title: Randomized trial of a daily electronic home monitoring system in patients with advanced heart failure: the Weight Monitoring in Heart Failure (WHARF) trial. Intrathoracic Impedance Monitoring, Audible Patient Alerts, and Outcome in Patients With Heart Failure Clinical utility of intrathoracic impedance monitoring to alert patients with an implanted device of deteriorating chronic heart failure. Device monitoring strategies in acute heart failure syndromes Noninvasive home telemonitoring for patients with heart failure at high risk of recurrent admission and death: the Trans-European Network-Home-Care Management System (TEN-HMS) study. A multicenter randomized controlled evaluation of automated home monitoring and telephonic disease management in patients recently hospitalized for congestive heart failure: the SPAN-CHF II trial. Randomized trial of a nurse-administered, telephone-based disease management program for patients with heart failure. Cardiac-resynchronization therapy for the prevention of heart-failure events. Remote monitoring of patients with biventricular defibrillators through the CareLink system improves clinical management of arrhythmias and heart failure episodes Insights from internet-based remote intrathoracic impedance monitoring as part of a heart failure disease management program. Efficacy of fluid assessment based on intrathoracic impedance monitoring in patients with systolic heart failure. Implantable CRT device diagnostics identify patients with increased risk for heart failure hospitalization The CONNECT (Clinical Evaluation of Remote Notification to Reduce Time to Clinical Decision) trial: the value of wireless remote monitoring with automatic clinician alerts. Integration of automatic intrathoracic fluid content measurement into clinical decision making in patients with congestive heart failure. Impact of Telehealth on Clinical Outcomes in Patients With Heart Failure Monitoring intrathoracic impedance with an implantable defibrillator reduces hospitalizations in patients with heart failure. Sensitivity and positive predictive value of implantable intrathoracic impedance monitoring as a predictor of heart failure hospitalizations: the SENSE-HF trial. Combined heart failure device diagnostics identify patients at higher risk of subsequent heart failure hospitalizations: results from PARTNERS HF (Program to Access and Review Trending Information and Evaluate Correlation to Symptoms in Patients With Heart Failure) study. Intrathoracic impedance vs daily weight monitoring for predicting worsening heart failure events: results of the Fluid Accumulation Status Trial (FAST).
abstract: BACKGROUND Heart failure treatment guidelines emphasize daily weight monitoring for patients with heart failure , but data to support this practice are lacking . Using a technology-based heart failure monitoring system , we determined whether daily reporting of weight and symptoms in patients with advanced heart failure would reduce rehospitalization and mortality rates despite aggressive guideline -driven heart failure care . METHODS This was a r and omized , controlled trial . Patients hospitalized with New York Heart Association class III or IV heart failure , with a left ventricular ejection fraction < or = 35 % were r and omized to receive heart failure program care or heart failure program care plus the AlereNet system ( Alere Medical , Reno , Nev ) and followed-up for 6 months . The primary end point was 6-month hospital readmission rate . Secondary end points included mortality , heart failure hospitalization readmission rate , emergency room visitation rate , and quality of life . RESULTS Two hundred eighty patients from 16 heart failure centers across the United States were r and omized : 138 received the  AlereNet system and 142 received st and ard care .  Mean age was 59 + /- 15 years and 68 % were male . The population had very advanced heart failure , New York Heart Association class III ( 75 % ) or IV ( 25 % ) , as evidence d by serum norepinepherine levels , 6-minute walk distance and outcomes .  No differences in hospitalization rates were observed . There was a 56.2 % reduction in mortality ( P < .003 ) for patients r and omized to the AlereNet group . CONCLUSIONS This is the largest multicenter , r and omized trial of a technology-based daily weight and symptom-monitoring system for patients with advanced heart failure . Despite no difference in the primary end point of rehospitalization rates , mortality was significantly reduced for patients r and omized to the AlereNet system without an increase in utilization , despite specialized and aggressive heart failure care in both groups Background — Heart failure is associated with frequent hospitalizations , often result ing from volume overload . Measurement of intrathoracic impedance with an implanted device with an audible patient alert may detect increases in pulmonary fluid retention early . We hypothesized that early intervention could prevent hospitalizations and affect outcome . Methods and Results — We studied 335 patients with chronic heart failure who had undergone implantation of an implantable cardioverter-defibrillator alone ( 18 % ) or with cardiac resynchronization therapy ( 82 % ) . All devices featured a monitoring tool to track changes in intrathoracic impedance ( OptiVol ) and other diagnostic parameters . Patients were r and omized to have information available to physicians and patients as an audible alert in case of preset threshold crossings ( access arm ) or not ( control arm ) . The primary end point was a composite of all-cause mortality and heart failure hospitalizations . During 14.9±5.4 months , this occurred in 48 patients ( 29 % ) in the access arm and in 33 patients ( 20 % ) in the control arm ( P=0.063 ; hazard ratio , 1.52 ; 95 % confidence interval , 0.97–2.37 ) . This was due mainly to more heart failure hospitalizations ( hazard ratio , 1.79 ; 95 % confidence interval , 1.08–2.95 ; P=0.022 ) , whereas the number of deaths was comparable ( 19 versus 15 ; P=0.54 ) . The number of outpatient visits was higher in the access arm ( 250 versus 84 ; P<0.0001 ) , with relatively more signs of heart failure among control patients during outpatient visits . Although the trial was terminated as a result of slow enrollment , a post hoc futility analysis indicated that a positive result would have been unlikely . Conclusion — Use of an implantable diagnostic tool to measure intrathoracic impedance with an audible patient alert did not improve outcome and increased heart failure hospitalizations and outpatient visits in heart failure patients . Clinical Trial Registration — URL : http://www . clinical trials.gov . Unique identifier : NCT 00480077 AIMS To evaluate the utility of intrathoracic impedance monitoring for detecting  heart failure ( HF ) deterioration in patients with an implanted cardiac resynchronization/defibrillation device . METHODS AND RESULTS Patients enrolled in the European InSync Sentry Observational Study were audibly alerted by a device algorithm if a decrease in intrathoracic impedance suggested fluid accumulation . Clinical HF status and device data were assessed at enrolment , during regular follow-up , and if patients presented with an alert or HF deterioration .  Data from 373 subjects were analysed . Fifty-three alert events and a total of 53 clinical events ( HF deterioration defined by worsening of HF signs and symptoms ) were reported during a median of 4.2 months . Adjusted for multiple events per patient , the alert detected clinical HF deterioration with 60 % sensitivity ( 95 % CI 46 - 73 ) and with a positive predictive value of 60 % ( 95 % CI 46 - 73 ) . Higher NYHA class at baseline was predictive for adequate alert events during follow-up ( P < 0.05 ) . In 11 of 20 HF deteriorations without preceding alert , an upstroke of the fluid index occurred without reaching the programmed alert threshold . CONCLUSION A device-based algorithm that alerts patients in case of decreasing intrathoracic impedance facilitates the detection of HF deterioration . Future r and omized , controlled trials are needed to test whether the tailored use of intrathoracic impedance monitoring can improve the ambulatory management of patients with chronic HF and an implanted device Acute heart failure syndromes ( AHFS ) represent the most common discharge diagnoses in adults over age 65 and translate into dramatically increased heart failure – associated morbidity and mortality . Conventional approaches to the early detection of pulmonary and systemic congestion have been shown to be of limited sensitivity . Despite their proven efficacy , disease management and structured telephone support programs have failed to achieve widespread use in part due to their re source intensiveness and reliance upon motivated patients . While once thought to hold great promise , results from recent prospect i ve studies on telemonitoring strategies have proven disappointing . Implantable devices with their capacity to monitor electrophysiologic and hemodynamic parameters over long periods of time and with minimal reliance on patient participation may provide solutions to some of these problems . Conventional electrophysiologic parameters and intrathoracic impedance data are currently available in the growing population of heart failure patients with equipped devices . A variety of implantable hemodynamic monitors are currently under investigation . How best to integrate these devices into a systematic approach to the management of patients before , during , and after AHFS  is yet to be established OBJECTIVES We sought to identify whether home telemonitoring ( HTM ) improves outcomes compared with nurse telephone support ( NTS ) and usual care ( UC ) for patients with heart failure who are at high risk of hospitalization or death . BACKGROUND Heart failure is associated with a high rate of hospitalization and poor prognosis . Telemonitoring could help implement and maintain effective therapy and detect worsening heart failure and its cause promptly to prevent medical crises . METHODS Patients with a recent admission for heart failure and left ventricular ejection fraction ( LVEF ) < 40 % were assigned r and omly to HTM , NTS , or UC in a 2:2:1 ratio . HTM consisted of twice-daily patient self-measurement of weight , blood pressure , heart rate , and rhythm with automated devices linked to a cardiology center . The NTS consisted of specialist nurses who were available to patients by telephone . Primary care physicians delivered UC . The primary end point was days dead or hospitalized with NTS versus HTM at 240 days . RESULTS Of 426 patients r and omly assigned , 48 % were aged > 70 years , mean LVEF was 25 % ( SD , 8) and median plasma N-terminal pro-brain natriuretic peptide was 3,070 pg/ml ( interquartile range 1,285 to 6,749 pg/ml ) . During 240 days of follow-up , 19.5 % , 15.9 % , and 12.7 % of days were lost as the result of death or hospitalization for UC , NTS , and HTM , respectively ( no significant difference ) . The number of admissions and mortality were similar among patients r and omly assigned to NTS or HTM , but the mean duration of admissions was reduced by 6 days ( 95 % confidence interval 1 to 11 ) with HTM . Patients r and omly assigned to receive UC had higher one-year mortality ( 45 % ) than patients assigned to receive NTS ( 27 % ) or HTM ( 29 % ) ( p = 0.032 ) . CONCLUSIONS Further investigation and refinement of the application of HTM are warranted because it may be a valuable role for the management of selected patients with heart failure BACKGROUND We performed a prospect i ve , r and omized investigation assessing the incremental effect of automated health monitoring ( AHM ) technology over and above that of a previously described nurse directed heart failure ( HF ) disease management program . The AHM system measured and transmitted body weight , blood pressure , and heart rate data as well as subjective patient self- assessment s via a st and ard telephone line to a central server . METHODS AND RESULTS A total of 188 consented and eligible patients were r and omized between intervention and control groups in 1:1 ratio . Subjects r and omized to the control arm received the Specialized Primary and Networked Care in Heart Failure ( SPAN-CHF ) heart failure disease management program . Subjects r and omized to the intervention arm received the SPAN-CHF disease management program in conjunction with the AHM system . The primary end point was prespecified as the relative event rate of HF hospitalization between intervention and control groups at 90 days . The relative event rate of HF hospitalization for the intervention group compared with controls was 0.50 ( 95%CI [ 0.25 - 0.99 ] , P = .05 ) . CONCLUSIONS Short-term reductions in the heart failure hospitalization rate were associated with the use of automated home monitoring equipment . Long-term benefits in this model remain to be studied BACKGROUND Heart failure is a common and important cause of morbidity and mortality . Disease management offers promise in reducing the need for hospitalization and improving quality of life for heart failure patients , but experimental data on the efficacy of such programs are limited . METHODS AND RESULTS A total of 151 patients hospitalized with heart failure were r and omized to usual care or scheduled telephone calls by specially trained nurses promoting self-management and guideline -based therapy as prescribed by primary physicians . Nurses also screened patients for heart failure exacerbations , which they managed with supplemental diuretics or by contacting the primary physician for instructions . Outcomes included time to hospital encounter , mortality , number and cost of hospitalizations , functional status , and satisfaction with care . Intervention patients had a longer time to encounter ( hazard ratio [ HR ] = 0.67 ; 95 % confidence interval [ CI ] 0.47 - 0.96 ; P = .029 ) , hospital readmission ( HR = 0.67 ; CI 0.46 - 0.99 ; P = .045 ) , and heart failure-specific readmission ( HR = 0.62 ; CI 0.38 - 1.03 ; P = .063 ) . The number of admissions , hospital days , and hospital costs were significantly lower during the first 6 months after intervention but not at 1 year . The intervention had little effect on functional status , mortality , and satisfaction with care . CONCLUSION A nurse-administered , telephone-based disease management program delayed subsequent health care encounters , but had minimal impact on other outcomes BACKGROUND This trial was design ed to determine whether cardiac-resynchronization therapy ( CRT ) with biventricular pacing would reduce the risk of death or heart-failure events in patients with mild cardiac symptoms , a reduced ejection fraction , and a wide QRS complex . METHODS During a 4.5-year period , we enrolled and followed 1820 patients with ischemic or nonischemic cardiomyopathy , an ejection fraction of 30 % or less , a QRS duration of 130 msec or more , and New York Heart Association class I or II symptoms . Patients were r and omly assigned in a 3:2 ratio to receive CRT plus an implantable cardioverter-defibrillator ( ICD ) ( 1089 patients ) or an ICD alone ( 731 patients ) . The primary end point was death from any cause or a nonfatal heart-failure event ( whichever came first ) . Heart-failure events were diagnosed by physicians who were aware of the treatment assignments , but they were adjudicated by a committee that was unaware of assignments . RESULTS During an average follow-up of 2.4 years , the primary end point occurred in 187 of 1089 patients in the CRT-ICD group ( 17.2 % ) and 185 of 731 patients in the ICD-only group ( 25.3 % ) ( hazard ratio in the CRT-ICD group , 0.66 ; 95 % confidence interval [ CI ] , 0.52 to 0.84 ; P=0.001 ) . The benefit did not differ significantly between patients with ischemic cardiomyopathy and those with nonischemic cardiomyopathy . The superiority of CRT was driven by a 41 % reduction in the risk of heart-failure events , a finding that was evident primarily in a prespecified subgroup of patients with a QRS duration of 150 msec or more . CRT was associated with a significant reduction in left ventricular volumes and improvement in the ejection fraction . There was no significant difference between the two groups in the overall risk of death , with a 3 % annual mortality rate in each treatment group . Serious adverse events were infrequent in the two groups . CONCLUSIONS CRT combined with ICD decreased the risk of heart-failure events in relatively asymptomatic patients with a low ejection fraction and wide QRS complex . ( Clinical Trials.gov number , NCT00180271 . Purpose The aim of the present study is to evaluate if remote monitoring with the CareLink Network may improve clinical management of tachyarrhythmias and heart failure episodes in patients treated with biventricular defibrillators ( CRT-D ) .  Methods Patients implanted with CRT-D for more than 6 months received the CareLink monitor and were trained to perform device interrogation . At-home transmissions were scheduled at 2 weeks , 1 and 2 months after training , with a final in-office visit after 3 months . Results Sixty-seven patients performed 264 data transmissions . Twenty-three unscheduled data transmissions were requested by the centers after patient contact . Ventricular tachyarrhythmias were reported in nine patients during 16 data review s. Thirteen data review s ( 81 % ) were performed remotely via CareLink transmissions ( nine scheduled and four unscheduled ) , in seven patients . Of these events , in two cases ( 15 % ) in-hospital visits were requested , while in 11 ( 85 % ) no action was needed and no additional in-clinic visits were scheduled . During the study period , in 20/28 ( 71 % ) intra-thoracic impedance alerts , the patients remotely transmitted their device data . After remote data review , in ten cases drug therapy was adjusted by phone and in four cases no action was needed and the patient reassured . In six episodes an in-hospital extra visit was scheduled . On the whole , in 14 cases ( 70 % ) , the patient could be managed remotely avoiding a visit to the hospital . Conclusions Our study showed that remote follow-up is an efficient method to manage tachyarrhythmias and heart failure episodes in  CRT-D patients . Early reaction to clinical events may improve overall patient care Changes in intrathoracic impedance ( Z ) leading to crossing of a derived fluid index ( FI ) threshold has been associated with heart failure ( HF ) hospitalization . The authors developed a remote monitoring program as part of HF disease management and prospect ively examined the feasibility and re source utilization of monitoring individuals with an implanted device capable of measuring Z. An HF nurse analyzed all transmitted data daily , as they were routinely uploaded as part of quarterly remote device monitoring , and called the patient if the FI crossed the threshold ( arbitrarily defined at 60 Omega ) to identify clinical ly relevant events ( CREs ) that occurred during this period ( eg , worsening dyspnea or increase in edema or weight ) . A total of 400 uploads were completed during the 4-month study period . During this period , 34 patients ( 18 % ) had an FI threshold crossing , averaging 0.52 FI threshold crossings per patient-year . Thirty-two of 34 patients contacted by telephone ( 94 % ) with FI threshold crossing had evidence of CREs during this period . However , only 6 ( 18 % ) had HF hospitalizations , 19 ( 56 % ) had reported changes in HF therapy , and 13 ( 38 % ) reported drug and /or dietary plan nonadherence . The average data analysis time required was 30 min daily when focusing on those with FI threshold crossing , averaging 8 uploads for review per working day and 5 telephone follow-ups per week . Our pilot observations suggested that Internet-based remote monitoring of Z trends from existing device interrogation uploads is feasible as part of a daily routine of HF disease management BACKGROUND Previous studies have demonstrated that intrathoracic impedance monitoring ( IIM ) is associated with fluid overload . However , it remains unclear whether this new technology can predict heart failure ( HF ) before deterioration . Whether fluid status based on IIM predicts HF in patients with left ventricular ( LV ) systolic dysfunction was investigated . METHODS AND RESULTS A prospect i ve clinical observational study of 123 patients implanted with IIM-capable cardiac devices  was carried out . The primary endpoint was the positive predictive value ( PPV ) at 12 months . Secondary endpoints were a correlation between onset of HF and IIM , optimal threshold of fluid index and duration between the alert and HF . Complete follow-up clinical data were obtained from 111 patients . During the observational period , 168 alerts were confirmed from 68 patients . In patient-based analysis ( alert-based analysis ) , PPV was 33.8 % ( 33.9 % ) . Sensitivity , specificity and false positive was 67.6 % ( 83.8 % ) , 49.4 % ( 28.4 % ) and 50.6 % ( 71.6 % ) , respectively . Mean duration between the alert and HF event was 21.4 ± 6.1 days . On multivariate logistic analysis , maximum fluid index , LV ejection fraction and atrial fibrillation were independent predictors of HF events . The optimal cut-off value determined by receiver operating characteristic curve was 114-ohm·day with sensitivity and specificity of 89.5 % and 73.0 % , respectively . CONCLUSIONS IIM-based fluid index in patients with HF due to LV systolic dysfunction was effective in predicting worsening HF Purpose To determine the association between device-determined diagnostic indices , including intrathoracic impedance , and heart failure ( HF ) hospitalization . Methods Clinical and device diagnostic data of 558 HF patients indicated for CRT-D therapy ( In Sync Sentry , Medtronic Inc. ) were prospect ively collected from 34 centers . Device-recorded intrathoracic impedance fluid index threshold crossing event ( TCE ) , mean activity counts , tachyarrhythmia events , night heart rate ( NHR ) and heart rate variability ( HRV ) were compared within patients with vs. without documented HF hospitalization . Results Mean follow-up was 326 ± 216 days . Patients hospitalized for HF had significantly higher rates of TCE , a higher percentage of days with the thoracic impedance fluid index above the programmed threshold , a higher percentage of days with low activity , with low HRV or with high NHR.Multivariate analysis showed that TCE result ed in a 36 % increased probability of HF hospitalization . Both TCE duration and patient activity were also significantly associated with hospitalization . Kaplan Meier analysis indicated that patients with more TCE events were significantly more likely to be hospitalized ( log rank test , p = 0.005 ) . Conclusions Decreased intrathoracic impedance , low patient activity and low HRV were all independently associated with increased risk for HF hospitalization in HF patients treated with resynchronization therapy . Device-derived diagnostic data may provide valuable and reliable indices for the prognostic stratification of HF patients OBJECTIVES The primary objective was to determine if wireless remote monitoring with automatic clinician alerts reduces the time from a clinical event to a clinical decision in response to arrhythmias , cardiovascular ( CV ) disease progression , and device issues compared to patients receiving st and ard in-office care . A secondary objective was to compare the rates of CV health care utilization between patients in the remote and in-office arms . BACKGROUND In addition to providing life-saving therapy , implantable cardioverter-defibrillators collect advanced diagnostics on the progression of the patient 's heart disease . Device technology has progressed to allow wireless remote monitoring with automatic clinician alerts to replace some scheduled in-office visits . METHODS The CONNECT ( Clinical Evaluation of Remote Notification to Reduce Time to Clinical Decision ) study was a multicenter , prospect i ve , r and omized evaluation involving 1,997 patients from 136 clinical sites who underwent insertion of an implantable cardioverter-defibrillator ( including cardiac resynchronization therapy devices ) and were followed up for 15 months . Health care utilization data included all CV-related hospitalizations , emergency department visits , and clinic office visits . RESULTS The median time from clinical event to clinical decision per patient was reduced from 22 days in the in-office arm to 4.6 days in the remote arm ( p < 0.001 ) . The health care utilization data revealed a decrease in mean length of stay per CV hospitalization visit from 4.0 days in the in-office arm to 3.3 days in the remote arm ( p = 0.002 ) . CONCLUSIONS Wireless remote monitoring with automatic clinician alerts as compared with st and ard in-office follow-up significantly reduced the time to a clinical decision in response to clinical events and was associated with a significant reduction in mean length of CV hospital stay . ( Clinical Evaluation of Remote Notification to Reduce Time to Clinical Decision [ CONNECT ] ; NCT00402246 ) BACKGROUND Hospitalizations due to decompensation are a frequent problem in treating patients with congestive heart failure ( CHF ) .  Continuous impedance measurement via implantable devices may detect pulmonary fluid accumulation due to worsening CHF . An acoustic alert might allow an earlier treatment of impending decompensation . An algorithm that implemented impedance measurement into clinical decision making in treating CHF patients was evaluated . METHODS Forty-two CHF patients ( ejection fraction : 27 + /- 6 % ; New York Heart Association 2.9 + /- 0.6 ) with cardiac resynchronization therapy and automatic impedance measurements were included . Upon an alert , a stepped therapy was initiated : category ( 1 ) overt decompensation , hospitalization ; category ( 2 ) worsened CHF , increase of diuretics ; category ( 3 ) no CHF worsening , brain natriuretic peptide ( BNP ) measurement , elevated BNP : increase of diuretics , normal BNP : no specific treatment . RESULTS During 18 + /- 4 months , 45 alerts were treated according to the algorithm . Eleven category 1 alerts led to hospitalization ; 21 category 2 and 11 category 3 patients ( elevated BNP ) were treated conservatively . Two category 3 alerts ( normal BNP ) received no treatment . CONCLUSIONS Automatic impedance measurement can be integrated into CHF management . BNP measurement restricted to patients with alert but without clinical signs of worsened CHF may prevent premature therapy escalation The purpose of this r and omized field study was to determine the effects of telehomecare on hospitalization , emergency department ( ED ) use , mortality , and symptoms related to sodium and fluid intake , medication use , and physical activity . The sample consists of 284 patients with heart failure . The authors used logistic regression to study the effects of telehomecare on health services utilization and mortality and a general linear model to analyze changes in self-reported symptoms . On average , patients in the telehomecare groups had a lower probability of hospitalizations and ED visits than did patients in the control group . Differences were statistically significant at 60 days but not 120 days . Results show a greater reduction in symptoms for patients using telehomecare compared to control patients . The technology enables frequent monitoring of clinical indices and permits the home health care nurse to detect changes in cardiac status and intervene when necessary PURPOSE Some implantable cardioverter-defibrillators ( ICDs ) are now able to monitor intrathoracic impedance . The aim of the study was to describe the use of such monitoring in clinical practice and to evaluate the clinical impact of the fluid accumulation alert feature of these ICDs . METHODS AND RESULTS Five hundred thirty-two heart failure ( HF ) patients implanted with these ICDs  were followed up for 11 + /- 7 months . A clinical event ( CE ) was deemed to have occurred if it result ed in hospitalization or milder manifestations of HF deterioration . Three hundred sixty-two acute decreases in intrathoracic impedance ( Z events ) occurred in 230 patients . Of these episodes , 171 ( 47 % ) were associated with a CE within 2 weeks of the Z event . In another 71 ( 20 % ) Z events , drug therapy was adjusted despite the absence of overt signs of clinical deterioration . The rate of unexplained Z events was 0.25 per patient-year and 25 hospitalizations were not associated with Z events . The audible alert was disabled in a group of 102 patients ( OFF group ) .  HF hospitalizations occurred in 29 ( 7 % ) patients in the ON group and 20 ( 20 % , P < 0.001 ) patients in the OFF group . The rate of combined cardiac death and HF hospitalization was lower in patients with Alert ON ( log-rank test , P = 0.007 ) . CONCLUSIONS The ICD reliably detected CE and yielded low rates of unexplained and undetected events . The alert capability seemed to reduce the number of HF hospitalizations by allowing timely detection and therapeutic intervention AIMS Early recognition of impending decompensation and timely intervention may prevent heart failure ( HF ) hospitalization . We investigated the performance of OptiVol ® intrathoracic fluid monitoring for the prediction of HF events in chronic HF patients newly implanted with a device ( implantable cardioverter-defibrillator with or without cardiac resynchronization therapy ) . METHODS AND RESULTS SENSE-HF was a prospect i ve , multi-centre study that enrolled 501 patients . Phase I ( double blinded , 6 months ) determined the sensitivity and positive predictive value ( PPV ) of the OptiVol data in predicting HF hospitalizations . Of 58 adjudicated HF hospitalizations that occurred during the first 6 months in Phase I , 12 were predicted by OptiVol ( sensitivity = 20.7 % ) . Sensitivity appeared to be dynamic in nature and at the end of Phase I , had increased to 42.1 % . With 253 OptiVol detections , PPV for Phase I was 4.7 % . Phase II/III ( unblinded , 18 months ) determined the PPV of the first OptiVol Patient Alert for detection of worsening HF status with signs and /or symptoms of pulmonary congestion . A total of 233 patients noted such an OptiVol alert and for 210 , HF status was evaluated within 30 days . Heart failure status had worsened for 80 patients ( PPV = 38.1 % ) . CONCLUSIONS An intrathoracic impedance-derived fluid index had low sensitivity and PPV in the early period after implantation of a device in chronic HF patients  . Sensitivity improved within the first 6 months after implant . Further studies are needed to assess the place of this monitoring technology in the clinical management of patients with HF OBJECTIVES We sought to determine the utility of combined heart failure ( HF ) device diagnostic information to predict clinical deterioration of HF in patients with systolic left ventricular dysfunction . BACKGROUND Some implantable devices continuously monitor HF device diagnostic information , but data are limited on the ability of combined HF device diagnostics to predict HF events . METHODS The PARTNERS HF ( Program to Access and Review Trending Information and Evaluate Correlation to Symptoms in Patients With Heart Failure ) was a prospect i ve , multicenter observational study in patients receiving cardiac resynchronization therapy ( CRT ) implantable cardioverter-defibrillators .  HF events were independently adjudicated . A combined HF device diagnostic algorithm was developed on an independent data set . The algorithm was considered positive if a patient had 2 of the following abnormal criteria during a 1-month period : long atrial fibrillation duration , rapid ventricular rate during atrial fibrillation , high ( > or = 60 ) fluid index , low patient activity , abnormal autonomics ( high night heart rate or low heart rate variability ) , or notable device therapy ( low CRT pacing or implantable cardioverter-defibrillator shocks ) , or if they only had a very high ( > or = 100 ) fluid index . We used univariate and multivariable analyses to determine predictors of subsequent HF events within a month . RESULTS We analyzed data from 694 CRT defibrillator patients who were followed for 11.7 + /- 2 months . Ninety patients had 141 adjudicated HF  hospitalizations with pulmonary congestion  at least 60 days after implantation . Patients with a positive combined HF device diagnostics had a 5.5-fold increased risk of HF hospitalization with pulmonary signs or symptoms within the next month ( hazard ratio : 5.5 , 95 % confidence interval : 3.4 to 8.8 , p < 0.0001 ) , and the risk remained high after adjusting for clinical variables ( hazard ratio : 4.8 , 95 % confidence interval : 2.9 to 8.1 , p < 0.0001 ) . CONCLUSIONS Monthly review of HF device diagnostic data identifies patients at a higher risk of HF hospitalizations within the subsequent month . ( PARTNERS HF : Program to Access and Review Trending Information and Evaluate Correlation to Symptoms in Patients With Heart Failure ; NCT00279955 ) The relative sensitivity and unexplained detection rate of changes in intrathoracic impedance has not been compared with st and ard heart failure ( HF ) monitoring using daily weight changes . The Fluid Accumulation Status Trial ( FAST ) prospect ively followed 156 HF patients with implanted cardioverter-defibrillator or cardiac resynchronization therapy defibrillator devices modified to record daily changes in intrathoracic impedance in a blinded fashion for 537±312 days .  Daily impedance changes were used to calculate a fluid index that could be compared with a prespecified threshold . True positives were defined as adjudicated episodes of worsening HF occurring within 30 days of a fluid index above threshold or an acute weight gain . Unexplained detections were defined as threshold crossings or acute weight gains not associated with worsening HF . Impedance measurements were performed on > 99 % of follow-up days , compared with only 76 % of days for weight measurements . Sixty-five HF events occurred during follow-up ( 0.32/patient-year ) . Forty HF events were detected by impedance but not weight , whereas 5 were detected by weight but not impedance . Sensitivity was greater ( 76 % vs 23 % ; P<.0001 ) and unexplained detection rate was lower ( 1.9 vs 4.3/patient-year ; P<.0001 ) for intrathoracic impedance monitoring at the threshold of 60Ω days compared with acute weight increases of 3 lbs in 1 day or 5 lbs in 3 days and also over a wide range of fluid index and weight thresholds . The sensitivity and unexplained detection rate  of intrathoracic  impedance monitoring was superior to that seen for acute weight changes . Intrathoracic impedance monitoring represents a useful adjunctive clinical tool for managing HF in patients with implanted devices
target: RESULTS Device diagnostics showed strong correlation with established HF biomarkers and hemodynamic measures .
  The findings from this review indicate that device diagnostic parameters predict impending HF much earlier than traditional methods of monitoring do .
  Device diagnostics are also more accurate in the early prediction of HF when compared with noninvasive objective measures , particularly when multiple parameters are combined and monitored for trends .
  Device diagnostics possess a distinct advantage over traditional methods of monitoring for HF because they allow clinicians to remotely monitor the status of their HF patients without relying on patient compliance for data entry and reporting .
  Studies regarding the efficacy of device diagnostic parameters suggest that their integration into clinical practice will provide a more accurate and reliable mechanism for assisting clinicians in risk stratifying and predicting potential episodes of decompensated HF
background: BACKGROUND Traditional methods of heart failure ( HF ) management are based on reactive strategies to treat late indicators of decompensated HF .
  Advances in monitoring methods have become available with the evolution of implantable cardioverter-defibrillators and cardiac-resynchronization therapy devices .
  These devices provide new diagnostic data and remote monitoring capabilities that allow clinicians to proactively monitor patients for earlier signs of worsening HF .
  The integration of data obtained from implantable cardioverter-defibrillator and cardiac-resynchronization therapy technology could improve outpatient HF care , potentially leading to decreased readmission rates and improved patient outcomes .
  OBJECTIVE This review will synthesize the literature regarding the efficacy of device diagnostic data and the usability of the data in the clinical setting .