Morphology of the posterior junctional area in atrioventricular septal defects

Simplified primum ASD closure technique in complete VSD repair: shallow suture crossing on the AV node

The primum atrial septal defect suture line adjacent to the crux is performed carefully with various techniques to avoid atrioventricular block in repair of complete atrioventricular septal defect. We describe our technical modification to simplify the shallow suture line only into the endocardium above the atrioventricular node without conduction disturbance.

Development of the cardiac conduction system in atrioventricular septal defect in human trisomy 21

In patients with atrioventricular septal defect (AVSD), the occurrence of nonsurgical AV block has been reported. We have looked for an explanation in the development of the AV conduction system. Human embryos with AVSD and trisomy 21 and normal embryos were examined (age 5-16 wk gestation). Antibodies to human natural killer cell-1 (HNK-1), muscle actin (HHF-35), and collagen VI were used to delineate the conduction system. As in normal hearts, HNK-1 transiently stains the AV conduction system, the sinoatrial node, and parts of the sinus venosus in AVSD. A large distance is present between the superior and inferior node-like part of the right AV ring bundle, comparable to 6-wk-old normal hearts. The definitive inferior AV node remains in dorsal position from 7 wk onward and does not appose to the superior node-like part as seen in normal hearts. Furthermore, in AVSD, a transient third HNK-1-positive "middle bundle" branch that is continuous with the retroaortic root branch and the superior node-like part can be identified, and thus the AV conduction system forms a figure-of-eight loop. At later stages, the AV node remains in dorsal position close to the coronary sinus ostium with a long nonbranching bundle that runs through thin fibrous tissue toward the ventricular septum. The formation of the AV node and the ventricular conduction system in AVSD and Down syndrome differs from normal development, which can be a causative factor in the development of AV conduction disturbances.

Surgery for arrhythmias in children

BACKGROUND

Transcatheter radiofrequency ablation to treat supraventricular and ventricular arrhythmias has supplanted routine surgical ablative therapy and redefined its role. A small population of arrhythmia patients now requires surgical ablation: those who have failed catheter ablation, patients with concomitant congenital heart disease in association with arrhythmias, those with atrial fibrillation and very young patients for whom transcatheter techniques are prohibitive because of small size, cyanosis or distorted anatomy.

METHODS

From July 1992 through August 2003, 133 patients underwent arrhythmia surgery at Children's Memorial Hospital, 50% (67/133) in association with Fontan conversion (FC), 22% (28/133) with concomitant initial Fontan (IF) procedure and 28% (38/133) for various arrhythmias (MISC) in patients with (36/38, 95%) or without (2/38, 5%) associated structural heart disease. Mean age at surgery in the FC group was 20+/-7.6 years (median 19 years), and in the IF group and the MISC group, mean ages were 8.1+/-8.9 (median 4.2) years and 16.4+/-10.9 (median 11.3) years, respectively.

RESULTS

There were three operative (3/133, 2.6%; 1 FC, 2 MISC) and three late deaths (2 FC, 1 MISC). Four patients in the FC group had progressive ventricular failure and underwent successful cardiac transplantation. Follow-up data are available for non-transplant, surviving patients and reveal 11 incidences of persistent arrhythmia recurrence and 2 new-onset arrhythmias. Five of the 11 recurrences occurred early in our series of FC patients, when isthmus block interruption of arrhythmia foci was performed. Four additional recurrences occurred later in the FC series, two post-maze and two post-Cox-maze III. In the MISC group, there were two recurrences. Atrial reentry tachycardia (ART) recurred in a patient with no structural heart disease and accessory connection-mediated tachycardia recurred in a child who underwent concomitant initial Fontan. Two patients had ventricular tachycardia inducible at postoperative studies (2/7, 29%), but no clinical recurrence. Two new-onset tachycardias occurred, one child developed ART post-surgical ablation of accessory connections and one patient with inducible ventricular tachycardia developed ART 5 years postoperatively.

CONCLUSION

Variations in atrial and ventricular anatomy that may limit the catheter approach can be addressed surgically. Patient size or anatomic complexity should not be limiting factors in the combined surgical arrhythmia approach. Incorporation of arrhythmia therapy into planned surgical revision should be considered.

The beneficial effects of total cavopulmonary conversion and arrhythmia surgery for the failed Fontan

Postoperative Fontan patients can develop hemodynamic abnormalities and refractory atrial arrhythmias resulting in significant morbidity and mortality. We present our experience with total cavopulmonary artery conversion and arrhythmia surgery. Between 1994 and 2001, 41 patients underwent total cavopulmonary artery conversion and arrhythmia surgery. Significant hemodynamic lesions were repaired concomitantly: aortic aneurysm (n=1), atrioventricular valve insufficiency (n=8), and pulmonary artery stenosis (n=9). Thirty-five patients were in New York Heart Association class III or IV. Mean age at original Fontan was 7.5+/-6.5 years, at Fontan conversion, 18.7+/-9.0 years. Arrhythmia surgery for atrial re-entry tachycardia evolved from isthmus cryoablation (n=10) to right-sided maze (n=17). Maze-Cox III was used for 14 patients with atrial fibrillation. Atrial (n=34) and dual chamber (n=5) pacemakers were placed. Mortality and reoperation for bleeding rates are 0%. Chest tubes were removed on postoperative day 9.0+/-6.0. Mean hospital stay was 11.8+/-6.6 days. Three patients required cardiac transplantation at 8 days, 9 months, and 33 months postoperatively. There was one long-term death from acute myocardial infarction 2 years postoperatively. For the entire series, arrhythmia recurrence is 12.2% (5/41). Only 9.8% of patients (4/41) receive chronic antiarrhythmic medications; these patients were among the first eight in the series. Most patients are in New York Heart Association I or II. Bruce protocol in 12 patients showed increased tolerance (P<.05) Total cavopulmonary artery conversion with concomitant arrhythmia surgery is excellent therapy for patients with failed Fontan. It is safe, improves New York Heart Association class, improves exercise tolerance, and the incidence of recurrent arrhythmias is low.

Total cavopulmonary conversion and maze procedure for patients with failure of the Fontan operation

OBJECTIVES

Hemodynamic abnormalities and refractory atrial arrhythmias in patients late after the Fontan operation result in significant morbidity and mortality. We review our experience with conversion to total cavopulmonary artery connections and arrhythmia surgery.

METHODS

Between 1994 and 2001, 40 patients underwent Fontan conversion and arrhythmia surgery. Significant hemodynamic lesions such as aortic aneurysm (n = 1), atrioventricular valve insufficiency (n = 8), and pulmonary arterioplasty (n = 9) were repaired concomitantly. Thirty-four patients were in New York Heart Association class III or IV. Mean age at the original Fontan operation was 7.5 +/- 6.5 years and mean age at Fontan conversion was 18.7 +/- 9.0 years. Arrhythmia surgery has evolved from isthmus cryoablation in 10 patients to right-sided maze in 16 patients for atrial reentry tachycardia. The maze-Cox III operation was used for 14 patients with atrial fibrillation. Atrial (n = 33) and dual-chamber (n = 5) pacemakers were placed.

RESULTS

There has been no early mortality. Chest tubes were removed on postoperative day 9.0 +/- 6.0. Hospital stay was 11.8 +/- 6.6 days. Three patients required cardiac transplantation at 8 days, 9 months, and 33 months postoperatively. There was 1 death 2 years postoperatively from acute myocardial infarction. For the entire series, arrhythmia recurrence is 12.5%, with only 10% of patients receiving long-term antiarrhythmic medications; these patients were among the first 8 patients in our series. Most patients are in New York Heart Association class I or II. Bruce protocol in 12 patients showed increased tolerance (P <.05).

CONCLUSIONS

Fontan conversion to total cavopulmonary connection with concomitant arrhythmia surgery is excellent therapy for patients whose Fontan repair has failed. Fontan conversion is safe, improves New York Heart Association class, improves exercise tolerance, and has a low incidence of recurrent arrhythmias.

The surgical anatomy of ventricular septal defect part IV: double outlet ventricle

In this fourth part of our series of articles concerned with the surgical anatomy of ventricular septal defects (VSDs), we have analyzed the arrangements when both arterial trunks arise from the same ventricle. The essence of these anomalies is that the interventricular communication is an integral part of the circulation. Unless the surgeon constructs an alternative route of exit, closure of this defect would isolate one of the ventricles. The usual surgical approach, therefore, is to patch the hole between the ventricles into one or other of the subarterial outflow tracts. This means that all the components of the ventricular outflow tracts are of potential surgical importance. In hearts with double outlet right ventricle, the VSD can be categorized as being subaortic, subpulmonary, doubly committed, or non-committed. It is also important to determine whether its anatomical borders, as seen from the right ventricle, are in part fibrous or exclusively muscular, so as to establish the location of the atrioventricular conduction axis. It is possible, according to the nature of these borders, to place the defects into one of three groups, perimenbranous, muscular, or doubly committed and juxta-arterial. The size of the defect is another important surgical consideration. Double outlet left ventricle is a significantly more rare malformation, but the rules for determining the disposition of the conducting tissues are the same.