Association Between a Prolonged PR Interval and Outcomes of Cardiac Resynchronization Therapy

Abstract

BACKGROUND A prolonged PR interval is common among cardiac resynchronization therapy (CRT) candidates; however, the association between PR interval and outcomes is unclear, and the data are conflicting. METHODS We conducted inverse probability weighted analyses of 26 451 CRT-eligible (ejection fraction ≤35, QRS ≥120 ms) patients from the National Cardiovascular Data Registry ICD Registry to assess the association between a prolonged PR interval (≥230 ms), 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 versus ICD among patients when stratified by PR interval. Using Medicare claims data, we followed up with patients up to 5 years for incident heart failure hospitalization or death. RESULTS Patients with a PR≥230 ms (15%; n=4035) were older and had more comorbidities, including coronary artery disease, atrial arrhythmias, diabetes mellitus, and chronic kidney disease. After risk adjustment, a PR≥230 ms (versus PR<230 ms) was associated with increased risk of heart failure hospitalization or death among CRT-D (hazard ratio, 1.23; 95% confidence interval, 1.14–1.31; P<0.001) but not ICD recipients (hazard ratio, 1.08; 95% confidence interval, 0.97–1.20; P=0.17) (Pinteraction=0.043). CRT-D (versus ICD) was associated with lower rates of heart failure hospitalization or death among patients with PR<230 ms (hazard ratio, 0.79; 95% confidence interval, 0.73–0.85; P<0.001) but not PR≥230 ms (hazard ratio, 1.01; 95% confidence interval, 0.87–1.17; P=0.90) (Pinteraction=0.0025). CONCLUSIONS A PR≥230 ms is associated with increased rates of heart failure hospitalization or death among CRT-D patients. The real-world comparative effectiveness of CRT-D (versus ICD) is significantly less among patients with a PR≥230 ms in comparison with patients with a PR<230 ms.

Left ventricular‐only pacing in heart failure patients with normal atrioventricular conduction improves global function and left ventricular regional mechanics compared with biventricular pacing: an adaptive cardiac resynchronization therapy sub‐study

“…Since we did see trends for better response rates with aCRT, it is likely that our inclusion of only patients with normal AV intervals resulted in group sizes too small to detect differences. Additionally, patients with normal AV conduction may have been healthier at baseline, as a previous large registry study demonstrated that patients with pre‐CRT PR intervals of ≥230 ms had a greater risk of HF hospitalization or death than those with short PR intervals . Thus patients with normal AV conduction in our study could be less likely to exhibit improvements.…”

Sequential His bundle and left ventricular pacing for cardiac resynchronization

“…27 Finally, prolonged atrioventricular conduction which occurs in 15%-50% of patients undergoing CRT may limit the use of adaptive atrioventricular delay programming. 30,31 The use of HBP has the advantage of allowing for optimization of the atrioventricular interval in patients with atrioventricular conduction disease. The improvements in acute electrical resynchronization were also seen in the subgroup of patients who underwent atrioventricular nodal ablation for AF in whom fusion of intrinsic activation with biventricular pacing would not be possible.…”

Non‐invasively quantified changes in left ventricular activation predict outcomes in patients undergoing cardiac resynchronization therapy

“…[15][16][17][18] Subsequent analyses demonstrating patients with LBBB were more likely to benefit from CRT 3,19 (presumed due to greater extent of LV activation delay) 20 have underscored the importance of the electrical substrate. However, a significant minority of LBBB patients do not respond to CRT 19,21 and an important minority of non-LBBB patients do appear to benefit from CRT 22,23 although this remains controversial. Furthermore, it is increasingly recognized that optimal LV lead position [24][25][26] and device programming algorithms 27 affect CRT outcomes as they directly impact the activation wavefronts responsible for LV depolarization.…”