Discrimination of sustained VT in structural heart disease using LGE-CMR and computational simulation: moving beyond LVEF

Figures

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  Figure 1. Study flow chart and clinical outcomes. The flowchart depicts the selection of patients with suspected SHD based on LGE-CMR findings and their subsequent classification by 6-month arrhythmic outcomes. LGE-CMR, late gadolinium enhancement cardiac magnetic resonance; VT, ventricular tachycardia; SCD, sudden cardiac death; ICD, implantable cardioverter-defibrillator; VA, ventricular arrhythmia; PVCs, premature ventricular contractions.

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  Figure 2. LGE–vTsim index for differentiating sustained VT events. (A) The ROC analysis of the novel LGE-VTsim index (pink, C-statistics = 0.816) and the conventional LVEF metric (teal curve, C-statistics = 0.730) in discriminating sustained VT events. Optimal cutoffs (determined by the Youden's index) are marked: 25.6 for LGE-VTsim and 50.4 for LVEF. (B) Calibration curve (with loess smoothing) of the LGE-VTsim index, illustrating the agreement between predicted probabilities of sustained VT and observed event frequencies. The dashed line represents perfect calibration (where predicted probability = observed frequency), and the shaded area denotes the 95% confidence interval reflecting estimation uncertainty. (C) Decision curve analysis comparing the net benefit of using the LGE-VTsim index (red line), LVEF (teal line), for predicting sustained VT, relative to a “None” strategy (horizontal black dashed line). The x-axis represents predicted probability thresholds, and the y-axis represents net benefit. ROC, receiver operating characteristic; LVEF, left ventricular ejection fraction; C-index, concordance index; LGE-VTsim index = 0.862× Grey Zone + 0.614 × Core Scar + 0.906× VT Inducibility…

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  Figure 3. Sustained VT risk discrimination based on LGE-VTsim index. This flowchart presents an exploratory stepwise framework for VT risk stratification in suspected SHD. LGE-CMR screening first divides patients: LGE-positive cases undergo digital twin reconstruction and VT simulation to derive an LGE-VTsim index (>25.6 indicating high risk), while LGE-negative cases are stratified by LVEF (≤35 indicating high risk as conventionally suggested). This integrated approach enhances risk recognition beyond LVEF alone. CMR, cardiac magnetic resonance; LGE, late gadolinium enhancement; LVEF, left ventricular ejection fraction; SHD, structural heart disease; VT, ventricular tachycardia.

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  Figure 4. Central Illustration. This study developed a hypothesis-generating parameter, named LGE-VTsim index, incorporating LGE-CMR for scar quantification, and virtual VT inducibility and circuits. the proposed method overcomes limitations of traditional LVEF-based risk assessment. LGE-CMR, late gadolinium enhancement cardiac magnetic resonance; VT, ventricular tachycardia; SCD, sudden cardiac death; SHD, structural heart disease; LVEF, left ventricular ejection fraction.