Prospective 1-year results of atrial fibrillation ablation using the pentaspline pulsed field ablation catheter: The initial French experience

BACKGROUND

Pulsed field ablation has recently emerged as an interesting non-thermal energy for atrial fibrillation ablation. At a time of rapid spread of this technology, there is still a lack of prospective real-life data.

AIM

To describe multicentre prospective safety and 1-year efficacy data in three of the first French centres to use pulsed field ablation.

METHODS

All consecutive patients undergoing a first pulsed field ablation were included prospectively. The primary outcome was freedom from documented atrial arrhythmia. The safety endpoint was a composite of major adverse events. Univariate and multivariable analyses, including patient and procedural characteristics, were performed to identify factors predictive of recurrence.

RESULTS

Between May 2021 and June 2022, 311 patients were included (paroxysmal atrial fibrillation in 53%, persistent atrial fibrillation in 35% and long-standing persistent atrial fibrillation in 11%). Additional non-pulmonary vein pulsed field ablation applications were performed in 104/311 patients. One-year freedom from arrhythmia recurrence was 77.6% in the overall population and was significantly higher in patients with paroxysmal atrial fibrillation (88.4%) compared with patients with persistent atrial fibrillation (69.7%; P<0.001) and those with long-standing persistent atrial fibrillation (49.0%; P<0.001). The major complication rate was 2.6% (tamponade in four patients, stroke in two patients and coronary spasm in one patient). Besides the usual predictors of recurrences (left atrium size, CHA2DS2-VASc score, type of atrial fibrillation), the presence of atrial fibrillation at procedure start was independently associated with arrhythmia recurrence (hazard ratio: 2.04, 95% confidence interval: 1.10-3.77).

CONCLUSION

In this prospective multicentre real-world study, pulsed field ablation for atrial fibrillation ablation seems to be associated with a good safety profile and rather favourable acute and 1-year success rates.

Systematic use of half normal saline during ablation of ventricular tachycardia in structural heart disease

BACKGROUND

Efficiency and safety of ablation using half normal saline (HNS) has been shown in refractory ventricular tachycardia (VT), but no evaluation in unselected larger populations has been made.

OBJECTIVE

To evaluate the efficiency and safety of systematic HNS ablation in VT ablation.

METHODS

All successive VT ablations in patients with structural heart disease from 2018 to 2021 used HNS in our center and were retrospectively included.

RESULTS

One hundred seventy-seven successive VT ablation procedures using HNS have been performed in 148 patients (91% males, mean 64 ± 12 years, ischemic cardiomyopathy 64%, left ventricular ejection fraction 38 ± 13%). A mean of 19 ± 7.5 min of RF was delivered, with a mean power of 44 ± 7 W. Relevant complications happened in 9% (strokes 2%, tamponades 3%, atrioventricular block during septal ablations 5%). Over a mean follow-up of 15 ± 9 months, VT recurred in 46%. Final recurrence rate after one or several procedures was 36% (18 months follow-up). Number of VT episodes decreased from 14 ± 35 before to 2.5 ± 10 after ablation (p < .0001) and number of ICD shocks decreased from 4.8 ± 6.8 to 1.5 ± 0.8 (p = .027).

CONCLUSION

Systematic use of HNS during VT ablations in patients with structural heart disease leads to long-term recurrences rates and complications in the range of what is reported using normal saline. Although controlled studies are needed for demonstrating the superiority of such attitude, the use of HNS in every scar-related VT ablation seems safe for standard cases and may be furthermore useful in case of refractory arrhythmias due to difficult-to-ablate substrates.

A worldwide survey on incidence, management and prognosis of oesophageal fistula formation following atrial fibrillation catheter ablation: The POTTER-AF study

AIMS

Oesophageal fistula represents a rare but dreadful complication of atrial fibrillation catheter ablation. Data on its incidence, management and outcome are sparse.

METHODS AND RESULTS

This international multicenter registry investigates the characteristics of oesophageal fistulae after treatment of atrial fibrillation by catheter ablation. A total of 553,729 catheter ablation procedures (radiofrequency: 62.9%, cryoballoon: 36.2%, other modalities: 0.9%) were performed at 214 centers in 35 countries. In 78 centers 138 patients (0.025%, radiofrequency: 0.038%, cryoballoon: 0.0015% (p<0.0001)) were diagnosed with an oesophageal fistula. Periprocedural data were available for 118 patients (85.5%). Following catheter ablation, the median time to symptoms and the median time to diagnosis were 18 (7.75, 25; range: 0-60) days and 21 (15, 29.5; range: 2-63) days, respectively. The median time from symptom onset to oesophageal fistula diagnosis was 3 (1, 9; range: 0-42) days. The most common initial symptom was fever (59.3%). The diagnosis was established by chest computed tomography in 80.2% of patients. Oesophageal surgery was performed in 47.4% and direct endoscopic treatment in 19.8%, and conservative treatment in 32.8% of patients. The overall mortality was 65.8%. Mortality following surgical (51.9%) or endoscopic treatment (56.5%) was significantly lower as compared to conservative management (89.5%) (odds ratio 7.463 (2.414, 23.072) p<0.001).

CONCLUSIONS

Oesophageal fistula after catheter ablation of atrial fibrillation is rare and occurs mostly with the use of radiofrequency energy rather than cryoenergy. Mortality without surgical or endoscopic intervention is exceedingly high.

Correlations Between Endocardial Voltage Mapping, Diagnosis, and Genetics in Patients With Arrhythmogenic Right Ventricular Cardiomyopathy

The relations between endocardial voltage mapping and the genetic background of patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) have not been investigated so far. A total of 97 patients with proved or suspected ARVC who underwent 3-dimensional endocardial mapping and genetic testing have been retrospectively included. Presence, localization, and size of scar areas were correlated to ARVC diagnosis and the presence of a pathogenic variant. A total of 78 patients (80%) presented with some bipolar or unipolar scar on endocardial voltage mapping, whereas 43 carried pathogenic variants (44%). Significant associations were observed between presence of endocardial scars on voltage mapping and previous or inducible ventricular tachycardia, right ventricular function and dimensions, or electrocardiogram features of ARVC. A total of 60 of the 78 patients (77%) with an endocardial scar fulfilled the criteria for a definitive arrhythmogenic right ventricular dysplasia diagnosis versus 8 of 19 patients (42%) without scar (p = 0.003). Patients with a definitive diagnosis of ARVC had more scars from any location and the scars were larger in patients with ARVC. In the 68 patients with a definitive diagnosis of ARVC, the presence of any endocardial scar was similar whether an ARVC-causal mutation was present or not. Only scar extent was significantly greater in patients with pathogenic variants. There was no difference in the presence and characteristics of scars in PKP2 mutated versus other mutated patients. The 3-dimensional endocardial mapping could have an important role for refining ARVC diagnosis and may be able to detect minor forms with otherwise insufficient criteria for diagnosis. The trend for larger scar extent were observed in mutated patients, without any difference according to the mutated genes.

Hemodynamical consequences and tolerance of sustained ventricular tachycardia

AIMS

Factors underlying clinical tolerance and hemodynamic consequences of monomorphic sustained ventricular tachycardia (VT) need to be clarified.

METHODS

Intra-arterial pressures (IAP) during VT were collected in patients admitted for VT ablation and correlated to clinical, ECG and baseline echocardiographical parameters.

RESULTS

114 VTs from 58 patients were included (median 67 years old, 81% ischemic heart disease, median left ventricular ejection fraction 30%). 61 VTs were untolerated needing immediate termination (54%). VT tolerance was tightly linked to the evolution of IAPs. Faster VT rates (p<0.0001), presence of resynchronization therapy (p = 0.008), previous anterior myocardial infarction (p = 0.009) and more marginally larger baseline QRS duration (p = 0.1) were independently associated with VT tolerance. Only an inferior myocardial infarction was more often present in patients with only tolerated VTs vs patients with only untolerated VTs in multivariate analysis (OR 3.7, 95% CI 1.4-1000, p = 0.03). In patients with both well-tolerated and untolerated VTs, a higher VT rate was the only variable independently associated with untolerated VT (p = 0.02). Two different patterns of hemodynamic profiles during VT could be observed: a regular 1:1 relationship between electrical (QRS) and mechanical (IAP) events or some dissociation between both. VT with the second pattern were more often untolerated compared to the first pattern (78% vs 29%, p<0.0001).

CONCLUSION

This study helps to explain the large variability in clinical tolerance during VT, which is clearly related to IAP. VT tolerance may be linked to resynchronization therapy, VT rate, baseline QRS duration and location of myocardial infarction.

Phase analysis for ventricular arrhythmia prediction: A retrospective monocentric cohort study

BACKGROUND

Prediction of ventricular arrhythmias (VA) mostly relies on left ventricular ejection fraction (LVEF), but with limited performance. New echocardiographic parameters such as mechanical dispersion have emerged, but acoustic window sometimes precludes this measurement. Nuclear imaging may be an alternative. We aimed to assess the ability of mechanical dispersion, measured with phase standard deviation (PSD) on radionuclide angiocardiography (RNA), to predict VAs.

METHODS

This retrospective monocentric observational study included all patients who underwent a tomographic RNA from 2015 to 2019. Phase analysis yielded PSD and follow-up was examined to identify VAs, heart transplantation, and death.

RESULTS

The study population consisted of 937 patients, mainly with LVEF ≤ 35% (425, 45%). Most had ischemic (334, 36%) or dilated cardiomyopathies (245, 26%). We identified 86 (9%) VAs. PSD was strongly associated with the occurrence of VA [hazard ratio per 10 ms increase (HR10) 1.12 (1.09-1.16)], heart transplantation [HR10 1.09 (1.06-1.12)], and death [HR10 1.03 (1.00-1.05)]. The association between PSD and VA persisted after adjustment for age, sex, QRS duration, LVEF, global longitudinal strain (GLS), and echocardiography-assessed mechanical dispersion.

CONCLUSION

The occurrence of ventricular arrhythmias was predicted by mechanical dispersion assessed by RNA, even after adjustment for LVEF and GLS.

Premature Ventricular Contractions and Ultra-High-Definition Mapping. Contribution and Limits

Background

The utility of ultra-high definition mapping (UHDM) for ablation of premature ventricular contractions (PVC) remains undetermined. The aim of this study was to investigate UHDM for PVC ablation, and additionally to compare to conventional technique.

Methods

Twenty patients investigated using UHDM were prospectively included and analyzed. Electrophysiological caracteristics and results were compared to 40 patients ablated using fluoroscopy only.

Results

2541±2033 EGMs and 331±240 PVC beats were recorded for each patient. Surfaces of isochronal activations were 2.3±1.7 and 6.9±6.1 cm² (first 10 and 20 ms). Local scar was present in 40% and local block in 65%. Areas of pace-mapping > 95, 90 and 85% concordance were 1.5±3.4, 2.1±3.9 and 3.3±5 cm². Mean distance between the ablation site and the site of best pace-mapping or of earliest activation was 8±8 mm and 5±7 mm. Pre-potential was noted in 17% vs 26% controls (ns). QS pattern was present in 83% vs 83% controls (ns), and earliest activation was - 31±50 vs - 25±14 ms in controls (ns). Procedure (100±36 vs 190±51 min, p< 0.0001) and fluoroscopy duration (15±9 vs 24±9 min, p=0.005) were shorter in controls. Acute success was achieved in 65% patients with UHDM and in 72% controls (p=ns) with lower residual PVC burden in the control group. Over a follow-up of 19±12 months, long-term success was similar between groups (65 vs 68%).

Conclusions

UHDM may reveal poorly recognized activation features and PVC mechanism. In this series, conventional mapping was quicker and did clinically as well as UHDM.

Incidence, epidemiology, diagnosis and prognosis of atrio-oesophageal fistula following percutaneous catheter ablation: a French nationwide survey

AIMS

Rate, incidence, risk factors, and optimal management of atrio-oesophageal fistula (AOF) after catheter ablation for atrial fibrillation (AF) remain obscure.

METHODS AND RESULTS

All French centres performing AF ablation were identified and surveys were sent concerning the number of procedures, eventual cases of AOF, and characteristics of such cases. Eighty-two of the 103 centres (80%) performing AF ablation in France were included, with a total of 129 286 AF ablations since 2006 (93% of the whole procedures in France). Thirty-three AOF were reported (reported rate 0.026% per procedure) with a stable reported annual incidence despite the increasing number of procedures. Sensitivity of computed tomography (CT) scan for AOF was 81%. Mortality was 60%, significantly lower in case of surgical corrective therapy (31 vs. 93%, P = 0.001).

CONCLUSION

The reported rate of AOF after AF ablation in this nationwide survey was 0.026%, with a stable reported annual incidence over time. A normal CT scan does not rule out the diagnosis and should be repeated in case of suspicion. Prognosis remains poor with a mortality of 60% and crucially dependant of immediate surgical correction. No clear protective strategy has been proven effective.

Relationships between left ventricular mass and QRS duration in diverse types of left ventricular hypertrophy

AIMS

Hypertrophic cardiomyopathy (HCM) may be associated with very narrow QRS, while left ventricular hypertrophy (LVH) may increase QRS duration. We investigated the relationships between QRS duration and LV mass (LVM) in subtypes of abnormal LV wall thickness.

METHODS AND RESULTS

Automated measurement of LVM on MRI was correlated to automated measurement of QRS duration on ECG in HCM, left ventricular non compaction (LVNC), left ventricular hypertrophy (LVH), and controls with healthy hearts. Uni and multivariate analyses were performed between groups including explanatory variables expected to influence LVM and QRS duration. The relationships between QRS duration and LVM were further studied within each group. Two hundred and twenty-one HCM, 28 LVNC, 16 LVH, and 40 controls were retrospectively included. Mean QRS duration was 92 ms for HCM, 104 for LVNC, 110 for LVH, and 92 for controls (P < 0.01). Mean LVM was 100, 90, 108, and 68 g/m2 (P < 0.01). QRS duration, LVM, hypertension, maximal wall thickness, and late gadolinium enhancement were significantly linked to HCM in multivariate analysis (w/wo bundle branch block). An independent negative correlation was found between LVM and QRS duration in the HCM group, while the relationship was reverse in LVNC, LVH, and controls.

CONCLUSION

QRS duration increases with LVM in LVNC, LVH, or in healthy hearts, while reverse relationship is present in HCM. These relationships were independent from other parameters. These results warrant additional investigations for refining diagnosis criteria for HCM in the future.

Remote Atrial Fibrillation Burden Estimation Using Deep Recurrent Neural Network

OBJECTIVE

The atrial fibrillation burden (AFB) is defined as the percentage of time spent in atrial fibrillation (AF) over a long enough monitoring period. Recent research has suggested the added prognostic value of using the AFB compared to a binary diagnosis. We evaluate, for the first time, the ability to estimate the AFB over long-term continuous recordings, using a deep recurrent neutral network (DRNN) approach.

METHODS

The models were developed and evaluated on a large database of p = 2,891 patients, totaling t = 68,800 hours of continuous electrocardiography (ECG) recordings from the University of Virginia. Specifically, 24h beat-to-beat time series were obtained from a single portable ECG channel. The network, denoted ArNet, was benchmarked against a gradient boosting (XGB) model, trained on 21 features including the coefficient of sample entropy (CosEn) and AFEvidence that is derived from the number of irregular points revealed by the Lorenz plot. The generalizations of ArNet and XGB were also evaluated on the independent PhysioNet LTAF test database.

RESULTS

the absolute AF burden estimation error [Formula: see text], median and interquartile, on the test set, was 1.2 (0.1-6.7) for ArNet and 2.8 (0.9-11.7) for XGB for AF individuals. Generalization results on LTAF were consistent with [Formula: see text] of 2.7 (1.1-14.7) for ArNet and 3.6 (1.0-16.7) for XGB.

CONCLUSION

This research demonstrates the feasibility of AFB estimation from 24h beat-to-beat interval time series utilizing DRNNs.

SIGNIFICANCE

The novel data-driven approach enables robust remote diagnosis and phenotyping of AF.

Incidence, epidemiology, risk factors and prognosis of atrio-esophageal fistula following percutaneous catheter ablation. An exhaustive natiowide registry

Introduction

A rare but often fatal complication of atrial fibrillation (AF) ablation is the formation of an atrioesophageal fistula (AEF) whose true prevalence and risk factors remain obscure.

Objective

To determine incidence, epidemiology, risk factors and prognosis of AEF using a – as exhaustive as possible – nationwide survey

Method

All French centers performing AF ablation were identified and survey were sent concerning the habits, techniques of AF ablation and eventual cases of AEF.

Results

82 of the 103 centers (80%) performing ablation of AF in France were included in the study performing 129286 ablations from 2006 (93% of the total AF ablation in France). 33 AEF were declared (26 AEF and 4 esopericardial fistula) (0.026% risk per procedure) with a stable annual incidence over time, unchanged after the advent of thermal probe. Sensititvity of CT scan for AEF diagnosis was 81%. Mortality was 60%, significantly lower in case of surgical mangement (31 vs 93%, p=0.001). No case of AEF happened after cryoablation and only two AEF occurred in redo ablation. In multivariate analysis, lack of use of contact force catheters and the realization of posterior/roof ablation lines emerged as independent factors associated with the risk of AEF with OR 23.6 (95% CI [4.5; 21]) p=0.0002 and OR 3.7 (95% CI [1.1, 13]) p=0.04) while the lack of thermal probes remained of borderline significance.

Conclusion

The rate of AEF after AF ablation in a nationwide and well exhaustive survey can be evaluated to 0.026% with an annual incidence remaining stable over time. A normal CT scan does not rule out the diagnosis. Prognosis remains poor with a mortality of 60% and crucially dependant of immediate surgical correction.

Funding Acknowledgement

Type of funding source: None

Relations between voltage mapping and diagnosis and genetics in patients with arrhythmogenic right ventricular cardiomyopathy

Introduction

Relations between voltage mapping and diagnosis or genetic background in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) have not been investigated so far.

Objective

We investigate if diagnosis or genetic background were linked to voltage mapping in ARVC.

Method

70 patients with proved or suspected ARVC undergoing 3D endocardial mapping and genetic testing have been retrospectively included. Localisation and extension of bipolar low voltage areas were correlated to ARVC diagnosis and presence of a culprit mutation.

Results

44/70 fulfilled ARVC Task Force criteria and 25/70 had culprit mutations. Endocardial (38/44 vs 16/26, p=0.02) and especially infero-lateral scars (31/44 vs 9/26, p=0.003) were more often present in patients fulfilling Task force criteria vs suspected ARVC, with larger scars (area 23±27 vs 8±11 cm2, p=0.04, perimeter 17±10 vs 11±7 cm, p=0.03) (sensitivity 86%). Mutated patients had more infero-lateral (19/25 vs 21/45, p=0.01), multiple (12/20 vs 11/34, p=0.04) and larger scars (perimeter 21±10 vs 12±7 cm, p=0.01) vs non mutated patients. In patients with ARVC diagnosed according to the Task Force criteria, there was a trend toward more infero-lateral (p=0.09) and larger scars (p=0.08) in mutated cases. PKP2-mutated cases tended to have less ourflow tract (p=0.08) and less multiple scars (p=0.09) vs other mutations.

Conclusion

3D endocardial mapping could have an important role for ARVC diagnosis and may be able to detect minor forms with otherwise insufficiant criteria for diagnosis. More frequent and larger infero-lateral scars are present in mutated patients with bordeline differences according to the mutated genes.

Funding Acknowledgement

Type of funding source: None

Coagulation and heparin requirements during ablation in patients under oral anticoagulant drugs

BACKGROUND

Anticoagulation during catheter ablation should be closely monitored with activated clotting time (ACT). However vitamin K antagonists (VKA) or direct oral anticoagulant drugs (DOAC) may act differently on ACT and on heparin needs. The aim of this study was to compare ACT and heparin requirements during catheter ablation under various oral anticoagulant drugs and in controls.

METHODS

Sixty consecutive patients referred for ablation were retrospectively included: group I (n = 15, VKA), group 2 (n = 15, uninterrupted rivaroxaban), group 3 (n = 15, uninterrupted apixaban), and group 4 (n = 15, controls). Heparin requirements and ACT were compared throughout the procedure.

RESULTS

Heparin requirements during the procedure were significantly lower in patients under VKA compared to DOAC, but similar between DOAC patients and controls.Activated clotting time values were significantly higher in patients under VKA compared to DOAC and similar in DOAC patients versus controls. Furthermore, anticoagulation control as evaluated by the number/proportion of ACT> 300 as well as the time passed over 300 seconds was significantly better in patients under VKA versus DOAC, without significant differences between DOAC and controls. Finally, the number of patients/ACT with excessive ACT values was significantly higher in VKA versus DOAC patients versus controls.There was no significant difference between rivaroxaban and apixaban for ACT or heparin dosing throughout the procedure.

CONCLUSION

Vitamin K antagonists allowed less heparin requirement despite reaching higher ACT values and more efficient anticoagulation control (with more excessive values) compared to patients under DOAC therapy and to controls. There was no difference in heparin requirements or ACT between DOAC patients and controls.

Creation of sinus rhythm and paced maps using a single acquisition step: the "one acquisition-two maps" technique-a feasibility study

PURPOSE

Scars and abnormal electrograms may significantly differ according to the activation wavefront. We propose a new fast technique for reliable comparison between sinus rhythm and ventricular pacing using a single map acquisition and the Rhythmia™ 3D mapping system.

METHODS

A special programming of the external stimulator was assuring full stable regular paced-beat bigeminy during spontaneous rhythm. A first map was acquired for the spontaneous cardiac beat. Then the window of detection was moved to the following paced beat, and a second map was available after recalculation by the system, depicting activation and voltage of the paced cardiac beat at the same locations, with an exactly the same number of beats in both maps.

RESULTS

Thirty patients with structural heart disease referred for ablation of ventricular tachycardia underwent this protocol, who were compared with 19 similar patients undergoing repeated maps. Duration of the mapping was significantly shorter compared to controls (34 ± 12 vs 57 ± 14 min, p < 0.0001) without differences in the number of electrograms (6978 ± 7067 vs 9554 ± 4424 for sinus rhythm map and 6610 ± 7240 vs 7783 ± 3804 for paced map, p = ns for both). The technique cannot be completed in five patients (17%), because of arrhythmogenicity, mechanical right bundle branch block, hemodynamical impairment, or bradycardia.

CONCLUSION

We propose a novel technique for performing maps during sinus rhythm and ventricular pacing using a single acquisition. Beside time saving, this will allow more strict comparisons between different activation wavefronts.

Hybrid surgical ablation for persistent or long standing persistent atrial fibrillation: A French single centre experience

BACKGROUND

Hybrid ablation for the treatment of atrial fibrillation is a single combined procedure consisting in a minimally thoracoscopic surgical ablation followed by a catheter ablation. This promising technique is recommended in persistent atrial fibrillation according to the current guidelines but is not routinely performed in France, mainly due to the absence of reimbursement by the French National Health Insurance.

AIMS

The aim of this prospective and single-centre study was to analyse, for the first time in France, the feasibility, efficacy and complication rates of hybrid ablation in patients with persistent atrial fibrillation.

METHODS

Hybrid ablation was performed in 15 consecutive patients (13 men, mean age 61±6 years) with persistent (7 patients) or long standing persistent (8 patients) atrial fibrillation.

RESULTS

Hybrid ablation was completed in 14/15 patients. Eleven patients returned in sinus rhythm during the procedure. Two patients (13%) had major per-procedural complications and 2 had minor complications. During an average follow-up of 25±6 months, 6 patients (40%) underwent a redo catheter ablation because of atrial tachycardia, mainly peri-mitral atrial flutter. At 1 year follow up, 14/15 patients were in sinus rhythm, including 11 free of antiarrhythmic drugs.

Chest pain in Brugada syndrome: Prevalence, correlations, and prognosis role

BACKGROUND

Brugada syndrome (BrS) is sometimes diagnosed because of chest pain. Prevalence and characteristics of such BrS patients are unknown.

METHODS

A total of 200 BrS probands were retrospectively included. BrS diagnosis made because of chest pain (n = 34, 17%) was compared to the other ones.

RESULTS

BrS probands with diagnosis because of chest pain had significantly more often smoker habits, increased body mass index, and familial history of coronary artery disease but less frequently previous resuscitated sudden death/syncope or atrial fibrillation. Presence of coronary spasm and familial coronary artery disease were independently associated with BrS diagnosed because of chest pain. They presented more often with spontaneous type 1 ST elevation (59% vs 26%, P = .0004) and higher ST elevation during the episode of chest pain compared to other patients or compared to baseline electrocardiogram after chest pain resumption. ST elevation during chest pain was lower compared to ajmaline test. A total of 20% of them had significant coronary artery disease and four (11%) had coronary spasm, and they experienced more often recurrent chest pain episodes (24% vs 5%, P = .0002). Presence of chest pain at BrS diagnosis was not correlated to future arrhythmic events in univariate analysis. Only previous sudden cardiac death (SD)/syncope and familial SD were still significantly associated with outcome in multivariate analysis.

CONCLUSION

Chest pain is a common cause for BrS diagnosis, although major part is not apparently explained by ischemic heart disease. Mechanisms leading to chest main remain unknown in the other ones. ST elevation is higher in this situation but does not seem to carry poor prognosis.

Correlations between arrhythmogenic substrate and noninvasive risk stratification in ischemic heart disease patients modifications by radiofrequency ablation

INTRODUCTION

Several noninvasive risk factors for ventricular arrhythmias have been described in postmyocardial infarction (MI) patients, whose relationships with scar characteristics and modifications by ablation are unknown.

METHODS

Twenty-two patients with previous MI referred for ventricular tachycardia ablation were prospectively included. ECG, heart rate variability (HRV), signal-averaged ECG (SA-ECG), and T wave alternans (TWA) were performed before and after radiofrequency ablation. Scar areas were correlated to preablation parameters. Pre and postablation parameters were furthermore compared.

RESULTS

Left ventricular ejection fraction and some spectral and time-domain HRV parameters were significantly correlated to the scar areas. QRS duration was larger after vs before ablation (120 ± 29 vs 105 ± 22 msec, P = .01). No significant modification in time or spectral domain of HRV was observed. There was no significant change in TWA and SA-ECG before and after ablation. Borderline decreases in quantitative TWA parameters were noted in patients with positive TWA and successful ablation procedure.

CONCLUSION

Some noninvasive risk factors were linked to the scar areas, but few were significantly modified after ablation. Larger populations are needed to demonstrate significant differences or correlations.

Structural evidence for a new elaborate 3D-organization of the cardiomyocyte lateral membrane in adult mammalian cardiac tissues

AIMS

This study explored the lateral crest structures of adult cardiomyocytes (CMs) within healthy and diseased cardiac tissue.

METHODS AND RESULTS

Using high-resolution electron and atomic force microscopy, we performed an exhaustive quantitative analysis of the three-dimensional (3D) structure of the CM lateral surface in different cardiac compartments from various mammalian species (mouse, rat, cow, and human) and determined the technical pitfalls that limit its observation. Although crests were observed in nearly all CMs from all heart compartments in all species, we showed that their heights, dictated by the subsarcolemmal mitochondria number, substantially differ between compartments from one species to another and tightly correlate with the sarcomere length. Differences in crest heights also exist between species; for example, the similar cardiac compartments in cows and humans exhibit higher crests than rodents. Unexpectedly, we found that lateral surface crests establish tight junctional contacts with crests from neighbouring CMs. Consistently, super-resolution SIM or STED-based immunofluorescence imaging of the cardiac tissue revealed intermittent claudin-5-claudin-5 interactions in trans via their extracellular part and crossing the basement membrane. Finally, we found a loss of crest structures and crest-crest contacts in diseased human CMs and in an experimental mouse model of left ventricle barometric overload.

CONCLUSION

Overall, these results provide the first evidence for the existence of differential CM surface crests in the cardiac tissue as well as the existence of CM-CM direct physical contacts at their lateral face through crest-crest interactions. We propose a model in which this specific 3D organization of the CM lateral membrane ensures the myofibril/myofiber alignment and the overall cardiac tissue cohesion. A potential role in the control of sarcomere relaxation and of diastolic ventricular dysfunction is also discussed. Whether the loss of CM surface crests constitutes an initial and common event leading to the CM degeneration and the setting of heart failure will need further investigation.

Usefulness of interim analyses in portending study results in antipsychotic and antidepressant trials

It is unknown whether interim analyses portend final study results. Fatigue, pressure to complete trials and recruitment differences may mitigate against this. We examined the similarity of efficacy results of the first and second half of recruited patients to complete trials and explore possible intervening variables. Using data from the NewMeds repository of patient level data from placebo-controlled randomized trials of antipsychotics (AP) (22 studies, n=7056) and antidepressants (AD) (39 studies, n=12,217) we compared treatment effect size (placebo vs. active treatment) of the first and second half of patients recruited in completed trials. We found that in AP studies median difference in treatment effect between cohorts was -0.03, indicating that overall first and second cohorts yielded similar results. In AD studies, median difference between cohorts was 0.04, indicating that overall the second cohort had slightly larger active-placebo-difference. Overall, on average there were minimal differences in effect size between the first and the second cohorts, and in 30 of 39 trials interim results were a good estimate of the results on the 2nd cohort. In AD trials first and second cohort results were more similar when the proportion of patients per study centre and recruitment time of the two cohorts was similar. Results suggest that interim analyses in AD and AP studies may reliably serve to estimate ultimate effects and, at least in AD trials, are more accurate when the same sites are used to a similar extent and recruitment time of the two consequent cohorts is similar.

Statistics of flexible chain configurations

When Monte Carlo methods are employed to study the statistical dimensions of flexible polymer chains, it is necessary that the sampling be statistically unbiased. One Monte Carlo procedure is the so-called "slithering snake" technique, which has proved to be very useful. A question arises, however, as to how long it takes for a "slithering snake" to be completely regenerated to avoid biasing the samples around a particular configuration. It is demonstrated theoretically and verified by Monte Carlo studies that the number of iterations required to completely regenerate a sample polymer is a quadratic function of the chain length. This verification applies to chains in dilute solution but may not hold for bulk polymers.

Early onset anxiolytic efficacy after a single dose of pregabalin: double-blind, placebo- and active-comparator controlled evaluation using a dental anxiety model

To evaluate acute onset of anxiolytic activity using a dental anxiety model, 89 patients were randomised to double-blind single dose pregabalin 150 mg, alprazolam 0.5 mg or placebo 4 h before a scheduled dental procedure. A Dental Anxiety Total score >12 (moderate-to-severe) without meeting Diagnostic and Statistical Manual of Mental Disorders (Fourth edition) (DSM-IV) anxiety disorder criteria was required. Efficacy and safety, assessed 2, 2.5, 3, 3.5 and 4 h postdose, included 100 mm Visual Analogue Scale for Anxiety (VAS-Anxiety; primary outcome), 100 mm VAS-Sedation and Time-to-Onset of Action Scale (TOAS), a patient-rated anti-anxiety drug-benefit scale (no [0] to full benefit [10]). Mixed model analysis found significantly greater VAS-A improvement slopes for pregabalin (t = -2.47; P = 0.014) and alprazolam (t = -2.39; P = 0.018). There was a significant improvement versus placebo in the TOAS from 2 h through endpoint in alprazolam patients and from 3 h onward in pregabalin patients. Pregabalin produced significantly greater increases in VAS-Sedation versus placebo from 2.5 h through 4 h (2 h onward for alprazolam). Notably, there was a higher correlation between TOAS and VAS-Sedation (r = +0.58) than VAS-Anxiety (r = -0.50) on Spearman's analysis. The majority of Adverse Effects (AEs) were mild, and the most frequent for pregabalin, alprazolam, and placebo, respectively, were fatigue (N = 7, 7, 3), dizziness (N = 6, 3, 3), attention disturbance (N = 3, 1, 0), somnolence (N = 3, 0, 0), feeling abnormal (N = 0, 2, 0) and balance disorder (N = 0, 2, 0). These results suggest that onset of clinically meaningful anxiolytic effect after single-dose pregabalin occurs within the first 3-4 h. Additional research is needed to determine whether anxiolytic effect occurs in generalized anxiety disorder populations by day 1 or within 3-4 h post-first dose.

Is Speed of Onset of Anti-anxiety Efficacy with Pregabalin Influenced by Starting Dose?

Objective:

There appears to be no dose-response effect for pregabalin at doses of 300-600 mg, and a modest dose-response effect in the range of 150-300 mg. The goal of the current investigation was to determine the effect of the starting dose on the speed of onset of anxiolytic efficacy.

Methods:

Data were analyzed from 7 trials of outpatients with DSM-IV GAD and a HAM-A total score ≥18. Starting doses of pregabalin ranged from 100 mg (N=301) or 150 mg (N=104), to 200 mg (N=167) and 300 mg (N=388). Assessment of early improvement included the HAM-A total score and CGI-Severity and Improvement scores.

Results:

The mean Week 1 HAM-A change score was similar for a starting dose of 200 mg/d with no titration (-8.24) when compared to patients who started on 200 mg/d and then titrated up to 400 mg/d on Day 4 (-8.64). The mean Week 1 HAM-A change score was somewhat higher for patients started on 300 mg/d, and then titrated to 450 mg/d on Day 4/5 (-8.84) when compared to patients started on a lower (100/150 mg/d) dose and titrated on Day 5 to 400/450 mg/d (-7.32). Starting on a dose of 300 mg/d with no titration resulted in an intermediate Week 1 change score (-7.87). The interaction of starting dose and titration schedule with baseline anxiety severity will be summarized in detail.

Conclusion:

The initial dose of pregabalin appears to have only a weak effect on the speed of onset of anxiolytic improvement.

[Analysis of the interaction between nicotinic acetylcholine receptor and Na+,K(+)-ATPase in the rat skeletal muscle and the Torpedo electric organ membrane preparation]

The interaction between the nicotinic acetylcholine receptor and Na+,K(+)-ATPase described previously was further studied in isolated rat diaphragm and in a membrane preparation of Torpedo californica electric organ. Three specific agonists of the nicotinic receptor: acetylcholine, nicotine and carbamylcholine (100 nmol/L each), all hyperpolarized the non-synaptic membranes of muscle fibers by up to 4 mV. Competitive antagonists of nicotinic acetylcholine receptor, d-tubocurarine (2 mcmol/L) or alpha-bungarotoxin (5 nmol/L) completely blocked the acetylcholine-induced hyperpolarization indicating that the effect requires binding of the agonists to their specific sites. The noncompetitive antagonist, proadifen (5 mcmol/L), exerted no effect on the amplitude of hyperpolarized but decreased K0.5 for this effect from 28.3 +/- 3.6 nmol/L to 7.1 +/- 2.3 nmol/L. Involvement of the Na+,K(+)-ATPase was suggested by data demonstrating that three specific Na+,K(+)-ATPase inhibitors: ouabain, digoxin or marinobufagenin (100 nmol/L each), all inhibit the hyperpolarizing effect of acetylcholine. Acetylcholine did not affectation either the catalytic activity of the Na+,K(+)-ATPase purified from sheep kidney or the transport activity of the Na+,K(+)-ATPase in the rat erythrocytes, i. e. in preparations not containing acetylcholine receptors. Hence, acetylcholine does not directly affect the Na+,K(+)-ATPase. In a Torpedo membrane preparation, ouabain (< or = 100 nmol/L) increased the binding of the fluorescent ligand: Dansyl-C6-choline (DCC). No ouabain effect was observed either when the agonist binding sites of the receptor were occupied by 2 mmol/L carbamylcholine, or in the absence Mg2+, when the binding of ouabain to the Na+,K(+)-ATPase is negligible. These results indicate that ouabain only affects specific DCC binding and only when bound to the Na+,K(+)-ATPase. The data obtained suggest that, in two different systems, the interaction between the nicotinic acetylcholine receptor and the Na+,K(+)-ATPase specifically involve the ligand binding sites of these two proteins.

[Functional interaction between nicotinic cholinergic receptors and Na, K-ATPase in the skeletal muscles]

Acetylcholine (ACh) hyperpolarized the rat diaphragm muscle fibers by 4.5 +/- 0.8 mV (K0.5 = = 36 +/- 6 nmol/l). The AC-induced hyperpolarization was blocked by d-tubocurarine and ouabain in nanomolar concentrations. This effect of ACh was not observed in cultured C2C12 muscle cells and in Xenopus oocytes with expressed embryonic mouse muscle nicotinic acetylcholine receptors (nAChR) or with neuronal alpha 4 beta 2 nAChR. In membrane preparations from the Torpedo californica electric organ, containing both nAChR and Na, K-ATPase, 10 nmol/l ouabain modulated the binding kinetics of the cholinergic ligand dansyl-C6-choline to the nAChR. These results suggest that in-sensitive alpha 2 isoform) and nAChR in a state with high affinity to Ach and d-tubocurarine may form a functional complex in which binding of ACh to nAchR is coupled to activation of the Na, K-ATPase.

[Porcine kidney extract contains a specific inhibitor of the ouabain-sensitive alpha2-isoform of Na, K-ATPase present in rat diaphragm fibres]

In experiments on isolated rat diaphragm muscle, acetylcholine (100 nmol/l) hyperpolarized muscle fibres due to activation of the alpha 2 isoform of Na,K-ATPase. This hyperpolarization was blocked in a dose-dependent manner by ouabain (K0.5 = 8 +/- 4 nmol/l) as well as by a solution of porcine kidney extract (10 kDa cut-off filtration), with the K0.5 approximately equal to a 1:20,000-fold dilution. The inhibitory activity of the developed slowly over a period of 3 hours and, in contrast to ouabain, was still present after 1 hour of washing. Ouabain, but not the extract, inhibits Rb+ uptake in human erythrocytes that only express the alpha = 1 isoform of Na, K-ATPase. Our data suggest that in rat skeletal muscle the alpha 1 isoform of Na,K-ATPase is primarily responsible for ionic homeostasis, while the alpha 2 isoform provides a "regulatable" function and may be controlled by cholinergic stimulation and/or endogenous digitalis-like factors (EDLFs). Porcine kidney extract contains a factor (M. W. < 10 kDa) that selectively inhibits the rat alpha 2 isoform and differs from ouabain. Our experimental protocol can be used as a highly sensitive physiological assay for factors that selectively inhibit the alpha 2 isoform of Na,K-ATPase.

Feasibility of atmospheric pressure desorption/ionization on silicon mass spectrometry in analysis of drugs

The feasibility of atmospheric pressure desorption/ionization on silicon mass spectrometry (AP-DIOS-MS) for drug analysis was investigated. It was observed that only compounds with relative high proton affinity are efficiently ionized under AP-DIOS conditions. The limits of detection (LODs) achieved in MS mode with midazolam, propranolol, and angiotensin II were 80 fmol, 20 pmol, and 1 pmol, respectively. In MS/MS mode the LODs for midazolam and propranolol were 10 fmol and 5 pmol, respectively. The good linearity (r(2) > 0.991), linear dynamic range of 3 orders of magnitude, and reasonable repeatability showed that the method is suitable for quantitative analysis.

Quantitative determination of 1 -hydroxypyrene in bovine urine samples using high-performance liquid chromatography with fluorescence and mass spectrometric detection

An analytical method was developed to determine quantitatively 1-hydroxypyrene (OHP) in bovine urine samples. The procedure includes an enzymatic hydrolysis to cleave the conjugated metabolite, an enrichment step using solid phase extraction with a non-polar rinse step and elution with dichloromethane. A final clean-up on silicagel was performed before high-performance liquid chromatography (HPLC) analysis and fluorescence detection. Alternatively, HPLC and electrospray ionization in the negative ion mode applying selective ion monitoring acquisition revealed to be a highly sensitive detection method allowing the quantitation of low pg of OHP in the urine samples. The method was successfully applied to the determination of OHP in bovine urine samples from animals living in urban and rural areas. Urine concentrations of OHP were significantly higher (median 8.6 microg l(-1)) of bovines living close to a highway.

The effect of relocation after a natural disaster

Twenty-five women remaining in a city devastated by an earthquake were compared with 24 relocated survivors and 25 comparison women. The women were administered a structured PTSD interview, the Hamilton Depression Scale, and SCL-90-R. The women in both exposed groups showed significantly more symptoms of avoidance, arousal, and total PTSD than the comparison group. The women in the relocated city had significantly higher depression scores than the women in the earthquake city. On the SCL-90-R, relocated women were most symptomatic and comparison group women were least symptomatic. Relocation after a disaster appears to be associated more with risk for depression than with PTSD in situations where recovery is delayed following the trauma.

Physically abused adolescents: behavior problems, functional impairment, and comparison of informants' reports

OBJECTIVE

This study, like earlier studies that focused on younger abused children, ascertained whether physically abused adolescents exhibited increased internalizing and externalizing behaviors. Relevance to pediatric practice is discussed.

DESIGN

A cross-sectional design was used to compare the behavior of physically abused adolescents and comparison adolescents using self-reports, parent reports, and teacher reports. The level of agreement among raters was also examined.

PARTICIPANTS

The subjects were 99 physically abused adolescents between the ages of 12 and 18 years, who were recruited from Child Protective Services. Comparison subjects were 99 community-recruited nonabused adolescents who were matched for age, gender, and income with the abused adolescents.

MEASURES

The behavior of the adolescents was assessed using the Child Behavior Checklist, and the comparable Youth Self-Report and Teacher Report Form, which are widely used measures of behavioral and emotional problems. The Child Global Assessment Scale was also used as a measure of functional impairment and of the need for mental health services.

RESULTS

Parents and teachers rated the problems of abused adolescents as significantly greater than the problems of nonabused adolescents on all checklist subscales. Abused adolescents reported significantly greater problems only on externalizing behavior subscales. In addition, based on interviewer ratings, physically abused adolescents exhibited significantly greater functional impairment.

CONCLUSIONS

Similar to previous research on abused children, physically abused adolescents exhibit externalizing and internalizing behavior problems and experience greater functional impairment. Parent, teacher, and adolescent reports of externalizing behaviors were similar, but physically abused adolescents reported fewer internalizing behaviors than did the other informants.

Oxidation of the skeletal muscle Ca2+ release channel alters calmodulin binding

This study presents evidence for a close relationship between the oxidation state of the skeletal muscle Ca2+ release channel (RyR1) and its ability to bind calmodulin (CaM). CaM enhances the activity of RyR1 in low Ca2+ and inhibits its activity in high Ca2+. Oxidation, which activates the channel, blocks the binding of 125I-labeled CaM at both micromolar and nanomolar Ca2+ concentrations. Conversely, bound CaM slows oxidation-induced cross-linking between subunits of the RyR1 tetramer. Alkylation of hyperreactive sulfhydryls (<3% of the total sulfhydryls) on RyR1 with N-ethylmaleimide completely blocks oxidant-induced intersubunit cross-linking and inhibits Ca2+-free 125I-CaM but not Ca2+/125I-CaM binding. These studies suggest that 1) the sites on RyR1 for binding apocalmodulin have features distinct from those of the Ca2+/CaM site, 2) oxidation may alter the activity of RyR1 in part by altering its interaction with CaM, and 3) CaM may protect RyR1 from oxidative modifications during periods of oxidative stress.

Posttraumatic stress disorder and family functioning in adolescent cancer

Twenty three adolescents with a history of cancer, 27 physically abused adolescents, and 23 healthy, nonabused adolescents were administered structured posttraumatic stress disorder (PTSD) interviews and self-report questionnaires regarding family functioning. Thirty five percent of adolescent cancer subjects met criteria for lifetime PTSD as compared to only 7% of the abused adolescents: 17% of the cancer subjects and 11% of the abuse subjects met criteria for current PTSD. Adolescents with cancer viewed their mothers and fathers as significantly more caring and more protective than the comparison and abused adolescents. Cancer subjects who met criteria for lifetime PTSD saw their families as significantly more chaotic than those who did not have PTSD. Eighty three percent of cancer subjects who had lifetime PTSD also had mothers who had PTSD.