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Figure 1 Cumulative probability of first appropriate defibrillator therapy for ventricular tachycardia (VT) or ventricular fibrillation (VF) in patients with QT variability (QTVN) in the highest quartile versus lower three quartiles for QT variability index (QTVI) (top panel) and QTVN (bottom panel). P value from log-rank statistics. ICD = implantable cardioverter defibrillator.