Left ventricular pacing threshold and outcome in MADIT-CRT
Luis A Pires1, Scott McNitt2, Scott Solomon3
1the Heart Rhythm Center and Cardiovascular Medicine, St. John Hospital and Medical Center, Detroit, Michigan, USA.
Journal of Cardiovascular Electrophysiology
|May 3, 2014
Summary
High intraoperative left ventricular pacing threshold (LVPT) predicts poorer outcomes in cardiac resynchronization therapy (CRT). Increased LVPT is linked to reduced reverse remodeling and higher risks of heart failure or death following CRT-D implantation.
Area of Science:
- Cardiology
- Medical Devices
- Clinical Trials
Background:
- High left ventricular pacing threshold (LVPT) may indicate myocardial scarring, a predictor of poor outcomes in cardiac resynchronization therapy (CRT).
- Intraoperative LVPT is hypothesized to predict echocardiographic and clinical responses to CRT.
Purpose of the Study:
- To investigate the relationship between intraoperative LVPT and patient response to CRT-D.
- To determine if LVPT can predict echocardiographic and clinical outcomes in CRT patients.
Main Methods:
- Analysis of 975 patients from the MADIT-CRT trial (CRT-D arm).
- Multivariate regression to assess LVPT's association with LV end-systolic volume (LVESV) and left atrial volume (LAV) reduction.
- Cox proportional hazards analysis for heart failure (HF) events/death and all-cause death.
Main Results:
- Increasing LVPT inversely correlated with reduced LVESV (P=0.02) and LAV (P<0.01).
- Patients with highest quartile LVPT (>1.8 V) showed less reverse LV remodeling (OR 0.56, P=0.02).
- Higher LVPT was associated with increased risk of HF/death (13%, P=0.06) and death alone (22%, P=0.03) per 1-volt increase.
Conclusions:
- High intraoperative LVPT is significantly associated with diminished echocardiographic and clinical response to CRT-D.
- LVPT serves as a valuable predictor of CRT efficacy and patient outcomes.
