Commentary: Advanced imaging technologies may help to eliminate the need for pacemaker implantation following repair of ventricular septal defect

Abstract

Central MessageNew imaging and 3D reconstructive technologies may help to avoid pacemaker implantation following repair of complex congenital malformations associated with ventricular septal defect.See Article page 490. New imaging and 3D reconstructive technologies may help to avoid pacemaker implantation following repair of complex congenital malformations associated with ventricular septal defect. See Article page 490. Iatrogenic heart block remains a risk factor for surgical closure of ventricular septal defects (VSDs), with a reported incidence between 2% and 8%. In a single-center, retrospective study with more than 800 patients (mean age, 14 months) undergoing operation between 2001 and 2009, a total of 64 patients (7.7%) developed iatrogenic atrioventricular block. Forty-eight of them (75%) had transient atrioventricular block, whereas 16 (1.9%) required pacemaker implantation.1Siehr S.L. Hanley F.L. Reddy V.M. Miyake C.Y. Dubin A.M. Incidence and risk factors of complete atrioventricular block after operative ventricular septal defect repair.Congenit Heart Dis. 2014; 9: 211-215Crossref PubMed Scopus (23) Google Scholar Patients weighing <4 kg and those with inlet VSD were more likely to develop atrioventricular block following surgical VSD repair. In another recent study by Sen and colleagues2Sen O. Kadirogullari E. Aydin U. Guler S. Haydin S. Comparison of continuous and interrupted suturing techniques in ventricular septal defect closure.Heart Surg Forum. 2018; 21: E418-E422Crossref PubMed Scopus (1) Google Scholar that included 286 patients, the type of suturing technique (interrupted vs continuous) had no significant influence on perioperative mortality and morbidity such as complete atrioventricular block (6.8% vs 5.2%). Yoshitake and colleagues3Yoshitake S. Kaneko Y. Morita K. Hoshino S. Oshima Y. Masashi T. et al.Visualization and quantification of the atrioventricular conduction axis in hearts with ventricular septal defect using phase contrast computed tomography using phase-contrast computed tomography.J Thorac Cardiovasc Surg. 2020; 160: 490-496Abstract Full Text Full Text PDF Scopus (6) Google Scholar performed a nice (postmortem) analysis of 8 hearts from pediatric patients with a perimembranous VSD. They used a combination of imaging (radiograph phase-contrast computed tomography) with 3-dimensional reconstruction software to provide the best possible analysis of the course and location of the atrioventricular conduction system. Similar anatomical analyses were performed decades ago and therefore the present study mainly confirms the available knowledge. Among the main advantages of this technology is that Amira software (ThermoFisher Scientfic, Waltham, Mass) reconstruction made it possible to get a view similar to that of a surgeon in an operating room through reorientation of the dataset and to provide different views of the most vulnerable parts of the suture line. Although the occurence of complete atrioventricular block following VSD repair is low, major interest may be focused on more complex intracardiac pathologies associated with VSD like tetralogy of Fallot, transposition, or double-outlet right ventricle. This is also true for patients with congenitally corrected transposition where uncertainty remains regarding the location of the conduction axis when this combination is found in the setting of mirror-imaged atrial arrangement. The described method is appealing but it will need maximal attention by surgical teams to translate the exact location of the atrioventricular conduction bundle as well as the atrioventricular node into the surgical anatomy at the time of VSD closure, although longitudinal—not perpendicular—sutures are placed at the level of the inferoposterior rim of the defect. It would be extremely useful to have precise knowledge of the location of the bundle as part of the preoperative assessment to prevent the rare but significant complication of postoperative heart block. Among the most important limitations is the fact that the authors cannot confirm that this type of imaging analysis may be applied to living hearts. Computed imaging technologies will get better, as every technology does. Visualization and quantification of the atrioventricular conduction axis in hearts with ventricular septal defect using phase contrast computed tomographyThe Journal of Thoracic and Cardiovascular SurgeryVol. 160Issue 2PreviewTo visualize and quantify the atrioventricular conduction axis in the setting of ventricular septal defect using phase contrast computed tomography. Full-Text PDF Open Access