Continuous Electrical Activity Research Articles

Treatment of Chronic Muscle Spasm Secondary to Chemotherapy – A Case Report

A known common complication of chemotherapy is the development of muscle spasms. The etiology of which may be multifactorial. However, unlike spasticity secondary to stroke, chronic muscle spasms are not maintained by neurological impulses or lack thereof. Chronic muscle spasms are maintained by continuous spontaneous electrical activity (SEA) throughout the body of the muscle. I have proposed the underlying cause for the SEA is muscle ischemia and the SEA is essentially an arrhythmia similar to what is seen with arrhythmias caused by cardiac ischemia [01]. Regardless of the initial insult that results in chronic muscle spasm, the spasm takes on a life of its own

Stabilization of unstable reentrant atrial tachycardias via fractionated continuous electrical activity ablation (CHAOS study).

Unstable reentrant atrial tachycardias (ATs) (i.e., those with frequent circuit modification or conversion to atrial fibrillation) are challenging to ablate. We tested a strategy to achieve arrhythmia stabilization into mappable stable ATs based on the detection and ablation of rotors. All consecutive patients from May 2017 to December 2019 were included. Mapping was performed using conventional high-density mapping catheters (IntellaMap ORION, PentaRay NAV, or Advisor HD Grid). Rotors were subjectively identified as fractionated continuous (or quasi-continuous) electrograms on 1-2 adjacent bipoles, without dedicated software. In patients without detectable rotors, sites with spatiotemporal dispersion (i.e., all the cycle length comprised within the mapping catheter) plus non-continuous fractionation on single bipoles were targeted. Ablation success was defined as conversion to a stable AT or sinus rhythm. Ninety-seven patients with reentrant ATs were ablated. Of these, 18 (18.6%) presented unstable circuits. Thirteen (72%) patients had detectable rotors (median 2 [1-3] rotors per patient); focal ablation was successful in 12 (92%). In the other 5 patients, 17 sites with spatiotemporal dispersion were identified and targeted. Globally, and excluding 1 patient with spontaneous AT stabilization, ablation success was achieved in 16/17 patients (94.1%). One-year freedom from atrial arrhythmias was similar between patients with unstable and stable ATs (66.7% vs. 65.8%, p = 0.946). Most unstable reentrant ATs show detectable rotors, identified as sites with single-bipole fractionated quasi-continuous signals, or spatiotemporal dispersion plus non-continuous fractionation. Ablation of these sites is highly effective to stabilize the AT or convert it into sinus rhythm.

Utilizing Andrographis paniculata leaves and roots by effective usage of the bioactive andrographolide and its nanodelivery: investigation of antikindling and antioxidant activities through in silico and in vivo studies.

To valorise the bioactive constituents abundant in leaves and other parts of medicinal plants with the objective to minimize the plant-based wastes, this study was undertaken. The main bioactive constituent of Andrographis paniculata, an Asian medicinal plant, is andrographolide (AG, a diterpenoid), which has shown promising results in the treatment of neurodegenerative illnesses. Continuous electrical activity in the brain is a hallmark of the abnormal neurological conditions such as epilepsy (EY). This can lead to neurological sequelae. In this study, we used GSE28674 as a microarray expression profiling dataset to identify DEGs associated with andrographolide and those with fold changes >1 and p-value <0.05 GEO2R. We obtained eight DEG datasets (two up and six down). There was marked enrichment under various Kyoto Encyclopaedia of Genes and Genomes (KEGG) and Gene Ontology (GO) terms for these DEGs (DUSP10, FN1, AR, PRKCE, CA12, RBP4, GABRG2, and GABRA2). Synaptic vesicles and plasma membranes were the predominant sites of DEG expression. AG acts as an antiepileptic agent by upregulating GABA levels. The low bioavailability of AG is a significant limitation of its application. To control these limitations, andrographolide nanoparticles (AGNPs) were prepared and their neuroprotective effect against pentylenetetrazol (PTZ)-induced kindling epilepsy was investigated using network pharmacology (NP) and docking studies to evaluate the antiepileptic multi-target mechanisms of AG. Andrographolide is associated with eight targets in the treatment of epilepsy. Nicotine addiction, GABAergic synapse, and morphine addiction were mainly related to epilepsy, according to KEGG pathway enrichment analysis (p < 0.05). A docking study showed that andrographolide interacted with the key targets. AG regulates epilepsy and exerts its therapeutic effects by stimulating GABA production. Rats received 80 mg/kg body weight of AG and AGNP, phenytoin and PTZ (30 mg/kg i.p. injection on alternate days), brain MDA, SOD, GSH, GABAand histological changes of hippocampus and cortex were observed. PTZ injected rats showed significantly (***p < 0.001) increased kindling behavior, increased MDA, decreased GSH, SOD, GABA activities, compared with normal rats, while treatment AGNPs significantly reduced kindling score and reversed oxidative damage. Finally, we conclude that the leaves and roots of A. Paniculata can be effectively utilized for its major bioactive constituent, andrographolide as a potent anti-epileptic agent. Furthermore, the findings of novel nanotherapeutic approach claim that nano-andrographolide can be successfully in the management of kindling seizures and neurodegenerative disorders.

Stabilization of unstable reentrant atrial tachycardias via fractionated continuous electrical activity ablation (CHAOS study)

Abstract Funding Acknowledgements Type of funding sources: None. Background. Unstable reentrant atrial tachycardias (ATs) (i.e. those with frequent circuit modification or conversion to atrial fibrillation) are challenging to ablate. Purpose. We have tested a strategy to convert unstable reentrant ATs into mappable stable ATs based on the detection and ablation of rotors. Methods. From May 2017 to December 2019, we included all consecutive patients scheduled for ablation of reentrant AT, excluding CTI-dependent atrial flutter, in which the tachycardia circuit was unstable. Operators subjectively identified rotors as sites with fractionated continuous (or quasi-continuous) electrical signals on 1-2 adjacent bipoles of conventional high-density mapping catheters, without dedicated software (Figure, A). Focal ablation of these sites was performed in order to stabilize the AT or convert it into sinus rhythm. In patients without rotors or failed rotor ablation, sites with spatiotemporal dispersion (i.e. all the cycle length comprised within the mapping catheter) plus non-continuous fractionation on single bipoles were targeted (Figure, B). Procedural success was defined as the successful ablation of all inducible ATs, without need of cardioversion, final sinus rhythm and non-inducibility. Follow-up included visits with ECG and 24h Holter-ECG at 3, 6 and 12 months. Results. From May 2017 to December 2019, 97 patients were scheduled for reentrant AT ablation, excluding CTI-dependent atrial flutter. Of these, 18 patients (18.6%; 72.1 ± 8.9 years of age, 9 females) presented unstable circuits and were included. 9 patients (50%) had structural cardiomyopathy, 11 patients (61%) prior atrial arrhythmias ablations, and 4 patients (22%) previous cardiac surgery. 13 patients (72%) had detectable rotors (26 rotors; median 2 [1–3] rotors per patient); focal ablation achieved conversion into stable AT or sinus rhythm in 12 (92%). In the other patient, and the 5 patients without detectable rotors, 17 sites with spatiotemporal dispersion were detected and focally ablated, with success to achieve arrhythmia stabilization in 5 patients (83%). Globally, and excluding one patient with spontaneous AT stabilization, ablation success to stabilize the AT was achieved in 16/17 patients (94.1%). Procedural success was achieved in 16/18 patients (88.9%). Rate of one-year freedom from atrial arrhythmias was 66.7%. In the 9 patients with stable ATs ablated during the same period, procedural success (92.4%) and one-year freedom from atrial arrhythmias (65.8%) were similar (Figure, C). Conclusion. Most unstable reentrant ATs show detectable rotors, identified as sites with single-bipole fractionated quasi-continuous signals, or spatiotemporal dispersion plus non-continuous fractionation. Ablation of these sites is highly effective to stabilize the AT or convert it into sinus rhythm. Abstract FIGURE

Ultra-high resolution mapping and ablation of accessory pathway conduction.

Detailed mapping studies of accessory pathway (AP) conduction have not been previously performed using ultra-high resolution mapping systems. We sought to evaluate the clinical utility of ultra-high resolution mapping systems and the novel "Lumipoint" algorithm in AP ablation. This study included 17 patients who underwent AP mapping using minielectrode basket catheters and Rhythmia systems. Ablation was performed with 4-mm irrigated-tip catheters. Antegrade and retrograde AP conduction was observed in 6 and 16 patients. Atrial activation map was obtained during orthodromic tachycardia and ventricular pacing in 13 (76.5%) and 14 (82.3%) patients, and the earliest activation area was identical. Ventricular activation maps were created during atrial pacing in 3 patients. All maps showed focal activation patterns on global activation histograms, and the valley on the histogram highlighted the earliest activation area. "Complex activation" features further highlighted limited areas with continuous electrical activity during the time period in the majority. APs were located at the mitral and tricuspid annuli in 15 and 2 patients, and all were successfully eliminated with 3.4 ± 0.6s applications. No patients had recurrences during a median follow-up of 15 [10.5-22.5] months. At successful ablation sites, the local atrial and ventricular electrogram amplitudes and ratio tended to be greater, and fusion or continuous electrical activity between the atrial and ventricular components was more frequently observed on the minielectrode than ablation catheter (17/17 vs. 12/17, p = 0.005). Ultra-high resolution activation mapping and a novel algorithm facilitated the AP localization. The local electrogram characteristics differed between the minielectrode and ablation catheters.

Surface Hydrophobicity in Medium Voltage Terminations

The surface hydrophobicity in medium voltage terminations is studied in this paper to see if the performance of aged heat shrink terminations could be improved. Terminations which are used inside of unheated outdoor enclosures can often be subjected to leakage currents and surface discharges along the insulating surface if the environmental conditions inside the enclosure become harsh. The discharge phenomena on the insulating surface is generally not critical but continuous electrical activity on the surface could eventually lead to a flashover or breakdown as the materials age. The effect of surface hydrophobicity was studied by comparing the performance of heat shrink terminations over a longer time in operation. Improvements were done to aged heat shrink indoor terminations which already had signs of discharge occurrence on the termination surfaces. The results indicate that the performance of these aged terminations improved simply by increasing the surface hydrophobicity of the original installation. The improvement can be done by applying a silicone coating on the termination surface. This solution offers a convenient method for improving the performance of aged heat shrink terminations used in unheated outdoor enclosures.

Scalp EEG epileptogenic zone recognition and localization based on long-term recurrent convolutional network

The scalp electroencephalogram (EEG), a non-invasive measure of brain's electrical activity, is commonly used ancillary test to aide in the diagnosis of epilepsy. Usually, neurologists employ direct visual inspection to identify epileptiform abnormalities. Therefore, electroencephalograms have been an essential integral to the researches which aim to automatically detect epilepsy. However, it is difficult because seizure manifestations on scalp EEG are extremely variable between patients, even the same patient. In addition, scalp EEG is usually composed of large number of noise signals which might cover the real features of seizure. To this challenge, we construct an 18-layer Long-Term recurrent convolutional network (LRCN) to automatic epileptogenic zone recognition and localization on scalp EEG. As far as we know, we are the first to train a deep learning classifier to identify seizures through the EEG images, just like neurologists direct visual inspection to identify epileptiform abnormalities. Furthermore, unlike the traditionally methods extracted features from channels manually, which neglected the association of brain's epileptiform abnormalities electrical transmission, seizures is considered as a continuous brain's abnormal electrical activity in our algorithm, from produce at one or several channels, transmission between channels, to flat again after seizures. The method was evaluated in 23 patients with a total of 198 seizures. The classifier shows reasonably good results, with 84% for sensitivity, 99% for specificity, and 99% for accuracy. False Positive Rate per hours exceeds significantly previous results obtained on cross-patient classifiers, with 0.2/h.

Inhomogeneity and complexity in defining fractionated electrograms

Ablation strategies targeting areas of complex fractionated atrial electrograms are not successful for treatment of atrial fibrillation. Fractionation of atrial electrograms may have multiple causes of both pathologic and nonpathologic origin. In order to gain insight into the definitions used for determining areas of fractionation, a literature search was performed using a systematic approach. A PubMed search for studies describing fractionation during human atrial electrophysiologic measurements resulted in 348 articles that were screened for new definitions of fractionation. The 24 studies remaining after screening described 11 different visual definitions for fractionation, 3 automated complex fractionated atrial electrogram detection programs, and 7 new parameters for measuring fractionation. Five different definitions for continuous electrical activity were presented. Electrode properties were often not described, and endocardial bipolar recordings in recent studies used electrode diameters ranging from 1 to 8 mm with interelectrode distance of 2-5 mm. In summary, no uniform definition or recording method is used for measuring fractionation of cardiac atrial electrograms. The different electrophysiologic causes of fractionation and the influence of recording device properties on fractionation complicate identification of true pathologic inhomogeneous conduction. The first step in discrimination between origins of fractionation may be accomplished by relating electrogram morphology to spatial patterns of activation. Before revisiting ablation of areas with fractionated electrograms, we need to determine the correct method for identifying pathologic fractionation.

Neurodevelopmental outcomes after neonatal cardiac surgery: Role of cortical isoelectric activity

ObjectivesNeonates with congenital heart disease are at risk for impaired neurodevelopment after cardiac surgery. We hypothesized that intraoperative EEG activity may provide insight into future neurodevelopmental outcomes. MethodsNeonates requiring surgery had continuous intraoperative EEG and hemodynamic monitoring. The level of EEG suppression was classified as either: slow and continuous; moderate burst suppression; severe burst suppression; or isoelectric (no brain activity for >3 minutes). Follow-up neurodevelopmental outcomes were assessed using the Vineland Adaptive Behavior Scale II (Vineland-II). ResultsTwenty-one neonates requiring cardiac surgery developed a slow and continuous EEG pattern after general anesthesia. Ten neonates (48%) maintained continuous brain electrical activity with moderate burst suppression as the maximum level of EEG suppression. Eleven neonates (52%) developed severe burst suppression that progressed into an isoelectric state during the deep hypothermic period required for circulatory arrest. However, the duration of this state was significantly longer than circulatory arrest times (111.1 ± 50 vs 22.3 ± 17 minutes; P < .001). At a mean follow-up at 5.6 ± 1.0 years, compared with neonates with continuous brain electrical activity, neonates who developed an isoelectric state had lower Vineland-II scores in communication. There was an inverse relationship between composite Vineland-II scores and duration of isoelectric activity (R = −0.75, P = .01). Of neonates who experienced an isoelectric state, durations of >90 minutes were associated with the lowest Vineland-II scores (125.0 ± 2.6 vs 81.1 ± 12.7; P < .01). ConclusionsThe duration of cortical isoelectric states seems related to neurodevelopmental outcomes. Strategies using continuous EEG monitoring to minimize isoelectric states may be useful during complex congenital heart surgery.

Indices of bipolar complex fractionated atrial electrograms correlate poorly with each other and atrial fibrillation substrate complexity.

The pathophysiological relevance of complex fractionated atrial electrograms (CFAE) in atrial fibrillation (AF) remains poorly understood. The aim of this study was to comprehensively investigate how bipolar CFAE correlates with unipolar electrogram fractionation and the underlying electrophysiological substrate of AF. Ten-second unipolar AF electrograms were recorded using a high-density electrode from the left atrium of 20 patients with AF (10 with persistent AF and 10 with paroxysmal AF) undergoing cardiac surgery. Semiautomated bipolar CFAE algorithms: complex fractionated electrogram-mean, interval confidence interval, continuous electrical activity, average complex interval, and shortest complex interval were evaluated against AF substrate complexity measures following fibrillation wave reconstruction derived from local unipolar activation time. The effect of interelectrode spacing and electrode orientation on bipolar CFAE was also examined. All 5 semiautomated bipolar CFAE algorithms showed poor correlation with each other and AF substrate complexity measures (conduction velocity, number of waves or breakthroughs per AF cycle, and electrical dissociation). Bipolar CFAE also correlated poorly with fractionation index derived from unipolar electrograms. Increased interelectrode spacing resulted in an increase in bipolar CFAE detected except for the interval confidence interval algorithm. CFAE appears unaffected by bipolar electrode orientation (vertical vs horizontal). By contrast, unipolar fractionation index correlated well with AF substrate complexity measures and can be regarded as a marker for conduction block. The lack of pathophysiological relevance of bipolar CFAE analysis may in part contribute to the divergent and limited success rates of catheter ablation strategies targeting CFAE.

Selective Complex Fractionated Atrial Electrograms Targeting for Atrial Fibrillation Study (SELECT AF)

Background— This study compared generalized complex fractionated atrial electrograms (CFAE) ablation versus a selective CFAE ablation strategy targeting areas of continuous electric activity. Methods and Results— Subjects with symptomatic, persistent/high-burden paroxysmal atrial fibrillation (AF) were enrolled at 6 centers (n=86) and randomized to 1 of 2 arms. For group I, all CFAE regions with an interval confidence level &gt;7 were ablated followed by pulmonary vein isolation (PVI). For group II, only CFAE sites with continuous electric activity were ablated followed by PVI. For PVI, all 4 PV antra were isolated with confirmed entrance block. Subjects were followed for 1 year with a visit, ECG, and 48-hour Holter every 3 months. Symptoms were confirmed by loop recording. The primary end point was freedom from arrhythmia &gt;30 seconds at 1 year. For both group I and II, CFAE ablation prolonged AF cycle length (25±33 versus 23±33 ms; P =0.78) and resulted in similar rates of AF termination (37% versus 28%; P =0.42). Radiofrequency duration during CFAE ablation was significantly less in group II (23±20 versus 38±20 minutes; P =0.002). At 1-year follow-up, freedom from AF/atrial flutter/atrial tachycardia recurrence was significantly higher in group I versus group II after 1 procedure (50% versus 28%; P =0.03). There were also significantly fewer repeat procedures in group I (13% versus 36%; P =0.021). Conclusions— Continuous electric activity ablation+PVI result in a similar incidence of acute AF termination with significantly less radiofrequency time. However, incidence of repeat procedures and long-term recurrence of AF/atrial flutter/atrial tachycardia are significantly lower using generalized CFAE ablation+PVI. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00926783

The 2010 eruption of Eyjafjallajökull: Lightning and plume charge structure

Six Lightning Mapping Array (LMA) stations were deployed in April 2010 around Eyjafjallajökull volcano in southern Iceland. Single‐station LMA observations were made during the first explosive period (14–18 April), and three‐dimensional LMA observations were made during the second explosive period (5–22 May). The single‐station observations revealed that continuous RF electrical activity caused by high rates of small vent discharges occurred during the first explosive period, but not the second, indicating that the strength of vent charging varied between the first and second explosive periods. During the second explosive period, very little lightning was detected between 5 and 10 May, while moderate rates of lightning were detected between 11 and 21 May, signaling that another change occurred on 11 May that affected plume electrification. The data do not make clear if it was changing eruptive activity or changing meteorological activity that resulted in the sudden onset of lightning. The plume charge structure during the second explosive period was inferred from the three‐dimensional lightning data, showing that the dominant charge structure varied between a positive monopole and a negative‐over‐positive dipole. The predominance of a low‐altitude region of positive charge and the observation that electrical activity was concentrated near the vent indicate that net positive vent charging was dominating the electrification.

WORK, REST AND PLAY; THE CLINICAL SPECTRUM OF NON–CONVULSIVE STATUS EPILEPTICUS

IntroductionNon–convulsive status epilepticus (NCSE) is defined as prolonged seizure activity in the absence of motor features or a change in behaviour and/or mental processes from baseline associated with continuous epileptiform...

A New Perspective on Temperamental Shyness: Differential Susceptibility to Endoenvironmental Influences

In this review, we adapt and extend a model recently used to account for differences in risk and resiliency outcomes to explain individual differences in temperamental shyness. The differential susceptibility to environmental influences model posits that heightened biological sensitivity and reactivity in the individual can predict different outcomes for better or for worse, depending on environmental influences outside (i.e., exogenous) of the individual. In this article, we extend this existing model and argue that the environment can also be conceptualized as a unique set of dynamic conditions and influences operating within (i.e., endogenous) the individual that are orthogonal to some biological sensitivity factors. In this new model, continuous brain electrical activity at rest constitutes one endogenous environmental condition that can vary (leftward to rightward) and influence gene expression to confer different outcomes, for better (sociability) or for worse (shyness). We then discuss how this model can be tested, as well as its potential implications for theory, development, and practice.

Catheter Ablation for Persistent Atrial Fibrillation

A new era of atrial fibrillation (AF) treatment began in 1997–1998 with the discovery that triggers within the pulmonary veins initiate AF and reports that elimination of these triggers is successful in treating AF in its paroxysmal form.1–3 However, in patients with persistent AF, the success rate of exclusive pulmonary vein isolation is substantially lower.4,5 To improve the outcome of persistent AF ablation, different ablation strategies have been explored, but to date the optimal strategy has not been defined. Although some groups argue that limited ablation, including pulmonary vein isolation and, if present, ablation of nonpulmonary vein triggers, is sufficient for persistent AF ablation, other groups, including ours, favor more extensive, substrate-based ablation in addition to pulmonary vein isolation. In this review, we will discuss the rationale for a substrate-based ablation strategy to treat persistent AF and show why elimination of triggers is not sufficient in most patients with persistent AF. Response by Roten et al on p 1232 In a simple model, an electric impulse in AF can form because of abnormalities in impulse generation (triggers) or can result from abnormal impulse propagation (reentry). By a strict definition, a trigger is a focal source of new impulse generation. The mechanism by which a new impulse can form is either abnormal automaticity or triggered activity. Trigger-ablation protocols target these sources of new impulse generation. Abnormal impulse propagation, on the other hand, depends on altered substrate properties causing nonuniform or slowed conduction. This in turn causes multiple forms of wave reentry thought to be responsible for AF perpetuation: random reentry (multiple wavelets), macro- and microreentry, or functional reentry (rotors). Substrate-based ablation strategies aim to abate abnormal impulse propagation and interrupt any form of atrial reentry. Triggers of paroxysmal AF are mainly located in the pulmonary …

Abstract 9284: Selective Complex Fractionated Electrogram Targeting For Atrial Fibrillation Study (Select AF): A Multicenter, Randomized Trial

Introduction: This study compared pulmonary vein isolation (PVI) plus generalized CFAE ablation vs PVI plus selective CFAE ablation, specifically areas of continuous electrical activity (CEA)(ClinicalTrials.gov NCT00926783 ). Methods: Patients with persistent/high burden AF (age 63±9 yr, LA size 42±6 mm) were enrolled at 6 centers (n=86) &amp; randomized. For the generalized arm, all CFAE regions with an interval confidence level &gt;7 were ablated followed by PVI. For the selective arm, only those CFAE sites with CEA were ablated followed by PVI. For PVI, all PV antra were isolated with confirmed entrance block. Patients were followed with ECG, &amp; 48-hr Holter every 3 mos. AF symptoms were confirmed by loop recording. The primary endpoint was freedom from AF &gt;30 sec at 1 year. Results: Both generalized &amp; selective CFAE ablation prolonged AF cycle length (26±32 ms vs 22±33 ms, p=0.6). AF termination rates were also similar: 37% for generalized &amp; 31% for selective (p=0.6). In both groups, PVI was achieved after CFAE ablation in all patients. RF duration was significantly less in the selective arm vs the generalized arm (25±21 vs. 40±21 min, p=0.008). However, at 1 year follow-up, freedom from AF/AT recurrence was significantly higher in the generalized vs the selective arm after 1 procedure (59% vs 24%, p=0.005). Looking at AF/AT recurrence post 1st or repeat ablation, freedom from recurrence at one year in the generalized arm was 62%, still higher than 33% in the selective arm (p=0.02). There was a trend towards fewer repeat procedures in the generalized vs selective arm (14% vs 33%, p=0.057). Complications included tamponade (n=1) and a sedation-related event (n=1). Conclusions: In persistent/high burden AF, selective CFAE ablation + PVI results in similar AF cycle length prolongation and termination rates with significantly less RF time. However, long-term freedom from AF/AT is significantly better using generalized CFAE ablation + PVI.

Validation of a novel algorithm for quantification of the percentage of signal fractionation in atrial fibrillation

Catheter ablation for paroxysmal atrial fibrillation (AF) is rapidly becoming a standard practice. There is literature to support that catheter ablation of persistent AF requires additional 'substrate modification'. In clinical practice, operators rely on automated fractionation maps created by three-dimensional anatomic mapping systems to rapidly assess complex 'fractionated' signals (CFAE). These systems use differing algorithms to automate the process. The agreement between operators and contemporary algorithms has not been examined. We sought to assess the agreement between operators and a novel method of quantification calculating percentage fractionation (PF). Expert opinion on 80 atrial electrogram 4 s signals of varying levels of activity were gathered and pooled for comparison. Twelve independent experts visually quantified the signal fractionation and offered a threshold level for ablation. We developed an algorithm to find sites with high continuous electrical activity, or high PF. Correlation between experts and PF was 0.78 [P < 0.01, 95% confidence interval (CI) (0.68-0.86)]. Receiver operating characteristics curve sensitivity and specificity for PF were 0.7727 and 0.8103 at the optimal cut-off point of 58.45 PF with area under curve 0.89 CI (0.80-0.99). The PF statistic represents a more robust and intuitive measure to represent fractionated atrial activity; importantly it demonstrates excellent agreement with expert users and presents a new standard for algorithm assessment. Use of a PF statistic should be considered in automated mapping systems.

Stability of Complex Fractionated Atrial Electrograms: A Systematic Review

Stability of CFAE. The efficacy of complex fractionated atrial electrograms (CFAE) ablation as additional substrate modification in atrial fibrillation (AF) patients has been shown to be highly variable. Recently, the validity of sequential CFAE mapping has been challenged by concerns regarding temporal stability of CFAE. Existing studies on CFAE stability are small with very different CFAE definitions. Here, we undertook a systematic literature review to address these controversial findings. A systematic search of the scientific literature was performed through to September 1, 2011. From a total of 162 manuscripts, 7 were identified to contain assessment of the temporal stability of CFAE in human AF. These studies included a total of 96 (80 persistent/16 paroxysmal AF) patients (79% male, mean 58 years old). Varying CFAE mapping techniques or definitions were utilized. CFAE stability averaged 81% between 2 high-density sequential fractionation maps over an average time interval of 19 minutes. However, CFAE stability only averaged at 75% from shorter term continuous recordings (mean 15 comparisons within 75 seconds). Although the variability in CFAE cycle length was small (12-15 ms), coefficients of variation in continuous electrical activity were high (up to 300%). The overall spatial distribution of CFAE was found to be stable. Nevertheless, sequential mapping may not capture all CFAE sites given their dynamic characteristics. CFAE are temporally variable in keeping with the diverse mechanisms underlying their existence. The dynamic nature of CFAE will continue to pose a challenge for electrophysiologists in search of critical sites requiring ablation to combat AF. (J Cardiovasc Electrophysiol, Vol. 23, pp. 980-987, September 2012).

Relationship among complex signals, short cycle length activity, and dominant frequency in patients with long-lasting persistent AF: A high-density epicardial mapping study in humans

Complex fractionated atrial electrograms (CFAEs) and regions of high dominant frequency (DF) both may identify sites critical to the maintenance of atrial fibrillation (AF). CFAEs may be defined by either (1) complex multicomponent electrograms (EGMs) and/or continuous electrical activity (multicomponent/continuous EGM) or (2) discrete high-frequency EGMs. The purpose of this study was to test if the 2 definitions of CFAE identify the same arrhythmia substrate and determine the relationship of CFAE to areas of high DF. High-density epicardial mapping of the posterior left atrium was performed in 10 patients with long-lasting persistent AF. Point-by-point analysis was performed to determine the spatial distribution and correlation of CFAE defined as either (1) multicomponent/continuous-EGMs or (2) AF cycle length <120 ms. Additionally, spatial analysis was performed to determine the relationship of high DF sites to CFAE sites defined by each of the 2 definitions. The percentage of sites deemed CFAE varied markedly between patients and was different depending on the definition of CFAE adopted. There was a poor correlation between CFAE defined by multicomponent/continuous EGMs and AF cycle length <120 ms (r = 0.18). High DF sites were arranged in clusters evenly distributed throughout the posterior left atrium, with 4.2 ± 1.0 high DF clusters per patient. Although there was poor point-by-point correlation between multicomponent/continuous EGMs and high DF sites (r = 0.107), spatial analysis revealed that 96% of multicomponent/continuous EGMs were found adjacent to and partially surrounding (≤5 mm) high DF sites. There is poor anatomic overlap between CFAE defined by multicomponent/continuous EGMs and CFAE defined by AF cycle length <120 ms. Multicomponent/continuous EGMs are found adjacent to and surrounding sites of high DF. Further studies are needed to determine the mechanisms responsible for these different signals.

The Characteristics of the Electrograms at the Site of AF Termination by Ganglionated Plexi Ablation

AF termination was often occurred during ganglionated plexi (GP) ablation. The purpose of this study was to characterize the electrograms at the site of AF termination by GP ablation. Method: Eighteen patients with AF termination by GP ablation were studied. In case of patients with sinus rhythm, AF was induced by rapid atrial pacing. The sites where vagal response was evoked by high-frequency stimulation were determined as GP sites and ablated. The bipolar electrograms were recorded in a 4.5-s window before the RF delivery. Result: AF termination was seen at superior left GP ablation in 3 patients, anterior right in 2 patients, inferior left in 6 patients, and inferior right (in 7 patients). Continuous electrical activity (CEA) was seen at the termination site in 16 (89%) patients. Other 2 patients without CEA, cycle length was 207±18 ms. The maximum duration of CEA was 1.8±0.3 of 4.5 sec. There were 2 patients with only CEA at the termination sites during all recording period. The maximum amplitude of CEA in 16 patients was 0.58±0.99 mV. Conclusion: The electrograms at the sites of AF termination by GP ablation show mainly transient CEA with relatively low voltage.