Abstract
IntroductionThe utility of accelerometer‐based activity data to identify patients at risk of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) has not previously been investigated. The aim of the current study was to determine whether physical activity is associated with manifesting spontaneous sustained VT/VF requiring emergent defibrillation in patients with an ejection fraction of ≤35%.MethodsPatients consecutively prescribed a wearable cardioverter defibrillator (WCD) from April 2015 to May 2018 were included. Shock data and 4 weeks of physical activity data, beginning with the first week of WCD wear, were analyzed.ResultsBased on the ROC curve outcome generated from 4057 patients, average daily step count during the first week accurately predicted those patients with sustained VT/VF compared to those without (shocked (n = 81) vs nonshocked (n = 3976) area under the curve, c‐index = 0.71, 95% CI = 0.65‐0.77, P < .001). An average cutoff of 3637 daily steps during week 1 separated the groups. Patients who averaged fewer than 3637 steps per day during the first week of WCD use were 4.3 times more likely to experience a shock than those who walked more than 3637 steps per day (OR = 4.29, 95% CI = 2.58‐7.15, P < .001).DiscussionAverage daily step counts are lower in WCD patients who manifest spontaneous VT/VF. Whether these findings represent a causal or correlational relationship, future studies to encourage a minimum daily step count in high‐risk patients may impact the incidence of sustained VT/VF.
Highlights
The utility of accelerometer-based activity data to identify patients at risk of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) has not previously been investigated
A total of 5528 patients were screened, 1471 patients were excluded for incomplete data (n = 97), not meeting minimum age (n = 15) or wearable cardioverter defibrillator (WCD) hours of wear requirements (n = 677), withdrawn WCD (n = 630), or if they died of unknown death during the study period (n = 52)
The present study suggests reduced activity may be a useful marker to identify patients at increased risk of sustained VT/VF, further adding to sudden cardiac death risk stratification beyond left ventricular ejection fraction
Summary
Accelerometer-based activity was associated with the risk of atrial arrhythmias.[9] Patients who were active for less than 3.5 hours per day were at a higher risk for subclinical high-rate atrial fibrillation lasting for 6 minutes or longer. These studies demonstrate the utility of physical activity as a mechanism to identify patients at risk for cardiac events. Receiver operating characteristic (ROC) curves were constructed to determine the optimal cutoff for predicting group membership (shocked vs nonshocked) using step count during week 1. All analyses were performed using SPSS version 25 (IBM SPSS Statistics, IBM Corporation, Armonk, NY)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
