Physical Activity and Pacemaker Study

Overview

The benefits of regular physical activity are well-established. Furthermore, the investigators have previously shown that in a population of patients with implanted pacemakers, those who exercise more than 2 hours daily have improved survival compared with those who exercise less than 2 hours daily. In this study, the aim f the investigators is to determine whether the offering subjects with pacemakers who have low levels of physical activity at baseline counseling to increase physical activity levels is effective as measured by their implanted device as well as by an external pacemaker. The investigators seek to enroll about 30 patients into a 6-month 1:1 randomized interventional trial comparing the levels of physical activity in 2 groups, those who receive physical activity counseling versus usual care. The activity levels will be measured with external pedometers and with accelerometers embedded within the pacemaker device.

The benefits of habitual physical activity (PA, activities of at least moderate intensity defined as ≥ 3 metabolic equivalents (METs)) are well-recognized. Emerging information from large data sets strongly suggest high levels of sedentary behavior, defined as activities \<1.5 METs (equivalent to the amount of energy expended during seated activities such as computer work) increases the risk of diabetes, cardiovascular disease, and death, independent of the amount and intensity PA. The increased risk of sedentary behavior appears to be mediated at least in part by reduced insulin sensitivity, impaired lipid metabolism, increased vascular inflammation, and increased thrombotic tendencies. The internal accelerometer embedded in Medtronic pacemakers registers, stores, and reports total number of "active time" based on a threshold activity intensity level of approximately 70 steps/min (estimated to be \> 1.5 METs). This implanted accelerometer, combined with the regular follow-up required for appropriate care make individuals who have undergone Medtronic pacemaker implantation an ideal population in which to evaluate the impact of altering sedentary behavior on mortality and cardiovascular events. The hypotheses are as follows: 1. a 12 week intervention to increase moderate intensity physical activity delivered at the point of care in patients with pacemakers will result in parallel increases in active time as measured by the pacemaker and step count as measured by pedometer. 2. the increase in activity measured by both the metrics in hypothesis 1 will be greater than with usual care. Potential subjects who are interested in the study will have a screening visit to determine whether they meet the inclusion and exclusion criteria. Those who qualify and agree to participate will be randomized into either the Physical Activity Counseling arm (intervention arm) or the Patient Usual Care arm (control arm). Subjects in the interventional arm will be given a pedometer and physical activity counseling on a regular basis for 3 months. Physical activity data from their external pedometer will be collected every 2 weeks via phone calls. Accelerometry data from the implanted pacemaker will be collected from the subject's medical record as pacemaker interrogations are performed every 3 months as part of routine clinical care. After the initial 3 month interventional phase is complete, these subjects will be followed for another 3 months with collection of pedometer as well as accelerometer data as described above. Subjects in the control arm will be given pedometers for the week prior to pacemaker interrogation. These subjects will be called to report the number of steps they walked each day prior to the interrogation. Their accelerometry data will be captured through routine clinical pacemaker interrogations. The primary outcome is the physical activity level in each group as measured by the accelerometer at time 0, 3 months and 6 months. The secondary outcome is the step count in each group as measured by the pedometer at the same time points.