Characteristics of Bipolar and Unipolar Electrograms at Optimal Ablation Sites for Ventricular Arrhythmias Originating Near the Left Ventricular Summit

Figures

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  Figure 1. Patients with structural heart disease, reentrant VAs, or insufficient electrogram quality/mapping data were excluded from the analysis, resulting in a final cohort of 78 patients with 80 idiopathic LV summit VAs. AIV indicates anterior interventricular vein; CAD, coronary artery disease; GCV, great cardiac vein; LV, left ventricular; PVC, premature ventricular complex; RVOT, right ventricular outflow tract; VA, ventricular arrhythmia; and VT, ventricular tachycardia.

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  Figure 2. Representative electrogram annotation and comparison of successful and unsuccessful mapping points. A, Electrogram annotation methodology and a representative example from a successful mapping point for a PVC originating from the vicinity of the LV summit. A unipolar QS morphology is observed. The blue dashed line marks the onset of the bipolar electrogram, while the white dashed line indicates the onset of the QRS complex. The orange dashed line and asterisk denote the time point of the maximal unipolar −dV/dT. The red dashed lines represent the onset and trough of the unipolar electrogram, whereas the yellow dashed line indicates the time point (20 ms) after the onset of the unipolar electrogram. Key measurements include LATBi (44 ms), LATUni (−11 ms), LATBi −LATUni (55 ms), unipolar voltage amplitude at 20 ms (0.12 mV), and unipolar descending limb interval (34 ms). B, Representative example from an unsuccessful mapping point for another PVC originating near the LV summit. The LATUni at the unsuccessful site was comparable with that at the successful site. However, bipolar activation occurred later, resulting in a shorter LATBi. This contrast illustrates the value of LATBi…

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  Figure 3. Receiver operating characteristic curve for LATBi in predicting successful ablation targets. The curve shows an area under the curve of 0.67, indicating moderate predictive value. AUC indicates area under the curve; and LATBi, bipolar local activation time.