Clinical features of Wolff-Parkinson-White syndrome

Utility of Intracoronary Acetylcholine Provocation Testing in Inducing Atrial Fibrillation with Preexcitation Followed by Ventricular Fibrillation in a Patient with Wolff-Parkinson-White Syndrome

A 20-year-old man was resuscitated after ventricular fibrillation (VF). Electrocardiography revealed Wolff-Parkinson-White (WPW) syndrome. Intracoronary acetylcholine provocation (ACH test) testing was performed to induce VF secondary to the coronary vasospasm. The administration of acetylcholine to the coronary artery induced atrial fibrillation (AF) with preexcitation, followed by VF without coronary vasospasm. Electrophysiological studies revealed an accessory pathway managed by catheter ablation. Subsequent intracoronary ACH test induced the occurrence of AF without preexcitation. To our knowledge, this case report is the first to demonstrate the utility of the ACH test in confirming WPW syndrome as a cause of VF.

Anesthetic Management of a Patient With Wolff-Parkinson-White Syndrome Undergoing Gynecological Robotic Surgery

Robotic surgery provides precision and safety for minimally invasive gynecological operations but introduces unique anesthetic challenges, especially for individuals with pre-existing conditions like Wolff-Parkinson-White (WPW) syndrome. This case report addresses the anesthetic management of a 32-year-old female with WPW syndrome undergoing a myomectomy. A thorough pre-operative evaluation, including an ECG, echocardiogram, and Holter monitoring, was performed to assess the anesthetic and cardiac risks. The patient was administered a combination of loco-regional and general anesthesia, with an emphasis on neuromuscular monitoring, antiarrhythmic preparedness, and pain management to effectively manage the complexities introduced by WPW syndrome and robotic surgery. The anesthetic protocol comprised premedication with midazolam, induction using sufentanil, propofol, and rocuronium, and maintenance with desflurane, along with techniques to mitigate the effects of pneumoperitoneum and Trendelenburg positioning. Employing these strategies, the surgery concluded successfully without any anesthetic or surgical complications. The patient experienced a rapid and complete awakening, achieved optimal pain control, and was able to mobilize early, leading to her discharge 24 hours post-surgery. This case demonstrates the essential nature of customized anesthetic management for patients with WPW syndrome undergoing robotic surgery. It underscores the necessity of an exhaustive pre-operative assessment, diligent intraoperative monitoring, and active postoperative care to ensure patient safety and promote swift recovery.

Risk assessment in patients with symptomatic and asymptomatic pre-excitation

AIMS

Controversy remains as to whether the exercise stress test (EST) is sufficient for risk evaluation in patients with pre-excitation. This study aims to clarify the usefulness of EST in risk stratification in both asymptomatic and symptomatic patients presenting with pre-excitation.

METHODS AND RESULTS

This prospective study includes consecutive asymptomatic and symptomatic patients with pre-excitation referred for risk assessment. All participants performed an incremental EST (bicycle) prior to an electrophysiology study (EPS). Primary data from the EST included loss of pre-excitation during exercise, and primary data from the EPS included the measurement of accessory pathway effective refractory period (APERP), shortest pre-excited RR interval (SPERRI), and inducible arrhythmia with the use of a beta-adrenergic receptor agonist if deemed necessary. One hundred and sixty-four patients (59 asymptomatic, 105 symptomatic) completed an EST and EPS. Forty-five patients (27%) demonstrated low-risk findings on EST, of which 19 were asymptomatic and 26 were symptomatic. Six patients with low-risk EST findings had SPERRI/APERP ≤ 250 ms at EPS, and two of them were asymptomatic. The sensitivity, specificity, positive predictive value, negative predictive value (NPV), and accuracy of low-risk EST for excluding patients with SPERRI/APERP ≤ 250 ms were 40, 91, 87, 51, and 60%, respectively. The number of patients with inducible arrhythmia at EPS was similar in the asymptomatic (36, 69%) and symptomatic (73, 61%) groups.

CONCLUSION

Sudden loss of pre-excitation during EST has a low NPV in excluding high-risk APs. The EPS with the use of isoproterenol should be considered to accurately assess the risk of patients with pre-excitation regardless of symptoms (ClinicalTrials.gov Identifier: NCT03301935).

Wolf-Parkinson-White Syndrome: Diagnosis, Risk Assessment, and Therapy-An Update

Wolf-Parkinson-White (WPW) syndrome is a disorder characterized by the presence of at least one accessory pathway (AP) that can predispose people to atrial/ventricular tachyarrhythmias and even sudden cardiac death. It is the second most common cause of paroxysmal supraventricular tachycardia in most parts of the world, affecting about 0.1-0.3% of the general population. Most patients with WPW syndrome have normal anatomy, but it may be associated with concomitant congenital heart disease or systemic diseases. Although many individuals are asymptomatic, during supraventricular arrhythmia episodes, they may experience severe symptoms, including syncope or even sudden cardiac death (mainly due to pre-excited atrial fibrillation over rapidly conducting AP). In addition to arrhythmia-related symptoms, for some specific locations of the APs with overt anterograde conduction, there might be a reduction in exercise capacity mediated by a reduction in LV systolic performance due to anomalous LV depolarization. Although it is typically diagnosed through electrocardiography (ECG), additional tests are necessary for risk assessment. Management of WPW syndrome may be quite challenging and can vary from only acknowledging the presence of the accessory pathway to pharmacological treatment or radiofrequency ablation. Early diagnosis, risk assessment, and appropriate treatment are critical steps in the management of WPW syndrome, aiming to improve the quality of life and reduce the risk of life-threatening arrhythmias.

Broad Electrocardiogram Syndromes Spectrum: From Common Emergencies to Particular Electrical Heart Disorders

Electrocardiogram (ECG) still remains a very useful diagnostic method in modern cardiology. Its broad availability, noninvasiveness and good sensitivity explain why it plays a capital role in the very beginning of the process of diagnosis for every patient, with or without cardiac-related complaints. For the practitioner, good training in ECG interpretation is mandatory. Sometimes, the ECG trace reveals particular aspects that may cause confusion and complicate decision-making. In this article, we present several less common situations underlying the general context and ECG features. The syndromes studied have a high pathological significance and may range from acute emergencies that call for a rapid therapeutical response to chronic syndromes that require prolonged observation, monitoring and risk stratification.

Rapid Atrial Fibrillation in the Emergency Department

Atrial fibrillation (AF) is the most common rhythm disorder seen in doctors' offices and emergency departments (EDs). In both settings, an AF holistic pathway including anticoagulation or stroke avoidance, better symptom management, and cardiovascular and comorbidity optimization should be followed. However, other considerations need to be assessed in the ED, such as haemodynamic instability, the onset of AF, the presence of acute heart failure and pre-excitation. Although the Advanced Cardiovascular Life Support guidelines (European Society of Cardiology guidelines, Acute Cardiac Care Association/European Heart Rhythm Association position statements) and several recent AF publications have greatly assisted physicians in treating AF with rapid ventricular response in the ED, further practical clinical guidance is required to improve physicians' skill and knowledge in providing the best treatment for patients. Herein, we combine multiple strategies with supporting evidence-based treatment and experiences encountered in clinical practice into practical stepwise approaches. We hope that the stepwise algorithm may assist residents and physicians in managing AF in the ED.

Successful risk stratification of a patient with ventricular preexcitation by improved transesophageal electrophysiological study

The patient is a 19 years‐old man who often wakes up in dreams with palpitations and fatigue. The ECG shows: 1. Sinus rhythm; 2. Preexcitation syndrome. Transesophageal electrophysiological study (TEEPS) diagnosis:High‐risk accessory pathway. During radiofrequency catheter ablation, the patient suddenly developed atrial fibrillation and quickly converted to ventricular fibrillation. After defibrillation, ventricular fibrillation is transformed into sinus rhythm. Subsequently, the patient's high‐risk accessory pathway was successfully ablated. Studies have shown that about 25% of patients with WPW syndrome have a refractory period of less than 250 ms, which is one of the risk factors for the conversion of atrial fibrillation to ventricular fibrillation. Therefore, risk stratification is recommended for these symptomatic patients. From 1980 to 1990, there were literature reports on risk stratification of patients with preexcitation syndrome by TEEPS. But it has not become a routine examination of risk stratification in patients with preexcitation syndrome.The reason may be related to the hardware conditions and risk stratification methods used at that time. The TEEPS equipment currently used in our hospital can control the pacing voltage at about 12 mv on average. The voltage in this case report is 9 mv only. In addition, we successfully stratified the risk of patient with preexcitation syndrome without inducing atrial fibrillation. All the electrophysiological records of the patient during the examination were recorded simultaneously with the 12‐lead ECG and the esophageal lead ECG. These improvements makes TEEPS a simple, safe and reliable non‐invasive cardiac electrophysiological detection technology, which is worth popularizing in hospitals.

Infraclavicular Brachial Plexus Block and Sugammadex Use in a Paediatric Patient with Wolff-Parkinson--White Syndrome

Background

Wolff–Parkinson–White (WPW) syndrome is a rare disease that can cause various patterns of tachyarrhythmias. The main goal of anaesthesiologists for the perioperative anaesthetic management of WPW patients must be to avoid sympathetic stimulation and prevent tachyarrhythmias.

Case

A 9-year-old male patient with a diagnosis of WPW syndrome, who underwent emergency surgery for supracondylar humerus fracture, is presented. General anaesthesia in combination with infraclavicular brachial plexus (ICBP) block was performed successfully without any complications. For the reversal of neuromuscular block, sugammadex was uneventfully used. Intraoperative sympathetic discharge due to surgical intervention was prevented with ICBP block. The ICBP block has also provided good postoperative analgesia.

Conclusions

Sugammadex is a good alternative for the reversal of neuromuscular blocks to avoid the undesirable effects of cholinergic drugs. Peripheral regional blocks that require relatively large doses of local anaesthetics can be safely performed with utmost attention in paediatric WPW patients.

Perioperative management of patients with pre-excitation syndromes

Patients with pre-excitation abnormalities are at a high risk for life-threatening perioperative arrhythmias. In Wolff-Parkinson-White syndrome, the anaesthetics used for invasive diagnostic testing/ablation, should not affect cardiac electrophysiology; propofol, sevoflurane, fentanyl, sufentanil, alfentanil are suitable. In non-ablative surgery, propofol, sevoflurane, isoflurane, fentanyl, alfentanil, sufentanil have been used safely. Among neuromuscular blockers, cis-atracurium, rocuronium and vecuronium are good choices. Ketamine, pancuronium and pethidine should be avoided because of their sympathomimetic actions. Anticholinergic/ anticholinesterase combinations for neuromuscular block reversal should preferably be omitted, while sugammadex seems more attractive. In regional anaesthesia, addition of epinephrine and high sympathetic blocks should be avoided. Hypotension should be treated with pure alpha-adrenergic agonists. Other pre-excitation abnormalities associated with different accessory pathways are the Mahaim Fiber and Lown-Ganong-Levine syndrome. Sympathetic activation should be avoided. Total intravenous anaesthesia with propofol probably represents the safest option. A careful anaesthetic plan and close cooperation with cardiologists are mandatory for successful management.

Molecular Pathogenesis of Familial Wolff-Parkinson-White Syndrome

Familial Wolff-Parkinson-White (WPW) syndrome is an autosomal dominant inherited disease and consists of a small percentage of WPW syndrome which exhibits ventricular pre-excitation by development of accessory atrioventricular pathway. A series of mutations in PRKAG2 gene encoding gamma2 subunit of 5'AMP-activated protein kinase (AMPK) has been identified as the cause of familial WPW syndrome. AMPK is one of the most important metabolic regulators of carbohydrates and lipids in many types of tissues including cardiac and skeletal muscles. Patients and animals with the mutation in PRKAG2 gene exhibit aberrant atrioventricular conduction associated with cardiac glycogen overload. Recent studies have revealed "novel" significance of canonical pathways leading to glycogen synthesis and provided us profound insights into molecular mechanism of the regulation of glycogen metabolism by AMPK. This review focuses on the molecular basis of the pathogenesis of cardiac abnormality due to PRKAG2 mutation and will provide current overviews of the mechanism of glycogen regulation by AMPK. J. Med. Invest. 65:1-8, February, 2018.

Electrocardiography in athletes: normal and abnormal findings

Many sporting organisations recommend a pre-participation ECG to screen for disorders which predispose to sudden cardiac arrest (SCA). The ability of the ECG to perform accurately is dependent on the ECG criteria used and the experience of the operator. There have been several ECG criteria over the last decade, though these were recently superseded with the publication of the 'International Consensus Criteria for ECG Interpretation in Athletes'. These criteria use the latest evidence to improve specificity while maintaining sensitivity for ECG-detectable pathologies associated with SCA. Accordingly, this review describes the normal, borderline and abnormal ECG findings in an asymptomatic athlete aged 12-35 years.

When a Pseudo-Infarct Electrocardiogram (ECG) Pattern in a Posterior Accessory (Wolff-Parkinson-White) Pathway Masks a True Inferior Infarct

BACKGROUND Wolff-Parkinson-White (WPW) pattern is due to a pre-excitation leading to characteristic ECG changes in sinus rhythm as short PR interval, the presence of delta waves, wide QRS complexes, and potentially Q wave-T wave vector discordance (pseudo-infarct pattern). These later changes can mask the underlying ECG depolarizing solely through the His-Purkinje system. Our case highlights how the ECG of a WPW pattern with a pseudo-infarct pattern can in fact mask a true infarct on the underlying ECG without pre-excitation. CASE REPORT A 61-year-old diabetic man with a recent history of supra-ventricular tachycardia (SVT) presented with the ECG characteristic of a Wolff-Parkinson-White pattern i-e short PR interval of 0.10 s (<0.12 s) and the presence of delta waves in sinus rhythm. In addition, there was a wide significant Q wave in the inferior leads meeting the criteria for significant and pathologic Q waves, related to the pre-excitation and known as a pseudo-infarct pattern. The patient underwent successful ablation of his left inferoseptal accessory pathway. The pre-excitation pattern (short PR and delta wave) disappeared after successful ablation revealed a narrower Q wave in inferior leads, likely from unexpected true old inferior infarction, which was later confirmed by 2D echocardiogram and nuclear stress test (fixed inferior defect). CONCLUSIONS The presence of pseudo-infarct pattern due to a WPW does not always preclude the presence of underlying true infarct pattern, especially in the presence of coronary artery disease risk factors.

Risk Stratification for Arrhythmic Events in Patients With Asymptomatic Pre-Excitation: A Systematic Review for the 2015 ACC/AHA/HRS Guideline for the Management of Adult Patients With Supraventricular Tachycardia

Objective—

To review the literature systematically to determine whether noninvasive or invasive risk stratification, such as with an electrophysiological study of patients with asymptomatic pre-excitation, reduces the risk of arrhythmic events and improves patient outcomes.

Methods—

PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials (all January 1, 1970, through August 31, 2014) were searched for randomized controlled trials and cohort studies examining noninvasive or invasive risk stratification in patients with asymptomatic pre-excitation. Studies were rejected for low-quality design or the lack of an outcome, population, intervention, or comparator of interest or if they were written in a language other than English.

Results—

Of 778 citations found, 9 studies met all the eligibility criteria and were included in this paper. Of the 9 studies, 1 had a dual design—a randomized controlled trial of ablation versus no ablation in 76 patients and an uncontrolled prospective cohort of 148 additional patients—and 8 were uncontrolled prospective cohort studies (n=1594). In studies reporting a mean age, the range was 32 to 50 years, and in studies reporting a median age, the range was 19 to 36 years. The majority of patients were male (range, 50% to 74%), and <10% had structural heart disease. In the randomized controlled trial component of the dual-design study, the 5-year Kaplan-Meier estimates of the incidence of arrhythmic events were 7% among patients who underwent ablation and 77% among patients who did not undergo ablation (relative risk reduction: 0.08; 95% confidence interval: 0.02 to 0.33; P <0.001). In the observational cohorts of asymptomatic patients who did not undergo catheter ablation (n=883, with follow-up ranging from 8 to 96 months), regular supraventricular tachycardia or benign atrial fibrillation (shortest RR interval >250 ms) developed in 0% to 16%, malignant atrial fibrillation (shortest RR interval ≤250 ms) in 0% to 9%, and ventricular fibrillation in 0% to 2%, most of whom were children in the last case.

Conclusions—

The existing evidence suggests risk stratification with an electrophysiological study of patients with asymptomatic pre-excitation may be beneficial, along with consideration of accessory-pathway ablation in those deemed to be at high risk of future arrhythmias. Given the limitations of the existing data, well-designed and well-conducted studies are needed.

Myth: Intravenous amiodarone is safe in patients with atrial fibrillation and Wolff–Parkinson–White syndrome in the emergency department

Wolff–Parkinson–White (WPW) syndrome with atrial fibrillation (AF) is a potentially life-threatening problem requiring rapid conversion to sinus rhythm. The most recent American Heart Association guidelines for the treatment of patients with WPW, published in conjunction with the 2000 Advanced Cardiac Life Support (ACLS) guidelines, suggests that intravenous amiodarone is a first-line therapy for AF–WPW; however the evidence suggests this is a potentially dangerous myth.

Insights into cardiac conduction system formation provided by HCN4 expression

Specialized myocytes of the cardiac conduction system (CCS) are essential to coordinate sequential contraction of cardiac atria and ventricles. Anomalies of the CCS can result in lethal cardiac arrhythmias, including sick sinus syndrome and atrial or ventricular fibrillation. To develop future therapies and regenerative medicine aimed at cardiac arrhythmias, it is important to understand formation and function of distinct components of the CCS. Essential to this understanding is the development of CCS-specific markers. In this review, we briefly summarize available mouse models of CCS markers and focus on those involving the hyperpolarization cation-selective nucleotide-gated cation channel, HCN4, which selectively marks all components of the specialized CCS in adult heart. Recent studies have revealed, however, that HCN4 expression during development is highly dynamic in cardiac precursors. These studies have offered insights into the contributions of the first and second heart field to myocyte and conduction system lineages and suggested the timing of allocation of specific conduction system precursors during development. Altogether, they have highlighted the utility of HCN4 as a cell surface marker for distinct components of the CCS at distinct stages of development, which can be utilized to facilitate purification and characterization of CCS precursors in mouse and human model systems and pave the way for regenerative therapies.

A serious cause of panic attack

We report on a case of a patient with atrial fibrillation in the setting of Wolff-Parkinson-White syndrome. The patient underwent synchronized electrical cardioversion, typically considered safe and effective, which resulted in a dangerous complication for the patient (degeneration into ventricular fibrillation). Discussion of common rhythm disturbances in WPW and management strategies are reviewed.

Coronary sinus diverticulum as a cause of resistant posteroseptal pathway ablation

Coronary sinus (CS) anomalies such as diverticulum, persistent left superior vena cava or CS ostium dilatation are predominantly found in patients with accessory pathway-related tachycardias. Diverticulum of the proximal CS found in 7-11% of patients with postero-septal or left posterior manifests accessory pathways. We reported a 28 year old gentleman with manifested postero-septal accessory pathway, who underwent repeat electrophysiological study (EPS) and radiofrequency ablation for previously failed ablation. Huge CS diverticulum was identified by angiography as a reason for resistant accessory pathway. Successful RF ablation was achieved at the neck of the diverticulum without complications. Other associated anomalies were ruled out by cardiac computerized tomography (CT) and trans-esophageal echocardiography.

Safety and efficacy of flecainide in the treatment of symptomatic children with Wolff-Parkinson-White syndrome

Sudden cardiac death may occur in children with symptomatic and asymptomatic Wolff-Parkinson-White syndrome (WPWS). Symptomatic patients are usually treated with antiarrhythmic drugs until ablation of an accessory pathway (AP) could be performed. The objective of this study was to review the safety and efficacy of flecainide in the treatment of children with symptomatic WPWS. Twenty-two children (14 male) with WPWS and without structural heart disease were studied. AP location was achieved by electrophysiological testing or 12-lead electrocardiogram tracing. Symptomatic children (i.e., those frequent palpitations or supraventricular tachycardia episodes) received flecainide. Patients were followed-up for an average of 3.4 years until ablation of AP. Eighteen children reported clinical symptoms when first diagnosed, but only 13 initiated treatment during 16.23 months (range 1-55). Flecainide was effective in all patients: Seven became asymptomatic, and six experimented isolated episodes of palpitations. One child experienced hair loss as a side effect. AP location was as follows: left free wall (n = 7), right free wall (n = 4), posteroseptal (n = 8), and anteroseptal (n = 4). Ablation was performed without complications in 13 children. Symptomatic WPWS in children can be treated safely and efficiently with flecainide. It represents a good alternative therapy until AP ablation can be performed.

Cardiovascular safety of stimulant medications for pediatric attention-deficit hyperactivity disorder

Attention-deficit hyperactivity disorder (ADHD) is a common neurobehavioral disorder that is often treated with stimulants such as methylphenidate and mixed amphetamine salts. Despite their efficacy and long history of use, there is concern about their potential for adverse cardiovascular effects in children and adolescents. Data from placebo-controlled and open-label extension trials published after 2000 were reviewed, and cardiovascular adverse event data were compared. Both placebo-controlled and open-label extension trials have repeatedly shown stimulant-induced increases in mean blood pressure, heart rate, and QT interval in children, adolescents, and adults. Although these increases seem relatively minor, their existence raises questions regarding whether stimulants could influence the likelihood of sudden death or other serious cardiovascular consequences, especially in patients with underlying heart problems. Moreover, questions have been raised regarding the necessity of screening patients for occult or unrecognized heart problems that are felt to be adversely affected by stimulant use. Obtaining a baseline electrocardiogram for any patient starting stimulant treatment is reasonable if access to such screening is readily available and not too costly.

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.

[Recurrence of atrial fibrillation after successful radiofrequency catheter ablation of accessory pathway in patients with Wolff-Parkinson-White syndrome]

INTRODUCTION

Paroxysmal atrial fibrillation (AF) occurs in 11.5-39% of the patients with Wolff-Parkinson-White (WPW) syndrome and frequently, but not always, disappears after successful accessory pathway (AP) ablation.

OBJECTIVE

To determine AF recurrence rate, time to AF recurrence and predictors of AF recurrence after radiofrequency (RF) catheter-ablation of AP in WPW-patients with AF.

METHODS

Data from 245 consecutive patients with WPW-syndrome who underwent RF catheter-ablation of AP were analysed. A total of 52 patients (43 men, mean age: 42.5 +/- 14.1 years) with preablation history of spontaneous AF were followed up after definitive AP ablation. At baseline, structural heart disease and comorbidities were diagnosed in 19.2% and 21.2% of the patients, respectively.

RESULTS

During the follow-up of 5.2-3.7 years, 3 patients (5.7%) died; one of these patients, previously known for recurrent AF, died from ischaemic stroke. Symptomatic recurrence of AF was detected in 9 of 52 patients (17.3%). In 66.7% of these patients, AF recurrence was identified in the first year following the procedure. Kaplan-Meier analysis demonstrated that freedom from recurrent AF after 3 months was 94.2%, after 1 year 87.5% and after 4 years 84.3%. Univariate analysis showed that older age (p = 0.023), presence of structural heart disease (p = 0.05) and dilated left atrium (p = 0.013) were significantly related to AF recurrence. However, using multivariate Cox regression, older age was the only independent predictor of AF recurrence (HR = 2.44 for every life decade; p = 0.006). Analysis of ROC curves showed that, after the age of 36, the risk of AF recurrence abruptly increased.

CONCLUSION

Symptomatic recurrence of AF was detected in 17% of WPW-patients after definite RF ablation of AP. The time-dependent occurrence of AF recurrences and age-dependent increase in the rate of AF recurrence were identified. Closer follow-up and/or extension of drug therapy in older patients, at least in the first year after the procedure, seem prudent.

A multicenter, long-term study on arrhythmias in children with Ebstein anomaly

To assess the prevalence, history, and treatment of arrhythmias, in particular preexcitation and Wolff-Parkinson-White (WPW) syndrome, in patients with Ebstein anomaly (EA) during childhood and adolescence, we performed a multicenter retrospective study of all consecutive live-born patients with EA, diagnosed, and followed by pediatric cardiologists between 1980 and 2005 in The Netherlands. During a follow-up after EA diagnosis of 13 years 3 months (range: 6 days to 28 years 2 months), 16 (17%) of the 93 pediatric EA patients exhibited rhythm disturbances. Nine patients showed arrhythmic events starting as of the neonatal period. Supraventricular tachycardia was noted in 11 patients. One patient died in the neonatal period due to intractable supraventricular tachycardia resulting in heart failure and one patient died at 5 weeks of age most probably due to an arrhythmic event. The 14 surviving patients all show preexcitation, albeit 4 of them intermittently, and all have a right-sided accessory pathway location. Nine patients underwent catheter ablation of an accessory pathway. Only four patients are currently on antiarrhythmic drugs. The 17% prevalence of rhythm disturbances in pediatric EA patients, most commonly supraventricular arrhythmias, is significantly lower than in adult EA patients. Life-threatening rhythm disturbances are not frequent early in life. Symptomatic patients are well treated with radiofrequency catheter ablation.

The role of the accessory pathway radiofrequency catheter ablation in the secondary prevention of the malignant tachyarrhythmias in patients with Wolff-Parkinson-White syndrome

Background/Aim. The occurrence of atrial fibrillation (AF) in the presence of an accessory pathway (AP) that conducts rapidly is potentially lethal because the rapid ventricular response may lead to ventricular fibrillation (VF). The aim of the study was to determine long-term efficacy of AP catheter-ablation using radiofrequency (RF) current in secondary prevention of VF in WPW patients. Methods. Study included a total of 192 symptomatic WPW patients who underwent RF catheter-ablation of AP in our institution from 1994 to 2007 and were available for clinical follow-up for more than 3 months after procedure. Results. Before ablation, VF was recorded in total of 27 patients (14.1%). In 14 of patients (51.9%) VF was the first clinical manifestation of WPW syndrome. A total of 35 VF episodes were identified in 27 patients. The occurrence of VF was preceded by physical activity or emotional stress in 17.1% of cases, by alcohol abuse in 2.9% and by inappropriate intravenous drug administration in 28.6%. In addition, no clear precipitating factor was identified in 40% of VF cases, while informations about activities preceding 11.4% of VF episodes were not available. The follow-up of 5.7 ? 3.3 years was obtained in all of 27 VF patients. Of the 20 patients who underwent successful AP ablation, all were alive, without syncope or ventricular tachyarrhythmias during long-term follow-up. In 4 of 7 unsuccessfully treated patients, recurrence of supraventricular tachycardia and/or preexcited atrial fibrillation were recorded; one of these patients suddenly died of VF, 6 years after procedure. Conclusion. In significant proportion of WPW patients, VF was the first clinical manifestation of WPW syndrome, often precipitated by physical activity, emotional stress or inappropriate drug administration. Successful elimination of AP by percutaneous RF catheter-ablation is highly effective in secondary prevention of life-threatening tachyarrhythmias in patients with ventricular preexcitation.

Cardiac conduction disturbance detected in a pediatric population

OBJECTIVE

To delineate the prevalence and clinical implications of cardiac conduction disturbance (CCD) in school-age children.

STUDY DESIGN

Between 1999 and 2001, a citywide survey of 432,166 elementary and high school students had been performed in Taipei by questionnaire, electrocardiography, phonocardiography, and physical examination. Patients with any abnormalities on this survey were referred for final diagnosis.

RESULTS

After excluding those with congenital heart disease (CHD), the prevalence of CCD was 0.75%, higher in males than in females (0.78% vs 0.71%). Incomplete right bundle branch block (IRBBB; 0.32%), complete right bundle branch block (CRBBB; 0.11%), ventricular premature contraction (0.11%), and Wolff-Parkinson-White syndrome (0.067 %) were the most common diagnoses. Second-degree atrioventricular block, IRBBB, CRBBB, and intraventricular conduction delay were more common in males; and atrial premature contraction was more common in females. The prevalence of CCD increased with age, from 0.48% in elementary school students to 0.97% in high school students. After detection of CCD, 39 patients with previously undiagnosed atrial septal defect (ASD) and 15 high-risk patients were found. The sensitivity of IRBBB in screening for ASD was 34.67%.

CONCLUSIONS

The prevalence of CCD in children without CHD was 0.75%. Detection of CCD helped identify patients with unrecognized ASD and high-risk cardiac patients.

Atrial fibrillation in the Wolff-Parkinson-White syndrome: ECG recognition and treatment in the ED

Estimated to occur in 0.1% to 0.3% of the population, Wolff-Parkinson-White syndrome (WPW) is a condition where atrial impulses bypass the atrioventricular node and activate the ventricular myocardium directly via an accessory pathway. Clinical clues to the diagnosis include a young patient with previous episodes of palpitations, rapid heart rate, or syncope. Although several different rhythm presentations are possible, atrial fibrillation is a not infrequent dysrhythmia seen in the WPW patient. Electrocardiographic features suggestive of WPW atrial fibrillation include irregularity of the rhythm; a very rapid ventricular response; presence of a delta wave; and a wide, bizarre QRS complex. Stable patients suspected of having this condition should not receive agents that predominantly block atrioventricular conduction, but they may be treated with procainamide or ibutilide. If instability is present, electrical cardioversion is required.

Familial Wolff-Parkinson-White Syndrome: A Disease of Glycogen Storage or Ion Channel Dysfunction?

Wolff-Parkinson-White (WPW) syndrome is the most common cause of ventricular pre-excitation, a condition where, due to defects in the conduction pathway, all or part of the ventricle is excited earlier than would normally be expected, often leading to ventricular fibrillation and sudden cardiac death. It was recently discovered that many of the underlying mutations responsible for the familial form of WPW syndrome are located in the gene encoding for the regulatory gamma(2)-subunit (PRKAG2) of the AMP-activated protein kinase. The cellular mechanisms for the observed arrhythmias are currently being studied and may involve glycogen storage with associated hypertrophy as well as alterations in the properties of cardiac ion channels such as voltage-gated sodium channel. It is the aim of this review to discuss our current knowledge of the cellular disturbances underlying the induction of arrhythmias in patients with PRKAG2 mutations.

Common issues in sports cardiology

Many cardiac conditions found in athletes are amenable to athletic participation if well-managed. As always, a respect for the causes of sudden cardiac death in athletes is paramount. Although rare, sudden cardiac death in athletes is frequently preventable by careful pre-participation screening. The authors hope that more athletes will undergo screening, and that basic investigations, including but not limited to electrocardiography, will become more widespread. A high degree of surveillance for cardiac pathology in athletes is the duty of any sports medicine practitioner.

Cardiovascular Emergencies in the Pediatric Patient

Children who have heart disease may present to the emergency department (ED) in many stages of life with a range of cardiovascular manifestions, from minimally irritating palpitations to the life-threatening derangements of shock or lethal dysrhythmia. They can present with congenital heart disease, after a temporizing procedure has been performed or after their definitive repair. Children can also present with fever, weakness, dyspnea, syncope, or chest pain; alternatively, children may present to the ED with active dysrhythmia, pulmonary edema, or cardiogenic shock . These symptoms and presentations may result from Kawasaki disease,hypertrophic cardiomyopathy, or arrhythmia; therefore, emergency physicians must also be comfortable with the most common types of heart disease associated with these symptoms and presentations. The purpose of this article is to describe the physiology and presentation of undiagnosed congenital heart disease, to describe the complications that can occur after a staged or definitive repair,and to discuss acquired heart disease in children.

Cost-effectiveness of Project ADAM: a project to prevent sudden cardiac death in high school students

Public access defibrillation (PAD) in the adult population is thought to be both efficacious and cost-effective. Similar programs aimed at children and adolescents have not been evaluated for their cost-effectiveness. This study evaluates the potential cost-effectiveness of implementing Project ADAM, a program targeting children and adolescents in high schools in the Milwaukee Public School System. Project ADAM provides education about cardiopulmonary resuscitation (CPR) and the warning signs of sudden cardiac death (SCD) and training in the use and placement of automated external defibrillators (AEDs) in high schools. We developed decision analysis models to evaluate the cost-effectiveness of the decision to implement Project ADAM in public high schools in Milwaukee. We examined clinical model and public policy applications. Data on costs included estimates of hospital-based charges derived from a pediatric medical center where a series of patients were treated for SCD, educational programming, and the direct costs of one AED and training for 15 personnel per school. We performed sensitivity analyses to assess the variation in outputs with respect to changes to input data. The main outcome measures were Life years saved and incremental cost-effectiveness ratios. At an arbitrary societal willingness to pay $100,000 per life year saved, the policy to implement Project ADAM in schools is a cost-effective strategy at a threshold of approximately 5 patients over 5 years for the clinical model and approximately 8 patients over 5 years for the public policy model. Implementation of Project ADAM in high schools in the United States is potentially associated with an incremental cost-effectiveness ratio that is favorable.

Molecular genetic basis of sudden cardiac death

This article outlines the up-to-date understanding of the molecular basis of disorders that cause sudden death. Several arrhythmic disorders that cause sudden death have been well-described at the molecular level, including the long QT syndromes and Brugada syndrome; this article reviews the current scientific knowledge of these diseases. Hypertrophic cardiomyopathy, a myocardial disorder that causes sudden death also has been well-studied. Finally, a disorder in which myocardial abnormalities and rhythm abnormalities coexist, arrhythmogenic right ventricular dysplasia, is described.

Wolff-Parkinson-White Syndrome: Essentials for the Primary Care Nurse Practitioner

PURPOSE

To provide nurse practitioners with a basic understanding of the pathophysiology, clinical characteristics, diagnostic methods, and management of Wolff-Parkinson-White (WPW) syndrome.

DATA SOURCES

Selected research and clinical articles.

CONCLUSIONS

WPW syndrome is the most common form of ventricular preexcitation. The ventricular myocardium is activated earlier than expected by an accessory conduction pathway that allows a direct electrical connection between the atria and ventricles. Although many patients remain asymptomatic throughout their lives, approximately half of the patients with WPW syndrome experience symptoms secondary to tachyarrhythmias, such as paroxysmal supraventricular tachycardia, atrial fibrillation, atrial flutter, and, rarely, ventricular fibrillation and sudden death. Symptoms include palpitations, dizziness, syncope, and dyspnea. Diagnosis is usually made by electrocardiogram findings, but further testing may be warranted to confirm the diagnosis.

IMPLICATIONS FOR PRACTICE

A thorough patient history and physical examination can aid the practitioner in identifying patients who may have WPW syndrome. With appropriate referral, treatment, and patient education, patients with WPW syndrome can expect to have a normal life expectancy and good quality of life.