title: Incidence and predictors of pacemaker dysfunction with unipolar ventricular lead configuration. Can we identify patients who benefit from bipolar electrodes?
abstract: Unipolar ventricular leads were implanted in a considerable percentage of pacemaker recipients. There is little information on incidence and risk factors for unipolar pacemaker dysfunction using modern lead designs. Included in a cross-sectional analysis were 682 patients who fulfilled the following criteria: chronically implanted bipolar ventricular leads (> 1 year), intraoperative stimulation threshold < 1.0 V/0.5 ms, and potential amplitude > 6 mV. Incidences of chest wall stimulation (CWS) at an output of twice the amplitude threshold and of myopotential oversensing (MPO) at a sensitivity of half the sensing threshold were assessed. Energy (0.60 [0.72] vs 0.63 [0.81] microJ) and sensing thresholds (8.31 [3.18] mV vs 8.47 [3.47] mV) did not differ between uni- and bipolar modes. While all pacemakers worked properly during bipolar configuration, malfunctions were observed in 5.9% of patients during unipolar configuration (CWS = 1.9%, MPO = 4.2%). Patient age > 76 years (hazard ratio HR 8.2; P < 0.001), heart failure > or = NYHA Class II (HR 3.8; P < 0.001), and an antiarrhythmic therapy with Class I or III drugs (HR 3.3; P = 0.002) were independently associated with the occurrence of unipolar pacemaker dysfunction. Use of steroid-eluting leads reduced the probability of pacemaker dysfunction (HR 0.45; P = 0.03). Risk factors for unipolar ventricular pacemaker malfunction were higher age, heart failure, and antiarrhythmic drug therapy. Particularly in these patients, use of bipolar ventricular leads is beneficial.
authors.affiliation: Medical University of Lübeck, Department of Internal Medicine II, Lübeck, Germany. uwe.wiegand@medinf.mu-luebeck.de
authors.forename: U K
authors.initials: UK
authors.lastname: Wiegand
authors.forename: F
authors.initials: F
authors.lastname: Bode
authors.forename: H
authors.initials: H
authors.lastname: Bonnemeier
authors.forename: R
authors.initials: R
authors.lastname: Tölg
authors.forename: W
authors.initials: W
authors.lastname: Peters
authors.forename: H A
authors.initials: HA
authors.lastname: Katus
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004562:Electrocardiography; D004567:Electrodes, Implanted; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D018570:Risk Assessment; D012815:Signal Processing, Computer-Assisted; D012984:Software