When the atrioventricular node is damaged, accessory pathways can perform primary atrioventricular conduction but may spontaneously degrade during childhood. After surgical atrial septal defect repair during infancy, an adolescent male presented with fatigue due to iatrogenic complete atrioventricular node block with a degrading antegrade accessory pathway resulting in symptomatic bradyarrhythmia.

Newborn male with symptomatic bradycardia initially diagnosed with complete atrioventricular block. Isoproterenol drip was initiated, and the patient was scheduled for pacemaker implantation. During the hospital course, repeat electrocardiogram and Holter monitor revealed evidence of near continuous blocked atrial bigeminy with occasional aberrantly conducted premature atrial contractions. Flecainide was started, resulting in normal sinus rhythm, and the pacemaker implantation was cancelled.

This case illustrates acute myocarditis with complete heart block in a 13-year-old teenager as a rare complication of acute dengue illness. He required urgent temporary pacing with inotropic support and antifailure medications. Complete heart block in dengue myocarditis is an acute but reversible condition. A similar presentation in a dengue-endemic country or with a history of travelling to tropical countries warrants a suspicion of dengue infection.

Fetal hydrops is a serious complication of immune-mediated congenital complete atrioventricular block. We present the case of a fetus with severe hydrops and profound bradycardia and an unusual favourable outcome. This case enhances the importance of considering the contribution of ventricular ectopic beats to the cardiac output when counselling and predicting outcome of complete heart block.

At present, there are many pacing strategies for young patients with complete atrioventricular block. The most frequent policy is to attempt placing a dual-chamber system when possible; however, there is a group of patients that is functioning with a non-synchronous ventricular pacing, raising the question of the ideal timing to upgrade their systems. We investigated the exercise performance of a group of children and young adults with complete atrioventricular block and dual-chamber pacemakers in both single- and dual-chamber pacing modalities. A total of 15 patients performed maximal exercise stress testing after programming the VVIR or DDD modes with 2 hours of interval in a double-blind study protocol.

Compared with VVIR pacing, DDD pacing resulted in increase in the peak VO2, longer test duration, major increase in the heart rate achieved during peak exercise, decreased systemic non-invasive arterial blood pressure measured at maximal exercise, higher maximal workload, prolongation of the anaerobic threshold timing, and better self-rated performance perception in all the patients.

Synchronous atrioventricular pacing contributes to an increase in both the exercise performance and the performance perception in 100% of the patients. This difference contributes to create a sense of “fitness” with repercussions in the overall health, self-esteem, and life quality, as well as encourages youngster to practice sports. Our experience tends to favour upgrading patients’ systems to dual-chamber systems before reaching the adolescent years, even if the centre policy is to prolong as long as possible the epicardial site in order to avoid long years of right ventricular pacing.

In hypoplastic left heart syndrome, thrombosis of the native ascending aorta is rare and often fatal; there are no previously reported cases presenting with acute heart block. We review a case of native ascending aorta thrombosis in a 2-year-old boy with hypoplastic left heart syndrome, presenting with acute heart block. This case highlights the benefit of multi-modality imaging in complex cases.

Surgical Management of straddling tricuspid valve and associated defects is a complex problem. Between August 1992 and August 1995, 5 patients with major straddling of the tricuspid valve underwent a complete or partial biventricular repair. All patients had either an inlet ventricular septal defect (n=4) or a ventricular septal defect with an inlet component (n=1), Co-existing cardiac lesions included hypoplasia of the right ventricle (n=3), discordant ventriculoarterial connections (n=1), tetralogy of Fallot (n=1), and multiple muscular vetricular septal defects (n=2). At the time of presentation to our institution, two of these patients had previously been palliated in preparation for a Fontan procedure, having undergone construction of a bidirectional superior cavopulmonary shunt. One patient was referred specifically for a Fontan procedure. The tricuspid valve was repaired by transecting all of the straddling cords and reattaching them in the right ventricle or onto the right side of the patch used to close the ventricular septal defect. Associated procedures included closure of the septum in all patients, an arterial switch procedure in one, repair of tetralogy of Fallot in one, and construction of a bidirectional superior cavopulmonary shunt in one. There has been no early or late mortality. Complete heart block requiring insertion of a pacemaker occurred after surgery in three patients. At a median follow-up of 32 months, functional integrity of the tricuspid valve is well maintained, with only one patient having moderate tricuspid regurgitation. None of the patients are receiving any cardiac medication.

A left-sided hepatic vein connected to the coronary sinus is reported in a case of a 22-month-old boy with isomerism of the left atrial appendages, complete atrioventricular septal defect and azygous continuation of the inferior caval vein. The diagnosis of the anomalous hepatic vein was made intraoperatively and successful biventricular repair has been accomplished. To the best of our knowledge, this is the first communication on this peculiar entity diagnosed during life, notwithstanding Nabarro's description of a similar autopsy finding in 1903. Aspects of the development of this rare entity are discussed.

We report a 12-year-old boy with hypertrophic cardiomyopathy presenting with syncope. His electrocardiogram showed first-degree atrioventricular block, complete right bundle branch block, conduction delay in the anterior fascicle of the left bundle branch, and intermittent complete atrioventricular block. We detected hypertrophic cardiomyopathy in the mother. The relationship between the diseases is discussed, and interpreted in the light of previous descriptions.

Extracorporeal shock wave lithotripsy using a spark gap generator is contraindicated in patients with complete atrioventricular heart block. A case of a patient with such a heart block, who successfully underwent renal lithotripsy, without cardiac pacemaker, is reported.