Torsade de Pointes Due to QT Prolongation after Pulmonary Vein Isolation for Persistent Atrial Fibrillation

Figures

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  Figure 1.. (A) A 12-lead electrocardiogram acquired soon after electrical cardioversion 3 months before pulmonary vein isolation. The HR was 54 bpm. The raw QT interval was 487 ms, and the Fridericia formula [QTc=QT/ (RR 1/3)]-corrected QTc was 470 ms. (B) A 12-lead electrocardiogram showing atrial fibrillation before catheter ablation. The raw QT was 427 ms, and the Fridericia-corrected QTc was 449 ms. The raw QT was measured using the tangent method as an average of six or more beats.

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  Figure 2.. Three-dimensional computed tomography merged voltage map after pulmonary vein isolation. Each tag shows an ablation point.

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  Figure 3.. QT prolongation was observed two days after pulmonary vein isolation. The HR was 71 bpm. The raw QT was 540 ms, and the Fridericia-corrected QTc was 549 ms. T wave inversions were found in I, aVL, and V2. Torsade de pointes (TdP) occurred despite the normalization of serum Mg levels. TdP disappeared with the recurrence of atrial fibrillation.

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  Figure 4.. A 12-lead electrocardiogram was acquired on the third day after the procedure, showing atrial fibrillation. The raw QT was 362 ms, and the Fridericia-corrected QTc was 440 ms. QT prolongation and negative T waves were improved.