Zero-fluoroscopy catheter ablation of severe drug-resistant arrhythmia guided by Ensite NavX system during pregnancy: Two case reports and literature review

Abstract

Background: Cardiac arrhythmias can occur during pregnancy. Owing to radiation exposure and other uncertain risks for the mother and fetus, catheter ablation has rarely been performed and is often delayed until the postpartum period. We reported 2 pregnant women who were experiencing severe arrhythmias and were successfully ablated without fluoroscopic guidance. We also carried out a literature review of cases of pregnant women who underwent zero-fluoroscopy ablation.

Methods and results: One woman had drug-resistant and poorly tolerated frequent premature ventricular contraction (PVC) and ventricular tachycardia (VT). The other one had persistent and hardly terminated supraventricular tachycardia (SVT) via a right accessory pathway. The 2 patients were successfully underwent zero-fluoroscopy ablation guided by Ensite NavX system. The procedure time was 42 and 71 minutes, respectively.

Conclusion: Catheter ablation of SVT or PVC/VT in pregnant patients can be safely and effectively performed with a completely zero-fluoroscopy approach guided by the Ensite NavX system. In the case of a drug refractory, life-threatening arrhythmia during pregnancy, catheter ablation may be considered.

Figure 1

(A) Surface electrocardiograms show frequent premature ventricular complexes before radiofrequency catheter ablation. (B) Path and geometry-relevant structure during catheter insertion. The name of surface leads and AB electrodes were shown in the left panel of the figure. (C) Electrophysiology study was performed without X-ray exposure guided by the Ensite NavX system. Upper panel: The yellow dot denotes the His bundle; the lowest green dot marks the tip of AB placed at target site in the septum of the right ventricular outflow tract; the red dot denotes 2 sites where ablation was attempted for 10 seconds but failed (LAO, left anterior oblique view, RAO = right anterior oblique view). Lower panel: The local ventricular activation at the tip of AB is 33 milliseconds earlier than that at surface electrocardiography recordings; radiofrequency ablation at the upper green dot abolishes the ventricular premature beat and ventricular tachycardia; from the top down are the unipolar recordings from the ablation catheter (AB), surface lead I, II, III, avR, avL, avF, and V1 to V6, and the bipolar recordings from distal pair of the AB.

Figure 2

(A) Surface electrocardiograms show an evident delta wave due to an accessory pathway before radiofrequency catheter ablation. (B) Electrophysiology study was performed without X-ray exposure guided by the Ensite NavX system. Upper panel: The yellow dot denotes the His bundle; the green dot denotes the suspected location of 2 accessory pathways; the tip of tetrapolar catheter was placed near the His bundle to verify the right anatomic location after the tentative ablation and before the final ablation delivery (LAO, left anterior oblique view, RAO = right anterior oblique view). Lower panel: Surface electrocardiography recordings showed the occurrence of supraventricular tachycardia (SVT); the white arrow indicates the potential of the His bundle recorded by ablation catheter (AB). (C) Radiofrequency ablation at the upper green dot abolishes the accessory pathway. The name of surface leads, RV, and AB electrodes are shown in the left panel of the figure.