P6545Pacing as new predictor for atrial high rate episodes in patients with dual-chamber pacemakers and no history of atrial fibrillation

Introduction Both atrial and ventricular pacing (AP/VP) have been related to a higher risk of clinical atrial fibrillation (AF) documented on ECG. Subclinical AF is detected as atrial high rate episodes (AHRE) by cardiac implantable electronic devices and is related to a higher risk of stroke. Purpose The aim of this study was to determine whether the percentage of AP and/or VP in patients with pacemakers and no history of AF is related with the future development of subclinical AF (AHRE) and/or clinical AF (ECG documented). Methods From February 2012 to September 2015 we recruited patients with dual chamber pacemakers and no prior history of AF. Patients were followed at 3 months and every year then after. Subclinical AF, clinical AF and cardiovascular events were registered. AHRE (subclinical AF) was defined as an episode of atrial rate ≥225 bpm with a minimum duration of 5 min. Clinical AF was defined as ECG documented AF. Percentage of AP/VP was determined as the mean AP/VP during the first three visits. Mortality and cardiovascular events (including AF, stroke and hospitalization for heart failure) were also recorded. Results 249 patients (57% men; 75±9 years-old) were included. Mean time from pacemaker implantation was 9 months and the main indication was AV-block in 53% of the patients. Mean CHA2DS2-VASc score was 3.5±1.5. After a mean follow-up of 33±11 months, 38.5% of patients developed subclinical AF and 10.4% clinical AF. Patients with AP≥50% presented significantly higher risk of AHRE (62.5% vs 32.3%, OR 3.48; 95% CI [1.93–6.4] p<0.01) and clinical AF (18.7% vs 8.6%, OR 2.4; 95% CI [1.05–5.52] p<0.05). Patients with VP≥50% presented significantly higher risk of AHRE (46.4% vs 31.6%, OR 1.87; 95% CI [1.10–3.24] p<0.05) and clinical AF (25.9% vs 9.7%, OR 2.7; 95% CI [1.13–7.72] p<0.05). The percentage of AP and VP were not related to a higher risk of cardiovascular events or mortality. Multivariate analysis showed that AP≥50% was an independent predictor for AHRE (OR 2.4; 95% CI [1.19–4.97] p=0.014). Conclusions Pacing is related to a higher risk for developing subclinical and clinical AF in patients with dual-chamber pacemakers and no history of previous AF. Our data suggest, that patients presenting a high percentage of AP and VP should be closely followed during routinely pacemaker check-ups assessing for subclinical AF, especially in those with AP ≥50%.