Association Between a Prolonged PR Interval and Outcomes of Cardiac Resynchronization Therapy: A Report from the National Cardiovascular Data Registry
Background—A prolonged PR interval is common among cardiac resynchronization therapy (CRT) candidates; however, the association between PR interval and outcomes is unclear, and data are conflicting.
Methods—We conducted inverse probability weighted (IPW) analyses of 26,451 CRT eligible (EF≤35, QRS≥120ms) patients from the National Cardiovascular Data Registry ICD Registry to assess the association between a prolonged PR interval (≥230ms), receipt of CRT with defibrillator (CRT-D) versus implantable cardioverter defibrillator (ICD), and outcomes.. We first tested the association between a prolonged PR interval and outcomes among patients stratified by device type. Next, we performed a comparative effectiveness analysis of CRT-D vs. ICD among patients when stratified by PR interval. Patients were followed up to 5 years for incident heart failure (HF) hospitalization or death based on Medicare claims data.
Results—Patients with a PR≥230ms (15%; n=4,035) were older and had more comorbidities including coronary artery disease, atrial arrhythmias, diabetes, and chronic kidney disease. After risk-adjustment, a PR≥230ms (vs. PR <230ms) was associated with increased risk of HF hospitalization or death among CRT-D (HR 1.23, CI 1.14-1.31, p<0.001) but not ICD recipients (HR 1.08, CI 0.97-1.20, p=0.17)(pinteraction=0.043). CRT-D (vs. ICD) was associated with lower rates of HF hospitalization or death among patients with PR<230ms (HR 0.79, CI 0.73-0.85, p<0.001) but not PR≥230ms (HR 1.01, CI 0.87-1.17, p=0.90)(pinteraction=0.0025).
Conclusions—A PR≥230ms is associated with increased rates of HF hospitalization or death among CRT-D patients. The real world comparative effectiveness of CRT-D (vs ICD) is significantly less among patients with a PR≥230ms compared to patients with a PR<230ms.
- Received April 8, 2016.
- Revision received September 14, 2016.
- Accepted September 26, 2016.