Intrapericardial balloon placement for prevention of collateral injury during catheter ablation of the left atrium in a porcine model

Intrapericardial balloon position. Anterior-posterior (AP) and left anterior oblique (LAO) views of the intrapericardial balloon positioned using different approaches: A: Direct puncture to the posterior pericardial space; B: anterior access with deflectable sheath guidance; C: postprocedural, in vivo photographs of inflated intrapericardial balloon (yellow arrow). PN along the pericardium is indicated by dashed white arrow. ESO = esophageal mapping catheter; PV Map = pulmonary vein mapping catheter.

Separation of the LA and esophagus during IPBP. A: Modified left lateral view of EA images; B: left anterior oblique (LAO) fluoroscopic view of the LA and contrast-filled esophagus, before and after balloon inflation in the same animal. In this case, balloon inflation caused simultaneous movement of the CIPV and esophagus away from each other. Esophagus and PV map catheter separation increased with balloon inflation. C: Right anterior oblique (RAO) view; D: posterior view of EA maps in the same porcine heart and esophagus shown in Figure 1A. During balloon inflation within the oblique sinus, the esophagus was markedly flattened (D) and shifted away from the posterior LA. The minimum distance between the LA and esophagus increased by 21 mm. ESO = esophagus; RSPV = right superior PV; LSPV = left superior PV; CIPV= common inferior PV; LAA = LA appendage; EPI = epicardial shell. PV map = pulmonary vein mapping catheter located at the CIPV ostium.

Luminal esophageal temperature. A: Fluoroscopic images of the positions of each electrode without IPBP (control, upper panel) and with balloon inflation (IPBP, middle panel) in the LAO fluoroscopic views. LAO EA images (lower panel). ESO = esophageal catheter; ABL = endocardial ablation catheter. B: Time courses of luminal esophageal temperature, mean arterial pressure (MAP), and heart rate (HR) during RF catheter ablation (RFCA) at the distal CIPV and during recovery. Temperature increased during control conditions (no IPBP, white circles) but was unchanged with balloon inflation. Overall temperature increased significantly in control conditions compared with in IPBP groups for all balloon sizes (P<.0001, ANOVA). At each time point during RFCA application and over 30 seconds of recovery, control temperatures were significantly greater than IPBP groups (P<.004, Student's t-test). There were no significant differences in the esophageal temperature between the smaller (12 mm, blue circles) and larger balloons (14–16 mm, red circles; P = .64, ANOVA). During RFCA application and recovery phases, MAP and HR did not change significantly.

PN protection. A, B: left and right anterior oblique, respectively, fluoroscopic images of the same porcine heart shown in Figure 1B. A 16 mm by 4 cm balloon was inflated near the anterior aspect of the RSPV via the transverse sinus (superior approach). A mapping catheter (Map) was positioned at the endocardial RSPV ostium for high-output pacing. Fluoroscopic AP (C) and right lateral EA (D) images of a second porcine heart show a 12 mm by 4 cm balloon inflated near the anterior aspect of the RSPV via an inferior approach. Red circles indicate sites with PN capture before balloon inflation.