New Onset of Pacemaker Dependency After Permanent Pacemaker Implantation

Abstract

Pacemaker dependency has dangerous consequences under conditions of electromagnetic interference, unrecognized lead dysfunction, and battery depletion, and has been associated with cardiovascular and overall mortality. The aim of this study was to examine the incidence of new onset of pacemaker dependency during long-term follow-up after pacing system implantation. The study included 518 patients (mean age 72.9 +/- 10.4 years) who presented with intrinsic rhythms at the time of implantation. Indications for pacing were sick sinus syndrome (SSS) in 275 (53%) patients, AV block in 209 (40%), and AF with bradycardia in 34 (7%) patients. The mean follow-up was 3.7 +/- 2.7 years (range 1-17). Pacemaker dependency was defined as the absence of an intrinsic rhythm during backup pacing at 30 beats/min for 30 seconds. New onset of pacemaker dependency was observed in 23 (4.4%) of the 518 patients at a mean of 3.1 +/- 2.7 years of follow-up. Pacing indications were SSS in 6 (2.2%) of 275 patients, AV block in 15 (7.2%) of 209, and AF with bradycardia in 2 (5.9%) of 34. Patients with AV block had a significantly higher incidence of pacemaker dependency than patients with SSS (odds ratio 3.51; 95% CI 1.3 to 9.3; P = 0.012). The average annual rate of new pacemaker dependency was 1.6% during an 8-year follow-up. The incidence of new onset of pacemaker dependency varied among pacing indications, and was significantly higher in patients with AV block than patients with SSS.

Long‐term Intrinsic Rhythm Evaluation in Dogs with Atrioventricular Block

“…In our study, PM dependency was found in 43.5% of the cases, similar to what has been reported in the human literature, where the time of onset is approximately 3 years …”

“…[45][46][47] In our study, PM dependency was found in 43.5% of the cases, similar to what has been reported in the human literature, where the time of onset is approximately 3 years. 24,26,48 Limitations of this study include its retrospective nature, which influenced particularly the timing of re-evaluation: T1 and T2 were homogeneous whereas T3 and T4 had wider CI. Intrinsic rhythm was evaluated during a limited time frame, and for this reason paroxysmal AVB could not be completely ruled out.…”

“…During telemetric ECG interrogation, pacing was set at 30 bpm for 30 seconds and IR was defined as the underlying cardiac rhythm recorded with a ventricular rate slower than the minimum pacing cycle length set. In case of lack of occurrence of IR, the dog was defined as “PM dependent” . The IR with a ventricular rate faster than the minimum pacing cycle length set was analyzed for the entire duration of the telemetric interrogation.…”

“…In case of lack of occurrence of IR, the dog was defined as "PM dependent". 24 The IR with a ventricular rate faster than the minimum pacing cycle length set was analyzed for the entire duration of the telemetric interrogation. Based on long-term IR evaluation, we classified the dogs in 3 groups according to the presence or absence of changes in AV conduction over time: unchanged, progressed, and regressed.…”

Factors predicting persistence of AV nodal block in post‐TAVR patients following permanent pacemaker implantation

“…Standard electrocardiography was assessed in the VVI mode with a backup frequency of 30 beats/minute. Patients were defined as pacemaker dependent if the intrinsic ventricular rate was less than 30 beats/minute over 30 s, consistent with previous studies …”