Does scar burden predict sudden cardiac death in patients with cardiac resynchronization therapy? - A Systematic Review and Meta-Analysis

Abstract

Abstract Background Based on latest guidelines, scar burden assessment may have a crucial role in appropriate device choice in cardiac resynchronization therapy (CRT), but no randomized controlled trials have been made yet.1 Scar burden is associated with a higher prevalence of ventricular arrhythmias (VA) and sudden cardiac death (SCD).2 Late gadolinium enhancement cardiovascular magnetic resonance (LGE-CMR) can accurately evaluate the extent of myocardial scar.3. Purpose Our aim is to investigate the association between scar burden and SCD risk in cardiac resynchronization therapy patients. Methods We performed a systematic literature search on MEDLINE using the PubMed, Embase, Scopus, and CENTRAL databases. Heart failure patients with reduced ejection fraction and CRT therapy were collected. The primary endpoint was sudden cardiac death events. Meta-analyses were performed using the META and DMETAR packages in R, using a random-effects model. The risk of bias was assessed using Quips tool and the quality of evidence was evaluated using the GRADE assessment. Results 18 eligible articles have been included in our study, with a total of 2917 patients, of whom 830, 1324, and 391 have been implanted with an ICD, CRT-D, CRT-P respectively. Altogether 59,05 % of the total population were LGE-CMR positive. The average proportion of appropriate ICD shock was 15,65 % per the total population during the median follow-up time of 39,45 months. Based on the univariant analysis of 14 articles, the cumulative hazard ratio of developing sudden cardiac death events, in the scar burden positive population compared to scar burden negative was 1,95 with CI: 1,29- 2,96 p<0,001. The multivariant analysis shows the HR of 1,88 with CI: 1,20- 2,93 p<0,001. There were 4 articles using the competing risk model which is considered to be the highest evidence level. Based on that analysis we found only a trend with a HR of 1,55 CI: 0,75-2,92. Calculating from the event numbers based on 8 eligible articles, the high scar burden group had 5.55 higher odds of getting SCD events. (OR: 5.55. CI 2,52-12,22 p<0,001). Conclusion In our meta-analysis, LGE-CMR was associated with a trend toward appropriate device therapy and can identify a subgroup of patients with an increased risk of life-threatening VA. Based on our results performing an MRI before device implantation might be important to select high-risk patients for SCD.Forest plot O.R.Forest plot uni. H.R.