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Background: The relationship between congenital heart disease (CHD) and malignancies has not been determined. This study aimed to explore the association of CHD with malignancies and examine the risk factors for the development of cancer after a diagnosis of CHD., Patients and Methods: This nationwide, population-based cohort study on cancer risk evaluated 31,961 patients with newly diagnosed CHD using the Taiwan National Health Insurance Research Database (NHIRD) between 1998 and 2006. The standardized incidence ratios (SIRs) for all and specific cancer types were analyzed, while the Cox proportional hazard model was used to evaluate risk factors of cancer occurrence., Results: Among patients with newly diagnosed CHD regardless of ages, 187 (0.6%) subsequently developed cancers after a diagnosis of CHD. Patients with CHD had increased risk of cancer (SIR, 1.45; 95% CI, 1.25-1.67), as well as significantly elevated risks of hematologic (SIR, 4.04; 95% CI, 2.76-5.70), central nervous system (CNS) (SIR, 3.51; 95% CI, 1.92-5.89), and head and neck (SIR, 1.81; 95% CI, 1.03-2.94) malignancies. Age (HR, 1.06; 95% CI, 1.05-1.06) and co-morbid chronic liver disease (HR, 1.91; 95% CI, 1.27-2.87) were independent risk factors for cancer occurrence among CHD patients., Conclusion: Patients with CHD have significantly increased cancer risk, particularly hematologic, CNS, and head and neck malignancies. Physicians who care for patients with CHD should be aware of their predisposition to malignancy after the diagnosis of CHD. Further studies are warranted to clarify the association between CHD and malignancies.

The SCN5A mutations have been associated with a variety of arrhythmic disorders, including type 3 long QT syndrome (LQT3), Brugada syndrome and inherited cardiac conduction defects. The relationship between genotype and phenotype in SCN5A mutations is complex. Some SCN5A mutations may cause death or severe manifestations in some people and may not cause any symptoms or arrhythmias in others. The causes of these unpredictable clinical manifestations remain incompletely understood. The molecular basis of a four-generation family with cardiac conduction abnormalities was studied and whether variants in the SCN5A gene could account for the cardiac phenotypic variability observed in this family was determined. A novel mutation (W1421X) of SCN5A was identified in a four-generation family with cardiac conduction abnormalities and several cases of sudden death. Most family members who carry this W1421X mutation have developed major clinical manifestations or electrocardiographic abnormalities, both of which became more prominent as the patients grew older. However, the 73-year-old grandfather, who carried both the W1421X and R1193Q mutations, had thus far remained healthy and presented with only subtle electrocardiographic abnormalities, whereas most of his offspring, who carried a single mutation (W1421X), had died early or had major disease manifestations. This observation suggests that the R1193Q mutation has a complementary role in alleviating the deleterious effects conferred by W1421X in the function of the SCN5A gene. This report provides a good model to explain the mechanism of penetrance of genetic disorders.

Background: Nonpulmonary vein (PV) ectopy initiating atrial fibrillation (AF)/atrial tachycardia (AT) is not uncommon in patients with AF. The relationship of complex fractionated atrial electrograms (CFAEs) and non-PV ectopy initiating AF/AT has not been assessed. We aimed to characterize the CFAEs in the non-PV ectopy initiating AF/AT. Methods: Twenty-three patients (age 53 ± 11 y/o, 19 males) who underwent a stepwise AF ablation with coexisting PV and non-PV ectopy initiating AF or AT were included. CFAE mapping was applied before and after the PV isolation in both atria by using a real-time NavX electroanatomic mapping system. A CFAE was defined as a fractionation interval (FI) of less than 120 ms over 8-second duration. A continuous CFAE (mostly, an FI < 50 ms) was defined as electrogram fractionation or repetitive rapid activity lasting for more than 8 seconds. Results: All patients (100%) with non-PV ectopy initiating AF or AT demonstrated corresponding continuous CFAEs at the firing foci. There was no significant difference in the FI among the PV ostial or non-PV atrial ectopy or other atrial CFAEs (54.1 ± 5.6, 58.3 ± 11.3, 52.8 ± 5.8 ms, P = 0.12). Ablation targeting those continuous CFAEs terminated the AF and AT and eliminated the non-PV ectopy in all patients (100%). During a follow-up of 7 months, 22% of the patients had an AF recurrence with PV reconnections. There was no recurrence of any ablated non-PV ectopy during the follow-up. Conclusion: The sites of the origin of the non-PV ectopies were at the same location as those of the atrial continuous CFAEs. Those non-PV foci were able to initiate and sustain AF/AT. By limited ablation targeting all atrial continuous CFAEs, the AF could be effectively eliminated. [ABSTRACT FROM AUTHOR]

Abstract: Background: Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common supraventricular tachycardia in adulthood. Although selective ablation of the slow AV nodal pathway can cure AVNRT, accidental AV block may occur. The details on the electrophysiologic characteristics, quantitative data on the voltage inside Koch''s triangle, and the use of three-dimensional noncontact mapping to facilitate the catheter ablation of AVNRT associated with a high-risk for AV block or other arrhythmias have been limited. Methods and results: Nine patients (M/F =5/4, 34±23 years, range 17–76) with clinically documented AVNRT were included. All patients had undergone previous sessions for slow AV nodal pathway ablation but they had failed, because of repetitive episodes of complete AV block during the RF energy applications. Further, one patient had a complex anatomy and 4 patients were associated with other tachycardias, respectively. The electrophysiologic studies revealed that 4 patients had the slow–fast, 4 the slow–intermediate and one the fast–intermediate form of AVNRT. Noncontact mapping demonstrated two types of antegrade AV nodal conduction, markedly differing sites of the earliest atrial activation during retrograde VA conduction, and a lower range of voltage within Koch''s triangle. The lowest border of the retrograde conduction region was defined on the map, and the application of the RF energy was delivered below that border to prevent the occurrence of AV block. The distance between the successful ablation lesions and the lowest border of the retrograde conduction region was significantly shorter in the patients with the slow–intermediate form of AVNRT than in those with the slow–fast form (5.5±3.4 vs. 15±7.6 mm; p <0.05). After the ablation procedure, either rapid pacing or extrastimulation could not induce any tachycardia, and there was no recurrence during the follow-up (10.3±5.4, 2 to 22 months). Conclusions: Noncontact mapping could effectively demonstrate the antegrade and retrograde atrionodal conduction patterns, electrophysiologic characteristics of Koch''s triangle, and guide the successful catheter ablation in difficult AVNRT cases. [Copyright &y& Elsevier]

Backgrounds: Radiofrequency (RF) catheter ablation represents a major advance in the management of children with cardiac arrhythmias and has rapidly become the standard of care for the first-ling therapy of supraventricular tachycardias (SVTs). The purpose of this study was to investigate the results of the RF catheter ablation of SVTs in pediatric patients. Methods: From December 1989 to August 2005, a total of 228 pediatric patients (age: 9 ± 7 years, range: 5–18 years; male:female = 117:111) with clinically documented SVT underwent an electrophysiologic study and RF catheter ablation at our institution. Results: The arrhythmias included atrioventricular reentrant tachycardia (AVRT; n = 140, 61%), atrioventricular nodal reentrant tachycardia (AVNRT; n = 66, 29%), atrial tachycardia (AT; n = 11, 5%), and atrial flutter (AFL; n = 11, 5%). The success rate of the RF catheter ablation was 92% for AVRT, 97% for AVNRT, 82% for AT, and 91% for AFL, respectively. Procedure-related complications were infrequent (8.7%; major complications: high grade AV block (2/231, 0.9%); minor complications: first degree AV block (6/231, 2.6%), reversible brachial plexus injury (2/231, 0.9%), and local hematomas or bruises (10/231, 4.3%)). The recurrence rate was 4.7% (10/212) during a follow-up period of 86 ± 38 months (0.5–185 months). Conclusions: The RF catheter ablation was a safe and effective method to manage children with paroxysmal and incessant tachycardia. The substrates of the arrhythmias differed between the pediatric and adult patients. However, the success rate of the ablation, complications, and recurrence during childhood were similar to those of adults. [ABSTRACT FROM AUTHOR]

Background: The majority of cardiac arrhythmias in children are supraventricular tachycardia, which is mainly related to an accessory pathway (AP)-mediated reentry mechanism. The investigation for Wolff-Parkinson-White (WPW) syndrome in adults is numerous, but there is only limited information for children. This study was designed to evaluate the specific electrophysiologic characteristics and the outcome of radiofrequency (RF) catheter ablation in children with WPW syndrome. Methods: From December 1989 to August 2005, a total of 142 children and 1,219 adults with atrioventricular reentrant tachycardia (AVRT) who underwent ablation at our institution were included. We compared the clinical and electrophysiologic characteristics between children and adults with WPW syndrome. Results: The incidence of intermittent WPW syndrome was higher in children (7% vs 3%, P= 0.025). There was a higher occurrence of rapid atrial pacing needed to induce tachycardia in children (67% vs 53%, P= 0.02). However, atrial fibrillation (AF) occurred more commonly in adult patients (28% vs 16%, P = 0.003). The pediatric patients had a higher incidence of multiple pathways (5% vs 1%, P < 0.001). Both the onset and duration of symptoms were significantly shorter in the pediatric patients. The antegrade 1:1 AP conduction pacing cycle length (CL) and antegrade AP effective refractory period (ERP) in children were much shorter than those in adults with manifest WPW syndrome. Furthermore, the retrograde 1:1 AP conduction pacing CL and retrograde AP ERP in children were also shorter than those in adults. The antegrade 1:1 atrioventricular (AV) node conduction pacing CL, AV nodal ERP, and the CL of the tachycardia were all shorter in the pediatric patients. Conclusion: This study demonstrated the difference in the electrophysiologic characteristics of APs and the AV node between pediatric and adult patients. RF catheter ablation was a safe and effective method to manage children with WPW syndrome. [ABSTRACT FROM AUTHOR]

Noncontact Mapping of Typical Atrial Flutter. Introduction: The aim of this study was to delineate activation patterns around the crista terminalis (CT) using high-resolution noncontact mapping. Methods and Results: Twenty-six patients with typical atrial flutter (20 counterclockwise and 6 clockwise) were enrolled in the study. A noncontact mapping system was used to map atrial flutter. There were three activation patterns around the line(s) of block. Type I (n = 6) showed activation around a single complete line of block located in the CT. Type II (n = 17) showed activation around a single incomplete line of block with a conduction gap in the CT. Type III (n = 3) showed activation around double lines of block, one located in the CT and the other located in the sinus venosa region. Simultaneous activation around the tricuspid annulus and through the CT gap could result in double loop reentry (n = 12). After successful ablation of the cavotricuspid isthmus (CTI) in 24 patients, upper loop reentry was still induced in 12 patients with double loop reentry. Subsequent ablation of the CT gap was performed successfully in these 12 patients, and no arrhythmia was inducible thereafter. During the follow-up period of 8.4 ± 4.1 months, there was no recurrence of atrial flutter in any patient. Conclusion: During typical atrial flutter, the CT might be an incomplete barrier. Simultaneous conduction through the CTI and CT gap could result in double loop reentry. Radiofrequency ablation of the CTI and CT gap was effective in eliminating this arrhythmia. (J Cardiovasc Electrophysiol, Vol. 15, pp. 406-414, April 2004) [ABSTRACT FROM AUTHOR]

LEE, P.-C., et al.: Effects of a Blocked Atrial Beat on the Atrioventricular Nodal Recovery Property in Patients with Dual Nodal Pathways. Dual AVN physiology can be demonstrated by a variety of maneuvers. To determine whether AVN recovery times following a blocked extrastimulus facilitate or obscure detection of dual AVN physiology, 11 patients (9–17 years) were studied with dual AVN pathways by using single and double atrial extrastimuli. With a single atrial extrastimuli, the premature atrial stimulus (A2) was coupled to basic atrial beats (A1). The fast and slow AVN recovery curves were constructed with plots of the nodal conduction time against the recovery time (A1A2,A2H2). With double atrial extrastimuli, a fixed blocked A2 beat (A2B) was followed by a scanning atrial beat (A3). The nodal recovery property post-A2B was studied by plots of A2BA3,A3H3. In all patients the recovery curve of the fast pathway post-A2B had a leftward shift when compared to that of the pre-A2B curve (i.e., the AH was shortened at the same recovery time). The window of slow pathway conduction post-A2B disappeared totally in five patients and decreased significatly in six patients (post-A2B: 26 ± 42 ms; pre-A2B: 80 ± 65 ms, P < 0.05). In the six patients that still had slow pathway conduction post-A2B, the slow pathway effective refractory period post-A2B was significantly less than that of pre-A2B (215 ± 38 vs 268 ± 16 ms, P < 0.05). The fast pathway effective refractory period post-A2B was also diminished significantly (235 ± 62 vs 357 ± 76 ms, P < 0.0001). The authors conclude that blocked atrial beats decrease the visibility of the slow pathway conduction. (PACE 2003; 26:2091–2095) [ABSTRACT FROM AUTHOR]

Abstract: Renovascular disease is an important cause of secondary hypertension in children. In contrary to the adult patients whose major cause of renal artery stenosis (RAS) is atherosclerosis, fibromuscular dysplasia is responsible for the renovascular hypertension in most children. Mid-aortic syndrome (MAS) is a rare abnormality referring to an isolated disease of the distal thoracic and abdominal aorta resulting in significant tubular narrowing with stenosis of the visceral and renal arteries. It is usually diagnosed in young adults, but may present in childhood as a challenging problem. Patients with MAS are often first detected due to refractory hypertension. Other later presentations include intermittent claudication, congestive heart failure, renal insufficiency and symptoms of hypertensive associated end-organ damage. We report a case of a 16-year-old patient with MAS who suffered from malignant arterial hypertension. A percutaneous transluminal renal angioplasty (PTRA) was first performed, however the stenosis proved resistant to dilatation and only resulted in a minimal angiographic improvement. Due to persistent hypertension, an aortorenal bypass using the saphenous vein was performed. We also reviewed the literature on PTRA and the surgical management of RAS in MAS patients, in which PTRA often carries poor results. [Copyright &y& Elsevier]

This study was aimed at evaluating the efficacy of non-contact mapping and ablation of non-incisional atypical right atrial (RA) flutters.The majority of atypical RA flutters were reported in patients after surgical incision of the RA.The study group consisted of 15 patients (61 ± 13 years, 8 males) with atypical atrial flutter (AFL). The RA activation during AFL was delineated using a non-contact mapping system (EnSite 3000 with Precision Software, Endocardial Solutions, St. Paul, Minnesota). The narrowest part of each reentrant circuit was targeted using radiofrequency energy.In all 15 patients, non-contact mapping showed AFLs confined to the RA with RA activation time accounting for 100% of the cycle length (210 ± 19 ms). During single-loop re-entry in seven patients, the activation wave front circulated around the central obstacle (CO) in the anterolateral wall with conduction through the channel between the CO and the crista terminalis (CT). During figure-of-eight re-entry in eight patients, simultaneous upper and lower loop re-entry through the conduction gap in the CT was found in four patients, and simultaneous upper loop and free-wall single-loop re-entry was observed in four patients. Radiofrequency ablation of the free-wall channel and/or CT gap was effective in eliminating these AFLs in 13 patients. During a follow-up of 16.8 ± 3.8 months, two patients had recurrence of left AFL, and one had recurrence of atrial fibrillation.Atypical RA flutters could arise from single-loop or double-loop figure-of-eight re-entry. Radiofrequency ablation of the free-wall channel and/or the CT gap was effective in eliminating these arrhythmias. [Copyright &y& Elsevier]