Periodic Repolarization Dynamics (PRD) identifies patients who profit from ICD implantation, A meta-analysis of the predictive value of PRD
Authors: Sams L E , Klemm M , Woerndl M , Bachinger L , Villegas Sierra L E , Massberg S , Rizas K D 
Published: November 2023

Abstract

Background
Periodic repolarization dynamics (PRD) is an electrocardiographic marker that quantifies sympathetic-activity associated instabilities of cardiac repolarization. PRD is a strong predictor of mortality in patients with ischemic (ICM) and non-ischemic cardiomyopathy (NICM) and has been proposed to identify patients who benefit from prophylactic ICD implantation.

Purpose
To conduct a systematic review and meta-analysis concerning the prognostic value of PRD for predicting all-cause mortality in relation to prophylactic ICD-implantation.

Methods
This meta-analysis follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. A total of 25 articles were screened and 7 randomized and non-randomized controlled trials identified. Finally, a total of 5 could be included in the analysis (Fig.1). Patients were stratified into patients with or without prophylactic ICD-implantation (Fig.2). The prognostic value of PRD for predicting all-cause mortality was extracted from published data as hazard ratio (HR) per 1 deg2 increase in PRD. We used inverse-variance-weighted average meta-analysis to calculate fixed and random effect models to estimate the overall predictive value of PRD in both groups. The interaction between PRD and prophylactic ICD-implantation for predicting mortality was calculated using meta-regression analysis. All analyses were performed using CRAN R v. 4.1.2 and the meta-package v 5.2.0.

Results
We included 4,338 patients in this meta-analysis, of whom 3,167 (73%) suffered from ICM and 1,171 (27%) from NICM. 1,906 (44%) patients were treated with an ICD. During an estimated mean follow-up time of 3.2 years, 604 (14%) patients died. Fig. 2 (left) shows patients without ICD treatment (N = 2,432, 56%). In these patients, a 1 deg2 increase in PRD was significantly associated with an overall 8% increase in mortality (fixed effect HR 1.08; 95% CI 1.06-1.10; p&lt; 0.001, random effect HR 1.08; 95% CI 1.06-1.11; p &lt; 0.001). Fig. 2 (right) displays the prognostic value of PRD in patients treated by ICD (N = 1,906). In these patients, a 1 deg2 increase in PRD was significantly associated with an overall 3% increase in mortality (fixed-effect HR 1.03; 95% CI 1.01-1.05; p&lt; 0.001, random-effect HR 1.03; 95% CI 1.00-1.06; p &lt; 0.001). An increase in PRD was not significantly associated with an increase in mortality in patients from the EU-CERT-ICD and DANISH trial. There was a significant interaction between PRD and prophylactic ICD-implantation for predicting all-cause mortality (p = 0.008).

Conclusion
In patients with ICM and NICM, PRD is a strong predictor of all-cause mortality in patients with and without prophylactic ICD. The significant interaction between PRD and prophylactic ICD-implantation most probably implies a reduction in the risk identified by PRD through ICD implantation. Consequently, PRD could prove a useful tool for identifying patients that might benefit from ICD treatment.Figure 1Figure 2