No abstract

Introduction: Late gadolinium enhancement on cardiac magnetic resonance imaging (LGE-CMR) has been shown to predict adverse cardiovascular outcomes, especially ventricular arrhythmic events. Hypothesis: A few studies, limited by small sample size, have examined the relationship between myocardial scar and cardiac resynchronization therapy (CRT) response. We performed a meta-analysis to determine whether scar identified on LGE predicts response to CRT in cardiomyopathy. Methods: We searched PubMed and Embase for clinical trials reporting CRT response based on scar determined by LGE -CMR. Primary outcome was defined as improvement in NYHA class or echocardiographic parameters (not limited to but including dP/dT, radial strain and reduction of LV end systolic volume). Random effects model was used to pool the data across the studies. Results: After screening 1876 articles, we identified 14 clinical trials that met inclusion criteria. A total of 984 patients were included in the analysis. There was no significant heterogeneity across the studies (I 2 =30%, p= 0.13). Presence of scar on LGE-CMR decreased CRT response by 39% (RR: 0.61 (95% CI 0.53 - 0.71; p<0.001). Exclusion sensitivity analysis did not change the effect size. Pooled analysis of studies reporting only ischemic cardiomyopathy revealed that any myocardial scar reduced CRT response by 38% (RR: 0.62 (0.44 - 0.86; p=0.004). Conclusions: The presence of any myocardial scar detected by LGE predicts sub-optimal response to CRT in cardiomyopathy. This shows that identification of scar using LGE- CMR can be used as an important risk stratification tool for CRT response.