A case report of delayed diagnosis of danon disease: Caused by a newly recognized mutation in the lysosome-associated membrane protein-2 gene

INTRODUCTION

Danon disease is a rare X-linked dominant genetic disorder caused by defects in the lysosome-associated membrane protein 2 (LAMP2) gene. Unless treated, cardiogenic death is the main cause of mortality. This case report describes a 19-year-old man who was diagnosed with Danon disease and survived for 3 years from symptom onset to death. The mutation in his LAMP2 gene (p.Gly221Ilefs*19) had not been previously reported.

PATIENT CONCERNS

A 19-year-old man patient was hospitalized for intermittent palpitations. He had no family history of cardiomyopathy, arrhythmia, or sudden cardiac death, but his sister had died of cirrhosis at age 12 years, but the exact cause of cirrhosis was unknown.

DIAGNOSIS

Exome sequencing and Sanger sequencing identified a novel missense mutation (p.Gly221Ilefs*19) in the LAMP2 gene of the proband. This mutation was also detected in his mother, confirming the diagnosis of Danon disease.

INTERVENTIONS

The patient experienced various types of arrhythmia throughout the clinical process, including Wolff-Parkinson-White syndrome, non-sustained atrial tachycardia, atrial flutter, and third-degree atrioventricular block. He was therefore treated with cardiac ablation procedures and cardiac resynchronization therapy.

OUTCOMES

The period from the onset of symptoms to the onset of heart failure was 2 years. The patient died of cardiogenic death during the third year, at age 22 years.

LESSONS

Danon disease is a rare disease that is difficult to recognize because of its hidden early manifestations. Early identification of its clinical symptoms can lead to early diagnosis and treatment.

Management of Asymptomatic Wolff-Parkinson-White Pattern in Young Patients: Has Anything Changed?

The approach to pediatric asymptomatic Wolff-Parkinson-White (WPW) patients is controversial. The objective of this review is to update the last consensus of specialists of the Pediatric and Congenital Electrophysiology Society/Heart Rhythm Society on this subject in order to summarize the most recent evidence on the management of young patients with asymptomatic WPW pattern. A systematic review of the literature published between 2008 and 2018 was performed taking into account the protocol of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) in PubMed (including Cochrane), Embase, and Web of Science. Observational, experimental, and multicentric studies were included. Out of a total of 37 articles selected, 4 were considered eligible. Most studies considered a cutoff age of 8 or greater as recommended in the 2012 consensus. The identification of a shortest pre-excitatory RR interval (SPERRI) ≤ 250 ms seems to be the best predictor for risk stratification. The importance of routine isoprenaline use to improve the sensitivity of the electrophysiological study to identify patients at high risk of sudden death was consensual. Prophylactic ablative therapy has been indicated in asymptomatic children with an accessory pathway (AP) who have a low SPERRI and/or a low effective anterograde period of the AP and/or multiple APs. Despite the evidence found in the most recent studies, more studies are warranted in this setting.

Cardiac electrophysiologic procedures - A ten years' experience at National Institute of Cardiovascular Diseases, Karachi

OBJECTIVE

To review 10 years of clinical practice of cardiac electrophysiology study and radiofrequency catheter ablation in the treatment of supraventricular tachycardia.

METHODS

The retrospective chart review was conducted at the National Institute of Cardiovascular Diseases, Karachi, and comprised records of all patients who underwent electrophysiological study and / or radiofrequency catheter ablation from January2007 to December 2016. SPSS 21 was used for data analysis.

RESULTS

Of the 627 patients, 335(53.4%) were females. The overall mean age was 40.99}13.59 years. The major indication for procedure was supraventricular tachycardia 376(59.97%). Final electrophysiological study diagnosis was typical slow fast atrioventricular nodal re-entrant tachycardia in 303(48.3%) patients. The overall success rate was 472(75.3%). Procedure-related complications were reported in 25(4%) patients, and there was 1(0.15%) mortality.

CONCLUSIONS

Cardiac electrophysiology studies and radiofrequency catheter ablation were found to be an effective and safe method for diagnosis and treatment of supraventricular tachycardia.

Prognostic Significance and Risk of Atrial Fibrillation of Wolff-Parkinson-White Syndrome in Patients With Hypertrophic Cardiomyopathy

To assess the mid-term mortality and risk of atrial fibrillation (AF) in patients with hypertrophic cardiomyopathy (HC) and Wolff-Parkinson-White (WPW) syndrome, 40 patients with HC and WPW were enrolled in our center between 2010 and 2017. An age- and gender-matched comparison cohort of patients with HC without WPW (n = 160) was generated from the same center. The clinical profile and outcomes were assessed. Of 40 patients with WPW, 28 underwent accessory pathway (AP) elimination. Two patients (7%) had failed in AP elimination. During mid-term follow-up, 1 patient had an implantable cardioverter-defibrillator intervention. Fourteen patients had AF. A previous history of AF (hazard ratio [HR]: 4.69; 95% confidence interval [CI] 1.51 to 14.63) and left atrial dimension (HR: 1.12; 95% CI 1.03 to 1.23) at baseline were risk factors for AF occurrence during follow-up. The AP elimination significantly reduced risk for the incidence of AF (HR: 0.22; 95% CI 0.06 to 0.83). Compared with the control group, the prevalence of syncope and AF were significantly higher in the WPW group. During follow-up, no difference was identified in outcome measures consisting of all-cause death, cardiac transplantation, and implantable cardioverter-defibrillator intervention. A previous history of AF (HR: 5.20; 95% CI 2.63 to 10.30, p <0.001) and persistent existing WPW (HR: 3.64; 95% CI 1.63 to 8.11, p = 0.002) were independent risk factors for AF occurrence during follow-up in the entire cohort. In conclusion, although WPW was uncommon and might not be correlated with mid-term mortality in HC patients, WPW might increase the risk of AF occurrence. Additionally, AP elimination may reduce the risk of AF occurrence.

Papillary Muscle Rupture in an Adolescent with No Coronary Lesions

A 21-year-old man with Wolff-Parkinson-White syndrome presented to the authors' hospital with ventricular fibrillation. Coronary angiography failed to demonstrate coronary stenosis, but temporary mechanical circulatory support resolved the ventricular fibrillation and the patient was extubated eight days later. On the next day, however, he had to be re-intubated with symptoms of congestive heart failure. Echocardiography revealed new severe mitral regurgitation and a mobile mass, while emergency surgery revealed a posteromedial papillary muscle rupture (PMR). The mitral regurgitation was repaired with ruptured papillary muscle relocation, artificial chordae implantation, and ring annuloplasty. Postoperative examinations suggested that an arrhythmia-induced coronary circulation hypoperfusion and septic embolization had caused the PMR.

[AV-reentrant tachycardia and Wolff-Parkinson-White syndrome : Diagnosis and treatment]

The AV-reentrant tachycardia (AVRT) is a supraventricular tachycardia with an incidence of 1-3/1000. The pathophysiological basis is an accessory atrioventricular pathway (AP). Patients with AVRT typically present with palpitations, an on-off characteristic, anxiety, dyspnea, and polyuria. This type of tachycardia may often be terminated by vagal maneuvers. Although the clinical presentation of AVRT is quite similar to AV-nodal reentrant tachycardias, the correct diagnosis is often facilitated by analyzing a standard 12-lead ECG at normal heart rate showing ventricular preexcitation. Curative catheter ablation of the AP represents the therapy of choice in symptomatic patients. This article is the fourth part of a series written to improve the professional education of young electrophysiologists. It explains pathophysiology, symptoms, and electrophysiological findings of an invasive EP study. It focusses on mapping and ablation of accessory pathways.

Genome editing with CRISPR/Cas9 in postnatal mice corrects PRKAG2 cardiac syndrome

PRKAG2 cardiac syndrome is an autosomal dominant inherited disease resulted from mutations in the PRKAG2 gene that encodes γ2 regulatory subunit of AMP-activated protein kinase. Affected patients usually develop ventricular tachyarrhythmia and experience progressive heart failure that is refractory to medical treatment and requires cardiac transplantation. In this study, we identify a H530R mutation in PRKAG2 from patients with familial Wolff-Parkinson-White syndrome. By generating H530R PRKAG2 transgenic and knock-in mice, we show that both models recapitulate human symptoms including cardiac hypertrophy and glycogen storage, confirming that the H530R mutation is causally related to PRKAG2 cardiac syndrome. We further combine adeno-associated virus-9 (AAV9) and the CRISPR/Cas9 gene-editing system to disrupt the mutant PRKAG2 allele encoding H530R while leaving the wild-type allele intact. A single systemic injection of AAV9-Cas9/sgRNA at postnatal day 4 or day 42 substantially restores the morphology and function of the heart in H530R PRKAG2 transgenic and knock-in mice. Together, our work suggests that in vivo CRISPR/Cas9 genome editing is an effective tool in the treatment of PRKAG2 cardiac syndrome and other dominant inherited cardiac diseases by selectively disrupting disease-causing mutations.

Prophylactic accessory-pathway ablation in asymptomatic patients with a Wolff-Parkinson-White electrocardiographic pattern

OBJECTIVES

The optimal approach is controversial in asymptomatic patients who are coincidentally found to have evidence of an accessory pathway (AP) on an ECG. The risk of sudden cardiac death (SCD) is low, and the risk of developing symptoms also appears to be low, although a wide range of incidences have been reported. In our trial, we tested the hypothesis that if prophylactic accessory-pathway ablation performed at the time of the initial electrophysiological testing would improve the long-term outcome in asymptomatic patients with a Wolff-Parkinson-White electrocardiographic pattern.

PATIENTS AND METHODS

Recruitment of patients began on February 1, 2004, and ended on February 5, 2009. All 110 asymptomatic patients were hospitalized and underwent electrophysiological testing the same day to assess the inducibility of atrioventricular reciprocating tachycardia. The anterograde effective refractory period of the accessory pathway was defined as the longest coupling interval at which anterograde block in the bypass tract was observed. For the statistical analysis, the statistical software SPSS version 15.0 for Windows (SPSS Inc., Chicago, IL, USA).

RESULTS

Of 110 asymptomatic patients with a Wolff-Parkinson-White electrocardiographic pattern, 80 patients were ablated. Ablation group consisted of these patients. Control group consisted of remaining 30 and were divided into two groups according to the anterograde effective refractory period of the accessory pathway. There was no significant difference between three groups in terms of arrhythmic events (p: 0.58).

CONCLUSIONS

Asymptomatic patients with the Wolff-Parkinson-White syndrome do not require prophylactic ablation, since they remain asymptomatic for many years.

Risk factors for maternal and fetal outcome in pregnancy complicated by Ebstein anomaly

OBJECTIVE

The goal of the study was to examine risks in pregnancy in patients with Ebstein anomaly.

STUDY DESIGN

Data were examined retrospectively for 13 patients (27 pregnancies, 21 live births) with Ebstein anomaly during pregnancy who were treated at our institution from 1985 to 2011. The associated anomalies in these patients were atrial septal defect (ASD) (n = 4) and the Wolff-Parkinson-White syndrome (n = 6).

RESULTS

Before pregnancy, 2 patients underwent ASD closure and 1 received tricuspid valve replacement (TVR). In all patients, the cardiothoracic ratio increased from 55.1 at conception to 57.0 during pregnancy and 58.0 postpartum (P < .05). Cesarean sections were performed in 3 cases: 1 with ventricular tachycardia and orthopnea (New York Heart Association [NYHA] III) preterm; at full term, and the third in a patient with a mechanical tricuspid valve who developed maternal cerebellum hemorrhage at 27 weeks. The baby died of prematurity in the third case. In all other cases (20 of 21), neonatal prognoses were good without congenital heart diseases. There were 6 spontaneous abortions. Recurrent paroxysmal supraventricular tachycardia occurred during pregnancy in 2 cases and was treated with adenosine triphosphate or verapamil. In 17 pregnancies, NYHA remained in class I and all had full-term vaginal delivery.

CONCLUSION

Maternal and fetal outcomes are good in patients with Ebstein anomaly and NYHA class I. However, pregnancy in Ebstein anomaly can be complicated with tachyarrhythmia or cardiac failure. In post-TVR cases, meticulous care is required for these complications during pregnancy and delivery.

A prospective, in vivo evaluation of two pressure-redistribution surfaces in healthy volunteers using pressure mapping as a quality control instrument 

Deep tissue injury (DTI) can rapidly evolve into a higher stage pressure ulcer. Use of pressure-redistribution surfaces is a widely accepted practice for the prevention of pressure ulcers in acute care patients, particularly in departments where care processes limit mobility. A 15-year-old patient developed a sacral DTI 24 hours after completion of a lengthy (12- hour) electrophysiology (EP) study and catheter ablation. A root cause analysis (RCA) conducted to investigate the origin of the hospital-acquired suspected DTI prompted a small investigation to evaluate the pressure-distribution properties of the EP lab surface and an OR table pad. Five healthy adult employee volunteers were evaluated in the supine position by placing a sensing mat between the volunteer and the test surface. Interface pressures (on a scale of 0 mm Hg to 100 mm Hg) were captured after a "settling in" time of 4 minutes, and the number of sensors registering very high pressures (above 90 mm Hg) across the surface were recorded. On the OR table pad, zero to six sensors registered >90 mm Hg compared to two to 20 sensors on the EP lab surface. These data, combined with the acquired DTI, initiated a change in EP lab surfaces. Although interface pressure measurements only provide information about one potential support surface characteristic, it can be helpful during an RCA. Studies to compare the effect of support surfaces in all hospital units on patient outcomes are needed.

[Evaluation of the radiofrequency ablation effectiveness in patients with the Wolff-Parkinson-White syndrome]

A one-year prospective study involved 22 patients with the Wolff-Parkinson-White syndrome (WPW) and 20 healthy people. Means age of patients was 34.3 +/- 16.3 years. All 22 patients were successfully treated with radiofrequency ablation (RFA) of additional pathways. RFA effectiveness was evaluated with the help of clinical questionnaire, data of ECG, EchoCG, heart rate variability (HRV), frequency response and nonlinear dynamics. Cardiac rhythm disturbances were verified using Holter monitoring applied to all patients. Positive clinical effect was achieved in all the WPW patients, as RFA arrested cardiac arrhythmias completely. Holter monitoring did not register cardiac disturbances which points to high RFA effectiveness in WPW patients. HRV, frequency response and nonlinear dynamics reassumed their normal patterns.

Wolff-Parkinson-White syndrome concomitant with idiopathic ventricular fibrillation associated with inferior early repolarization

We encountered a 39-year-old man with documented ventricular fibrillation (VF). His ECGs showed intermittent Wolff-Parkinson-White (WPW) syndrome pattern. During electrophysiological study, no ventricular preexcitation was observed. An accessory pathway located at the posterior mitral annulus was identified, and successfully eliminated by radiofrequency catheter ablation. VF was not induced. His ECGs in the absence of delta waves demonstrated early repolarization in the inferior leads. This case raises the possibility that patients with manifest WPW syndrome may have an arrhythmogenic substrate associated with early repolarization, and the characteristic J waves can be masked by the presence of ventricular preexcitation.

[Acute coronary syndrome during dissection of left main as a complication of radiofrequency ablation]

We present a case of 44 year-old female who was admitted to the hospital due to performed radio frequency ablation because of VF during WPW syndrome, which was complicated by dissection of left main. The dissection was treated with success by primary percutaneous coronary intervention with two metal stents.

Aberrant pathway in an anomaly: pre-excitation syndrome in association with coronary sinus aneurysm

Congenital coronary sinus anomalies are unusual and they rarely coexist with accessory atrio-ventricular pathways. These anomalies are generally symptomatic; however they can cause difficulty in mapping. The association between accessory pathway and coronary sinus anomalies may suggest an embryological link. Here, we report on a male patient with an accessory conducting pathway in the coronary sinus, leading to Wolff-Parkinson-White (WPW) syndrome.

Emergency treatment of Wolff-Parkinson-White syndrome

This article describes the aetiology of Wolff-Parkinson-White syndrome and discusses the benefits and disadvantages of some of the available cardioversion medications with which it can be treated.

[Echocardiographic parameters in patients with Wolf-Parkinson-White syndrome before and during one year after radiofrequency catheter ablation of accessory atrioventricular junction]

We present in this paper results of assessment of morphofunctional state of myocardium in patients with the Wolf-Parkinson-White syndrome before and during one year after radiofrequency catheter ablation (RFA) of accessory atrioventricular junction (AAVJ) and comparison of them with analogous parameters of the group of healthy volunteers as well as in dependence on electrophysiological properties of AAVJ and its localization. One hundred sixty patients took part in the conducted study: main group comprised 160 patients (80.7%) with WPW syndrome (114 men [81.4%], 26 women [18.6%], mean age 39.5+/-15.3 years), comparison group comprised 20 practically healthy persons (15 men [75.0%], 5 women [25%], mean age 41.9+/-5.3 years). All main group patients were subjected to endocardial electrophysiological investigation and RFA of AAVJ. Transthoracic echocardiography (EchoCG) was carried out in patients of main group before and in 2, 6, and 12 months after operation of RFA of AAVJ, and once in control group. Analysis of parameters of central hemodynamics according to data of transthoracic EchoCG in patients with WPW syndrome before RFA of AAVJ demonstrated that before conduct of operative intervention no significant differences were revealed in the studied parameters compared with analogous characteristics of the clinical comparison group. During whole period of dynamic observation (2, 6, and 12 months after fulfilled RFA of AAVJ) in patients with WPW syndrome the studied parameters of central hemodynamics did not undergo substantial changes compared with initial characteristics. We failed to establish significant differences of EchoCG parameters in patients with WPW syndrome in dependence on electrophysiological properties of AAVJ (concealed, manifest) and on AAVJ localization (right, left, septal). According to EchoCG data in patients with WPW syndrome so called "minor" anomalies of development of connective tissue of the heart were diagnosed in 69 (49.3%) patients while in control group - in 2 (10%) patients.

Contributions of the Instituto Nacional de Cardiología in the diagnosis and treatment of the Wolff-Parkinson - White syndrome

Since the first description of the disease now known as Wolff-Parkinson-White syndrome, much knowledge has been gained through several experimental and clinical studies all over the world. The Instituto Nacional de Cardiología Ignacio Chávez in Mexico City has not been the exception. In this report, we describe the clinical, electrocardiographic and electrophysiologic contributions of past and present researchers at the Institute, as well as the experience in the diagnosis and treatment of the W-P-W syndrome at this Instituto Nacional de Cardiología Ignacio Chávez.

Detection and quantification by deformation imaging of the functional impact of septal compared to free wall preexcitation in the Wolff-Parkinson-White syndrome

Pacing experiments in healthy animal hearts have suggested a larger detrimental effect of septal compared to free wall preexcitation. We investigated the intrinsic relation among the site of electrical preexcitation, mechanical dyssynchrony, and dysfunction in human patients. In 33 patients with Wolff-Parkinson-White (WPW) syndrome and 18 controls, regional myocardial deformation was assessed by speckle tracking mapping (ST-Map) to assess the preexcitation site, shortening sequences and dyssynchrony, and the extent of local and global ejecting shortening. The ST-Map data in patients with accessory atrioventricular pathways correctly diagnosed as located in the interventricular septum (IVS) (n = 11) or left ventricular free wall (LFW) (n = 12) were compared to the corresponding control values. A local ejecting shortening of <2 SD of the control values identified hypokinetic segments. The localization of the atrioventricular pathways by ST-Map matched with the invasive electrophysiology findings in 23 of 33 patients and was one segment different in 5 of 33 patients. In both WPW-IVS and WPW-LFW, local ejecting shortening was impaired at the preexcitation site (p <0.01). However, at similar electrical and mechanical dyssynchrony, WPW-IVS had more extensive hypokinesia than did WPW-LFW (3.6 +/- 0.9 vs 1.8 +/- 1.3 segments, p <0.01). Compared to controls, the left ventricular function was significantly reduced only in WPW-IVS (global ejecting shortening 17 +/- 2% vs 19 +/- 2%, p = 0.01; ejection fraction 55 +/- 5% vs 59 +/- 3%, p = 0.02). In conclusion, preexcitation is associated with local hypokinesia, which at comparable preexcitation is more extensive in WPW-IVS than in WPW-LFW and could adversely affect ventricular function. ST-Map might have a future role in detecting and guiding treatment of septal pathways with significant mechanical effects.

Wolff-Parkinson-White syndrome in infants

Wolff-Parkinson-White (WPW) syndrome is a ventricular preexcitation that presents as supraventricular tachycardia. Health care professionals can attain optimal results in caring for infants with WPW syndrome by understanding both its pathophysiology and proper management to prevent and treat complications associated with it. This article reviews the prevalence, pathophysiology, clinical manifestations, diagnostic modalities, assessment, and management of WPW syndrome.

[Wolff--Parkinson--White syndrome: classification, clinical manifestations, diagnosis, and treatment]

Main etiological factors, mechanisms of arrhythmogenesis, and classification of Wolff-Parkinson-White (WPW) syndrome are presented and clinico-electrocardiographical and electrophysiological peculiarities of atrioventricular reciprocal tachycardia in this syndrome are described. Main diagnostic measures, principles of their correct interpretation are specified and principles of tactical approach to management of patients are presented. Indications to electrophysiological investigation and radiofrequency catheter ablation, physical characteristics of radiofrequency action in regions of optimal mapping of supplementary atrioventricular junction are discussed. Data of analysis of efficacy of pharmacological and interventional approaches to the treatment of patients with WPW syndrome are also presented.

Management of atrial fibrillation--Part 2

Many cardiologists prefer, especially in older patients, ventricular rate control plus warfarin rather than maintaining sinus rhythm with anti-arrhythmic drugs. Patients with chronic or paroxysmal AF at high risk for stroke should be treated with long-term warfarin to achieve an International Normalized Ratio of 2.0 to 3.0. Patients with AF at low risk for stroke or with contraindications to warfarin should be treated with aspirin.

WPW and preexcitation syndromes

Wolff-Parkinson-White syndrome is a disorder characterized by presence of an accessory pathway which predisposes patients to tachyarrhythmias and sudden death. Among patients with WPW syndrome, atrioventricular reentrant tachycardia (AVRT) is the most common arrhythmia, accounting for 95% of re-entrant tachycardias. It has been estimated that one-third of patients with WPW syndrome have atrial fibrillation (AF). AF is a potentially life-threatening arrhythmia. If an accessory pathway has a short anterograde refractory period, then rapid repetitive conduction to the ventricles during AF can result in a rapid ventricular response with subsequent degeneration to ventricular fibrillation (VF). The accessory pathway may be located anywhere along the atrioventricular valve Most of the patients are young and do not have structural heart disease hence it is important to risk stratify these patients so as to prevent the sudden death. Management of asymptomatic patients with WPW syndrome has always remained controversial Catheter ablation of accessory pathways has become an established mode of therapy for symptomatic patients and asymptomatic patients employed in high-risk professions.

Aborted Sudden Cardiac Death Revealing Isolated Noncompaction of the Left Ventricle in a Patient with Wolff-Parkinson-White Syndrome

Isolated noncompaction of the left ventricle (INLV) is a rare congenital disorder associated with multiple cardiac arrhythmias. We report a case of INLV revealed by ventricular fibrillation in a patient with Wolff-Parkinson-White syndrome. Because of the persistence of inducible ventricular arrhythmias after ablation of the accessory pathway, implantation of an ICD was decided.

Modulation of the expression of long-term cardiac memory by short-term cardiac memory in patients with Wolff-Parkinson-White syndrome after catheter ablation

BACKGROUND

The interaction between long-and short-term cardiac memory (CM) is unknown.

METHODS AND RESULTS

The T-wave areas and QTc intervals in each ECG lead were analyzed in 11 patients with manifest Wolff-Parkinson-White syndrome with posterior or septal accessory pathway (4 females; mean age: 47+/-12 years) in the following ECGs: (1) immediately after catheter ablation (post-ablation ECG); (2) immediately after 20 min of right ventricular outlet pacing (post-pacing ECG); and (3) 1 week after ablation (recovery ECG). Compared with the post-ablation ECGs, the T-wave areas of the recovery ECGs in leads II and aV(F) changed dramatically from negative to positive while that in lead III became less negative (p<0.01), and those in leads I, aV(L), and V(2-4) became less positive (p<0.05). Compared with the post-ablation ECGs, the T-wave areas of the post-pacing ECGs in leads III and aV(F) became less negative (p<0.01), and those in leads I, aV(L), and V(2-4) became less positive (p<0.05). The QTc interval in the post-ablation ECG was significantly longer than in either the post-pacing or recovery ECGs (p<0.05).

CONCLUSIONS

Mechanisms involved in the expression of long-term CM could be affected by short-term CM.

Dynamic effects of exercise and different escape rhythms on the supernormal period of an accessory pathway

Spontaneous conduction during the supernormal period (SNP) of accessory pathways (AP) is rare and observed only during atrio-ventricular block (AVB). The effect of exercise and different escape rhythms on the SNP is unknown. We evaluated these factors on the SNP of a para-Hisian AP after a failed ablation complicated by AVB. The SNP onset and duration were later and longer during paced versus junctional rhythm. Exercise caused linear shortening of the SNP that was directly related to junctional cycle length. The SNP is a dynamic window shifting in parallel with AP refractoriness and affected by exercise and type of escape rhythm.

Successful outcome in a pregnant woman with isolated noncompaction of the left ventricular myocardium

A 24-year-old pregnant woman was referred to our hospital for the evaluation of her cardiac function. An electrocardiogram showed Wolff-Parkinson-White syndrome. Echocardiography revealed prominent trabeculation and deep intertrabecular recesses at the left ventricular apex and mid-portion of the inferior and lateral wall, with an impaired ejection fraction. She was diagnosed as having an isolated noncompaction of the ventricular myocardium (INVM). As the pregnancy progressed, severe restrictive hemodynamics became apparent. In consideration of the fetal growth, we decided to deliver the fetus by cesarean section at 32 weeks gestation; the patient successfully delivered a female infant. Interestingly, echocardiography demonstrated INVM in both the child and mother. This report is the first description of a successful pregnancy in a patient with familial INVM.

Risk stratification in the asymptomatic child with Wolff–Parkinson–White syndrome

PURPOSE OF REVIEW

As the safety and efficacy of invasive electrophysiologic studies and ablation therapy in pediatrics improves, there has been a greater interest in developing adequate risk stratification criteria for the asymptomatic pediatric patient with Wolff-Parkinson-White syndrome. This review will discuss the recent literature regarding this debate.

RECENT FINDINGS

Recent retrospective and prospective studies of Wolff-Parkinson-White syndrome in asymptomatic pediatric patients have shown that the well established adult criteria for risk stratification may not be applicable in children. Both symptomatic and asymptomatic children had similar accessory pathway effective refractory periods and supraventricular tachycardia inducibility in recent invasive electrophysiologic studies. The first attempt at prospective evaluation of the use of ablation therapy in asymptomatic adult and pediatric patients with the condition has sparked a debate as to the definition of a high-risk patient and the utility of ablation in the asymptomatic patient.

SUMMARY

It is still controversial whether the established criteria for risk stratification in adults can be confidently applied to the pediatric patient. The majority of pediatric electrophysiologists use invasive electrophysiologic studies for risk stratification and selection of appropriate therapy. This clinical practice reflects the increasing prevalence and safety of electrophysiologic study and ablation. Further studies to better define indications for study and ablation are still necessary, however, to define accurate criteria for risk stratification in this difficult pediatric problem.

Sensibility analysis of the Arruda localization method

This paper presents an analysis of the Arruda accessory pathway localization method (for patients suffering from Wolff-Parkinson-White syndrome) with suggestions to increase the overall performance. The Arruda method was tested on a total of 121 patients, and a 90% localization performance was reached. This was considered almost as performing result as the highest published (90%) by L. Boersma in 2002. After a deeper analysis of each decision point of Arruda localization method we considered that the lead AVF is not as relevant as other used leads (I, II, III, VI). The overall performance (90%) was slightly lower then the correct decision rate (91.67%) at the weakest decision element (AVF+) of the method. The vectorial space constructed from the most used leads (II, VI, AVF) is not orthogonal which can be a reason for weaker rate in case of AVF.

Pediatric Radiofrequency Catheter Ablation Sedation Methods and Success, Complication and Recurrence Rates

BACKGROUND

There remains to be issues regarding radiofrequency catheter ablation (RFCA) in pediatric patients that are different to those involving adults. This study was performed to determine the efficacy and safety of RFCA in pediatric patients.

METHODS AND RESULTS

During the period from 1992 to 2003, 2,734 patients underwent RFCA and 131 pediatric patients who were < or =15 years old (70 males, mean age 12.0+/-3.1 years) were analyzed, retrospectively. The number of accessory pathways (APs) mediating atrioventricular re-entrant tachycardia was 93 (71.4%) and atrioventricular nodal re-entrant tachycardia (AVNRT) was 27 (20.5%). The most common indications for the RFCA were the ;patient's choice' in 94 (71.2%) and 'medically refractory tachycardia' in 29 (22.0%). The age-related indication of the ;patient's choice' was 80.4% (82 of 102) for those >10 years old and 40.0% (12 of 30) for those < or =10 years old (p=0.01). RFCA was performed without sedation in 87.3% (89 of 102) of the subjects >10 years old as compared to 20.0% (6 of 30) of those < or =10 years old (p=0.01). The success rate was 92.8% (90 of 97 APs) for the ablation of APs, and 96.3% (26 of 27) for that of AVNRT. The overall complication rate was 3.8% (5 of 131). During a mean follow-up duration of 13.1+/-2.5 months, the freedom of recurrence was 87.8% (79 of 90) for the arrhythmia associated with APs and 92.3% (24 of 26) for AVNRT.

CONCLUSION

RFCA in pediatric patients had a good success rate with acceptable recurrence and complication rates when compared to adult patient results. Therefore, RFCA could be considered as the first line of therapy for arrhythmias with concealed and manifested APs and AVNRT in pediatric patients.

Progressive facilitation of antegrade conduction via an accessory pathway in a patient with Wolff-Parkinson-White syndrome and permanent atrial fibrillation

The case of a 64-year-old man with Wolff-Parkinson-White syndrome and permanent atrial fibrillation (AF) is reported. The patient was admitted due to electrocardiographic feature of AF with rapid conduction over the left-sided accessory pathway. Administration of pirmenol effectively suppressed the ventricular response via an accessory pathway. A transesophageal echocardiography detected an uncertain thrombus in the left atrial appendage. During the 33-month follow-up period, the ventricular response via an accessory pathway was progressively facilitated. Radiofrequency catheter ablation using a transseptal approach was performed during AF, resulting in complete elimination of the antegrade accessory pathway conduction.