Comparison of Electrophysiologic Profiles in Pediatric Patients with Incidentally Identified Pre-Excitation Compared with Wolff-Parkinson-White Syndrome.

The rising utilization of screening electrocardiograms has resulted in increased incidental identification of ventricular pre-excitation in pediatric patients. We compared accessory pathways of incidentally identified pre-excitation to Wolff-Parkinson-White Syndrome (WPW) with the aim to identify factors important in preprocedural counseling and planning. This single-center, retrospective study of patients ≤18 years without congenital heart disease identified 227 patients diagnosed with pre-excitation and referred for invasive electrophysiology study between 2008 and 2017. WPW Syndrome was diagnosed in 178 patients, while 49 patients had incidental identification of pre-excitation. Anterograde conduction of incidentally identified accessory pathways was not clinically different between the two cohorts at baseline or upon isoproterenol infusion. However, the proportion of accessory pathways meeting high-risk criteria was significantly lower than in patients diagnosed with WPW, 12% versus 28% (p < 0.05). Retrograde conduction at baseline of incidentally diagnosed accessory pathways was slower with a median block cycle length 365 milliseconds (IQR 260 to 450) versus 290 milliseconds (IQR 260 to 330, p < 0.01). In the incidentally identified cohort, right-sided, paraHisian, and fascicular pathways were more common with fewer attempted ablations (71% vs 94%, p < 0.001) and lower success rate (91% vs 97%, p < 0.001). A binomial logistic regression analysis further indicated patients incidentally identified with pre-excitation were associated with having lower rates of inducible supraventricular tachycardia, atrial fibrillation, and ablations performed, in addition, to having right-sided pathways. In conclusion, as patients with incidentally identified pre-excitation present more frequently for consideration of invasive electrophysiology study, these results impact procedural approaches, technical considerations, patient counseling, and outcome expectations.

Classical response of antidromic atriofascicular tachycardia to premature atrial extrastimulus delivered during septal refractoriness.

A 23-year-old gentleman presented with a history of palpitations. The 12-lead electrocardiogram showed no manifest ventricular pre-excitation. Echocardiogram was within normal limits. A retrograde study showed concentric activation of the atrium with decremental conduction. Atrial pacing from right atrial free wall showed progressive pre-excitation. No anterograde nodal duality was documented.

Pulseless Electric Activity with Pre-Excitation.

A 41-year-old man developed cardiac arrest. A resting 12-lead electrocardiogram showed a delta wave, suggestive of preexcitation syndrome. An electrophysiological test revealed the existence of inducible atrial fibrillation and a fasciculoventricular accessory pathway (FVAP). After these examinations, idiopathic ventricular arrhythmia was suspected. For evaluating concealed Brugada syndrome, pilsicainide was administered, which diminished the delta wave and no Brugada-like electrocardiogram was observed. Ventricular double extra-stimulation from the RV apex easily induced VF, which could not be defibrillated by an external defibrillator, and later stopped spontaneously. These results established the diagnosis of FVAP and idiopathic VF, and not pre-excited atrial fibrillation or Brugada syndrome.

Coexistence of atrioventricular accessory pathways and drug-induced type 1 Brugada pattern.

BACKGROUND: Atrial arrhythmias, particularly atrioventricular nodal reentrant tachycardia, can coexist with drug-induced type 1 Brugada electrocardiogram (ECG) pattern (DI-Type1-BrP). The present study was designed to determine the prevalence of DI-Type1-BrP in patients with atrioventricular accessory pathways (AV-APs) and to investigate the clinical, electrocardiographic, electrophysiologic, and genetic characteristics of these patients. METHODS: One-hundred twenty-four consecutive cases of AV-APs and 84 controls underwent an ajmaline challenge test to unmask DI-Type1-BrP. Genetic screening and analysis was performed in 55 of the cases (19 with and 36 without DI-Type1-BrP). RESULTS: Patients with AV-APs were significantly more likely than controls to have a Type1-BrP unmasked (16.1 vs 4.8%, P = 0.012). At baseline, patients with DI-Type1-BrP had higher prevalence of chest pain, QR/rSr' pattern in V1 and QRS notching/slurring in V2 and aVL during preexcitation, rSr' pattern in V1 -V2 , and QRS notching/slurring in aVL during orthodromic atrioventricular reentrant tachycardia (AVRT) compared to patients without DI-Type1-BrP. Abnormal QRS configuration (QRS notching/slurring and/or fragmentation) in V2 during preexcitation was present in all patients with DI-Type1 BrP. The prevalence of spontaneous preexcited atrial fibrillation (AF) and history of AF were similar (15% vs 18.3%, P = 0.726) in patients with and without DI-Type1-BrP, respectively. The prevalence of mutations in Brugada-susceptibility genes was higher (36.8% vs 8.3%, P = 0.02) in patients with DI-Type1-BrP compared to patients without DI-Type1-BrP. CONCLUSIONS: DI-Type1-BrP is relatively common in patients with AV-APs. We identify 12-lead ECG characteristics during preexcitation and orthodromic AVRT that point to an underlying type1-BrP, portending an increased probability for development of malignant arrhythmias.

Heart rate variability parameters in children with ventricular preexcitation.

INTRODUCTION: The autonomic nervous system has a regulatory effect on cardiac electrophysiology and arrhythmogenesis. We aimed to assess cardiac autonomic status using heart rate variability (HRV) parameters in children with ventricular preexcitation. METHODS: The electrocardiography, Holter monitoring, transesophageal electrophysiological study (TEEPS), and invasive electrophysiological study (EPS) results of ventricular preexcitation patients obtained over a 7-year period in our clinic were evaluated. According to the TEEPS results, patients' accessory pathway conduction was classified as adverse (n = 40) or nonadverse (n = 25). The HRV parameters of patients were compared according to tachycardia inducibility that assessed by TEEPS and EPS. Also, HRV parameters were compared in patients with adverse and nonadverse pathway conduction. Further, the HRV parameters of preexcitation patients were compared with those of healthy controls. RESULTS: LF/HF, the best measure of sympathovagal balance, was statistically higher in patients with adverse conduction than in patients without adverse conduction and controls (P  =  0.001). The LF/HF ratio was higher in ventricular preexcitation patients with inducible tachycardia than those without in EPS (P  =  0.001). In addition, the LF/HF ratio was higher in symptomatic ventricular preexcitation patients than asymptomatic ones (P  =  0.001). No difference in HRV parameters was found between preexcitation patients and controls. CONCLUSION: Autonomic tonus in patients with ventricular preexcitation may affect accessory pathway conduction properties, tachycardia inducibility, and symptomology. The indicator of sympathovagal balance, LF/HF ratio, increased in ventricular preexcitation patients with inducible tachycardia and those that were symptomatic.

Intermittent preexcitation indicates "a low-risk" accessory pathway: Time for a paradigm shift?

We report three patients with intermittent loss of the preexcitation pattern in the ECG that had undergone an electrophysiological study. Despite apparently poorly conducting accessory pathway (AP), in each case a fast anterograde conduction, either during spontaneous atrial fibrillation or during incremental atrial pacing (on isoproterenol) was documented; shortest preexcited RR intervals of 200-240 ms were observed. We review the literature and conclude that intermittent preexcitation observed on resting 12-lead ECG lacks sufficient specificity for the diagnosis of an AP with long refractory period and cannot be considered a substitute for electrophysiological study in patients with this electrocardiographical phenomenon.

Influence of advancing age on clinical presentation, treatment efficacy and safety, and long-term outcome of pre-excitation syndromes: a retrospective cohort study of 961 patients included over a 25-year period.

OBJECTIVES: There are very little data on pre-excitation syndrome (PS) in the elderly. We investigated the influence of advancing age on clinical presentation, treatment and long-term outcome of PS. SETTING: Single-centre retrospective study of patient files. PARTICIPANTS: In all, 961 patients (72 patients ≥60 years (mean 68.5±6), 889 patients <60 years (mean 30.5±14)) referred for overt pre-excitation and indication for electrophysiological study (EPS) were followed for 5.3±5 years. Usual care included 24 h Holter monitoring, echocardiography and EPS. Patients underwent accessory pathway (AP) ablation if necessary. PRIMARY AND SECONDARY OUTCOME MEASURES: Occurrence of atrial fibrillation (AF) or procedure-induced adverse event. RESULTS: Electrophysiological data and recourse to AP ablation (43% vs 48.5%, p=0.375) did not significantly differ between the groups. Older patients more often had symptomatic forms (81% vs 63%, p=0.003), history of spontaneous AF (8% vs 3%, p=0.01) or adverse presentation (poorly tolerated arrhythmias: 18% vs 7%, p=0.0009). In multivariable analysis, patients ≥60 years had a significantly higher risk of history of AF (OR=4.2, 2.1 to 8.3, p=0.001) and poorly tolerated arrhythmias (OR=3.8, 1.8 to 8.1, p=0.001). Age ≥60 years was associated with an increased major AP ablation complication risk (10% vs 1.9%, p=0.006). During follow-up, occurrence of AF (13.9% vs 3.6%, p<0.001) and incidence of poorly tolerated tachycardia (4.2% vs 0.6%, p=0.001) were more frequent in patients ≥60 years, although frequency of ablation failure or recurrence was similar (20% vs 15.5%, p=0.52). In multivariable analysis, patients ≥60 years had a significantly higher risk of AF (OR=2.9, 1.2 to 6.8, p≤0.01). CONCLUSIONS: In this retrospective monocentre study, patients ≥60 years referred for PS work up appeared at higher risk of AF and adverse presentation, both prior and after the work up. These results suggest that, in elderly patients, the decision for EPS and AP ablation should be discussed in light of their suspected higher risk of events and ablation complications. However, these findings should be further validated in future prospective multicentre studies.

Sports Eligibility After Risk Assessment and Treatment in Children with Asymptomatic Ventricular Pre-excitation.

BACKGROUND AND OBJECTIVE: Many studies concern the management of young patients with symptomatic Wolff-Parkinson-White (WPW) syndrome, but little information exists on the significance and prognosis of ventricular pre-excitation (VPE) in asymptomatic children. The aim of the study was to evaluate the risk of sudden death in young athletes with asymptomatic VPE by transesophageal electrophysiological study (TEEPS) and their sports eligibility after the risk assessment and/or ablative treatment. METHODS: Ninety-one asymptomatic children and adolescents underwent TEEPS both at rest and during adrenergic stress (exercise testing or isoproterenol infusion). After electrophysiological testing, patients were assessed in the 36 months of follow-up. RESULTS: Thirty-three patients (36.3 %) had a benign form of VPE and were allowed to participate in competitions. Ten patients (11 %) were at borderline risk; thus, sport eligibility was evaluated individually. Forty-eight patients (52.7 %) showed inducible sustained atrioventricular reentrant tachycardia and/or atrial fibrillation (AF), 11 of whom (12.1 % of total population) had a potential risk of sudden cardiac death due to AF inducibility during physical stress. Forty-five young athletes underwent transcatheter ablation (TCA). TCA was interrupted in 12 patients (26.7 %) because of the high procedural risk linked to septal accessory pathway (AP) location. There were no TCA-related complications, and all patients remained asymptomatic during follow-up. CONCLUSION: Most of the young athletes with asymptomatic VPE may be allowed to participate in competitive sports after an adequate risk assessment and/or ablative treatment. However, in our opinion, special care should be taken to avoid procedural complications, which are unacceptable in asymptomatic patients.

Pre-excitation syndrome with a change in terminal QRS vector.

Most accessory pathways in pre-excitation syndrome are capable of antegrade conduction from atrium to ventricle, and identified by characteristic ECG abnormalities such as a delta wave (ventricular pre-excitation) and a shortened PR interval.Therefore, the traditional diagnosis method is to detect the initial changes of the QRS complex. Here we report a patient initially mistaken as having atrioventricular re-entrant tachycardia (AVRT) and concealed pre-excitation syndrome. A diagnosis of incomplete latent pre-excitation syndrome was established on the basis of differences between the ECGs during sinus rhythm and AVRT in terminal QRS vectors, demonstrated by intracardiac electrophysiological radiofrequency catheter ablation.

Induction of atrial fibrillation with adenosine during a transesophageal electrophysiology study to risk stratify a patient with asymptomatic ventricular preexcitation.

An asymptomatic adolescent male athlete was incidentally found to have ventricular preexcitation on electrocardiogram during a sports preparticipation physical. A transesophageal electrophysiology study (TEEPS) was performed after an exercise stress test failed to delineate the patient's risk of sudden cardiac death. The TEEPS was favored in this case over a transvenous electrophysiology study due to reduced invasiveness. The goal of the TEEPS was to place the patient into atrial fibrillation (AFib) and evaluate the shortest preexcited RR interval during AFib, thereby assessing the risk of his accessory pathway. Conventional pacing modalities were unable to induce AFib. During atrial burst pacing, adenosine was then administered, which successfully induced AFib. This case highlights adenosine's potential to induce atrial fibrillation during transesophageal electrophysiology studies when atrial pacing alone was unable to do so.

Atrial fibrillation induction by transesophageal electrophysiology studies in patients with asymptomatic ventricular preexcitation.

OBJECTIVE: Ventricular preexcitation is a conduction abnormality caused by an accessory pathway bridging the atria and ventricles. If the accessory pathway conducts rapidly during atrial fibrillation (AFib), sudden death may result. The purpose of this study was to determine the ability of transesophageal electrophysiology studies (TEEPS) to induce AFib in pediatric patients with asymptomatic ventricular preexcitation (aVPE). DESIGN: A retrospective review of patients with aVPE who had a TEEPS was conducted. Inclusion criteria were evidence of ventricular preexcitation on electrocardiogram; age <18 years; and no history of tachycardia, palpitations, or syncope. Data gathered included age, weight, height, form of sedation, and TEEPS results. If AFib was induced, patients were classified as at risk of sudden death if the shortest preexcited RR interval during AFib was <250 ms or no risk if ≥ 250 ms. RESULTS: A total of 26 patients met the inclusion criteria, with average age of 11.9 years, weight of 48.9 kg, and height of 149.2 cm. During the procedure, nine patients underwent conscious sedation (34.6%), and 17 underwent general anesthesia (65.4%). AFib was induced in 23 patients (88.5%), of whom 17 (73.9%) had no risk and six (26.1%) had risk. No statistical differences were noted in age, weight, height, or form of sedation when comparisons were made between AFib induction and no AFib induction. CONCLUSIONS: TEEPS induced AFib in 88.5% of patients. Age, weight, height, and form of sedation had no effect upon AFib inducibility. TEEPS is an effective modality to induce AFib in pediatric patients with aVPE.