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.

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.

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.

Invasive electrophysiological evaluation and ablation in patients with asymptomatic ventricular pre-excitation persistent at exercise stress test.

AIMS: In patients with asymptomatic ventricular pre-excitation (VPE) persistent at exercise stress test, this study evaluates the proportion of cases with adverse conduction properties of the atrioventricular accessory pathway (AP) at invasive electrophysiological study and the long-term follow-up after they received treatment according to pre-determined criteria. METHODS AND RESULTS: Over 10 years, asymptomatic patients with VPE persistent at exercise stress test referred for invasive electrophysiological evaluation including isoproterenol (IPN) infusion were included. Ablation was planned if they had at least one of the following criteria: (i) shortest pre-excited R-R interval (SPERRI) ≤250 ms and/or (ii) inducible atrioventricular re-entrant tachycardia (AVRT). Cryoablation was electively used in para-hisian and mid-septal APs. Patients non-eligible for ablation received no therapy. Sixty-three patients (45 males; mean age 26 ± 14 years) underwent electrophysiological evaluation: 7 had fasciculo-ventricular fibres and were excluded, whereas 56 had 58 APs. Thirty-one patients (55%) were eligible and underwent successful ablation: 87% had at least the SPERRI ≤ 250 ms and 61% had at least inducible AVRT. In 15 cases (48%) the ablation criteria were met only during IPN infusion. During follow-up (73 ± 33 months), one patient was successfully retreated for resumption of VPE in the ablation group, whereas no event was observed in the group of patients who received no treatment. CONCLUSION: In this subset of patients with asymptomatic VPE, invasive electrophysiological evaluation shows fast antegrade conduction over the AP and/or inducible AVRT in about half of the cases. Patients who received no therapy because of a benign electrophysiological profile had an event-free follow-up.

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.

Left ventricular dyssynchrony in pre-excitation syndrome: effect of accessory pathway location and reversibility after ablation therapy.

We sought to evaluate the effects and reversibility of different locations of accessory pathways (AP) on left ventricular dyssynchrony (LVdys). The acute and chronic effects of AP were evaluated in a canine model (n = 11) and in patients with pre-excitation syndrome (n = 25). Pre-excitation was simulated in the canine model by applying VDD-type epicardial ventricular pacing near the atrioventricular (AV) groove with 50-ms AV interval after median thoracotomy, at five different sites in each animal. For the simulation of pre-excitation through the septal accessory pathway, right basal septal pacing was performed using a transvenous lead. Left ventricular dyssynchrony was measured by a two-dimensional speckle-tracking technique: before and during pacing in the canine model, and before and within 24 h after the ablation in patients with Wolff-Parkinson-White (WPW) syndrome. In the canine model, the most prominent intraventricular LVdys was observed in left lateral pre-excitation (P < 0.001). In patients with pre-excitation syndrome, LVdys was greatest in patients with left free wall accessory pathways before the ablation (P = 0.013). After catheter ablation, such a difference diminished (P = 0.619). The degree of LVdys was different according to the site of AP in both the acute model and chronic patients, and the most significant LVdys associated with pre-excitation was observed in left lateral AP. Left ventricular dyssynchrony was reversible in patients with WPW syndrome. Left ventricular dyssynchrony observed in patients with pre-excitation syndrome might be a different entity from that observed in patients with heart failure.

The natural history of asymptomatic ventricular pre-excitation a long-term prospective follow-up study of 184 asymptomatic children.

OBJECTIVES: The aim of this study was to describe the natural history of asymptomatic ventricular pre-excitation in children and to determine predictors of potentially life-threatening arrhythmic events. BACKGROUND: Sudden death can be the first clinical manifestation in asymptomatic children with ventricular pre-excitation, but reduction of its incidence by prophylactic ablation requires the identification of subjects at high risk. METHODS: Between 1995 and 2005 we prospectively collected clinical and electrophysiologic data from 184 children (66% male; median age 10 years; range 8 to 12 years) with asymptomatic ventricular pre-excitation on the electrocardiogram. After electrophysiologic testing, subjects were followed as outpatients taking no medications. The primary end point of the study was the occurrence of arrhythmic events. Predictors of potentially life-threatening arrhythmias were analyzed. RESULTS: Over a median follow-up of 57 months (min/max 32/90 months) after electrophysiologic testing, 133 children (mean age 10 years; range 8 to 12 years) did not experience arrhythmic events, remaining totally asymptomatic, while 51 children had within 20 months (min/max 8/60 months) a first arrhythmic event, which was potentially life-threatening in 19 of them (mean age 10 years; range 10 to 14 years). Life-threatening tachyarrhythmias resulted in cardiac arrest (3 patients), syncope (3 patients), atypical symptoms (8 patients), or minimal symptoms (5 patients). Univariate analysis identified tachyarrhythmia inducibility (p < 0.001), anterograde refractory period of accessory pathways (APERP)

Location of accessory connection in infants presenting with supraventricular tachycardia in utero: clinical correlations.

The most common mechanism of fetal tachycardia is orthodromic reciprocating tachycardia utilizing an accessory atrioventricular connection, however, data regarding accessory connection location in patients with fetal tachycardia is limited. To investigate the location of accessory connections in fetal tachycardia, postnatal transesophageal electrophysiology studies were performed at one institution over a 10-year period in 24 infants with documented fetal tachycardia. The 18 infants with inducible orthodromic reciprocating tachycardia were grouped according to accessory connection location, and groups were compared regarding prenatal presentation and clinical course. Left-sided connections were found in 13 (72%) patients, while accessory connection location could not be determined in the remaining 5 (28%) patients. The presence of a left-sided accessory connection was associated with sustained tachycardia, depressed ventricular function, and the need for antiarrhythmic therapy in utero. No other difference in clinical or electrophysiologic data was found between groups. Our findings indicate that a high proportion of patients with fetal tachycardia have left-sided accessory connections, and a left-sided connection may adversely affect fetal hemodynamics and cardiac output.