The Role of the Ratio of J-Point Elevation Magnitude and R-Wave Amplitude on the Same ECG Lead in the Risk Stratification of Subjects With Early Repolarization Pattern.

BackgroundJust as high-risk populations for cardiac arrest exist in patients with Brugada syndrome or long QT syndrome, high-risk and low-risk populations for cardiac arrest also exist in patients with early repolarization pattern (ERP). HypothesisElectrocardiographic (ECG) characteristics can aid the risk stratification of patients with ERP. MethodsElectrocardiographic parameters such as magnitude of J-point elevation and J/R ratio were measured. The magnitude of J-point elevation, leads with J points elevated, J/R ratio, morphology of the ST segment, and QT/QTc interval were used in comparative analysis in 2 groups: 57 patients with ERP and cardiac arrest (cardiac arrest group) and 100 patients with ERP but without cardiac arrest (control group). ResultsThere was no statistical difference in clinical characteristics of the 2 groups. The J/R ratio in the cardiac arrest group was significantly higher than in the control group (26.8%18.1% vs 16.3%+/- 10.3%, respectively; P < 0.001) and the proportion of horizontal/descending ST segments (70.2%) was significantly higher than in the control group (29.0%), but the proportion of ascending/upsloping ST segments (29.8%) was significantly lower than in the control group (71.0%; P < 0.001). Multivariate logistic regression revealed that higher J/R ratio and horizontal/descending ST segment were independently associated with increased risk of cardiac arrest in patients with ERP. Conclusions In patients with ERP and cardiac arrest, J/R ratios were relatively higher and mostly with horizontal/descending ST segments, suggesting that J/R ratio and ST-segment morphology may be used as indicators for risk stratification in patients with ERP.