Incidence and Predictors of Pacemaker Dysfunction with Unipolar Ventricular Lead Configuration. Can We Identify Patients Who Benefit from Bipolar Electrodes?

WIEGAND, U.K.H., et al. : Incidence and Predictors of Pacemaker Dysfunction with Unipolar Ventricular Lead Configuration. Can We Identify Patients Who Benefit from Bipolar Electrodes? 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] μJ) 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 ≥ 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.