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Determination of Heart Failure Patients Workload Intensity and Duration of Activities Using Implanted Cardiac Device
S50 Journal of Cardiac Failure Vol. 12 No. 6 Suppl. 2006 164
165
Determination of Heart Failure Patients Workload Intensity and Duration of Activities Using Implanted Cardiac Device F. Roosevelt Gilliam III1, Stuart D. Russell2, Daniel Bensimhon3, Paul Chase3, Donald Hopper4, Kenneth Beck4, Gerrard Carlson4, Jill Fricke4, Lemont Baker4; 1 Division of Cardiology, Duke University Medical Center, Durham, NC; 2Division of Cardiology, Johns Hopkins Hospital, Baltimore, MD; 3Heart Failure Clinic, LeBauer Cardiovascular Research Foundation, Greensboro, NC; 4Applied Research, Guidant Corporation, St. Paul, MN
Mechanical Support for Post-Transplant Isolated Right Heart Failure Margarita Camacho1, Raymond K. Wong2, Nicolle Kramer2; 1Department of Cardiothoracic Surgery, Newark Beth Israel Medical Center, Newark, NJ; 2 ABIOMED, Inc, Danvers, MA
Introduction: Determining the actual intensity and duration of physical activity could be useful for the management of heart failure (HF) patients. Pacemakers, implantable cardioverter defibrillators and cardiac resynchronization devices which contain accelerometers (XL), provide an opportunity to quantify both duration and intensity of a patient’s activities. Presently these devices provide one daily measurement and do not provide an estimate of energy expenditure. To quantify the intensity of patient activity, a relationship between known activity levels and XL data needs to be established. This study sought to document a relationship between the cardiac device XL measurements and data from metabolic exercise testing. Methods: The study population consisted of 17 patients. The patients performed up to three symptomlimited exercise studies (N 5 23 tests) at 1, 3 and 6 months after implantation of a CRT device. Using a modified Naughton exercise protocol with gas exchange, peak VO2 was converted to express a weight-relative unit (ml/kg/min) or metabolic equivalent (1 MET 5 ml/kg/min). During exercise, patients also wore an external single i-axis XL to collect the force of motion interval. Results: Patient’s MET levels had a high correlation with XL with an R2 5 0.7955. Any values less than 20 mG’s corresponds to a resting level of 1.0 to 1.5 METs. Conclusions: The demonstration of the relationship of XL values with METs could provide the ability to measure and monitor the frequency, duration and intensity of activity levels with implanted devices. Implanted devices may facilitate objective functional status monitoring in the heart failure patient.
Introduction: Severe global heart failure following transplantation can often be attributed to acute graft rejection. Despite left ventricular assist device (LVAD), or more likely, biventricular VAD support such patients seldom recover normal donor cardiac function. In contrast, isolated right ventricular (RV) failure, which occurs in 2-3% of post-transplant patients, is frequently caused by a combination of pulmonary hypertension and myocardial stunning, either due to emboli or inadequate preservation. These conditions are often reversible with RVAD therapy when inotropes and pulmonary vasodilators prove inadequate. In this retrospective study, we report outcomes of recent patients suffering from right-sided heart failure following a heart transplant who were implanted with RVADs. Methods: Between October of 2003 and March of 2006, a voluntary VAD data registry showed that 18 patients from 16 US centers were placed on VADs after experiencing right-sided heart failure following transplantation. These patients received right-sided-only VAD support with ABIOMED VADs, either the AB5000 (n 5 7) or the BVS 5000 (n 5 11). One patient’s outcome was pending and thus not included in this analysis. The patient population consisted of 69% males, with an average age of 50 years (range 20-68 years), and an average BSA of 1.9 m2 (range 1.5e2.7 m2). Results: Following post-transplant right heart failures, RVADs successfully supported 65% (11/17) of the patients, while 35% (6/17) expired on support. Of those who did not expire on support, 91% (n 5 10) were explanted from the device while one was re-transplanted. Three patients did not survive 30 days postexplant, thus the overall survival rate of patients who were either discharged or survived 30 days was 47% (8/17). The re-transplanted patient survived to discharge. Mean duration of support was 8 days (range 1-29 days). Conclusion: Success rates for heart transplantation can be improved when failing post-transplant RVs are supported with RVADs, thus giving medical therapy time to take effect and healing to occur. If donor heart recovery is not achieved, RVADs can provide continued support and prevent end-organ deterioration that would otherwise preclude re-transplantation.
166 Up-Regulation of Nerve Growth Factor Expression after Cardiac Resynchronization Therapy Yong-Mei Cha1, Robert F. Rea1, Win-Kuang Shen1, Samuel J. Asirvatham1, Paul A. Friedman1, David J. Bradley1, Peter A. Brady1, Thomas M. Munger1, Linda K. Hyberger1, Chinami Miyazaki1, Hongmei Li2, Lan S. Chen3, Peng-Sheng Chen2; 1 Cardiovascular Disease, Mayo Clinic, Rochester, MN; 2Cardiology, Cedars-Sinai Medical Center, Los Angeles, CA; 3Neurology, Childrens Hospital, Los Angeles, CA Background: Congestive heart failure (CHF) increases circulating catecholamine concentrations, causes heterogeneous cardiac denervation and reduces cardiac nerve growth factor (NGF) expression. We hypothesize that the responders to cardiac resynchronization therapy (CRT) would have an increased NGF expression. Methods: To test this hypothesis, we collected blood from radial artery and coronary sinus simultaneously before and 30-min after CRT for acute NGF response and peripheral blood before and 6-month after CRT for chronic NGF response in 8 patients (N 5 8). The NGF concentration was determined by ELISA. NYHA function class, distance of six-minute walk, and left ventricular ejection fraction (LVEF) were assessed before and 6-month after CRT. Results: The NGF concentrations (ng/ml) before and 30-min after CRT were 22.4 6 11.6, 22.9 6 13.6 (P 5 NS) in the coronary sinus, and 23.8 6 14.8, 32.6 6 21.3 (P 5 NS) in the radial artery, respectively. The transcardiac NGF concentration (difference between coronary sinus and artery) was -3.0 6 6.9 before and -9.7 6 18.4 30-min after CRT (P 5 NS). Six-month after commencement of CRT, the NGF concentration increased from 24.8 6 16.6 to 51.5 6 25.7 (p 5 0.047). The NYHA class in these patients improved from 3.1 6 0.4 to 1.9 6 0.5 (p 5 0.005), LV ejection fraction increased from 22.9 6 3.8% to 34.5 6 12.9% (p 5 0.05). The distance of 6-min walk increased from 301 6 87 meter to 425 6 103 meter (p 5 0.03). We conclude that there are no significant changes of cardiac NGF expression immediately after CRT. However, a significant increase of plasma NGF concentration was observed at 6-month follow up, along with improvement in CHF status. These findings are consistent with the hypothesis that effective nonpharmacological anti-CHF therapy is associated with up-regulation of NGF expression.
165
Determination of Heart Failure Patients Workload Intensity and Duration of Activities Using Implanted Cardiac Device F. Roosevelt Gilliam III1, Stuart D. Russell2, Daniel Bensimhon3, Paul Chase3, Donald Hopper4, Kenneth Beck4, Gerrard Carlson4, Jill Fricke4, Lemont Baker4; 1 Division of Cardiology, Duke University Medical Center, Durham, NC; 2Division of Cardiology, Johns Hopkins Hospital, Baltimore, MD; 3Heart Failure Clinic, LeBauer Cardiovascular Research Foundation, Greensboro, NC; 4Applied Research, Guidant Corporation, St. Paul, MN
Mechanical Support for Post-Transplant Isolated Right Heart Failure Margarita Camacho1, Raymond K. Wong2, Nicolle Kramer2; 1Department of Cardiothoracic Surgery, Newark Beth Israel Medical Center, Newark, NJ; 2 ABIOMED, Inc, Danvers, MA
Introduction: Determining the actual intensity and duration of physical activity could be useful for the management of heart failure (HF) patients. Pacemakers, implantable cardioverter defibrillators and cardiac resynchronization devices which contain accelerometers (XL), provide an opportunity to quantify both duration and intensity of a patient’s activities. Presently these devices provide one daily measurement and do not provide an estimate of energy expenditure. To quantify the intensity of patient activity, a relationship between known activity levels and XL data needs to be established. This study sought to document a relationship between the cardiac device XL measurements and data from metabolic exercise testing. Methods: The study population consisted of 17 patients. The patients performed up to three symptomlimited exercise studies (N 5 23 tests) at 1, 3 and 6 months after implantation of a CRT device. Using a modified Naughton exercise protocol with gas exchange, peak VO2 was converted to express a weight-relative unit (ml/kg/min) or metabolic equivalent (1 MET 5 ml/kg/min). During exercise, patients also wore an external single i-axis XL to collect the force of motion interval. Results: Patient’s MET levels had a high correlation with XL with an R2 5 0.7955. Any values less than 20 mG’s corresponds to a resting level of 1.0 to 1.5 METs. Conclusions: The demonstration of the relationship of XL values with METs could provide the ability to measure and monitor the frequency, duration and intensity of activity levels with implanted devices. Implanted devices may facilitate objective functional status monitoring in the heart failure patient.
Introduction: Severe global heart failure following transplantation can often be attributed to acute graft rejection. Despite left ventricular assist device (LVAD), or more likely, biventricular VAD support such patients seldom recover normal donor cardiac function. In contrast, isolated right ventricular (RV) failure, which occurs in 2-3% of post-transplant patients, is frequently caused by a combination of pulmonary hypertension and myocardial stunning, either due to emboli or inadequate preservation. These conditions are often reversible with RVAD therapy when inotropes and pulmonary vasodilators prove inadequate. In this retrospective study, we report outcomes of recent patients suffering from right-sided heart failure following a heart transplant who were implanted with RVADs. Methods: Between October of 2003 and March of 2006, a voluntary VAD data registry showed that 18 patients from 16 US centers were placed on VADs after experiencing right-sided heart failure following transplantation. These patients received right-sided-only VAD support with ABIOMED VADs, either the AB5000 (n 5 7) or the BVS 5000 (n 5 11). One patient’s outcome was pending and thus not included in this analysis. The patient population consisted of 69% males, with an average age of 50 years (range 20-68 years), and an average BSA of 1.9 m2 (range 1.5e2.7 m2). Results: Following post-transplant right heart failures, RVADs successfully supported 65% (11/17) of the patients, while 35% (6/17) expired on support. Of those who did not expire on support, 91% (n 5 10) were explanted from the device while one was re-transplanted. Three patients did not survive 30 days postexplant, thus the overall survival rate of patients who were either discharged or survived 30 days was 47% (8/17). The re-transplanted patient survived to discharge. Mean duration of support was 8 days (range 1-29 days). Conclusion: Success rates for heart transplantation can be improved when failing post-transplant RVs are supported with RVADs, thus giving medical therapy time to take effect and healing to occur. If donor heart recovery is not achieved, RVADs can provide continued support and prevent end-organ deterioration that would otherwise preclude re-transplantation.
166 Up-Regulation of Nerve Growth Factor Expression after Cardiac Resynchronization Therapy Yong-Mei Cha1, Robert F. Rea1, Win-Kuang Shen1, Samuel J. Asirvatham1, Paul A. Friedman1, David J. Bradley1, Peter A. Brady1, Thomas M. Munger1, Linda K. Hyberger1, Chinami Miyazaki1, Hongmei Li2, Lan S. Chen3, Peng-Sheng Chen2; 1 Cardiovascular Disease, Mayo Clinic, Rochester, MN; 2Cardiology, Cedars-Sinai Medical Center, Los Angeles, CA; 3Neurology, Childrens Hospital, Los Angeles, CA Background: Congestive heart failure (CHF) increases circulating catecholamine concentrations, causes heterogeneous cardiac denervation and reduces cardiac nerve growth factor (NGF) expression. We hypothesize that the responders to cardiac resynchronization therapy (CRT) would have an increased NGF expression. Methods: To test this hypothesis, we collected blood from radial artery and coronary sinus simultaneously before and 30-min after CRT for acute NGF response and peripheral blood before and 6-month after CRT for chronic NGF response in 8 patients (N 5 8). The NGF concentration was determined by ELISA. NYHA function class, distance of six-minute walk, and left ventricular ejection fraction (LVEF) were assessed before and 6-month after CRT. Results: The NGF concentrations (ng/ml) before and 30-min after CRT were 22.4 6 11.6, 22.9 6 13.6 (P 5 NS) in the coronary sinus, and 23.8 6 14.8, 32.6 6 21.3 (P 5 NS) in the radial artery, respectively. The transcardiac NGF concentration (difference between coronary sinus and artery) was -3.0 6 6.9 before and -9.7 6 18.4 30-min after CRT (P 5 NS). Six-month after commencement of CRT, the NGF concentration increased from 24.8 6 16.6 to 51.5 6 25.7 (p 5 0.047). The NYHA class in these patients improved from 3.1 6 0.4 to 1.9 6 0.5 (p 5 0.005), LV ejection fraction increased from 22.9 6 3.8% to 34.5 6 12.9% (p 5 0.05). The distance of 6-min walk increased from 301 6 87 meter to 425 6 103 meter (p 5 0.03). We conclude that there are no significant changes of cardiac NGF expression immediately after CRT. However, a significant increase of plasma NGF concentration was observed at 6-month follow up, along with improvement in CHF status. These findings are consistent with the hypothesis that effective nonpharmacological anti-CHF therapy is associated with up-regulation of NGF expression.