Ventricular Electrograms Research Articles

Improved external defibrillation success with shocks timed to descending phase of a right ventricular endocardial electrogram

Improved external defibrillation success with shocks timed to descending phase of a right ventricular endocardial electrogram

What is ventricular fibrillation undersensing?

Ventricular fibrillation (VF), uninterrupted, is fatal within minutes. Implantable cardioverter defibrillators (ICDs) sense ventricular electrograms (EGMs) during VF and detect the VF rhythm (a sequence of VF sensed events) to deliver a shock to terminate VF and save lives. VF sensing and detection in Medtronic ICDs has been reported to be highly sensitive. However, Castellano et al. reported that Medtronic ICDs have the potential for high levels of undersensing in VF, sufficient to underdetect VF and withhold life-saving therapy. This manuscript reviews the process of EGM sensing and VF detection in ICDs and compares the process of sensing in Medtronic ICDs with the process described in this recent publication.

Elimination of Purkinje Fibers by Electroporation Reduces Ventricular Fibrillation Vulnerability.

BackgroundThe Purkinje network appears to play a pivotal role in the triggering as well as maintenance of ventricular fibrillation. Irreversible electroporation (IRE) using direct current has shown promise as a nonthermal ablation modality in the heart, but its ability to target and ablate the Purkinje tissue is undefined. Our aim was to investigate the potential for selective ablation of Purkinje/fascicular fibers using IRE.Methods and ResultsIn an ex vivo Langendorff model of canine heart (n=8), direct current was delivered in a unipolar manner at various dosages from 750 to 2500 V, in 10 pulses with a 90‐μs duration at a frequency of 1 Hz. The window of ventricular fibrillation vulnerability was assessed before and after delivery of electroporation energy using a shock on T‐wave method. IRE consistently eradicated all Purkinje potentials at voltages between 750 and 2500 V (minimum field strength of 250–833 V/cm). The ventricular electrogram amplitude was only minimally reduced by ablation: 0.6±2.3 mV (P=0.03). In 4 hearts after IRE delivery, ventricular fibrillation could not be reinduced. At baseline, the lower limit of vulnerability to ventricular fibrillation was 1.8±0.4 J, and the upper limit of vulnerability was 19.5±3.0 J. The window of vulnerability was 17.8±2.9 J. Delivery of electroporation energy significantly reduced the window of vulnerability to 5.7±2.9 J (P=0.0003), with a postablation lower limit of vulnerability=7.3±2.63 J, and the upper limit of vulnerability=18.8±5.2 J.ConclusionsOur study highlights that Purkinje tissue can be ablated with IRE without any evidence of underlying myocardial damage.

Effect of Interventricular Electrical Delay on Atrioventricular Optimization for Cardiac Resynchronization Therapy.

Background:Routine atrioventricular optimization (AVO) has not been shown to improve outcomes with cardiac resynchronization therapy (CRT). However, more recently subgroup analyses of multicenter CRT trials have identified electrocardiographic or lead positions associated with benefit from AVO. Therefore, the purpose of this analysis was to evaluate whether interventricular electrical delay modifies the impact of AVO on reverse remodeling with CRT.Methods:This substudy of the SMART-AV trial (SMARTDELAY Determined AV Optimization) included 275 subjects who were randomized to either an electrogram-based AVO (SmartDelay) or nominal atrioventricular delay (120 ms). Interventricular delay was defined as the time between the peaks of the right ventricular (RV) and left ventricular (LV) electrograms (RV-LV duration). CRT response was defined prospectively as a >15% reduction in LV end-systolic volume from implant to 6 months.Results:The cohort was 68% men, with a mean age of 65±11 years and LV ejection fraction of 28±8%. Longer RV-LV durations were significantly associated with CRT response (P<0.01) for the entire cohort. Moreover, the benefit of AVO increased as RV-LV duration prolonged. At the longest quartile, there was a 4.26× greater odds of a remodeling response compared with nominal atrioventricular delays (P=0.010).Conclusions:Baseline interventricular delay predicted CRT response. At long RV-LV durations, AVO can increase the likelihood of reverse remodeling with CRT. AVO and LV lead location optimized to maximize interventricular delay may work synergistically to increase CRT response.Clinical Trial Registration:URL: https://www.clinicaltrials.gov. Unique identifier: NCT00874445.

Percutaneousepicardial pacing using a novel transverse sinus device.

Transvenous lead implantation has multiple drawbacks and complications that can be overcome by epicardial lead placement. We aimed to design percutaneously implanted epicardial leads that are anchored through the transverse sinus (TS). We designed a novel multielectrode pacing device with four bipole electrode pairs. The device is advanced through the TS, with both ends externalized out of the pericardium. We tested the prototype in one proof-of-concept and 5 additional acute canine experiments. The TS device recorded ventricular and atrial electrograms. The median amplitude of near-field ventricular electrograms was 3.3mA (IQR 2.0-4.3) and of near-field atrial electrograms was 2.1mA (IQR 1.3-2.2). The median ventricular threshold (N=30) was 1.1mA (IQR 0.7-3.1) at a median pulse width of 0.5ms (IQR 0.5-0.5). The median atrial threshold (N=10) was 2.4mA (IQR 1.1-7.8) at a median pulse width of 0.5ms (IQR 0.5-0.9). Right and left ventricular and atrial pacing morphologies were noted while pacing electrodes adjacent to these chambers. Simultaneous left (LV) and right ventricular (RV) pacing showed reduction in QRS duration from 116ms (RV) and 105ms (LV) to 91ms. On necropsy, the device was located in the TS in all animals. There were TS abrasions in one animal, and no other acute complications. This study highlights a novel approach to epicardial pacing harnessing the unique anatomy of the transverse sinus as an anchoring point. Placement of this novel transverse sinus device was safe and feasible, with acceptable atrial and ventricular thresholds.

Early Diagnosis of Defibrillation LeadDislodgement.

This study sought to develop and evaluate an algorithm for early diagnosis of dislodged implantable cardioverter-defibrillator (ICD) leads. Dislodged defibrillation leads may sense atrial and ventricular electrograms (EGMs), triggering shocks in the vulnerable period that induce ventricular fibrillation (VF). We developed a 2-step algorithm by using experimental lead dislodgements (LDs) at ICD implantation and a control dataset of newly implanted, in situ leads. Step 1 consisted of an alert triggered by abrupt decrease in R-wave amplitude and increase in pacing threshold. Step 2 withheld therapy based on ventricular EGM evidence of LD identified from experimental LD behavior. We estimated the algorithm's performance using a registry dataset of 3,624 new implantations and an atrial dislodgement dataset of 14 LDs at the atrium. In the registry dataset, the algorithm identified 20 of 21 radiographic LDs (95%) at a median of 11 days before clinical diagnosis. Step 1 had positive predictive values of 57% for radiographic LD and 77% for surgical revision. The false positive rate was 0.4% after step 1 and≤0.2% after step 2. In the atrial dislodgement dataset, step 1 identified all 14 LDs; step 2 would have prevented inappropriate therapy in all 7 patients with stored EGMs at LD, including 2 patients with fatal, shock-induced VF. An ICD algorithm can facilitate early diagnosis of defibrillation LD. Additional data are needed todetermine the safety of withholding shocks based on EGM evidence of LD.

Non-invasive epicardial and endocardial electrocardiographic imaging for scar-related ventricular tachycardia.

Contact mapping is currently used to guide catheter ablation of scar-related ventricular tachycardia (VT) but usually provides incomplete assessment of 3D re-entry circuits and their arrhythmogenic substrates. This study investigates the feasibility of non-invasive electrocardiographic imaging (ECGi) in mapping scar substrates and re-entry circuits throughout the epicardium and endocardium. Four patients undergoing endocardial and epicardial mapping and ablation of scar-related VT had computed tomography scans and a 120-lead electrocardiograms, which were used to compute patient-specific ventricular epicardial and endocardial unipolar electrograms (CEGMs). Native-rhythm CEGMs were used to identify sites of myocardial scar and signal fractionation. Computed electrograms of induced VT were used to localize re-entrant circuits and exit sites. Results were compared to in vivo contact mapping data and epicardium-based ECGi solutions. During native rhythm, an average of 493 ± 18 CEGMs were analysed on each patient. Identified regions of scar and fractionation comprised, respectively, 25 ± 4% and 2 ± 1% of the ventricular surface area. Using a linear mixed-effects model grouped at the level of an individual patient, CEGM voltage and duration were significantly associated with contact bipolar voltage. During induced VT, the inclusion of endocardial layer in ECGi made it possible to identify two epicardial vs. three endocardial VT exit sites among five reconstructed re-entry circuits. Electrocardiographic imaging may be used to reveal sites of signal fractionation and to map short-lived VT circuits. Its capacity to map throughout epicardial and endocardial layers may improve the delineation of 3D re-entry circuits and their arrhythmogenic substrates.

New Substrate-Guided Method of Predicting Slow Conducting Isthmuses of Ventricular Tachycardia: Preliminary Analysis to the Combined Use of Voltage Limit Adjustment and Fast-Fourier Transform Analysis.

Several conducting channels of ventricular tachycardia (VT) can be identified using voltage limit adjustment (VLA) of substrate mapping. However, the sensitivity or specificity to predict a VT isthmus is not high by using VLA alone. This study aimed to evaluate the efficacy of the combined use of VLA and fast-Fourier transform analysis to predict VT isthmuses. VLA and fast-Fourier transform analyses of local ventricular bipolar electrograms during sinus rhythm were performed in 9 postinfarction patients who underwent catheter ablation for a total of 13 monomorphic VTs. Relatively higher voltage areas on an electroanatomical map were defined as high voltage channels (HVCs), and relatively higher fast-Fourier transform areas were defined as high-frequency channels (HFCs). HVCs were classified into full or partial HVCs (the entire or >30% of HVC can be detectable, respectively). Twelve full HVCs were identified in 7 of 9 patients. HFCs were located on 7 of 12 full HVCs. Five VT isthmuses (71%) were included in the 7 full HVC+/HFC+ sites, whereas no VT isthmus was found in the 5 full HVC+/HFC- sites. HFCs were identical to 9 of 16 partial HVCs. Eight VT isthmuses (89%) were included in the 9 partial HVC+/HFC+ sites, whereas no VT isthmus was found in the 7 partial HVC+/HFC- sites. All HVC+/HFC+ sites predicted VT isthmus with a sensitivity of 100% and a specificity of 80%. Combined use of VLA and fast-Fourier transform analysis may be a useful method to detect VT isthmuses.

Ventricular activation times in rainbow trout and common carp

The specific objective of the present study was to find out the presence or absence of a transmural gradient of ventricular activation times in fish having pyramidal and sac‐like hearts, which in turn have relatively pronounced and negligible amount of the compact type of myocardium, respectively.Experiments were done in rainbow trout (Onchorhynchus mykiss, n=6; body weight 320–510 g) and common carp (Cyprinus carpio, n=6; body weight 900–1300 g) presenting fish species with the pyramidal (pronounced compact layer) and sac‐like (negligible compact layer) heart types. The investigation was carried out in accordance with the Guide for the Care and Use of Laboratory Animals, 8th Edition published by the National Academies Press (US) 2011. Body surface ECG was recorded in the longitudinal body axis lead. Ventricular unipolar electrograms were recorded from the ventricular walls as described earlier (Vaykshnorayte et al., 2011). In each ventricular lead, activation time were determined as instants of dV/dt minimum during QRS complex (Coronel et al., 2006). Data are expressed as medians and interquartile intervals. Statistical analysis was performed with SPSS package (IBM SPSS Statistics 23, SPSS, Inc., Chicago, Illinois, USA).Common carps demonstrated significantly longer QRS complex in comparison with rainbow trout (79 (IQR 72–85); 56 (IQR 48–61), P&lt;0.05), whereas a difference in RR interval was statistically insignificant (1892 (IQR 1609–2074); 1470 (IQR 970–2175), P&gt;0.05). The gross activation sequence in both species was similar and demonstrated a direction from atrioventricular junction to apex and anterior base (apicobasal activation gradient, P &lt;0.005). The transmural activation pattern was also similar in the studied animals with the activation spread direction from endocardium to epicardium in all parts of the myocardium (transmural activation gradient, P &lt;0.005). In this way, It implies that a transmural activation pattern do not have differences in hearts with different spongy/compact percentage of the ventricular wall in these fish species.Support or Funding InformationThis work was supported by the Ural Branch of the Russian Academy of Sciences (AAAA‐A18‐ 118012290365‐2) and the Program for Fundamental Research of RAS (AAAA‐A17‐ 117012310154‐6).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Idiopathic Ventricular Arrhythmias Originating From the Infundibular Muscles: Prevalence, Electrocardiographic and Electrophysiological Characteristics, and Outcome of Catheter Ablation.

This study investigated the prevalence, electrocardiographic and electrophysiological characteristics, and ablation outcome of idiopathic ventricular arrhythmias (VAs) originating from the infundibular muscles (IFMs) in the right ventricle consisting of the parietal band (PB) and septal band (SB). We studied 19 patients with idiopathic VA origins in the PB in 14 and SB in 5 among 294 consecutive patients with VA origins in the right ventricle. PB and SB VAs exhibited left bundle branch block with a left inferior (n=12) or superior (n=2) axis and left (n=4) or right inferior (n=1) axis pattern, respectively. In lead I, all PB VAs exhibited R waves while SB VAs often exhibited S waves. A QS pattern in lead aVR and the presence of a notch in the mid-QRS were common in all IFMs VAs. During IFMs VAs, a far-field ventricular electrogram with an early activation was always recorded in the His bundle region regardless of the location of the VA origins. With 9.2±6.9 radiofrequency applications and a duration of 972±946 seconds, catheter ablation was successful in 15 patients. VAs recurred in 4 during a follow-up period of 43±24 months. A change in the QRS morphology was observed spontaneously in 5 patients, immediately after ablation in 4, and at the time of the VA recurrence in 2. Idiopathic VAs originating from the IFMs are rare (PB>SB). Catheter ablation of these IFMs VAs was challenging, requiring a large amount of the radiofrequency energy delivery for a successful ablation with a relatively high recurrence rate.

Beat-to-beat variations in activation-recovery interval derived from the right ventricular electrogram can monitor arrhythmic risk under anesthetic and awake conditions in the canine chronic atrioventricular block model

In the chronic atrioventricular block (CAVB) dog model, beat-to-beat variation of repolarization in the left ventricle (LV) quantified as short-term variability of the left monophasic action potential duration (STVLVMAPD) increases abruptly upon challenge with a proarrhythmic drug. This increase occurs before the first ectopic beat (EB), specifically in subjects who demonstrate subsequent repetitive torsades de pointes arrhythmias (TdP). The purpose of this study was to demonstrate that STV is feasible to monitor arrhythmic risk through use of the intracardiac electrogram (EGM) derived from the right ventricular (RV) lead from pacemakers or implantable cardioverter-defibrillators. In 30 anaesthetized, inducible (≥3 TdP) CAVB dogs, STV between LV and RV monophasic action potential duration (STVLVMAPD and STVRVMAPD) was compared. In prospectively enrolled CAVB dogs, STV of the activation-recovery interval (ARI) derived from the RV EGM (STVRVARI) was measured before and after a challenge with dofetilide under anesthesia (2a; n = 10) and cisapride under awake conditions (2b; n = 8). Both STVLVMAPD and STVRVMAPD increased before the first EB (1.29 ± 0.58 ms to 3.05 ± 1.70 ms and 1.11 ± 0.53 ms to 2.18 ± 1.43 ms, respectively; P = 0.001). STVRVARI increased from 2.82 ± 0.33 ms to 3.77 ± 0.69 ms (P = .001). Inducible subjects (4/8) showed an increase in STVRVARI from 2.65 ± 0.55 ms to 3.45 ± 0.33 ms (in the first hour; P = .02) and 4.20 ± 1.33 ms (before the first EB; P = .04). Behavior of STV from the RV and LV is comparable. STVRVARI increases significantly before the occurrence of an arrhythmia in awake and anaesthetized conditions. This finding can be integrated into devices to monitor arrhythmic risk.

Mechanism of electrocardiographic T-wave flattening in diabetes mellitus: experimental and simulation study.

In the present study we investigated the contribution of ventricular repolarization time (RT) dispersion (the maximal difference in RT) and RT gradients (the differences in RT in apicobasal, anteroposterior and interventricular directions) to T-wave flattening in a setting of experimental diabetes mellitus. In 9 healthy and 11 diabetic (alloxan model) open-chest rabbits, we measured RT in ventricular epicardial electrograms. To specify the contributions of apicobasal, interventricular and anteroposterior RT gradients and RT dispersion to the body surface potentials we determined T-wave voltage differences between modified upper- and lower-chest precordial leads (T-wave amplitude dispersions, TWAD). Expression of RT gradients and RT dispersion in the correspondent TWAD parameters was studied by computer simulations. Diabetic rabbits demonstrated flattened T-waves in precordial leads associated with increased anteroposterior and decreased apicobasal RT gradients (P<0.05) due to RT prolongation at the apex. For diabetics, simulations predicted the preserved T-vector length and altered sagittal and longitudinal TWAD proven by experimental measurements. T-wave flattening in the diabetic rabbits was not due to changes in RT dispersion, but reflected the redistributed ventricular repolarization pattern with prolonged apical repolarization resulting in increased anteroposterior and decreased apicobasal RT gradients.

Idiopathic Ventricular Arrhythmias Originating From the Parietal Band: Electrocardiographic and Electrophysiological Characteristics and Outcome of Catheter Ablation.

The parietal band is one of the muscle bands in the right ventricle. This study investigated the electrocardiographic and electrophysiological characteristics and ablation outcome of idiopathic ventricular arrhythmias (VAs) originating from the parietal band. We studied 14 patients with idiopathic VA origins in the parietal band among 294 consecutive patients with VA origins in the right ventricle. The QRS morphologies of the parietal band VAs were characterized by a left bundle branch block and left inferior (n=12) or superior (n=2) axis pattern with the presence of a notch in the middle of the QRS in all cases, precordial transition at ≤lead V3 in 7 patients, and a slow QRS onset in 4 patients. During parietal band VAs, a far-field ventricular electrogram with an early activation was always recorded in the His bundle region, regardless of the location of the VA origins. During the catheter ablation, a mean number of 10.4±7.4 radiofrequency applications with a duration of 1099±1034 seconds were delivered. Catheter ablation was successful in 10 patients, and VAs recurred in 4 during a mean follow-up period of 41±24 months. A change in the QRS morphology was observed spontaneously in 4 patients, immediately after the ablation in 4, and at the time of a VA recurrence in 2. Idiopathic VAs rarely originated from the parietal band. The catheter ablation of the parietal band VAs was always challenging, requiring a large amount of the radiofrequency energy delivery for a successful ablation with a relatively high recurrence rate.

Morphologically constrained signal subspace characterization of electrograms during ventricular fibrillation

Abstract Ventricular fibrillation (VF) is a lethal cardiac arrhythmia traditionally believed to be chaotic in nature. However, recent research studies have shown that certain events of interest during VF may exhibit local (or regional) organization. These time-varying and spatially migrating organized activities manifest themselves into different signal morphologies within electrograms acquired during VF. Performing targeted (or constrained) signal decomposition of electrograms to extract such signal morphologies associated with events of clinical interest will be of significant value. We present one such targeted adaptive signal decomposition of intra-cardiac electrograms during VF, to automatically extract morphologies previously observed in relation to the vicinity of rotor phenomenon (i.e. an event of interest during VF). Using a Gabor dictionary and Matching Pursuits (MP), the proposed method successfully performed targeted signal decomposition in highlighting signal structures that could be used to determine the ventricular electrogram's vicinity to a rotor in the epicardium. A comparative analysis using the MP with a proposed choice function ( P P

Experimental study of cryofreezing energy applications on the ventricular myocardium using sheep hearts.

Cryofreezing energy has been utilized to abolish arrhythmogenic substrates of various kinds of tachyarrhythmias. However, systematic electrophysiological and histological investigations of cryothermia have never been performed. The aim of this study was to clarify those aspects using sheep beating hearts. A total of eight adult sheep were utilized under total anesthesia, and a pericardial cradle was made by opening the pericardium. Eight epicardial plaque electrodes were sutured on the epicardial surface of the left ventricle 2∼3 cm apart from each other. A cryoprobe was inserted through a vent made in the left ventricular apex, and positioned so as to locate the probe tip at a site just opposite the center of the epicardial plaque electrodes. Ventricular electrograms and pacing threshold were measured during endocardial freezing. The volume of the necrotized lesion created by the cryofreezing was measured in the excised hearts after staining. The cryoprobe tip temperature was lowered to -50°C for 10 minutes. A significant increase in the pacing threshold and significant reduction in the ventricular electrograms were observed after endocardial freezing. The transmurality of the necrotized lesions varied depending on the situation of the cryoapplications, and the lesion depth and volume were significantly larger in the transmural lesions; however, there was no significant difference between the transmural and nontransmural lesions regarding the lesion width. Endocardial cryofreezing could provoke significant electrophysiological and injurious effects on the ventricular myocardium in the goat heart. Transmural cryolesions could be created when cryoprobe was appropriately applied.

Recurrence after successful catheter ablation for ventricular arrhythmia from the aortic root

Objective: The mechanism underlying recurrence after successful ablation of ventricular arrhythmias (VAs) was unclear. Spectrum analysis can help to identify near-field activation. The purpose of this study was to quantify the changes of near-field activation in response to ablation at the VAs origin in the aortic root (AR-VAs) and to assess its relationship with late ablation outcome.Methods and results: Patients who underwent acutely successful ablation for AR-VAs were analysed. Ventricular electrograms acquired before and after ablation at VAs origin were subjected to spectrum analysis. The area under the curve of the high frequency component (HFC, 50–200 Hz) and the low frequency component (LFC, 0–50 Hz) was measured. The proportion of HFC to the frequency spectrum of 0–200 Hz was defined as the HFC ratio (HFCR). The reduction of HFC and HFCR in response to ablation was defined as HFC pre–post and HFCR pre–post, respectively. Documentation of VAs with the same morphology after an acute successful procedure was defined as recurrence. Fifty-six patients were analysed, and VAs recurred in 17 patients. HFCR pre–post, HFC pre–post, and HFC pre-ablation were significantly higher in patients without recurrence. And HFCR pre–post has the highest predictive value (area under the receiver-operating characteristic curve: 0.975). A HFCR pre–post of 1.0% differentiated two groups (sensitivity = 84.6%, specificity = 100%). Higher HFCR pre–post was correlated with shorter VAs termination time (correlation coefficient = –0.399, p = .009).Conclusions: HFCR pre–post can quantify the near-field activation change during ablation. Incomplete destruction to the VAs foci could underlie recurrence after successful ablation.

Atrial undersensing secondary to quiet timer blanking in pediatric and congenital heart disease patients.

Atrial undersensing despite normal atrial lead parameters and high amplitude electrograms has been described in adult patients as a consequence of atrial amplifier saturation. Repetitive inputs cause amplifier ringing and undersensing occurs as a consequence of quiet timer blanking. High amplitude ventricular electrograms can also result in atrial blanking secondary to cross-chamber effect. This has not been described in pediatric patients or epicardial pacing systems and specific risk factors are not known. We describe five cases of atrial undersensing in pediatric and congenital heart disease patients with epicardial dual-chamber systems and high ventricular lead outputs. This was a retrospective cohort study of all patients with dual-chamber pacing systems cared for at the Heart Institute at Children's Hospital Colorado. Five cases of atrial undersensing with normal atrial lead parameters were found. All were epicardial systems with acceptable lead parameters at implantation and Medtronic (Medtronic, Inc., Minneapolis, MN, USA) generators with unipolar leads. Ventricular pacing outputs were elevated at presentation, median 5.5 V (5-7.5). Presenting symptoms were exercise intolerance (four) and detection on routine monitoring (one). Successful interventions included reduction in ventricular lead pacing output (one), programming of rate response (two), and implantation of an alternative generator manufacturer (two). Atrial undersensing secondary to amplifier ringing and quiet timer blanking is an uncommon presentation but may be clinically important in patients with unipolar epicardial atrial leads and high pacing outputs from ventricular leads.

Diagnostic Perturbations.

Diagnostic Perturbations.

Usefulness of Intracardiac Local Ventricular Electrogram to Predict Responders in Patients Undergoing Cardiac Resynchronization Therapy

Usefulness of Intracardiac Local Ventricular Electrogram to Predict Responders in Patients Undergoing Cardiac Resynchronization Therapy

Accessory pathway location affects brain natriuretic peptide level in patients with Wolff-Parkinson-White syndrome.

The purpose of this study was to investigate the relationship between the accessory pathway location and brain natriuretic peptide (BNP) level in patients with Wolff-Parkinson-White (WPW) syndrome. We divided 102 WPW syndrome patients with normal left ventricular systolic function into four groups: those with manifest right (MR, n = 14), manifest septal (MS, n = 11), manifest left (ML, n = 30), and concealed (C, n = 47) accessory pathways. BNP level and electrophysiological properties, including difference in timing of the ventricular electrogram between the His bundle area and the distal coronary sinus area (His-CS delay), which indicate intraventricular dyssynchrony, were compared. BNP levels (pg/dl) were higher in the MR and MS groups than in the ML and C groups (MR, 64 ± 58; MS, 55 ± 45; ML, 17 ± 15; C, 25 ± 21; P < 0.001). AV intervals (ms) were shorter in the MR and MS groups than in the ML and C groups (MR, 76 ± 16; MS, 83 ± 6; ML, 101 ± 19; C, 136 ± 20; P < 0.001). His-CS delay (ms) was longer in the MR group than in the other groups (MR, 50 ± 15; MS, 21 ± 7; ML, 23 ± 10; C, 19 ± 8; P < 0.001). The AV interval (P < 0.01) and the His-CS delay (P < 0.001) were negatively and positively correlated, respectively, with the BNP level. Anterograde conduction with a right or septal accessory pathway increased the BNP level in WPW syndrome patients with normal cardiac function.