Behavior of Unrepaired Perimembranous Ventricular Septal Defect in Young Adults Veerle Soufflet, MD, Alexander Van de Bruaene, MD, Els Troost, MD, Marc Gewillig, MD, PhD, Philip Moons, Nsc, PhD, Martijn C. Post, MD, PhD, and Werner Budts, MD, PhD* The number of adolescents and young adults with congenital heart defects, including ventricular septal defect (VSD), increases continuously. We evaluated the mid-term out- come of small and unclosed perimembranous VSDs (pmVSDs). All patients with a known unrepaired pmVSD at 16 years of age were selected from our database. The clinical, electrocardiographic, and echocardiographic changes between baseline and the latest fol- low-up examination were compared. A total of 220 patients (119 males, median age 18 years, interquartile range 7) could be included. During a median follow-up of 6 years (interquartile range 4, range 38), 2 patients died (1%; 1 from sudden death and 1 from end-stage heart failure). Endocarditis occurred in 8 patients (4%). One patient required pacemaker implantation (0.5%) and one required implantable cardioverter-defibrillator implantation (1%). Fifteen patients (7%) required a closing procedure. In 8 patients (4%), the pmVSD closed spontaneously. In the remaining 203 patients (93%), the QRS morphol- ogy changed in 5% and 1% lost sinus rhythm (p  0.0001 and p  0.015, respectively). The left ventricular ejection fraction and stroke volume index increased from 62  7% to 67  8% and from 41  11 to 44  15 ml/m 2 (p  0.0001 and p  0.035, respectively), the end-systolic diameter decreased, and the end-diastolic diameter did not change. Finally, patients with an open pmVSD developed more pulmonary arterial hypertension during follow-up (from 3% to 9%, p  0.002). In conclusion, mid-term follow-up of adolescents and young adults with a small and unrepaired pmVSD was not uneventful. Some patients required intervention, but in others, spontaneous closure occurred. Electrocardiographic and structural changes were noticed, for which the clinical significance needs to be determined. © 2010 Elsevier Inc. All rights reserved. (Am J Cardiol 2010;105:404 – 407) Perimembranous ventricular septal defects (pmVSDs), which include about 70% to 80% of all VSDs, involve the membranous septum and the adjacent area of the muscular septum. Spontaneous and functional closure might occur when the septal leaflet of the tricuspid valve covers the defect. Muscular VSDs are present in 15% of the cases, and 1/2 of them close spontaneously by muscular in-growth. The rare, doubly committed, VSDs, which account for 5% of all VSDs, might also close spontaneously when the right coronary cusp prolapses into the defect. Small VSDs with- out any hemodynamic repercussion are usually treated con- servatively and remain unrepaired. The long-term results of this policy are undetermined. It is unknown whether these patients have a normal life expectancy. However, such in- formation might be critically important with regard to future patients’ employability and insurability. The objective of the present study was to determine the evolution and mid- term outcome of young adults with a perimembranous VSD (pmVSD) that was still open at 16 years of age. Methods All patients, registered with an unrepaired pmVSD at 16 years of age, were selected from our database of pediatric and congenital cardiology. It contains 20,000 patients with con- genital heart defects. Of these patients, 7,000 are 16 years old. Our department of pediatric and congenital cardiology yearly performs 300 interventional catheterizations, and 200 patients are referred to the congenital cardiac surgeon. Only restrictive VSDs were allowed to be included. All pa- tients in whom the pmVSD was unrepaired at 16 years of age were suggested to have a pulmonary output/systemic output (Qp/Qs) ratio of 1.5:1. Patients in whom the VSD closed spontaneously or was closed surgically before 16 years of age and patients who had associated complex congenital anomalies were not included in the present study. The institutional ethics committee of the hospital approved the study protocol. The patient files were primarily reviewed for demo- graphic data and events after the age of 16 years. The events were defined as death, spontaneous VSD closure, surgical VSD closure, percutaneous VSD closure, the occurrence of endocarditis, implantation of a pacemaker or implantable cardioverter-defibrillator. Secondarily, the electrocardiographic and transthoracic echocardiographic data were collected. We looked for heart rate, atrioventricular conduction time, QRS duration, type of QRS morphology, and type of rhythm (sinus rhythm or not). The left ventricular ejection fraction (obtained by M-mode and Cardiology and Pediatric Cardiology, University Hospitals Leuven, Belgium, Leuven. Manuscript received August 11, 2009; revised manu- script received and accepted September 9, 2009. *Corresponding author: Tel: (00) 32-16-34-4369; fax: (00) 32-16-34- 4369. E-mail address: Werner.Budts@uz.kuleuven.ac.be (W. Budts). 0002-9149/10/$ – see front matter © 2010 Elsevier Inc. All rights reserved. www.AJConline.org doi:10.1016/j.amjcard.2009.09.047