Preexcitation Research Articles

Perioperative Management in a Patient with WPW Syndrome undergoing Plastic Surgery.

Perioperative management of patients with preexcitation may become quite challenging, especially if there is no time for adequate preoperative investigation and clinical optimisation, as in emergencies, or even worse, in undiagnosed cases. It is possible that the poorly controlled or unknown underlying electrophysiological abnormality will become unmasked during anaesthesia and surgery, giving rise to potentially life-threatening arrhythmias.
 In the literature, pre-excitation syndromes have been mainly approached from the view of the disease (i.e., presentation, diagnosis, treatment), while anaesthetic data are scarce.
 This case report aims to focus on the perioperative management of patients with WPW.
 Conclusion; Managing such cases provides an opportunity to revisit important considerations on Wolff-Parkinson-White syndrome Avoiding neuromuscular blockers may make a difference in avoiding arrhythmias when laryngeal mask airway / general anaesthesia is required in patients with Wolff-Parkinson-White syndrome. Sympathetic stimulation should be avoided as it may shorten the refractory period of AP and alleviate life-threatening arrhythmias.

Shortened PQ interval in the differential diagnosis of Anderson-Fabry disease: a case report

In this article, we present a case of a patient with a late diagnosis of Fabry disease caused by a pathogenic variant in the GLA gene (p.1287_1288dup), who repeatedly attempted interventional treatment of Wolff-Parkinson-White Syndrome due to characteristic electrocardiographic pattern of ventricular preexcitation and paroxysmal arrhythmias. The proposed pathognomonic signs of the disease will ensure timely diagnosis and the appointment of specific treatment.

Analysis of the influencing factors associated with dyssynchrony and cardiac dysfunction in children with ventricular pre-excitation.

To investigate the correlation between ventricular pre-excitation-related dyssynchrony, on cardiac dysfunction, and recovery. This study included 76 children (39 boys and 37 girls) with a median age of 5.25 (2.67-10.75) years. The patients with pre-excitation-related cardiac dysfunction (cardiac dysfunction group, n = 34) had a longer standard deviation of the time-to-peak systolic strain of the left ventricle and larger difference between the maximum and minimum times-to-peak systolic strain than those with a normal cardiac function (normal function group, n = 42) (51.77 ± 24.70 ms versus 33.29 ± 9.48 ms, p < 0.05; 185.82 ± 92.51 ms versus 111.93 ± 34.27 ms, p < 0.05, respectively). The cardiac dysfunction group had a maximum time-to-peak systolic strain at the basal segments of the anterior and posterior septa and the normal function group at the basal segments of anterolateral and posterolateral walls. The prevalence of ventricular septal dyssynchrony in the cardiac dysfunction group was significantly higher than that in the normal function group (94.1% (32/34) versus 7.7% (3/42), p < 0.05). The patients with ventricular septal dyssynchrony (n = 35) had a significantly higher prevalence of intra-left ventricular systolic dyssynchrony than those with ventricular septal synchrony (n = 41) (57.1% (20/35) versus 14.6% (6/41), p < 0.05). During follow-up after pathway ablation, the patients who recovered from intra-left ventricular dyssynchrony (n = 29) had a shorter left ventricular ejection fraction recovery time than those who did not (n = 5) (χ2 = 5.94, p < 0.05). Among the patients who recovered, 93.1% (27/29) had a normalised standard deviation of the time-to-peak systolic strain and difference between the maximum and minimum times-to-peak systolic strain within 1 month after ablation. Ventricular pre-excitation may cause ventricular septal dyssynchrony; thus, attention must be paid to intra-left ventricular dyssynchrony and cardiac dysfunction. Whether intra-left ventricular systolic dyssynchrony can resolve within 1 month may be a new early predictor of patient prognosis.

Glycogen storage disease: PRKAG2 syndrome

PRKAG2 syndrome is a rare genetic disease that isinherited in an autosomal dominant fashion and is caused by mutationsin the PRKAG2 gene. Clinical symptoms include early onset, ventricular preexcitation, cardiac hypertrophy, and progressive atrioventricular block. The PRKAG2 syndrome is characterized by genetic heterogeneity, which makes early detection difficult; genophenotypic correlations have been documented. In this article, we provide an overview of the literature data and experience from the cardiology department of the National Medical Research Center for Children’s Health of the Russian Ministry of Health in the diagnosis and management of patients with PRKAG2 syndrome, and present the clinical and genetic characteristics of the p.R302Q and p.H383R variants of the PRKAG2 gene.

The Risk of Sudden Death Associated with Symptomatic and Asymptomatic Ventricular Pre-excitation in Athletes

Abstract Sudden death (SD) in athletes is a potential avoidable dramatic scenario. When done regularly, cardiological evaluation increases the chances of diagnosing ventricular pre-excitation. Consequently, the following question arises: what is the real incidence of SD risk in athletes with Wolff-Parkinson-White (WPW) syndrome/pattern? This study included 84 consecutive patients diagnosed with WPW and was designed as a retrospective analysis of data acquired between 2011 and 2021 to answer this question. The patients were evaluated using a 12-lead electrocardiogram (ECG), echocardiography, stress test, and electrophysiological study (EPS). The SD risk linked to WPW was defined as ≥ 1 of the following: the anterograde effective refractory period (AERP) of the accessory pathway (AP) ≤ 250 ms, atrial fibrillation (AF) with the shortest RR pre-excited interval ≤ 250 ms, syncope during AF or atrioventricular reentry tachycardia. The athletes with WPW pattern (n=25) or syndrome (n=59) at risk of SD were identified and treated with radiofrequency ablation (RFA). The mean age was 19.83 (10–29) years; 66.6% were men. Seventeen athletes (n=17; 20.23%) were found with SD risk: 15 (n=15; 17.85%) in the WPW syndrome group and 2 (n=2; 2.38%) in the WPW pattern group. During the EPS, n=4 developed syncope: 1 during antidromic tachycardia and 3 during pre-excited AF. RFA was curative in 96.42% of cases. The EPS is mandatory to identify athletes with short AERP APs linked to an increased risk of SD. RFA is the intervention that settles the patients into a risk-free area, allowing resumption of sports shortly afterward.

Non-specific intraventricular conduction delay and ventricular pre-excitation: “Pseudo-P wave”, warning for it!

Atrial fibrillation (AF) is the most common cardiac arrhythmia in adults with substantial morbidity and mortality. The diagnosis of AF is established by electrocardiogram showing heart rhythm without clear P waves with irregular RR intervals. The electrocardiographic diagnosis of AF is not always easy and can still hide pitfalls even for the most experienced cardiologist. We present the case of an 86 years old patient admitted to our hospital for Covid-19 infection affected by dilated cardiomyopathy with an electrocardiogram showing a non-specific intraventricular conduction delay mimicking sinus rhythm in the presence of AF.

P34 ASYMPTOMATIC VENTRICULAR PRE–EXCITATION WITH DISAPPEARANCE DURING EXERTION: ALWAYS AN INDEX OF BENIGNITY?

Abstract Introduction The disappearance of pre–excitation at high heart rates points to a low arrhythmic risk: why resort to electrophysiological studies anyway? Clinical Case L.S., a 12–year–old patient, performed an ECG for sports examination with evidence of ventricular pre–excitation from an asymptomatic left lateral accessory route (Fig. A). A 24 h ECG–Holter during training showed the disappearance of the pre–excitation at high frequencies (Fig. B) which is considered a low risk index. The patient underwent a transesophageal electrophysiological study (SETE) during which an effective refractory antegrade period of 228 ms of the pathway was objectified through atrial extrastimuli (*) (Fig. C: drive of atrial stimuli (*) followed by extrastimulus with conduction on an accessory route (E)). In addition, a 1: 1 conduction was observed on the atrial pathway up to at least 270 bpm (222 ms). The antegrade refractory period of the resting path was &amp;lt;250 ms and therefore identified a high–risk condition to be treated with ablation. Discussion The disappearance of pre–excitation at high heart rates is usually considered indicative of an accessory pathway with a long refractory period and therefore at low risk, however it must be sudden. According to European guidelines, the execution of invasive studies in asymptomatic patients who are employed in high–risk jobs or competitive sports has a class I B indication, but in the remaining asymptomatic cases the indication is IIa B. The Holter ECG alone or the stress test, with a careless evaluation of the disappearance of the pre–excitation (sudden vs progressive with minimal residual pre–excitation) would have erroneously led to labeling this accessory pathway at low risk. In the left lateral accessory pathways, with the increase of the HR, there can be a disappearance or pseudo–disappearance of the pre–excitation for anatomical reasons (being further away from the SA node) and for an increase in the AV conduction speed, not therefore for a long refractory period of the pathway. SETE is closer to the atrial side of the left accessory pathway and allows to correctly classify the risk. Conclusion SETE is a low–cost and minimally invasive method that should be considered as an integral part of the study of patients with asymptomatic ventricular pre–excitation even if non–invasive stratification indicates low risk.

P408 CERTIFICATION FOR COMPETITIVE SPORTS ACTIVITY IN A TEENAGER WITH WPW BY VIA INTRAHYSSIAN ACCESSORY PATHWAY

Abstract The case of a 12–year–old male, height 160 cm, weight 46 kg, who practices water polo at a competitive level is reported. Negative family history of cardiovascular pathologies, general and cardiovascular physical examination within the limits of normality. On the electrocardiographic trace (ECG) presence of delta wave from ventricular pre–excitation from intrahyssian accessory pathway (Fig. 1). Echocardiography + color Doppler was normal. The subject underwent a cardiopulmonary stress test with an incremental ramp protocol and steps of 20 watts / min. Shutdown at 190 watts for muscle exhaustion with peak oxygen consumption (VO2) = 43.9 mL / Kg / min, Heart rate = 197 beats / minute, BP = 210/70 mmHg, VE / VCO2 slope = 27.6. Normal course of the cronotropic and pressure curve. The ventricular pre–excitation delta wave persisted for the entire duration of the test and in recovery (Fig. 2, Fig. 3). Secondary disturbances of ventricular repolarization characterized by ST segment sub–leveling and negative T wave appeared at high load and persisted in the first minutes of recovery, delta VO2 / delta WR = 12. Given the non–disappearance of the delta wave from ventricular pre–excitation during the maximal stress test, the subject was sent to an electrophysiological study and subsequent ablation of the accessory pathway. The electrophysiological study was negative for inducibility of atrial fibrillation (AF) and ventricular arrhythmias. Safe ablation was impossible given the intrahyssian position of the accessory pathway. Considering the negativity of the electrophysiological study due to non inducibility of supraventricular and ventricular arrhythmias, eligibility for competitive sports was granted.

P5 ACCESSORY PATHWAYS HIGH–DENSITY MAPPING IN WOLFF–PARKINSON–WHITE SYNDROME

Abstract Wolff–Parkinson–White syndrome is a common condition characterized by atrioventricular accessory pathways (AP), which can be asymptomatic or can be responsible for atrioventricular reentrant tachycardia or rapid conduction of atrial fibrillation to the ventricles: for this reason, patients are referred for catheter ablation procedures. Although success rates of ablation are &amp;gt;95%, late recurrences can occur in 2–21% of cases mainly depending on the anatomical position. Current approaches remain suboptimal, and when failures occur, they may be due to technical difficulties such as poor contact or catheter stability, inability to access the target site as well as mapping errors resulting in inaccurate location of the AP itself. High–density mapping represents an alternative approach to mapping arrhythmias since the collection of a high density of points allows pathway conduction to be mapped more efficiently. The use of a new software called open–window mapping proved to be reliable in the localization of AP and therefore in the determination of the effective ablation site. A 41–year–old male patient was referred to our Centre following the ECG finding of manifest ventricular preexcitation and short–lasting paroxysmal palpitations. In the Electrophysiology Lab, the diagnostic catheters were inserted with the “fluoroless” technique using the EnSite Precision™ mapping system (Abbott): the ECG and the endocavitary electrograms were indicative of a right Parahissian accessory pathway. The mapping was performed with a multipolar catheter (Advisor™ HD Grid). Once the location of the pathway had been estimated, the roving acquisition interval (RAI) was set according to the expected position of atrial and ventricular electrogram. The RAI window was centered at this point and was opened in both directions (open window mapping) to fully include signals leading up to and traveling away from the AP. It accurately showed the location of the pathway just few millimeters from the Hissian potential. The baseline electrophysiological study revealed an effective antegrade refractory period (PREAP) of 320 msec. In isoproterenol, antegrade PREAP was reduced to 300 msec and inducibility of arrhythmias was not observed. Therefore, in consideration of the poor conductive properties and the non–inducibility of arrhythmias, as well as the anatomical site near the conduction system, it was decided not to proceed with the ablation due to the significant risk of atrio–ventricular block.

Centres of sports cardiology in Czechia - first experiences

Abstract Funding Acknowledgements Type of funding sources: None. Background/Introduction Sports cardiology is a subspeciality of cardiology. It differs from general cardiology practice; the presence of an athlete’s heart can be challenging to differentiate from incipient cardiac pathologies, and athletes often present with atypical symptoms and expectations. In Czechia, three Centres of Sports Cardiology (CSC) for athletes older than 15 years and one for children were founded 2020 and endorsed by the Czech Society of Cardiology and the Czech Society of Sports medicine. Purpose The present study aims to share our experience from the first two years of functioning two tertiary sport cardiology centres (Centre 1 and Centre 2) Methods Only athletes registered for the examination from 1st January 2020 till 7th November 2021 were included. Results We included 149 athletes (79 from Centre 1 and 71 from Centre 2). The mean age was 29 ± 13 years. The majority of sports were mixed (n= 83) than endurance (n=58) and very few power (n=3) and skill sports (n=1). The main reason for examination was abnormal preparticipation screening results (n=46), symptoms (n=45) and abnormal findings on complementary examination (n=31). Only two athletes were indicated from cascade screening and one athlete after sudden cardiac arrest. In CSC we performed electrocardiograms (n=101), echocardiography (n=77), HolterECG (n=39), 24-hour ambulatory blood pressure monitoring (n=3), cardiac magnetic resonance (n=13) one CT-coronary angiography, cardiopulmonary exercise stress test (n=41), invasive coronary angiography (n=3), other examination (n=15). We were able to ascertain a diagnosis in 113 athletes; a suspected diagnosis was in 14 athletes, and in 20, we were unable to set any diagnosis. The main conclusions were that 79 (53%) of athletes were eligible to sport participation, in 34 (23%) of athletes, the eligibility had a condition, and only 10 (6.7 %) athletes were ineligible to sport participation. (However, the main conclusions were that 79 (53%) of athletes were eligible to sport participation, in 34 (23%) of athletes, the eligibility had a condition, and only 10 (6.7 %) athletes were ineligible to sport participation. ) The ineligibility was due to cardiomyopathy (n=5), long QT syndrome (n=2), valvular heart disease (n=1), Marfan syndrome (n=1), preexcitation syndrome (n=1). Only six athletes were lost to follow-up, and in 13 (8.7 %), the examination process was not yet closed. Conclusion(s) The establishment of sports cardiology centres in Czechia respects the global trend in cardiovascular care for athletes. The first 22 months of their work confirm the importance of their existence with the centralization of subspecialty cardiology care. Confirmation of the trend is the establishment of full eligibility in 76% of examined athletes. Similarly, the non-recommendation of further sports activity in less than 7% of examined athletes again confirms the correctness of the existence of sports cardiology centres.

Echocardiographic characteristics of PRKAG2 syndrome: a research using three-dimensional speckle tracking echocardiography compared with sarcomeric hypertrophic cardiomyopathy

BackgroundPRKAG2 syndrome is a rare disease characterized as left ventricular hypertrophy (LVH), ventricular preexcitation syndrome, and sudden cardiac death. Its natural course, treatment, and prognosis were significantly different from sarcomeric hypertrophic cardiomyopathy (HCM). However, it is often clinically misdiagnosed as sarcomeric HCM. PRKAG2 patients tend to experience delayed treatment. The delay may lead to adverse outcomes. This study aimed to identify the echocardiographic parameters which can differentiate PRKAG2 syndrome from sarcomeric HCM.MethodsNine PRKAG2 patients with LVH, 41 HCM patients with sarcomere gene mutations, and 202 healthy volunteers were enrolled. Clinical characteristics, conventional echocardiography, and three-dimensional images were recorded, and reviewed by an attending cardiologist. We evaluated the parameters of left ventricular strains from three-dimensional speckle tracking echocardiography (3D STE) by TomTec software. Receiver operating characteristic (ROC) curves analysis was used to assess clinical and echocardiographic parameters’ differential diagnosis potential.ResultsThe heart rate (HR) of the PRKAG2 group was significantly lower than both the healthy group (53.11 ± 10.14 vs. 69.22 ± 10.48 bpm, P < 0.001) and the sarcomeric HCM group (53.11 ± 10.14 vs. 67.23 ± 10.32 bpm, P = 0.001). The PRKAG2 group had similar interventricular septal thickness (IVS), posterior wall thickness (PWT), and maximum wall thickness (MWT) to the HCM group (P > 0.05). The absolute value of GLS in the PRKAG2 group was significantly higher than HCM patients (-18.92 ± 4.98 vs. -13.43 ± 4.30%, P = 0.004). SV calculated from EDV and ESV in PRKAG2 syndrome showed a higher value than sarcomeric HCM (61.83 ± 13.52 vs. 44.96 ± 17.53%, P = 0.020). The area under the ROC curve (AUC) for HR + GLS was 0.911 (0.803 -1). For HR + GLS, the sensitivity and specificity of the best cut-off value (0.114) were 69.0% and 100%, respectively.ConclusionsPRKAG2 patients present deteriorated LV diastolic function and preserved LV systolic function. Bradycardia and preserved GLS are useful to identify PRKAG2 syndrome from sarcomeric HCM, which may be beneficial for clinical decision-making.

PO-674-04 ANTICOAGULATION MANAGEMENT AND RISK OF THROMBOEMBOLISM IN HEALTHY YOUTH WITH ATRIAL FIBRILLATION: DATA FROM A MULTI-INSTITUTIONAL PACES COLLABORATIVE REGISTRY

Stroke is a well-defined complication of atrial fibrillation (AF) in adults. However, the risk of thromboembolism and need for anticoagulation therapy in children and young adults with AF are unknown. To describe the current anticoagulation practice and assess the risk of thrombosis in children and young adults with AF across 13 pediatric heart centers. Data was obtained from the multi-institutional PACES collaborative registry on atrial fibrillation. Patients ≤ 21 years of age with documented AF of an unknown cause from January 2004 to December 2018 were included. We included patients with AF with no structural heart disease, cardiomyopathy, ventricular pre-excitation, history of open heart surgery, hypertension, or thyroid disease. Of 241 subjects, 76 were prescribed oral anticoagulation at diagnosis and an additional 15 at time of AF recurrence. Aspirin was prescribed in 66 (73%) patients, warfarin in 14 (15%), novel oral anticoagulant in 7 (8%), combined therapy in 3 (3%), and unknown in 1 (1%). In a multivariable model, patients were less likely to be anticoagulated at a freestanding children’s hospital (OR 0.44, 95%CI [0.23-0.78], p=0.005) or if they had spontaneous cardioversion (OR 0.53, 95%CI [0.29-0.96], p=0.037), and more likely if prescribed an antiarrhythmic at time of initial diagnosis (OR 1.82, 95%CI [1.01-3.3], p=0.047). There was a trend towards anticoagulation in patients presenting with asymptomatic AF (OR 0.45, 95%CI [0.19-1.03], p=0.06]). Age at diagnosis, gender, and BMI were not associated with anticoagulation status. One patient (1/241, 0.4%) was found to have left atrial thrombus confirmed by transesophageal echocardiogram at time of presentation. This patient was treated with warfarin for 3 months and repeat echocardiogram showed thrombus resolution. No patient developed thromboembolic phenomenon over a mean follow up of 2.1 ± 2.6 years. Our study is the first to demonstrate that there is large practice variation in anticoagulation management with patients treated at a free-standing children’s hospital being less likely to be anticoagulated. AF associated thrombosis is rare in children and young adults.

PO-663-07 IMPACT OF INTRINSIC AND PACED PARAMETERS ON BEST ELECTRICAL RESYNCHRONIZATION IN CARDIAC RESYNCHRONIZATION THERAPY IN PATIENTS WITH HEART FAILURE AND LBBB

Electrical factors that may influence efficacy of cardiac resynchronization therapy (CRT) are transseptal conduction time during intrinsic conduction (the source of QRS prolongation in LBBB), success of left ventricular (LV) preexcitation during LV pacing, and programmed AV interval. These have been tested separately, and whether they are co-dependent is unknown.

Atrial Fibrillation with Ventricular Pre-Excitation: A Diagnosis That Must Not Be Missed

Wolff-Parkinson-White (WPW) syndrome is caused by an accessory pathway that communicates between the atria and ventricles known as the Bundle of Kent. The development of atrial fibrillation, can result in the atrial impulses all being conducted via the accessory pathway and result in a sinister, board complex, irregular tachycardia, with varying QRS morphology (known as pre-excited atrial fibrillation) Adenosine is a potent atrioventricular node blocker, which can be used in the treatment of supraventricular tachycardias, but also has diagnostic utility, particularly in differentiating between supraventricular tachycardia with aberrant conduction (which would often terminate) and a ventricular tachycardia (which would not respond to adenosine). However, the administration of adenosine in pre-excited atrial fibrillation can precipitate 1:1 atrial to ventricular conduction, which can degenerate into life-threatening ventricular arrythmias. This case describes a patient who presented with pre-excited atrial fibrillation and received intravenous adenosine that resulted in development of broad complex tachycardia with haemodynamic compromise. In patients with pre-exited atrial fibrillation, AV nodal blocking agents should be avoided and direct current cardioversion should be utilised.

Aneurismas gigantes assintomáticos na artéria coronária direita

An 11-year-old male patient with a clinical history of psychomotor development delay and ventricular preexcitation required several follow-up visits at another service. No other cardiovascular-associated symptoms were described. Since the family moved home, the child was referred to our hospital. A transthoracic echocardiogram (TTE) was performed as part of standard evaluation in the first appointment, revealing anatomical changes of the coronary arteries. Further investigation included cardiac computed tomography (CT) which showed multiple aneurysmal dilations along the path of the right [...]

Drug therapy monitoring (TDM) of Digoxin: safety and efficacy review

Digoxin was developed as a novel medication for the treatment of heart failure and atrial fibrillation (AF) 200 years ago. This investigation began with a PubMed and Google Scholar search for various papers using the terms digoxin safety and efficacy, digoxin in heart failure, and digoxin in atrial fibrillation. Digoxin should be administered at a dose of 0.5–0.7 ng/mL in individuals with heart failure and reduced ejection fraction. Digoxin should be administered to decrease hospital readmissions, although SDC, creatinine, and potassium levels should be continuously maintained to limit the risk of toxicity. Digoxin may be used in conjunction with diuretics, spironolactone, ACE inhibitors, or beta-blockers. It is preferable to take digoxin on a regular basis. Digoxin should not be used in the pre-excitation syndrome because it can result in the rapid development of accessory route conductors, which can finally result in ventricular fibrillation. Due to the narrow therapeutic index of digoxin, it requires appropriate treatment and continuous monitoring.

Atrial Lesions in a Pedigree With PRKAG2 Cardiomyopathy: Involvement of Disrupted AMP-Activated Protein Kinase Signaling.

PRKAG2 cardiomyopathy is a rare progressive disease characterized by increased ventricular wall thickness and preexcitation. Dysfunction of the protein 5′-AMP-activated protein kinase (AMPK) plays a decisive role in the progression of ventricular lesions. Although patients with the PRKAG2-R302Q mutation have a high incidence of atrial fibrillation (AF), the molecular mechanism contributing to the disease remains unclear. We carried out whole-genome sequencing with linkage analysis in three affected members of a family. Atrial samples were obtained from the proband via surgical intervention. Control atrium biopsies were obtained from patients with persistent AF. Pathological changes were analyzed using the hematoxylin and eosin (H&E), Masson, and periodic acid–Schiff (PAS) staining. The AMPK signaling pathway was investigated by western blot. A murine atrial cardiomyocyte cell line (HL-1) and human induced pluripotent stem derived atrial cardiomyocytes (hiPSC-ACMs) were transfected with an adenovirus carrying the same mutation. We used enzyme linked immunosorbent assay (ELISA) to determine the AMPK activity in HL-1 cells and hiPSC-ACMs overexpressing PRKAG2-R302Q. Pathological results showed a large quantity of glycogen accumulation and vacuolization in cardiomyocytes from the proband atrial tissue. Western blot analysis revealed that the AMPK activity was significantly downregulated compared with that of the controls. Furthermore, remarkable glycogen deposition and impairment of AMPK activity were reproduced in HL-1 cells overexpressing PRKAG2-R302Q. Taken together, PRKAG2-R302Q mutation directly impair atrial cardiomyocytes. PRKAG2-R302Q mutation lead to glycogen deposition and promote the growth of atrial lesions by disrupting the AMPK pathway.

Success rate and safety of catheter ablation in preexcitation syndrome: A comparison between adult and pediatric patients.

BackgroundIn contrast to adults, in whom cardiac rhythm disorders are mainly conditioned by coronary artery disease, in children, arrhythmias are most often associated with inherited heart disorders. Catheter ablation (CA) has an important role in the management of cardiac arrhythmias, in adults and children. The aim of the study was to assess and compare the efficacy and safety of CA in children and adults with preexcitation syndrome.MethodsThe study population comprised 43 adults and 43 children diagnosed with a Wolff-Parkinson-White syndrome (WPW). The mean age of the study population was 41 ± 15 years for adults and 14 ± 2.5 years for children. In all patients, an electrophysiological study and CA were performed. Analysis with respect to the procedure duration, fluoroscopy exposure time, location of accessory pathways (AP), immediate success rate and complications were performed.ResultsElectrophysiological study revealed the most frequent presence of left-sided AP (56% in children and 70% in adults). The mean procedure duration was 96 ± 36 min and 106 ± 51 min in children and adults, respectively (p = NS). The mean fluoroscopy duration was 8.5 ± 4.3 min and 5.9 ± 5.8 min in children and adults, respectively p < 0.05. The CA procedure was successful in 40 out of 43 (93%) adults and in 36 out of 43 (83.7%) children (p = NS). In 2 (4%) children minor complications occurred.ConclusionsAblation in children and adults are equally effective with respect to short-term clinical observation.

A Frequent Observation of Wolff-Parkinson-White Syndrome and Fasciculoventricular Pathways in Patients With Danon Disease.

Danon disease is typically associated with cardiomyopathy and ventricular pre-excitation. The study aimed to characterize the clinical profile of Danon disease, analyze electrocardiographic (ECG) and electrophysiologic features, and investigate their association with Wolff-Parkinson-White (WPW) syndrome and fasciculoventricular pathways (FVPs).Methods and Results:Clinical course, family history, ECG and electrophysiological data were collected from 16 patients with Danon disease. Over 0.4-8 years of follow up, 1 female patient died suddenly, and 5 male patients died of progressive heart failure by age 13-20 years. Family history analysis revealed that 3 mothers experienced hospitalization or death for heart failure at age 28-41 years. There was 100% penetrance for ECG abnormalities in 13 patients with original ECGs. Short PR intervals and delta waves were present in 9 and 8 patients, respectively. There were significant age-associated increases in the QRS complex width (r=0.556, P=0.048) and the number of leads with notched QRS (r=0.575, P=0.04). Four patients who underwent electrophysiological studies all had FVPs, and 2 of them still had left-side atrioventricular pathways. Danon disease causes a malignant clinical course characterized by early death caused by heart failure in both genders and progressive ECG changes as patients age. The pre-excited ECG pattern is related to FVPs and WPW, which is suggestive of extensive cardiac involvement.

Miniseries 1—Part IV: How frequent are fasciculo-ventricular connections in the normal heart?

Abstract Aims Seeking to account for accessory atrioventricular conduction potentially leading to ventricular pre-excitation, Mahaim in the mid-20th century had described pathways between the atrioventricular conduction axis and the muscular ventricular septum. We aimed to look for such ‘paraspecific’ connections in adult human hearts. Methods and results We serially sectioned 21 hearts, covering the triangle of Koch and the aortic root, and assessing the atrioventricular node, the penetration of the conduction axis, and the bundle branches in our search for fasciculo-ventricular connections. We also calculated the length of the non-branching bundle, and if present the origin of the fasciculo-ventricular connections. The non-branching bundle was 3.6 ± 1.7 mmin length, varying from 1.7 mm to 7.2 mm. Fasciculo-ventricular connections were found in more than half of the hearts, making direct contact with the muscular septum at an average of 3.5 ± 1.7 mm from the origin of the left bundle branch, with the site of origin varying from 1.1 mm to 5.5 mm from the first fascicle of the left bundle branch. In three hearts, additional fasciculo-fascicular connections were observed in the left bundle branch. Two loops were small, but one loop extended over 9.5 mm. Conclusion We endorse the finding of Mahaim that fasciculo-ventricular pathways exist in most human hearts. We presume the identified connections had the capability of producing ventricular pre-excitation. More studies are needed to determine the potential clinical manifestations.