Risk assessment in patients with symptomatic and asymptomatic pre-excitation.

AIMS: Controversy remains as to whether the exercise stress test (EST) is sufficient for risk evaluation in patients with pre-excitation. This study aims to clarify the usefulness of EST in risk stratification in both asymptomatic and symptomatic patients presenting with pre-excitation. METHODS AND RESULTS: This prospective study includes consecutive asymptomatic and symptomatic patients with pre-excitation referred for risk assessment. All participants performed an incremental EST (bicycle) prior to an electrophysiology study (EPS). Primary data from the EST included loss of pre-excitation during exercise, and primary data from the EPS included the measurement of accessory pathway effective refractory period (APERP), shortest pre-excited RR interval (SPERRI), and inducible arrhythmia with the use of a beta-adrenergic receptor agonist if deemed necessary. One hundred and sixty-four patients (59 asymptomatic, 105 symptomatic) completed an EST and EPS. Forty-five patients (27%) demonstrated low-risk findings on EST, of which 19 were asymptomatic and 26 were symptomatic. Six patients with low-risk EST findings had SPERRI/APERP ≤ 250 ms at EPS, and two of them were asymptomatic. The sensitivity, specificity, positive predictive value, negative predictive value (NPV), and accuracy of low-risk EST for excluding patients with SPERRI/APERP ≤ 250 ms were 40, 91, 87, 51, and 60%, respectively. The number of patients with inducible arrhythmia at EPS was similar in the asymptomatic (36, 69%) and symptomatic (73, 61%) groups. CONCLUSION: Sudden loss of pre-excitation during EST has a low NPV in excluding high-risk APs. The EPS with the use of isoproterenol should be considered to accurately assess the risk of patients with pre-excitation regardless of symptoms (ClinicalTrials.gov Identifier: NCT03301935).

EPM algorithm: A stepwise approach to accessory pathway localization in ventricular pre-excitation.

BACKGROUND: Accurate estimation of accessory pathway (AP) localization in patients with ventricular pre-excitation or Wolff-Parkinson-White (WPW) syndrome remains a diagnostic challenge. Existing algorithms have contributed significantly to this area, but alternative algorithms can offer additional perspectives and approaches to AP localization. OBJECTIVE: This study introduces and evaluates the diagnostic accuracy of the EPM algorithm in AP localization, comparing it with established algorithms Arruda and EASY. METHODS: A retrospective analysis was conducted on 138 patients from Hospital São Paulo who underwent catheter ablation. Three blinded examiners assessed the EPM algorithm's diagnostic accuracy against the Arruda and EASY algorithms. The gold standard for comparison was the radioscopic position of the AP where radiofrequency ablation led to pre-excitation disappearance on the ECG. RESULTS: EPM showed a diagnostic accuracy of 51.45%, closely aligning with Arruda (53.29%) and EASY (44.69%). Adjacency accuracy for EPM was 70.67%, with Arruda at 66.18% and EASY at 72.22%. Sensitivity for EPM in distinguishing left vs. right APs was 95.73%, with a specificity of 74.33%. For identifying septal vs. lateral right APs, EPM sensitivity was 82.79% with a specificity of 46.15%. These measures were comparable to those of Arruda and EASY. Inter-observer variability was excellent for EPM, with Kappa statistics over 0.9. CONCLUSION: The EPM algorithm emerges as a reliable tool for AP localization, offering a systematic approach beneficial for therapeutic decision-making in electrophysiology. Its comparable diagnostic accuracy and excellent inter-observer variability underscore its potential clinical applicability. Future research may further validate its efficacy in a broader clinical setting.

Left ventricular dysfunction in a child with asymptomatic pre-excitation: Cure with catheter ablation.

Wolff-Parkinson-White syndrome, is known to cause left ventricular dysfunction or dilated cardiomyopathy secondary to sustained tachycardia in infants and children. However, left ventricular dysfunction secondary to pre-excitation related abnormal ventricular activation has been reported in a limited number of cases. This condition should be recognized early, as catheter ablation of the accessory pathway can permit rapid ventricular function improvement. In this paper, we present a 2.5-year-old patient diagnosed with tachycardia-free Wolff-Parkinson-White syndrome with a right free wall accessory pathway and depressed cardiac function, whose left ventricular function is completely restored after successful catheter cryoablation.

Assessment of the physical performance in children with asymptomatic pre-excitation.

AIMS: Pre-excitation syndrome can lead to recurrent supraventricular tachycardias (SVTs) and carries a risk of sudden cardiac death (SCD). However, an underestimated consequence of antegrade conduction through an accessory pathway is fusion of intrinsic and accessory conduction that causes asynchronous activation and myocardial contraction that could be a cause for cardiac dysfunction and dilation. It is not known to what extent pre-excitation affects myocardial and physical performance in those patients. The aim of the study was to assess to what degree ventricular pre-excitation affects physical performance in children, using cardio-pulmonary exercise testing (CPET). METHODS AND RESULTS: The study group consisted of 30 asymptomatic children, aged 8-17 years, with pre-excitation and no history or documentation of SVT compared to 31 healthy controls matched according to sex and age. All patients underwent routine cardiology assessment and then CPET. Echocardiography showed there were no differences in the left ventricular size and function between the study and control group. During the CPET both, patients and controls achieved maximal effort. Patients in the study group showed significantly lower values of VO2max and anaerobic threshold when compared to controls. The most affected subgroup was patients with persistent pre-excitation throughout the exercise. CONCLUSIONS: Physical performance is affected in children with pre-excitation. This effect is stronger in patients with persistent delta wave observed throughout the exercise.

The characteristics of pre-excitation syndrome concomitant with atrial tachyarrhythmia and the effect of radiofrequency ablation.

BACKGROUND: Wolff-Parkinson-White (WPW) concomitant with atrial tachyarrhythmia (ATA) has not been systemically characterized. METHODS: Detailed electroanatomical mapping of the right atrium (RA) and/or left atrium (LA) was performed using three-dimensional mapping and the accessory pathway (AP) was mapped. RESULTS: WPW syndrome with ATA was diagnosed in 11 patients (median age 60 years). The characteristic of unidirectional anterograde conduction over the AP was displayed in nine patients, six of whom were intermittent. Sustained atrial tachycardia, that is, counterclockwise atrial flutter (AFL) with a median tachycardia cycle length (TCL) of 225 (220-275) ms, was mapped in eight patients; furthermore, "figure 8" right atrial reentry was mapped with TCL 250 ms in one patient with a surgical history of ventricular septal defect repair. The remaining two patients underwent mitral annulus-dependent AT after paroxysmal atrial fibrillation (PAF) ablation and LA micro-reentry AT, respectively. In four patients, the location of the APs was left posterior. Left-lateral APs were identified in four patients. The locations of the APs in the remaining three patients were the right posterior and middle septum. All ATAs and APs were successfully ablated. After a median follow-up of 37 (15-72) months, no anterograde conduction over the AP was recorded, new onset of PAF was recorded in three patients, and all of them underwent circumferential pulmonary vein isolation. CONCLUSIONS: WPW with concomitant ATA frequently had continuous anterograde conduction over the AP with a rapid ventricular rate. Most WPWs displayed the characteristic of unidirectional anterograde conduction.

Wide complex tachycardia in a patient with non-ischemic cardiomyopathy: What is the diagnosis?

A 55-year-old male presented with acute heart failure and incessant wide complex tachycardia resembling an outflow tract ventricular tachycardia. Meticulous analysis of the electrocardiograms established the diagnosis of pre-excitation with prolonged atrio-ventricular (A-V) conduction over a decrementally conducting accessory A-V pathway. "Linking" between the accessory A-V pathway and normal A-V conduction system resulted in sustained maximal pre-excitation as well as periodic transition to normal A-V conduction without appreciable change in heart rate. Successful radiofrequency ablation of this unusual accessory A-V pathway was performed at the aortic-mitral junction. This ameliorated the mechanical dysynchrony, allowed discontinuation of hemodynamic/inotropic support, and resulted in sustained symptomatic improvement.

Fasciculoventricular pathways-A rare and innocent variant: A Retrospective study focusing on clinical and electrophysiologic characteristics.

BACKGROUND: Fasciculoventricular pathways (FVPs) are variants of pre-excitation syndrome which were investigated insufficiently because of its rarity. OBJECTIVE: This report aimed to represent one of the largest series of FVP, focusing on its clinical and electrophysiological properties. METHODS: We analyzed retrospectively 26 consecutive patients who underwent electrophysiological study (EPS) for FVP between January 1998 and June 2020. RESULTS: Among 1437 patients with accessory pathways, 26 had FVP (1.80%). All the 26 patients (100%) were males, with a mean age of 22.15 ± 3.50 years (range, 20-34 years). In the baseline electrocardiograms of the patients with FVP, pre-excitation and transitional zone were seen in leads V2 -V4 . During EPS procedures, normal AH interval and shortened HV interval were detected. All the patients had AH prolongation after atrial pacing due to atrioventricular (AV) nodal delay without change in pre-excitation degree. Five of the FVP patients (19.2%) had extra accessory pathways, all of which were ablated successfully while the FVPs were followed clinically. CONCLUSION: Fasciculoventricular pathways are uncommon variants of pre-excitation syndrome; therefore, they should be diagnosed correctly and followed up noninvasively to avoid damages.

Ventricular pre-excitation in primary care patients: Evaluation of the risk of mortality.

BACKGROUND: Ventricular pre-excitation is characterized by the presence of atrioventricular accessory pathways, predisposing to arrhythmias. Although it is well established that risk stratification in symptomatic patients should be invasive, there is a lack of evidence of the benefit in asymptomatic. OBJECTIVE: Evaluate ventricular pre-excitation in the electrocardiogram (ECG) as a risk factor for overall mortality in patients of Telehealth Network of Minas Gerais (TNMG), Brazil. METHODS: This observational study was developed with the database of digital ECGs (2010-2017) from TNMG. The electronic cohort was obtained by linking data from ECG exams and those from the national mortality information system. Only the first ECG was considered. Clinical data were self-reported, and ECGs were interpreted manually by cardiologists and automatically by the Glasgow University Interpreter software. Hazard ratio (HR) for mortality was estimated using weighted Cox regression. RESULTS: Nearly 1 665 667 patients were included (median age: 50 [Q1: 34; Q3: 63] years; 41.4% were male). In a mean follow-up of 3.7 years, the overall mortality rate was 3.1%. The prevalence of ventricular pre-excitation was 0.07%. In multivariate analysis, adjusting for sex and age, ventricular pre-excitation was not associated with an increased risk of mortality (HR: 1.41; 95% confidence interval [CI]: 0.56-3.57; p = .47) when compared to the whole sample or to patients with normal ECG (HR: 1.41; 95% CI: 0.53-4.36; p = .43). In a subanalysis on accessory pathway location, there was no evidence of a higher risk of death related to any location. CONCLUSION: Ventricular pre-excitation was not associated with an increased risk of mortality in a primary care cohort.

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.

Transition during radiofrequency ablation of manifest preexcitation. What is the mechanism?

A 45-year-old lady was evaluated for recurrent episodes of palpitation. Her 12­lead electrocardiogram (ECG) showed manifest but incomplete pre-excitation consistent with left sided accessory pathway. There was no structural heart disease by echocardiogram. She underwent an electrophysiology (EP) study after informed consent. A narrow QRS tachycardia consistent with orthodromic AV re-entry got induced. The accessory pathway was mapped to 2 'O clock of the mitral annulus (MA). While radio frequency ablation (RFA) was being performed at that site, an interesting phenomenon was observed (Figs. 1 & 2). What is the mechanism?

Pre-excitation cardiac problems in children: recognition and treatment.

The prevalence of ventricular pre-excitation is 0.07-0.2% in the pediatric population. Kent bundle is the most common atrioventricular accessory pathway and Mahaim fiber is relatively rare. Approximately, 30-60% of children with ventricular pre-excitation have onset of atrioventricular reentrant tachycardia. Persistent atrioventricular reentrant tachycardia can lead to tachycardiomyopathy. The anterograde conduction of right accessory pathway might lead to ventricular systolic dyssynchrony which might result in cardiac dysfunction even in patients with no tachycardia onset. This type of dilated cardiomyopathy was named as accessory pathway-induced dilated cardiomyopathy. Antiarrhythmic drugs can be used to acutely terminate tachycardia or taken orally to decrease tachycardia recurrence in the long term. However, antiarrhythmic drugs that can be chosen for children are quite limited. Sotalol has become a new choice. With the maturation of radiofrequency catheter ablation technique, progress in three-dimensional electro-anatomic mapping, use of cryoablation, and accumulation of experience in children with small age and weight, catheter ablation has become the first choice for children with pre-excitation syndrome.Conclusion: For ventricular pre-excitation co-exists with dilated cardiomyopathy, differential diagnosis of tachycardiomyopathy or accessory pathway-induced dilated cardiomyopathy should be considered. Catheter ablation (radiofrequency and cryoablation) is a relatively safe and effective treatment option and has become the first choice to treat children with ventricular pre-excitation. What is Known: • Persistent atrioventricular reentrant tachycardia in children can lead to tachycardiomyopathy; • Antiarrhythmic drugs that can be chosen for children are quite limited. What is New: • The anterograde conduction of right accessory pathway (not related to supraventricular tachycardia) might lead to accessory pathway-induced dilated cardiomyopathy. • Catheter ablation (including radiofrequency and cryoablation) has become the first choice for children with pre-excitation syndrome.

Fixed preexcitation during decremental atrioventricular conduction. What is the mechanism?

Fasciculoventricular pathway (FVP) is a rare form of preexcitation syndrome. A FVP connects the fascicle and the ventricle. It is indistinguishable to the common preexcitation pathways on the 12­lead electrocardiography. We herein present a case of FVP, who was with the same His-ventricular interval and QRS morphology during sinus rhythm, junctional beats and rapid atrial pacing rhythm. Using a mapping catheter at the right ventricular anterior (RV) wall, we can clearly demonstrate the activation of RV with and without FVP conduction. With FVP conduction, the RV was activated from basal wall to apex. Without FVP conduction, the activation direction was reversed.

Incessant accelerated idioventricular rhythm mimicking preexcitation.

ECG of patients with Wolf Parkinson White (WPW) syndrome may simulate other entities such as myocardial infarction, ventricular premature complexes, ventricular bigeminy, accelerated idioventricular rhythm, intermittent bundle branch block or electrical alternans. On the other hand, the opposite can also occur where these other conditions may simulate WPW. We present the case of a young patient referred for WPW ablation showing an incessant accelerated idioventricular rhythm mimicking preexcitation.

Wolff Parkinson white pattern in Danon disease: When preexcitation is not what it seems.

Danondisease is a rare genetic disorder with an X-linked dominant inheritance affecting both skeletal and cardiac muscle. Its characteristic cardiac phenotype consists on a severe, non-obstructive and concentric hypertrophic cardiomyopathy (HCM) usually associated with a Wolff-Parkinson-White (WPW) type preexcitation pattern. Whether this corresponds to the presence of an AV or another type of accessory pathways, such as fasciculoventricular pathways (FVP) remains controversial in the literature. However, we describe the case of a teenager with Danon disease and preexcitation who develops a first degree AV block without any change in his QRS morphology, fact that favors the hypothesis of the presence of a FVP. This finding has important clinical implications in the management and prognosis of these complex patients. The absence of an AV accessory pathway decreases their risk of potential SCD in the context of a fast atrial arrhythmia and their chances of having a reentrant AV tachycardia.

Manifest preexcitation with a prolonged PR interval: What is the mechanism?

A 44-year-old woman with a past history of surgical ablation of an accessory pathway presented to our facility with episodes of palpitations and dizziness. An ECG showed sinus rhythm with a prolonged PR interval and a preexcited QRS complex. An EP study revealed AV conduction through a postero-septal accessory pathway and a prolonged PR interval due to severe intra-atrial conduction delay.

Evolution of acute ST-segment elevation myocardial infarction in a patient with ventricular preexcitation.

Wolff-Parkinson-White pattern is a relatively common electrocardiographic phenomenon caused by accessory atrioventricular (AV) conduction, which can make the diagnosis of acute myocardial infarction challenging. There is little existing literature regarding the interpretation of electrocardiograms in patients with accessory AV conduction pathways who present with acute myocardial infarction. We describe a case of electrocardiographic evolution of acute ST-segment elevation myocardial infarction in a patient with Wolff-Parkinson-White pattern, review pseudo-infarction patterns, and discuss proposed mechanisms for these repolarization abnormalities.

Non-invasive Risk Stratification in Pediatric Ventricular Pre-excitation.

Children with ventricular pre-excitation are at risk for sudden death. This retrospective pediatric study identified patients > 8 years of age who had undergone electrophysiology study (EPS). Our primary objective was to determine the performance characteristics of non-invasive risk stratification. Subjects were separated into two groups. Group 1 was asymptomatic or had non-specific symptoms (palpitations, chest pain, and light headedness) without documented supraventricular tachycardia (SVT). Group 2 had syncope, documented SVT, or a life-threatening event. As a secondary aim, we tested whether patients with severe symptoms had a shorter time from the date of diagnosis to the date of invasive risk stratification. Among 93 patients with an average age of 14.2 years, 25 patients had documented SVT, 6 had syncope, and 1 had a life-threatening event. The sensitivity of non-invasive risk stratification was 7%. The specificity was 91%. The positive predictive valve was 14% and the negative predictive value was 84%. Even patients with severe symptoms commonly underwent non-invasive risk stratification prior to EPS, albeit at a lower rate (Group 1, 98%; Group 2 84%, p = 0.02). The median time to EPS was 4.2 months (Group 1) and 4.5 months (Group 2, p = 0.63). Non-invasive risk stratification was a poor predictor of invasive risk stratification. Cardiologists should counsel families about the limitations of non-invasive risk stratification and consider starting with invasive risk stratification and possible ablation. Counterintuitively, severe symptoms were not associated with a shorter time to electrophysiology study.

[Pregnancy with pre-excitation syndrome influence on pregnancy outcomes].

Objective: To investigate the characteristics of pregnancy with pre-excitation syndrome and its influence on pregnancy outcomes. Methods: A retrospective analysis was made on the clinical data of 62 cases of pregnancy complicated with pre-excitation syndrome in Beijing Anzhen Hospital from Jan. 2008 to Dec. 2008. According to whether there was a supraventricular tachycardia (SVT) in pregnancy, they were divided into two groups. There were 16 pregnant women in the SVT seizure group during pregnancy, and 46 pregnant women in no SVT seizure group, with a multi-disciplinary comprehensive diagnosis and treatment model. SPSS software was used to analyze the data and compare the gestational age, age and weight of the newborn, and then compare the pregnancy outcomes. Results: (1) The total number of deliveries in Beijing Anzhen Hospital during the study period was 21 786, and the patients with pregnancy combined with pre-excitation syndrome account for 0.28% (62/21 786). (2) Totally 44 patients (71%, 44/62) were diagnosed with pre-excitation syndrome before pregnancy, and 18 patients (29%, 18/62) were diagnosed for the first-time during pregnancy. Among patients diagnosed with pre-excitation syndrome before pregnancy, 16 patients (36%, 16/44) had seizures before pregnancy, 28 patients (64%, 28/44) had asymptomatic before pregnancy, and 4 of asymptomatic patients had SVT during pregnancy. (3) Of the 16 pregnant women in the SVT seizure group during pregnancy, 2 patients (2/16) had SVT episodes in the first trimester, 5 patients (5/16) had SVT episodes in the second trimester, 9 patients (9/16) had SVT episodes in the third trimester. In the SVT seizure group, 8 patients (8/16) had SVT episodes before pregnancy, and 8 patients (8/16) had no SVT episodes before pregnancy. There were 46 patients in the SVT seizure-free group during pregnancy, including 9 patients with SVT attacks before pregnancy and 37 patients without SVT before pregnancy. (4) Compared with the pregnant women in the SVT seizure group, the age, weight gained during pregnancy, delivery gestation week, newborn weight, and the time of the first and second labors were not statistically different between the two groups of pregnant women (all P>0.05). However, the total duration of labor in the SVT seizure group during pregnancy was shorter and pre-pregnancy weight was lower (all P<0.05). The rate of cesarean section in pregnant women with SVT attack was 12/16, and the rate of cesarean section in pregnant women without SVT was 50% (23/46; P=0.051). No pregnant woman had an arrhythmia during delivery. Conclusions: SVT episode in patients during pregnancy most occurs in the third trimester. Patients who are asymptomatic before pregnancy may also have SVT during pregnancy. Pre-excitation syndrome patients with SVT attacks during pregnancy increase adverse pregnancy outcomes. Multidisciplinary comprehensive management could effectively control pregnant women with pre-excitation syndrome, effectively reduce the occurrence of serious arrhythmia risk events during pregnancy, so that most patients could get good pregnancy outcomes.

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.