Point Of Ablation Research Articles

Simplification of resetting response in slow/fast atrioventricular nodal reentrant tachycardia: the 3 catheters approach

Abstract Background The resetting response is a maneuver that helps identify the anterograde limb of slow/fast atrioventricular nodal reentrant tachycardia (AVNRT). The actual described maneuver involved a 5 catheters approach, and the related complications are poorly described.(1) Purpose We describe a simplified approach with 3 catheters and the related complications of the maneuver. Methods A quadripolar catheter was placed in the His bundle region; a decapolar catheter in the coronary sinus (CS) and a 4 mm tip non irrigated or irrigated catheter was used for pacing and ablation. An 8.5 French Sl0 sheath was used to ensure contact and stability. In confirmed slow/fast AVNRT using the fast pathway as the retrograde limb (earliest retrograde atrial activity located in the parahisian region), a single decremental atrial extrastimulus was delivered at the lower part of the triangle of Koch and 2-3 cm inside the CS on the roof. Pacing maneuver was started near the end of the QRS complex and decremented by 10 ms per interval. The higher atrial signal with the best A/V ratio on the CS catheter was used as sense reference for resetting response. The end point of ablation was non inducibility. Results Ten patients were included in a 4-month period, comprising 2 redo procedures. The maneuver was not performed in 4 patients (40%) due to non-sustained tachycardia. Atrial fibrillation was induced in 2 patients (20%) during the maneuver systematically due to an atrial extrastimulus preceding the H potential (negative HA interval). In the 4 remaining patients with successful resetting response, the HA interval in successful ablation spot varies between 31 to 82 ms. The involved anterograde limb was the right extension in 3 (75%) and the left extension in 1 (25%). Conclusion Resetting response can be performed with a 3 catheters approach, the main limitation is non sustained tachycardia, and atrial fibrillation induced by short coupled extrastimulus.Resseting response in LIE and RIE

Predictors of recurrence in patients without non-inducibility of ventricular tachycardia at the end of ablation.

Ventricular tachycardia (VT) non-inducibility at the end of ablation is associated with a less likely VT recurrence. However, it is not clear whether we should use VT non-inducibility as a routine end point of VT ablation. The aim of this study was to evaluate VT recurrence in patients in whom VT non-inducibility was not achieved at the end of the radiofrequency (RF) ablation and the factors attributing to the VT recurrence. We analyzed that 62 patients in whom VT non-inducibility was not achieved at the end of the RF ablation were studied. Over 2 years, 22 (35%) of the cases had VT recurrences. A multivariate analysis showed that an LVEF ≥35% (HR: 0.19; 95% CI: 0.06-0.49; p < .01) and elimination of the clinical VT as an acute ablation efficacy (HR: 0.23; 95% CI: 0.04-0.81; p=.02) were independent predictors of fewer VT recurrences. RF ablation was associated with a 91.1% reduction in VT episodes. Even if VT non-inducibility was not achieved, patients with an LVEF ≥35% or in whom the clinical VT could be eliminated might be prevented from having VT recurrences. The validity of the VT non-inducibility of any VT should be evaluated considering each patient's background and the results of the procedure.

Single point of care embolization, ablation, and stabilization of unstable pelvic metastatic disease

A 56-year-old man presented with intractable pain and inability to ambulate. Computed tomography showed an osteolytic renal cell carcinoma metastasis in the left ilium causing instability (Fig 1). Following a multidisciplinary discussion, percutaneous embolization, ablation, and pelvic stabilization were planned subsequent to radiation of the tumor. Triple therapy was necessary as nonembolized vascular renal cell carcinoma metastases may cause heat sink, incomplete ablation, and tumor progression, resulting in the failure of hardware.

Two-Photon Cell and Tissue Level Laser Ablation Methods to Study Morphogenetic Biomechanics.

Laser ablation is routinely performed to infer mechanical tension in cells and tissues. Here we describe our method of two-photon laser ablation at the cellular and tissue level in mouse embryos. The primary outcome of these experiments is initial retraction following ablation, which correlates with, and so can be taken as a measure of, the tensile stress that structure was under before ablation. Several experimental variables can affect interpretation of ablation tests. Pre-test factors include differences in physical properties such as viscoelasticity between experimental conditions. Factors relevant during the test include viability of the cells at the point of ablation, image acquisition rate and the potential for overzealous ablations to cause air bubbles through heat dissipation. Post-test factors include intensity-biased image registration that can artificially produce apparent directionality. Applied to the closing portion of the mouse spinal neural tube, these methods have demonstrated long-range biomechanical coupling of the embryonic structure and have identified highly contractile cell populations involved in its closure process.

Non-thermal Electroporation Ablation of Epileptogenic Zones Stops Seizures in Mice While Providing Reduced Vascular Damage and Accelerated Tissue Recovery.

In epilepsy, the most frequent surgical procedure is the resection of brain tissue in the temporal lobe, with seizure-free outcomes in approximately two-thirds of cases. However, consequences of surgery can vary strongly depending on the brain region targeted for removal, as surgical morbidity and collateral damage can lead to significant complications, particularly when bleeding and swelling are located near delicate functional cortical regions. Although focal thermal ablations are well-explored in epilepsy as a minimally invasive approach, hemorrhage and edema can be a consequence as the blood-brain barrier is still disrupted. Non-thermal irreversible electroporation (NTIRE), common in many other medical tissue ablations outside the brain, is a relatively unexplored method for the ablation of neural tissue, and has never been reported as a means for ablation of brain tissue in the context of epilepsy. Here, we present a detailed visualization of non-thermal ablation of neural tissue in mice and report that NTIRE successfully ablates epileptic foci in mice, resulting in seizure-freedom, while causing significantly less hemorrhage and edema compared to conventional thermal ablation. The NTIRE approach to ablation preserves the blood-brain barrier while pathological circuits in the same region are destroyed. Additionally, we see the reinnervation of fibers into ablated brain regions from neighboring areas as early as day 3 after ablation. Our evidence demonstrates that NTIRE could be utilized as a precise tool for the ablation of surgically challenging epileptogenic zones in patients where the risk of complications and hemorrhage is high, allowing not only reduced tissue damage but potentially accelerated recovery as vessels and extracellular matrix remain intact at the point of ablation.

Epicardial and Endocardial Ablation Based on Channel Mapping in Patients With Ventricular Tachycardia and Chronic Chagasic Cardiomyopathy: Importance of Late Potential Mapping During Sinus Rhythm to Recognize the Critical Substrate.

BackgroundVentricular tachycardia (VT) in patients with chronic chagasic cardiomyopathy (CCC) is associated with considerable morbidity and mortality. Catheter ablation of VT in patients with CCC is very complex and challenging. The main goal of this work was to assess the efficacy of VT catheter ablation guided by late potentials (LPs) in patients with CCC.Methods and ResultsSeventeen consecutive patients with refractory VT and CCC were prospectively included in the study. Combined endo‐epicardial voltage and late activation mapping were obtained during baseline rhythm to define scarred and LP areas, respectively. The end point of the ablation procedure was the elimination of all identified LPs. Epicardial and endocardial dense scars (<0.5 mV) were detected in 17/17 and 15/17 patients, respectively. LPs were detected in the epicardial scars of 16/17 patients and in the endocardial scars of 14/15 patients. A total of 63 VTs were induced in 17 patients; 22/63 (33%) were stable and entrained, presenting LPs recorded in the isthmus sites. The end point of ablation was achieved in 15 of 17 patients. Ablation was not completed in 2 patients because of cardiac tamponade or vicinity of the phrenic nerve and circumflex artery. Three patients (2 with unsuccessful ablation) had VT recurrence during follow‐up (39 months).ConclusionsEndo‐epicardial LP mapping allows us to identify the putative isthmuses of different VTs and effectively perform catheter ablation in patients with CCC and drug‐refractory VTs.

VT recurrence and predictors in patients with VT inducibility at the end of VT ablation

Abstract Background A successful Radiofrequency (RF) ablation of ventricular tachycardia (VT) can prevent VT recurrence. It has been reported that VT non-inducibility at the end of RF ablation is associated with less likely VT recurrence in ischemic cardiomyopathy (ICM) and non-ICM (NCIM). However, it is not clear whether we should use VT non-inducibility as routine end point in RF ablation of VT. Purpose The aim of this study was to evaluate VT recurrence in patients who couldn't be achieved VT non-inducibility at the end of RF ablation and the factors attributed to VT recurrence in ICM and NICM patients. Methods Between January 2009 and April 2020, 84 consecutive patients (ICM: 34, NICM: 50) underwent RF ablation for drug-resistant VT in our hospital. VT non-inducibility was defined as any ventricular tachy-arrhythmia, including clinical VT, non-clinical VT, and VF, was not induced by programed stimuli at the end of session. Non-inducibility was achieved in 37 patients but it was not achieved in 47 patients (ICM: 18, NICM: 29). To evaluate the validity of “non-inducibility” as an end point of VT ablation, 47 patients (male: 40, mean age: 66±15 years) in whom non-inducibility of any ventricular tachyarrhythmia was not achieved were studied. The primary endpoint was recurrence of any sustained VT and VF during follow up period (mean follow-up period was 1.4 (range, 0.0, 2.0) years.) Results Mean left ventricular ejection fraction (LVEF) was 36±13%. Epicardial ablation was required in 8 patients. 32 patients had electrical storm at the time of ablation. Among them, 21 patients had VT recurrence and 26 patients had non-VT recurrence during follow-up period. VT recurrence rate was significantly lower in patients with LVEF≥35% than those with LVEF&amp;lt;35% (HR=0.31, 95% CI 1.25–9.92). Multivariate survival analysis identified LVEF≥35% (HR=0.34, 95% CI 0.10–0.98) and ablation of VT isthmus (HR=0.18, 95% CI 0.02–0.78) as independent predictors of non-VT recurrence. Conclusions Even if non-inducibility of any ventricular tachyarrhythmia wasn't achieved at the end of ablation, the patients with LVEF≥35% or who had ablated of VT isthmus might prevent VT recurrence. The validity of non-inducibility of any ventricular tachyarrhythmia should be evaluated in each patient's background. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): Abbott, Medtronic

Catheter ablation of the left and right atrial appendages without isolation in persistent atrial fibrillation

Electrical isolation of the left atrial appendage (LAA) improves outcomes of patients with persistent atrial fibrillation (AF) but may increase the risk of thromboembolism. The purpose of this study was to describe a method to map and ablate appendage drivers without complete electrical isolation. One hundred thirteen patients underwent an ablation procedure for persistent AF. The procedure was performed during AF and consisted of pulmonary vein and posterior LA isolation as well as ablation of the LAA. The right atrium (RA) was targeted in patients with a right-to-left gradient in cycle length (CL). The end point of appendage ablation was CL slowing or AF termination but not complete isolation. Among the 113 patients (mean age 64.6 ± 8.6 years; ejection fraction 54% ± 13%; LA diameter 46 ± 6.5 mm), radiofrequency ablation terminated AF in 51 patients (45%). RA ablation was performed in 41 patients (36%) at the index or repeat procedure. The mean AF CL in the RA appendage (RAA) was shorter than that in the LAA (160 ± 32 ms vs 186 ± 29 ms; P < .01) in thesepatients. The most frequent target in the RA was the RAA (CLs approaching 50-60 ms). Discontinuing radiofrequency ablation upon AF termination or conduction slowing prevented LAA isolation. After a mean follow-up of 24 ± 15 months, 89 patients (78%) remained arrhythmia-free without antiarrhythmic medications. An ablation strategy guided by the AF CL addresses LAA drivers without complete electrical isolation and also helps identify the RAA as a source of persistent AF.

P347Physician-led, weight loss advice prior to atrial fibrillation ablation, overall weight change and clinical outcomes

Abstract Background Randomised trial, controlled study and international guidelines have advocated weight loss in AF patients with obesity as a means of attaining better AF burden control and maintenance of sinus rhythm. However, previous study required patients to undertake a highly structured weight management programme, detailed counselling, meal plans and behaviour modification. Aim To assess if weight-loss can be attained through a 5-minute, target-driven, physician-led counselling amongst overweight/obese patients referred AF ablation, without the need for intensive weight management programme. Subsequently to assess this can lead to better clinical outcomes (reduction in AF recurrence and readmission). Methods All patients referred for AF ablation in a tertiary centre over a 6-month period were included. Baseline weight and BMI at initial encounter plus weight and BMI at day of AF ablation were recorded. Optional physician-led counselling was provided, with aim for target weight loss of &amp;lt;10% or reduction of 3 point in BMI. Initial contact to AF ablation is 6 months. Clinical outcomes such as symptomatic AF &amp;gt;3 months post AF ablation and readmission for symptomatic AF were recorded. Follow-up duration of 6 months post ablation. Patients received counselling were designated Group 1, and those who did not were designated Group 2. Outcomes 146 new AF referrals for ablation seen over the 6-month period. 105 (71.9%) are paroxysmal AF, 37 (25.3%) are persistent, 4 permanent AF. Mean BMI 34.4 (+/- 5.1). Out of which, 76% have BMI &amp;gt; 30 (Obese), 47.6% possess BMI &amp;gt;35 (Morbidly obese), with 1 patient with BMI exceeding 50. 21.9% patients received physician-led counselling to lose weight. Basic demographics (age, gender), proportion of pAF and duration of AF, use of antiarrhythmic drugs were not statistically different between the two groups. Among AF patients receiving weight-loss counselling (Group 1), they have higher mean weight and BMI, 108kg (+/- 14.3) and BMI 33.7 (+/-4.3), as compared to those who did not received counselling (Group 2), 87.5kg (+/- 16.2) and BMI 29.5 (+/-4.3). At point of AF ablation, Group 1 has median weight loss of (-)4.5kg, mean reduction of BMI (-)2.0 points, while Group 2 has median weight gain of 3.6kg, increase of BMI 1.1 point. Overall statistically significant difference in weight change (p &amp;lt;0.001). Composite clinical outcomes at 6 months post ablation comprising recurrence of AF and readmission for symptomatic AF were higher in Group 2 as compared to Group 1, 38% vs 13% (p = 0.03). Summary This small cohort study suggests that concise physician-led weight loss counselling (without dietician-led meal plan or extensive weight loss programme) provided to AF patients with increased BMI can lead to significant weight loss and lower BMI in the run-up to AF ablation. This is also associated with statistically significant reduction in recurrence of AF and hospital re-admission.

Is ablation to atrial fibrillation termination of persistent atrial fibrillation the end point?: A systematic review and meta-analysis.

Background:The ideal ablation strategy and end point for persistent atrial fibrillation (AF) have not been well founded. Defining periprocedural AF termination as the end point of catheter ablation is still controversial. This meta-analysis aimed to analyze the differences between periprocedural AF termination and non-termination in the long-term AF recurrence rate and postoperative complications.Methods:Randomized controlled trials (RCTs) were identified by a systematic search of electronic databases including PubMed, EMBASE, and Cochrane library from January 2008 to August 2019. The primary outcome was freedom from AF or any atrial arrhythmia without antiarrhythmic drugs at the long-term (≥12 months) follow-up. The secondary outcome was overall postoperative complication rates. The risk ratio (RR) with 95% confidence interval (CI) was pooled for these outcomes. A forest plot, fixed-effects model or random-effect model, Q test, I2 statistic, and Egger funnel plot were used in the statistical analysis.Results:Fourteen RCTs were included in this meta-analysis. Overall, no significant difference was found in freedom from AF at the long-term follow-up between patients in whom AF termination was achieved and not achieved (RR = 0.93, 95% CI = 0.78-1.09, P = .36, I2 = 69%). Patients with AF non-termination had a lower complication occurrence rate than those with AF termination (RR = 1.74, 95% CI = 1.11-2.73, P = .02, I2 = 0%).Conclusion:Our meta-analysis suggests that AF termination is not a reliable procedural end point during ablation of persistent AF.

Feasibility, Safety, and Efficacy of Posterior Wall Isolation During Atrial Fibrillation Ablation: A Systematic Review and Meta-Analysis.

The posterior left atrium is an arrhythmogenic substrate that contributes to the initiation and maintenance of atrial fibrillation (AF); however, the feasibility, safety, and efficacy of posterior wall isolation (PWI) as an AF ablation strategy has not been widely reported. We undertook a systematic review and meta-analysis of studies performing PWI to assess (1) acute procedural success including the ability to achieve PWI and the number of procedure-related complications, (2) Long-term, clinical success including rates of arrhythmia recurrence and posterior wall reconnection, and (3) The efficacy of PWI compared with pulmonary vein isolation on preventing arrhythmia recurrence. MEDLINE, EMBASE, and Web of Science databases were searched in May 2018 to retrieve relevant studies. Results were pooled using a random effects model. Seventeen studies (13 box isolation, 3 single ring isolation, and 1 debulking ablation) comprising 1643 patients (31.3% paroxysmal AF, left atrial diameter 41±3.1 mm) were included in the final analysis. In studies focusing specifically on PWI, the acute procedural success rate for achieving PWI was 94.1% (95% CI, 87.2%-99.3%). Single-procedure 12-month freedom from atrial arrhythmia was 65.3% (95% CI, 57.7%-73.9%) overall and 61.9% (54.2%-70.8%) for persistent AF. Randomized control trials comparing PWI to pulmonary vein isolation (3 studies, 444 patients) yielded conflicting results and could not confirm an incremental benefit to PWI. Fifteen major complications (0.1%), including 2 atrio-esophageal fistulas, were reported. PWI as an end point of AF ablation can be achieved in a large proportion of cases with good rates of 12-month freedom from atrial arrhythmia. Although the procedure-related complication rate is low, it did not eliminate the risk of atrio-esophageal fistula. Registration: URL: http://www.crd.york.ac.uk/prospero. PROSPERO registration number: CRD42018107212.

Long-Term Clinical Comparison of Procedural End Points After Pulmonary Vein Isolation in Paroxysmal Atrial Fibrillation: Elimination of Nonpulmonary Vein Triggers Versus Noninducibility.

Pulmonary vein isolation (PVI) is effective for maintenance of sinus rhythm in 50% to 75% of patients with paroxysmal atrial fibrillation, and it is not uncommon for patients to require additional ablation after PVI. We prospectively evaluated the relative effectiveness of 2 post-PVI ablation strategies in paroxysmal atrial fibrillation. A total of 500 patients (mean age, 55.7±11.0 years; 74.6% male) were randomly assigned to undergo ablation by 2 different strategies after PVI: (1) elimination of non-PV triggers (group A, n=250) or (2) stepwise substrate modification including complex fractionated atrial electrogram or linear ablation until noninducibility of atrial tachyarrhythmia was achieved (group B, n=250). During a median follow-up of 26.0 months, 75 (32.2%) patients experienced at least 1 episode of recurrent atrial tachyarrhythmia after the single procedure in group A compared with 105 (43.8%) patients in group B (P value in log-rank test of Kaplan-Meier analysis: 0.012). Competing risk analysis showed that the cumulative incidence of atrial tachycardia was significantly higher in group B compared with group A (P=0.007). With the exception of total ablation time, there were no significant differences in fluoroscopic time or procedure-related complications between the 2 groups. Elimination of triggers as an end point of ablation in patients with paroxysmal atrial fibrillation decreased long-term recurrence of atrial tachyarrhythmia compared with a noninducibility approach achieved by additional empirical ablation. The post-PVI trigger test is thus a better end point of ablation for paroxysmal atrial fibrillation.

Thermophysical properties of Almahata Sitta meteorites (asteroid 2008 TC3) for high‐fidelity entry modeling

AbstractAsteroid 2008 TC3 was characterized in a unique manner prior to impacting Earth's atmosphere, making its October 7, 2008, impact a suitable field test for or validating the application of high‐fidelity re‐entry modeling to asteroid entry. The accurate modeling of the behavior of 2008 TC3 during its entry in Earth's atmosphere requires detailed information about the thermophysical properties of the asteroid's meteoritic materials at temperatures ranging from room temperature up to the point of ablation (T ~ 1400 K). Here, we present measurements of the thermophysical properties up to these temperatures (in a 1 atm. pressure of argon) for two samples of the Almahata Sitta meteorites from asteroid 2008 TC3: a thick flat‐faced ureilite suitably shaped for emissivity measurements and a thin flat‐faced EL6 enstatite chondrite suitable for diffusivity measurements. Heat capacity was determined from the elemental composition and density from a 3‐D laser scan of the sample. We find that the thermal conductivity of the enstatite chondrite material decreases more gradually as a function of temperature than expected, while the emissivity of the ureilitic material decreases at a rate of 9.5 × 10−5 K−1 above 770 K. The entry scenario is the result of the actual flight path being the boundary to the load the meteorite will be affected with when entering. An accurate heat load prediction depends on the thermophysical properties. Finally, based on these data, the breakup can be calculated accurately leading to a risk assessment for ground damage.

Long-Term Follow-Up After Catheter Ablation of Atrioventricular Nodal Reentrant Tachycardia in Children.

Catheter ablation of the slow conducting pathway (SP) is treatment of choice for atrioventricular nodal reentrant tachycardia (AVNRT). Although there are abundant data on AVNRT ablation in adult patients, little is known about the long-term results ≥3 years after AVNRT ablation in pediatric patients. Follow-up data from 241 patients aged ≤18 years who had undergone successful AVNRT ablation were analyzed. Median age at ablation had been 12.5 years, and median follow-up was 5.9 years. Radiofrequency current had been used in 168 patients (70%), whereas cryoenergy had been used in 73 patients (30%). Procedural end point of AVNRT ablation had been either SP ablation (no residual dual atrioventricular nodal physiology) or SP modulation (residual SP conduction allowing for a maximum of one atrial echo beat). After the initial AVNRT ablation, calculated freedom from AVNRT was 96% at 1 year, 94% at 3 years, 93% at 5 years, and 89% at 8 years. Age, sex, body weight, the choice of ablation energy, and the procedural end point of AVNRT ablation did not impact freedom from AVNRT. Six of 22 AVNRT recurrences (27%) occurred ≥5 years after ablation. No late complications including atrioventricular block were noted. Cumulatively, catheter ablation of AVNRT continued to be effective in >90% of our pediatric patients during the long-term course. A significant part of recurrences occurred >5 years post ablation. Body weight, energy source, and the end point of ablation had no impact on long-term results. No adverse sequelae were noted.

Magnetic phases in Pt/Co/Pt films induced by single and multiple femtosecond laser pulses

Ultrathin Pt/Co/Pt trilayers with initial in-plane magnetization were irradiated with femtosecond laser pulses. In this way, an irreversible structural modification was introduced, which resulted in the creation of numerous pulse fluence-dependent magnetic phases. This was particularly true with the out-of-plane magnetization state, which exhibited a submicrometer domain structure. This effect was studied in a broad range of pulse fluences up to the point of ablation of the metallic films. In addition to this single-pulse experiment, multiple exposure spots were also investigated, which exhibited an extended area of out-of-plane magnetization phases and a decreased damage threshold. Using a double exposure with partially overlapped spots, a two-dimensional diagram of the magnetic phases as a function of the two energy densities was built, which showed a strong inequality between the first and second incoming pulses.

Radiofrequency catheter ablation of ventricular tachycardia in structural heart disease: single team experience with follow-up upto 5 years

Introduction: Catheter ablation of ventricular tachycardia (VT) in structural heart disease has significantly evolved over the past few decades. We present our experience of VT ablation in such patients over last five years. Methods and Results: Out of 38 cases of VT ablation in patients with structural heart disease done during last five years, 18 had chronic myocardial scar, 2 had recent myocardial infarction, 1 dilated cardiomyopathy and 17 ARVD/C. Substrate modifications was performed as first step in majority of patients by using 3D electroanatomical system (NavX, St. Jude Medical, USA). VT induction was tried after substrate modification. End point of ablation was non-inducibility of all VTs. Failure of RFA was seen in no patient. Partial success of RFA was seen in 2 and in 36 (95%) the procedure was fully successful. Fifteen patients already had an ICD implanted whereas 20 patients underwent ICD implantation after the procedure. Median Follow-up available is for 38 months. Four patients had recurrence of VT identified by the ICD. No patient had sudden cardiac death. One patient of ARVD/C had progressive RV failure. Conclusion: VT ablation in patients with underlying structural heart disease significantly reduces the recurrence of VT episodes. It plays an important role in reducing the number of ICD therapies.

High-Speed, Integrated Ablation Cell and Dual Concentric Injector Plasma Torch for Laser Ablation-Inductively Coupled Plasma Mass Spectrometry.

In recent years, laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS) has gained increasing importance for biological analysis, where ultratrace imaging at micrometer resolution is required. However, while undoubtedly a valuable research tool, the washout times and sensitivity of current technology have restricted its routine and clinical application. Long periods between sampling points are required to maintain adequate spatial resolution. Additionally, temporal signal dispersion reduces the signal-to-noise ratio, which is a particular concern when analyzing discrete samples, such as individual particles or cells. This paper describes a novel, two-volume laser ablation cell and integrated ICP torch designed to minimize aerosol dispersion for fast, efficient sample transport. The holistic design utilizes a short, continuous diameter fused silica conduit, which extends from the point of ablation, through the ICP torch, and into the base of the plasma. This arrangement removes the requirement for a dispersive component for argon addition, and helps to keep the sample on axis with the ICP cone orifice. Hence, deposition of sample on the cones is theoretically reduced with a resulting improvement in the absolute sensitivity (counts per unit mole). The system described here achieved washouts of 1.5, 3.2, and 4.9 ms for NIST 612 glass, at full width half, 10%, and 1% maximum, respectively, with an 8-14-fold improvement in absolute sensitivity, compared to a single volume ablation cell. To illustrate the benefits of this performance, the system was applied to a contemporary bioanalytical challenge, specifically the analysis of individual biological cells, demonstrating similar improvements in performance.

Catheter ablation of ventricular tachycardia and mortality in patients with nonischemic dilated cardiomyopathy: can noninducibility after ablation be a predictor for reduced mortality?

Data on outcomes after catheter ablation of ventricular tachycardia (VT) in patients with nonischemic dilated cardiomyopathy (NIDCM) are insufficient. We aimed to investigate the effects of successful catheter ablation of VT on cardiac mortality in patients with NIDCM. One hundred two patients with NIDCM (86 men; mean age, 58.8±15.2 years; mean ejection fraction, 33.3±11.9%) underwent VT ablation. After catheter ablation, a programmed ventricular stimulation to test for success was performed. Complete VT noninducibility was achieved in 62 (61%) patients and partial success or failure in 32 (31%) patients. During 2 years of follow-up, VT recurrence was observed in 33 patients (53%) without inducible VTs and in 24 patients (75%) with inducible VT inducible (P=0.041). VT inducibility was associated with higher VT recurrence (adjusted hazard ratio, 1.84; 95% confidence interval, 1.08-3.13; P=0.025). The primary end point of all-cause mortality was reached in 9 patients (15%) with noninducible VTs versus 11 patients (34%) with inducible sustained VTs (P=0.026). VT inducibility was associated with all-cause mortality (adjusted hazard ratio, 2.73; 95% confidence interval, 1.003-7.43; P=0.049). In patients with NIDCM and recurrent sustained VTs, a complete ablation of all inducible VTs may be achieved in 60% of the cases. The complete noninducibility may be a preferable end point of ablation because it was associated with better long-term success. Importantly, if possible to achieve through ablation, a complete VT noninducibility was associated with reduction of the likelihood for all-cause mortality in patients with NIDCM.

Need for Ongoing Anti Arrhythmic Drugs After Ablation of Atrial Fibrillation. Review

Ablation of atrial fibrillation (AF) is increasingly common. Newer techniques have been developed and indications broadened to a greater number of patients with drug-resistant AF. The first end point of ablation is to cure AF without further need for Anti Arrhythmic Drugs (AADs), but the success rate at 1 year and over, after a single procedure, though higher than the success rate of AADs alone, is not 100% yet. The aim of the present work is to understand the added value of a persistent administration of previously ineffective AADs on the long-term success rate and to evaluate the timing of AADs suspension after ablation in different types of FA, when patients are in constant sinus rhythm after several months. The reduction of symptoms and the fear of asymptomatic recurrences of AF make physicians reluctant to discontinue AADs at the end of the blanking period, though the efficacy of AADs as a permanent solution late after procedure, to increase the sinus rhythm maintenance rate, is still a matter of ongoing debate. At the time, every patient undergoing ablation of AF should be assessed individually about the need to suspend AADs or not. To do this, good knowledge of AF recurrence predictors and long term success rates of AF ablation in specific clinical settings is essential. Loop Recorder as well is very useful in guiding the administration of AADs in a patient-tailored manner. Larger registries and controlled clinical trials in well-defined clinical settings are required to further elucidate the effects of a prolonged action of AADs after AF ablation. The article presented a short discussion of recent patents related to Anti Arrhythmic Drugs.

Efficient β-cell regeneration by a combination of neogenesis and replication following β-cell ablation and reversal of pancreatic duct ligation

Achieving efficient β-cell regeneration is a major goal of diabetes research. Previously, we found that a combination of β-cell ablation and pancreatic duct ligation led to β-cell regeneration by direct conversion from α-cells. Here, we studied the effect of surgical reversal of the duct ligation, finding that there was a wave of β-cell replication following reversal. The combination of β-cell neogenesis prior to reversal of the duct ligation and β-cell replication following reversal resulted in efficient β-cell regeneration and eventual recovery of function. This provides an important proof of principle that efficient β-cell regeneration is possible, even from a starting point of profound β-cell ablation. This has important implications for efforts to promote β-cell regeneration.