Gerbode-Type Defect Induced by Catheter Ablation of the Atrioventricular Node

Abstract

A 72-year-old man with a history of dilated cardiomyopathy, prosthetic aortic valve, biventricular intracardiac pacemaker, and permanent atrial fibrillation presented with uncontrolled ventricular response from atrial fibrillation despite pharmacological therapy. He underwent radiofrequency (RF) catheter ablation of the atrioventricular (AV) node to achieve optimal biventricular pacing.AV node ablation was performed via the right femoral vein with a 4-mm tip ablation catheter (EPT, BostonScientific) positioned at the AV node just proximal to the His bundle region. RF energy was applied at this site for 60 seconds (55°C) resulting in complete heart block with an escape rhythm of 32 bpm. The next day he was discharged uneventfully. An echocardiogram at 5 months follow-up showed a left ventricular to right atrial (LV-RA) shunt across the membranous septum immediately above the tricuspid valve (online-only Data Supplement Movies I and II and Figure 1A and 1B). This LV-RA shunt (Gerbode-type defect) had a 76-mm Hg gradient across the defect ( Figure 1C). Left ventricular ejection fraction was depressed (25% to 30%) and the right ventricle was mildly to moderately dilated. The mechanical aortic prosthetic valve functioned normally with a mean gradient of 17 mm Hg. Review of the patient's preablation echocardiographic studies did not show any evidence of LV-RA shunt. He remained stable with New York Heart Association class I to II and Ͼ85% biventricular pacing. A repeat echocardiographic study 14 months after the ablation procedure did not show any progression in the size of iatrogenic Gerbode-type defect or shunting.In a second case, a 68-year-old man with a history of severe chronic obstructive pulmonary disease and symptomatic permanent atrial fibrillation underwent RF catheter ablation of the AV node because of ineffective ventricular rate control by medical therapy. Three days after the procedure, the patient developed ventricular fibrillation and could not be resuscitated. Autopsy findings showed lesions at the RF ablation sites. Although he did not develop a frank defect, the ablation lesions extended to the left ventricular side of the membranous septum (Figure 2) at a site similar to the Gerbode-type defect in the first patient.

Expert review Left ventricular to right atrial shunt (Gerbode defect): congenital versus acquired

“…The retrieval resulted in a collection of 111 articles [ 2 – 113 ], which included 77 (59.3%) case reports [ 3 , 5 – 7 , 9 , 12 – 14 , 16 , 17 , 19 – 23 , 25 – 28 , 30 , 33 , 35 – 37 , 39 , 42 , 44 – 54 , 57 , 59 – 61 , 63 – 67 , 71 , 76 – 80 , 82 , 84 – 89 , 92 – 97 , 99 – 107 , 110 – 112 ] (including 8 (7.4%) case reports in the name of “letter to the editor” [ 5 , 25 , 26 , 30 , 79 , 84 , 92 , 111 ]), 17 (17.6%) medical images [ 2 , 10 , 11 , 15 , 22 , 32 , 40 , 41 , 43 , 58 , 69 , 70 , 72 , 74 , 98 , 108 , 109 ], 5 (4.6%) case series [ 8 , 18 , 34 , 38 ...…”

Fibrous Skeleton of the Heart: Anatomic Overview and Evaluation of Pathologic Conditions with CT and MR Imaging

“…A congenital or acquired isolated defect of the AV component of the membranous septum with a left-to-right shunt is known as a Gerbode defect (38). Perforation of the AV portion of the membranous septum during direct compact AV node ablation could induce a Gerbode-type shunt (40).…”

Clinical cardiac structural anatomy reconstructed within the cardiac contour using multidetector‐row computed tomography: The arrangement and location of the cardiac valves

“…The atrioventricular portion of the septum is the focal thin membrane located where the right atrium directly faces the left ventricle (Anderson et al, ; Mori et al, ). Several clinical situations have been reported to be associated with this important structure (Gerbode et al, ; Wasserman et al, ; Ergun et al, ; Can et al, ).…”