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Incidence of atrial fibrillation in pacemaker patients with frequent and rare ventricular stimulation
Session 15 appropriate detection of AA. Of the total AMS EGMs, clinical diagnoses of AA were distributed as follows: AF 39%, atrial flutter (AFL) 18%, AT 13%. When atrial tachycardia detection rates (ATDR) were programmed ⬍200 ppm, significantly more inappropriate diagnoses were made than ATDRⱖ200 ppm (31.3% vs. 24.8%, p⬍0.01). Post ventricular atrial refractory periods (PVARP)⬎275 ms exhibited significantly more inappropriate diagnoses than PVARPⱕ275 ms (37.6% vs. 28.6%, p⬍0.01). Conclusion: PM parameters have a significant effect on the efficacy of AMS to detect the incidence of AA. Proper ATDR programming reduces the incidence of inappropriate AMS by capturing true AA events at rates ⬎200 ppm. Decreasing PVARPⱕ275 ms reduces inappropriate AMS episodes, which may be due to competitive atrial pacing in the setting of retrograde VA conduction.
S29 into the groups A (“V-Pace” ⬍50 %) or B (“V-Pace” ⱖ50 %). Both groups were compared in regard to: Number of AF episodes/day, mean episode duration (hours/episode), number of premature atrial contractions (PAC’s)/ hour, total AF burden (% of follow-up). Results: See Table (all figures are presented as median values). Conclusions: 1. Patients with a high rate of ventricular stimulation during DDD(R) pacing exhibit a significantly higher AF burden than patients with a low ventricular pacing rate. 2. The increased AF burden is mainly due to a longer mean AF episode duration. 3. Unnecessary ventricular stimulation should therefore be avoided in patients with dual chamber pacing.
AB15-3 EFFECT OF PACING THE RIGHT VENTRICULAR MID-SEPTUM TRACT IN PATIENTS WITH PERMANENT ATRIAL FIBRILLATION AND LOW EJECTION FRACTION Cosimo Sacra, Carmine Muto, Giovanni Carreras, Michelangelo Canciello, Luigi Ascione, L. Ottaviano, Maria Accadia, S. Rumolo, Pio F. Tartaglia, Luigi Irace, Fabio Minicucci, Salvatore Angelini and Bernardino Tuccillo. Ospedale Loreto Mare, Napoli, Italy. Objectives: Aim of this study was to evaluate the effect of different sites of right ventricular (RV) pacing in patients with permanent Atrial Fibrillation (pAF) and low ejection fraction (EF) needing a PM implantation. Methods and Results: From June 2000 to January 2003, 173 pts (91male, mean age 72 years) with cAF and EF ⬍30% as measured by Echocardiography (Echo), underwent VVI pacemakers implantation. All patients were on medical therapy. Reguarding the site of RV pacing, patients were divided in two groups: Group A including 83 pts with the electrocatheter (ec) tip placed in the RV mid septum, and group B of 90 pts with the ec tip placed at the apex of RV. The right position of ec tip in the mid septum was assessed by fluoroscopy and Echo. The site of pacing in group A was considered appropriate when paced QRS axis on ECG resulted the most similar to the spontaneous QRS. All patients had clinical and Echo control after 1,3 and 6 months after PM implantation, to assess NYHA class and EF. After six months the NYHA class changed from 2.9⫾0.4 to 1.8 ⫾ 0.4 (p⫽0.01) in group A, and from 3.0 ⫾ 0.5 to 2.6 ⫾ 0.7 in group B (p⫽ns). EF increased at least of 5% in group A, while no significant changes were observed in group B. Conclusion: Present study suggest that more physiological pacing from the mid septum RV, can improve EF and quality of life in pts whith cAF and low EF, needing a PM implantation. AB15-4 INCIDENCE OF ATRIAL FIBRILLATION IN PACEMAKER PATIENTS WITH FREQUENT AND RARE VENTRICULAR STIMULATION Alexander Yang, MD, Alexander Bitzen, MD, Lars M. Lickfett, MD, Markus Linhart, MD, Christian Schneider, MD, Bahman Esmailzadeh, MD, Fritz Mellert, MD, Armin Welz, MD, Berndt Lu¨deritz, MD, Thorsten Lewalter, MD on behalf of the VIP Study Group. University of Bonn, Bonn, Germany. Nielsen et al. (2003) and the MOST study have demonstrated that right ventricular stimulation during dual chamber pacing increases the risk of atrial fibrillation (AF) in patients with sinus node dysfunction. In these investigations AF was diagnosed by 12-lead ECG’s at the follow-up visits. The objective of the current study was to present a detailed AF characterisation according to advanced pacemaker (PM) diagnostic features in patients with a high and low rate of ventricular stimulation. Methods: The PM diagnostic data of 249 patients with dual chamber pacing (“Selection series”, Vitatron Medical BV, Dieren, NL) and a history of paroxysmal AF were analysed after a follow-up of 99,9 ⫾ 42,3 days. According to the rate of ventricular stimulation the patients were divided
AB15-5 A NOVEL RECTANGULAR BIPHASIC WAVEFORM FROM A RADIOFREQUENCY DEFIBRILLATOR COMPARED WITH A CONVENTIONAL WAVEFORM FOR THE TRANSVENOUS CARDIOVERSION OF CHRONIC ATRIAL FIBRILLATION IN PATIENTS Benedict M. Glover, MRCP, Conor J. Mc Cann, MRCP, Simon J. Walsh, MRCP, Michael J. Moore, MRCP, Ganesh Manoharan, MD, Michael J. Roberts, MD, Carol M. Wilson, MRCP, John D. Allen, MD, Jennifer Adgey, MD and *John Anderson. Royal Victoria Hospital, Belfast, United Kingdom and University of Ulster, Jordanstown, United Kingdom. Purpose: The optimal waveform for the transvenous direct current cardioversion (DCC) of atrial fibrillation (AF) is unknown. A novel rectangular biphasic waveform (6/6msec duration, phase 2 peak voltage 50% of phase 1) delivered from a radiofrequency (RF) powered defibrillator was compared with a conventional capacitor based exponential biphasic waveform of equivalent duration and voltage. Method: Patients with chronic AF (fully anticoagulated) were randomised to receive either the RF or a conventional trapezoidal waveform (Ventritex HVS-02). Defibrillation electrodes were positioned in the right atrial appendage (cathode) and distal coronary sinus (anode). All shocks were R-wave synchronised. Phase 1 peak voltage was increased in stepwise progression from 50V-300V. Success was defined as return of sinus rhythm for ⱖ 30 seconds. Cardiac troponin and CKMB were checked post procedure. Results: Patients (n⫽16, 11 male) received 83 shocks (RF⫽40, conventional⫽43). Mean age was 63 (⫾11.6) years, mean BMI was 28 (⫾6) and mean duration of AF was 5.8 (⫾5.7) months. The groups were matched in terms of age, gender, BMI, duration of AF, aetiology, drugs and echocardiographic features. The RF waveform performed significantly better than the conventional waveform for the cardioversion of chronic AF (7 of 8 patients (87%) versus 1 of 8 patients (12%) success, p ⫽ 0.003). The mean leading edge voltage for the RF was 221V (Range 100-300) and for the conventional waveform was 240V. No significant arrhythmias, sinus pauses or episodes of hypotension occurred. There was no elevation of cardiac enzymes. Conclusions: The novel biphasic waveform has a superior efficacy at a lower voltage compared with the conventional waveform in the transvenous cardioversion of AF. There were no arrhythmic, haemodynamic complications or elevation of markers of myocardial injury. Use of this waveform may improve the efficacy of implantable devices for the treatment of AF. AB15-6 RADIOGRAPHIC LOCALIZATION OF BACHMANNS BUNDLE HOW CLOSE ARE WE? *David O’Donnell, MBBS, Luke Birchill, MBBS, Voltaire Nadurata, MD and Wes Mohammed, MBBS. Austin Hospital, Melbourne, Australia.
S29 into the groups A (“V-Pace” ⬍50 %) or B (“V-Pace” ⱖ50 %). Both groups were compared in regard to: Number of AF episodes/day, mean episode duration (hours/episode), number of premature atrial contractions (PAC’s)/ hour, total AF burden (% of follow-up). Results: See Table (all figures are presented as median values). Conclusions: 1. Patients with a high rate of ventricular stimulation during DDD(R) pacing exhibit a significantly higher AF burden than patients with a low ventricular pacing rate. 2. The increased AF burden is mainly due to a longer mean AF episode duration. 3. Unnecessary ventricular stimulation should therefore be avoided in patients with dual chamber pacing.
AB15-3 EFFECT OF PACING THE RIGHT VENTRICULAR MID-SEPTUM TRACT IN PATIENTS WITH PERMANENT ATRIAL FIBRILLATION AND LOW EJECTION FRACTION Cosimo Sacra, Carmine Muto, Giovanni Carreras, Michelangelo Canciello, Luigi Ascione, L. Ottaviano, Maria Accadia, S. Rumolo, Pio F. Tartaglia, Luigi Irace, Fabio Minicucci, Salvatore Angelini and Bernardino Tuccillo. Ospedale Loreto Mare, Napoli, Italy. Objectives: Aim of this study was to evaluate the effect of different sites of right ventricular (RV) pacing in patients with permanent Atrial Fibrillation (pAF) and low ejection fraction (EF) needing a PM implantation. Methods and Results: From June 2000 to January 2003, 173 pts (91male, mean age 72 years) with cAF and EF ⬍30% as measured by Echocardiography (Echo), underwent VVI pacemakers implantation. All patients were on medical therapy. Reguarding the site of RV pacing, patients were divided in two groups: Group A including 83 pts with the electrocatheter (ec) tip placed in the RV mid septum, and group B of 90 pts with the ec tip placed at the apex of RV. The right position of ec tip in the mid septum was assessed by fluoroscopy and Echo. The site of pacing in group A was considered appropriate when paced QRS axis on ECG resulted the most similar to the spontaneous QRS. All patients had clinical and Echo control after 1,3 and 6 months after PM implantation, to assess NYHA class and EF. After six months the NYHA class changed from 2.9⫾0.4 to 1.8 ⫾ 0.4 (p⫽0.01) in group A, and from 3.0 ⫾ 0.5 to 2.6 ⫾ 0.7 in group B (p⫽ns). EF increased at least of 5% in group A, while no significant changes were observed in group B. Conclusion: Present study suggest that more physiological pacing from the mid septum RV, can improve EF and quality of life in pts whith cAF and low EF, needing a PM implantation. AB15-4 INCIDENCE OF ATRIAL FIBRILLATION IN PACEMAKER PATIENTS WITH FREQUENT AND RARE VENTRICULAR STIMULATION Alexander Yang, MD, Alexander Bitzen, MD, Lars M. Lickfett, MD, Markus Linhart, MD, Christian Schneider, MD, Bahman Esmailzadeh, MD, Fritz Mellert, MD, Armin Welz, MD, Berndt Lu¨deritz, MD, Thorsten Lewalter, MD on behalf of the VIP Study Group. University of Bonn, Bonn, Germany. Nielsen et al. (2003) and the MOST study have demonstrated that right ventricular stimulation during dual chamber pacing increases the risk of atrial fibrillation (AF) in patients with sinus node dysfunction. In these investigations AF was diagnosed by 12-lead ECG’s at the follow-up visits. The objective of the current study was to present a detailed AF characterisation according to advanced pacemaker (PM) diagnostic features in patients with a high and low rate of ventricular stimulation. Methods: The PM diagnostic data of 249 patients with dual chamber pacing (“Selection series”, Vitatron Medical BV, Dieren, NL) and a history of paroxysmal AF were analysed after a follow-up of 99,9 ⫾ 42,3 days. According to the rate of ventricular stimulation the patients were divided
AB15-5 A NOVEL RECTANGULAR BIPHASIC WAVEFORM FROM A RADIOFREQUENCY DEFIBRILLATOR COMPARED WITH A CONVENTIONAL WAVEFORM FOR THE TRANSVENOUS CARDIOVERSION OF CHRONIC ATRIAL FIBRILLATION IN PATIENTS Benedict M. Glover, MRCP, Conor J. Mc Cann, MRCP, Simon J. Walsh, MRCP, Michael J. Moore, MRCP, Ganesh Manoharan, MD, Michael J. Roberts, MD, Carol M. Wilson, MRCP, John D. Allen, MD, Jennifer Adgey, MD and *John Anderson. Royal Victoria Hospital, Belfast, United Kingdom and University of Ulster, Jordanstown, United Kingdom. Purpose: The optimal waveform for the transvenous direct current cardioversion (DCC) of atrial fibrillation (AF) is unknown. A novel rectangular biphasic waveform (6/6msec duration, phase 2 peak voltage 50% of phase 1) delivered from a radiofrequency (RF) powered defibrillator was compared with a conventional capacitor based exponential biphasic waveform of equivalent duration and voltage. Method: Patients with chronic AF (fully anticoagulated) were randomised to receive either the RF or a conventional trapezoidal waveform (Ventritex HVS-02). Defibrillation electrodes were positioned in the right atrial appendage (cathode) and distal coronary sinus (anode). All shocks were R-wave synchronised. Phase 1 peak voltage was increased in stepwise progression from 50V-300V. Success was defined as return of sinus rhythm for ⱖ 30 seconds. Cardiac troponin and CKMB were checked post procedure. Results: Patients (n⫽16, 11 male) received 83 shocks (RF⫽40, conventional⫽43). Mean age was 63 (⫾11.6) years, mean BMI was 28 (⫾6) and mean duration of AF was 5.8 (⫾5.7) months. The groups were matched in terms of age, gender, BMI, duration of AF, aetiology, drugs and echocardiographic features. The RF waveform performed significantly better than the conventional waveform for the cardioversion of chronic AF (7 of 8 patients (87%) versus 1 of 8 patients (12%) success, p ⫽ 0.003). The mean leading edge voltage for the RF was 221V (Range 100-300) and for the conventional waveform was 240V. No significant arrhythmias, sinus pauses or episodes of hypotension occurred. There was no elevation of cardiac enzymes. Conclusions: The novel biphasic waveform has a superior efficacy at a lower voltage compared with the conventional waveform in the transvenous cardioversion of AF. There were no arrhythmic, haemodynamic complications or elevation of markers of myocardial injury. Use of this waveform may improve the efficacy of implantable devices for the treatment of AF. AB15-6 RADIOGRAPHIC LOCALIZATION OF BACHMANNS BUNDLE HOW CLOSE ARE WE? *David O’Donnell, MBBS, Luke Birchill, MBBS, Voltaire Nadurata, MD and Wes Mohammed, MBBS. Austin Hospital, Melbourne, Australia.