title: Monitoring of physical activity and heart rate variability in patients with chronic heart failure using cardiac resynchronization devices. Predictive value of device-derived activity level for short-term outcomes in MADIT-CRT. Device diagnostics and long-term clinical outcome in patients receiving cardiac resynchronization therapy. Defibrillator shocks and their effect on objective and subjective patient outcomes: Results of the PainFree SST clinical trial. Seasonal variation of daily physical activity in individuals with heart failure Pedometer-determined step count guidelines for classifying walking intensity in a young ostensibly healthy population. Activity monitoring in heart failure patients with cardiac resynchronization therapy. 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.
abstract: Cardiac resynchronization therapy ( CRT ) devices not only deliver effective treatment but may also serve as valuable diagnostic tools in heart failure management . In the present study , the minutes of daily physical activity and heart rate variability , measured by sensors incorporated into such a device , reflected the effects of CRT and were related to New York Heart Association functional class BACKGROUND There are limited data on the prognostic importance of declining activity level in patients with heart failure . OBJECTIVE We aim ed to assess the association of reduced activity level with adverse cardiovascular outcomes in the Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy ( MADIT-CRT ) . METHODS Final device interrogations from patients enrolled in the MADIT-CRT with cardiac resynchronization devices capable of recording percent daily activity level were assessed . To determine temporal change , st and ardized activity levels ( SALs ) comparing each week to the monthly activity 3 months prior were obtained . Death , heart failure events (HFEs)/death , and ventricular tachyarrhythmias (VTAs)/death were the primary end points of this study . RESULTS The average absolute activity level and SAL of the final week prior to death or end of study were significantly lower in patients who died compared with those in patients who did not . The total cohort ( N = 1008 ) was further r and omized into 2 subgroups to identify ( group 1 ) and vali date an optimal threshold ( group 2 ) . Patients with > 40 % reduced SAL had a significantly increased 77-day short-term cumulative incidence of death ( P = .0006 ) , HFE/death ( P < .0001 ) , or VTA/death ( P = .0248 ) . After adjustment for clinical covariates , these patients remained at an increased risk for death ( hazard ratio [ HR ] , 2.7 ; 95 % confidence interval [ CI ] , 1.5 - 4.9 ; P = .001 ) , HFE/death ( HR , 2.7 ; 95 % CI , 1.8 - 3.9 ; P ≤ .001 ) and VTA/death ( HR , 1.9 ; 95 % CI , 1.31 - 2.6 ; P = .001 ) . A decline in SAL following a nonfatal VTA and HFE was also associated with an increased probability of death . CONCLUSIONS Decline in activity level is a short-term predictor for adverse cardiovascular events in patients with mild to moderate heart failure undergoing cardiac resynchronization AIMS This retrospective analysis sought to develop and vali date 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 vali date d 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 BACKGROUND The effect of  implantable cardioverter-defibrillator ( ICD ) shock  on device-measured activity and patient-reported outcomes is unknown . OBJECTIVE The purpose of this study was to analyze the acute and long-term effects of ICD shock on objective behavioral data ( ie , device-based physical activity ) and subjective patient-reported outcomes ( eg , quality of life and shock anxiety ) . METHODS The PainFree Smart Shock Technology ( SST ) clinical trial included 2770 patients with a single- or dual-chamber ICD or cardiac resynchronization therapy - defibrillator device who were followed for 22 ± 9 months . Participants completed measures of quality of life ( EuroQol-5D [ EQ-5D ] question naire ) and shock anxiety ( Florida Shock Anxiety Scale ) at baseline , biannual visits , and monthly for 6 months after an ICD shock . Daily physical activity data were obtained from a built-in device accelerometer . RESULTS The average daily activity was 185.3 ± 119.4 min/d . Activity was significantly reduced after an ICD shock ( P < .0001 ) and recovered to a normal level after ∼90 days . An ICD shock was also associated with decreased quality of life ( EQ5-D health score ) and increased EQ-5D anxiety scores , but it did not affect mobility , self-care , activity , or pain . Similarly , shock anxiety ( Florida Shock Anxiety Scale ) increased in shocked patients and remained significantly elevated at 24 months , regardless of appropriate or inappropriate shock delivery . CONCLUSION ICD shocks have a long-lasting adverse effect on both objective , device-measured physical activity and subjective patient-reported outcomes of quality of life and shock anxiety . Successful management of patients with an ICD requires attention to clinical ly relevant behavioral and psychological outcomes to expedite recovery and return to activities of daily living Background Previous studies indicate that seasonal variation affects daily physical activity ( PA ) , but none have investigated this relationship in individuals with heart failure ( HF ) who also have implanted cardioverter defibrillators and cardiac resynchronization therapy ( ICD/CRT ) devices . The purpose of the present study was to determine if seasonal variation in temperature affects daily PA in patients with HF and ICD/CRTs . Patients and methods Secondary analysis of data from 16 subjects with HF and Medtronic ® ICD/CRT devices enrolled in a r and omized trial investigating interventions to improve daily PA . Due to the rolling study enrollment , daily PA data for all subjects were not available for the entire time frame and were divided into two groups . Determination of seasonal variation of daily PA was determined using visual analysis of daily PA plotted with average temperature , autocorrelation , visual analysis of seasonal subseries plots and boxplot analysis , as well as Wilcoxon signed-rank tests . Results Subjects 1 - 8 demonstrated the greatest differences in daily PA during periods of seasonal transition whereas subjects 9 - 16 demonstrated the greatest variation in daily PA with greatest seasonal temperature difference . Wilcoxon signed-rank testing of the lowest and highest months for daily PA revealed median differences of 0.30 ( p = 0.050 ) and 0.36 hours ( p = 0.036 ) for subjects 1 - 8 and 9 - 16 , with effect sizes of 0.69 and 0.74 , respectively . Conclusions Seasonal variation in mean temperature appears to affect daily PA in individuals with HF and ICD/CRT devices by a magnitude of 0.30 - 0.36 hours , which may need to be accounted for in future research investigating interventions to improve daily PA PURPOSE ( a ) To establish pedometer steps/min intensity categories ( i.e. , light , moderate , hard , very hard ) for adults under controlled conditions , and ( b ) use these cut-points to ascertain the number of steps expected in 30 minutes of moderate intensity activity . METHODS 25 men and 25 women , ages 18 - 39 years , performed 6-min exercise bouts at 3 treadmill speeds ( 4.8 , 6.4 , and  9.7 km/hr ) . Yamax SW-200 pedometers indicated steps  , and steady-state VO2 was recorded . METs were calculated by dividing steady-state VO2 by 3.5 ml x kg(-1 ) x min(-1 ) . Linear regression was used to quantify the relationships between steps/min and METs across all speeds . Ten participants ( 5 M , 5 F ) were r and omly selected from the original 50 and constituted a holdout sample for cross-validation purpose s ( i.e , comparing actual and predicted METs ; paired t-test ) . RESULTS The regression equation for males was : METs = -7.065 + ( 0.105 x steps/min ) r2 = 0.803 . For females it was : METs = -8.805 + ( 0.110 x steps/min ) r2 = 0.830 . Cross-validation was confirmed . CONCLUSIONS Pedometer cut-points corresponding to minimal moderate intensity walking were 96 steps/min in men and 107 steps/min in women , or roughly 100 steps/min for both . This translates to approximately 3,000 steps in 30 min of moderate-intensity ambulatory activity for both genders BACKGROUND Cardiac resynchronization therapy ( CRT ) improves functional capacity in heart failure patients . This study aim ed to prospect ively analyze long-term device-based monitoring of physical activity in patients undergoing CRT .  METHODS AND RESULTS The Activity Log Index ( ALI ) , calculated by CRT devices , represents the percentage of time when acceleration exceeds a threshold and monitors the physical activity . Data from 178 CRT patients ( New York Heart Association III 91 % , left ventricular ejection fraction 21+/-6 % , left ventricular end-diastolic diameter 69+/-9 mm , QRS 159+/-27 ms , sinus rhythm 81 % ) were retrieved . The ALI increased from a baseline value of 3.6+/-2.0 to 11.2+/-4.6 ( p<0.005 ) 104 weeks after initiation of CRT . A plateau was reached at approximately 12 weeks and thereafter ALI remained stable for up to 2 years . The magnitude of the changes in ALI was similar in patients with different etiologies and underlying rhythms . Despite similar values at baseline , elderly patients ( > or=65 years ) exhibited significantly lower ALI values than younger patients during the follow-up and at the plateau ( 9.5+/-4.2 vs 13.3+/-4.8 , p<0.001 ) . CONCLUSIONS Device-based monitoring of physical activity in CRT patients is feasible . CRT result ed in a large and long-term increase in physical activity 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 )
target: 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 .
background: 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 method ological issues that may affect interpretation of study results .