Association between patient activity and long-term cardiac death in patients with implantable cardioverter-defibrillators and cardiac resynchronization therapy defibrillators

Abstract

Background Patient activity (PA) has been demonstrated to predict all-cause mortality. However, the association between PA and cardiac death is unclear. Aims The aims of this study were to determine whether PA can predict cardiac death and what is the cut-off of PA to discriminate cardiac death, as well as the mechanism underlying the relationship between PA and survival in patients with home monitoring. Methods This study retrospectively analysed clinical and implantable cardioverter-defibrillator/cardiac resynchronization therapy defibrillator device data in 845 patients. Data regarding PA and PP variability during the first 30-60 days of home monitoring were collected, and mean values were calculated. The primary endpoint was cardiac death, and the secondary endpoint was all-cause mortality. Results The mean PA percentage was 11 ± 5.8%. Based on receiver operating characteristic curve analysis, we determined that a PA cut-off value of 7.84% (113 min) can predict cardiac death. During a mean follow-up period of 31.1 ± 12.9 months (ranging from three to 60 months), PA ≤ 7.84% was associated with increased risks of cardiac death in an unadjusted analysis; after adjusting in a multivariate Cox model, the relationship remained significant between PA≤7.84% and cardiac death (hazard ratio = 3.644, 95% confidence interval = 2.424-5.477, p < 0.001). Moreover, a significant correlation was observed between PA and PP variability ( r = 0.601, p < 0.001). Conclusions A baseline PA ≤ 7.84% was associated with a higher risk of cardiac death in patients who have survived more than three months after implantable cardioverter-defibrillator/cardiac resynchronization therapy defibrillator implantation. PA had a sizable effect on heart rate variability, reflecting autonomic function.

Measuring Physical Activity With Implanted Cardiac Devices: A Systematic Review

“…One multicenter retrospective cohort study of patients, however, found the association between “low D‐PA” (<30 min/d) and HF hospitalization to be nonsignificant in both unadjusted and adjusted models . This discrepant finding may reflect the different activity threshold used to define “low activity” in this study, which was considerably lower than the thresholds used in the other studies (<60–<113 min/d) . These data highlight an important shortcoming of data‐driven categorization of continuous variables and support the need for evidence‐based clinical thresholds for D‐PA.…”

“…One study of patients with pacemakers and preserved left ventricular function showed that all‐cause mortality increased as daily D‐PA decreased and that patients with lower D‐PA at baseline (<1 hour of activity per day) had a 7.4‐fold elevated mortality risk at follow‐up, compared with those who were more active (>3 h/d). Early activity (average activity over the first month after implantation) was also found to be inversely associated with all‐cause mortality and cardiac morality . Although these data are suggestive, they are observational, and thus D‐PA may have served as a marker for unmeasured factors contributing to mortality risk.…”

“…D‐PA data are increasingly being used to understand patterns of activity engagement after ICD implantation; however, investigators have varied in the approach taken to calculate the baseline level of D‐PA, making it difficult to compare findings across studies. In some studies, baseline is defined as average activity over a period of several days, 1 to 2 weeks after CIED implantation, to account for procedural recovery time; in other studies, baseline is defined as average activity over 7 to 30 days, 1 to 2 months after implantation . Despite this variation in approach, D‐PA at baseline is consistently low across studies (<3 hours of total activity per day), regardless of device manufacturer or sample characteristics .…”

“…The association between D‐PA and mortality has been a focus of considerable research. Seven studies examined the relationship between D‐PA and all‐cause mortality, with one including both all‐cause and cardiac mortality . Of these studies, all reported a significant inverse association between D‐PA and all‐cause mortality in unadjusted and adjusted models.…”

“…Of these studies, most have found that older adults, women, and those who are more frail engage in less daily activity than patients who are younger, men, and less frail . Comorbidities, such as AF, diabetes mellitus, peripheral artery disease, stroke, and diuretic use at baseline, have also been associated with lower levels of D‐PA in the months after CIED implantation . In contrast, findings on the relationship between activity and New York Heart Association functional class, left ventricular ejection fraction (%), device type, and ischemic cause have been inconsistent .…”