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P5-93
Poster 5
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coupling. In general RV pacing resulted in an earlier RV pressure trace and LV pacing resulted in an earlier LV pressure trace. BiV pacing returned the synchrony towards normal but not completely.
Average implant time for aPSDL was 15 ⫾ 8 min compared to 6 ⫾ 3 min for 6947. R-waves were lower for aPSDL, but there was no difference in the number of undersensed activations during VF. One pt had a significantly higher DFT with the aPSDL (13J vs. 30J) with a 10 decrease in impedance, likely due to current shunting between a low right atrial SVC coil and the RV coil. Average RV diastolic and pulse pressures during sinus rhythm (71⫾ 13 bpm) were 14⫾ 5 mmHg and 34 ⫾13 mmHg, respectively. Diastolic pressure increased to 20 ⫾ 6 mmHg and pulse pressure decreased to 3 ⫾ 1 mmHg after 3 sec of VF (270 ⫾ 69 bpm). P5-94 FUNCTIONAL CAPACITY AND BETA BLOCKER USE CORRELATE WITH SINUS NODE CHRONOTROPIC RESPONSE IN PACEMAKER PATIENTS John F. Macgregor, MD, Lizbeth Mino, PhD, James A. Coman, MD, Kira Q. Stolen, PhD, Timothy E. Meyer, PhD, Stacia Merkel, BS, Donald Hopper, PhD and Roger A. Freedman, MD. University of Utah Medical Center, Salt Lake City, UT, Guidant Corporation, Salt Lake City, UT, Oklahoma Heart Institute, Tulsa, OK and Guidant Corporation, St. Paul, MN.
P5-93 ACUTE CLINICAL FEASIBILITY OF AN INTEGRATED PRESSURE SENSOR DEFIBRILLATION LEAD DESIGN W. Ben Johnson, MD, Mark S. Kremers, MD, J. Russell Bailey, MD, Kevin Hsu, MD, Kevin R. Wheelan, MD, Jay O. Franklin, MD, Mark J. Mayotte, MS, Brian McHenry, MS and Teresa A. Whitman, PhD. Iowa Heart, Des Moines, IA, Mid-Carolina Cardiology, Charlotte, NC, Baylor University Medical Center, Dallas, TX and Medtronic, Inc., Fridley, MN. Background: Right ventricular (RV) pressure measurements may be useful for augmenting the diagnostic functionality of an ICD. We studied the feasibility of incorporating a pressure sensor on a dual-coil defibrillation lead. Lead handling and implant metrics of this apically-implanted pressure sensing defibrillation lead (aPSDL) were compared to a conventional defibrillation lead (Medtronic Model 6947). Methods: The aPSDL is an integrated-bipolar 10 Fr lead with a pressure sensor proximal to the RV coil. The sensor is positioned in the RV outflow tract (RVOT) by fixating the tip in the apex and pushing the RV coil along the trajectory between the apex and RVOT. Ten patients (pts) undergoing ICD implantation temporarily received the aPSDL prior to the Model 6947. Acute pacing and sensing thresholds and RV pressures were recorded. A 3-step binary search defibrillation threshold (DFT) was measured using RV⬎SVC⫹Can. Upon completion of aPSDL testing, the 6947 was implanted in the RV apex and identical data acquired. Results: Table shows electrophysiologic data. Conclusions: 1) aPSDL design had acceptable acute implant performance, but improvements in lead body stiffness and position of SVC coil are warranted. 2) Further study is needed to demonstrate chronic stability of this novel lead shape.
Background: Inadequate heart rate response to exercise, defined as an inability to achieve 85% of age predicted maximal heart rate, has been documented in many pacemaker patients. Changes in functional capacity due to beta-blocker (-b) administration may be attributed to alterations in autonomic function, leading to an impaired chronotropic response (CR). We studied correlates of impaired CR in a large cohort of patients newly implanted with a dual chamber pacemaker in the Limiting Chronotropic Incompetence for Pacemaker Recipients (LIFE) study. Methods: One-month post-implant, patients completed a baseline Chronotropic Assessment Exercise Protocol (CAEP) with rate response turned off. Chronotropic response was assessed by the metabolic-chronotropic relation (MCR) method which relates heart rate reserve and metabolic reserve. 518 patients had adequate 1-month exercise tests, (completed ⱖ 3 stages of exercise; achieved score ⱖ16 on the Rating of Perceived Exertion scale). A subset of 76 patients completed peak cardiopulmonary exercise (CPX) tests for Weber Functional Classification. Results: Univariate analyses showed significant associations between MCR slope and each of the following: New York Heart Association Class (NYHA; p⬍0.0001), Weber Functional Classification (p⬍0.006), and -blocker (-b) use (p⬍0.0001), with lower MCR slopes in those patients with decreased functional capacity and -b use. Within each functional class, patients on -b had lower average slopes compared to patients not on -b. There was a significant difference in MCR slopes between Weber Classes A and C (p⫽0.013). Conclusion: In pacemaker patients, there is an association between a decline in functional status, assessed by both NYHA and Weber classifications, and a reduction in CR. This reduction in CR is magnified by the use of -b within each functional class.
Acute Sensing, Pacing, and Defibrillation Thresholds for aPSDL and Model 6947 (N⫽10)
Lead
R-wave Pacing Amplitude Threshold (mV) (V)
Pacing Defibrillation Shock Impedance Threshold Impedance (ohms) (J) (ohms)
aPSDL 9.5 ⫾ 8.0 0.63 ⫾ 0.28 489 ⫾ 119 15.8 ⫾ 10.4 40 ⫾ 5 Model 15.3 ⫾ 7.0 0.67 ⫾ 0.15 740 ⫾ 174 12.6 ⫾ 8.6 41 ⫾ 5 6947 p-value* ⬍0.05 NS ⬍0.05 NS NS *Comparisons between aPSDL and Model 6947 by paired t-test
P5-95 ATRIAL PACING MAY BE DETRIMENTAL TO ATRIOVENTRICULAR DYSSYNCHRONY Mark S. Wathen, MD, Wade May, MD, C. Andrew Smith, MD, Neil Legaspie, RN and Pablo Saavedra, MD. Vanderbilt University, Nashville, TN. Intro: Recent studies have shown that right ventricular pacing causes dyssynchrony. Similarly, right atrial pacing can cause both interatrial and
S291
coupling. In general RV pacing resulted in an earlier RV pressure trace and LV pacing resulted in an earlier LV pressure trace. BiV pacing returned the synchrony towards normal but not completely.
Average implant time for aPSDL was 15 ⫾ 8 min compared to 6 ⫾ 3 min for 6947. R-waves were lower for aPSDL, but there was no difference in the number of undersensed activations during VF. One pt had a significantly higher DFT with the aPSDL (13J vs. 30J) with a 10 decrease in impedance, likely due to current shunting between a low right atrial SVC coil and the RV coil. Average RV diastolic and pulse pressures during sinus rhythm (71⫾ 13 bpm) were 14⫾ 5 mmHg and 34 ⫾13 mmHg, respectively. Diastolic pressure increased to 20 ⫾ 6 mmHg and pulse pressure decreased to 3 ⫾ 1 mmHg after 3 sec of VF (270 ⫾ 69 bpm). P5-94 FUNCTIONAL CAPACITY AND BETA BLOCKER USE CORRELATE WITH SINUS NODE CHRONOTROPIC RESPONSE IN PACEMAKER PATIENTS John F. Macgregor, MD, Lizbeth Mino, PhD, James A. Coman, MD, Kira Q. Stolen, PhD, Timothy E. Meyer, PhD, Stacia Merkel, BS, Donald Hopper, PhD and Roger A. Freedman, MD. University of Utah Medical Center, Salt Lake City, UT, Guidant Corporation, Salt Lake City, UT, Oklahoma Heart Institute, Tulsa, OK and Guidant Corporation, St. Paul, MN.
P5-93 ACUTE CLINICAL FEASIBILITY OF AN INTEGRATED PRESSURE SENSOR DEFIBRILLATION LEAD DESIGN W. Ben Johnson, MD, Mark S. Kremers, MD, J. Russell Bailey, MD, Kevin Hsu, MD, Kevin R. Wheelan, MD, Jay O. Franklin, MD, Mark J. Mayotte, MS, Brian McHenry, MS and Teresa A. Whitman, PhD. Iowa Heart, Des Moines, IA, Mid-Carolina Cardiology, Charlotte, NC, Baylor University Medical Center, Dallas, TX and Medtronic, Inc., Fridley, MN. Background: Right ventricular (RV) pressure measurements may be useful for augmenting the diagnostic functionality of an ICD. We studied the feasibility of incorporating a pressure sensor on a dual-coil defibrillation lead. Lead handling and implant metrics of this apically-implanted pressure sensing defibrillation lead (aPSDL) were compared to a conventional defibrillation lead (Medtronic Model 6947). Methods: The aPSDL is an integrated-bipolar 10 Fr lead with a pressure sensor proximal to the RV coil. The sensor is positioned in the RV outflow tract (RVOT) by fixating the tip in the apex and pushing the RV coil along the trajectory between the apex and RVOT. Ten patients (pts) undergoing ICD implantation temporarily received the aPSDL prior to the Model 6947. Acute pacing and sensing thresholds and RV pressures were recorded. A 3-step binary search defibrillation threshold (DFT) was measured using RV⬎SVC⫹Can. Upon completion of aPSDL testing, the 6947 was implanted in the RV apex and identical data acquired. Results: Table shows electrophysiologic data. Conclusions: 1) aPSDL design had acceptable acute implant performance, but improvements in lead body stiffness and position of SVC coil are warranted. 2) Further study is needed to demonstrate chronic stability of this novel lead shape.
Background: Inadequate heart rate response to exercise, defined as an inability to achieve 85% of age predicted maximal heart rate, has been documented in many pacemaker patients. Changes in functional capacity due to beta-blocker (-b) administration may be attributed to alterations in autonomic function, leading to an impaired chronotropic response (CR). We studied correlates of impaired CR in a large cohort of patients newly implanted with a dual chamber pacemaker in the Limiting Chronotropic Incompetence for Pacemaker Recipients (LIFE) study. Methods: One-month post-implant, patients completed a baseline Chronotropic Assessment Exercise Protocol (CAEP) with rate response turned off. Chronotropic response was assessed by the metabolic-chronotropic relation (MCR) method which relates heart rate reserve and metabolic reserve. 518 patients had adequate 1-month exercise tests, (completed ⱖ 3 stages of exercise; achieved score ⱖ16 on the Rating of Perceived Exertion scale). A subset of 76 patients completed peak cardiopulmonary exercise (CPX) tests for Weber Functional Classification. Results: Univariate analyses showed significant associations between MCR slope and each of the following: New York Heart Association Class (NYHA; p⬍0.0001), Weber Functional Classification (p⬍0.006), and -blocker (-b) use (p⬍0.0001), with lower MCR slopes in those patients with decreased functional capacity and -b use. Within each functional class, patients on -b had lower average slopes compared to patients not on -b. There was a significant difference in MCR slopes between Weber Classes A and C (p⫽0.013). Conclusion: In pacemaker patients, there is an association between a decline in functional status, assessed by both NYHA and Weber classifications, and a reduction in CR. This reduction in CR is magnified by the use of -b within each functional class.
Acute Sensing, Pacing, and Defibrillation Thresholds for aPSDL and Model 6947 (N⫽10)
Lead
R-wave Pacing Amplitude Threshold (mV) (V)
Pacing Defibrillation Shock Impedance Threshold Impedance (ohms) (J) (ohms)
aPSDL 9.5 ⫾ 8.0 0.63 ⫾ 0.28 489 ⫾ 119 15.8 ⫾ 10.4 40 ⫾ 5 Model 15.3 ⫾ 7.0 0.67 ⫾ 0.15 740 ⫾ 174 12.6 ⫾ 8.6 41 ⫾ 5 6947 p-value* ⬍0.05 NS ⬍0.05 NS NS *Comparisons between aPSDL and Model 6947 by paired t-test
P5-95 ATRIAL PACING MAY BE DETRIMENTAL TO ATRIOVENTRICULAR DYSSYNCHRONY Mark S. Wathen, MD, Wade May, MD, C. Andrew Smith, MD, Neil Legaspie, RN and Pablo Saavedra, MD. Vanderbilt University, Nashville, TN. Intro: Recent studies have shown that right ventricular pacing causes dyssynchrony. Similarly, right atrial pacing can cause both interatrial and