Step-by-Step Approach to Phrenic Nerve Displacement

Abstract

Phrenic nerve injury, though rare, can be a serious complication of catheter ablation leading to significant morbidity. The close proximity of the phrenic nerve to the site of origin of arrhythmias may also impact the success of catheter ablation. When the phrenic nerve is near the optimal site of ablation, several techniques have been proposed to create separation between the nerve and the epicardium, including the introduction of fluid, gas, and balloons. In this article, we present a step-by-step approach to phrenic nerve displacement to facilitate ablation, including a review of phrenic nerve anatomy, localization techniques, procedural strategies, and necessary equipment.

Keywords: clinical: catheter ablation—atrial fibrillation; clinical: catheter ablation—atrial tachycardia; clinical: catheter ablation—ventricular tachycardia.

Figure 1

Cadaver dissection demonstrating phrenic nerve anatomy with intact pericardium. (A) Right phrenic nerve from right lateral direction. (B) Left phrenic nerve from left lateral direction. Reproduced from Mori and Shivkumar [11]. Copyright Cardiotext Publishing.

Figure 2

Cadaver dissection of right and left phrenic nerves (yellow and red arrows, respectively). (A) Intact fibrous pericardial sac. (B) Partial removal of fibrous pericardium and lungs. Ao = aorta, LV = left ventricle, RA = right atrium, RV = right ventricle. Reproduced from Sánchez‐Quintana et al. [12]. Copyright John Wiley and Sons.

Figure 3

CT of the left phrenic nerve transversing the left lateral ventricle. Blue arrow demonstrating the left phrenic nerve.

Figure 4

Delineation of the right phrenic nerve course using CT scan (white arrow). (A) Axial slide at the level of the right superior pulmonary vein. (B) Coronal slice. SVC = superior vena cava. Reproduced from Squara et al. [15]. Copyright CC BY 4.0.

Figure 5

Right phrenic nerve (white arrows) identified with ICE from the RA (A and B). Reproduced from Liu et al. [16]. Copyright CC BY‐NC 4.0.

Figure 6

Phrenic nerve capture sites displayed over anatomical left ventricular maps. (A) Yellow dots notes denote phrenic capture. (B) White dots denote phrenic capture.

Figure 7

Anatomic map with phrenic nerve capture sites denoted with black dots. (A) RAO view of the RA and LA. (B) RAO view of the LA.