- Email: [email protected]
P4-91
S248 Methods: 16 pts (12 M, 56⫾11 years, LVEF 25⫾10%) candidates for CRT were studied. A pressure-volume (PV) catheter (CD-Leycom) and a steerable pacing catheter were positioned in the LV using a combination of retroaortic and transseptal approaches. 11 predetermined LV pacing sites were assessed in random order: basal and mid-cavity - septal, anterior, lateral, inferior; apex, coronary sinus (CS), and the endocardial site facing the CS pacing site. For each site, ⫹LV dP/dtmax during baseline (AAI) and DDD LV pacing at a fixed rate (sinus rate ⫹ 10 bpm) were compared using a short (84⫾19 ms) and a long (134⫾23 ms) AV delay, both ensuring constant LV capture. Results: Baseline ⫹dP/dt max showed no significant variations. In all but one patient, at least one tested site showed increased ⫹dP/dtmax during DDD LV pacing. However, significant inter-individual variation existed, ranging from -26 to ⫹77%; significant variation was also observed from site to site in a given patient (ANOVA, p⬍0.05). In addition, ⫹ dP/dtmax increased more with a long vs. short AV delay (24⫾20% vs. 19⫾19%, p⫽ns). Pacing from the CS provided significantly less improvement when compared to the corresponding endocardial site (17⫾18% vs. 27⫾17%, p⬍0.05). At the best endocardial site in each patient, dP/dtmax increased from 662⫾306 to 900⫾315mmHg/sec (42⫾22%, p⬍0.05), significantly more than at the CS (17⫾18%, p⬍0.05) in 14 patients, whereas the CS pacing site was optimal in 2 patients. Conclusion: Improvement of LV systolic function varies widely according to the pacing site. Accordingly, optimization of CRT may require individual hemodynamic evaluation. Pacing from the coronary sinus is rarely associated with the maximal improvement and is significantly less effective than pacing at the corresponding endocardial site. P4-89 FEASIBILITY OF PERMANENT HIS BUNDLE PACING USING A NON FLUOROSCOPIC APPROACH Domenico Catanzariti, MD, Massimiliano Maines, MD, Chiara Salgarello, PhD, Tiziana Marotta, MD and Giuseppe Vergara, MD. S. Maria del Carmine Hospital, Rovereto, Italy and Medtronic, Milan, Italy. Permanent His bundle pacing (HP) can avoid pacing-induced dyssynchrony. Fluoroscopy exposure (FE) during HP may be relevant. Non fluoroscopic (NF) systems could allow to renavigate different leads within a 3D reconstructed cardiac map in the atrioventricular junction (AVJ) to the proximal His bundle (HB). Aim: To assess feasibility and safety of HP using a NF navigational system (LocaLisa) in comparison with fluoroscopy-guided (F) approach. Methods: 20 pts with narrow QRS (and HV⬍60 msec), undergoing permanent HP for “brady-tachy” syndrome (10) or permanent atrial fibrillation with atrioventricular block (AVB, 6; 1 AVJ ablation) and supraHisian complete AVB (4) were randomised to F vs. NF implant. A 4.1 F screw-in lead (Select Secure, Medtronic, Inc.), inserted within a deflectable sheath, was fixed in the HB position above (16) or across (4) the tricuspid valve, guided by endocardial pacemapping and HB unipolar potentials recordings. Total procedural (TP) and FE times, screw-in lead fixation attempts (FA) and para-Hisian pacing (PHP; indirect capture of HB) were assessed. Results: HP was effective and safe in all pts. TP and FE times and number of FA in the NF gr. vs. F gr. of pts were 130⫾17 min. vs. 149⫾23 min. (p⫽0.11), 23.25 ⫾ 8.24 (14-38) min. vs. 8.41 ⫾ 8.25 (5-13)min.(p⬍0.05) and 1.75 ⫾ 0.7 vs. 3.5 ⫾ 0.92 respectively (p⬍0.05). In 1 of 10 F pts and 3 of 10 NF pts, PHP was obtained (p⫽0.26). HB pacing threshold (⫻ 0.5 msec) and impedance at implant and at the last follow-up visit were 1.20V⫾0.53 and 1.26⫾0.78 V, 574⫾ 82 and 539⫾ 112 ohms respectively, without differences in the F and NF gr.. Ventricular sensing was statistically different only between the HP and PHP pts gr.: 9.25⫾1.5 mV and 3.3⫾1.1 mV respectively (p⫽0.001). In a mean follow-up of 169⫾162 days (range 41-491), 2 of 16 HP pts (1 in F and 1 in NF gr.) had ventricular undersensing (due to low voltage HB intrinsic deflection) and/or paroxysmal atrial fibrillation oversensing, solved inserting a right ventricular apex (RVA) lead (inserted in other 6 pts as a back-up). Conclusion: HP is feasible and safe with relatively low FE. A NF
Heart Rhythm, Vol 3, No 5, May Supplement 2006 navigation system can assist in reducing screw-in lead FA and FE in comparison with a radiological approach. P4-90 EFFECTS OF CCM (CARDIAC CONTRACTILITY MODULATION) SIGNAL DELIVERY ON LEFT VENTRICULAR CONTRACTILITY Thomas Lawo, MD, Leif I. Bo¨sche, MD, Thomas Deneke, MD, Matthias Vogt, MS and Andreas Mu¨gge, MD, PhD. University Hospital Bochum, Bochum, Germany and Impulse Dynamics Inc., Zug, Switzerland. Introduction: Non-excitatory cardiac stimulation during the refractory period is a novel modality for treating chronic heart failure. Stimuli with an amplitude of up to 7.5 V and a duration of up to 24 ms are delivered during the absolute refractory period. Experimental studies show that CCM stimulation (CCMS) leads to elevated intracellular Ca⫹⫹ levels and is associated with increased contractility (C) as determined by the velocity of ventricular pressure rise (dp/dt). The FIX-CHF-3 study has proven the safety and acute effectiveness of this therapy. Long-term hemodynamic effects of CCMS are investigated in the European FIX-CHF-4 study. Methods: After giving their informed consent to be enrolled in the study, patients underwent implantation of the unit. The effect of CCMS on contractility was determined from left ventricular dp/dt data measured with a Millar catheter. Three standard pacemaker leads were positioned in the right atrium and ventricle through the subclavian vein. CCMS was initiated with an external signal generator. If the dp/dt increased by more than 5% beyond baseline, a permanent impulse generator (Optimizer II/III - Impulse Dynamics) was implanted. Results: In 26 of 28 patients (P) among 156 P in Europe, stimulation was hemodynamically effective and these patients underwent implantation of a permanent impulse generator without complications. dp/dt increased from a mean value of 1010⫾290mmHg/sec to a mean value of 1088⫾310mmHg/sec. The average percent increase was 7.8⫾3.7%. In one patient, C increased from 910mmHg/sec to 1117mmHg/sec, a 22.8% increase above baseline. The graph depicts the C changes in a single patient. Summary: In most patients, CCMS leads to a significant C increase. The long-term effects of this treatment can only be assessed after completion of the study. P4-91 VALIDATION OF A NEW CARDIAC RESYNCHRONIZATION THERAPY OPTIMIZATION ALGORITHM BASED ON PEAK ENDOCARDIAL ACCELERATION: FIRST CLINICAL RESULTS Peter P. Delnoy, MD, Henk Oudeluttikhuis, MD, D. Nicastia, MD, Emanuela Marcelli, PhD, Fabrizio Renesto, PhD and Gianni Plicchi, PhD. Isala Klinieken, Heart Lung Centre,
Poster 4 Zwolle, The Netherlands, Bologna University, Bologna, Italy and Sorin Group CRM, Saluggia, Italy. Background: The optimization of cardiac resynchronization therapy (CRT) devices is time consuming not only at implant time but also during follow-up, when remodeling occurs, requiring re-programming. During AV delay (AVD) scanning, Peak Endocardial Acceleration (PEA), assessed using a microaccelerometer inserted in the tip of a right ventricle (RV) lead, depends both on contractility (Left Ventricle (LV) dP/dtmax) and on A-wave transmitral flow, that is directly related to degree of mitral leaflets opening, giving indication of global LV function. A new CRT optimization algorithm is based on the assessment of the PEA values during AVD scanning for each pacing configuration (PEAarea is estimated as the mean value of PEA values): a wider PEAarea corresponds to a greater improvement of cardiac function. Aim of this study is the validation of the new PEAarea method to optimize CRT, comparing it with the results obtained using LVdP/dtmax. Methods: a biventricular pacemaker (Living CHF, Sorin) connected to a PEA sensor RV lead was implanted in 10 patients (70 ⫾ 5 years) with impaired LV function (NYHA class III or IV, QRS 168ms ⫾ 19). At each pacing configuration (LV, BiV0, LR12, LR40, RL12, RL40), AVD scanning ranging from 60 to 220 ms was automatically performed. A pressure catheter (Millar) inserted in the LV was used to measure LVdP/dtmax at each pacing configuration. Hemodynamic responders to CRT were defined by % change in LVdP/dtmax ⱖ10%. For each patient the Student-NewmanKeuls test (at ␣⫽0.05) was performed on LVdP/dtmax values to determine optimal CRT configurations. Results: 7/10 pts were classified as responders to CRT. In 6/7 responders the optimal pacing configuration suggested by the PEAarea index corresponded to the greatest hemodynamic improvement, as indicated by LVdP/ dtmax. Conclusions: The consistent results of PEAarea with indications given by a contractility index (LVdP/dtmax) are the basis to introduce this new operator-independent and cost-effective method for optimization of CRT devices. P4-92 OPTIMAL HAEMODYNAMIC AV DELAY DURING EXERCISE CAN BE PREDICTED BY PERFORMING OPTIMISATION AT REST WITH ELEVATED PACING RATE Zachary I. Whinnett, MRCP, Justin E. Davies, MRCP, Catherine A. Briscoe, RN, Keith Willson, PhD, Manisty H. Charlotte, MRCP, D. Wyn Davies, MD, FRCP, Alun D. Hughes, MD, PhD, Jamil Mayet, MD, FRCP and Darrel P. Francis, MD, MBBS. Imperial College and St Mary’s Hospital, London, United Kingdom, St. Mary’s Hospital, London, United Kingdom, Royal Brompton Hospital, London, United Kingdom and St. Mary’s Hospital London, London, United Kingdom. Background: Ideally optimisation of atrioventricular (AV) delay of cardiac resynchronisation therapy would be performed during exercise, as this is when patients are most symptomatic. However, this can be technically difficult and inconvenient for the patient. It may be possible to use fast pacing at rest to simulate exercise, however, account has be taken for the difference in optimal AV delay between atrial pacing and sensing. We test a pacing model for exercise, to determine whether it is possible at rest to predict the haemodynamic peak AV delay determined during exercise. Methods and Results: We performed AV delay optimisation, using non-invasive haemodynamics by Finometer, in 12 biventricular pacemaker patients, using our system for maximising signal-to-noise ratio. We calculated the difference between the haemodynamic optimal AV delay for atrial paced and atrial sensed AV delay at resting rates (the “sensed-paced optimum difference”). We subtracted this from the optimal AV delay found with atrial pacing at 100bpm, in order to create a “predicted exercise AV optimum”. Patients separately underwent haemodynamic optimisation during actual treadmill exercise (⬃100bpm), to test the validity of the resting prediction. All patients showed a clear optimum. The actual exercise
S249 optimal AV delay was shorter than the 100 bpm pacing value and was closely predicted by our resting formula (r⫽0.87, p⬍0.001). The rootmean-square difference between predicted and actual was only 14ms. Conclusions: Actual exercise haemodynamic optimisation is possible, in patients able to exercise for several minutes. The exercise optimum for AV delay can be determined from resting optimisation, if the sensed-paced difference is also measured. This may allow appropriate exercise AV delays to be selected without the need for optimisation during exercise. P4-93 CARDIOVASCULAR SAFETY PROFILE OF ELECTRICAL STUN GUNS (TASER®): IMPACT OF POINT OF DELIVERY ON VENTRICULAR FIBRILLATION THRESHOLDS Dhanunjaya R. Lakkireddy, MD, William Kowalewski, BA, Donald W. Wallick, PhD, Atul Verma, MD, David O. Martin, MD, MPH, Kay Ryschon, MS, Jagdish Butany, MBBS, Andrea Natale, MD and Patrick J. Tchou, MD. Cleveland Clinic Foundation, Cleveland, OH and Toronto General Hospital, Toronto, Ontario, Canada. Context: Stun guns gained popularity with law enforcement authorities in subduing violent subjects and have raised serious safety concerns. However, the cardiovascular safety profile of these devices and the effect of point of delivery have not been well established. Methods: We tested 13 adult pigs using a custom device built to deliver multiples of standard stun gun discharge that matched the waveform of a commercially available device (TASER® X-26, TASER International, Scottsdale, AZ). Stun gun discharges were applied in a step-up and stepdown fashion, using two tethered darts at five locations: Sternal notch to cardiac apex (position-1), sternal notch to supra-umbilical (position-2), sternal notch to infra-umbilical (position-3), side to side on chest (position-4) and upper to lower mid posterior torso (position-5). End points included determination of maximum safety multiple (MSM), minimum VF inducing multiple (MVFIM) and VF threshold (VFT) Results: Standard stun gun discharges (x1) did not cause VF at any of the 5 locations. The MSM, MVFIM and VFT of the stun gun were much lower when applied in the axis of the heart (position-1) (4.31⫾1.11 vs. 40.77⫾9.54, 8.31⫾2.69 vs. 50.77⫾9.54 and 6.31⫾1.9 vs. 46.54⫾8.99 respectively) than when applied away from the heart on the dorsum (position-5). The values of the end points at position-1, position-3 and position-4 were progressively higher and ranged in between position-1 and position-5. There was no evidence of myocardial damage based on serum cardiac markers, electrocardiography and echocardiography. No significant metabolic and hemodynamic changes were seen after standard stun gun discharge. Conclusions: Standard stun gun discharge doesn’t cause VF at any paired dart locations. Applications away from the cardiac axis and cardiac apex have higher VF safety margin than those close to it.
Heart Rhythm, Vol 3, No 5, May Supplement 2006 navigation system can assist in reducing screw-in lead FA and FE in comparison with a radiological approach. P4-90 EFFECTS OF CCM (CARDIAC CONTRACTILITY MODULATION) SIGNAL DELIVERY ON LEFT VENTRICULAR CONTRACTILITY Thomas Lawo, MD, Leif I. Bo¨sche, MD, Thomas Deneke, MD, Matthias Vogt, MS and Andreas Mu¨gge, MD, PhD. University Hospital Bochum, Bochum, Germany and Impulse Dynamics Inc., Zug, Switzerland. Introduction: Non-excitatory cardiac stimulation during the refractory period is a novel modality for treating chronic heart failure. Stimuli with an amplitude of up to 7.5 V and a duration of up to 24 ms are delivered during the absolute refractory period. Experimental studies show that CCM stimulation (CCMS) leads to elevated intracellular Ca⫹⫹ levels and is associated with increased contractility (C) as determined by the velocity of ventricular pressure rise (dp/dt). The FIX-CHF-3 study has proven the safety and acute effectiveness of this therapy. Long-term hemodynamic effects of CCMS are investigated in the European FIX-CHF-4 study. Methods: After giving their informed consent to be enrolled in the study, patients underwent implantation of the unit. The effect of CCMS on contractility was determined from left ventricular dp/dt data measured with a Millar catheter. Three standard pacemaker leads were positioned in the right atrium and ventricle through the subclavian vein. CCMS was initiated with an external signal generator. If the dp/dt increased by more than 5% beyond baseline, a permanent impulse generator (Optimizer II/III - Impulse Dynamics) was implanted. Results: In 26 of 28 patients (P) among 156 P in Europe, stimulation was hemodynamically effective and these patients underwent implantation of a permanent impulse generator without complications. dp/dt increased from a mean value of 1010⫾290mmHg/sec to a mean value of 1088⫾310mmHg/sec. The average percent increase was 7.8⫾3.7%. In one patient, C increased from 910mmHg/sec to 1117mmHg/sec, a 22.8% increase above baseline. The graph depicts the C changes in a single patient. Summary: In most patients, CCMS leads to a significant C increase. The long-term effects of this treatment can only be assessed after completion of the study. P4-91 VALIDATION OF A NEW CARDIAC RESYNCHRONIZATION THERAPY OPTIMIZATION ALGORITHM BASED ON PEAK ENDOCARDIAL ACCELERATION: FIRST CLINICAL RESULTS Peter P. Delnoy, MD, Henk Oudeluttikhuis, MD, D. Nicastia, MD, Emanuela Marcelli, PhD, Fabrizio Renesto, PhD and Gianni Plicchi, PhD. Isala Klinieken, Heart Lung Centre,
Poster 4 Zwolle, The Netherlands, Bologna University, Bologna, Italy and Sorin Group CRM, Saluggia, Italy. Background: The optimization of cardiac resynchronization therapy (CRT) devices is time consuming not only at implant time but also during follow-up, when remodeling occurs, requiring re-programming. During AV delay (AVD) scanning, Peak Endocardial Acceleration (PEA), assessed using a microaccelerometer inserted in the tip of a right ventricle (RV) lead, depends both on contractility (Left Ventricle (LV) dP/dtmax) and on A-wave transmitral flow, that is directly related to degree of mitral leaflets opening, giving indication of global LV function. A new CRT optimization algorithm is based on the assessment of the PEA values during AVD scanning for each pacing configuration (PEAarea is estimated as the mean value of PEA values): a wider PEAarea corresponds to a greater improvement of cardiac function. Aim of this study is the validation of the new PEAarea method to optimize CRT, comparing it with the results obtained using LVdP/dtmax. Methods: a biventricular pacemaker (Living CHF, Sorin) connected to a PEA sensor RV lead was implanted in 10 patients (70 ⫾ 5 years) with impaired LV function (NYHA class III or IV, QRS 168ms ⫾ 19). At each pacing configuration (LV, BiV0, LR12, LR40, RL12, RL40), AVD scanning ranging from 60 to 220 ms was automatically performed. A pressure catheter (Millar) inserted in the LV was used to measure LVdP/dtmax at each pacing configuration. Hemodynamic responders to CRT were defined by % change in LVdP/dtmax ⱖ10%. For each patient the Student-NewmanKeuls test (at ␣⫽0.05) was performed on LVdP/dtmax values to determine optimal CRT configurations. Results: 7/10 pts were classified as responders to CRT. In 6/7 responders the optimal pacing configuration suggested by the PEAarea index corresponded to the greatest hemodynamic improvement, as indicated by LVdP/ dtmax. Conclusions: The consistent results of PEAarea with indications given by a contractility index (LVdP/dtmax) are the basis to introduce this new operator-independent and cost-effective method for optimization of CRT devices. P4-92 OPTIMAL HAEMODYNAMIC AV DELAY DURING EXERCISE CAN BE PREDICTED BY PERFORMING OPTIMISATION AT REST WITH ELEVATED PACING RATE Zachary I. Whinnett, MRCP, Justin E. Davies, MRCP, Catherine A. Briscoe, RN, Keith Willson, PhD, Manisty H. Charlotte, MRCP, D. Wyn Davies, MD, FRCP, Alun D. Hughes, MD, PhD, Jamil Mayet, MD, FRCP and Darrel P. Francis, MD, MBBS. Imperial College and St Mary’s Hospital, London, United Kingdom, St. Mary’s Hospital, London, United Kingdom, Royal Brompton Hospital, London, United Kingdom and St. Mary’s Hospital London, London, United Kingdom. Background: Ideally optimisation of atrioventricular (AV) delay of cardiac resynchronisation therapy would be performed during exercise, as this is when patients are most symptomatic. However, this can be technically difficult and inconvenient for the patient. It may be possible to use fast pacing at rest to simulate exercise, however, account has be taken for the difference in optimal AV delay between atrial pacing and sensing. We test a pacing model for exercise, to determine whether it is possible at rest to predict the haemodynamic peak AV delay determined during exercise. Methods and Results: We performed AV delay optimisation, using non-invasive haemodynamics by Finometer, in 12 biventricular pacemaker patients, using our system for maximising signal-to-noise ratio. We calculated the difference between the haemodynamic optimal AV delay for atrial paced and atrial sensed AV delay at resting rates (the “sensed-paced optimum difference”). We subtracted this from the optimal AV delay found with atrial pacing at 100bpm, in order to create a “predicted exercise AV optimum”. Patients separately underwent haemodynamic optimisation during actual treadmill exercise (⬃100bpm), to test the validity of the resting prediction. All patients showed a clear optimum. The actual exercise
S249 optimal AV delay was shorter than the 100 bpm pacing value and was closely predicted by our resting formula (r⫽0.87, p⬍0.001). The rootmean-square difference between predicted and actual was only 14ms. Conclusions: Actual exercise haemodynamic optimisation is possible, in patients able to exercise for several minutes. The exercise optimum for AV delay can be determined from resting optimisation, if the sensed-paced difference is also measured. This may allow appropriate exercise AV delays to be selected without the need for optimisation during exercise. P4-93 CARDIOVASCULAR SAFETY PROFILE OF ELECTRICAL STUN GUNS (TASER®): IMPACT OF POINT OF DELIVERY ON VENTRICULAR FIBRILLATION THRESHOLDS Dhanunjaya R. Lakkireddy, MD, William Kowalewski, BA, Donald W. Wallick, PhD, Atul Verma, MD, David O. Martin, MD, MPH, Kay Ryschon, MS, Jagdish Butany, MBBS, Andrea Natale, MD and Patrick J. Tchou, MD. Cleveland Clinic Foundation, Cleveland, OH and Toronto General Hospital, Toronto, Ontario, Canada. Context: Stun guns gained popularity with law enforcement authorities in subduing violent subjects and have raised serious safety concerns. However, the cardiovascular safety profile of these devices and the effect of point of delivery have not been well established. Methods: We tested 13 adult pigs using a custom device built to deliver multiples of standard stun gun discharge that matched the waveform of a commercially available device (TASER® X-26, TASER International, Scottsdale, AZ). Stun gun discharges were applied in a step-up and stepdown fashion, using two tethered darts at five locations: Sternal notch to cardiac apex (position-1), sternal notch to supra-umbilical (position-2), sternal notch to infra-umbilical (position-3), side to side on chest (position-4) and upper to lower mid posterior torso (position-5). End points included determination of maximum safety multiple (MSM), minimum VF inducing multiple (MVFIM) and VF threshold (VFT) Results: Standard stun gun discharges (x1) did not cause VF at any of the 5 locations. The MSM, MVFIM and VFT of the stun gun were much lower when applied in the axis of the heart (position-1) (4.31⫾1.11 vs. 40.77⫾9.54, 8.31⫾2.69 vs. 50.77⫾9.54 and 6.31⫾1.9 vs. 46.54⫾8.99 respectively) than when applied away from the heart on the dorsum (position-5). The values of the end points at position-1, position-3 and position-4 were progressively higher and ranged in between position-1 and position-5. There was no evidence of myocardial damage based on serum cardiac markers, electrocardiography and echocardiography. No significant metabolic and hemodynamic changes were seen after standard stun gun discharge. Conclusions: Standard stun gun discharge doesn’t cause VF at any paired dart locations. Applications away from the cardiac axis and cardiac apex have higher VF safety margin than those close to it.