Changes in heart rate variability, quality of life, and activity in cardiac resynchronization therapy patients: results of the HF-HRV registry

Cardiac Magnetic Resonance, Electromechanical Activation, Kidney Function, and Natriuretic Peptides in Cardiac Resynchronization Therapy Upgrades

As the mechanism for worse prognosis after cardiac resynchronization therapy (CRT) upgrades in heart failure patients with RVP dependence (RVP-HF) has clinical implications for patient selection and CRT implementation approaches, this study's objective was to evaluate prognostic implications of cardiac magnetic resonance (CMR) findings and clinical factors in 102 HF patients (23.5% female, median age 66.5 years old, median follow-up 4.8 years) with and without RVP dependence undergoing upgrade and de novo CRT implants. Compared with other CRT groups, RVP-HF patients had decreased survival (p = 0.02), more anterior late-activated LV pacing sites (p = 0.002) by CMR, more atrial fibrillation (p = 0.0006), and higher creatinine (0.002). CMR activation timing at the LV pacing site predicted post-CRT LV functional improvement (p < 0.05), and mechanical activation onset < 34 ms by CMR at the LVP site was associated with decreased post-CRT survival in a model with higher pre-CRT creatinine and B-type natriuretic peptide (AUC 0.89; p < 0.0001); however, only the higher pre-CRT creatinine partially mediated (37%) the decreased survival in RVP-HF patients. In conclusion, RVP-HF had a distinct CMR phenotype, which has important implications for the selection of LV pacing sites in CRT upgrades, and only chronic kidney disease mediated the decreased survival after CRT in RVP-HF.

Developments in Exercise Capacity Assessment in Heart Failure Clinical Trials and the Rationale for the Design of METEORIC-HF

Heart failure with reduced ejection fraction (HFrEF) is a highly morbid condition for which exercise intolerance is a major manifestation. However, methods to assess exercise capacity in HFrEF vary widely in clinical practice and in trials. We describe advances in exercise capacity assessment in HFrEF and a comparative analysis of how various therapies available for HFrEF impact exercise capacity. Current guideline-directed medical therapy has indirect effects on cardiac performance with minimal impact on measured functional capacity. Omecamtiv mecarbil is a novel selective cardiac myosin activator that directly increases cardiac contractility and in a phase 3 cardiovascular outcomes study significantly reduced the primary composite end point of time to first heart failure event or cardiovascular death in patients with HFrEF. The objective of the METEORIC-HF trial (Multicenter Exercise Tolerance Evaluation of Omecamtiv Mecarbil Related to Increased Contractility in Heart Failure) is to assess the effect of omecamtiv mecarbil versus placebo on multiple components of functional capacity in HFrEF. The primary end point is to test the effect of omecamtiv mecarbil compared with placebo on peak oxygen uptake as measured by cardiopulmonary exercise testing after 20 weeks of treatment. METEORIC-HF will provide state-of-the-art assessment of functional capacity by measuring ventilatory efficiency, circulatory power, ventilatory anaerobic threshold, oxygen uptake recovery kinetics, daily activity, and quality-of-life assessment. Thus, the METEORIC-HF trial will evaluate the potential impact of increased myocardial contractility with omecamtiv mecarbil on multiple important measures of functional capacity in ambulatory patients with symptomatic HFrEF. Registration: URL: https://clinicaltrials.gov; Unique identifier: NCT03759392.

Quality of life measured with EuroQol-five dimensions questionnaire predicts long-term mortality, response, and reverse remodelling in cardiac resynchronization therapy patients

Aims

There are previous studies on quality of life (QoL) in cardiac resynchronization therapy (CRT) patients; however, there are no data with the short EuroQol-five dimensions (EQ-5D) questionnaire predicting outcomes. We aimed to assess the predictive role of baseline QoL and QoL change at 6 months after CRT with EQ-5D on 5-year mortality and response.

Methods and results

In our prospective follow-up study, 130 heart failure (HF) patients undergoing CRT were enrolled. Clinical evaluation, echocardiography, and EQ-5D were performed at baseline and at 6 months of follow–up, continued to 5 years. Primary endpoint was all-cause mortality at 5 years. Secondary endpoints were (i) clinical response with at least one class improvement in New York Heart Association without HF hospitalization and (ii) reverse remodelling with 15% reduction in left ventricular end-systolic volume at 6 months. Fifty-four (41.5%) patients died during 5 years, 85 (65.3%) clinical responders were identified, and 63 patients (48.5%) had reverse remodelling. Baseline issues with mobility were associated with lower response [odds ratio (OR) 0.36, 95% confidence interval (CI) 0.16–0.84; P = 0.018]. Lack of reverse remodelling correlated with self-care issues at baseline (OR 0.10, 95% CI 0.01–0.94; P = 0.04). Furthermore, self-care difficulties [hazard ratio (HR) 2.39, 95% CI 1.17–4.86; P = 0.01) or more anxiety (HR 1.51, 95% CI 1.00–2.26; P = 0.04) predicted worse long-term survival. At 6 months, mobility (HR 3.95, 95% CI 1.89–8.20; P < 0.001), self-care (HR 7.69, 95% CI 2.23–25.9; P = 0.001), or ≥ 10% visual analogue scale (VAS) (HR 2.24, 95% CI 1.27–3.94; P = 0.005) improvement anticipated better survival at 5 years.

Conclusion

EuroQol-five dimension is a simple method assessing QoL in CRT population. Mobility issues at baseline are associated with lower clinical response, whereas self-care issues predict lack of reverse remodelling. Problems with mobility or anxiety before CRT and persistent issues with mobility, self-care, and VAS scale at 6 months predict adverse outcome.

"Doubtful accepting": A grounded theory study of living with cardiac resynchronization therapy

Heart failure is associated with low quality of life and a high mortality rate. There is limited information about patients' experiences of living with cardiac resynchronization therapy (CRT). In the present study, we sought to explore the process of living with CRT defibrillator. This qualitative study was completed from December 2014 to April 2016 using a grounded theory approach. Twenty semistructured interviews were held with 17 patients with heart failure. Data analysis was done via a previously-published approach. The core category of the process of living with the device is "doubtful accepting". This process includes three sequential phases: losing integrity, attempting to cope with the device, and coexisting. The process takes place in a context of barriers and facilitators, and results in a wide spectrum of outcomes, from frustration to empowerment. Nurses' awareness of this process can help them provide higher quality care, strengthen facilitators and reduce barriers to the process, and enable patients to effectively use coping strategies.

Patterns of physical activity and survival following cardiac resynchronization therapy implantation: the ALTITUDE activity study

Aims

Cardiac resynchronization therapy with implantable defibrillator backup (CRT-D) improves outcomes, but predictors and markers of response remain limited. Physical activity information collected by CRT devices may provide insights to CRT response and the relationship between activity changes and survival.

Methods and results

Patients entered into the LATITUDE remote monitoring system from 2008 to 2012 after receipt of a new CRT-D were eligible. Mean daily activity was calculated from LATITUDE uploads at baseline (first 3-10 days following implant) and 6 months (180-210 days). Pairwise differences for baseline-6-month activity were calculated, and survival according to quintiles of 6-month activity change was assessed. Cox regression was used to examine the adjusted association between survival and baseline-6-month activity change. A total of 26 509 patients were followed for a median of 2.3 years (mean age 70.2 ± 11.0 years, 70.7% male). Mean baseline activity was 66.2 ± 47.7 min/day, with mean paired increase at 6 months of 37.1 ± 48.2 min/day [95% CI (confidence interval), 36.5-37.6, P < 0.0001], though 15.5% of patients did not improve or worsened at 6 months. Survival at 3 years was significantly higher in the largest baseline-6-month activity change quintile vs. the lowest quintile (88.9% vs. 62.1%, log-rank P-value < 0.001). Adjusted for age and gender, higher 6-month activity change was associated with a lower risk of death (adjusted hazard ratios 0.65 per 30 min increase in activity, 95% CI, 0.63-0.67).

Conclusions

Change in physical activity between baseline and 6 months following CRT implantation is strongly associated with survival.

Measuring Physical Activity With Implanted Cardiac Devices: A Systematic Review

Background

Physical activity is predictive of cardiovascular outcomes in patients with cardiovascular implantable electronic devices, yet it is not regularly assessed in routine care. Current‐generation cardiovascular implantable electronic devices, however, continuously monitor patient activity through a built‐in accelerometer, which provides new opportunities to remotely assess patient activity, detect changes in clinical status, and incorporate these data in risk stratification models. This review critically examines the literature on device‐measured physical activity (D‐PA), with a focus on identifying methodological issues that may affect interpretation of study results.

Methods and Results

We conducted a systematic review of D‐PA studies published from January 1 1995 to December 30 2017, identifying 29 studies meeting inclusion criteria, 5 of which were validation reports. Few technical details about D‐PA sensors are reported, and procedures for analyzing and interpreting D‐PA data are heterogeneous. Trends in D‐PA over time and associations with clinical outcomes were reported by 22 studies, and in 7 studies, D‐PA was combined with other device parameters in risk stratification models, demonstrating modest‐to‐good sensitivity in predicting acute heart failure decompensation, hospitalization, and mortality.

Conclusions

Current evidence suggests that D‐PA may be useful for assessing physical activity and predicting clinical outcomes in patients with cardiovascular implantable electronic devices when combined with other device parameters. Future work must address challenges related to D‐PA data measurement, interpretation, and generalizability to support expanded clinical applications of this technology.

Left Ventricular Assist Improves Autonomic Imbalance in Patients with Persistent Myocardial Dysfunction

Background

Left ventricular assist devices (LVAD) are an effective therapeutic option for end-stage heart failure (HF). Reduced heart rate variability (HRV) as a result of autonomic derangement is evident in chronic heart failure and several studies have established the independent prognostic value of HRV in chronic heart failure.

Objective

In the present study we investigated whether autonomic function is restored in patients after LVAD implantation with persistent, severely depressed left ventricular function.

Methods

Ambulatory Holter ECG recordings were collected in heart failure patients with an LVAD (n=8) und age-matched heart failure patients without an LVAD (n=7) both on optimal medical therapy. Cardiac dimensions and function were assessed by echocardiography or angiography.

Results

Analysis for heart rate variability revealed reduced SDNN (67±4ms), SDANN (56±4ms) and triangular index (18±1) in heart failure patients on optimal medical therapy. However patients with LVAD demonstrated a restoration in heart rate variability with normal SDNN (108±9ms), SDANN (103±8ms) and triangular index (29±2). Compared to patients without LVAD this difference was statistically significant (p<0.01).

Conclusions

In end-stage heart failure patients autonomic imbalance indicated by severely reduced heart rate variability is restored after LVAD implantation with unloading of the failing heart.

Accelerometer-Measured Daily Activity in Heart Failure With Preserved Ejection Fraction: Clinical Correlates and Association With Standard Heart Failure Severity Indices

BACKGROUND

Daily physical activity assessed by accelerometers represents a novel method to assess the impact of interventions on heart failure (HF) patients' functional status. We hypothesized that daily activity varies by patient characteristics and correlates with established measures of HF severity in HF with preserved ejection fraction.

METHODS AND RESULTS

In this ancillary study of the NEAT-HFpEF trial (Nitrate's Effects on Activity Tolerance in HF With Preserved Ejection Fraction), average daily accelerometer units (ADAU) and hours active per day were assessed during a 14-day period before starting isosorbide mononitrate or placebo (n=110). Baseline ADAU was negatively associated with age, female sex, height, and body mass index, and these variables accounted for 28% of the variability in ADAU (P<0.007 for all). Adjusting for these factors, patients with lower ADAU were more likely to have had an HF hospitalization, orthopnea, diabetes mellitus and anemia, be treated with β-blockers, have higher ejection fraction, relative wall thickness and left atrial volume, and worse New York Heart Association class, HF-specific quality of life scores, 6-minute walk distance, and NT-proBNP (N-terminal pro-B-type natriuretic peptide; P<0.05 for all). Associations between hours active per day and clinical characteristics were similar. Relative to baseline, there were no significant associations between changes in ADAU or hours active per day and changes in standard functional assessments (New York Heart Association, quality of life, 6-minute walk distance, and NT-proBNP) with isosorbide mononitrate.

CONCLUSIONS

Daily activity is a measure of HF-related and global functional status in HF with preserved ejection fraction. As compared with intermittently assessed standard HF assessments, change in daily activity may provide unique information about the impact of HF interventions on functional status.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov/. Unique identifier: NCT02053493.

The future of telemedicine for the management of heart failure patients: a Consensus Document of the Italian Association of Hospital Cardiologists (A.N.M.C.O), the Italian Society of Cardiology (S.I.C.) and the Italian Society for Telemedicine and eHealth (Digital S.I.T.)

Telemedicine applied to heart failure patients is a tool for recording and providing remote transmission, storage and interpretation of cardiovascular parameters and/or useful diagnostic images to allow for intensive home monitoring of patients with advanced heart failure, or during the vulnerable post-acute phase, to improve patient's prognosis and quality of life. Recently, several meta-analyses have shown that telemedicine-supported care pathways are not only effective but also economically advantageous. Benefits seem to be substantial, with a 30-35% reduction in mortality and 15-20% decrease in hospitalizations. Patients implanted with cardiac devices can also benefit from an integrated remote clinical management since all modern devices can transmit technical and diagnostic data. However, telemedicine may provide benefits to heart failure patients only as part of a shared and integrated multi-disciplinary and multi-professional 'chronic care model'. Moreover, the future development of remote telemonitoring programs in Italy will require the primary use of products certified as medical devices, validated organizational solutions as well as legislative and administrative adoption of new care methods and the widespread growth of clinical care competence to remotely manage the complexity of chronicity. Through this consensus document, Italian Cardiology reaffirms its willingness to contribute promoting a new phase of qualitative assessment, standardization of processes and testing of telemedicine-based care models in heart failure. By recognizing the relevance of telemedicine for the care of non-hospitalized patients with heart failure, its strategic importance for the design of innovative models of care, and the many challenges and opportunities it raises, ANMCO and SIC through this document report a consensus on the main directions for its widespread and sustainable clinical implementation.

The arterial baroreflex effectiveness index in risk stratification of chronic heart failure patients who are candidates for cardiac resynchronization therapy

INTRODUCTION

Baroreflex function is an independent marker of prognosis in heart failure (HF). However, little is known about its relation to response to cardiac resynchronization therapy (CRT). The aim of this study is to assess arterial baroreflex function in HF patients who are candidates for CRT.

METHODS

The study population consisted of 25 patients with indication for CRT, aged 65±10 years, NYHA functional class ≥III in 52%, QRS width 159±15 ms, left ventricular ejection fraction (LVEF) 29±5%, left ventricular end-systolic volume (LVESV) 150±48 ml, B-type natriuretic peptide (BNP) 357±270 pg/ml, and peak oxygen consumption (peak VO2) 18.4±5.0 ml/kg/min. An orthostatic tilt test was performed to assess the baroreflex effectiveness index (BEI) by the sequence method. This group was compared with 15 age-matched healthy individuals.

RESULTS

HF patients showed a significantly depressed BEI during tilt (31±12% vs. 49±18%, p=0.001). A lower BEI was associated with higher BNP (p=0.038), lower peak VO2 (p=0.048), and higher LVESV (p=0.031). By applying a cut-off value of 25% for BEI, two clusters of patients were identified: lower risk cluster (BEI >25%) QRS 153 ms, LVESV 129 ml, BNP 146 pg/ml, peak VO2 19.0 ml/kg/min; and higher risk cluster (IEB ≤25%) QRS 167 ms, LVESV 189 ml, BNP 590 pg/ml, peak VO2 16.2 ml/kg/min.

CONCLUSIONS

Candidates for CRT show depressed arterial baroreflex function. Lower BEI was observed in high-risk HF patients. Baroreflex function correlated closely with other clinical HF parameters. Therefore, BEI may improve risk stratification in HF patients undergoing CRT.

Heart rate variability reflects the natural history of physiological development in healthy children and is not associated with quality of life

Background

Quality of life (QoL), being the sum expression of diverse influencing factors, is not easy to determine. A clinically relevant option would be to identify and measure quality of life on the basis of physiological parameters which correlate plausibly and statistically with psychometrically measured QoL. Analysis of heart rate variability (HRV) offers readily measurable physiological parameters which could be of use here. A correlation of HRV with both course of disease and QoL has been reported in patients with chronic illness. Various psychometric instruments have been developed for use in paediatric oncology. The aim of this study was to obtain data on HRV and QoL and their correlations, initially in healthy children.

Methods

Holter ECG and quality of life were examined in 160 children and adolescents (72 male) aged between 8 and 18 years. QoL was determined with the established questionnaire PEDQoL. Standard parameters of HRV from the frequency domain were calculated and correlated with QoL domains using Spearman (nonparametric) correlation analysis.

Results

Minor but significant associations were revealed only with regard to the PEDQoL domain “autonomy” on the one hand and heart rate and HRV (e.g. MRR, MRRn, MRRd, HRV_ULF, SDNN) parameters which evidently reflect distinct physiological functions on the other.

Conclusions

In healthy children and adolescents we have a first indication that there is a correlation between parameters of HRV and QoL. However, to a greater extent, HRV reflects associated physiological processes of the autonomic nervous system. A higher correlation is more likely to be found in chronically ill children.

Association of Psychosocial Factors and Heart Rate Variability in Heart Failure Patients

The purpose of this study was to examine the association of psychosocial factors (depression, social support, and health-related quality of life) with heart rate variability (HRV) in patients with heart failure. The sample comprised 91 outpatients from a medical center. Data were collected using the Beck Depression Inventory-II, Medical Outcomes Study (MOS) Social Support Survey, and Minnesota Living With Heart Failure Questionnaire. HRV was measured in terms of time-domain parameters from a 24-hr ambulatory Holter electrocardiogram. After adjusting for demographic and clinical variables, quality of life and social support were significantly associated with HRV. HRV (time-domain measures) was significantly higher in patients who perceived better quality of life and more social support. Our findings suggest that nurses could screen early for patients' risk of adverse psychosocial conditions and suggest online or other social supportive interventions to help at-risk patients minimize the negative associations with HRV.

Improvement of heart rate variability by eurythmy therapy after a 6-week eurythmy therapy training

BACKGROUND

Eurythmy therapy (EYT) is a mind-body therapy used in anthroposophic medicine. Recently, the authors were able to show that at comparable workloads, EYT stimulated heart rate variability (HRV) whereas conventional ergometer training attenuated HRV. Furthermore, a long-term improvement of quality of life (QoL) and stress coping strategies by EYT could be shown.

OBJECTIVE

This study aimed to evaluate the long-term effects of EYT training on HRV.

DESIGN

A total of 23 healthy women (mean age = 44.57 ± 8.04 years) performed 10 hours of EYT over a period of 6 weeks. Electrocardiograms were recorded before and after the EYT trial. HRV was quantified by the extent of high (HF), low (LF), very low (VLF), and ultra low frequency (ULF) oscillations of heart rate.

RESULTS

Autonomic regulation was significantly changed following the EYT training compared with baseline. Especially the proportion referring to the total power (P) of HF/P and LF/P increased, whereas ULF/P and (ULF+VLF)/P decreased after the training period.

CONCLUSION

EYT shifted the autonomic regulation proportionally referring to the total power mainly caused by changes of ULF and VLF components of HRV. The LF and HF spectral components were also decreased following EYT while their proportion in relation to the total variance of the power spectrum was increased. The proportional enhancement of the higher frequency and the decrease of the ULF and VLF components are probably an indicator of an improvement of autonomic regulation processes by more relaxed physical activity after the EYT training, thus supporting the plausibility of the improved QoL and better stress coping strategies.

Baseline heart rate variability predicts clinical events in heart failure patients implanted with cardiac resynchronization therapy: validation by means of related complexity index

BACKGROUND

Studies on the physiology of the cardiovascular system suggest that generation of the heart rate (HR) signal is governed by nonlinear dynamics. Linear and nonlinear indices of HR variability (HRV) have been shown to predict outcome in heart failure (HF). Aim of the present study is to assess if a HR-related complexity predicts adverse clinical and cardiovascular events at 1 year in patients implanted with cardiac resynchronization therapy (CRT).

METHODS

In sixty patients implanted with CRT (Renewal), 24-hour HR data were retrieved at patient discharge and 1-year follow-up. A set of linear indices of HRV were considered: mean HR, standard deviation of normal beat to normal beat (SDANN), and HR footprint. Two novel nonlinear indices were calculated by means of a specific algorithm (OntoSpace): HR-complexity (HR-Co) and HR-entropy (HR-En). Predictors of adverse clinical outcome (functional class deterioration or major hospitalizations for cardiovascular causes or all-cause mortality) and of HRV recovery were sought by means of multivariate analysis.

RESULTS

HR-Co and HR-En were found to be highly correlated with the other traditional indices of HRV. Lower baseline values of COMPLEXITY WERE ASSOCIATED WITH ADVERSE CLINICAL OUTCOMES (HAZARD RATIO [HR] 0.71; 95% CONFIDENCE INTERVAL [CI] 0.54-0.95; P < 0.02).

CONCLUSION

Complexity and entropy indices, calculated from 24-hour normal beat to normal beat (RR) intervals well represent patient's autonomic function. In this limited set of data, HF patients with lower baseline complexity-related indices, representing a more compromised autonomic function, present worse clinical outcome at 1-year follow-up.

Magnesium administration may improve heart rate variability in patients with heart failure

BACKGROUND AND AIM

Intracellular magnesium (icMg) depletion may coexist with normomagnesemia. Mg deficiency (serum and/or intracellular) and decreased heart rate variability (HRV) are common in heart failure (HF). Since both are predictors of poor prognosis, it was of interest to evaluate the effect of Mg supplementation on HRV in patients with HF.

METHODS AND RESULTS

We investigated the effect of Mg administration on HRV in normomagnesemic patients with systolic HF. HRV, serum Mg and icMg were determined before and after 5-week 300 mg/day Mg citrate treatment in 16 patients (group 1). The control group included 16 Mg-non-treated HF patients (group 2). HRV was determined by a non-linear dynamics analysis, derived from the chaos theory, which calculates HRV-correlation dimension (HRV-CD). After 5 weeks, serum Mg (mmol/l) increased more significantly in group 1 (from 0.78+/-0.04 to 0.89+/-0.06, p<0.001), than in group 2 (from 0.79+/-0.07 to 0.84+/-0.06, p=0.042). IcMg and HRV-CD increased significantly only in group 1 (from 59+/-7 to 66+/-9 mmol/g cell protein, p=0.025, and from 3.47+/-0.42 to 3.94+/-0.36, p<0.001, respectively). In group 2, the differences in the respective parameters were 63+/-12 to 66+/-9 mmol/g cell protein (p=0.7) and 3.59+/-0.42 to 3.55+/-0.4 (p=0.8).

CONCLUSION

Mg administration to normomagnesemic patients with systolic HF increases serum Mg, icMg and HRV-CD. Increasing of HRV by Mg supplementation may prove beneficial to HF patients.

Relationship between exercise capacity and heart rate variability: supine and in response to an orthostatic stressor

The study investigated whether supine-measured HRV indicators, and/or HRV indicators measured during orthostatic stress are related to conventional measures of exercise and performance ability such as VO(2max). Only two significant correlations (p<0.05) out of 30 tests were found between supine-determined HRV indicators and conventional measures. In contrast, fifteen of the 30 relationships calculated during orthostatic stress were significant. Relationships were at best low to moderate (0.2<|corr|<0.4). As expected, the relationships obtained during orthostatic stress were reversed from that obtained in the supine position. In summary, although HRV indicators are related to cardiovascular fitness, correlations between VO(2max) and these parameters are found only under very specific conditions. HRV parameters explain very little of the variance in VO(2max). In addition, estimating the exercise capacity from HRV indicators requires experience and extreme caution.

Device diagnostics and long-term clinical outcome in patients receiving cardiac resynchronization therapy

AIMS

This retrospective analysis sought to develop and validate a model using the measured diagnostic variables in cardiac resynchronization therapy (CRT) devices to predict mortality.

METHODS AND RESULTS

Data used in this analysis came from two CRT studies: Cardiac Resynchronization Therapy Registry Evaluating Patient Response with RENEWAL Family Devices (CRT RENEWAL) (n = 436) and Heart Failure-Heart Rate Variability (HF-HRV) (n = 838). Patients from CRT RENEWAL were used to create a model for risk of death using logistic regression and to create a scoring system that could be used to predict mortality. Results of both the logistic regression and the clinical risk score were validated in a cohort of patients from the HF-HRV study. Diagnostics significantly improved over time post-CRT implant (all P < 0.001) and were correlated with a trend of decreased risk of death. The regression model classified CRT RENEWAL patients into low (2.8%), moderate (6.9%), and high (13.8%) risk of death based on tertiles of their model predicted risk. The clinical risk score classified CRT RENEWAL patients into low (2.8%), moderate (10.1%), and high (13.4%) risk of death based on tertiles of their score. When both the regression model and the clinical risk score were applied to the HF-HRV study, each was able to classify patients into appropriate levels of risk.

CONCLUSION

Device diagnostics may be used to create models that predict the risk of death.

Using devices for physiologic monitoring in heart failure

Heart failure (HF) is a complex and costly disease process associated with high morbidity and mortality. Implanted cardiac rhythm management devices are increasingly used in the HF population to provide therapies such as protection from sudden death and cardiac resynchronization therapy. Device-based diagnostic monitoring provides clinicians with information that can assist in identifying patients at risk for HF decompensation and subsequent hospitalization. This article will review the evidence for using diagnostic information from cardiac rhythm management devices in the management of HF patients. Future advanced monitoring devices will also be discussed.