Measuring Physical Activity With Implanted Cardiac Devices: A Systematic Review

Ambulatory Risk Stratification for Worsening Heart Failure in Patients with Reduced and Preserved Ejection Fraction Using Diagnostic Parameters Available in Implantable Cardiac Monitors

BACKGROUND

Ambulatory risk stratification for worsening heart failure (HF) using diagnostics measured by insertable cardiac monitors (ICM) may depend on the left ventricular ejection fraction (LVEF). We evaluated risk stratification performance in patients with reduced versus preserved LVEF.

METHODS

ICM patients with a history of HF events (HFEs) were included from the Optum® de-identified Electronic Health Record dataset merged with ICM device-collected data during 2007-2021. ICM measures nighttime heart rate (NHR), heart rate variability (HRV), atrial fibrillation (AF) burden, rate during AF, and activity duration (ACT) daily. Each diagnostic was categorized into high, medium, or low risk using previously defined features. HFEs were HF-related inpatient, observation unit, or emergency department stays with IV diuresis administration. Patients were divided into two cohorts: LVEF ≤ 40% and LVEF > 40%. A marginal Cox proportional hazards model compared HFEs for different risk groups.

RESULTS

A total of 1020 ICM patients with 18,383 follow-up months and 301 months with HFEs (1.6%) were included. Monthly evaluations with a high risk were 2.3, 4.2, 5.0, and 4.5 times (p < 0.001 for all) more likely to have HFEs in the next 30 days compared to those with a low risk for AF, ACT, NHR, and HRV, respectively. HFE rates were higher for patients with LVEF > 40% compared to LVEF ≤ 40% (2.0% vs. 1.3%), and the relative risk between high-risk and low-risk for each diagnostic parameter was higher for patients with LVEF ≤ 40%.

CONCLUSIONS

Diagnostics measured by ICM identified patients at risk for impending HFEs. Patients with preserved LVEF showed a higher absolute risk, and the relative risk between risk groups was higher in patients with reduced LVEF.

Changes in physical activity around the time of major adverse cardiac events in patients with implantable cardioverter-defibrillators

BACKGROUND

With modern implantable cardioverter-defibrillators (ICDs), biometric measures including physical activity have become readily available to physicians. However, despite the increased availability, applications of these data to the clinical setting remain poorly studied. We sought to investigate whether changes in physical activity occur preceding and following cardiac events in patients with ICDs.

METHODS

We reviewed the electronic medical records of patients with ICDs implanted for any indication in 2018 and 2019 in the University of Pennsylvania health system. Patients with ICDs that reported physical activity were included in the study only if they experienced major adverse cardiac event(s) (MACE) that were preceded by at least 6 months without MACE after device implantation.

RESULTS

Seventy-four of the 827 charts reviewed met inclusion criteria. Baseline activity levels from 6 to 2 months prior to MACE were 2.18-2.21 h/day. In the month prior to MACE, average activity decreased significantly to 2.09 h/day, and subsequently decreased again during the calendar month in which MACE occurred to 1.96 h/day. The lowest average monthly activity levels occurred in the month after MACE, with incremental but non-significant recovery occurring over the subsequent 2 months.

CONCLUSIONS

In a cohort of ICD recipients, a significant decrease in physical activity was observed in the month preceding MACE. To our knowledge, this is the first study that observes time-dependent changes in activity in relation to MACE in a generalizable cohort of ICD recipients. ICD activity monitoring in patients at high risk for MACE may enhance patient care.

Current state of the art and future directions for implantable sensors in medical technology: Clinical needs and engineering challenges

Implantable sensors have revolutionized the way we monitor biophysical and biochemical parameters by enabling real-time closed-loop intervention or therapy. These technologies align with the new era of healthcare known as healthcare 5.0, which encompasses smart disease control and detection, virtual care, intelligent health management, smart monitoring, and decision-making. This review explores the diverse biomedical applications of implantable temperature, mechanical, electrophysiological, optical, and electrochemical sensors. We delve into the engineering principles that serve as the foundation for their development. We also address the challenges faced by researchers and designers in bridging the gap between implantable sensor research and their clinical adoption by emphasizing the importance of careful consideration of clinical requirements and engineering challenges. We highlight the need for future research to explore issues such as long-term performance, biocompatibility, and power sources, as well as the potential for implantable sensors to transform healthcare across multiple disciplines. It is evident that implantable sensors have immense potential in the field of medical technology. However, the gap between research and clinical adoption remains wide, and there are still major obstacles to overcome before they can become a widely adopted part of medical practice.

ehealth technology in cardiac exercise therapeutics for pediatric patients with congenital and acquired heart conditions: a summary of evidence and future directions

Many children and adolescents with congenital and acquired heart disease (CHD) are physically inactive and participate in an insufficient amount of moderate-to-vigorous intensity exercise. Although physical activity (PA) and exercise interventions are effective at improving short- and long-term physiological and psychosocial outcomes in youth with CHD, several barriers including resource limitations, financial costs, and knowledge inhibit widespread implementation and dissemination of these beneficial programs. New and developing eHealth, mHealth, and remote monitoring technologies offer a potentially transformative and cost-effective solution to increase access to PA and exercise programs for youth with CHD, yet little has been written on this topic. In this review, a cardiac exercise therapeutics (CET) model is presented as a systematic approach to PA and exercise, with assessment and testing guiding three sequential PA and exercise intervention approaches of progressive intensity and resource requirements: (1) PA and exercise promotion within a clinical setting; (2) unsupervised exercise prescription; and (3) medically supervised fitness training intervention (i.e., cardiac rehabilitation). Using the CET model, the goal of this review is to summarize the current evidence describing the application of novel technologies within CET in populations of children and adolescents with CHD and introduce potential future applications of these technologies with an emphasis on improving equity and access to patients in low-resource settings and underserved communities.

Onset of the COVID-19 pandemic reduced active time in patients with implanted cardiac devices

BACKGROUND

Physical inactivity and sedentary behavior are modifiable risk factors for chronic disease and all-cause mortality that may have been negatively impacted by the COVID-19 shutdowns.

METHODS

Accelerometry data was retrospectively collected from 332 permanent pacemaker (PPM) and 244 implantable cardiac defibrillation (ICD) patients for 6 time points: March 15-May 15, 2020 (pandemic period), January 1-March 14, 2020, October 1-December 31, 2019, March 15-May 15, 2019, January 1-March 14, 2019, and October 1-December 31, 2018. Paired t-tests, with Bonferroni correction, were used to compare time periods.

RESULTS

Activity significantly decreased during the pandemic period compared to one year prior by an average of 0.53 ± 1.18h/day (P < 0.001) for PPM patients and 0.51 ± 1.2h/day (P < 0.001) for ICD patients. Stratification of subjects by active time (< 2 versus ≥ 2h/day) showed patients with < 2h, particularly those with ICDs, had modestly greater activity reductions with the pandemic onset. Logistical regression analyses suggest a trend toward a greater reduction in active time at the onset of the pandemic and an increased risk of hospital or emergency department (ED) admission for PPM patients, but not ICD patients.

CONCLUSION

The onset of the pandemic in the United States was associated with a significant drop in PPM and ICD patient active hours that was modestly more pronounced in less active patients and cannot be explained by one year of aging or seasonal variation. If sustained, these populations may experience excess cardiovascular morbidity.

Comparative Analysis of Physical Activity Detected via an External Accelerometer and Cardiac Implantable Electronic Devices

Background

Physical activity (PA) has become an important health issue for decades. Cardiovascular implantable electronic devices (CIEDs) have built-in PA-recording functions. We aimed to compare PA measurements using an external accelerometer (ActiGraph GT3X+) and internal accelerometers (Abbott, Biotronik, and Medtronic CIEDs).

Methods

This was a prospective, single-center observational study. The device-measured 7-day average PA was collected, and GT3X+ -measured 7-day average PA was used as the gold-standard, including all daily observations of activity. Pearson’s correlation coefficients were used to compare the correlations between GT3X+ -measured and CIED-measured PA. Bland-Altman plots were used to analyze measurement agreement, and intraclass correlation coefficients were used to analyze reliability.

Results

In total, 720 patients treated with CIEDs were surveyed between November 2020 and April 2021, 60 of them were analyzed after patient screening by our protocol. Each manufacturer included 20 patients for the final analysis. The CIED-measured PAs of Abbott, Biotronik, and Medtronic were 3.0 ± 1.5, 2.6 ± 1.8, and 3.8 ± 2.5 h per day, respectively; the GT3X+ -measured PAs were 6.9 ± 2.8, 6.0 ± 2.4, and 6.4 ± 2.5 h per day, respectively. Moderate and significant correlations were found in patients using Abbott, Biotronik, and Medtronic CIEDs (r = 0.534, p = 0.015; r = 0.465, p = 0.039; r = 0.677, p = 0.001, respectively). Bland-Altman plots and intraclass correlation coefficients both showed a significant correlation and reliability between the average PA measured by GT3X+ and CIEDs (hours per day).

Conclusion

Although the PA recording function of CIEDs includes a single-axis accelerometer, it has a moderate correlation compared with the triaxial accelerometer of the GT3X+. However, CIEDs seem to underestimate PA for 3–4 h compared to the GT3X+.

Association of time-varying changes in physical activity with cardiac death and all-cause mortality after ICD or CRT-D implantation

OBJECTIVE

To evaluate the association of longitudinal changes in physical activity (PA) with long-term outcomes after implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRT-D) implantation.

METHODS

Patients with ICD/CRT-D implantation from SUMMIT registry were retrospectively analyzed. Accelerometer-derived PA changes over 12 months post implantation were obtained from the archived home monitoring data. The primary endpoints were cardiac death and all-cause mortality. The secondary endpoints were the first ventricular arrthymia (VA) and first appropriate ICD shock.

RESULTS

In 705 patients, 446 (63.3%) patients showed improved PA over 12 months after implantation. During a mean 61.5-month follow-up duration, 99 cardiac deaths (14.0%) and 153 all-cause deaths (21.7%) occurred. Compared to reduced/unchanged PA, improved PA over 12 months could result in significantly reduced risks of cardiac death (improved PA ≤ 30 min: hazard ratio (HR) = 0.494, 95% CI: 0.288-0.848; > 30 min: HR = 0.390, 95% CI: 0.235-0.648) and all-cause mortality (improved PA ≤ 30 min: HR = 0.467, 95%CI: 0.299-0.728; > 30 min: HR = 0.451, 95% CI: 0.304-0.669). No differences in the VAs or ICD shocks were observed across different groups of PA changes. PA changes can predict the risks of cardiac death only in the low baseline PA group, but improved PA was associated with 56.7%, 57.4%, and 62.3% reduced risks of all-cause mortality in the low, moderate, and high baseline PA groups, respectively, than reduced/unchanged PA.

CONCLUSIONS

Improved PA could protect aganist cardiac death and all-cause mortality, probably reflecting better clinical efficacy after ICD/CRT-D implantation. Low-intensity exercise training might be encouraged among patients with different baseline PA levels.

Implantable device measured objective daily physical activity as a predictor of long-term all-cause mortality and cardiac death in patients with age > 75 years and high risk of sudden cardiac death: a cohort study : Physical activity and patients over 75 years old

BACKGROUND

To study the relationship between objective daily physical activity (PA), as measured by implantable cardioverter defibrillators (ICDs)/cardiac resynchronization therapy defibrillators (CRTDs), and long-term prognoses in patients with age > 75 years at high risk of sudden cardiac death (SCD).

METHODS

In total, 133 patients with age > 75 years old (age 79.52 ± 3.68 years) in the SUMMIT study were retrospectively analysed. The major endpoint was all-cause mortality, and the minor endpoint was cardiac death.

RESULTS

The mean follow-up time was 57.1 ± 24.2 months (range: from 4 to 96 months). In total, 46 all-cause mortality and 23 cardiac death events occurred. The receiver operating characteristic curve indicated a baseline PA cut-off value of 6.47% (93 min/day) can predict all-cause mortality in patients with age > 75 years, with an area under the curve of 0.670 (95% confidence interval (CI): 0.573-0.767, P = 0.001). The sensitivity was 67.4%, and the specificity was 66.7%. Patients with baseline PA ≤ 6.47% had higher rates of all-cause mortality (51.7% vs 20.5%, P < 0.001) and cardiac death (25.0% vs 11.0%, P = 0.040). The estimated Kaplan-Meier survival curves showed that patients with PA ≤ 6.47% had an increased cumulative incidence of all-cause mortality (Log-rank P < 0.0001) and cardiac death (Log-rank P = 0.0067). Multivariate Cox regression analysis showed that PA ≤ 6.47% was an independent predictor of all-cause mortality (hazard ratio (HR) 3.137, 95% CI: 1.667-5.904, P < 0.001) and cardiac death (HR value 3.345, 95% CI: 1.394-8.028, P = 0.007).

CONCLUSIONS

Daily PA of about 1.5 h was associated with lower all-cause mortality and cardiac death risk in patients with age > 75 years and high risk of SCD with ICDs/CRTDs. PA monitoring may aid in long-term management of older patients at high risk of SCD.

Activity During the COVID-19 Pandemic in Children with Cardiac Rhythm Management Devices

Decreased physical activity is associated with cardiovascular, metabolic and mental health disease. While decreases in physical activity during the COVID-19 pandemic have been described in the general population, there is a paucity of data regarding children with underlying cardiovascular disease. We hypothesized there would be a decrease in physical activity at the onset of the COVID-19 pandemic. Performed a single-center, retrospective cohort study of children aged < 19 years with cardiac rhythm management devices. Patients were included if they had device-measured physical activity data from > 80% of dates from February 3, 2020 through June 30, 2020. Patients with significant neurologic/neuromuscular disease were excluded. We identified 144 patients with a median age of 15.4 years. 47% were female. 34% had congenital heart disease, 20% had cardiomyopathy, 19% had an inherited arrhythmia syndrome and 5% had atrioventricular block without congenital heart disease. 47% of patients had an implantable loop recorder, 29% had a permanent pacemaker and 24% had an implantable cardioverter-defibrillator. We observed a significant decrease in device-measured physical activity from baseline (February 3-March 9), with up to a 21% decrease in physical activity during mid-March through early May. Activity levels returned to pre-pandemic levels in June. Physical activity sharply declined in children with cardiac rhythm management devices at the onset of the COVID-19 pandemic. These data highlight the importance of finding strategies to maintain physical activity during the current pandemic and future public health crises.

Immediate and long-term effects of the COVID-19 pandemic and lockdown on physical activity in patients with implanted cardiac devices

Background

Physical activity (PA) is an important determinant of cardiovascular health that may be affected the COVID‐19 pandemic. Therefore, we examined the immediate and long‐term effects of the pandemic and lockdown on PA in patients with established cardiovascular risk.

Methods

Objectively‐measured daily PA data was obtained from cardiovascular implantable electronic devices (CIEDs) from 3453 U.S patients (mean and standard deviations [SD] age, 72.65 [13.24] years; 42% women). Adjusted mixed‐effects models stratified by device type were used to compare daily PA from periods in 2020: pre‐lockdown (March 1–14), lockdown (March 15 to May 8), and the reopening phase of the pandemic (May 9 to December 31) versus 2019. Patient characteristics and events associated with inactivity during lockdown and the proportion of patients who returned to their 2019 PA‐level by the end of reopening phase (December 31, 2020) were examined.

Results

Daily PA was significantly lower during the lockdown compared to the same period in 2019 (−15%; p < .0001), especially for pacemaker patients, adults aged <65, and patients more active prior to lockdown. Non‐COVID hospitalization and ICD shock were similarly associated with low PA during lockdown (p = .0001). In the reopening phase of the pandemic, PA remained 14.4% lower in the overall sample and only 23% of patients returned to their 2019 PA level by the end of follow‐up.

Conclusions

In this large cohort of patients with CIEDs, PA was markedly lower during the lockdown and remained lower for months after restrictions were lifted. Strategies to maintain PA during a national emergency are urgently needed.

Lockdown measures for COVID-19 outbreak and variation in physical activity in patients with heart failure and cardiac implantable devices

Aims

The present study analysed the patterns of physical activity pre-, during and post-lockdown measures for COVID-19 pandemic in patients with chronic heart failure (CHF) and cardiac implantable electronic devices (CIED) under remote monitoring (RM), and assessed the physical activity patterns during these periods.

Methods

The raw data from 95 patients with CHF (age 67,7 ± 15,1 years, 71,5% male) corresponding to 2238 RM transmissions of the Medtronic Carelink™ network platform was obtained. The physical exercise profiles and the impact of the lockdown measures on the physical behaviour during and after the measures were analysed. According to the level of activity duration in the pre-lockdown, lockdown and post-lockdown periods, the patterns of behaviour were identified (non-recoverees, incomplete recoverees, recoverees and full-recoverees).

Conclusion

RM of CHF patients with CIED using the Carelink™ network is useful for close follow-up and identification of heart failure risk status variations. After relieving the confinement measures there were two groups of patients that did not recover the previous physical activity levels. Physical inactivity in patients with CHF can have a significant impact on outcomes.

The Association between Physical Activity and Cardiovascular Implantable Electronic Device-Detected Atrial High Rate Episodes

BACKGROUND

Atrial fibrillation is the most common arrhythmia and it is associated with a higher risk of mortality and morbidity. The goal of this study was to assess the correlation between physical activity (PA) and atrial high rate episodes (AHREs) detected by cardiovascular implantable electronic devices (CIEDs).

METHODS

We prospectively collected data from 81 patients from March 2017 to June 2019. Device-detected PA (hours per day) through an accelerometer and occurrence/burden of AHREs were determined at each outpatient clinic visit. Modest AHREs and long AHREs were defined as at least 1 episode of AHREs lasting ≥ 12 hours and 24 hours, respectively. The percentage of total AHREs in the follow-up period was defined as the burden of AHREs. Generalized estimating equations were used to explore the association between PA and occurrence/burden of AHREs to account for repeated measures within a participant.

RESULTS

The patients had 336 follow-up visits (mean 4.1 visits each). The prevalence rates of device-detected modest AHREs and long AHREs were 4.8% and 3.9%, respectively. More PA (hours per day) was associated with a lower risk of modest AHREs [odds ratio (OR) 0.671, 95% confidence interval (CI) 0.452-0.997, p = 0.048] and long AHREs (OR 0.536, 95% CI 0.348-0.824, p = 0.004) after adjusting for age, sex, and basic characteristics. More PA had a trend of association with fewer AHREs (β -0.255, 95% CI -0.512 to 0.001, p = 0.051).

CONCLUSIONS

More PA was associated with a lower risk of AHREs detected by CIEDs in older patients. PA may reduce the risk of AHREs.

Lockdown, slow down: impact of the COVID-19 pandemic on physical activity-an observational study

Aims

In response to the COVID-19 pandemic, the UK was placed under strict lockdown measures on 23 March 2020. The aim of this study was to quantify the effects on physical activity (PA) levels using data from the prospective Triage-HF Plus Evaluation study.

Methods

This study represents a cohort of adult patients with implanted cardiac devices capable of measuring activity by embedded accelerometery via a remote monitoring platform. Activity data were available for the 4 weeks pre-implementation and post implementation of ‘stay at home’ lockdown measures in the form of ‘minutes active per day’ (min/day).

Results

Data were analysed for 311 patients (77.2% men, mean age 68.8, frailty 55.9%. 92.2% established heart failure (HF) diagnosis, of these 51.2% New York Heart Association II), with comorbidities representative of a real-world cohort.

Post-lockdown, a significant reduction in median PA equating to 20.8 active min/day was seen. The reduction was uniform with a slightly more pronounced drop in PA for women, but no statistically significant difference with respect to age, body mass index, frailty or device type. Activity dropped in the immediate 2-week period post-lockdown, but steadily returned thereafter. Median activity week 4 weeks post-lockdown remained significantly lower than 4 weeks pre-lockdown (p≤0.001).

Conclusions

In a population of predominantly HF patients with cardiac devices, activity reduced by approximately 20 min active per day in the immediate aftermath of strict COVID-19 lockdown measures.

Trial registration number

NCT04177199.

Utility of cardiovascular implantable electronic device-derived patient activity to predict clinical outcomes

BACKGROUND

The role of cardiovascular implantable electronic device (CIED)-derived activity to predict implantable cardioverter-defibrillator (ICD) therapy or death is not known.

OBJECTIVE

We aimed to assess CIED-derived activity to predict clinical outcomes.

METHODS

In 1500 patients enrolled in MADIT-RIT, CIED-derived patient activity was acquired daily, then averaged for the first 30 days following randomization to predict inappropriate/appropriate therapy or death. Kaplan-Meier analysis and Cox proportional regression models were used to evaluate inappropriate/appropriate therapy, heart failure, or death by 30-day CIED-derived patient activity quintiles.

RESULTS

There were 1463 patients with CIED activity data (98%). Patients in the highest quintile (Q5) of activity (more active) had the highest rate of inappropriate therapy, 21% at 2 years, as compared to 7%-11% in the other 4 quintiles (P < .001), a 1.75 times higher risk (95% confidence interval [CI]: 1.23-2.50, P = .002). However, patients in the lowest quintile of activity (Q1, 1 hour/day) had the highest risk of mortality, 15% in 2 years, as compared to Q2-3 (1-2 hours/day, 8%-7% mortality), and Q4-5 (>2 hours/day, 2%-3% mortality) (P < .001). Patients with the lowest level of activity (Q1) had a 2.02 times higher risk of mortality (95% CI: 1.21-3.38, P = .007), and they had an 82% higher risk of heart failure hospitalization (95% CI: 1.28-2.57, P = .001).

CONCLUSIONS

High CIED-derived 30-day median patient activity predicted inappropriate therapy, while low patient activity predicted mortality and heart failure in ICD and cardiac resynchronization therapy with defibrillator patients enrolled in MADIT-RIT. Device-derived activity assessment could serve as a useful predictor of outcomes.

Clinical utility of CorVue intrathoracic impedance alert with device-measured physical activity in predicting heart failure events

Cardiac implantable electronic devices (CIEDs) offer heart failure (HF) diagnostic information, including intrathoracic impedance (ITI) or physical activity (PA). However, few studies have evaluated the utility of these parameters measured by CIEDs with CorVue algorithm. The purpose of this study was to investigate the relationship between ITI alerts triggered by the CorVue algorithm and HF development. We also examined the association between device-measured PA and ITI alerts associated with HF development. We retrospectively studied consecutive patients with CIEDs equipped with CorVue algorithm, which were implanted between June 1, 2011 and August 31, 2019. These patients were divided into two groups: patients with decreased ITI followed by the ITI alerts (ITI alert group) and those without the alerts (non-ITI alert group). There were 35 and 14 patients in the ITI and non-ITI alert groups, respectively. A total of 96 ITI alerts were observed. ITI alerts associated with HF development were observed in 21% (20/96); whereas, ITI alerts not associated with HF development were observed in 79% (76/96). Accurate device-measured PA was confirmed in 76 ITI alerts, which consisted of 30 alerts with lower PA and 46 alerts without lower PA. ITI alerts associated with HF development were observed in 30% (9/30) of the alerts with lower PA, whereas observed only in 6.5% (3/46) of the alerts without lower PA. In conclusion, the CorVue ITI alerts indicated a high false-positive rate. However, device-measured PA may be useful to determine whether ITI alerts are associated with HF development or not, which was attributed to the high negative predictive value.

Digital Health in Cardiac Rehabilitation and Secondary Prevention: A Search for the Ideal Tool

Digital health is becoming more integrated in daily medical practice. In cardiology, patient care is already moving from the hospital to the patients' homes, with large trials showing positive results in the field of telemonitoring via cardiac implantable electronic devices (CIEDs), monitoring of pulmonary artery pressure via implantable devices, telemonitoring via home-based non-invasive sensors, and screening for atrial fibrillation via smartphone and smartwatch technology. Cardiac rehabilitation and secondary prevention are modalities that could greatly benefit from digital health integration, as current compliance and cardiac rehabilitation participation rates are low and optimisation is urgently required. This viewpoint offers a perspective on current use of digital health technologies in cardiac rehabilitation, heart failure and secondary prevention. Important barriers which need to be addressed for implementation in medical practice are discussed. To conclude, a future ideal digital tool and integrated healthcare system are envisioned. To overcome personal, technological, and legal barriers, technological development should happen in dialog with patients and caregivers. Aided by digital technology, a future could be realised in which we are able to offer high-quality, affordable, personalised healthcare in a patient-centred way.

Association of the Obesity Paradox With Objective Physical Activity in Patients at High Risk of Sudden Cardiac Death

OBJECTIVE

To investigate the obesity paradox and its interrelationship with objective physical activity (PA) in patients at high risk of sudden cardiac death.

METHODS

A total of 782 patients with implantable cardioverter-defibrillators/cardiac resynchronization therapy defibrillators in the Study of Home Monitoring System Safety and Efficacy in Cardiac Implantable Electronic Device-Implantable Patients registry were retrospectively analyzed and grouped by body mass index (BMI) (kg/m2): normal weight (18.5 ≤ BMI < 25) and overweight or class I obesity (25 ≤ BMI < 35). PA was measured with home monitoring and categorized into 4 groups (Q1-Q4) by the baseline quartiles. The main endpoint was all-cause mortality.

RESULTS

During a mean follow-up period of 59.9 ± 21.9 months, 182 all-cause mortality events occurred. Mortality tended to be lower in overweight and obesity patients (18.9% vs 25.1%, P = 0.061) and decreased by PA quartiles (44.1% vs 22.6% vs 15.3% vs 11.2%, Q1-Q4, P < 0.001). Multivariate Cox analysis indicated BMI (hazard ratio, 0.918; 95% confidence interval, 0.866-0.974; P = 0.004) and PA (0.436, 0.301-0.631, Q2 vs Q1; 0.280, 0.181-0.431, Q3 vs Q1; 0.257, 0.158-0.419, Q4 vs Q1; P < 0.001 for all) were associated with reduced risk. The obesity paradox was significant in the total cohort (log rank P = 0.049) and low PA group (log rank P = 0.010), but disappeared in the high PA group (log rank P = 0.692). Dose-response curves showed a significant reduction in risk with low-moderate PA, and the pattern varied between different BMI groups.

CONCLUSIONS

The obesity paradox only persisted in physically inactive patients. PA might be related to the development of the obesity paradox.

Measuring physical activity with activity monitors in patients with heart failure: from literature to practice. A position paper from the Committee on Exercise Physiology and Training of the Heart Failure Association of the European Society of Cardiology

The aims of this paper were to provide an overview of available activity monitors used in research in patients with heart failure and to identify the key criteria in the selection of the most appropriate activity monitor for collecting, reporting, and analysing physical activity in heart failure research. This study was conducted in three parts. First, the literature was systematically reviewed to identify physical activity concepts and activity monitors used in heart failure research. Second, an additional scoping literature search for validation of these activity monitors was conducted. Third, the most appropriate criteria in the selection of activity monitors were identified. Nine activity monitors were evaluated in terms of size, weight, placement, costs, data storage, water resistance, outcomes and validation, and cut‐off points for physical activity intensity levels were discussed. The choice of a monitor should depend on the research aims, study population and design regarding physical activity. If the aim is to motivate patients to be active or set goals, a less rigorously tested tool can be considered. On the other hand, if the aim is to measure physical activity and its changes over time or following treatment adjustment, it is important to choose a valid activity monitor with a storage and battery longevity of at least one week. The device should provide raw data and valid cut‐off points should be chosen for analysing physical activity intensity levels. Other considerations in choosing an activity monitor should include data storage location and ownership and the upfront costs of the device.

Remotely monitored inactivity due to COVID-19 lockdowns. Potential hazard for heart failure patients

OBJECTIVES

To study the impact of curfews during the COVID-19 pandemic, on the physical activity in patients of heart failure implanted withcardiac implantable electronic devices (CIEDs).

METHODS

This was a retrospective single-center study of heart failure patients inserted with remote monitoring (RM)-capable CIED. We analyzed the transmitted data of physical activity and fluid volume status of all patients, before, and during the lockdown periods between February and April 2020. The clinical status of the patients was also evaluated.  Results: Device data from 429 patients implanted with CIED capable of RM were initially evaluated. Patients with an implantable loop recorder, Brugada or Long QT syndromes, and patients with incomplete transmissions were excluded. Eighty-two patients with heart failure were included. The median age was 65 years (58-72), and 53 (64.6%) subjects were men. There was a 27.1% decline in physical activity, and the median physical activity of patients significantly declined from 2.4 to 1.8 hours/day (p=0.000010).  Conclusion: Data obtained by remotely monitored CIED in heart failure patients suggests a significant decline in physical activity during the country lockdown due to the pandemic. Awareness of the future potential hazards in this group of patients is warranted.

Levels of Physical Activity and Physical Fitness in Pediatric Pacemaker Patients: A Cross-Sectional Study

Children with heart diseases have reduced physical activity (PA) levels relative to their peers, which in turn increases cardiovascular risk. To the best of our knowledge, physical fitness and objectively measured PA levels have not been previously studied in children with pacemakers. We evaluated PA levels and physical fitness in pediatric pacemaker patients compared to their healthy peers. Twenty-eight pediatric patients with pacemakers (15 female, 13 male; mean age 13.43 ± 3.68 years) and 24 healthy subjects (14 female, 10 male; mean age 13.08 ± 3.67 years) were included. Physical fitness was assessed using the Munich Fitness Test (MFT). SenseWear Armband metabolic Holter device was used to record the PA for 7 consecutive days. MFT total and sub-parameter scores were significantly lower in the patient group (p < 0.05). Patients' total and active energy expenditure, PA level, total distance, number of steps, and vigorous PA were significantly lower than those of healthy children (p < 0.05). Sedentary activity and light, moderate, and very vigorous PA durations were similar in both groups (p > 0.05). Duration of mean moderate to vigorous PA was higher than 60 min/day recommended in PA guidelines in both patients and healthy subjects. These results provide initial data on PA and fitness in children with pacemakers and suggest that physical fitness and activity levels in children with pacemakers are lower than in healthy peers. Appropriate exercise programs may improve PA levels in pediatric pacemaker patients. Awareness of the importance of PA should be raised among the parents and families of these children.

Baseline and decline in device-derived activity level predict risk of death and heart failure in patients with an ICD for primary prevention

BACKGROUND

Implanted defibrillators are capable of recording activity data based on company-specific proprietary algorithms. This study aimed to determine the prognostic significance of baseline and decline in device-derived activity level across different device companies in the real world.

METHODS

We performed a retrospective cohort study of patients (n = 280) who underwent a defibrillator implantation (Boston, Medtronic, St. Jude, and Biotronik) for primary prevention at the University of Michigan from 2014 to 2016. Graphical data obtained from device interrogations were retrospectively converted to numerical data. The activity level averaged over a month from a week postimplantation was used as baseline. Subsequent weekly average activity levels (SALs) were standardized to this baseline. SAL below 59.4% was used as a threshold to group patients. All-cause mortality and death/heart failure were the primary end-points of this study.

RESULTS

Fifty-six patients died in this study. On average, they experienced a 50% decline in SAL prior to death. Patients (n = 129) who dropped their SAL below threshold were more likely to be older, male, diabetic, and have more symptomatic heart failure. They also had a significantly increased risk of heart failure/death (hazard ratio [HR] 3.6, 95% confidence interval [95% CI] 2.3-5.8, P < .0001) or death (HR 4.2, 95% CI 2.2-7.7, P < .0001) compared to those who had sustained activity levels. Lower baseline activity level was also associated with significantly increased risk of heart failure/death and death.

CONCLUSION

Significant decline in device-derived activity level and low baseline activity level are associated with increased mortality and heart failure in patients with an ICD for primary prevention.

Effect of physical and psychocognitive function and perceived health status on 12-month adverse cardiac events among implantable cardioverter-defibrillator recipients

BACKGROUND

Post-implant recovery in patients with implantable cardioverter-defibrillators (ICDs) is often compromised because of reduced physical and psycho-cognitive function and poor health perception, leading to short event-free survival.

OBJECTIVES

To examine the effects of psychocognitive function, health perception, and ICD-related factors on 12-month cardiac events among ICD patients.

METHODS

Using a prospective study design, ICD patients underwent baseline assessment and were followed for 12 months to assess cardiac events.

RESULTS

Cardiac events occurred in 14 patients (18.9%) (N = 74: age, 58 years; primary ICDs, 45.9%). Time after ICD implant (odds ratio [OR] = 1.002; p = .028) and executive function (OR = 1.021; p = .027) were significant predictors of 12-month cardiac events, while other physical and psychological indices were not.

CONCLUSIONS

Reduced executive function and longer time after implant predicted the events. Healthcare professionals need to assess executive function and provide treatment and support to improve executive function.

Artificial Intelligence, Data Sensors and Interconnectivity: Future Opportunities for Heart Failure

A higher proportion of patients with heart failure have benefitted from a wide and expanding variety of sensor-enabled implantable devices than any other patient group. These patients can now also take advantage of the ever-increasing availability and affordability of consumer electronics. Wearable, on- and near-body sensor technologies, much like implantable devices, generate massive amounts of data. The connectivity of all these devices has created opportunities for pooling data from multiple sensors – so-called interconnectivity – and for artificial intelligence to provide new diagnostic, triage, risk-stratification and disease management insights for the delivery of better, more personalised and cost-effective healthcare. Artificial intelligence is also bringing important and previously inaccessible insights from our conventional cardiac investigations. The aim of this article is to review the convergence of artificial intelligence, sensor technologies and interconnectivity and the way in which this combination is set to change the care of patients with heart failure.

Pacemaker detected active minutes are superior to pedometer-based step counts in measuring the response to physical activity counseling in sedentary older adults

BACKGROUND

In patients with permanent pacemakers (PPM), physical activity (PA) can be monitored using embedded accelerometers to measure pacemaker detected active hours (PDAH), a strong predictor of mortality. We examined the impact of a PA Counseling (PAC) intervention on increasing activity as measured by PDAH and daily step counts.

METHODS

Thirteen patients (average age 80 ± 6 years, 84.6% women) with implanted Medtronic PPMs with a ≤ 2 PDAH daily average were included in this study. Patients were randomized to Usual Care (UC, N = 6) or a Physical Activity Counseling Intervention (PACI, N = 7) groups. Step count and PDAH data were obtained at baseline, following a 12-week intervention, then 12 weeks after intervention completion. Data were analyzed using independent t-tests, Pearson's r, chi-square, and general linear models for repeated measures.

RESULTS

PDAH significantly differed by time point for all subject combined (P = 0.01) but not by study group. Subjects with baseline gait speeds of > 0.8 m/sec were responsible for the increases in PDAH observed. Step counts did not differ over time in the entire cohort or by study group. Step count and PDAH significantly correlated at baseline (r = 0.60, P = 0.03). This correlation disappeared by week 12.

CONCLUSION(S)

PDAH can be used to monitor PA and PA interventions and may be superior to hip-worn pedometers in detecting activity. A significant increase in PA, regardless of treatment group, suggests that patient awareness of the ability to monitor PA through a PPM increases PA in these patients, particularly in patients with gait speeds of < 0.8 m/sec.

TRIAL REGISTRATION

ClincalTrials.gov NCT03052829. Date of Registration: 2/14/2017.

Physical Activity in Adults With Wearable Cardioverter Defibrillators in the Post-Myocardial Infarction Period

PURPOSE

Wearable cardioverter defibrillators (WCDs) provide lifesaving defibrillation and are equipped with accelerometers, capable of providing information on patient wear time and physical activity (PA). The purpose of this study was to report on patient PA while wearing a WCD.

METHODS

This study derived data from the WCD vendor in patients prescribed WCD post-myocardial infarction (MI) with left ventricular ejection fraction ≤35% in 2016. Using the device accelerometer, the relationship between wear time and PA was examined in a sample of consistent wearers of the WCD. Demographic variables, including sex and age, were examined for impact on wear time and PA. Changes in PA over time were also examined.

RESULTS

A total of 1952 patients (71% male) with a median age of 63 yr were included. Descriptive analyses indicated that overall median wear time was 23.8 hr/d; PA was 5568 steps/d. Significant differences in PA over time were identified, with median steps increasing by 67% from the first week of wear to the last week of wear. Patient age and wear time significantly predicted PA; patient age also significantly predicted patient wear time. There were significant differences in median hours of wear time, as well as median steps, based on sex.

CONCLUSIONS

PA in adults early after hospital discharge is modest and improves over the course of the 90-d WCD prescription in regular wearers. Improved health status may account for this change. The WCD accelerometer may have value in future clinical care and research by providing a window into daily patient PA levels via remote monitoring.