Wolff-Parkinson-White Research Articles

АССОЦИАТИВНАЯ РОЛЬ ПОЛИМОРФИЗМА RS121908987 ГЕНА PRKAG2 В РАЗВИТИИ СИНДРОМА WPW

The study of cardiac arrhythmias and conduction is one of the most urgent and important tasks, since these diseases are often the cause of sudden cardiac death. We assumed that the study of the contribution of "predictor genes" of heart rhythm and conduction disorders would expand knowledge about the etiology and pathogenesis of these diseases. Thus, the purpose of our research was to study the contribution of the rs121908987 polymorphism of the PRKAG2 gene to the development of WPW syndrome. Material and methods: 200 patients with VPU syndrome were examined, among them men n=97 [18:32.66;81]; women n=103 [18;47,92;83]. All patients underwent clinical, laboratory, somatometric, instrumental studies, as well as molecular genetic studies DNA isolation was performed by the standard phenol-chloroform method. Genotyping of the PRKAG2 gene was performed by PCR-PDRF analysis (polymerase chain reaction-polymorphism of restriction fragment lengths). Statistical data processing was carried out using the Excel application software package, Statistica for Windows 10.0, IBM SPSS 20.Differences in the frequency distribution of alleles and genotypes of the PRKAG2 gene between the groups were assessed using the χ2 criterion. The relative risk of disease for a specific allele or genotype was calculated as the odds ratio (OR). Results: a statistically significant predominance of the heterozygous GA genotype in patients with VPU syndrome, compared with those in the control group (8 and 2%, respectively; Table 1). There was also a statistically significant predominance of allele A carriers in the group of patients with VPU syndrome by 4%, compared with those in the control group (2%). The risk of developing PRKAG2 genotype GA syndrome, estimated by OSH, was 2.09 times higher (95% CI 1.88–2.32; p <0.001 compared with genotypes GG and AA, and in carriers of the A allele – 2.04 times higher (95% CI 1.90–2.19; p <0.001) compared with allele A (see Table 2). Conclusions: The results of the study confirmed the contribution of polymorphism rs121908987 of the PRKAG2 gene to the development of VPU syndrome.

Recurrent Orthodromic SVT AVRT with Multiple Accessory Pathway in WPW Syndrome: Ablate All or Not?

Background: Patients diagnosed with Wolff-Parkinson-White syndrome (WPW) have a relatively low, nevertheless persistent risk of unexpected mortality. However, this risk can be effectively mitigated by applying radiofrequency catheter ablation targeting the accessory pathway. It is difficult to accurately study predictors because only a minority of patients develop potentially malignant arrhythmias (MA) or passed away, despite essential risk variables being relatively well-known.1 This study aimed to describe ablation in WPW syndrome. Case presentation: A 16-year-old male presents with symptoms characterized by palpitations during intense physical exertion, followed by chest pain episodes. The physical examination, CXR, laboratorium, and echocardiography were all within the normal range; his ECG showed shortened PR interval and a delta wave with a positive delta wave at V1 and mostly positive at the inferior lead. He also has recorded ECG when the patient has a tachycardia event with SVT AVRT orthodromic pattern. He underwent EP Study and had several accessory pathways at the posteroseptal mitral annulus and anteroseptal tricuspid. The decision was made to perform ablation on the posteroseptal accessory pathway located at the mitral annulus. An electrophysiology (EP) investigation was conducted at the anteroseptal tricuspid annulus, which did not induce tachyarrhythmia. Conclusion: Wolff-Parkinson-White syndrome is a congenital cardiac pathway formation, with not all accessory pathways causing tachyarrhythmias. Ablation therapy is necessary for patients with multiple pathways, with pathways with an ERP less than 250 being the only option. Keyword: Ablation, Multiple Accessories Pathway, SVT AVRT Orthodromic, WPW Syndrome.

Association of Atrial Fibrillation and/or Flutter With Adverse Cardiac Outcomes and Mortality in Patients With Wolff-Parkinson-White Syndrome.

Wolff-Parkinson-White (WPW) syndrome is characterized by the presence of accessory pathways and development of potentially malignant arrhythmias that can lead to sudden cardiac death. We aimed to determine the impact of atrial fibrillation and/or flutter (AF/AFL) on adverse cardiac outcomes and mortality in patients with WPW syndrome. This study identified a cohort of Military Health System patients with WPW syndrome from January 1, 2014, to December 31, 2019. The cohort was divided into 2 subgroups by the presence or absence of AF/AFL. Cardiac composite outcome and mortality were assessed. Kaplan-Meier curves were constructed to assess the bivariate association between exposure and these 2 study outcomes. Cox proportional models were used to estimate the hazard ratios and 95% CIs associated with the cardiac composite outcome and mortality. Of 35,539 patients included in the study, 19,961 were female (56.2%), the mean (SD) age was 62.9 (18.0) years, and 5291 patients (14.9%) had AF/AFL. The cardiac composite outcome and mortality incidence rates per 100 person-years in the AF/AFL vs non-AF/AFL subgroups were 8.18 vs 4.90, and 4.09 vs 2.13, respectively (P < .001). There were 3130 (8.8%) deaths. After adjusting for confounding variables, the AF/AFL subgroup maintained a 12% and 16% higher association with the composite outcome and mortality, respectively. Patients with WPW syndrome and AF/AFL have a higher association with adverse cardiac outcomes and death. Consideration for more aggressive electrophysiology screening and ablation strategies may be warranted in this population.

Pre-Excited Atrial Fibrillation in Wolff-Parkinson-White (WPW) Syndrome: A Case Report and a Review of the Literature.

Wolff-Parkinson-White (WPW) syndrome is defined by specific electrocardiogram (ECG) changes resulting in ventricular pre-excitation (the so-called WPW pattern), related to the presence of an accessory pathway (AP), combined with recurrent tachyarrhythmias. WPW syndrome is characterized by different supraventricular tachyarrhythmias (SVT), including atrioventricular re-entry tachycardia (AVRT) and atrial fibrillation (AF) with rapid ventricular response, with AVRT being the most common arrhythmia associated with WPW, and AF occurring in up to 50% of patients with WPW. Several mechanisms might be responsible for AF development in the WPW syndrome, and a proper electrocardiographic interpretation is of pivotal importance since misdiagnosing pre-excited AF could lead to the administration of incorrect treatment, potentially inducing ventricular fibrillation (VF). Great awareness of pre-excited AF's common ECG characteristics as well as associated causes and its treatment is needed to increase diagnostic performance and improve patients' outcomes. In the present review, starting from a paradigmatic case, we discuss the characteristics of pre-excited AF in the emergency department and its management, focusing on the most common ECG abnormalities, pharmacological and invasive treatment of this rhythm disorder.

Atrial Fibrillation in Wolff Parkinson White (WPW) Syndrome: Case Report and Review of the Literature

The occurrence of atrial fibrillation (AF) transmitted to the ventricles by an accessory pathway is a rare, potentially serious arrhythmia. The risk of ventricular fibrillation is a fatal complication that can be increased by certain medications such as digitalis. AF can be the initial presentation of WPW syndrome, in which case it is often poorly tolerated. We report the case of a 42-year-old patient with no particular history, who consulted for palpitations that appeared at rest, a few hours previously; systolic blood pressure was 80 mm Hg without signs of shock. The ECG showed rapid AF with wide QRS. After reduction by external electric shock, the post-ictal ECG was in favor of WPW syndrome. The initial assessment was quickly carried out, and the patient was treated with a combination of two antiarrhythmic drugs. The occurrence of rhythm disturbances requires an etiological assessment on which the specific treatment will depend. In WPW syndrome, stratification of the individual risk of sudden death is essential in the therapeutic management of patients.

Differentiating between Exercise-Induced ST-Segment Abnormalities Secondary to Wolff-Parkinson-White (WPW) Syndrome and Acute Myocardial Infarction

Differentiating between Exercise-Induced ST-Segment Abnormalities Secondary to Wolff-Parkinson-White (WPW) Syndrome and Acute Myocardial Infarction

Atypical Pre-excitation Pattern in Asymptomatic Wolff-Parkinson-White—A Hallmark for High Risk?

Abstract Introduction Delta wave morphology during sinus rhythm on 12 lead ECG usually allows for a relatively precise prediction of the anatomic location of an accessory pathway (AP) provided that the rhythm is fully pre-excited. However, the pre-excitation pattern during sinus rhythm usually offers little information about sudden cardiac death (SCD) risk in adult patients with asymptomatic Wolf-Parkinson-White (WPW). Case Presentation A 42-year-old policeman was referred for an asymptomatic WPW pattern with an unusual delta wave. Initial mapping showed that atrio-ventricular (A-V) fusion on the lateral mitral annulus and radiofrequency (RF) ablation induced a shift in the pre-excitation pattern. Re-mapping identified A-V fusion on the left postero-septal area. Another RF application eliminated pre-excitation. Re-mapping identified A-V fusion on the postero-septal aspect of the mitral annulus and another RF application almost instantaneously induced an A-V split and loss of pre-excitation. Post-ablation testing proved normal anterograde A-V conduction without pre-excitation and no ventriculo-atrial conduction. Serial ECGs proved the persistent loss of pre-excitation at one-month of follow-up. Conclusion This case highlights the diagnostic challenges associated with atypical pre-excitation patterns and the importance of a thorough evaluation in asymptomatic individuals. Patients with atypical pre-excitation may harbor multiple accessory pathways (MAPs) and should be carefully assessed to mitigate the risk of SCD.

Do children with asymptomatic ventricular preexcitation have similar quality of life as healthy children?

To our knowledge, no studies have assessed quality of life (QoL) in asymptomatic children with a preexcitation electrocardiogram pattern. To evaluate the QoL of children with asymptomatic Wolff-Parkinson-White (WPW) syndrome. This study involved QoL assessment of 31 children with asymptomatic preexcitation and 82 healthy children using the WHOQOL-BREF and the Pediatric Arrhythmia Related Score (PARS), a specific questionnaire that we have developed, which is related to patients' feelings and observations concerning arrhythmia. There were no significant differences between the two groups in all the measured domains; however, there were significant differences regarding general satisfaction with their health condition (P = 0.01). There were no differences in general satisfaction with the QoL, but WPW children more often experienced palpitations than the control group (P <0.001) and were more likely to feel sad (P = 0.046) and nervous (P = 0.04) compared to healthy children. The children with WPW were more dissatisfied with their health compared to healthy children. Although both groups of children had similar levels of satisfaction with their QoL, some areas of physical and psychological parameters of QoL were worse in WPW children. The PARS questionnaire is a useful tool as a disease-specific QoL instrument, which supplements the general questionnaire and aids in clinical practice and decision-making.

Short history of the DC-Catheter-Ablation

Direct current (DC) catheter ablation in 5patients aiming to interrupt rapid atrioventricular (AV) conduction with atrial fibrillation and subsequent pacemaker implantation was first published by M.M.Scheinman etal. (San Francisco, CA, USA) in 1982. In Germany, L.Seipel, G.Breithardt, and M.Borggrefe reported their first experience with DC catheter ablation in 1984, followed by the group in Bonn (M.Manz and B.Lüderitz) in 1985. The first international DC catheter ablation registry, which also included four German centers, reported DC catheter ablation results of 127 patients in 24centers in 1984. Complete AV block was achieved in 71% patients. In 1992, the Hannover group (H‑J.Trappe, H.Klein and J.Huang) reported results of DC catheter ablation of AV conduction performed between 1983 and 1990 in 100 patients (86% with rapid atrial fibrillation, 14% with AV-node reentry tachycardias). The first successful DC catheter ablation in apatient with Wolff-Parkinson-White (WPW) syndrome was reported in 1985 by F.Morady etal. (San Francisco, CA, USA). In 1987, M.Borggrefe etal. were the first to report aswitch from DC catheter ablation to ahigh-frequency (HF) catheter ablation procedure in apatient with WPW syndrome. The use of DC catheter ablation to treat ventricular tachycardia (VT) was described by G.O.Hartzler (Kansas City, MO, USA) in 3patients in 1983. M.Borggrefe etal. (1989) reported on 24patients who underwent DC catheter ablation for VT. Of those, 17patients did not have VT recurrence within the following 14months. In 1994, the Hannover group (H-JTrappe, H.Klein) published their 5‑year long-term results of DC catheter ablation of VT in 51patients. VT recurrence occurred in 57% patients and overall mortality was also high (16%). Acomparison of DC catheter ablation with HF catheter ablation for recurrent VT was reported in 1994 by G.Gonska etal. (Göttingen, Germany). After 2years follow-up, success rates were not found to be significantly different.

History of surgical treatment of cardiac arrhythmias in Germany : Surgical treatment of ventricular tachycardia and supraventricular tachycardia, especially pre-excitation syndromes (WPW)

The history of surgical treatment of ventricular tachycardias (VT) is short, lasting from 1978 until 1993. "Indirect procedures" with infarct scar resection were performed without electrophysiologic studies, whereas "direct procedures" consisted of either complete endocardial incisions ("encircling endocardial ventriculotomy") or large endocardial resections ("endocardial peel-off" technique) after precise epicardial and endocardial mapping procedures. In Germany, the first to report on intra-operative electrophysiologic mapping for VT treatment were Ostermeyer, Breithardt and Seipel in 1979. In 1981, the Hannover group (Frank, Klein) published their first results of surgical treatment of VT. In 1984, Ostermeyer et al. demonstrated that apartial endocardial incision resulted in more beneficial results with less myocardial damage (8% versus 46%) than applying acomplete encircling incision. In 1987, the Düsseldorf group reported treatment results of 93patients. After 5years, 77% had no VT recurrence, while total mortality after 1year was 11% and after 5years 30%. In 1992, the Hannover group reported results of 147patients after endocardial resection for VT. Total mortality after 3years was 27%; recurrence of VT events occurred in 18% of the surviving cohort.The history of surgical procedures for supraventricular tachycardia (SVT), in particular Wolff-Parkinson-White (WPW) syndrome, is even shorter than that of surgery for VT. As early as 1969, Sealy, Gallagher and Cox reported the first cases of surgical intervention for WPW syndrome via endocardial access in cardioplegic arrest. In 1984, Guiraudon and Klein reported on anew procedure with epicardial access to the accessory bundle without cardioplegia in laterally localised conduction pathways. In Germany, too, the groups in Düsseldorf (Ostermeyer, Seipel, Breithardt, Borggrefe) from 1980 and the Hannover group (Frank, Klein and Kallfelz) from 1981 performed surgical procedures for WPW syndrome. In 1987, Borggrefe reported on 18patients with WPW syndrome and atrial fibrillation who had undergone surgery. After 2years, 14 of 18patients had no recurrences of tachycardia; in 1989, Frank, Klein and Kallfelz (Hannover) reported on 10children (2-14 years) operated on using the cryoablation technique. Between 1984 and 1992, atotal of 120 patients with SVT, mostly WPW syndrome, were operated on in Hannover; after 42months, 12patients had a recurrence of SVT. Two patients died during the reoperation.

Smartphone ECG Based Successful Diagnosis of WPW Syndrome Under Both Resting and Stress Test Conditions: A Case Report

Background: Wolff-Parkinson-White (WPW) syndrome arises from the presence of an accessory pathway in the heart, disrupting normal electrical conduction between the atria and ventricles. Diagnosis via electrocardiography typically reveals characteristic features such as Delta waves, shortened PR intervals, and RR variabilities. Case Summary: The authors present the case of a 23-year-old male with a history of tobacco and alcohol use, exhibiting electrocardiographic manifestations consistent with WPW syndrome. Employing a Smartphone-based 12-lead ECG and bicycle ergometer, additional testing under resting and stressed conditions revealed a spectrum of abnormalities including T-wave inversions, tachyarrhythmias, conduction blocks, ST depressions, shortened PR intervals, and persistent Delta waves. Despite the absence of symptoms, a stress test achieving 10 METS over 5 minutes demonstrated the potential for ventricular tachycardia. Discussion: Following evaluation by a cardiologist, a watchful waiting approach was recommended, with no pharmacological intervention prescribed. This report underscores the utility of smartphone ECG technology in managing WPW syndrome, offering insights into dynamic cardiac responses during stress and informing clinical decision-making. Regular follow-up ECG assessments at six-month intervals were advised to monitor for emerging symptoms. The importance of prompt consultation with a cardiologist upon symptom onset cannot be overstated, given the inherent risk of life-threatening arrhythmias associated with WPW syndrome.

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.

A Case Report on Wolff–Parkinson–White syndrome in Pregnancy

Abstract Wolff–Parkinson–White syndrome (WPWS) is a rare congenital pre-excitation syndrome characterised by the presence of an accessory pathway that predisposes to tachyarrhythmia and sudden death. A 26-year-old G4P1L1A2 woman was admitted at 11 weeks of gestation with complaints of headache, vomiting, chest pain and palpitation. ECG elicited supraventricular tachycardia, short PR interval and wide QRS complex. With a reactive non-stress test, the patient was continuously monitored and treated with beta-blockers. Both pregnancy and the WPWS aggravate each other’s tendency to produce arrhythmias. Adequate preparation with fluid preloading and positioning, securing appropriate drugs and emergency equipment, avoidance of tachyarrhythmia and prompt treatment on occurrence is required for the safety of both the mother and the foetus. Prompt diagnosis and rigorous and collaborative team management are very essential to save the patient’s life.

Pharmacotherapy of Wolff-Parkinson-White (WPW): A Review for Nurse Practitioners

Wolff-Parkinson-White (WPW) is a congenital condition where patients have ≥1 accessory pathways with the ability to bypass the atrioventricular node and cause ventricular preexcitation. These patients are at increased risk of arrhythmia and sudden cardiac death. Atrial fibrillation is a potentially fatal form of arrhythmia. In patients with WPW, atrial fibrillation can degenerate to ventricular fibrillation. This report provides acute care nurse practitioners with an updated outline of the diagnostic criteria for WPW and sheds some light on its pharmacotherapy.

Outcomes of 10 years of cardiac screening of elite New Zealand athletes

Abstract Background/Introduction Cardiac screening of competitive athletes for conditions associated with sudden cardiac death is recommended by bodies including the European Society of Cardiology. High Performance Sport New Zealand (HPSNZ) commenced cardiac screening of elite Olympic sport athletes in 2012. Purpose To report the 10 year outcomes and findings of the HPSNZ cardiac screening program, including comparisons of electrocardiogram (ECG) features between sexes, sports and ethnicities. Methods Athletes were screened by HPSNZ from February 2012-June 2022 in accordance with HPSNZ protocols and as required by their International Federations. Screening included a personal/family history, physical examination and resting 12-lead ECG (interpreted by a cardiologist experienced in athlete ECGs), and athletes were followed for up to 11 years. Clinical findings and ECGs were managed contemporaneously as required. In July 2022 all screening records, including demographic data, ECGs, follow-up testing and diagnoses were reviewed. Although ECG guidelines changed during the period, any abnormal/equivocal ECGs were re-reviewed using the International Criteria. Comparisons between groups were performed using Fisher’s exact test (2-sided, p&amp;lt;0.05 considered significant). Results 2075 ECGs from 1189 athletes (53% female, mean age 21 years; 83% European, 14% Māori and Pacific Islander, 3% other ethnicities) were included. Major diagnoses included Wolff-Parkinson-White (WPW) syndrome (0.7%) and cardiomyopathies (0.3%). Overall, 3.5% of ECGs were abnormal (International Criteria). ECGs of female athletes were more frequently abnormal (4.4% vs 2.5%, p=0.02) and had more abnormal T-wave inversion (TWI) (3.1% vs 0.9%, p=0.0005) compared to males. 47% of the abnormal TWI in females was limited to V1-V3 with no other ECG abnormalities. There were no differences in the proportion of abnormal ECGs between the highest intensity/endurance sports and other sports, nor between Māori and Pacific Island athlete ECGs compared with European (Table 1). No athletes retired for cardiac reasons, there were no cardiac deaths nor major cardiac incidents during the period (mean follow up from first screening: 73 months). There was a significant reduction in follow-up tests recommended after the introduction of the International Criteria. Conclusions WPW was the most frequent diagnosis, with very little cardiomyopathy found in this cohort. The proportion of abnormal ECGs was low overall, and lowest after the introduction of the most recent athlete ECG guidelines, likely reflecting enhanced specificity. ECGs of female athletes were more frequently abnormal, predominantly because of anterior TWI V1-V3, which potentially could be considered a normal finding in elite female athletes. We report for the first time a comparison between Māori/Pacific Island athletes and European athletes, showing no difference in the proportion of abnormal ECGs, although further data are needed.

Syncopes in adolescents in sport

The study analyzes current data on syncope in children and adolescents. The study presents the classification of syncope and briefly describes the clinical manifestations of neurally mediated syncope and the main methods of its diagnosis and treatment. Syncopes associated with organic cardiac pathologies and primary cardiac arrhythmias are caused by hypertrophic cardiomyopathy, arrhythmogenic cardiomyopathy, coronary artery anomalies, primary long QT syndrome, WolffParkinsonWhite syndrome, and bradyarrhythmias. The diagnostic features of syncope in children and young athletes and modern approaches to treatment and prevention are discussed.&#x0D; Although most syncopes in athletes are not associated with physical activity and have a neurotransmitter genesis, a thorough medical examination is needed. Factors that induce the development of syncopes in athletes must be identified. A prerequisite for admission to sports is the exclusion of the cardiac and arrhythmogenic reasons of syncopes. The decision to expand the sports regime should be made only after a thorough collection of medical history, including family history, and a comprehensive examination. In addition, the degree of risk in view of injuries, provocation, or fatal events following the loss of consciousness during sports must be estimated. This is extremely relevant for sports such as swimming, complex coordination sports (gymnastics and acrobatics), auto and motor sports, and alpine skiing.&#x0D; Although syncopes are common problems in pediatric practice, with only a few cases with cardiac causes based on structural or primary electrical myocardial diseases, they pose the greatest danger in sports medicine. Thus, such conditions must be excluded in young athletes because sports load can aggravate cardiac pathologies, which cause syncopes, due to untimely diagnosis before the start of a sports career.

Abstract 12838: Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-Like Episodes (MELAS) and m.3243A&gt;G Mutations Have Higher Prevalence of Wolff-Parkinson-White Syndrome

Background: Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) is one of the most common mitochondrial disorders. Cardiovascular involvement has been reported in up to 30% of MELAS patients with varying clinical presentations from non-specific cardiogenic abnormalities to conduction abnormalities, cardiomyopathies, heart failure, fatal arrhythmias and cardiac death. Although conduction defects are a known complication, the frequency of Wolff-Parkinson-White (WPW) Syndrome among MELAS patients and mutations associated with MELAS is uncertain, and their association with cardiomyopathy and treatment outcomes have rarely been reported. Methods: A retrospective chart review of 50 MELAS patients from January 2007 to December 2022 from the Neuroscience Institute at University of Texas Houston was conducted. Medical histories, genetic testing, electrocardiograms, echocardiograms, and electrophysiology studies were reviewed. Results: 43 patients were included (mean age 23.8, median age 18.5, range 2-58). Eight of 43 patients with MELAS (20 %), inclusive of one of 3 patients with m.4317A&gt;G (33.3%) and seven of 40 patients with m.3243A&gt;G variants had electrocardiographic findings consistent with WPW. Other conduction abnormalities were noted in ten of 20 patients (50%) with m.3243A&gt;G with neurological involvement and six of 20 patients (30%) with m.3243A&gt;G mutation without strokes. Four patients required electrophysiology studies with ablation (mean age 8.5, range 7-10), one for inappropriate sinus tachycardia resistant to several medications, and three patients with WPW syndrome all of whom required repeat ablations. Conduction abnormalities had a positive correlation with higher heteroplasmy levels (mean 35 % vs 51%, 95% CI -30.2 to -2.88, p=0.019). Six patients with MELAS had cardiomyopathy of varying severity which were all associated with conduction abnormalities, including two patients with WPW syndrome (p=0.014). Conclusion: The prevalence of WPW in patients with MELAS syndrome and the m.3243A&gt;G variant appears much higher than in the normal population and may require multiple electrophysiology studies ablations to treat. Routine cardiology screening is recommended for early detection.

Abstract 15650: Recovery of Cardiomyopathy Following Accessory Pathway Ablation

Background: Wolf-Parkinson-White (WPW) can cause significant arrhythmia in addition to left ventricular (LV) dessynchrony and cardiomyopathy, which may be reversible by accessory pathway ablation. Case: A 21-year-old female athletics major college student presents with dyspnea, fatigue and occasional palpitations associated with dizziness. Electrocardiogram (EKG) revealed WPW with left bundle branch block pattern suggestive of right-sided bypass tract (panel A). Transthoracic echocardiogram (TTE) revealed LV ejection fraction (LVEF) 35 - 40% and significant interventricular dessynchrony on M-mode (panel B). Decision-making: It was felt that her symptoms and LV dysfunction are due to QRS widening and possibly arrhythmia caused by the bypass tract, and that ablation is warranted. Electrophysiology study 3-D map revealed 2 insertion points of the bypass tract along the tricuspid annulus (panel C). Ablation was performed initially along the inferior tricuspid annulus, leading to QRS complex narrowing with a change in the delta wave axis. Another activation site was mapped separately to the anterolateral tricuspid annulus; ablation at this site eliminated pre-excitation altogether. Post procedure EKG revealed normalization of the PR interval and diffuse T wave abnormalities likely due to cardiac memory (panel D). Follow-up in 6 weeks revealed an LVEF of 60 - 65% and normal wall motion on TTE with improvement of her symptoms; she was cleared to resume sports. Conclusion: WPW can be associated with significant cardiomyopathy and heart failure due both to arrhythmia and marked LV dessynchrony, which may be reversed by radiofrequency ablation.

Abstract 14411: Block in the Fasciculoventricular Pathway in a Complex Arrhythmia Presentation

Background: Fasciculoventricular pathway (FVP) is a rare form of preexcitation without known clinical tachycardia. As it is connected to the His bundle, they conduct whenever it is engaged. Conduction through the His Bundle but block at FVP has not been reported. Case presentation: We present a case of a 42-year-old male with a history of Wolff-Parkinson-White syndrome (WPWS), supraventricular tachycardia (SVT), syncope, embolic stroke, paroxysmal atrial fibrillation, hypertension, hypothyroidism, Sjogren's syndrome and prior unsuccessful attempts at elimination of the preexcitation. He underwent electrophysiology (EP) study for presumed SVT ablation. The EP study identified an FVP as the cause of preexcitation, and the planned accessory pathway ablation was deemed unnecessary. Atrial tachycardia originating from the right superior pulmonary vein (PV) was induced, eventually degenerating into atrial fibrillation, and the patient successfully underwent pulmonary vein isolation with the resolution of symptoms. Discussion: FVP is usually an incidental finding when patients with symptomatic preexcitation are studied. If tachycardia is induced, it is unrelated to the preexcitation. The FVP is connected to the His bundle and invariably conducts if the impulse engages the His Bundle. We are unaware of a case when the His bundle conducts, but the impulse loses preexcitation due to a block in the FVP. This unusual finding was noted in our case. To further confirm the location of the accessory pathway, IV adenosine was given with a complete heart block suggesting the preexcitation is beyond the level of the AV node and within the conduction system. It is not at the annulus with independent atrial and ventricular insertion, typical of an accessory pathway. Conclusions: This case demonstrates an FV pathway's unusual conduction block and physiological characteristics.

Abstract 17557: Single Limb-Lead Electrocardiogram Accuracy in Screening for Ventricular Pre-Excitation

Introduction: Consumer devices capable of recording bipolar ECGs have been investigated and validated for atrial fibrillation detection and QT interval monitoring. Application of the technology to other electrical abnormalities like Wolff-Parkinson-White (WPW) is limited but could enhance the ability to screen for risk of cardiac arrhythmias before they occur. Aims: 1. Determine how frontal lead ECGs perform in identification of ventricular pre-excitation (VPE).2. Determine which of the standard 3 bipolar leads perform best for this detection.3. Quantify the impact of training of the interpreter on identification of VPE with single lead tracings. Methods: Standard 12-lead ECGs were obtained from 20 patients before and after successful radiofrequency ablation of a single manifest accessory pathway. 3-second tracings were abstracted from leads I, II, and III from each ECG and were presented in random order to interpreters of varying experience and specialization who were asked to evaluate whether the tracing showed VPE. Results were tabulated to determine the accuracy of VPE identification. Descriptive statistics of the performance of each lead (alone and in combinations) and interpreter type were calculated. Results: A total of 52 respondents interpreted 5108 ECG tracings. Some respondents did not read all tracings and there were unequal numbers of respondents in the different interpreter categories. The Table below depicts the performance of each lead and respondent subgroups. Conclusions: VPE can be identified with reasonable accuracy using a single limb-lead ECG tracing, with lead I performing better than leads II and III. Addition of lead II or III improved accuracy by 5% only. Most consumer devices record lead I, suggesting that they could be used to screen for WPW. Interpreter specialization correlated more with accuracy than training status.