Search

Atrial septal defect (ASD) closure by interventional catheterization techniques has been widely accepted and is considered a standard treatment for this congenital heart defect. We report the case of a 6-year-old girl who presented with progression of first-degree atrio-ventricular (AV) block to symptomatic, complete heart block after ASD closure with an Amplatzer septal occluder (ASO). Although she received steroids immediately after the procedure when second-degree AV block was seen, her AV conduction slowly deteriorated over 4 years, requiring permanent pacemaker implantation. We can only speculate that the injury to the conduction system was the result of persistent trauma, ischemia, or progressive scarring caused by the ASO on the AV nodal region. It is uncertain if early device removal would have prevented this complication. This case highlights the importance of cardiac rhythm monitoring following ASO implantation for ASD closure on long-term follow-up.

Background: The incidence of atrial tachycardia following Fontan surgery is high, but access to the pulmonary venous atrium, a frequent site of arrhythmia origin, is limited., Objectives: The purpose of this study is to report our results with a novel transthoracic percutaneous technique that provides direct access to the pulmonary venous atrium for electrophysiologic procedures., Methods: Six transthoracic ablation procedures were performed in five patients (age 1.2-17 years, weight 9.2-68.4 kg) with a lateral tunnel Fontan. Under biplane fluoroscopy, a percutaneous needle was advanced at the selected intercostal space toward the pulmonary venous atrium. Once access was confirmed, a sheath was placed over a wire and a Navistar CARTO catheter advanced for mapping and ablation. Additional catheters were placed in the baffle and esophagus for pacing and reference. Atrial tachycardia was induced, electroanatomic mapping performed, and candidate areas tested with entrainment techniques. Radiofrequency ablation was performed and success defined as the inability to reinduce tachycardia using the initiating protocol., Results: All tachycardias were ablated. Procedure time ranged from 3.7 to 4.9 hours, and fluoroscopy time ranged from 31 to 70 minutes. Hospital stay was 2 days. One patient had a pneumothorax and two had a hemothorax that was drained. Tachycardia recurred in one patient at 3 months. Ablation was repeated successfully. Four patients are free of tachycardia at follow-up ranging from 6 to 29 months. Follow-up is not available for one child., Conclusion: Transthoracic percutaneous access provided a direct route to the pulmonary venous atrium for successful mapping and radiofrequency ablation in Fontan patients.

Fetal cardiac arrhythmias have been recognized with increasing frequency during the past several years. Most fetal arrythmias are intermittent extrasystoles, often presenting as irregular pauses of rhythm. These are significant only when they occur with appropriate timing to initiate sustained tachycardia, mediated by anatomic bypass pathways. The most common important fetal arrhythmias are: 1) supraventricular tachycardias, and 2) severe bradyarrhythmias, associated with complete heart block. Symptomatic fetal tachycardias are usually supraventricular in origin, and may be associated with the developmet of hydrops fetalis. These patients may respond to antiarrhythmic drug therapy, administered via maternal ingestion or via direct fetal injection. Such therapy should be offered with careful fetal and maternal monitoring, and must be based on a logical, sequential analysis of the electrical mechanism underlying the arrhythmia, and an appreciation of the pharmacology and pharmacokinetics of the maternal, placental fetal system. Bradycardia from complete heart block may either be associated with complex congential heart malformations involving the atrioventricular junction of the heart, or may present in fetuses with normal cardiac structure, in mothers with autoimmune conditions associated with high titres of anti-SS-A or anti-SS-B antibody, which cross the placenta to cause immune-related inflammatory damage to the fetal atroventricular node. This paper reviews experience with the analysis of fetal caridac rhythm, a detailed discussion of the pathophysiology of arrhythmias and their effect on the fetal circulatory system, and offers a logical framework for the construction of treatment algorithms for fetuses at risk for circulatory compromise from fetal arrhythmias.

Objectives: To assess the incidence and establish possible predictors of late recovery of post-surgical heart block, treated with pacemaker implantation, in patients with congenital heart defects., Background: The American College of Cardiology/American Heart Association Task Force has recommended pacemaker implantation for advanced second or third degree atrioventricular block which persists for 7 to 14 days after surgery. The incidence of late recovery of post-surgical heart block following pacemaker implantation has not been reported., Methods: Records of 44 patients with post-surgical heart block who underwent pacemaker implantation at our institutions since 1976 were reviewed for demographic, anatomic, surgical and surface electrocardiographic data to assess the incidence of, and factors associated with, recovery of atrioventricular conduction on long-term follow-up., Results: 32% (14) of patients recovered atrioventricular conduction at a median follow-up of 5.5 years while 68% (30) remained pacemaker dependent. The groups were similar in age and weight at surgery and period of follow-up p = 0.5). Types of defect and surgical repair were not significantly different (p > 0.1). There was a similar number of patients with second degree-type II block in both groups (p = 0.15). The groups did not differ in timing of pacemaker implantation (<10 days p = 0.14, >14 days p = 0.18)., Conclusions: Late recovery of atrioventricular conduction following pacemaker implantation for postsurgical heart block is common. However, clinical predictors, with reference to current recommendations, could not be identified. Prospective electrophysiologic evaluations may be warranted to establish guidelines for long term pacemaker dependency and criteria for pacing.

An adolescent with hypophosphatemic rickets developed cardiac calcifications in the absence of hypercalcemia or elevation of the phosphocalcic product (the product of the total serum calcium and phosphorus concentrations). Cardiac calcifications led to aortic and mitral valve dysfunction, myocardial calcification, and arrhythmia. Hyperparathyroidism probably played a significant role in the development of this complication, which emphasizes the necessity for intermittent assessment of parathyroid status in individuals receiving medical therapy for hypophosphatemic rickets.

Objective: We report 16 infants with complete congenital heart block (CHB) who developed late-onset dilated cardiomyopathy despite early institution of cardiac pacing., Background: Isolated CHB has an excellent prognosis following pacemaker implantation. Most early deaths result from delayed initiation of pacing therapy or hemodynamic abnormalities associated with congenital heart defects., Methods: A multi-institutional study was performed to identify common clinical features and possible risk factors associated with late-onset dilated cardiomyopathy in patients born with congenital CHB., Results: Congenital heart block was diagnosed in utero in 12 patients and at birth in four patients. Ten of 16 patients had serologic findings consistent with neonatal lupus syndrome (NLS). A pericardial effusion was evident on fetal ultrasound in six patients. In utero determination of left ventricular (LV) function was normal in all. Following birth, one infant exhibited a rash consistent with NLS and two had elevated hepatic transaminases and transient thrombocytopenia. In the early postnatal period, LV function was normal in 15 patients (shortening fraction [SF] = 34 +/- 7%) and was decreased in one (SF = 20%). A cardiac pacemaker was implanted during the first two weeks of life in 15 patients and at seven months in one patient. Left ventricular function significantly decreased during follow-up (14 days to 9.3 years, SF = 9% +/- 5%). Twelve of 16 patients developed congestive heart failure before age 24 months. Myocardial biopsy revealed hypertrophy in 11 patients, interstitial fibrosis in 11 patients, and myocyte degeneration in two patients. Clinical status during follow-up was guarded: four patients died from congestive heart failure; seven required cardiac transplantation; one was awaiting cardiac transplantation; and four exhibited recovery of SF (31 +/- 2%)., Conclusions: Despite early institution of cardiac pacing, some infants with CHB develop LV cardiomyopathy. Patients with CHB require close follow-up not only of their cardiac rate and rhythm, but also ventricular function.

Successful stent implantation for conduit stenosis has been described; however, this procedure may be complicated by compression of adjacent structures during expansion. We report on a rare case of a single right coronary artery system complicating stent implantation for relief of homograft stenosis in tetralogy of Fallot.

Anomalous left coronary artery (ALCA) from the pulmonary trunk presents in early infancy with a clinical picture of failure to thrive, congestive heart failure (CHF), angina-like episodes, and mitral insufficiency. These manifestations which are due to myocardial ischemia may change in the presence of an associated lesion. We present a case and review two previous reports of a patent ductus arteriosus (PDA) associated with this anomaly. Although signs and symptoms are not as clear due to the less impaired coronary perfusion and the presence of a PDA, the presence of mitral insufficiency should raise the possibility of an anomalous coronary artery and, therefore, a cardiac catheterization and angiocardiography are recommended in anticipation of reparative surgery.