Vincenzo Russo1, Ignasi Anguera2, Frederik J de Lange3, Ermenegildo De Ruvo4, Jérôme Taieb5, Marco Zardini6, Gerardo Nigro7, Daniele Giacopelli8, Alessio Gargaro9, Michele Brignole10. 1. Department of Cardiology, Chair of Cardiology, University of the Study of Campania "Luigi Vanvitelli", Ospedale Monaldi, Napoli, Italy. Electronic address: vincenzo.russo@unicampania.it. 2. Arrhythmia Unit, Heart Diseases Institute, Bellvitge University Hospital Bellvitge Biomedical Research Institute IDIBELL, Barcelona, Spain. 3. Department of Clincal and Experimental Cardiology, Amsterdam Cardiovascular Sciences, Amsterdam University Medical Centre, University of Amsterdam, Heart Centre, Amsterdam, the Netherlands. 4. Department of Cardiology, Policlinico Casilino, Roma, Italy. 5. Department of Cardiology, Centre Hospitalier du Pays d'Aix, Aix-en-Provence, France. 6. Department of Cardiology, Azienda Ospedaliero - Universitaria di Parma, Parma, Italy. 7. Department of Cardiology, Chair of Cardiology, University of the Study of Campania "Luigi Vanvitelli", Ospedale Monaldi, Napoli, Italy. 8. Research Clinical Unit, Biotronik Italy, Vimodrone (MI), Italy; Department of Cardiac, Thoracic, Vascular Sciences & Public Health, University of Padova, Italy. 9. Research Clinical Unit, Biotronik Italy, Vimodrone (MI), Italy. 10. Department of cardiovascular, Neural and Metabolic Sciences, Faint & Fall Programme, IRCCS Istituto Auxologico Italiano, Ospedale San Luca, Milano, Italy; Department of Cardiology, Arrhythmology Centre and Syncope Unit, Ospedali del Tigullio, Lavagna, Italy.
Abstract
BACKGROUND: Undiagnosed sinus or atrioventricular node dysfunction may bias estimation of the real efficacy of cardiac pacing in preventing vasovagal reflex syncope. We assessed this hypothesis in the BIOSync CLS trial which showed that dual-chamber pacing with closed loop stimulation (CLS) remarkably reduced recurrences of syncope. METHODS AND RESULTS: In the study patients aged 40 years or older with ≥2 episodes of loss of consciousness in the last year and an asystolic response to Tilt-Table test were randomized to pacing ON (DDD-CLS mode) or pacing OFF (ODO mode). We utilized the available pacemaker diagnostic data in a total of 103 patients (52 pacing ON, 51 pacing OFF) to generate cumulative distribution charts for heart rate (HR) and percentage of pacing. At 12 months, we did not find evidence of suspected sinus or atrioventricular node dysfunction. Beats were similarly distributed between groups (p = 0.96), with an average HR of 76 ± 8 bpm (pacing ON) versus 77 ± 7 bpm (pacing OFF). In the active group, the median percentage of atrial and ventricular pacing was 47% and 0%, respectively. Intolerance to high pacing rates was reported in only one patient (1.6%) and was easily resolved by reprogramming the maximum CLS pacing rate. CONCLUSIONS: We did not find evidence of suspected sinus or atrioventricular node dysfunction in the BIOSync CLS patients. The benefit of pacing should be ascribed to pacing prevention of pure vasovagal episodes. CLS algorithm modulated pacing rates over a wide frequency range, consistently competing with sinus node.
BACKGROUND: Undiagnosed sinus or atrioventricular node dysfunction may bias estimation of the real efficacy of cardiac pacing in preventing vasovagal reflex syncope. We assessed this hypothesis in the BIOSync CLS trial which showed that dual-chamber pacing with closed loop stimulation (CLS) remarkably reduced recurrences of syncope. METHODS AND RESULTS: In the study patients aged 40 years or older with ≥2 episodes of loss of consciousness in the last year and an asystolic response to Tilt-Table test were randomized to pacing ON (DDD-CLS mode) or pacing OFF (ODO mode). We utilized the available pacemaker diagnostic data in a total of 103 patients (52 pacing ON, 51 pacing OFF) to generate cumulative distribution charts for heart rate (HR) and percentage of pacing. At 12 months, we did not find evidence of suspected sinus or atrioventricular node dysfunction. Beats were similarly distributed between groups (p = 0.96), with an average HR of 76 ± 8 bpm (pacing ON) versus 77 ± 7 bpm (pacing OFF). In the active group, the median percentage of atrial and ventricular pacing was 47% and 0%, respectively. Intolerance to high pacing rates was reported in only one patient (1.6%) and was easily resolved by reprogramming the maximum CLS pacing rate. CONCLUSIONS: We did not find evidence of suspected sinus or atrioventricular node dysfunction in the BIOSync CLSpatients. The benefit of pacing should be ascribed to pacing prevention of pure vasovagal episodes. CLS algorithm modulated pacing rates over a wide frequency range, consistently competing with sinus node.