Abstract 16036: Right Ventricular Defibrillator Lead Sensing Threshold Decreases After Left Ventricular Assist Device Implant
Introduction: Left ventricular assist devices (LVADs) are increasingly offered to patients with advanced cardiomyopathy. Many LVAD recipients have implantable cardioverter-defibrillators (ICDs) for prevention of sudden cardiac death. Prior research has suggested that right ventricular (RV) lead parameters may be affected by LVAD placement. We sought to evaluate for any changes in RV lead parameters that could adversely influence arrhythmia detection after LVAD placement.
Methods: Patients who received a continuous-flow LVAD at the University of Chicago between 2008 and 2010 were considered for participation. A subgroup of patients with a previously implanted ICD was identified, and RV lead sensing and pacing parameters both pre- and post-LVAD implant were retrospectively examined. The Wilcoxon signed-rank test was used for all statistical analysis. A P value less than 0.05 was considered statistically significant.
Results: Eleven patients (7 male, 4 female) were included in the analysis; 9 (82%) had a non-ischemic cardiomyopathy. Age at time of LVAD implant was 53 +/- 11 years, and left ventricular ejection fraction was 21 +/- 5%. Mean RV sensing thresholds decreased from 13.1 +/- 6.3 millivolts (mV) pre-LVAD to 10.4 +/- 6.2 mV after LVAD implant (P=0.02). Mean RV capture thresholds increased from 1.0 +/- 1.1 microjoules (μ J) pre-LVAD to 1.8 +/- 2.7 μ J post-LVAD (P=0.06). Mean RV pacing impedance decreased from 486 +/- 88 ohms pre-LVAD to 452 +/- 89 ohms post-LVAD (P=0.06).
Conclusions: RV lead sensing thresholds decreased significantly after continuous-flow LVAD implant in patients with a previously implanted ICD. There was also a trend toward decreasing pacing impedance and increasing RV pacing threshold after LVAD implant. While the mean sensing threshold post-LVAD implant likely remained adequate for reliable detection of ventricular arrhythmias, formal ICD interrogation and regular follow-up post-LVAD is warranted. Defibrillation threshold testing with careful attention to arrhythmia sensing may be advisable in certain patients for whom the RV sensing threshold falls to marginal values. Further prospective studies are required to investigate more fully the influence of LVAD implantation on ICD function.
- © 2011 by American Heart Association, Inc.