Electrophysiological Features Of Patients Research Articles

Clinical, Autonomic & Electrophysiological Features in Patients with Guillain Barre Syndrome in a Tertiary Care Hospital of Bangladesh

Background: Guillain-Barre Syndrome (GBS) is the most common cause of acute flaccid paralysis in the adult population. It is an acute post infectious immune mediated peripheral neuropathy with a marked variation in pathology, clinical presentation and prognosis.
 Objective: The aim of the study were to evaluate clinical profile, to assess autonomic involvement & electrophysiological findings in adult patients with GBS.
 Methods: An observational, cross sectional study was carried out in the Department of Neurology, BSMMU, Dhaka from March, 2015 to September, 2017. Total 43 patients of GBS fulfilling the inclusion criteria were recruited as the study population. Detailed clinical examination, CSF study & nerve conduction study were done. Disability status was measured by Hughes functional grading scale. For autonomic assessment 35 adult healthy control were also included for comparison. Then following tests of autonomic nervous system were performed in both patient and control group 1) resting heart rate and heart rate on changing posture (30: 15 ratio) 2) supine blood pressure and blood pressure on changing posture 3) heart rate response to valsalva maneuver 4) heart rate response to deep breathing and E: I ratio 5) sphincter disturbance by symptoms questionnaire.
 Results: The mean age of patients was 35±12 years (range18 to 65 years) with slight male predominance (58.1%). Major clinical presentation was weakness of all 4 limbs followed by sensory complaints (44.2%). 7% of the patient had breathing difficulty and dysphagia. Only 4.7 % had diplopia. Among the symptoms of autonomic dysfunction most common symptoms was constipation (30.2 %) followed by palpitation (14%), urinary retention (7%), lightheadedness and urinary incontinence (4.7%). Cranial nerve palsy was present in 34.9% of cases among them facial palsy was found commonly (27.9%), followed by bulbar palsy (7%) and ophthalmoplegia (4.7%). One patient (2.3%) had both facial palsy and ophthalmoplegia. AIDP, AMAN and AMSAN subtypes comprised 32.6%, 37.2% and 20.9% of cases respectively. Regarding autonomic dysfunction variation of heart rate by different maneuver like posture change, deep breathing and valsalva maneuver was found commonly. 30:15 ratio was abnormal in majority of the patients (82.4%) followed by abnormal max-min HR/min on deep breathing (58.1%) and abnormal valsalva ratio (37.2%). Other abnormalities were postural hypotension (38.2%), sinus tachycardia (25.6%), hypertension (16.3%), hypotension (4.7%), and sinus arrhythmia (4.7%). Bowel bladder dysfunction was another autonomic dysfunction among them constipation 30%, urinary retention 7% and urinary incontinence 4.7% of cases.
 Conclusion: GBS can be presented with variable presentation including autonomic dysfunction. In this study common clinical presentation was limb weakness & different patterns of autonomic dysfunction was found in patients with GBS. Common electrophysiological subtype was AMAN. So in addition to clinical & electrophysiological analysis autonomic evaluation is essential in every patients with GBS as autonomic dysfunction is one of important cause of mortality.
 Bangladesh Journal of Neuroscience 2019; Vol. 35 (2): 57-62

Investigation of the Video-EEG Findings and Clinical Data in Patients Diagnosed With Epilepsy and Psychosis.

Studies on electrophysiological characteristics of patients with epilepsy and concomitant psychosis are limited. We aimed to investigate the clinical and video-electroencephalography (EEG) findings of patients with epilepsy-related psychosis (EP). Fifteen patients diagnosed with EP, assessed at the video-EEG monitoring unit and were under follow-up at both epilepsy and psychiatry clinics, were included. A total of 67 nonpsychotic epilepsy patients, investigated at the video-EEG monitoring unit were randomly selected as the control group and compared statistically with the EP group. In medical history, patients with EP had experienced significantly higher level of status epilepticus (P=0.002) and perinatal cerebral injury (P=0.04), whereas drug-resistant epilepsy was detected at a lower level (P=0.015). With respect to seizure onset zone, the EP group had significantly more seizures of unknown foci, whereas the control group had mostly temporal lobe origin (P=0.0004). EEG findings showed that slow background activity was significantly common among patients with EP (P=0.009). Although only 5 of 15 patients with EP had been operated, 43 of 67 patients had undergone epilepsy surgery (P=0.04) in the control group. However, there was no significant difference between the 2 groups with respect to postoperative seizure control as per Engel classification. Although our sample size could be considered small, slowed EEG background activity, and the marked frequency of initial precipitant factors such as status epilepticus, perinatal cerebral injury, and detected neuronal autoantibodies suggested that EP is associated with more extensive involvement. EP is not a contraindication for epilepsy surgery, when appropriately investigated preoperatively.

Clinical and electrophysiological characteristics of patients with paroxysmal intra-His block with narrow QRS complexes

Atrioventricular (AV) block is usually due to infranodal disease and associated with a wide QRS complex; such patients often progress to complete AV block and pacemaker dependency. Uncommonly, infranodal AV block can occur within the His bundle with a narrow QRS complex. The aims of this study were to define clinical/echocardiographic characteristics of patients with AV block within the His bundle and report progression to pacemaker dependency. We retrospectively identified patients with narrow QRS complexes and documented intra-His delay or block at electrophysiology study (group A) or with electrocardiogram-documented Mobitz II AV block/paroxysmal AV block (group B). Clinical, electrophysiological, and echocardiographic variables at presentation and pacemaker parameters at the last follow-up visit were evaluated. Twenty-seven patients (19 women) were identified (mean age 64 ± 13 years; range, 38-85 years). Four patients who had <1 month of follow-up were excluded. There were 12 patients in group A and 11 in group B; 21 of 23 presented with syncope/presyncope. All patients received pacemakers: 8 single chamber and 15 dual chamber. After a median follow-up of 6.4 years, the median percentage of ventricular pacing was 1% (interquartile range 0%-4.66%). One patient developed true pacemaker dependency. Aortic and/or mitral annular calcification was present in 13 of 22 patients with available echocardiograms. Patients who present with syncope and narrow QRS complexes with intra-His delay or Mobitz II paroxysmal AV block with narrow QRS complexes rarely progress to pacemaker dependency and require infrequent pacing. This entity is more common in women, with a higher prevalence of aortic and/or mitral annular calcification. If confirmed by additional studies, single-chamber pacemaker may be sufficient.

Quantitative electrophysiological pattern of neurodegeneration in encephalopathies of various origin

Electrophysiological characteristics of patients with encephalopathy of different etiology are presented. Pathogenic mechanisms affecting the electroencephalographic pattern and quantitative components of electroencephalogram are discussed. The aim of the study was to determine a universal quantitative electrophysiological criterion for the evaluation of neurodegenerative changes in the brain of patients with encephalopathy. We analyzed the data of anamnesis, neurological examination, laboratory tests and electroencephalograms from 389 patients with encephalopathy of post-traumatic, infectious, vascular and mixed etiology. Spectral analysis of electroencephalograms was performed and the values of relative quantitative electrophysiological criterion - the ratio of spectral power in the alpha/theta ranges at rest and during the test with hyperventilation were counted. The ratio of spectral power in the alpha/theta ranges was the lowest in patients of older age group and low - in patients with encephalopathy of infectious etiology. The ratio of the spectral power in the alpha-theta ranges in patients with post-traumatic encephalopathy was significantly different depending on the severity of the traumatic brain injury - mild or moderate/severe. We studied the possibilities of practical application of selected electrophysiological criterion - the ratio of spectral power of rhythms in the alpha-theta ranges. We counted this criterion in 150 patients with encephalopathy for the effectiveness evaluation of the neuroprotective therapy with сortexin. The chosen electrophysiological criterion had proved its effectiveness in therapy monitoring in patients with encephalopathy. In this article we demonstrated the advantages of additional neuroprotective therapy with сortexin. Increase in spectral power of alpha rhythm and decrease in spectral power of slow-wave components in the electroencephalographic pattern characterizes successful neuroprotective therapy with neuropeptides, such as сortexin.

Atrial fibrillation in patients after radiofrequency ablation of&#x0D; cavotricuspid isthmus.

The article presents the clinical, instrumental and electrophysiological features of patients who develop atrial fibrillation after cavotricuspid isthmus ablation in 209 patients with typical atrial flutter. Taken together, these features make up a peculiar clinical, instrumental and electrophysiological portrait of patients with post-ablative atrial fibrillation. Comparative analysis of these parameters was made, and it was found that some of them are prognostically significant. Also, we describe the technique of modified intraoperative electrophysiological test of atrial fibrillation induction in patients with typical atrial flutter. We investigated the role of this technique in the occurrence of post ablative atrial fibrillation.

Etiological Search and Epidemiological Profile in Patients Presenting with Hypokalemic Paresis: An Observational Study.

Introduction:Hypokalemia is associated with increased morbidity and at times mortality. “Hypokalemic paralysis”, particularly if recurrent, has often been considered synonymous with “hypokalemic periodic paralysis (HPP)”; however, diseases such as Gitelman syndrome (GS), Bartter syndrome (BS), and renal tubular acidosis (RTA) can have identical presentation. We have tried to explore the etiological spectrum along with epidemiological and certain clinical, biochemical, and electrophysiological features in patients with hypokalemic paralysis.Materials and Methods:In this observational study, 200 appropriate patients with hypokalemic paralysis (serum K+ <3.5 mmol/L) were evaluated for transcellular shift, extra-renal or renal loss of K+ as the underlying etiology of hypokalemia. We took urinary potassium >25 mmol/day as the cutoff for inappropriate renal loss of potassium in presence of hypokalemia. Serum and urinary osmolality along with arterial blood gas analysis were performed in all patients with renal loss of potassium. Serum and urinary sodium, potassium, calcium, magnesium, chloride, and creatinine were measured in normotensive patients with metabolic alkalosis. Hypertensive patients were evaluated with plasma aldosterone and renin activity.Results:Probable GS topped the list involving 28% individuals of the entire cohort while probable BS, distal RTA, and HPP were diagnosed in 20%, 22%, and 19% cases, respectively. Rural tribal population (61%) and age group of 30–40 years suffered the most (48%) with concentration of cases in hot and humid summer months.Conclusions:We suggest that patients with hypokalemic paresis should be evaluated thoroughly to unmask the underlying etiology that may have a different therapeutic and prognostic connotations and not to use the term “periodic” in cases of recurrent hypokalemic paralysis.

Myoclonus in the elderly: A retrospective analysis of clinical and electrophysiological characteristics of patients referred to an electrophysiology laboratory

Background and objectiveLate-onset myoclonus in the elderly is mainly related to dementia or systemic disease. In this report, we aimed to investigate the clinical and electrophysiological features of patients with late-onset myoclonus. Patients and methodWe retrospectively assessed the medical records of patients who were referred to our electromyography laboratory. From these records, we included all patients who had myoclonus which started after the age of 60 years and in whom it was confirmed by polymyography. Demographic, clinical and electrophysiological findings were retrieved from the medical records. ResultsThere were 63 patients with myoclonus. Types of myoclonus were spinal segmental (n = 2), cortical (n = 25) and probable cortico-subcortical involving upper extremities (n = 36). The latter two types displayed reflex sensitivity. Four patients (one with multifocal cortical myoclonus and others with probable cortico-subcortical myoclonus) were diagnosed with probable CJD. Other diagnoses were Parkinsons's disease, Parkinson-plus or dementia syndromes, vascular parkinsonism, polyneuropathy, Celiac disease and post-hypoxic encephalopathy. Eleven patients did not have a specific diagnosis. ConclusionsMyoclonus in our cohort was mostly associated with parkinsonism. Cortical myoclonus is not rare in the elderly age group. Myoclonus in polyneuropathy is irregular, tremor-like with electrophysiological characteristics similar to the cortical subtype.

Observation of clinical and electrophysiological features in patients with distal myasthenia gravis

Objective: To explore the clinical and electrophysiological features and prognosis of distal myasthenia gravis (MG). Methods: Data of MG patients in Beijing Tiantan Hospital from October 2016 to March 2017 were reviewed, including thorough neurological examinations, nerve conduction studies, repetitive nerve stimulations (RNS) and needle electromyographies. Distal MG patients were included and were analyzed as to their clinical and electrophysiological features and response to treatments. Results: Four patients (7.7%) could be classified as distal type among 52 definitely diagnosed MG patients. They had initial symptoms at age 36 to 64 and developed distal limb muscle weakness in the first month to 6 years after the onset of this disease. Hand muscles were preferentially involved in a non-uniform way. And one patient also had leg weakness on his tibialis anterior muscles. RNS showed a more significant decrement at slow rates in distal muscles, compared with proximal muscles. The baseline compound muscle action potentials (CMAP) of the distal affected muscles presented with slightly decreased or fluctuating amplitudes. Their weakness of ocular, bulbar, proximal and distal limb muscles improved generally after administration of acetylcholinesterase inhibitors or steroids plus acetylcholinesterase inhibitors. Electrophysiological reexaminations revealed increased baseline CMAPs, reduced decrement on RNS, and relief of myogenic changes on needle electromyography. Conclusions: Relatively prominent distal limb muscle weakness can be found in a minority of MG patients. Besides profound decrement on slow rate RNS, the involved distal muscles may have a characteristic decreased baseline CMAP, sometimes with a diurnal fluctuation. Distal MG responds well to regular treatments. Its short-term prognosis seems similar to that of common MG with proximal predominance.

Predictors of outcomes and refractoriness in status epilepticus: A prospective study

ObjectiveThe objective of this study was to determine the predictors of outcomes and refractoriness in status epilepticus (SE). MethodsThis is a prospective study of 59 adult patients with SE who were admitted to the Emergency Department between February 2012 and December 2013. The effects of clinical, demographic, and electrophysiologic features of patients with SE were evaluated. To evaluate outcome in SE, STESS, mSTESS, and EMSE scales were used. ResultsLogistic regression analysis showed that being aged ≥65years (p=0.02, OR: 17.68, 95% CI: [1.6–198.4]) for the short term and having potentially fatal etiology (p=0.027, OR: 11.7, 95% CI: [1.3–103]) for the long term were the only independent predictors of poor outcomes; whereas, the presence of periodic epileptiform discharges (PEDs) in EEG was the only independent predictor of refractoriness (p=0.032, OR: 13.7, 95% CI: [1.3–148.5]). The patients with ≥3 Status Epilepticus Severity Score (STESS) did not have poorer outcomes in the short- (p=0.157) and long term (p=0.065). There was no difference between patients with 0–2, 3–4, and ≥4 mSTESS in the short- and long term in terms of outcome (p=0.28 and 0.063, respectively). Also, there was no difference between subgroups (convulsive SE [CSE], nonconvulsive SE [NCSE], and epilepsia partialis continua [EPC]) in terms of STESS and mSTESS. When patients with EPC were excluded, both STESS and mSTESS scores of the patients correlated with poorer long-term outcomes (p=0.025 and 0.017, respectively). The patients with ≥64 points in the Epidemiology-based Mortality in SE-Etiology, age, comorbidity, EEG (EMSE-EACE) score and those with ≥27 points in EMSE-Etiology, age, comorbidity (EMSE-EAC) score did not have poorer outcomes in the short term (p=0.06 and 0.274, respectively) while they had significantly poorer outcome in the long term (p<0.001 and 0.002, respectively). In subgroup analysis, patients with CSE with ≥64 points in EMSE-EACE had significantly poorer outcome in the both short- and long term (p=0.014 and 0.012, respectively), and patients with CSE with ≥27 points in EMSE-EAC had significantly poorer outcome in the long term (p=0.03) but not in the short term (p=0.186). Outcomes did not correlate with EMSE scores in patients with NCSE and EPC. Status epilepticus was terminated with intravenous (IV) levetiracetam (LEV) in 68.75% of patients and with IV phenytoin (PHT) in 83.3% of patients. No statistically significant difference was found between the two groups in terms of efficacy (p=0.334). ConclusionBeing aged ≥65years predicts poor short-term outcomes, and having potentially fatal etiology predicts poor long-term outcomes, which highlight the importance of SE treatment management in the elderly. Both STESS and mSTESS are not predictive for poor outcomes in EPC. Excluding patients with EPC, STESS, and mSTESS could predict poor long-term outcomes but not in the short term in SE. Epidemiology-based Mortality in Status Epilepticus score could predict poor outcome in the long term better than STESS and mSTESS. Specifically, EMSE scores correlated with poor outcome in patients with CSE but not with NCSE and EPC. New scales are needed to predict outcome especially in patients with NCSE and EPC. The presence of PEDs in EEG is a predictor of RSE, and EMSE score can also be used to predict RSE. There was no difference in the efficacy of IV LEV and IV PHT in SE. This study is significant for having one of the longest follow-up periods in the literature.

Demographic and electrophysiological characteristics of patients with prediagnosis of carpal tunnel syndrome admitted to electromyography laboratory

Demographic and electrophysiological characteristics of patients with prediagnosis of carpal tunnel syndrome admitted to electromyography laboratory

Neurons derived from patients with bipolar disorder divide into intrinsically different sub-populations of neurons, predicting the patients' responsiveness to lithium.

Bipolar disorder (BD) is a progressive psychiatric disorder with more than 3% prevalence worldwide. Affected individuals experience recurrent episodes of depression and mania, disrupting normal life and increasing the risk of suicide greatly. The complexity and genetic heterogeneity of psychiatric disorders have challenged the development of animal and cellular models. We recently reported that hippocampal dentate gyrus (DG) neurons differentiated from induced pluripotent stem cell (iPSC)-derived fibroblasts of BD patients are electrophysiologically hyperexcitable. Here we used iPSCs derived from Epstein-Barr virus-immortalized B-lymphocytes to verify that the hyperexcitability of DG-like neurons is reproduced in this different cohort of patients and cells. Lymphocytes are readily available for research with a large number of banked lines with associated patient clinical description. We used whole-cell patch-clamp recordings of over 460 neurons to characterize neurons derived from control individuals and BD patients. Extensive functional analysis showed that intrinsic cell parameters are very different between the two groups of BD neurons, those derived from lithium (Li)-responsive (LR) patients and those derived from Li-non-responsive (NR) patients, which led us to partition our BD neurons into two sub-populations of cells and suggested two different subdisorders. Training a Naïve Bayes classifier with the electrophysiological features of patients whose responses to Li are known allows for accurate classification with more than 92% success rate for a new patient whose response to Li is unknown. Despite their very different functional profiles, both populations of neurons share a large, fast after-hyperpolarization (AHP). We therefore suggest that the large, fast AHP is a key feature of BD and a main contributor to the fast, sustained spiking abilities of BD neurons. Confirming our previous report with fibroblast-derived DG neurons, chronic Li treatment reduced the hyperexcitability in the lymphoblast-derived LR group but not in the NR group, strengthening the validity and utility of this new human cellular model of BD.

A clinical study on the electrophysiological characteristics of patients without recurrence after ablation of persistent atrial fibrillation

BackgroundThe electrophysiological characteristics of patients without recurrence after ablation of persistent atrial fibrillation (AF) have not been systematically determined. This study compared the electrophysiological characteristics in patients with and without recurrence of AF after persistent AF ablation. MethodsForty-five patients without recurrence of AF after persistent AF ablation were enrolled to assess electrophysiological characteristics including pulmonary vein (PV) reconnection, the mitral isthmus (MI) line and the roof line reconduction. Ninety-five patients with recurrence of AF after ablation were used as the control group. ResultsAmong patients without recurrence, recovery of PV conduction was observed in 37 of 45 (82.2%) patients: 3/45 (6.7%) reconnection in 4 veins, 7/45 (15.6%) in 3 veins, 11/45 (24.4%) in 2 veins, and 16/45 (35.6%) in 1 vein. No significant differences were seen in the proportion of patients with PV reconnection compared to patients with recurrence (p>0.05). Among patients without recurrence, the MI line reconduction was observed in 3/45 (6.7%) patients; the roof line conduction was observed in 5/45 (11.1%) patients. In comparison, patients with clinical recurrence of AF had recovery of the MI line conduction in 27/95 (28.4%) and recovery of the roof line conduction in 26/95 (27.4%). Significant differences were seen between these two groups (6.7% vs 28.4%, p=0.004; 11.1% vs 27.4%, p=0.031). ConclusionAlthough a high incidence of PV reconnection was similarly observed in patients with and without recurrence of AF, a lower incidence of lines reconduction was observed in patients without recurrence of AF.

Clinical and Electrophysiological Characteristics of Incessant Atrioventricular Nodal Re-Entrant Tachycardia

This study investigated clinical and electrophysiological findings in patients with incessant atrioventricular nodal reentrant tachycardia (AVNRT). AVNRT is the most frequent cause of paroxysmal supraventricular tachycardia (SVT) and, rarely, incessant SVT. There are a few case reports describing incessant AVNRT. Among 342 patients treated using ablation for AVNRT, we identified 8 patients with incessant AVNRT (2.3%). We describe the clinical and electrophysiological features of patients with incessant AVNRT and compare them with those of patients with paroxysmal AVNRT (n= 334). This study population consisted of 5 men and 3 women with incessant AVNRT. Patients with incessant AVNRT presented more frequently with the fast-slow form than those with paroxysmal AVNRT (63% vs. 14%, respectively, p<0.001). The ejection fraction in patients with incessant AVNRT was significantly lower than that in patients with paroxysmal AVNRT (49 ± 12% vs. 60 ± 8%, p= 0.03). The H-V interval in patients with incessant AVNRT was significantly longer than that in patients with paroxysmal AVNRT. A large circuit path length is inferred by spontaneous tachycardia induction in response to slight changes in sinus rate or random premature beats, suggesting that slight changes in rate produce changes in atrial or nodal refractoriness and provoke SVT. Catheter ablation in the conventional slow pathway region was successful in eliminating SVT. AVNRT can rarely present as incessant SVT, mimicking permanent junctional reciprocating tachycardia, and can be associated with tachycardia-associated cardiomyopathy. Catheter ablation in the slow pathway region leads to long-term success.

Electrophysiological findings in Rasmussen's syndrome.

Rasmussen syndrome is a rare, inflammatory and probably autoimmune disease presenting with epilepsia partialis continua which is generally in the form of myoclonic jerks and involves the upper extremities with or without head involvement. We sought to demonstrate the electrophysiological features in patients with Rasmussen syndrome. We performed continuous electrophysiological recordings of involuntary movement, as well as recordings of startle responses and long latency reflex in three patients with a diagnosis of Rasmussen syndrome. Positive and negative myoclonus were recorded. Startle responses were found to be suppressed. However, long latency reflexes were high in amplitude and one patient even had a C reflex. Stimulus-sensitive positive and negative cortical myoclonus are typical in epilepsia partialis continua of Rasmussen syndrome and degeneration of brainstem and reticulospinal pathways may develop in Rasmussen syndrome.

Dystonia Associated with Idiopathic Slow Orthostatic Tremor.

BackgroundWe aimed to characterize the clinical and electrophysiological features of patients with slow orthostatic tremor.Case ReportThe clinical and neurophysiological data of patients referred for lower limb tremor on standing were reviewed. Patients with symptomatic or primary orthostatic tremor were excluded. Eight patients were identified with idiopathic slow 4–8 Hz orthostatic tremor, which was associated with tremor and dystonia in cervical and upper limb musculature. Coherence analysis in two patients showed findings different to those seen in primary orthostatic tremor.DiscussionSlow orthostatic tremor may be associated with dystonia and dystonic tremor.

P-wave dispersion: What we know till now?

P-wave dispersion is defined as the difference between the maximum and the minimum P-wave duration recorded from multiple different-surface ECG leads. It has been known that increased P-wave duration and P-wave dispersion reflect prolongation of intraatrial and interatrial conduction time and the inhomogeneous propagation of sinus impulses, which are well-known electrophysiologic characteristics in patients with atrial arrhythmias and especially paroxysmal atrial fibrillation. Extensive clinical evaluation of P-wave dispersion has been performed in the assessment of the risk for atrial fibrillation in patients without apparent heart disease, in hypertensives, in patients with coronary artery disease, in patients undergoing coronary artery bypass surgery, in patients with congenital heart diseases, as well as in other groups of patients suffering from various cardiac or non-cardiac diseases. In this paper, we aimed to summarize the measurement methods, current use in different clinical situations, strengths and limitations of the of P-wave dispersion.

Electrophysiologic characteristics of ventricular arrhythmias arising from the aortic mitral continuity-potential role of the conduction system.

Catheter ablation of ventricular arrhythmia (VA) at the fibrous aortic mitral continuity (AMC) has been described, yet the nature of the arrhythmogenic substrate remains unknown. Procedural records of 528 consecutive patients undergoing ablation of VA at Mayo Clinic, Rochester, MN, were reviewed. The electrocardiographic and electrophysiologic characteristics of patients with successful ablation at the AMC were analyzed to characterize the underlying arrhythmogenic substrate. Of the 21 patients (mean age 53.2 ± 13.4 years, 47.6% male) who underwent ablation of VA at the AMC with acute success, prepotentials (PPs) were found at the ablation sites preceding the ventricular electrogram (VEGM) during arrhythmias in 13 (61.9%) patients and during sinus rhythm in 7 (53.8%) patients. VAs with PPs were associated with a significantly higher burden of premature ventricular complexes (PVCs; 26.1 ± 10.9% vs. 14.9 ± 10.1%, P = 0.03), shorter VEGM to QRS intervals (9.0 ± 28.5 milliseconds vs. 33.1 ± 8.8 milliseconds, P = 0.03), lower pace map scores (8.7 ± 1.6 vs. 11.4 ± 0.8, P = 0.001), and a trend toward shorter V-H intervals during VA (32.1 ± 38.6 milliseconds vs. 76.3 ± 11.1 milliseconds, P = 0.06) as compared to those without PP. A strong and positive correlation was found between V-H interval and QRS duration during arrhythmia in those with PPs (B = 2.11, R(2) = 0.97, t = 13.7, P < 0.001) but not in those without PPs. Local EGM characteristics and relative activation time of the His bundle suggest the possibility of conduction tissue as the origin for VA arising from the fibrous AMC. Specific identification and targeting of PPs when ablating VAs at this location may improve procedural success.

Terminal Latency Index (TLI) Abnormalities in Hereditary Neuropathy with Liability to Pressure Palsies (HNPP)

Introduction: The diagnosis of Hereditary Neuropathy with Liability to Pressure Palsy (HNPP) is frequently missed or delayed because of its clinical and electrophysiological heterogeneity. Nonetheless, electrophysiological criteria were published 15 years ago. Our aim was to highlight the Terminal Latency Index (TLI) disorders by describing the electrophysiological characteristics in patients with HNPP. Methods: All the consecutive patients with the clinical and genetic diagnosis of HNPP due to the 1.5Mb deletion of PMP22 or to others mutation or deletion were included. Motor and sensory conductions were studied using surface electrodes placed near the median, ulnar, fibular, tibial, superficial fibular and sural nerves in accordance with standard techniques. The results were compared with our own laboratory standards. Results: All of the 22 included patients had low TLI in the median, ulnar and peroneal nerves, whereas 6% of the patients had low tibial TLI. The other frequent electrophysiological characteristics were increased distal motor latency and low sensory conduction velocity, especially of the median nerve. Conclusions: TLI abnormalities are almost constant in HNPP, which is a great argument to define HNPP as a distally accentuated myelinopathy. TLI disorders should be added to HNPP electrophysiological criteria to improve their diagnosis accuracy.

Adenosine-insensitive right ventricular tachycardia: novel variant of idiopathic outflow tract tachycardia.

A hallmark of idiopathic right ventricular outflow tract (RVOT) tachycardia is its sensitivity to adenosine (ADO), which is consistent with a triggered mechanism. We have identified a novel group of patients with ADO-insensitive, non-reentrant RVOT tachycardia. This study aimed to identify the clinical and electrophysiologic characteristics of ADO-insensitive RVOT tachycardia. The response of ventricular tachycardia (VT) to ADO was evaluated in 46 consecutive patients with inducible sustained idiopathic RVOT tachycardia. The clinical and electrophysiologic characteristics of patients with ADO-insensitive RVOT tachycardia were compared with patients with ADO-sensitive VT and arrhythmogenic right ventricular cardiomyopathy (ARVC) VT. Sustained RVOT tachycardia terminated with ADO in 41 patients (89%), while 5 patients (11%) had ADO-insensitive VT. The electrophysiology study findings of patients with ADO-sensitive and ADO-insensitive RVOT tachycardia were similar. Compared with a group of 10 patients with ARVC, patients with ADO-insensitive RVOT tachycardia had no ARVC-associated electrocardiographic or right ventricular morphologic findings, as well as fewer inducible VT morphologies. Analysis of myocardial biopsies at VT origin sites from 3 of 5 patients with ADO-insensitive RVOT tachycardia demonstrated somatic mutations in the A1 ADO receptor (R296C) in 1 patient and in the inhibitory G protein (F200L) in another patient, as described previously. These mutations were not identified at remote myocardial sites. Over a median follow-up period of 4.8 years, no patients insensitive to ADO developed an ARVC phenotype. Although most forms of idiopathic RVOT tachycardia are characterized by ADO sensitivity, we described a variant of ADO-insensitive VT that, in some cases, can be linked to somatic myocardial mutations involving the A1 ADO receptor-associated cyclic adenosine monophosphate-mediated pathway.

P485: Event-related potentials in patients with primary Sjögren’s syndrome

s of Poster Presentations / Clinical Neurophysiology 125, Supplement 1 (2014) S1–S339 S179 Abstract P484 – Figure 2P484 – Figure 2 neuropathy with a high variable clinical course and outcome. Despite immunotherapy up to 20% of patients remain severely disabled and mortality in the first year is approximately 4%. Aim of this study is to perform an epidemiological analysis of clinical and electrophysiological features of patients admitted in our ward for GBS in last ten years; to test the incidence of different GBS subtypes and their clinical and electrophysiological evolution; to test on our sample the prognostic value of variables known in literature and we suggested integration with new prognostic markers. We collected data prospectively from 89 patients regarding: demographic features, previous infections, clinical manifestations, kind of therapy received, motor deficit and disability (evaluated respectively with MRC sumscore and GBS disability score (GBSDS)). We measured dosage of protein in the cerebrospinal fluid (CSF). Serial nerve conduction studies (NCS) were performed. Differences between groups were compared by Fisher’s exact test. Potential prognostic factors were tested in uni and multivariable logistic analysis and was estimated by regression analysis. 19% of GBS were acute motor axonal neuropathy (AMAN) and showed more severe prognosis. High age was predictive of poor prognosis in acute inflammatory demyelinating neuropathy (AIDP) but not in AMAN. High GBSDS at nadir and cranial nerves involvement were predictive of being enable to run at 1 year. Conduction block did not have a significant distribution in GBS subtypes and showed no correlation with clinical outcome. In NCS performed between 30 and 90 days from the clinical onset, a pathological distal cMAP duration (DcMAPD) represented a distinctive marker of primary demyelinating pathophysiological mechanism, in our sample of GBS. The endurance of pathological DcMAPD showed a predictive value on long term disability in AIDP. This study confirms the key-role of serial NCS for a proper diagnosis of GBS subtypes. Further clinical-electrophysiological studies are necessary to define more inclusive work-up in GBS enabling forecasting of the patients with poorest long term outcome.