Comparison of the electrophysiological properties of the pulmonary veins between paroxysmal and persistent atrial fibrillation

Background

The role of the pulmonary veins (PVs) as triggers in atrial fibrillation (AF) is well-known; however, their detailed electrophysiological properties have not been thoroughly examined.

Objective

This study aimed to investigate the electrophysiological properties of the PVs between paroxysmal AF (pAF) and persistent AF (perAF).

Methods

Prior to catheter ablation in patients with pAF (n = 51) and perAF (n = 41), a voltage map of the left atrium and PVs was created under sinus rhythm, and the area of the myocardial sleeves in the PVs and their electrophysiological characteristics, including the pacing threshold and effective refractory period (ERP), were compared between the two groups.

Results

Compared with perAF, the myocardial sleeves of PVs for pAF were significantly larger for all PVs. The ERP for perAF was significantly shorter than that for pAF for all PVs. The pacing threshold for perAF was significantly higher than that for pAF for the right and left superior PVs.

Conclusion

In patients with perAF, a decrease in the normal myocardial sleeves and a shortening of the ERP were observed for all PVs. Those changes in the electrophysiological properties of the PVs might be related to the persistence of AF.

Recent Advances and Future Directions in Syncope Management: A Comprehensive Narrative Review

Syncope is a highly prevalent clinical condition characterized by a rapid, complete, and brief loss of consciousness, followed by full recovery caused by cerebral hypoperfusion. This symptom carries significance, as its potential underlying causes may involve the heart, blood pressure, or brain, leading to a spectrum of consequences, from sudden death to compromised quality of life. Various factors contribute to syncope, and adhering to a precise diagnostic pathway can enhance diagnostic accuracy and treatment effectiveness. A standardized initial assessment, risk stratification, and appropriate test identification facilitate determining the underlying cause in the majority of cases. New technologies, including artificial intelligence and smart devices, may have the potential to reshape syncope management into a proactive, personalized, and data-centric model, ultimately enhancing patient outcomes and quality of life. This review addresses key aspects of syncope management, including pathogenesis, current diagnostic testing options, treatments, and considerations in the geriatric population.

Myelin abnormalities in merosin-deficient congenital muscular dystrophy

INTRODUCTION/AIMS

Merosin is a protein complex located in the basement membrane of skeletal muscles and laminin α2-containing regions of the central and peripheral nervous systems. However, because of the prominence of muscle-related symptoms, peripheral neuropathy associated with merosin-deficient congenital muscular dystrophy type 1A (MDC1A) has received little clinical attention. This study aimed to present pathological changes in intramuscular nerves of three patients with MDC1A and discuss their relationship with electrophysiological findings to provide new evidence of peripheral nerve involvement in MDC1A.

METHODS

MDC1A was confirmed by clinical features, muscle biopsy, and genetic testing for variants in LAMA2. To clarify peripheral nerve involvement, we statistically evaluated electrophysiological and muscle pathology findings of intramuscular nerves. These findings were compared with those of age-matched boys with Duchenne muscular dystrophy (DMD) as controls with normal nerves. Nerve conduction studies (NCS) were performed before biopsy. Biopsied intramuscular nerves were examined with electron microscopy using g-ratio, which is the ratio of axon diameter to myelinated fiber diameter.

RESULTS

The myelin sheaths were significantly thinner in MDC1A patients than in age-matched DMD patients, with a mean g-ratio of 0.76 ± 0.07 in MDC1A patients and 0.65 ± 0.14 in DMD patients (p < .0001). No neuropathic changes were identified in muscle pathology. Low compound muscle action potential amplitudes, positive sharp waves and fibrillation potentials, and low-amplitude motor unit potentials with increased polyphasia indicated myopathic changes; no neurogenic changes were seen.

DISCUSSION

We postulate that the thin myelin associated with MDC1A reflects the role of merosin in myelin maturation.

Electrophysiological and Histopathological Characteristics of Ventricular Tachycardia Associated With Primary Cardiac Tumors

BACKGROUND

Ventricular tachycardia (VT) associated with primary cardiac tumors (PCTs) originating from the ventricles is rare, but lethal, in young patients.

OBJECTIVES

This study aimed to clarify the mechanisms underlying primary cardiac tumor-related ventricular tachycardia (PCT-VT) and establish a therapeutic strategy for this form of VT.

METHODS

Among 67 patients who underwent surgery for VT at our institute between 1981 and 2020, 4 patients aged 1 to 34 years, including 3 males, showed PCT-VT (fibroma, 2; lipoma, 1; and hamartoma, 1), which was investigated using a combination of intraoperative electroanatomical mapping and histopathological studies.

RESULTS

All 4 patients developed electrical storms of sustained VTs refractory to multiple drugs and repetitive endocardial ablations. The VT mechanism was re-entry, and intraoperative electroanatomical mapping showed a centrifugal activation pattern originating from the border between the tumor and healthy myocardium, where fractionated potentials were detected during sinus rhythm. Histopathological studies of serial sections of specimens acquired from these areas revealed tumor infiltration into the surrounding myocardium with cell disorganization, exhibiting myocardial disarray. Several myocardia entrapped in the tumor edges contributed to the development and sustainment of re-entrant VT activation. In the 2 patients in whom complete resection was unfeasible, encircling cryoablation to entirely isolate the unresectable tumor was effective in suppressing VT occurrence.

CONCLUSIONS

The mechanism underlying PCT-VT involves re-entry localized at the tumor edges. Myocardial disarray associated with tumor infiltration is a substrate for this form of VT. Cryoablation along the border between the tumor and myocardium is a promising therapeutic option for unresectable PCT-VT.

Sudden Onset of Broad Complex Tachycardia in a Fit Young Man: A Case Report

Wolff-Parkinson-White (WPW) syndrome is a clinical pre-excitation syndrome often strongly associated with tachyarrhythmias that are predominantly atrioventricular re-entrant tachycardia (AVRT). It is generally considered to be a relatively benign arrhythmogenic condition associated with a slightly higher risk of sudden cardiac death (SCD) in comparison to the general population. Epidemiological data suggests that 0.1%-0.3% of the general population have electrocardiographic (ECG) findings suggesting that during sinus rhythm, in addition to atrioventricular (AV) conduction over the AV node-His bundle pathway, there is an additional atrioventricular conduction across an accessory pathway. Whilst in most cases, such phenomenon is associated with WPW syndrome, other similar conditions, including Lown-Ganong-Levine (LGL) syndrome and Mahaim-type pre-excitation, have also been documented. Our patient is a young man in his late twenties admitted with broad complex tachycardia at 252 beats per minute associated with diaphoresis and pre-syncope. In our case report, we describe how we managed this emergency, eventually unveiling the underlying aetiology as well as a stepwise approach to dealing with adult broad-complex tachycardia.

Catheter-induced right bundle branch block: Practical implications for the cardiac electrophysiologist

The right bundle branch (RBB), due to its endocardial course, is susceptible to traumatic block caused by "bumping" during right-heart catheterization. In the era of cardiac electrophysiology, catheter-induced RBB block (CI-RBBB) has become a common phenomenon observed during electrophysiological studies and catheter ablation procedures. While typically transient, it may persist for the entire procedure time. Compared to pre-existing RBBB, the transient nature of CI-RBBB allows for comparative analysis relative to the baseline rhythm. Furthermore, unlike functional RBBB, it occurs at similar heart rates, making the comparison of conduction intervals more reliable. While CI-RBBB can provide valuable diagnostic information in various conditions, it is often overlooked by cardiac electrophysiologists. Though it is usually a benign and self-limiting conduction defect, it may occasionally lead to diagnostic difficulties, pitfalls, or undesired consequences. Avoidance of CI-RBBB is advised in the presence of baseline complete left bundle branch block and when approaching arrhythmic substrates linked to the right His-Purkinje-System, such as fasciculo-ventricular pathways, bundle branch reentry, and right-Purkinje focal ventricular arrhythmias. This article aims to provide a comprehensive practical review of the electrophysiological phenomena related to CI-RBBB and its impact on the intrinsic conduction system and various arrhythmic substrates.

Electrophysiological study prior to planned pulmonary valve replacement in patients with repaired tetralogy of Fallot

AIM

Ventricular arrhythmias (VAs) are the most common cause of death in patients with repaired Tetralogy of Fallot (rTOF). However, risk stratifying remains challenging. We examined outcomes following programmed ventricular stimulation (PVS) with or without subsequent ablation in patients with rTOF planned for pulmonary valve replacement (PVR).

METHODS

We included all consecutive patients with rTOF referred to our institution from 2010 to 2018 aged ≥18 years for PVR. Right ventricular (RV) voltage maps were acquired and PVS was performed from two different sites at baseline, and if non-inducible under isoproterenol. Catheter and/or surgical ablation was performed when patients were inducible or when slow conduction was present in anatomical isthmuses (AIs). Postablation PVS was undertaken to guide implantable cardioverter-defibrillator (ICD) implantation.

RESULTS

Seventy-seven patients (36.2 ± 14.3 years old, 71% male) were included. Eighteen were inducible. In 28 patients (17 inducible, 11 non-inducible but with slow conduction) ablation was performed. Five had catheter ablation, surgical cryoablation in 9, both techniques in 14. ICDs were implanted in five patients. During a follow-up of 74 ± 40 months, no sudden cardiac death occurred. Three patients experienced sustained VAs, all were inducible during the initial EP study. Two of them had an ICD (low ejection fraction for one and important risk factor for arrhythmia for the second). No VAs were reported in the non-inducible group (p < .001).

CONCLUSION

Preoperative EPS can help identifying patients with rTOF at risk for VAs, providing an opportunity for targeted ablation and may improve decision-making regarding ICD implantation.

Systematic Electrophysiological Study Prior to Pulmonary Valve Replacement in Tetralogy of Fallot: A Prospective Multicenter Study

BACKGROUND

Ventricular arrhythmias and sudden death are recognized complications in tetralogy of Fallot. Electrophysiological studies (EPS) before pulmonary valve replacement (PVR), the most common reintervention in tetralogy of Fallot, could potentially inform therapy to improve arrhythmic outcomes.

METHODS

A prospective multicenter study was conducted to systematically assess EPS with programmed ventricular stimulation in patients with tetralogy of Fallot referred for PVR from January 2020 to December 2021. A standardized stimulation protocol was used across all centers.

RESULTS

A total of 120 patients were enrolled, mean age 39.2±14.5 years, 53.3% males. Sustained ventricular tachycardia was induced in 27 (22.5%) patients. When identifiable, the critical isthmus most commonly implicated (ie, in 90.0%) was between the ventricular septal defect patch and pulmonary annulus. Factors independently associated with inducible ventricular tachycardia were history of atrial arrhythmia (OR, 8.56 [95% CI, 2.43-34.73]) and pulmonary annulus diameter >26 mm (OR, 5.05 [95% CI, 1.47-21.69]). The EPS led to a substantial change in management in 23 (19.2%) cases: 18 (15.0%) had catheter ablation, 3 (2.5%) surgical cryoablation during PVR, and 9 (7.5%) defibrillator implantation. Repeat EPS 5.1 (4.8-6.2) months after PVR was negative in 8 of 9 (88.9%) patients. No patient experienced a sustained ventricular arrhythmia during 13 (6.1-20.1) months of follow-up.

CONCLUSIONS

Systematically performing programmed ventricular stimulation in patients with tetralogy of Fallot referred for PVR yields a high rate of inducible ventricular tachycardia and carries the potential to alter management. It remains to be determined whether a standardized treatment approach based on the results of EPS will translate into improved outcomes.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT04205461.

Dependence of the Atrioventricular Conduction Time on the Conduction through the Atrioventricular Node and His-Purkinje System

The electrical depolarization of the heart passes through various structures of the cardiac conduction system, which modify its conduction to different extents. In this study, we investigated the relationship between the atrioventricular conduction time (AV interval) and its contributors, the atrioventricular node (AVN) and the His-Purkinje system (HPS), as represented by the AH and HV intervals, respectively. We also compared sex differences in these intervals and their relations. Resting intracardiac tracings lasting 5 min were obtained from 64 patients (33 women) during an invasive electrophysiological study. The aforementioned intervals were measured for all consecutive beats. The mean AH interval was 85.9 ms, HV 43.7 ms, and AV 129.6 ms. Men had longer AH (80.0 vs. 65.9 ms), HV (38.4 vs. 35.3 ms), and AV intervals (124.7 vs. 108.5 ms) than women. The AV intervals were linearly correlated with AH intervals in all patients (r² = 0.65). No significant correlation was found between AV and HV intervals in all patients (r² = 0.05). There were no sex differences in these associations. Our results suggest that the atrioventricular conduction time depends mainly on the conduction through the AVN and less on the HPS. These relations are similar in both sexes, although men had longer conduction times through the AVN, HPS, and total atrioventricular conduction time.

Electrocardiographic and electrophysiological characteristics of fasciculoventricular fibers in children

OBJECTIVES

Fasciculoventricular fiber (FVF) that does not cause tachyarrhythmia is a rare form of ventricular preexcitation, which is important to distinguish from Kent fibers. Although adenosine and some electrocardiographic features are important in the differentiation of Wolff Parkinson White (WPW) than FVF, a clear distinction may not always be possible without an electrophysiological study (EPS). In this study, we aimed to present the clinical and electrophysiological features of our pediatric patients with fasciculoventricular fiber.

PATIENTS AND METHOD

Between October 2013 and September 2021, 565 patients who underwent electrophysiological studies due to ventricular preexcitation in our clinic were screened in the study, and 27 (4.7%) patients with fasciculoventricular fiber were included. The data of the patients were obtained from the file records using the electronic internet database system Filemaker®. Electrophysiological study age, weight, gender, symptom, and presence of congenital heart disease of the patients were obtained from the file records. Accessory pathway localization was evaluated according to the modified Arruda algorithm in pre-procedural electrocardiography. In addition, delta wave amplitudes were measured in the first 40 ms from the surface ECG. PR interval, QRS interval, and delta wave amplitude were recorded before and after ablation in patients with additional accessory pathways. Post-procedure values were included in the FVF group.

RESULTS

The mean age of the patients was 11.47±4.25 years. 70.4% of the reasons for admission were symptoms such as palpitations and syncope. Two patients had hypertrophic cardiomyopathy and one patient had ccTGA. In the electrophysiological study, additional manifest WPW was found in 9 (33%) patients (3 patients with high risk, 6 patients with orthodromic supraventricular tachycardia), focal atrial tachycardia in a patient, and atrioventricular nodal reentry tachycardia in a patient. While the delta wave amplitude was found to be 2.56±1.38(1-5.5) mm in the first 40 ms in surface electrocardiography in 9 patients with additional accessory pathway, it was found to be 1.64±0.67(0.5-3) mm in the FVF group. There was no statistically significant difference between the two groups (p = 0.398). Delta wave amplitude >3.5mm was not detected in any patient with isolated FVF. Interestingly, delta wave amplitude was <3.5mm in 7 (78%) of 9 patients who were identified and ablated with an additional accessory pathway. 19 of the patients (59.3%) were adenosine-responsive (18 isolated FVF, 1 manifest AP+FVF adenosine-responsive. 8 patients with other manifest AP + FVF had no pre-procedural adenosine-asystole response, and all of them QRS were expanded).

CONCLUSION

Although the fasciculoventricular fibers themselves are not the cause of tachyarrhythmia, the accessory pathway and other tachyarrhythmia substrate frequency accompanying these cases are quite high (approximately 40%) in EPS. The delta wave characteristics of ablated patients are very similar to FVF patients. While all patients with isolated FVF were adenosine responsive, most of those with additional manifest WPW were unresponsive. Therefore, performing EPS in patients with suspected FVF based on surface ECG features seems to be important for the detection of additional tachyarrhythmias and risky accessory pathways. This article is protected by copyright. All rights reserved.

Inducibility of atrioventricular nodal reentrant tachycardia and ectopic atrial tachycardia in children under general anesthesia

BACKGROUND

In children, invasive electrophysiological studies (EPS) and radiofrequency catheter ablations (RFA) of supraventricular tachycardia (SVT) are often performed under general anesthesia. Atrioventricular nodal reentrant tachycardia (AVNRT) and ectopic atrial tachycardia (EAT) must be inducible during EPS as reliable diagnosis and subsequent therapy are not possible in sinus rhythm. This study aims to assess the problem of noninducible AVNRT and EAT under general anesthesia.

METHODS AND RESULTS

Anesthesia protocols of 166 patients undergoing EPS were retrospectively analyzed. 122 AVNRT patients were compared to 22 whose tachycardia was not inducible but probably due to an AVNRT mechanism. Another 16 patients with inducible EAT were compared to 6 whose EAT appeared on surface ECG but not during EPS. Demographic characteristics were similar among all groups. Inducibility did not differ (p = 0.42) between AVNRT patients with inhalational anesthesia (sevoflurane and/or nitrous oxide) and patients with intravenous anesthesia (propofol with/without remifentanil). The EAT group exhibited lower inducibility under intravenous anesthesia (64%) than under inhalational (88%), however without significance (p = 0.35).

CONCLUSION

Tachycardia induction succeeds with similar frequency under both inhalational and intravenous general anesthesia in children with AVNRT. In children with EAT, inhalational anesthesia is associated with a trend towards better inducibility. This article is protected by copyright. All rights reserved.

Cardiac Rhythm Monitoring Using Wearables for Clinical Guidance before and after Catheter Ablation

Mobile health technologies are gaining importance in clinical decision-making. With the capability to monitor the patient’s heart rhythm, they have the potential to reduce the time to confirm a diagnosis and therefore are useful in patients eligible for screening of atrial fibrillation as well as in patients with symptoms without documented symptom rhythm correlation. Such is crucial to enable an adequate arrhythmia management including the possibility of a catheter ablation. After ablation, wearables can help to search for recurrences, in symptomatic as well as in asymptomatic patients. Furthermore, those devices can be used to search for concomitant arrhythmias and have the potential to help improving the short- and long-term patient management. The type of wearable as well as the adequate technology has to be chosen carefully for every situation and every individual patient, keeping different aspects in mind. This review aims to describe and to elaborate a potential workflow for the role of wearables for cardiac rhythm monitoring regarding detection and management of arrhythmias before and after cardiac electrophysiological procedures.

Sex-Related Differences in Patients With Unexplained Syncope and Bundle Branch Block: Lower Risk of AV Block and Lesser Need for Cardiac Pacing in Women

Objective

To analyze if there are sex-related differences in patients with unexplained syncope and bundle branch block (BBB).

Background

Despite increasing awareness that sex is a major determinant of the incidence, etiology, and the outcomes of different arrhythmias, no studies have examined differences in presentation and outcomes between men and women with syncope and BBB.

Methods

Cohort study of consecutive patients with unexplained syncope and BBB was included from January 2010 to January 2021 with a median follow-up time of 3.4 years [interquartile range (IQR) 1.7–6.0 years]. They were evaluated by a stepwise workup protocol based on electrophysiological study (EPS) and long-term follow-up with an implantable cardiac monitor (ICM).

Results

Of the 443 patients included in the study, 165 (37.2%) were women. Compared with men, women had less diabetes (25.5 vs. 39.9%, p = 0.002) and less history of ischemic heart disease (IHD; 13.3 vs. 25.9%, p = 0.002). Left bundle branch block (LBBB) was more frequent in women (55.2 vs. 27.7%, p < 0.001) while right bundle branch block (RBBB) was more frequent in men (41.5 vs. 67.7%, p < 0.001). His to ventricle (HV) interval in the EPS was shorter in women (58 ms [IQR 52–71] vs. 60 ms [IQR 52–73], p = 0.035) and less women had an HV interval longer than 70 ms (28.5 vs. 38.1%, p = 0.039), however, EPS and ICM offered a similar diagnostic yield in both sexes (40.6 vs. 48.9% and 48.4% vs. 51.1%, respectively). Women had a lower risk of developing atrioventricular block (AVB) (adjusted odds ratio [OR] 0.44–95% CI 0.26–0.74, p = 0.002) and of requiring permanent pacemaker implantation (adjusted hazard ratio [HR] 0.72–95% CI: 0.52–0.99, p = 0.046). The mortality rate was lower in women (4.5 per 100 person-years [95% CI 3.1–6.4 per 100 person-years] vs. 7.3 per 100 person-years [95% CI 5.9–9.1 per 100 person-years]).

Conclusions

Compared to men, women with unexplained syncope and BBB have a lower risk of AVB and of requiring cardiac pacing. A stepwise diagnostic approach has a similar diagnostic yield in both sexes, and it seems appropriate to guide the treatment and avoid unnecessary pacemaker implantation, especially in women.

Electrophysiological Study Prognostic Value and Long-Term Outcome in Drug-Induced Type 1 Brugada Syndrome: The IBRYD Study

OBJECTIVES

This study aimed to retrospectively assess long-term outcome and the prognostic role of electrophysiological study (EPS) for risk stratification of drug-induced type 1 Brugada syndrome (BrS) patients.

BACKGROUND

BrS is a hereditary cardiac disease, predisposing to sudden cardiac death. Few real-world data are available on long-term outcomes of drug-induced type 1 BrS patients, and questions about risk stratification still remain unanswered.

METHODS

The IBRYD (Italian Brugada Syndrome) study is a multicenter observational retrospective study. A total of 226 drug-induced type 1 BrS patients were enrolled from 9 Italian tertiary referral institutions. Primary endpoint was a composite of appropriate implantable cardioverter-defibrillator (ICD) therapy and sudden cardiac death. The authors further assessed clinical predictors to ICD implantation, as well as for arrhythmia induction at EPS, along with EPS as potential risk factor for the outcomes of interest.

RESULTS

142 patients (62.8%) received an ICD due to syncope and/or inducible ventricular tachyarrhythmias at EPS. During a median follow-up of 106 months, 11 patients (4.9%) experienced primary outcome events. The ICD therapy median annual incidence over 8 years was 0.38% (interquartile range: 0% to 1.47%). Ventricular tachyarrhythmia inducibility during EPS was not predictive of arrhythmic events in ICD recipients versus non-ICD patients and in symptomatic versus asymptomatic subgroups, showing a low positive predictive value (9.6% and 8.9%, respectively) versus a high negative predictive value (96.6% and 95%, respectively). The authors reported 29 ICD-related complications and 4.9% inappropriate shocks.

CONCLUSIONS

Drug-induced type 1 BrS patients have a very low arrhythmic risk. Clinical decision for implantation is supported by syncope and/or EPS positivity, though they fail to stratify high-risk patients. A better risk-to-benefit ratio should be pursued, considering both arrhythmic risk and ICD-related complications.

Atrial electrophysiological characteristics of aging

INTRODUCTION

Advancing age is a known risk factor for developing atrial fibrillation (AF), yet it is unknown which electrophysiological changes contribute to this increased susceptibility. The goal of this study is to investigate conduction disturbances and unipolar voltages (UV) related to aging.

METHODS

We included 216 patients (182 male, age: 36-83 years) without a history of AF undergoing elective coronary artery bypass surgery. Five seconds of sinus rhythm were recorded intraoperatively at the right atrium (RA), Bachmann's bundle (BB), the left atrium and the pulmonary vein area (PVA). Conduction delay (CD), -block (CB), -velocity (CV), length of longest CB lines and UV were assessed in all regions.

RESULTS

With aging, increasing conduction disturbances were found, particularly at RA and BB (RA: longest CB line r_s  = .158, p = .021; BB: CB prevalence r_s  = .206, p = .003; CV r_s  = -.239, p < .0005). Prevalence of low UV areas (UV <5th percentile) increased with aging at the BB and PVA (BB: r_s  = .237, p < .0005 and PVA: r_s  = .228, p = .001).

CONCLUSIONS

Aging is accompanied by an increase in conduction disturbances during sinus rhythm and a higher prevalence of low UV areas, particularly at BB and in the RA. These electrophysiological alterations could in part explain the increasing susceptibility to AF development associated with aging.

Supraventricular Tachycardia and Postural Orthostatic Tachycardia Syndrome Overlap: A Retrospective Study

Postural orthostatic tachycardia syndrome (POTS) and supraventricular tachycardia (SVT) are disease states with distinctive features but overlapping clinical manifestations. Currently, studies on the presence of underlying SVT in patients with POTS are lacking. This retrospective study analyzed 64 patients [mean age: 43 years; 41 (61%) women] who had a POTS diagnosis and were found to have concomitant SVT during rhythm monitoring from September 1, 2013 to September 30, 2019 at our Syncope and Autonomic Disorders Clinic. The outcomes assessed were changes in disease severity, frequency of symptoms, heart rate, and blood pressure between before and after SVT ablation. The most frequent types of SVT noted on the electrophysiologic study were atrioventricular nodal reentrant tachycardia (57.81%), atrial flutter (29.68%), atrioventricular reentrant tachycardia (9.37%), atrial tachycardia (1.56%), and junctional tachycardia (1.56%). After SVT ablation, all 64 patients experienced an improvement in symptoms. Palpitations and lightheadedness experienced the most improvement after the procedure (72% vs. 31%; p < 0.001 and 63% vs. 22%; p < 0.001, respectively). There was a significant improvement in the resting heart rate (81.1 ± 12.8 vs. 75.8 ± 15.6 bpm; p < 0.002), but the orthostatic tachycardia on standing persisted (93.6 ± 16.5 vs. 77.3 ± 19.8 bpm; p = 0.14). Underlying SVT in patients with POTS can be missed easily. A strong suspicion and long-term ambulatory cardiac rhythm monitoring can help in diagnosing the condition.

Peripheral nerve hyperexcitability syndrome: A clinical, electrophysiological, and immunological study

INTRODUCTION

Peripheral nerve hyperexcitability syndrome (PNHS) is characterized by muscle fasciculations and spasms. Nerve hyperexcitability and after-discharges can be observed in electrophysiological studies. Autoimmune mechanisms play a major role in the pathophysiology of primary PNHS.

METHODS

We retrospectively conducted a case-control study recruiting patients with clinical and electrophysiological features of PNHS. Control patients were diagnosed with other neuronal or muscular diseases. Contactin-associated protein2 (CASPR2) and leucine-rich glioma-inactivated1 (LGI1) antibodies were examined.

RESULTS

A total of 19 primary PNHS patients and 39 control patients were analyzed. The most common symptoms for the case group were fasciculations (11/19) and muscle spasms (13/19). Case group patients were likely to demonstrate electrodiagnostic findings of nerve hyperexcitability (17/19) and after-discharges in the tibial nerve (19/19). We found high prevalence of CASPR2 (9/19) and LGI1 (6/19) antibodies in the case group.

DISCUSSION

Primary PNHS patients were likely to show after-discharges in the tibial nerve. The pathogenesis of PNHS is autoimmune CASPR2 and LGI1 antibodies are possible pathogenic antibodies for primary PNHS.

Atrial conduction explains the occurrence of the P-wave dispersion phenomenon, but weakly

BACKGROUND

P-wave dispersion (PWD) is believed to be caused by inhomogeneous atrial conduction. This statement, however, is based on limited little solid evidence. The aim of this study was to determine the relationship between atrial conduction and PWD by means of invasive electrophysiological studies.

METHODS

Cross-sectional study in 153 patients with accessory pathways and atrioventricular node reentry tachycardia (AVNRT) undergoing an electrophysiological study. Different atrial conduction times were measured and correlated with PWD.

RESULTS

Only the interatrial (P-DCS) and left intra-atrial conduction times (ΔDCS-PCS) showed a significant correlation with PWD, but this correlation was weak. Multivariate linear regression analysis determined that both P-DCS (β = 0.242; P = .008) and ΔDCS-PCS (β = 0.295; P < .001) are independent predictors of PWD. Performing the multivariate analysis for arrhythmic substrates, it is observed that only ΔDCS-PCS continued to be an independent predictor of PWD. Analysis of the receiver operating characteristic curves showed that regardless of the types of arrhythmic substrates, PWD discriminates significantly, but moderately, to patients with P-DCS and ΔDCS-PCS ≥75 percentile.

CONCLUSIONS

Interatrial and intraleft atrial conduction times were directly and significantly correlated with PWD, but only weakly, and were independent predictors of PWD. In general, PWD correctly discriminates patients with high values in interatrial and intraleft atrial conduction times, but moderately. This is maintained in cases with accessory pathways; however, in patients with AVNRT it only does so for intraleft atrial conduction times. Interatrial and intraleft atrial conduction times weakly explains PWD.

Confirmed cases of Neuroborreliosis with involvement of peripheral nervous system: Description of a cohort

The manifestations of borreliosis in the peripheral nervous system (PNS) remain poorly described. As the symptoms of neuroborreliosis can be reversed with timely introduction of antibiotics, early identification could avoid unnecessary axonal loss. Our aim was to describe the characteristics of confirmed neuroborreliosis cases involving the PNS diagnosed between 2007 and 2017 in our neuromuscular disease center in a nonendemic area (La Pitié-Salpêtrière Hospital, Paris, France).Neuroborreliosis was defined as follows: compatible neurological symptoms without other cause of neuropathy; cerebrospinal fluid and serum analysis (positive serological tests with ELISA, confirmed by Western Blot); and improvement of symptoms with adapted antibiotherapy. All the patients consulting in our center between 2007 and 2017 underwent electrophysiological study.Sixteen confirmed cases of neuroborreliosis involving the PNS were included: 10 cases of meningoradiculoneuritis, 4 of axonal neuropathy, and 2 of demyelinating neuropathy (one acute and one chronic). Only 4 (25%) patients reported tick bites. Meningoradiculoneuritis was characterized by lymphocytic meningitis, intense pain, cranial nerve palsy, and contrast enhancement of nerve roots on imagery. The patients with axonal neuropathy presented sensory symptoms with intense pain but no motor deficit and meningitis was rare. Nerve biopsy of 1 patient revealed lymphocytic vasculitis. Electrophysiological testing showed sensory or sensorimotor axonal neuropathy (3 subacute and 1 chronic) of the lower limbs, with asymmetrical neuropathy in 1 patients, symmetrical neuropathy in one and monomelic sensory mononeuritis multiplex in another. We also found 1 case of acute demyelinating neuropathy, treated with antibiotherapy and immunoglobulins, and 1 chronic demyelinating neuropathy. Overall, diaphragmatic paralysis was frequent (18.6%). Antibiotherapy (mostly ceftriaxone 3-4 weeks) resulted in symptom resolution.This series gives an updated overview of the peripheral complications of neuroborreliosis to help identify this disease so that timely treatment could avoid axonal loss.

Radiofrequency catheter ablation for supraventricular tachycardia in a paediatric population: characteristics of tachycardia mechanisms in a subpopulation with early onset

BACKGROUND

In children, the first episode of supraventricular tachycardia occurs at various ages. The aim of this study is to describe age-specific tachycardia mechanisms, clinical findings, and outcome in a contemporary cohort of paediatric patients with supraventricular tachycardia.

METHODS

Retrospective analysis of 531 consecutive patients with structurally normal hearts under the age of 18 years who underwent invasive electrophysiological study for supraventricular tachycardia. The study population was divided into two groups, early-onset group (n = 57) and late-onset group (n = 474), according to the age of the occurrence of the first tachycardia before or after the age of 12 months.

RESULTS

Accessory pathway-mediated tachycardia was more common (82.5 versus 50.1%, p < 0.001) and the proportion of left-sided accessory pathways was more pronounced (74.5 versus 53.7%, p = 0.01) in the early-onset group than in the late-onset group. The antegrade and retrograde refractory periods of the accessory pathways were similar in both groups, but pre-excitation was more common in the early-onset group (50.9 versus 31.9%, p = 0.007). Typical atrioventricular nodal re-entrant tachycardia was more common (36.7 versus 7.0%, p < 0.001) in the late-onset group. There was no difference among the two groups regarding overall outcome.

CONCLUSION

Accessory pathway-mediated re-entrant tachycardia is the most common mechanism of recurrent supraventricular tachycardia in infants with structurally normal hearts who are later referred to an electrophysiological study. These pathways often cause pre-excitation and tend to be located on the left side whereas their refractory period is not different from that of patients with late-onset tachycardia.

Clinical presentation of paroxysmal supraventricular tachycardia: evaluation of usual and unusual symptoms

Objective

Clinical presentation of paroxysmal supraventricular tachycardia may vary from asymptomatic occurrence or mild perception of palpitation to severe chest pain or syncope. This variation is the most challenging issue in the diagnostic evaluation of rhythm disturbances and paroxysmal supraventricular tachycardia as well. This study sought to evaluate the symptoms during the tachycardia attack or index event in patients who underwent electrophysiological study and ablation procedure.

Methods

This retrospective study included 100 consecutive patients who underwent electrophysiological study and ablation procedures due to supraventricular tachycardia. Structural heart disease, moderate/severe valvular pathology, systemic pathologies, such as connective tissue disease and chronic obstructive lung disease, history of pacemaker implantation was defined as exclusion criteria. In addition, medically managed patients and patients with unsuccessful ablation were not included in the study.

Results

Palpitation was the most frequently observed symptom in 84% of patients, followed by chest pain in 47%, dyspnea in 38%, syncope 26%, lightheadedness in 19%, and sweating in 18% of the patients. The most common symptoms after tachycardia event were fatigue and lightheadedness with frequencies of 56% and 55%, respectively. Forty-five percent of the patients reported more than one, unusually frequent urination within the following 1-3 hours after the index event.

Conclusions

Paroxysmal supraventricular tachycardia might manifest itself as gastrointestinal, neurological, psychosomatic symptoms, and unusual complaints in association with or without main symptoms, including palpitation, chest pain, syncope, and dyspnea. Symptoms after tachycardia or index event should be questioned systematically.

State of Fluoroless Procedures in Cardiac Electrophysiology Practice

In the past decade, the use of interventional electrophysiological (EP) procedures for the diagnosis and treatment of cardiac arrhythmias has exponentially increased. These procedures usually require fluoroscopy to guide the advancement and frequent repositioning of intracardiac catheters, resulting in both the patient and the operator being subjected to a considerable degree of radiation exposure. Although shielding options such as lead gowns, glasses, and pull-down shields are useful for protecting the operator, they do not lessen the patient’s level of exposure. Furthermore, the prolonged use of lead gowns can exponentiate the onset of orthopedic problems among operators. Recent advancements in three-dimensional cardiac mapping systems and the use of radiation-free imaging technologies such as magnetic resonance imaging and intracardiac ultrasound allow operators to perform EP procedures with minimal or even no fluoroscopy. In this review, we sought to describe the state of fluoroless procedures in EP practice.

Left Atrial Intramural Hematoma Post-Ablation of Supraventricular Tachycardia: A Rare Complication Treated Successfully

We report successful management of left atrial hematoma after ablation of supraventricular tachycardia. A 43-year-old female patient experienced chest pain immediately after radiofrequency ablation of a symptomatic left posterolateral accessory pathway. Transthoracic echocardiography demonstrated a large mass occupying the left atrium. Computed tomography and transesophageal echocardiography results were consistent with posterolateral intramural hematoma. She became hemodynamically unstable, requiring emergent surgery. The mass resolved completely by 6 weeks. (Level of Difficulty: Beginner.)

Programmed ventricular stimulation in patients with active vs previous arrhythmic myocarditis

INTRODUCTION

No studies so far addressed the role of invasive programmed ventricular stimulation (PVS) in myocarditis patient's arrhythmic risk stratification.

METHODS AND RESULTS

We present a single-center prospective study on 96 consecutive adult patients (44 ± 13 years, 70.1% males) with myocarditis and ventricular arrhythmias (VA) at index hospitalization. Depending on baseline endomyocardial biopsy (EMB) and cardiac magnetic resonance, patients were divided into two groups: active (A) vs nonactive (NA) myocarditis. All of the patients underwent PVS at index hospitalization. Medical treatment and implantable cardioverter-defibrillator (ICD) implantation were clinically-driven. Malignant VA episodes (MVA = ventricular tachycardias [VT], ventricular fibrillation [VF], appropriate ICD therapy) were evaluated at 54 ± 18 months follow-up (FU). Patients who underwent VT ablation or with myocarditis recurrence (n = 9) were excluded. Of 87 patients, 41 (47.2%) were in group A. PVS was positive in 32 cases (36.8%), 16 A vs 16 NA (P = NS), with no associations with VA type at presentation. Before discharge, 55 patients (63.2%) underwent ICD implant. In FU, MVA occurred in 27 patients (31.0%), 13 A vs 14 NA (P = NS), 18 PVS+ vs 9 PVS- (P < .001). The association between PVS result and FU MVA was maximal in group NA (high rule-out performance with negative predictive value = 90.0%, P < .001) and minimal in group A (low rule-in performance with PPV = 43.8%, P = .302). In the whole population, three independent factors for major VA were identified: major arrhythmic onset by sustained VT or VF (HR 2.8, 95% CI, 1.0-7.4, P = .042), presence of fibrosis at EMB (HR 5.8, 95% CI, 1.1-30.0, P = .038), and PVS positivity (HR 4.2, 95% CI, 1.7-10.7, P = .003).

CONCLUSION

In myocarditis patients presenting with VA, PVS is associated with FU MVA in NA patients, but not in A ones. Overall, risk stratification of arrhythmic myocardits is still complex and multifactorial.

Management of Asymptomatic Wolff-Parkinson-White Pattern by Pediatric Electrophysiologists

OBJECTIVE

To determine the present-day approach of pediatric cardiac electrophysiologists to asymptomatic Wolff-Parkinson-White (WPW) pattern and to contrast to both published consensus statements and a similar survey.

STUDY DESIGN

A questionnaire was sent to 266 Pediatric and Congenital Electrophysiology Society physician members in 25 countries; 21 questions from the 2003 survey were repeated, with new questions added regarding risk stratification and decision making.

RESULTS

We received 113 responses from 13 countries, with responders having extensive electrophysiology experience (median 15 years [IQR 8.5-25 years]). Only 12 (11%) believed that intermittent pre-excitation and 37 (33%) that sudden loss of pre-excitation on exercise test were sufficient evidence of accessory pathway safety to avoid an invasive electrophysiology study. Optimal weight for electrophysiology study was 20 kg (IQR 18-22.5 kg), and 61% and 58% would then ablate all right-sided or left-sided accessory pathways, respectively, regardless of electrophysiological properties, whereas only 23% would ablate all septal accessory pathways (P < .001). Compared with 2003, respondents were more likely to consider inducible arrhythmia (77% vs 26%, P < .001) as sufficient indication alone for ablation.

CONCLUSIONS

In the context of recent literature regarding the reliability of risk-stratification tools, most operators are now performing electrophysiology study for asymptomatic Wolff-Parkinson-White regardless of noninvasive findings. Many will then proceed to default ablation of all accessory pathways distant from critical conduction structures.

Rate and Predictors of Permanent Pacemaker Implantation After Transcatheter Aortic Valve Implantation: Current Status

Transcather aortic valve implantation (TAVI) has become a safe and indispensable treatment option for patients with severe symptomatic aortic stenosis who are at high surgical risk. Recently, outcomes after TAVI have improved significantly and TAVI has emerged as a qualified alternative to surgical aortic valve replacement in the treatment of intermediate risk patients and greater adoption of this procedure is to be expected in a wider patients population, including younger patients and low surgical risk patients. However since the aortic valve has close spatial proximity to the conduction system, conduction anomalies are frequently observed in TAVI. In this article, we aim to review the key aspects of pathophysiology, current incidence, predictors and clinical association of conduction anomalies following TAVI.

Therapy Of Cardiac Arrhythmias In Children: An Emerging Role Of Electroanatomical Mapping Systems

INTRODUCTION

Cardiac arrhythmias are challenging diseases in childhood. Most of them in pediatric subjects (90.2%) are atrioventricular reentrant tachycardias and atrioventricular nodal reentrant tachycardias. The standard 12-lead ECG is a highly accurate diagnostic tool but an invasive electrophysiological study is often required. The main concern about this kind of procedures is their invasive nature and the need of radiations, so antiarrhythmic agents are currently the first line therapy. However, they often show side effects and can be insufficient for the rate control.

MATERIALS AND METHODS

We performed a systematic research on Embase and PubMed. We found 563 articles and selected the most representative 50.

DISCUSSION

Management of cardiac arrhythmias could be very difficult in several scenarios, especially in children with body weight <15 kg and age <4 years. In general, pediatric subjects show a cumulative risk of malignancy greater than adults, having greater life expectancy. On this basis the guiding principle during radiation delivery in electrophysiological procedures is "as low as reasonably achievable" (acronym: ALARA). The development of 3-dimensional (3D) electroanatomical mapping systems allowed significant reduction of exposure. The most recently reported experiences demonstrate safety and feasibility of fluoroless ablation in the most common arrhythmias in children, even in challenging conditions.

CONCLUSION

The first reasonable approach in cardiac arrhythmias involving younger patients seems to be pharmacological. However antiarrhythmic drugs pose problems both in terms of side effects and often have poor efficacy. Expertise in electrophysiological techniques is constantly increasing and the development of new technologies allow us to encourage the use of electroanatomical mapping systems in order to reduce the radiation exposure in children undergoing to catheter ablation, especially for accessory pathways.

Effects of atrial electromechanical delay and ventriculoatrial conduction over the atrial functions in patients with frequent extrasystole and preserved ejection fraction

BACKGROUND

The deterioration of left atrial and ventricular functions was demonstrated in patients with frequent ventricular extrasystole (fVES). The exact pathophysiology of left atrial dysfunction in patients with fVES is unclear. Retrograde ventriculoatrial conduction (VAC) often accompanies fVES, which may contribute to atrial dysfunction. We investigated whether atrial electromechanical delay and VAC are related to these atrial functions in patients with frequent right ventricular outflow tract (RVOT) VES and preserved ejection fraction (pEF).

METHODS

This study included 21 patients with pEF (eight males, 48 ± 11 years), who had experienced more than 10 000 RVOT-VES during 24-h Holter monitoring and had undergone electrophysiological study/ablation. The study also included 20 healthy age- and sex-matched control subjects. Transthoracic echocardiography was performed on all of the subjects. Atrial conduction time was obtained by using tissue Doppler imaging. Strain analysis was performed with two-dimensional speckle tracking echocardiography.

RESULTS

The peak atrial longitudinal strain was significantly impaired in patients with fVES (P = 0.01). In addition, although the interatrial and left atrial conduction delay times were significantly different between each group (P < 0.001, P < 0.001), the right atrial conduction delay times were similar. When patients with fVES were divided into groups depending on the existence of retrograde VAC, atrial deformation parameters and conduction delay time did not significantly differ between either group.

CONCLUSION

Frequent RVOT-VES causes left atrial dysfunction. This information is obtained through strain analyses and recordings of left atrial conduction times in patients with pEF. Regardless, retrograde VAC is not related to atrial dysfunction.

Assessment of Peripheral Neuropathy in Patients with β-Thalassemia via Electrophysiological Study: Reevaluation in the Era of Iron Chelators

Peripheral neuropathy is one of the complications of β-thalassemia (β-thal) that has been investigated in limited reports. We aimed to detect the rate of peripheral neuropathy and risk factors for neuropathy development in patients with β-thal. The study was performed in patients with β-thal intermedia (β-TI) or β-thal major (β-TM). Prospective electrophysiological studies were achieved via standard procedures. A total of 27 patients were enrolled in the study. Electrophysiological studies for both motor and sensory nerves were within normal range. In motor nerve studies, delayed peroneal nerve latency was found in patients with high ferritin levels, increased ulnar nerve amplitude was detected in patients ≥20 years old, and increased tibial nerve amplitude was seen in patients with low copper levels. We could not show peripheral neuropathy in our patients. Increased ferritin level, older age, and copper deficiency may cause mild changes in electrophysiological studies of motor nerves.

Alanine-Scanning Mutagenesis of α-Conotoxin GI Reveals the Residues Crucial for Activity at the Muscle Acetylcholine Receptor

Recently, the muscle-type nicotinic acetylcholine receptors (nAChRs) have been pursued as a potential target of several diseases, including myogenic disorders, muscle dystrophies and myasthenia gravis, etc. α-conotoxin GI isolated from Conus geographus selectively and potently inhibited the muscle-type nAChRs which can be developed as a tool to study them. Herein, alanine scanning mutagenesis was used to reveal the structure–activity relationship (SAR) between GI and mouse α1β1δε nAChRs. The Pro⁵, Gly⁸, Arg⁹, and Tyr¹¹ were proved to be the critical residues for receptor inhibiting as the alanine (Ala) replacement led to a significant potency loss on mouse α1β1δε nAChR. On the contrary, substituting Asn⁴, His¹⁰ and Ser¹² with Ala respectively did not affect its activity. Interestingly, the [E1A] GI analogue exhibited a three-fold potency for mouse α1β1δε nAChR, whereas it obviously decreased potency at rat α9α10 nAChR compared to wildtype GI. Molecular dynamic simulations also suggest that loop2 of GI significantly affects the interaction with α1β1δε nAChR, and Tyr¹¹ of GI is a critical residue binding with three hydrophobic amino acids of the δ subunit, including Leu⁹³, Tyr⁹⁵ and Leu¹⁰³. Our research elucidates the interaction of GI and mouse α1β1δε nAChR in detail that will help to develop the novel analogues of GI.

Missed diagnosis of chronic inflammatory demyelinating polyneuropathy in a patient with cervical myelopathy due to ossification of posterior longitudinal ligament

In the current study, we report a missed diagnosis of combined chronic inflammatory demyelinating polyneuropathy (CIDP) in a patient with a cervical spinal cord lesion. At 3.5 months after the onset of symptoms, a 60-year-old female with mild motor weakness and significant weight loss underwent a surgical operation for decompression of the cervical spinal cord. However, her motor weakness was severely aggravated despite the surgical treatment, and she could not walk independently at 10 months after symptom onset. Based on the results of electrophysiological and cerebrospinal fluid tests, we diagnosed her with CIDP. Considering her medical history and the results of our evaluations, we think our patient's neurological symptoms before the surgical operation were attributed, at least in part, to CIDP. Our study shows that clinicians should consider the possibilities of other lesions in different areas even when patients have a definite lesion in the cervical spinal cord or cervical spine.

Gender Differences in Prognosis and Risk Stratification of Brugada Syndrome: A Pooled Analysis of 4,140 Patients From 24 Clinical Trials

Background: Male gender has been consistently shown to be a risk factor for a greater number of arrhythmic events in patients with Brugada Syndrome (BrS). However, there have been no large-scale comprehensive pooled analyses to statistically and systematically verify this association. Therefore, we conducted a pooled analysis on gender differences in prognosis and risk stratification of BrS with a largest sample capacity at present.

Methods: We searched PubMed, Embase, Medline, Cochrane Library databases, Chinese National Knowledge Infrastructure, and Wanfang Data for relevant studies published from 2002 to 2017. The prognosis and risk stratification of BrS and risk factors were then investigated and evaluated according to gender.

Results: Twenty-four eligible studies involving 4,140 patients were included in the analysis. Male patients (78.1%) had a higher risk of arrhythmic events than female patients (95% confidence interval: 1.46–2.91, P < 0.0001). Among the male population, there were statistical differences between symptomatic patients and asymptomatic patients (95% CI: 2.63–7.86, P < 0.00001), but in the female population, no statistical differences were found. In the female subgroup, electrophysiological study (EPS) positive patients had a tendency toward a higher risk of arrhythmic events than EPS-negative patients (95% CI: 0.93–29.77, P = 0.06).

Conclusions: Male patients are at a higher risk of arrhythmic events than female patients. Within the male population, symptomatic patients have a significantly higher risk profile compared to asymptomatic patients, but no such differences are evident within the female population. Consequently, in the female population, the risk of asymptomatic patterns cannot be underestimated.

ELectrophysiological mechanisms underlying the Inhibitory CArdiac syncope without asystolic significant pause: Therapeutic and prognostic implications. The ELICA randomized trial

BACKGROUND

The aim of this study was to investigate syncope recurrence in patients with a 2A cardioinhibitory response to the head up tilt testing (HUT).

METHODS

In this study, we enrolled 72 consecutive patients affected by syncope with cardioinhibitory response without asystolic significant pause to HUT (2A type). In these patients, we randomly performed electrophysiological study (ES). In case of sino-atrial node, atrio-ventricular node dysfunction, and sustained arrhythmias induction, the ES resulted positive. ES was positive in 9 patients (group A), then treated by catheter ablation, and/or by devices implants. Otherwise, ES resulted negative (group B), and these patients did not receive an interventional treatment. However, after ES, we evaluated syncope recurrence during 360 days follow-up.

RESULTS

There was a lower statistical significant syncope recurrence at follow-up, comparing group A to group B of patients [n of events 9 (40.9%) vs 8 (57.1%), P < .05]. At multivariate analysis, ES result was the only factor predicting syncope recurrence at follow-up (hazard ratio = 27.63, 95% confidence interval = 1.02-54.24, P < .005).

CONCLUSION

The positivity to ES study, and successful interventional therapies may reduce the burden of syncope recurrence at 360 days follow-up in 2A HUT subjects.Clinical trial number: NCT02861274.

Evaluation of central and peripheral neuropathy in patients with chronic obstructive pulmonary disease

Background

The aim of the study was to investigate the frequency and characteristics of peripheral nervous system (PNS) and central nervous system (CNS) involvement in COPD.

Methods

The study included 41 COPD patients and 41 healthy volunteers. Electrophysiological studies were carried out: electromyography (EMG) and visual evoked potentials (VEPs). The median nerve, ulnar nerve, common peroneal nerve, and tibial nerve were evaluated for latency, amplitude, and conduction velocity.

Results

The mean age of patients with COPD was 61.8 years and disease duration 10.3 years. There was no difference between patient and control groups in terms of age, BMI, smoking status, or biochemical parameters. Upon VEP examination, latencies were significantly prolonged and amplitudes shortened in the patient group compared to the control group. In EMG measurements, conduction velocity and amplitudes in all nerves were low in the patient group. Similarly, latencies in all nerves were higher in patients with COPD.

Conclusion

Central and peripheral nervous system involvement could develop in patients with moderate-severe COPD, and these patients should be monitored for neuropathic changes in combination with neurological examination.

Low Back Pain in Patients with Lumbar Spinal Stenosis-Hemodynamic and electrophysiological study of the lumbar multifidus muscles

Introduction

Several studies have demonstrated improvement in low back pain (LBP) after decompression surgery for lower extremity symptoms in lumbar spinal stenosis (LSS); however, the influence of neuropathic disorders on LBP is uncertain. Aim of this study is to identify the features of motion-induced and walking-induced LBP in patients with LSS and to assess whether neuropathic LBP develops.

Methods

In total, 234 patients with LSS including L4/5 lesion were asked to identify their LBP. Subjects were classified into three groups: walking-induced LBP that aggravated during walking (W group), motion-induced LBP that aggravated during sitting up (M group), and no LBP (N group). Cross-sectional areas of the dural sac, lumbar multifidus, and the erector spinae were measured. Intramuscular oxygenation was evaluated with near-infrared spectrophotometer. Surface electromyography (EMG) and mechanomyography (MMG) were performed on the lumbar multifidus. Morphological, hemodynamic, and electrophysiological differences in the onset of LBP were evaluated.

Results

The prevalence of W, M, and control groups was 31.2%, 32.1%, 36.8%, respectively. Concordance between the laterality of LBP and leg symptoms including pain and numbness was 86.3% in the W group and 47.0% in the M group. Dural sac area was lower in the W group than in the M and control groups. In the hemodynamic evaluation, the oxygenated hemoglobin level was significantly lower in the W group than in the M and N groups. In electrophysiological evaluation of lumbar multifidus, the mean power frequency in EMG was significantly higher in the W group than in the N group. Amplitude in MMG was significantly lower in the W group than in the N group.

Conclusions

Neurologic disturbance in patients with LSS may be attributed to “neuropathic LBP.” Neuropathic multifidus disorder plays a role in walking-induced LBP.

Initial experience of catheter ablation for cardiac arrhythmias in children and adolescents at a newly built ablation centre

BACKGROUND

Catheter ablation (CA) therapy is the first-choice treatment in adults with heart rhythm disturbances. Arrhythmias in adults are mainly conditioned by coronary artery disease. Aetiology of arrhythmias in children is mostly associated with inherited heart disorders. According to the current guidelines, CA is widely used in children, indicating the need to make it more achievable in the paediatric population.

AIM

To assess the efficacy and safety of CA in children with different types of arrhythmias on the initial learning curve at a newly built Ablation Centre in the Independent Paediatric Hospital of the Medical University of Warsaw, Poland.

METHODS

The study population comprised 32 children with supraventricular tachycardias, asymptomatic pre-excitation syndrome, or ventricular ectopic beats undergoing CA. The mean age of the study population was 14.1 ± 2.4 years. In all patients, electrophysiological study (EPS) and CA were performed. Analysis with respect to procedure duration, fluoroscopy exposure duration, location of accessory pathways (AP), success rate, recurrences, and complications was performed.

RESULTS

The mean procedure duration was 105.4 ± 41.4 min (range 40-175 min). The mean fluoroscopy duration was 8:34 ± 5:01 min (range 1:28-21:01). The mean exposure to ionising radiation was 4.7 ± 3.2 mcG/kg. EPS revealed significantly more frequent presence of AP in the left side (57.1%). The radiofrequency ablation procedure was successful in 26 of 32 (81.3%) children, and cryoablation was successful in two of four patients. In two (6.3%) children minor complications occurred.

CONCLUSIONS

Catheter ablation may be effectively performed without major complications in the initial phase of the learning curve if a reasonable approach with a gradual increase of the procedural complexity is taken.

Electrophysiological Assessment for Splinting in the Treatment of Carpal Tunnel Syndrome

An electrophysiological study is commonly used to decide a therapeutic strategy for carpal tunnel syndrome (CTS). In this study, the electrophysiological parameter measurement as a prognostic indicator for CTS after wrist splinting was assessed to identify appropriate candidates for wrist splinting for CTS. One hundred and six hands in 78 patients with CTS were treated by wrist splinting, and three electrophysiological parameters; median distal motor latency (DML) of the abductor pollicis brevis (APB) muscle, median distal sensory latency (DSL) of the index finger, and second lumbrical-interossei latency difference (2L-INT LD); were statistically analyzed to compare with clinical results by Kelly’s evaluation respectively. Clinical results were excellent in 15 hands, good in 51 hands, fair in 19 hands, and poor in 21 hands. The recordable rate in 2L-INT LD (99.1%) was higher than DML (96.2%) and DSL (79.2%). Patients with DML less than 6.5 ms, DSL less than 5.7 ms, or 2L-INT LD less than 2.5 ms had significantly excellent or good clinical results. The odds ratios of the DML, DSL, and the 2L-INT LD were 7.93, 8.81, and 12.8, respectively. This study demonstrated that CTS patients with DML less than 6.5 ms, DSL less than 5.7 ms, or 2L-INT less than 2.5 ms were good candidates for wrist splinting. Especially, the 2L-INT LD could be the most reliable indicator to predict clinical results for all grades of CTS. This electrophysiological information could be useful in further improvement of accurate diagnosis of CTS, and may help in the assessment of appropriate treatment for CTS with wrist splinting.

Prevalence of Fibromyalgia Syndrome and Its Correlations with Arrhythmia in Patients with Palpitations

OBJECTIVE

It is aimed to determine the prevalence of fibromyalgia syndrome (FMS) and its correlations with arrhythmia in patients with palpitations.

MATERIAL AND METHODS

Sixty-two patients who underwent electrophysiological study (EPS) due to palpitation complaints in Cardiology department and 40 healthy controls were included in the study. The precise diagnosis of arrhythmia was established using EPS. All participants were screened for FMS using American College of Rheumatology 2010 Fibromyalgia diagnostic criteria. Clinical assessments included measurement of severity of pain, fatigue and morning fatigue with visual analog scale (VAS), functional status with Fibromyalgia Impact Questionnaire (FIQ), and anxiety/depression with Hospital Anxiety and Depression Scale (HAD).

RESULTS

FMS was diagnosed in 22 of the 62 patients (36%), and 4 of the 40 healthy controls (10%) (p 0.05). EPS+ patients with FMS had higher fatigue levels, HAD and FIQ scores than EPS- patients, although statistically insignificant. HV durations were statistically longer in the EPS- subgroup (p < 0.05) but other EPS data were similar.

CONCLUSION

FMS frequency and HAD anxiety scores were found to be higher in patients with palpitation complaints. However, we found no association between arrhythmia, EPS parameters and FMS. In our clinical practice we should keep in mind to carry out assessments in terms of FMS in patients with palpitation.

Brugada Syndrome:Risk Stratification And Management

The Brugada syndrome (BrS) is an arrhythmogenic disease associated with an increased risk of ventricular fibrillation and sudden cardiac death. The risk stratification and management of BrS patients, particularly of asymptomatic ones, still remains challenging. A previous history of aborted sudden cardiac death or arrhythmic syncope in the presence of spontaneous type 1 ECG pattern of BrS phenotype appear to be the most reliable predictors of future arrhythmic events. Several other ECG parameters have been proposed for risk stratification. Among these ECG markers, QRS-fragmentation appears very promising. Although the value of electrophysiological study still remains controversial, it appears to add important information on risk stratification, particularly when incorporated in multiparametric scores in combination with other known risk factors. The present review article provides an update on the pathophysiology, risk stratification and management of patients with BrS.

Early onset Charcot-Marie-Tooth neuropathy type 2A and severe developmental delay: expanding the clinical phenotype of MFN2-related neuropathy

Charcot-Marie-Tooth (CMT) syndromes are a group of clinically heterogeneous disorders of the peripheral nervous system. Mutations of mitofusin 2 (MFN2) have been recognized to be associated with CMT type 2A (CMT2A). CMT2A is primarily an axonal disorder resulting in motor and sensory neuropathy. We report a male child with psychomotor delay, dysmorphic features, and weakness of lower limbs associated with electrophysiological features of severe, sensory-motor, axonal neuropathy. The patient was diagnosed with early onset CMT2A and severe psychomotor retardation associated with c.310C>T mutation (p.R104W) in MFN2 gene. CMT2A should be considered in patients with both axonal sensory-motor neuropathy and developmental delay.

Hereditary Neuropathy With Liability to Pressure Palsies: A Single-Center Experience in Southern Brazil

The spectrum of clinical and electrophysiological features in hereditary neuropathy with liability to pressure palsies (HNPP) is broad. We analyze a series of Brazilian patients with HNPP. Correlations between clinical manifestations, laboratory features, electrophysiological analyze, histological and molecular findings were done. In five cases, more than one episode occurred before diagnosis. Median nerve in the carpal tunnel at the wrist, ulnar nerve in its groove at the elbow, fibular nerve in the head of the fibula at the knee, radial nerve in its groove of the humerus and suprascapular nerve in its notch at the supraspinous fossa were found as focal neuropathies. One patient presented with persistent writer's cramp after ulnar nerve palsy. Nerve conduction studies showed focal neuropathy in all patients and concomitant generalized symmetrical neuropathy in eight patients. Molecular analysis of the PMP22 gene detected deletion of the 1.5-Mb fragment in all patients.

Comparison of Edwards Sapien XT versus Lotus Valve Devices in Terms of Electrophysiological Study Parameters in Patients Undergoing TAVI

BACKGROUND

The purpose of this study is to assess the electrocardiographic and electrophysiological parameters of conduction abnormalities in patients undergoing transcatheter aortic valve implantation (TAVI) due to severe aortic valve stenosis.

METHODS

The study included 55 patients who underwent TAVI using either the Boston Scientific Lotus (n:25) (Boston Scientific, Natick, MA, USA) or Edwards Sapien XT (n:30) (Edwards Lifesciences, Irvine, CA, USA) prostheses. An electrophysiological study (EPS) was performed in the catheterization room immediately before the initial balloon valvuloplasty and immediately after prosthesis implantation.

RESULTS

QRS duration and His-bundle to His-ventricle (HV) intervals, which were similar between the two groups before the procedure, were found to be significantly higher in the Lotus valve group postprocedure. Permanent pacemakers (PPMs) were required more frequently in the Lotus group than in the Sapien XT group at discharge (24.0% vs 6.7%, P = 0.07). With the exception of a higher prevalence of paravalvular leakage (P < 0.001) in patients undergoing Sapien XT implantation, other clinical outcomes were similar between the two groups. Multiple regression analysis revealed that baseline atrioventricular (AV) conduction disorders and HV intervals after the procedure were independently associated with PPM implantation after TAVI.

CONCLUSION

In this first study comparing the findings of EPS and electrocardiography, the impact of the Lotus valve on AV conduction systems was greater than that of the Sapien XT. However, the need for PPM was higher in the Lotus valve than in the Sapien XT. PPM requirement is related to valve design; it may decrease with reduced frame height and metal burden in novel valve systems.

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

OBJECTIVES

There are very little data on pre-excitation syndrome (PS) in the elderly. We investigated the influence of advancing age on clinical presentation, treatment and long-term outcome of PS.

SETTING

Single-centre retrospective study of patient files.

PARTICIPANTS

In all, 961 patients (72 patients ≥60 years (mean 68.5±6), 889 patients <60 years (mean 30.5±14)) referred for overt pre-excitation and indication for electrophysiological study (EPS) were followed for 5.3±5 years. Usual care included 24 h Holter monitoring, echocardiography and EPS. Patients underwent accessory pathway (AP) ablation if necessary.

PRIMARY AND SECONDARY OUTCOME MEASURES

Occurrence of atrial fibrillation (AF) or procedure-induced adverse event.

RESULTS

Electrophysiological data and recourse to AP ablation (43% vs 48.5%, p=0.375) did not significantly differ between the groups. Older patients more often had symptomatic forms (81% vs 63%, p=0.003), history of spontaneous AF (8% vs 3%, p=0.01) or adverse presentation (poorly tolerated arrhythmias: 18% vs 7%, p=0.0009). In multivariable analysis, patients ≥60 years had a significantly higher risk of history of AF (OR=4.2, 2.1 to 8.3, p=0.001) and poorly tolerated arrhythmias (OR=3.8, 1.8 to 8.1, p=0.001). Age ≥60 years was associated with an increased major AP ablation complication risk (10% vs 1.9%, p=0.006). During follow-up, occurrence of AF (13.9% vs 3.6%, p<0.001) and incidence of poorly tolerated tachycardia (4.2% vs 0.6%, p=0.001) were more frequent in patients ≥60 years, although frequency of ablation failure or recurrence was similar (20% vs 15.5%, p=0.52). In multivariable analysis, patients ≥60 years had a significantly higher risk of AF (OR=2.9, 1.2 to 6.8, p≤0.01).

CONCLUSIONS

In this retrospective monocentre study, patients ≥60 years referred for PS work up appeared at higher risk of AF and adverse presentation, both prior and after the work up. These results suggest that, in elderly patients, the decision for EPS and AP ablation should be discussed in light of their suspected higher risk of events and ablation complications. However, these findings should be further validated in future prospective multicentre studies.

Neurofibromatosis 2 with peripheral neuropathies: Electrophysiological, pathological and genetic studies of a Taiwanese family

The objective of this study was to assess peripheral nerve involvement and DNA mutation of the neurofibromatosis type 2 (NF2) gene (NF2) in a Taiwanese family with classic NF2. Eleven members (six symptomatic and five asymptomatic) of a family carrying NF2 underwent clinical examination, neuroimaging, and electrophysiological analysis. Mutation and linkage analyses were conducted on DNA samples prepared from peripheral blood (all individuals), a sural nerve biopsy specimen (one symptomatic member), and a tumor specimen (another symptomatic member). Six of the 11 members were diagnosed with classic NF2. DNA sequencing of the tumor specimen demonstrated a frameshift mutation with 756delC on exon 8 of NF2. Three affected subjects showed clinical variability of the neuropathic disorders. Electrophysiological studies demonstrated variation in the disease pattern and severity of peripheral nerve involvement in five affected subjects. The morphometric assessment of the sural nerve biopsy specimen showed a marked reduction in both large myelinated and unmyelinated fibre density and increased density of non-myelinating Schwann cell nuclei. Apart from numerous pathological nuclei of isolated Schwann cells, multiple profiles of non-myelinating Schwann cell subunits were apparent in the endoneurium. Schwann cell proliferation in association with first-hit mutation of the merlin gene might be responsible for the NF2-associated neuropathy. Sural nerve biopsy showed a progressive neuropathy in the disease. Further, we suggest nonmyelinating Schwann cells are involved in NF2 neuropathy.