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Improved Response to Cardiac Resynchronization Therapy through Optimization of Atrioventricular and Interventricular Delays Using Acoustic Cardiography
The 11th Annual Scientific Meeting
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hemoximeter. Hct levels were increased by adding packed red blood cells and decreased by replacing blood with colloid fluid. O2 variations were repeated at each Hct level. Results: Pooled mean absolute errors in SvO2 and Hct estimation across all animal studies and sensors closely resembled error values from the benchtop studies (Figures A and B). The overall errors, averaged over all O2 saturation and Hct ranges were 5.56 6 2.36% in animals and 2.22 6 1.93% in benchtop for SvO2 estimation and 3.91 6 3.83% in animals and 1.53 6 1.24% in benchtop for Hct estimation. Conclusion: A novel SvO2 and Hct sensor was developed and tested in vitro and in vivo. The sensor was able to measure SvO2 and Hct at clinically relevant O2 levels with a high level of accuracy. These findings suggest the suitability of this sensor as a tool for management of HF and anemia.
170 Improved Response to Cardiac Resynchronization Therapy through Optimization of Atrioventricular and Interventricular Delays Using Acoustic Cardiography Stefan Toggweiler1, Michel Zuber1, Richard Kobza1, Markus Roos1, Peiman Jamshidi1, Paul Erne1; 1Division of Cardiology, Kantonsspital Luzern, Lucerne, Switzerland
169 Pilot Investigation of Cardiogenic Impedance during Heart Failure Induction Using a New Prototype ICD Yelena Nabutovsky1, Mihir Naware1, Jeff Siou1, Ajit Pillai1, Uday Illindala1, Nils Holmstrom1, Andreas Blomqvist1, Malin Ohlander1, Dan Gutfinger1, Neil Eigler1, Miriam Rademaker2, Chris Charles2, Richard Troughton2, Dorin Panescu1; 1St. Jude Medical, Sylmar, CA; 2Christchurch School of Medicine and Health Sciences, Christchurch, New Zealand Introduction: Measurements of cardiogenic impedance (Zc), as defined by beat-tobeat impedance variations, may facilitate early detection of heart failure (HF). We evaluated changes in Zc waveform amplitude and morphology during progression of HF. Methods: A biventricular prototype ICD (St. Jude Medical) with RA, RV, LV bipolar leads and a single shock RV coil were implanted in 3 dogs (D) and 3 sheep (S). Continuous Zc signals were recorded using small current pulses (128 Hz) delivered over 3 bipolar (LVRing-RARing (V1), RVRing-LVRing (V2), RVRingeRVTip (V3)) and 1 quadripolar (RV-LV (V4)) vector configurations. Following 35 weeks of lead maturation, HF was induced by RV pacing at 250 bpm in D and 220 bpm in S for 2-4 weeks. Left ventricular ejection fraction (LVEF) and end diastolic pressure (LVEDP) were collected every 2 weeks in D and daily mean left atrial pressure (LAP) was recorded in S, using an implanted LAP sensor (HeartPOD, St. Jude Medical). Zc peak-to-peak amplitude (ppA) and fractionation index (FI) were trended daily in all vectors. FI was defined as average number of Zc notches (a dip in waveform O 20% of ppA) per heart beat (Fig A). Results: All animals entered HF, as indicated by a reduction in LVEF from 42.9 6 8.6 to 23.5 6 9.6% and an increase in LVEDP from 6 6 2.6 to 22 6 12.2 mmHg in D and an increase in LAP from 8.1 6 3.5 to 22.2 6 8.4 mmHg in S. A visible morphology change in Zc occurred within 1-2 days of pacing, progressing throughout HF induction, as quantified by ppA reduction and FI increase in all vectors (Fig B). There was a significant (p ! 0.05) inverse correlation between LAP and ppA in vectors V2, V3, and V4 (Fig C). Conclusion: Onset of HF caused a significant decrease in ppA and an increase in FI in all Zc vectors in all animals. In S, a significant inverse correlation between ppA and LAP was observed in three Zc vectors. Our results warrant further investigation of Zc ppA and FI for early HF detection and monitoring.
Introduction: Acoustic cardiographic parameters offer non-invasive surrogates for hemodynamically relevant descriptors of LV function. Our purpose was to determine the utility of acoustic cardiography for the optimization of atrioventricular (AV) and interventricular (VV) delays in cardiac resynchronization therapy (CRT). Hypothesis: The optimization of AV and VV delays using acoustic cardiography leads to additional objective improvements in LV function in patients with CRT. Methods: Spiroergometry and 2D/3D echocardiography were used to assess cardiac performance for standard (‘‘out-of-the-box’’) settings (AV 120 ms, VV 0 ms) versus optimal settings (determined by acoustic cardiography). Cardiac performance measurements were carried out six weeks after settings were modified. Optimal AV/VV settings were determined based on the lowest electromechanical activation time (EMAT, the time from the onset of QRS to the mitral valve component of the first heart sound) as provided by acoustic cardiography (Audicor, Inovise Medical, Inc). Statistical analysis was performed using a paired two-tailed student’s t-test. Results: We enrolled 14 patients (86% male, mean age 64 6 9 years), mean time since implant 15 6 18 months. Mean optimized delays were 161 6 65 ms and LV 10 6 25 ms before RV for AV and VV delays, respectively. In comparison to baseline settings, AV/VV delay optimization with acoustic cardiography significantly improved cardiac performance parameters as shown in table 1. Conclusions: AV and VV delay optimization by acoustic cardiography produces significant improvements in objective clinical and hemodynamic parameters in comparison to typical ‘‘outof-the-box’’ settings.
Cardiac performance parameters with standard- and optimized AV/VV-delays Parameter NYHA class Work Capacity (Watt) Peak Oxygen Uptake (ml/min/kg) Peak Oxygen Pulse (ml/min/beat) 3D EF (%) 3D ESV (ml) LVOT-VTI (cm)
Baseline Settings Optimized Settings p-value 2.4 96 20.4 13.5 27.5 144 10.8
6 6 6 6 6 6 6
0.5 36 6.3 4.3 12.8 82 3.7
2.1 101 22.4 14.8 34.5 126 13.0
6 6 6 6 6 6 6
0.6 35 7.3 4.5 10.4 65 4.0
! ! ! ! ! ! !
0.05 0.01 0.01 0.05 0.01 0.05 0.05
Data presented as mean 6 SD; EF 5 ejection fraction; ESV 5 end-systolic volume; LVOT-VTI 5 velocity-time integral in left ventricular outflow tract.
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hemoximeter. Hct levels were increased by adding packed red blood cells and decreased by replacing blood with colloid fluid. O2 variations were repeated at each Hct level. Results: Pooled mean absolute errors in SvO2 and Hct estimation across all animal studies and sensors closely resembled error values from the benchtop studies (Figures A and B). The overall errors, averaged over all O2 saturation and Hct ranges were 5.56 6 2.36% in animals and 2.22 6 1.93% in benchtop for SvO2 estimation and 3.91 6 3.83% in animals and 1.53 6 1.24% in benchtop for Hct estimation. Conclusion: A novel SvO2 and Hct sensor was developed and tested in vitro and in vivo. The sensor was able to measure SvO2 and Hct at clinically relevant O2 levels with a high level of accuracy. These findings suggest the suitability of this sensor as a tool for management of HF and anemia.
170 Improved Response to Cardiac Resynchronization Therapy through Optimization of Atrioventricular and Interventricular Delays Using Acoustic Cardiography Stefan Toggweiler1, Michel Zuber1, Richard Kobza1, Markus Roos1, Peiman Jamshidi1, Paul Erne1; 1Division of Cardiology, Kantonsspital Luzern, Lucerne, Switzerland
169 Pilot Investigation of Cardiogenic Impedance during Heart Failure Induction Using a New Prototype ICD Yelena Nabutovsky1, Mihir Naware1, Jeff Siou1, Ajit Pillai1, Uday Illindala1, Nils Holmstrom1, Andreas Blomqvist1, Malin Ohlander1, Dan Gutfinger1, Neil Eigler1, Miriam Rademaker2, Chris Charles2, Richard Troughton2, Dorin Panescu1; 1St. Jude Medical, Sylmar, CA; 2Christchurch School of Medicine and Health Sciences, Christchurch, New Zealand Introduction: Measurements of cardiogenic impedance (Zc), as defined by beat-tobeat impedance variations, may facilitate early detection of heart failure (HF). We evaluated changes in Zc waveform amplitude and morphology during progression of HF. Methods: A biventricular prototype ICD (St. Jude Medical) with RA, RV, LV bipolar leads and a single shock RV coil were implanted in 3 dogs (D) and 3 sheep (S). Continuous Zc signals were recorded using small current pulses (128 Hz) delivered over 3 bipolar (LVRing-RARing (V1), RVRing-LVRing (V2), RVRingeRVTip (V3)) and 1 quadripolar (RV-LV (V4)) vector configurations. Following 35 weeks of lead maturation, HF was induced by RV pacing at 250 bpm in D and 220 bpm in S for 2-4 weeks. Left ventricular ejection fraction (LVEF) and end diastolic pressure (LVEDP) were collected every 2 weeks in D and daily mean left atrial pressure (LAP) was recorded in S, using an implanted LAP sensor (HeartPOD, St. Jude Medical). Zc peak-to-peak amplitude (ppA) and fractionation index (FI) were trended daily in all vectors. FI was defined as average number of Zc notches (a dip in waveform O 20% of ppA) per heart beat (Fig A). Results: All animals entered HF, as indicated by a reduction in LVEF from 42.9 6 8.6 to 23.5 6 9.6% and an increase in LVEDP from 6 6 2.6 to 22 6 12.2 mmHg in D and an increase in LAP from 8.1 6 3.5 to 22.2 6 8.4 mmHg in S. A visible morphology change in Zc occurred within 1-2 days of pacing, progressing throughout HF induction, as quantified by ppA reduction and FI increase in all vectors (Fig B). There was a significant (p ! 0.05) inverse correlation between LAP and ppA in vectors V2, V3, and V4 (Fig C). Conclusion: Onset of HF caused a significant decrease in ppA and an increase in FI in all Zc vectors in all animals. In S, a significant inverse correlation between ppA and LAP was observed in three Zc vectors. Our results warrant further investigation of Zc ppA and FI for early HF detection and monitoring.
Introduction: Acoustic cardiographic parameters offer non-invasive surrogates for hemodynamically relevant descriptors of LV function. Our purpose was to determine the utility of acoustic cardiography for the optimization of atrioventricular (AV) and interventricular (VV) delays in cardiac resynchronization therapy (CRT). Hypothesis: The optimization of AV and VV delays using acoustic cardiography leads to additional objective improvements in LV function in patients with CRT. Methods: Spiroergometry and 2D/3D echocardiography were used to assess cardiac performance for standard (‘‘out-of-the-box’’) settings (AV 120 ms, VV 0 ms) versus optimal settings (determined by acoustic cardiography). Cardiac performance measurements were carried out six weeks after settings were modified. Optimal AV/VV settings were determined based on the lowest electromechanical activation time (EMAT, the time from the onset of QRS to the mitral valve component of the first heart sound) as provided by acoustic cardiography (Audicor, Inovise Medical, Inc). Statistical analysis was performed using a paired two-tailed student’s t-test. Results: We enrolled 14 patients (86% male, mean age 64 6 9 years), mean time since implant 15 6 18 months. Mean optimized delays were 161 6 65 ms and LV 10 6 25 ms before RV for AV and VV delays, respectively. In comparison to baseline settings, AV/VV delay optimization with acoustic cardiography significantly improved cardiac performance parameters as shown in table 1. Conclusions: AV and VV delay optimization by acoustic cardiography produces significant improvements in objective clinical and hemodynamic parameters in comparison to typical ‘‘outof-the-box’’ settings.
Cardiac performance parameters with standard- and optimized AV/VV-delays Parameter NYHA class Work Capacity (Watt) Peak Oxygen Uptake (ml/min/kg) Peak Oxygen Pulse (ml/min/beat) 3D EF (%) 3D ESV (ml) LVOT-VTI (cm)
Baseline Settings Optimized Settings p-value 2.4 96 20.4 13.5 27.5 144 10.8
6 6 6 6 6 6 6
0.5 36 6.3 4.3 12.8 82 3.7
2.1 101 22.4 14.8 34.5 126 13.0
6 6 6 6 6 6 6
0.6 35 7.3 4.5 10.4 65 4.0
! ! ! ! ! ! !
0.05 0.01 0.01 0.05 0.01 0.05 0.05
Data presented as mean 6 SD; EF 5 ejection fraction; ESV 5 end-systolic volume; LVOT-VTI 5 velocity-time integral in left ventricular outflow tract.