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Use of implanted CRT device diagnostics to determine the risk of heart failure decompensation
The 7th Annual Scientific Meeting
•
HFSA
S97
360
361
Clinical Benefits of Low Frequency Respiratory Pacing in Heart Failure Patients Gianfranco Parati,1,2 Grzegorz Bilo,1,2 Alberto Maronati,2 Fabio Glavina,2 Guido Ongaro,2 Ariela Alter,3 Benjamin Gavish,3 Giovanna Branzi,2 Claudio Borghi,4 Giuseppe Mancia1,2—1Dept of Clinical Medicine, Prevention and Applied Biotechnology, University of Milano-Bicocca, Milan, Italy; 2II Cardiology Unit, S. Luca Hospital, Istitituto Auxologico Italiano, Milano, Milan, Italy; 3InterCure Ltd., Lod, Israel; 4Clinica Medica, University of Bologna, Bologna, Italy
Brain Natriuretic Peptide (BNP) Is Useful as a Biochemical Predictor of Contractile Reserve during Dobutamine Stress Echocardiogram Ann T. Tong,1 Daniel Lenihan,1 Jessica Tristan,1 Jean-Bernard Durand1— 1 Cardiology, MD Anderson Cancer Center, Houston, TX
Background: Slow breathing exercise (SBE) has been shown to sensitize cardiovascular reflexes, to reduce sympathetic activity1 and to lower blood pressure. Preliminary data suggest that SBE can be useful also in improving the autonomic modulation and symptoms of congestive heart failure (CHF) patients. This pilot study was designed to explore the clinical effects in CHF patients of SBE obtained through a respiratory-pacing device, when applied in the home setting. Patients: 12 CHF patients in stable clinical condition for at least 1 month, were recruited from two outpatient hospital clinics: age 67 ⫾ 9 y, NYHA class II to III, BMI 27 ⫾ 5, HR 68 ⫾ 14 and BP 122 ⫾ 22/ 70 ⫾ 12 mmHg. Intervention: Slow and deep breathing was achieved by synchronizing patient’s inspiration and expiration with guiding tones, generated by a respiratory-pacing device (InterCure, Israel) controlled by a respiration sensor. The device adjusts interactively the pacing frequency to the patient’s ability to slow his/her breathing and stores automatically compliance and performance data including breath by breath respiration rate. Design: Open-label, including 2 baseline visits performed one week apart to ensure basal stability of clinical parameters, followed by a 9-week intervention period with 3 follow-up visits every 3 weeks. Patients received the device and a short training during the 2nd baseline visit and were requested to use the device at home twice daily (morning and evening) during the 9-week period. Each intervention included a 15-minute respiratory pacing session preceded by 3 minutes of spontaneous breathing. Clinical outcomes included changes between baseline and last visit in quality of life (QOL - by Minnesota Living With HF Questionnaire), 6-minute walking distance, ejection fraction (EF) and pulmonary arterial pressure (PAP) both measured by echocardiography. Results: In all patients pharmacological treatment remained unchanged throughout the study. No change in clinical parameters was observed between the 2 baseline visits. Significant improvements from baseline to last visit, after 9-week SBE at home, were observed in CHF symptoms and signs as quantified by QOL score (from 36 to 24 points, p ⬍ 0.001), 6minute walking distance, if initially less than normal (from 426 to 480 m, p ⬍ 0.05), ejection fraction (from 35% to 40%, p ⬍ 0.05) and PAP (from 46 to 36 mmHg, p ⬍ 0.05). Patients showed high compliance with SBE (80% of the requested 14 sessions per week were regularly performed) and easily learned how to pace down respiration rate (from 13.5 to 7.1 breaths/min in the first two sessions, p ⬍ 0.001). Conclusion: Our pilot study shows that device-paced slow breathing may represent a simple intervention able to provide additional benefits to CHF patients over and above those offered by state-of-the-art pharmacological treatment. These findings however need to be confirmed and extended by a larger-scale study.
Background: Dobutamine Stress Echocardiogram (DSE) has been used to assess myocardial contractile reserve in both ischemic and dilated cardiomyopathy. A higher inotropic reserve has been shown to be associated with better prognosis and improvement in left ventricular ejection fraction (LV EF) in patients with revascularization (ischemic) or beta blocker therapy (dilated). In patients with chemotherapy induced cardiomyopathy (CIM), the predictive power of DSE is not known. Also, DSE can be technically challenging to detect contractile improvement and can be limited by inter- and intra-observer variability. Brain Natriuretic Peptide (BNP), a hormone secreted by the ventricular myocardium in response to volume overload, correlates with symptoms and prognosis in heart failure patients. It is unknown whether BNP obtained before and after DSE identifies contractile reserve in patients with cardiomyopathy. Methods: 29 consecutive patients with LVEF ⬍45% were consented to undergo DSE. Dobutamine was started at 5 mcg/kg/min, with dose increasing every 3 minutes up to 40 mcg/kg/min or when 85% of maximal predicted heart rate was achieved. A BNP level was at baseline and at peak dobutamine. All DSE studies were reviewed and quantitated by a single observer. LVEF is calculated by Method of Discs. Results: The patients are stratified into 4 groups: 1) Baseline BNP ⬎100pg/ml and increased BNP post DSE 2) Baseline BNP ⬎100pg/ml and decreased BNP post DSE 3) Baseline BNP ⬍ 100pg/ ml and increased BNP post DSE 4) Baseline BNP ⬍ 100pg/ml and decreased BNP post DSE. The correlation between BNP and contractile reserve are listed in Table 1. In general, patients in Group 1 did not have a significant contractile response with DSE whereas patients in Group 2 had a significant increase in LVEF with DSE. Most patients in Group 3 did not have a significant improvement in LVEF but 2 patients did have significant improvement in LVEF. Patients in Group 4 had a significant improvement in their LVEF. Improvement in LVEF and NYHA after treatment with beta blocker were noted in most patients except Group 1 patients. Conclusion: In assessing myocardial contractile reserve, the decrease in BNP levels after DSE, is correlated with the presence of viability. There is a trend that the greater the decrease in BNP, the greater the contractile reserve is seen with DSE and the greater improvement in LVEF on therapy. This is the first biochemical marker for viability. BNP therefore can help identify myocardial contractile reserve in conjunction to the DSE results, and maybe especially helpful in the difficult to image patients. Furthermore, in the cancer patients with chemotherapy induced cardiomyopathy, BNP can be used to predict recovery of cardiac function. CORRELATION OF BNP WITH CONTRACTILE RESERVE
1 Parati G, Izzo JL Jr, Gavish B. Respiration and Blood Pressure,in Hypertension Primer, 3rd ed.. (JL Izzo and HR Black, Eds). AHA 2003, pp.117-120.
GROUP GROUP GROUP GROUP
1(N ⫽ 6) 2(N ⫽ 12) 3(N ⫽ 5) 4(N ⫽ 6)
PRE-BNP
POST-BNP
PRE-LVEF
POST-LVEF
286.5+/⫺190.9 490.3+/⫺328.2 47.3+/⫺34.4 32.3+/⫺28.4
427.3+/⫺275.1 367.5+/⫺295.0 78.7+/⫺80.4 23.8+/⫺22.6
32.2+/⫺7.7 35.5+/⫺10.9 34.2+/ 12.6 41.2+/⫺5.0
31.2+/⫺8.2 47.7+/⫺12.0 40.2+/⫺16.0 57.3+/⫺6.7
362
363
Cardiologist Use of ACE Inhibitors Versus Angiotensin Receptor Blocking Agents for Heart Failure Mary N. Walsh,1 Cynthia D. Adams1—1CardiAction, The Care Group, LLC, Indianapolis, IN
Use of Implanted CRT Device Diagnostics to Determine the Risk of Heart Failure Decompensation William T. Abraham,1 Andrew L. Smith,2 Angel R. Leon,2 Karen J. Kleckner,3 Melissa M. Rhodes3—1Division of Cardiology, The Ohio State University, Columbus, OH; 2 Emory Univ. School of Medicine, Atlanta, GA; 3Medtronic, Inc., Minneapolis, MN
Background: The mortality and morbidity benefits associated with the use of angiotensin converting enzyme inhibitors (ACE) in heart failure (HF) are well established. However, 10-20% of patients given ACE are intolerant due to cough. Angiotensin II receptor blocking agents (ARB) have been promoted as better tolerated alternatives to ACE due to the absence of cough as a side effect. Because of this, prescribing practices may be swayed toward ARB use in spite of the overwhelming data supporting use of ACE for first-line HF treatment. The current American College of Cardiology/American Heart Association Guidelines for the Evaluation and Management of Chronic Heart Failure in the Adult states that ARB should not be considered as equivalent to ACE, and should not be used without prior trial of ACE or substituted for ACE in pts who are tolerating therapy without difficulty. Purpose: The purpose of this study was to examine the prescribing practices, as pertaining to the use of ACE and ARB for HF, among individual cardiologists in a large, single specialty, private practice. Methods: The electronic medical record (EMR) system at a large urban cardiology practice was queried to report the use of ACE and ARB in patients (pts) with diagnoses of HF or cardiomyopathy. The ability of the EMR to select pts by diagnosis, sort by physician, and identify medications prescribed and/or dosage changes made at specific visits, enabled examination of variability of prescribing practices. Pts in whom the specific provider could not be identified, and pts of providers having fewer than 10 pts in the sample were excluded from analysis. Results: 1956 pts with appropriate diagnoses were examined. Of these, 75% were on either an ACE or ARB agent (ACE/ARB). Among subspecialists (HF cardiologists, electrophysiologists, interventional, invasive, and non-invasive cardiologists), HF cardiologists demonstrated the highest ACE/ARB use (83.3%), followed by electrophysiologists (72.3%), non-invasive and interventional cardiologists (both at 71.4%), and invasive cardiologists (65.2%). Among pts on these agents, 80% were on ACE, and 20% were on ARB. ACE use by individual cardiologists ranged from 65% to 97%, and ARB use from 3% to 35%. ARB use did not vary between non-HF cardiologists seeing higher versus lower volumes of HF pts. However, when compared by subspecialty, non-invasive cardiologists tended to be the highest users of ARB (26.9%) followed by interventionalists (21.0%), invasive cardiologists (17.6%), and electrophysiologists (17.1%). The lowest ARB prescribers were the HF specialists (16.8%). Conclusion: The percentage of HF pts receiving therapy with either ACE or ARB was lower than may be expected, at only 75% of the study sample. However, practice patterns in this group reflect an appropriate preference for ACE over ARB in the treatment of HF, with the expected 20% of pts being prescribed ARB. There was wide variability among individual cardiologists in various subspecialties. HF specialists tended to be higher prescribers of ACE/ARB therapy overall, but chose ARB over ACE less frequently than cardiologists in other subspecialties.
Background: Newer implantable cardiac resynchronization therapy (CRT) devices are able to measure and record average night heart rate, heart rate variability and patient activity on a daily basis. The purpose of this retrospective analysis was to assess whether these device measures may be useful for managing patients with heart failure. Methods: We reviewed heart failure decompensation events which included heart failure hospitalizations in a study of CRT for NYHA III/IV heart failure pts without traditional pacing indications (U.S. InSync III trial). Device based heart failure diagnostics were not used to make clinical decisions. Two analyses were performed: 1) the average daily values from one month post implant to the six month follow-up for average night heart rate, heart rate variability and physical activity were compared for pts with and without heart failure decompensation and 2) the ability of night heart rate, heart rate variability and physical actvity to predict heart failure hospitalization was assessed by comparing the weekly average of weeks starting 1 week and 4 weeks prior to the heart failure hospitalization for patients with a hospitalization at least 40 days post implant. Results: Of the 255 patients for whom device data were available, 65 experienced at least one heart failure decompensation. There were 33 patients with a heart failure hospitalization at least 40 days post implant. There were no statistical differences in the following baseline characteristics between the Heart Failure Decompensation and No Heart Failure Decompensation groups (age, gender, etiology, NYHA, LVEF, LVEDD, beta blocker usage), while the No Heart Failure Decompensation group had a slightly wider QRS (167 ms vs. 160 ms, p ⫽ 0.02). As shown in the table, patients with Heart Failure Decompensation have higher average night heart rate, lower heart rate variability and less physical actvity, as measured by the device on a daily basis. Modest, but statistically significant, changes in heart rate variability and physical activity occur a week prior to hospitalization.
Diagnostic Night Heart Rate (bpm) Heart Rate Variability (ms) Physical Activity (hr)
No Heart Failure Decompensation
Heart Failure Decompensation
P-value
Heart Failure Hospitalization -4 Weeks
Heart Failure Hospitalization -1 Week
69.8 ⫾ 9.3
75.2 ⫾ 9.9
P-value
0.0001
78.3 ⫾ 11.4
79.8 ⫾ 12.4
87.6 ⫾ 24.2
0.15
75.4 ⫾ 23.2
0.0008
66.5 ⫾ 21.1
60.6 ⫾ 24.4
0.03
3.1 ⫾ 1.5
2.4 ⫾ 1.2
0.0003
2.6 ⫾ 1.2
2.1 ⫾ 1.1
0.005
Conclusions: CRT devices with these diagnostic capabilities may offer objective measures to help determine which patients warrant closer supervision of their heart failure status.
•
HFSA
S97
360
361
Clinical Benefits of Low Frequency Respiratory Pacing in Heart Failure Patients Gianfranco Parati,1,2 Grzegorz Bilo,1,2 Alberto Maronati,2 Fabio Glavina,2 Guido Ongaro,2 Ariela Alter,3 Benjamin Gavish,3 Giovanna Branzi,2 Claudio Borghi,4 Giuseppe Mancia1,2—1Dept of Clinical Medicine, Prevention and Applied Biotechnology, University of Milano-Bicocca, Milan, Italy; 2II Cardiology Unit, S. Luca Hospital, Istitituto Auxologico Italiano, Milano, Milan, Italy; 3InterCure Ltd., Lod, Israel; 4Clinica Medica, University of Bologna, Bologna, Italy
Brain Natriuretic Peptide (BNP) Is Useful as a Biochemical Predictor of Contractile Reserve during Dobutamine Stress Echocardiogram Ann T. Tong,1 Daniel Lenihan,1 Jessica Tristan,1 Jean-Bernard Durand1— 1 Cardiology, MD Anderson Cancer Center, Houston, TX
Background: Slow breathing exercise (SBE) has been shown to sensitize cardiovascular reflexes, to reduce sympathetic activity1 and to lower blood pressure. Preliminary data suggest that SBE can be useful also in improving the autonomic modulation and symptoms of congestive heart failure (CHF) patients. This pilot study was designed to explore the clinical effects in CHF patients of SBE obtained through a respiratory-pacing device, when applied in the home setting. Patients: 12 CHF patients in stable clinical condition for at least 1 month, were recruited from two outpatient hospital clinics: age 67 ⫾ 9 y, NYHA class II to III, BMI 27 ⫾ 5, HR 68 ⫾ 14 and BP 122 ⫾ 22/ 70 ⫾ 12 mmHg. Intervention: Slow and deep breathing was achieved by synchronizing patient’s inspiration and expiration with guiding tones, generated by a respiratory-pacing device (InterCure, Israel) controlled by a respiration sensor. The device adjusts interactively the pacing frequency to the patient’s ability to slow his/her breathing and stores automatically compliance and performance data including breath by breath respiration rate. Design: Open-label, including 2 baseline visits performed one week apart to ensure basal stability of clinical parameters, followed by a 9-week intervention period with 3 follow-up visits every 3 weeks. Patients received the device and a short training during the 2nd baseline visit and were requested to use the device at home twice daily (morning and evening) during the 9-week period. Each intervention included a 15-minute respiratory pacing session preceded by 3 minutes of spontaneous breathing. Clinical outcomes included changes between baseline and last visit in quality of life (QOL - by Minnesota Living With HF Questionnaire), 6-minute walking distance, ejection fraction (EF) and pulmonary arterial pressure (PAP) both measured by echocardiography. Results: In all patients pharmacological treatment remained unchanged throughout the study. No change in clinical parameters was observed between the 2 baseline visits. Significant improvements from baseline to last visit, after 9-week SBE at home, were observed in CHF symptoms and signs as quantified by QOL score (from 36 to 24 points, p ⬍ 0.001), 6minute walking distance, if initially less than normal (from 426 to 480 m, p ⬍ 0.05), ejection fraction (from 35% to 40%, p ⬍ 0.05) and PAP (from 46 to 36 mmHg, p ⬍ 0.05). Patients showed high compliance with SBE (80% of the requested 14 sessions per week were regularly performed) and easily learned how to pace down respiration rate (from 13.5 to 7.1 breaths/min in the first two sessions, p ⬍ 0.001). Conclusion: Our pilot study shows that device-paced slow breathing may represent a simple intervention able to provide additional benefits to CHF patients over and above those offered by state-of-the-art pharmacological treatment. These findings however need to be confirmed and extended by a larger-scale study.
Background: Dobutamine Stress Echocardiogram (DSE) has been used to assess myocardial contractile reserve in both ischemic and dilated cardiomyopathy. A higher inotropic reserve has been shown to be associated with better prognosis and improvement in left ventricular ejection fraction (LV EF) in patients with revascularization (ischemic) or beta blocker therapy (dilated). In patients with chemotherapy induced cardiomyopathy (CIM), the predictive power of DSE is not known. Also, DSE can be technically challenging to detect contractile improvement and can be limited by inter- and intra-observer variability. Brain Natriuretic Peptide (BNP), a hormone secreted by the ventricular myocardium in response to volume overload, correlates with symptoms and prognosis in heart failure patients. It is unknown whether BNP obtained before and after DSE identifies contractile reserve in patients with cardiomyopathy. Methods: 29 consecutive patients with LVEF ⬍45% were consented to undergo DSE. Dobutamine was started at 5 mcg/kg/min, with dose increasing every 3 minutes up to 40 mcg/kg/min or when 85% of maximal predicted heart rate was achieved. A BNP level was at baseline and at peak dobutamine. All DSE studies were reviewed and quantitated by a single observer. LVEF is calculated by Method of Discs. Results: The patients are stratified into 4 groups: 1) Baseline BNP ⬎100pg/ml and increased BNP post DSE 2) Baseline BNP ⬎100pg/ml and decreased BNP post DSE 3) Baseline BNP ⬍ 100pg/ ml and increased BNP post DSE 4) Baseline BNP ⬍ 100pg/ml and decreased BNP post DSE. The correlation between BNP and contractile reserve are listed in Table 1. In general, patients in Group 1 did not have a significant contractile response with DSE whereas patients in Group 2 had a significant increase in LVEF with DSE. Most patients in Group 3 did not have a significant improvement in LVEF but 2 patients did have significant improvement in LVEF. Patients in Group 4 had a significant improvement in their LVEF. Improvement in LVEF and NYHA after treatment with beta blocker were noted in most patients except Group 1 patients. Conclusion: In assessing myocardial contractile reserve, the decrease in BNP levels after DSE, is correlated with the presence of viability. There is a trend that the greater the decrease in BNP, the greater the contractile reserve is seen with DSE and the greater improvement in LVEF on therapy. This is the first biochemical marker for viability. BNP therefore can help identify myocardial contractile reserve in conjunction to the DSE results, and maybe especially helpful in the difficult to image patients. Furthermore, in the cancer patients with chemotherapy induced cardiomyopathy, BNP can be used to predict recovery of cardiac function. CORRELATION OF BNP WITH CONTRACTILE RESERVE
1 Parati G, Izzo JL Jr, Gavish B. Respiration and Blood Pressure,in Hypertension Primer, 3rd ed.. (JL Izzo and HR Black, Eds). AHA 2003, pp.117-120.
GROUP GROUP GROUP GROUP
1(N ⫽ 6) 2(N ⫽ 12) 3(N ⫽ 5) 4(N ⫽ 6)
PRE-BNP
POST-BNP
PRE-LVEF
POST-LVEF
286.5+/⫺190.9 490.3+/⫺328.2 47.3+/⫺34.4 32.3+/⫺28.4
427.3+/⫺275.1 367.5+/⫺295.0 78.7+/⫺80.4 23.8+/⫺22.6
32.2+/⫺7.7 35.5+/⫺10.9 34.2+/ 12.6 41.2+/⫺5.0
31.2+/⫺8.2 47.7+/⫺12.0 40.2+/⫺16.0 57.3+/⫺6.7
362
363
Cardiologist Use of ACE Inhibitors Versus Angiotensin Receptor Blocking Agents for Heart Failure Mary N. Walsh,1 Cynthia D. Adams1—1CardiAction, The Care Group, LLC, Indianapolis, IN
Use of Implanted CRT Device Diagnostics to Determine the Risk of Heart Failure Decompensation William T. Abraham,1 Andrew L. Smith,2 Angel R. Leon,2 Karen J. Kleckner,3 Melissa M. Rhodes3—1Division of Cardiology, The Ohio State University, Columbus, OH; 2 Emory Univ. School of Medicine, Atlanta, GA; 3Medtronic, Inc., Minneapolis, MN
Background: The mortality and morbidity benefits associated with the use of angiotensin converting enzyme inhibitors (ACE) in heart failure (HF) are well established. However, 10-20% of patients given ACE are intolerant due to cough. Angiotensin II receptor blocking agents (ARB) have been promoted as better tolerated alternatives to ACE due to the absence of cough as a side effect. Because of this, prescribing practices may be swayed toward ARB use in spite of the overwhelming data supporting use of ACE for first-line HF treatment. The current American College of Cardiology/American Heart Association Guidelines for the Evaluation and Management of Chronic Heart Failure in the Adult states that ARB should not be considered as equivalent to ACE, and should not be used without prior trial of ACE or substituted for ACE in pts who are tolerating therapy without difficulty. Purpose: The purpose of this study was to examine the prescribing practices, as pertaining to the use of ACE and ARB for HF, among individual cardiologists in a large, single specialty, private practice. Methods: The electronic medical record (EMR) system at a large urban cardiology practice was queried to report the use of ACE and ARB in patients (pts) with diagnoses of HF or cardiomyopathy. The ability of the EMR to select pts by diagnosis, sort by physician, and identify medications prescribed and/or dosage changes made at specific visits, enabled examination of variability of prescribing practices. Pts in whom the specific provider could not be identified, and pts of providers having fewer than 10 pts in the sample were excluded from analysis. Results: 1956 pts with appropriate diagnoses were examined. Of these, 75% were on either an ACE or ARB agent (ACE/ARB). Among subspecialists (HF cardiologists, electrophysiologists, interventional, invasive, and non-invasive cardiologists), HF cardiologists demonstrated the highest ACE/ARB use (83.3%), followed by electrophysiologists (72.3%), non-invasive and interventional cardiologists (both at 71.4%), and invasive cardiologists (65.2%). Among pts on these agents, 80% were on ACE, and 20% were on ARB. ACE use by individual cardiologists ranged from 65% to 97%, and ARB use from 3% to 35%. ARB use did not vary between non-HF cardiologists seeing higher versus lower volumes of HF pts. However, when compared by subspecialty, non-invasive cardiologists tended to be the highest users of ARB (26.9%) followed by interventionalists (21.0%), invasive cardiologists (17.6%), and electrophysiologists (17.1%). The lowest ARB prescribers were the HF specialists (16.8%). Conclusion: The percentage of HF pts receiving therapy with either ACE or ARB was lower than may be expected, at only 75% of the study sample. However, practice patterns in this group reflect an appropriate preference for ACE over ARB in the treatment of HF, with the expected 20% of pts being prescribed ARB. There was wide variability among individual cardiologists in various subspecialties. HF specialists tended to be higher prescribers of ACE/ARB therapy overall, but chose ARB over ACE less frequently than cardiologists in other subspecialties.
Background: Newer implantable cardiac resynchronization therapy (CRT) devices are able to measure and record average night heart rate, heart rate variability and patient activity on a daily basis. The purpose of this retrospective analysis was to assess whether these device measures may be useful for managing patients with heart failure. Methods: We reviewed heart failure decompensation events which included heart failure hospitalizations in a study of CRT for NYHA III/IV heart failure pts without traditional pacing indications (U.S. InSync III trial). Device based heart failure diagnostics were not used to make clinical decisions. Two analyses were performed: 1) the average daily values from one month post implant to the six month follow-up for average night heart rate, heart rate variability and physical activity were compared for pts with and without heart failure decompensation and 2) the ability of night heart rate, heart rate variability and physical actvity to predict heart failure hospitalization was assessed by comparing the weekly average of weeks starting 1 week and 4 weeks prior to the heart failure hospitalization for patients with a hospitalization at least 40 days post implant. Results: Of the 255 patients for whom device data were available, 65 experienced at least one heart failure decompensation. There were 33 patients with a heart failure hospitalization at least 40 days post implant. There were no statistical differences in the following baseline characteristics between the Heart Failure Decompensation and No Heart Failure Decompensation groups (age, gender, etiology, NYHA, LVEF, LVEDD, beta blocker usage), while the No Heart Failure Decompensation group had a slightly wider QRS (167 ms vs. 160 ms, p ⫽ 0.02). As shown in the table, patients with Heart Failure Decompensation have higher average night heart rate, lower heart rate variability and less physical actvity, as measured by the device on a daily basis. Modest, but statistically significant, changes in heart rate variability and physical activity occur a week prior to hospitalization.
Diagnostic Night Heart Rate (bpm) Heart Rate Variability (ms) Physical Activity (hr)
No Heart Failure Decompensation
Heart Failure Decompensation
P-value
Heart Failure Hospitalization -4 Weeks
Heart Failure Hospitalization -1 Week
69.8 ⫾ 9.3
75.2 ⫾ 9.9
P-value
0.0001
78.3 ⫾ 11.4
79.8 ⫾ 12.4
87.6 ⫾ 24.2
0.15
75.4 ⫾ 23.2
0.0008
66.5 ⫾ 21.1
60.6 ⫾ 24.4
0.03
3.1 ⫾ 1.5
2.4 ⫾ 1.2
0.0003
2.6 ⫾ 1.2
2.1 ⫾ 1.1
0.005
Conclusions: CRT devices with these diagnostic capabilities may offer objective measures to help determine which patients warrant closer supervision of their heart failure status.