Movement of the esophagus during left atrial catheter ablation for atrial fibrillation.

OBJECTIVES: The aim of this study was to describe the extent of esophageal mobility that occurs during catheter ablation for atrial fibrillation under conscious sedation. BACKGROUND: Ablation along the posterior left atrium may cause an atrioesophageal fistula. One strategy for avoiding this risk is to not deliver radiofrequency energy at sites in contact with the esophagus. METHODS: In 51 consecutive patients with atrial fibrillation who underwent left atrial ablation under conscious sedation, digital cine-fluoroscopic imaging of the esophagus was performed in two views after ingestion of barium paste at the beginning and end of the ablation procedure. Movement of the esophagus was determined at the superior, mid-, and inferior parts of the posterior left atrium in reference to the spine. RESULTS: Mean esophageal movement was 2.0 +/- 0.8 cm (range = 0.3 to 3.8 cm) at the superior, 1.7 +/- 0.8 cm (range = 0.1 to 3.5 cm) at the mid-, and 2.1 +/- 1.2 cm (range = 0.1 to 4.5 cm) at the inferior levels. In 67% of the 51 patients, the esophagus shifted by > or =2 cm, and in 4% there was > or =4 cm of lateral movement. The mean change in esophageal luminal width was 5 +/- 7 mm (range = 0 to 36 mm) at the superior, 5 +/- 7 mm (range = 0 to 32 mm) at the mid-, and 6 +/- 7 mm (range = 0 to 21 mm) at the inferior levels of the posterior left atrium. CONCLUSIONS: The esophagus often is mobile and shifts sideways by > or=2 cm in a majority of patients undergoing catheter ablation for atrial fibrillation under conscious sedation. Therefore, real-time imaging of the esophagus may be helpful in reducing the risk of esophageal injury during radiofrequency ablation along the posterior left atrium.     

Esophageal imaging and strategies for avoiding injury during left atrial ablation for atrial fibrillation

BACKGROUND: Part of the esophagus is contiguous to the posterior wall (PW) of the left atrium (LA). Esophageal injury has occurred during LA ablation for atrial fibrillation (AF). The ability to identify the esophagus and monitor LAPW lesions with intracardiac echocardiography (ICE) has not been documented. METHODS: We report an index case of atrioesphageal fistula as a complication of transcatheter ablation of AF. After the index case, we retrospectively reviewed morphologic changes with radiofrequency (RF) delivered at LAPW during pulmonary vein (PV) electrical isolation using an 8-mm tip electrode (up to 70 W at a maximum of 50-52 degrees C for 60 seconds) or Chilli catheter (up to 50 W at a maximum of 40 degrees C for 60 seconds). ICE did not influence lesion application. After the index case, RF power was reduced at areas adjacent to the esophagus (8 mm/30-50 W at 50 degrees C or Chilli/40 W at a maximum of 38 degrees C). Duration of RF, 10-30 seconds, was titrated based on accelerated bubble formation or early echogenic lesion formation. RESULTS: The longitudinal extent of the contiguous LAPW-esophageal wall (length 18-59 mm) was identified in all 152 patients (ages 56 +/- 10 years, 117 men). Preablation LAPW (2.8 +/- 0.7 mm) and contiguous anterior esophageal wall (3.0 +/- 0.8 mm) thickness were noted. A total of 6 +/- 4.9 lesions/patient were delivered to the LAPW contiguous to the esophagus. Echogenic LAPW thickness increased to 7.5 +/- 2.1 mm (vs. 2.8 +/- 0.5 mm preablation) before the index case (n = 70 patients) and 4.7 +/- 1.6 mm (vs. 2.9 +/- 0.6 mm) after the index case (n = 67), with power reduction and titration of duration of energy delivery RF (P <.01) and PV isolation in all. CONCLUSIONS: The LAPW-esophageal region can be identified and monitored with ICE imaging during ablation procedures. RF lesions to the LAPW in PV isolation can produce dramatic morphologic changes immediately adjacent to the anterior esophageal wall. A reduction in power amount and duration as described coupled with online lesion monitoring to further titrate duration (<30 seconds) of power delivery decreases the depth of lesion formation and limits the risk of esophageal involvement.     

Accuracy of left atrial anatomical maps acquired with a multielectrode catheter during catheter ablation for atrial fibrillation

Introduction  

Left atrial geometry provided by preprocedural MRI/CT imaging studies is often used to guide pulmonary vein isolation. Rapid 3D reconstruction of the left atrium (LA) can be obtained using multielectrode catheters in conjunction with electro-anatomical mapping (EAM) and can also be used to guide ablation. The objective of this study is to assess the accuracy of electro-anatomical left atrial maps acquired with the multispine catheter by comparing them to CT and MRI images.     

The role of left atrial muscular bundles in catheter ablation of atrial fibrillation.

OBJECTIVES: We sought to investigate the imaging of the left atrial (LA) muscular bundle and the relationship between the bundle and inducibility of tachyarrhythmia after pulmonary vein isolation (PVI). BACKGROUND: Noninducibility is used as a clinical end point of atrial substrate ablation after PVI. However, little is known about the role of the LA muscular bundles in tachyarrhythmia after PVI. METHODS: Forty-three consecutive patients with paroxysmal atrial fibrillation who underwent catheter ablation were included. Bi-atrial isochronal mapping was performed with the NavX system (St. Jude Medical Inc., St. Paul, Minnesota) during sinus rhythm. After 4 PVI, inducible organized LA flutter with or without transforming to atrial fibrillation (AF) (LA flutter/AF) was ablated with additional lines at the roof and/or mitral isthmus. RESULTS: The existence of bilateral muscular bundles was an independent predictor of LA flutter/AF after PVI (p = 0.02). Patients with LA flutter/AF after PVI had a greater index of the double potentials (5.4 +/- 3.4% vs. 2.8 +/- 1.8%, p = 0.006) and interpotential interval (33 +/- 5 ms vs. 29 +/- 4 ms, p = 0.02) than without LA flutter/AF. The muscular bundles were identified in 28% patients using 16-slice multidetector computed tomography, which were identical to the isochrone map. Patients with noninducible LA flutter/AF after PVI plus the additional linear ablation had a lower recurrence rate as compared with the patients without it (19% vs. 75%, p = 0.02). CONCLUSIONS: Left atrial muscular bundles may provide a conduction block line and barrier, which is important for the formation of LA flutter/AF after PVI. The noninducibility of LA flutter/AF achieved after additional linear ablation may contribute to a better outcome in RF ablation of paroxysmal atrial fibrillation.     

Mechanical esophageal displacement during catheter ablation for atrial fibrillation

Esophageal Deviation in AF Ablation. Objective: To determine the feasibility and safety of esophageal displacement during atrial fibrillation (AF) ablation, to prevent thermal injury. Background: Patients undergoing AF ablation are at risk of esophageal thermal injury, which ranges from superficial ulceration, to gastroparesis, to the rare but catastrophic atrioesophageal fistula. A common approach to avoid damage is luminal esophageal temperature (LET) monitoring; however, (1) temperature rises mandate interruptions in energy delivery that interrupt workflow and potentially decrease procedural efficacy, and (2) esophageal fistulas have been reported even with LET monitoring. Methods: A cohort of 20 consecutive patients undergoing radiofrequency (RF) (16 patients) or laser balloon (4 patients) ablation of AF under general anesthesia. After barium instillation, the esophagus was deviated using an endotracheal stylet placed within a thoracic chest tube. LET monitoring was used during catheter ablation. Upper GI endoscopy was performed prior to discharge. Results: At the pulmonary vein level, leftward deviation measured 2.8 ± 1.6 cm (range: 0.4–5.7) and rightward deviation 2.8 ± 1.8 cm (range: 0.5–4.9). The temperature rose to >38.5 °C in 3/20 (15%) patients. In these 3 patients, there was an average of 2 applications/patient that recorded temperatures >38.5 °C. No patient had a temperature rise > 40 °C. Endoscopy revealed no esophageal ulceration from thermal injury in 18/19 (95%) patients; the sole patient with a thermally mediated ulceration had an unusual esophageal diverticulum fully across the posterior left atrium. Twelve patients (63%) exhibited trauma related to instrumentation with no clinical sequelae. Conclusions: Mechanical esophageal deviation is feasible and allows for uninterrupted energy delivery along the posterior wall during catheter ablation of AF. J Cardiovasc Electrophysiol, Vol. 23, pp. 147‐154, February 2012)