A Cumulative Electrical Risk Score Is Associated with Appropriate ICD Therapy in Primary-Prevention Patients with Reduced Ejection Fraction: A Single-Center Retrospective Study

Figures

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  Figure 1. Patient selection flow chart.

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  Figure 2. Schematic representation of the eight electrocardiographic components of the electrical risk score (ERS) on a representative surface ECG tracing. The components include heart rate (>75 bpm), QRS duration (>110 ms), frontal QRS-T angle (>90°), left ventricular hypertrophy (Sokolow-Lyon or Cornell criteria), delayed intrinsicoid deflection (≥50 ms in leads V5–V6), delayed QRS transition (at or after V5), prolonged corrected QT interval (QTc; Bazett > 450 ms in men, >460 ms in women), and prolonged Tpeak–Tend (Tp-e) interval (>89 ms). Each component present contributes one point to the cumulative ERS (range 0–8). Dashed lines indicate the start or end boundaries of the reference points used for measurement. In the vector diagram, blue lines correspond to the measurement range for the criterion indicated in the right-hand text box on the same row, and green lines correspond to the measurement range for the criterion indicated in the left-hand text box on the same row. The green circle marks SV1; the blue circle indicates that QRS transition occurs at V6.

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  Figure 3. Receiver operating characteristic (ROC) curve for the electrical risk score in discriminating patients with appropriate ICD therapy (AUC = 0.795).

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  Figure 4. Calibration plot of the multivariable predictive model for appropriate ICD therapy. Additionally, the Hosmer–Lemeshow goodness-of-fit test and the Brier score were used as supplementary calibration measures. The dashed line represents perfect calibration (predicted probability equals observed proportion); the solid line represents the observed calibration of the model across risk deciles. The model showed excellent calibration (Hosmer–Lemeshow χ2 = 5.01, df = 8, p = 0.757; calibration slope = 1.00; Brier score = 0.162, optimism-corrected Brier score = 0.176).