[Historical developments in the diagnosis and treatment of pre-excitation syndromes (WPW)]. / Historische Entwicklung in Diagnostik und Therapie bei Präexzitationssyndromen (WPW).

In 1930, Wolff, Parkinson and White described the syndrome that bears their names. The mechanisms of supraventricular tachycardias were analyzed by brilliant electrocardiography interpretation by Pick and Langendorf. Wellens and Durrer using electrophysiologic studies analyzed the tachycardia mechanism invasively. In Germany the group by Seipel and Breithardt as well as Neuss and Schlepper studied the tachycardia mechanisms and response to antiarrhythmic drugs invasively by electrophysiological studies. Following the first successful interruption of an accessory pathway by Sealy in 1967, surgeons and electrophysiologists cooperated in Germany. Two centers, Hannover and Düsseldorf were established. Direct current (DC) ablation of accessory pathways was introduced by Morady and Scheinman. Because of side effects induced by barotrauma of DC, alternative strategies were studied. In 1987, radiofrequency ablation was introduced and thereafter established as curative therapy of accessory pathways in all locations.

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).

Hypertrophic Cardiomyopathy and Ventricular Preexcitation in the Young: Cause and Accessory Pathway Characteristics.

BACKGROUND: The cause of hypertrophic cardiomyopathy (HCM) in the young is highly varied. Ventricular preexcitation (preexcitation) is well recognized, yet little is known about the specificity for any cause and the characteristics of the responsible accessory pathways (AP). METHODS: Retrospective cohort study of patients <21 years of age with HCM/preexcitation from 2000 to 2022. The cause of HCM was defined as isolated HCM, storage disorder, metabolic disease, or genetic syndrome. Atrioventricular AP (true AP) were distinguished from fasciculoventricular fibers (FVF) using standard invasive electrophysiology study criteria. AP were defined as high risk if any of the following were <250 ms: shortest preexcited RR interval in atrial fibrillation, shortest paced preexcited cycle length, or anterograde AP effective refractory period. RESULTS: We identified 345 patients with HCM and 28 (8%) had preexcitation (isolated HCM, 10/220; storage disorder, 8/17; metabolic disease, 5/19; and genetic syndrome, 5/89). Six (21%) patients had clinical atrial fibrillation (1 with shortest preexcited RR interval <250 ms). Twenty-two patients underwent electrophysiology study which identified 23 true AP and 16 FVF. Preexcitation was exclusively FVF mediated in 8 (36%) patients. Five (23%) patients had AP with high-risk conduction properties (including ≥1 patient in each etiologic group). Multiple AP were seen in 8 (36%) and AP plus FVF in 10 (45%) patients. Ablation was acutely successful in 13 of 14 patients with recurrence in 3. One procedure was complicated by complete heart block after ablation of a high-risk midseptal AP. There were significant differences in QRS amplitude and delta wave amplitude between groups. There were no surface ECG features that differentiated AP from FVF. CONCLUSIONS: Young patients with HCM and preexcitation have a high likelihood of underlying storage disease or metabolic disease. Nonisolated HCM should be suspected in young patients with large QRS and delta wave amplitudes. Surface ECG is not adequate to discriminate preexcitation from a benign FVF from that secondary to potentially life-threatening AP.

Ventricular pre-excitation in cats: 17 cases.

OBJECTIVES: Atrioventricular accessory pathways are abnormal electrical connections between the atria and ventricles that predispose to ventricular pre-excitation (VPE) and tachycardias. ANIMALS: Seventeen cats with VPE and 15 healthy matched-control cats. MATERIAL AND METHODS: Multicenter case-control retrospective study. Clinical records were searched for cats with VPE, defined as preserved atrioventricular synchrony, reduced PQ interval, and increased QRS complex duration with a delta wave. Clinical, electrocardiography, echocardiographic, and outcome data were collated. RESULTS: Most cats with VPE were male (16/17 cats), non-pedigree cats (11/17 cats). Median age and mean body weight were 5.4 years (0.3-11.9 years) and 4.6 ± 0.8 kg, respectively. Clinical signs at presentation included lethargy (10/17 cats), tachypnea (6/17 cats), and/or syncope (3/17 cats). In two cats, VPE was an incidental finding. Congestive heart failure was uncommon (3/17 cats). Nine (9/17) cats had tachyarrhythmias: 7/9 cats had narrow QRS complex tachycardia and 2/9 cats had wide QRS complex tachycardia. Four cats had ventricular arrhythmias. Cats with VPE had larger left (P < 0.001) and right (P < 0.001) atria and thicker interventricular septum (P = 0.019) and left ventricular free wall (P = 0.028) than controls. Three cats had hypertrophic cardiomyopathy. Treatment included different combinations of sotalol (5/17 cats), diltiazem (5/17 cats), atenolol (4/17 cats), furosemide (4/17 cats), and platelet inhibitors (4/17 cats). Five cats died, all from cardiac death (median survival time 1882 days [2-1882 days]). CONCLUSIONS: Cats with VPE had a relatively long survival, albeit showing larger atria and thicker left ventricular walls than healthy cats.

Ablation of Ventricular Preexcitation to Cure Preexcitation-Induced Dilated Cardiomyopathy in Infants: Diagnosis and Outcome.

BACKGROUND: To investigate the clinical features of preexcitation-induced dilated cardiomyopathy in infants and evaluate safety and efficacy of radiofrequency ablation (RFCA) in these patients. METHODS: This study included 10 infants (4 males and 6 females) with mean age of 6.78±3.14 months, mean weight of 8.11±1.71 kg, and mean left ventricular ejection fraction (LVEF) was 32.6±10.34%. Tachycardiomyopathy has been excluded and all patients were refractory to the drugs. All of these 10 patients underwent RFCA. RESULTS: All the accessory pathways in these patients were located on right free wall and the acute success rate was 100%. No complication associated with the procedure occurred. In one case preexcitation recurred and was ablated successfully during the second attempt. There were 3 patients with mild cardiac dysfunction (LVEF, 40≤LVEF<50%), 3 with moderate (30≤LVEF<40%), and 4 with severe cardiac dysfunction (LVEF<30%, the ages were 3, 6, 7, and 10 months, respectively). The time for LVEF normalization was 1 week, 1 to 3 months, and ≥3 months, respectively. In 3 of the 4 severe cardiac dysfunction patients, the LVEF normalized at 3, 6, and 12 months after ablation, the LVEF of the remaining case did not recover at 3 months and is still being followed. CONCLUSIONS: Ventricular preexcitation could lead to severe cardiac dysfunction during infancy. RFCA may be a safe and effective treatment option in right free wall accessory pathways, even in infants with cardiac dysfunction. Cases of more severe cardiac dysfunction might require a longer time for LVEF recovery after RFCA.

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.

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.

Pre-excitation syndrome presenting with acute myocardial infarction.

A male in his mid 50s, chronic smoker and hypertensive for 10 years presented with history suggestive of typical angina, electrocardiographic evidence of pre-excitation and serial elevation of cardiac biomarkers. Serial electrocardiograms showed subtle changes (axis shift, horizontal ST-segment changes) that could be presumptive of an anterior wall myocardial infarction. Speckle tracking echocardiography revealed territorial reduction of longitudinal strain corresponding to the left anterior descending artery with coronary angiography corroborating the same and underwent successful revascularisation. Exercise stress testing showed abrupt and complete disappearance of delta wave and normalisation of PR interval which indicates that the patient has low risk of developing malignant arrhythmias and sudden cardiac death.

Accessory pathway properties are similar in symptomatic and asymptomatic preexcitation.

PURPOSE: Patients with WPW syndrome have an increased mortality rate compared to the general population. Although asymptomatic preexcitation has previously been considered benign, recent studies have found that also asymptomatic patients have clinical and electrophysiological factors associated with increased risk of sudden cardiac death. This study compares the baseline electrophysiological characteristics of accessory pathways in symptomatic and asymptomatic patients with preexcitation. We hypothesized that a significant proportion of asymptomatic patients has inducible orthodromic tachycardia during programmed electrical stimulation. METHODS: This retrospective study includes 1853 patients with preexcitation who underwent invasive electrophysiological testing in two Swedish University Hospitals between 1991 and 2018. The mean age was 36 ± 17 years with a range of 3-89 years. Thirty-nine percent was women. A total of 269 patients (15%) were children younger than 18 years. Electrophysiological data included effective refractory period of the accessory pathway (APERP, in 1069 patients), tachycardia cycle length, inducibility and type of tachycardia, and AP localization. RESULTS: A total of 1703 (93%) patients reported symptoms suggesting tachyarrhythmias before the study and 128 (7%) were asymptomatic. The proportion of potentially dangerous pathways with short APERP (≤ 250 ms) were similar in symptomatic and asymptomatic patients (187/949, 20% vs. 25/108, 23%) (P = 0.40) as was the mean APERP (303 ± 68 ms vs. 307 ± 75) (P = 0.61). The proportion of patients who had inducible arrhythmia was larger in the symptomatic group (64% vs. 31%) (P < 0.001). CONCLUSION: The results of this study strengthen the present guideline recommendation (IIA) to consider invasive risk assessment in patients with asymptomatic preexcitation.

Pre-excitation Due to Fascicular-Ventricular Pathway: An Electrocardiographic Diagnosis: A Case Report.

A 79-year-old Caucasian male was referred to cardiology clinic because the electrocardiogram showed premature atrial complexes and pre-excitation (delta waves) thought to be consistent with Wolff-Parkinson-White (WPW) syndrome. He did not report symptoms of palpitations or syncope. Careful analysis of the electrocardiogram revealed a fascicular-ventricular pathway (FVP) responsible for pre-excitation. Differentiating FVP from WPW syndrome is essential as the risk profile is different with each. Electrocardiographic observations that could help identify the presence of an FVP and its diagnostic, prognostic, and therapeutic implications are presented.

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.

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

BACKGROUND: In 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. METHODS: The 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. RESULTS: Electrophysiological 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. CONCLUSIONS: Ablation in children and adults are equally effective with respect to short-term clinical observation.

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.

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.