Association between electrocardiographic QRS transition zone and mortality from all causes and cardiovascular diseases: A systematic review and meta-analysis

Aims: To investigate whether clockwise rotation (CWR) and counterclockwise rotation (CCWR) of electrocardiographic QRS transition zone is associated with mortality from all causes and cardiovascular diseases (CVD). Methods: Studies were identified from searching of PubMed, EMBASE and the reference lists of relevant papers. Summary multivariate-adjusted hazard ratios (HRs) and the corresponding 95% confidence intervals (CIs) and 95% prediction intervals (PIs) were computed through meta-analysis. Results: A total of five observational cohort studies fulfilled the inclusion criteria, which included 47,252 participants from the general population (8.8% CWR; 44.1% CCWR). Pooling data revealed that CWR was significantly associated with the increased risk of all-cause mortality (HR, 1.18; 95% CI: 1.12–1.24; 95% PI: 1.03–1.37) and CVD mortality (HR, 1.18; 95% CI: 1.08–1.29; 95% PI: 0.98–1.42) compared to NR pattern, with low heterogeneity among studies (P = 0.29, I² = 20%; P = 0.37; I² = 7%; respectively). However, CCWR was inversely associated with the risk of all-cause mortality (HR, 0.92; 95% CI: 0.89–0.95; 95% PI: 0.80–1.05) with low heterogeneity (P = 0.14; I² = 43%), while no significant association existed between CCWR and CVD mortality (HR, 0.89; 95% CI: 0.77–1.02; 95% PI: 0.53–1.48) with high heterogeneity (P < 0.01; I² = 78%). Conclusion: Our meta-analysis demonstrated CWR was positively associated with higher risk of mortality from all-cause and CVD, while CCWR was negatively associated with the risk of all-cause mortality and no significant association with CVD mortality. These findings suggested that QRS transition zone carries important prognostic value, more attention should be paid in clinical practice.