Baseline Prolonged PR Interval and Outcome of Cardiac Resynchronization Therapy: A Systematic Review and Meta-analysis

Abstract

BackgroundRecent studies suggest that baseline prolonged PR interval is associated with worse outcome in cardiac resynchronization therapy (CRT). However, a systematic review and meta-analysis of the literature have not been made.ObjectiveTo assess the association between baseline prolonged PR interval and adverse outcomes of CRT by a systematic review of the literature and a meta-analysis.MethodsWe comprehensively searched the databases of MEDLINE and EMBASE from inception to March 2017. The included studies were published prospective or retrospective cohort studies that compared all-cause mortality, HF hospitalization, and composite outcome of CRT with baseline prolonged PR (> 200 msec) versus normal PR interval. Data from each study were combined using the random-effects, generic inverse variance method of DerSimonian and Laird to calculate the risk ratios and 95% confidence intervals.ResultsSix studies from January 1991 to May 2017 were included in this meta-analysis. All-cause mortality rate is available in four studies involving 17,432 normal PR and 4,278 prolonged PR. Heart failure hospitalization is available in two studies involving 16,152 normal PR and 3,031 prolonged PR. Composite outcome is available in four studies involving 17,001 normal PR and 3,866 prolonged PR. Prolonged PR interval was associated with increased risk of all-cause mortality (pooled risk ratio = 1.34, 95 % confidence interval: 1.08-1.67, p < 0.01, I2= 57.0%), heart failure hospitalization (pooled risk ratio = 1.30, 95 % confidence interval: 1.16-1.45, p < 0.01, I2= 6.6%) and composite outcome (pooled risk ratio = 1.21, 95% confidence interval: 1.13-1.30, p < 0.01, I2= 0%).ConclusionsOur systematic review and meta-analysis support the hypothesis that baseline prolonged PR interval is a predictor of all-cause mortality, heart failure hospitalization, and composite outcome in CRT patients.

Prolonged PR Interval and Outcome in Cardiac Resynchronization Therapy

“…We appreciate the author’s comments on our original article “Baseline Prolonged PR Interval and Outcome of Cardiac Resynchronization Therapy: A Systematic Review and Meta-analysis”. 1 We agree with the authors that the effect of PR interval in cardiac resynchronization therapy (CRT) population is unknown, and therefore we conducted a systematic review and meta-analysis on this topic.…”

“…However, to evaluate the effect of Friedman et al., 2 we performed a sensitivity analysis by excluding one study at a time which is shown in Supplementary Document 2 in the original article. 1 After excluding Friedman et al, 2 there was no significant change of the risk ratio of composite outcome (risk ratio = 1.19, 95% confidence interval: 1.04-1.36), all-cause mortality (risk ratio=1.53, 95% confidence interval: 1.23-1.91), and heart failure hospitalization (risk ratio = 1.6, 95% confidence interval: 1.06-2.42). 1 The meta-analysis pooled result still has a statistically significant risk ratio even if we exclude the study by Friedman et al 2 Therefore, a prolonged PR interval still predicts the outcomes of CRT regardless of the results of the study by Friedman et al 2…”

“…We read the article “Baseline Prolonged PR Interval and Outcome of Cardiac Resynchronization Therapy: A Systematic Review and Meta-analysis” by Rattanawong et al. 1 with great interest. The authors investigated the effect of prolonged PR interval on composite outcome among patients who received cardio resynchronized therapy.…”

“…The study by Lin et al 4 was excluded from our systematic review and meta-analysis due to an inappropriate comparison as demonstrated in Figure 1 of our original article. 1 Their objective is to compare the outcomes between CRT and optimal pharmacologic therapy stratified by PR interval. Our meta-analysis compared the outcome of prolonged PR interval versus normal PR interval only in CRT patients.…”

Can We Consider PR Interval to Screen Patients for Cardiac Resynchronization Therapy?

“…The electrocardiogram remains an important tool for selecting CRT candidates, and new parameters, such as the PR interval, are interesting to discriminate the prognosis in this population. On this issue, we have a meta-analysis study 2 concluding that the presence of prolonged PR interval is a marker of poor prognosis at baseline.…”