Direct Current Ablation Research Articles

Inflammation and long-term outcomes after first-time direct current cardioversion for atrial fibrillation: a nationwide register study

Abstract Background Emerging evidence suggests that the pathogenesis of atrial fibrillation (AF) is affected by inflammatory processes which contribute to structural and electrical remodeling of the atria, creating a substrate for arrythmia. Aim To assess whether inflammation measured by C-reactive protein (CRP) is associated with readmission for direct current (DC) cardioversion, ablation, heart failure or stroke after discharge from 1st time DC cardioversion. Methods This nationwide retrospective cohort study included patients undergoing 1st DC cardioversion between 2011 and 2018. Exclusion criteria were death within one day of cardioversion and no available CRP at baseline. Primary outcome was readmission for DC cardioversion of AF. Secondary outcomes were AF ablation, new admission of stroke, new admission of heart failure (HF), and all-cause death. Absolute risk rates (ARR) of outcomes were calculated for patients with available 1-year follow-up data. CRP 20 mg/L was chosen as cutoff to establish a clinically relevant borderline for inflammation. The association between baseline CRP and outcome was assessed in Cox proportional hazards regression models with a follow-up period starting from 1st DC cardioversion, ending no later than 31st of December 2018, for the entire study population (n=9,977). Results After exclusion criteria the study population consisted of 9,977 patients Mean age for CRP > 20mg/L: 66.8 (IQR: 60.5-74.2). Mean age for CRP < 20mg/L 68.9 (IQR: 62.9-75.9)(p<0.001). In total, 68.9% were male and the most frequent comorbidities included hypertension (57.3%), ischemic heart disease (25.1%), HF (20.6%), and history of stroke (7.1%). Patients with available CRP measurement and 1yr follow up was 7,764. Compared to patients with low CRP (<20 mg/L), patients with elevated CRP (>20mg/L) had a higher 1-year ARR of HF, and all cause death (p<0.001). Compared to patients with low CRP, patients with elevated CRP had a lower 1-year ARR of all-ablation and new DC cardioversion (p<0.001), (Table 1). CRP > 20mg/L was associated with lower risk for new DC cardioversion (HR 0.72, 95% CI: 0.64-0.82, p<0.001). However, in patients <75 years of age with CRP > 20mg/L at baseline had an increased risk of stroke after multivariable adjustments (HR 1.92, 95% CI: 1.10-3.35; p = 0.02) (Fig.1), while CRP > 20 mg/L was not associated with an increased risk of stroke in patients > 75yrs of age (Cox regressions estimates) (p for interaction = 0.03). Conclusion However, elevated CRP was associated with an increased risk of stroke in patients <75 years of age, even after multivariable adjustments. These results suggest that CRP may not be a reliable predictor of readmission for DC-cardioversion, especially in older individuals, but might be a potential risk stratification tool in identifying AF patients at higher risk of stroke in young individuals. We suspect this is due to the population with elevated CRP has more comorbidities and are older.

Historical developments in the diagnosis and treatment of pre-excitation syndromes (WPW)

In 1930, Wolff, Parkinson and White described the syndrome that bears their names. The mechanisms of supraventricular tachycardias were analyzed by brilliant electrocardiography interpretation by Pick and Langendorf. Wellens and Durrer using electrophysiologic studies analyzed the tachycardia mechanism invasively. In Germany the group by Seipel and Breithardt as well as Neuss and Schlepper studied the tachycardia mechanisms and response to antiarrhythmic drugs invasively by electrophysiological studies. Following the first successful interruption of an accessory pathway by Sealy in 1967, surgeons and electrophysiologists cooperated in Germany. Two centers, Hannover and Düsseldorf were established. Direct current (DC) ablation of accessory pathways was introduced by Morady and Scheinman. Because of side effects induced by barotrauma of DC, alternative strategies were studied. In 1987, radiofrequency ablation was introduced and thereafter established as curative therapy of accessory pathways in all locations.

Short history of the DC-Catheter-Ablation

Direct current (DC) catheter ablation in 5patients aiming to interrupt rapid atrioventricular (AV) conduction with atrial fibrillation and subsequent pacemaker implantation was first published by M.M.Scheinman etal. (San Francisco, CA, USA) in 1982. In Germany, L.Seipel, G.Breithardt, and M.Borggrefe reported their first experience with DC catheter ablation in 1984, followed by the group in Bonn (M.Manz and B.Lüderitz) in 1985. The first international DC catheter ablation registry, which also included four German centers, reported DC catheter ablation results of 127 patients in 24centers in 1984. Complete AV block was achieved in 71% patients. In 1992, the Hannover group (H‑J.Trappe, H.Klein and J.Huang) reported results of DC catheter ablation of AV conduction performed between 1983 and 1990 in 100 patients (86% with rapid atrial fibrillation, 14% with AV-node reentry tachycardias). The first successful DC catheter ablation in apatient with Wolff-Parkinson-White (WPW) syndrome was reported in 1985 by F.Morady etal. (San Francisco, CA, USA). In 1987, M.Borggrefe etal. were the first to report aswitch from DC catheter ablation to ahigh-frequency (HF) catheter ablation procedure in apatient with WPW syndrome. The use of DC catheter ablation to treat ventricular tachycardia (VT) was described by G.O.Hartzler (Kansas City, MO, USA) in 3patients in 1983. M.Borggrefe etal. (1989) reported on 24patients who underwent DC catheter ablation for VT. Of those, 17patients did not have VT recurrence within the following 14months. In 1994, the Hannover group (H-JTrappe, H.Klein) published their 5‑year long-term results of DC catheter ablation of VT in 51patients. VT recurrence occurred in 57% patients and overall mortality was also high (16%). Acomparison of DC catheter ablation with HF catheter ablation for recurrent VT was reported in 1994 by G.Gonska etal. (Göttingen, Germany). After 2years follow-up, success rates were not found to be significantly different.

Surgical ablation of long-standing persistent atrial fibrillation: 1-year outcomes from the CArdioSurgEry Atrial Fibrillation (CASE-AF) registry.

The CArdioSurgEry Atrial Fibrillation (CASE-AF) registry is a prospective, multicentre study for collecting and analysing real-world data of surgical atrial fibrillation (AF) treatment. This study aimed to evaluate outcomes of surgery for long-standing persistent AF at 1 year. In total, 17 centres consecutively include all eligible patients with continuous AF lasting for ≥1 year. Exclusion criteria are missing informed consent or age <18 years. For patient-reported outcomes measures, the European Heart Rhythm Association score was used. No presence of AF (based on ECG findings including Holter ECG and/or implanted devices), no re-ablation, no further cardioversion and no rehospitalization due to AF after a 3-month blanking period defined no AF recurrence at 1 year. From January 2017 to January 2020, a total of 1115 patients were enrolled in CASE-AF. Of them, 202 patients (mean age 69.7 ± 7.8 years, 27.2% female) underwent surgical ablation of long-standing persistent AF (study cohort), mostly accompanied by left atrial appendage closure (n = 180 [89%], resection n = 75 [42%]) and predominantly performed as concomitant (n = 174 [86%]) and left atrial only procedure (n = 144 [71%]). Early mortality (30 days) was 2.0% and morbidity was low. At follow-up (median 14.4 months, interquartile range, 12.7-17.6 months, 100% complete), 106 patients (56%) had no AF recurrence and 93% of them were asymptomatic. AF recurrence was accompanied by AF-related rehospitalization (n = 12, P = 0.003), direct current shock cardioversion (n = 23, P < 0.001), AF ablation (n = 7, P = 0.003) and stroke (n = 3, P = 0.059). Multivariable analysis identified cryoablation, predominantly performed endocardially including additional left atrial (74%) and biatrial (42%) lesions, as a significant factor for freedom from AF recurrence (odds ratio 2.7, 95% confidence interval 1.07-6.79, P = 0.035). According to CASE-AF, surgical ablation of long-standing persistent AF is most effective when concomitantly performed using endocardial cryoablation. Ongoing follow-up allows further elucidation of efficacious treatment strategies.

A method for selective stimulation of leg chemoreceptors in whole crustaceans.

The integration of sensory information with adequate motor outputs is critical for animal survival. Here, we present an innovative technique based on a non-invasive closed-circuit device consisting of a perfusion/stimulation chamber chronically applied on a single leg of the crayfish Procambarus clarkii. Using this technique, we focally stimulated the leg inside the chamber and studied the leg-dependent sensory-motor integration involving other sensory appendages, such as antennules and maxillipeds, which remain unstimulated outside the chamber. Results show that the stimulation of a single leg with chemicals, such as disaccharides, is sufficient to trigger a complex search behaviour involving locomotion coupled with the reflex activation of antennules and maxillipeds. This technique can be easily adapted to other decapods and/or other sensory appendages. Thus, it has opened possibilities for studying sensory-motor integration evoked by leg stimulation in whole aquatic animals under natural conditions to complement, with a direct approach, current ablation or silencing techniques.

Diagnosis and cure of supraventricular tachycardia

The seminal work of Dr Mel Scheinman marked the onset of the era of catheter ablation, a major advance in the management of patients with various arrhythmias.1 In the early 1980s, direct current (DC) shocks were initially used to create third-degree atrioventricular (AV) block in patients with atrial fibrillation and an uncontrolled ventricular rate or drug-refractory AV nodal reentrant tachycardia associated with severe symptoms. Targets for DC ablation gradually expanded to include posteroseptal accessory pathways (APs) and ventricular tachycardia, both idiopathic and postinfarction.

Decreased left atrial appendage emptying velocity as a link between atrial fibrillation type, heart failure and older age and the risk of left atrial thrombus in atrial fibrillation.

Decreased left atrial appendage emptying velocity (LAAV) is a known predictor of LAA thrombus in atrial fibrillation (AF). The aim of our study was to identify which of the clinical risk factors for LAA thrombus are associated with decreased LAAV. The study included 1476 consecutive AF patients who underwent transesophageal echocardiography (TEE) before AF direct current cardioversion or ablation in two high-reference cardiology departments. Patients were divided into two groups: 71 (4.8%) patients with LAAV < 20 cm/s and 1405 patients (95%) with LAAV ≥ 20 cm/s. Compared with patients with LAAV ≥ 20 cm/s, those with decreased LAAV were older, more often had non-paroxysmal AF, were burdened with more concomitant diseases (including hypertension, diabetes, vascular disease, and heart failure [HF]) with higher median CHA2 DS2 -VASc score (3 [2-4] vs 2 [1-3], P < .0001), and had lower glomerular filtration rate (GFR). Prevalence of LAA thrombus was higher in patients with decreased LAAV compared with those with LAAV ≥ 20cm/s (20% vs 4.6%, P < .0001). In patients with decreased LAAV, there was no difference in the frequency of LAA thrombus between those treated with VKA and those receiving NOAC, while in patients with LAAV ≥ 20 cm/s a trend was observed towards a benefit with NOAC. In multivariate logistic regression, non-paroxysmal AF, HF and age ≥ 65 years predicted both LAAV < 20 cm/s and LAA thrombus, while GFR < 60 mL/min/1.73 m2 predicted only the presence of LAA thrombus. One in five AF patients with decreased LAAV had LAA thrombus, regardless of the type of OAC. Non-paroxysmal AF, HF and age ≥ 65 years might increase LAA thrombus risk via reduced LAAV.

A SYSTEMATIC REVIEW OF RECENT ADVANCES OF AGNIKARMA IN THE MANAGEMENT OF HAEMORRHOID

Background and purpose: Haemorrhoid means an abnormal mass of dilated and engorged blood vessel in swollen tissue that occurs internally in the anal canal or externally around the anus. Haemorrhoid is an extremely common problem reported since thousands of years with a prevalence rate that is highest among all the anorectal disorders. Haemorrhoid resembles with arsha in ayurveda. The disease arsha (piles) is initiated with agnimandya (Improper digestion) due to improper food habits and lifestyles. Agnikarma has been explained by Sushruta as one among the Anushastras having greater importance in the management of arsha. The purpose of the study to explain the importance of agnikarma as parasurgical procedure in non surgical management of arsha. Material & Methods: Different samhitas,classical texts and modern texts are well scrutinized to study the recent advances of agnikarma in arsha. Result: All the modern techniques of cauterizations are indirectly based on agnikarma. Discussion: In modern management different laser technique are used such as infrared coagulation , Bipolar cautery, direct current and radiofrequency ablation therapy and BEIM technology. Conclusion: Agnikarma in the management of arsha is widely used with recent advances. Sushruta is the pioneer of Agnikarma. Keywords: Agni Karma, Anushastras,Cautery.

In vitro analysis of the origin and characteristics of gaseous microemboli during catheter electroporation ablation.

Recent studies demonstrated that irreversible electroporation (IRE) ablation may be an alternative method for thermal ablation for pulmonary vein isolation. Development of gaseous microemboli during catheter ablation might lead to asymptomatic ischemic events and is therefore an important research topic. Gas formation during arcing with direct current catheter ablation has been studied in the past, however not for nonarcing IRE-ablation. The aim of the present study was to visualize, quantify, and characterize gas formation during nonarcing millisecond IRE-pulses using a multielectrode circular catheter. In vitro, gas formation during IRE-pulses was studied using a high-speed imaging, direct volume measurements, and a bubble counter. Gas formation was compared between cathodal and anodal IRE-pulses and between a small and large catheter hoop diameter. High-speed images showed the location and dynamics of gas formation during cathodal and anodal millisecond IRE-pulses. The direct volume measurements demonstrated a significantly larger volume for cathodal than for anodal IRE-pulses (P < .001), and no significant difference between small and large hoop diameters. A strong linear relationship was found between delivered charge and total gas volume (r = 0.99). Bubble counter measurements showed that cathodal IRE-pulses produced more and larger gas bubbles than anodal IRE-pulses. The ratio of total gas volume between cathodal and anodal IRE-pulses is different as predicted from electrolysis theory. In vitro, millisecond anodal IRE-pulses produce significantly less and smaller gas bubbles than millisecond cathodal IRE-pulses. In vivo experiments are required to investigate the clinical implication of these observations.

Arrhythmic Burden and Outcomes in Pulmonary Arterial Hypertension.

Pulmonary arterial hypertension (PAH) is a devastating, life-limiting disease driven by small vessel vascular remodeling leading to a rise in pulmonary vascular resistance (PVR). Patients present with a range of symptoms including shortness of breath, exercise intolerance, palpitations or syncope. Symptoms may be related to vascular disease progression or arrhythmia secondary to the adaptation of the right heart to pressure overload. Arrhythmic burden is high in patients with left heart disease and guideline-based treatment of arrhythmias improves quality of life and prognosis. In PAH the incidence and prevalence of arrhythmias is less well-defined and there are no PAH-specific guidelines for arrhythmia management. We undertook a literature search identifying 13 relevant papers; detection of arrhythmias was acquired from 12-lead electrocardiogram (ECG) or Holter monitors. In all forms of pulmonary hypertension (PH) the prevalence of supraventricular arrhythmias (SVA) was 26–31%, ventricular arrhythmias (VA) 24% and a 5-year incidence of SVA ~13.2–25.1%. Prevalence and incidence of arrhythmias in PAH is less clear due to limited study numbers and the heterogenous nature of the patient population studied. For arrhythmia treatment, only single-arm studies of therapeutic strategies were reported using antiarrhythmic drugs (AAD), direct current cardioversion (DCCV) and ablation. Periods between ECG or Holter have not been investigated, highlighting the possibility that significant arrhythmias may be undetected. Advances in monitoring allow long-term surveillance via implanted/non-invasive monitors. Use of such technologies may provide an accurate estimate of incidence and prevalence of arrhythmias in patients with PAH, further defining relationships to adverse outcomes, and therapeutic options.

Intrapulmonary Vein Ablation Without Stenosis: A Novel Balloon‐Based Direct Current Electroporation Approach

BackgroundCurrent thermal ablation methods for atrial fibrillation, including radiofrequency and cryoablation, have a suboptimal success rate. To avoid pulmonary vein (PV) stenosis, ablation is performed outside of the PV, despite the importance of triggers inside the vein. We previously reported on the acute effects of a novel direct current electroporation approach with a balloon catheter to create lesions inside the PVs in addition to the antrum. In this study, we aimed to determine whether the effects created by this nonthermal ablation method were associated with irreversible lesions and whether PV stenosis or other adverse effects occurred after a survival period.Methods and ResultsInitial and survival studies were performed in 5 canines. At the initial study, the balloon catheter was inflated to contact the antrum and interior of the PV. Direct current energy was delivered between 2 electrodes on the catheter in ECG‐gated 100 μs pulses. A total of 10 PVs were treated demonstrating significant acute local electrogram diminution (mean amplitude decrease of 61.2±19.8%). After the survival period (mean 27 days), computed tomography imaging showed no PV stenosis. On histologic evaluation, transmural, although not circumferential, lesions were seen in each treated vein. No PV stenosis or esophageal injury was present.ConclusionsIrreversible, transmural lesions can be created inside the PV without evidence of stenosis after a 27‐day survival period using this balloon‐based direct current ablation approach. These early data show promise for an ablation approach that could directly treat PV triggers in addition to traditional PV antrum ablation.

Urgent Direct Current Cardioversion or Ablation for Atrial Fibrillation or Atrial Flutter and Acute Decompensated Heart Failure

Background: Guidelines recommend initial rate control in haemodynamically stable patients with atrial fibrillation (AF) or atrial flutter (AFL) and acute decompensated heart failure (ADHF). However, patients with persistent tachycardia or worsening heart failure despite medical therapy may require restoration of sinus rhythm. There are limited data on urgent rhythm control. We investigated the outcomes of patients managed with urgent direct current cardioversion (DCCV) or ablation.

Abstract 60: Inducible Arrythmogenicity of Direct Current Electroporation Ablation: Insight from a Series of Acute Canine Studies

Background: The use of direct current electroporation has the potential for significant utility because of its non-thermal approach to tissue destruction. However, the fear of inducibility of cardiac arrhythmias (particular ventricular fibrillation) when using electroporation remains of concern due to membrane poration and ion flux during periods of vulnerability occurring in ventricular repolarization. Objectives: Critically examine the incidence of arrhythmias in a series of acute canine studies to retrospectively determine cause and safe electoporative dosing margins. Methods: We performed electroporation ablation in 6 acute canine studies. These were experimental studies performed at sites critical in arrhytmogenesis. Sites included the pulmonary veins, left atrial appendage, superior vena cavae, right atrium and ventricle. Electroporation was delivered using an ECG gating algorithm so that QRS complexes are tagged and direct current energy is not delivered during the vulnerable portion of the T wave. Results: In 6 acute canine experiments, we delivered a total of 62 electroporation applications for ablation purposes. The average electroporation dosage delivered involved an average of 1427 Volts (range 750-3000 V), Pulse length of 100 ms, and number of pulses of 20.2 (range 10-100). AF was induced in 27.4% of electroporiatve applications. Atrial flutter/tachycardia occurred in 8.1%. VF occurred in only one application at a location of the left superior pulmonary vein. Conclusion: These data suggest that induction of VF is relatively uncommon with ECG gating and highlight its importance when using this modality. However, the induction of AF occurs with higher frequency. The actual mechanism as to why this occurs requires further systematic study.

Ten-year outcomes of monomorphic ventricular tachycardia catheter ablation in repaired tetralogy of Fallot

Monomorphic ventricular tachycardia (MVT) is common in adults with repaired tetralogy of Fallot (TOF), and is associated with sudden cardiac death. Management of MVT is not defined, and results of catheter ablation (CA) are limited. To evaluate long-term outcomes of MVT CA in repaired TOF. Thirty-four patients (mean age 32±10.3 years; 59% male) with repaired TOF underwent CA for symptomatic MVT between 1990 and 2012 in our centre; direct-current ablation (DCA) was used in 6%, radiofrequency followed by DCA in 29% and radiofrequency alone in 65%. Right ventricular (RV) dysfunction was present in 35% and left ventricular (LV) dysfunction in 21%. Mean numbers of clinical and induced MVTs were 1 and 2, respectively. Mean VT rate was 225±95bpm. Ablation targeted a single site (range 1-2), which was RV outflow tract in 85%. Primary success, defined as ventricular tachycardia (VT) termination during CA and final non-inducibility, was obtained in 82%. Seven patients (21%) required redo ablation in the first 3 months (before 2004; DCA). No death related to CA occurred. Mean follow-up time was 9.5±5.2 years. Antiarrhythmic therapy was discontinued in 71%. There were two cases of sudden cardiac death and four VT recurrences. Freedom from death and arrhythmia recurrence was 94% at 5 years, 81% at 10 years and 70% at 20 years. Global survival was 91% at 20 years. Baseline LV ejection fraction<60% was significantly associated with ventricular arrhythmia recurrence (hazard ratio 16.4, 95% confidence interval 1.8-147; P=0.01). CA can safely address macroreentrant MVT in repaired TOF patients with an acceptable long-term rate of recurrence in this high-risk population. Anatomical classification of isthmuses with electroanatomical mapping provides reproducible endpoints for CA. Attention should be given to LV systolic function in risk assessment and selection of candidates for implantable cardioverter-defibrillator.

Increased levels of red cell distribution width is correlated with presence of left atrial stasis in patients with non-valvular atrial fibrillation.

OBJECTIVE:Red cell distribution width (RDW) and neutrophil to lymphocyte ratio (NLR) have been found to be associated with non-valvular atrial fibrillation (AF) and cardiovascular diseases. However, correlation of these parameters with presence of left atrial (LA) thrombus and/or spontaneous echo contrast (SEC) in patients with non-valvular AF has not been clarified. This study was an investigation of correlation of RDW, NLR, and clinical risk factors with LA thrombus and dense SEC in patients with non-valvular AF in the Turkish population.METHODS:The demographic, laboratory, and echocardiographic properties of 619 non-valvular AF patients who underwent transesophageal echocardiography (TEE) examination before direct current cardioversion (DCCV) or AF ablation treatment were retrospectively investigated. Complete blood count (CBC) and biochemical parameters were studied 6 to 12 hours before TEE examination. Left atrial stasis (LAS) markers were noted as presence of left atrial/left atrial appendage (LA/LAA) thrombus or dense spontaneous echo contrast (DSEC).RESULTS:Total of 325 (52%) patients with LAS were compared with 294 patients (48%) without LAS. In the LAS group, there were 274 (84%) patients with LA/LAA thrombus and 51 (16%) patients with DSEC. LAS (+) group, values for RDW (14.85±1.48 vs. 13.77±1.30; p<0.01), NLR (2.38 [1.58], vs. 2.10 [1.35]; p<0.01) and C-reactive protein (0.95 [0.61] vs. 0.88 [0.60] mg/L; p<0.01) were significantly higher than seen in LAS (-) group. In multivariate regression analysis, increased level of RDW, age, male gender, heart failure, duration of AF >6 months, and international normalized ratio <2 were independently correlated with presence of LAS.CONCLUSION:Our study indicated that increased level of RDW is independently correlated with higher risk for development of LAS in patients with non-valvular AF.

Novel Percutaneous Epicardial Autonomic Modulation in the Canine for Atrial Fibrillation: Results of an Efficacy and Safety Study

Endocardial ablation of atrial ganglionated plexi (GP) has been described for treatment of atrial fibrillation (AF). Our objective in this study was to develop percutaneous epicardial GP ablation in a canine model using novel energy sources and catheters. Phase 1: The efficacy of several modalities to ablate the GP was tested in an open chest canine model (n = 10). Phase 2: Percutaneous epicardial ablation of GP was done in six dogs using the most efficacious modality identified in phase 1 using two novel catheters. Phase 1: Direct current (DC) in varying doses (blocking [7-12 μA], electroporation [300-500 μA], ablation [3,000-7,500 μA]), radiofrequency ablation (25-50 W), ultrasound (1.5 MHz), and alcohol (2-5 mL) injection were successful at 0/8, 4/12, 5/7, 3/8, 1/5, and 5/7 GP sites. DC (500-5,000 μA) along with alcohol irrigation was tested in phase 2. Phase 2: Percutaneous epicardial ablation of the right atrium, oblique sinus, vein of Marshall, and transverse sinus GP was successful in 5/6 dogs. One dog died of ventricular fibrillation during DC ablation at 5,000 μA. Programmed stimulation induced AF in six dogs, preablation and no atrial arrhythmia in three, flutter in one, and AF in one postablation. Heart rate, blood pressure, effective atrial refractory period, and local atrial electrogram amplitude did not change significantly postablation. Microscopic examination showed elimination of GP, and minimal injury to atrial myocardium. Percutaneous epicardial ablation of GP using DC and novel catheters is safe and feasible and may be used as an adjunct to pulmonary vein isolation in the treatment of AF in order to minimize additional atrial myocardial ablation.

Electroporation (Revival of Direct Current Ablation)

Several different techniques and energy sources have been developed for catheter ablation of tachyarrhythmias, including atrial fibrillation and ventricular tachycardia.1–3 Radiofrequency (RF) current is the most commonly used energy source for ablation. Although RF ablation has been proven to be effective, there are several limitations, including relatively long procedure times and high recurrence rate, especially for ablation of atrial fibrillation and ventricular tachycardia.2,3 During RF ablation, excessive tissue heating may lead to serious complications, such as steam pop, cardiac perforation, pulmonary vein stenosis, coronary arterial injury, and thrombo-embolism.1–4 Conversely, tissue cooling by arterial flow (providing greater heat sink) may limit RF lesion formation and lead to gaps in the ablation line, such as linear ablation across the mitral isthmus.5,6 Article see p 913 Direct current (DC) catheter ablation technique was initiated in early 1980s, but was abandoned shortly after RF ablation became available in 1990s.7 DC ablation was associated with serious complications, supposedly related to barotrauma and proarrhymia.8,9 Barotrauma is caused by a high-pressure shock wave resulting from an electrically isolating vapor globe, leading to arcing (spark) and explosion.8 At the …

Good outcomes with low-energy direct current prostate ablation

Good outcomes with low-energy direct current prostate ablation

Prediction of Long‐Term Outcomes of Catheter Ablation of Persistent Atrial Fibrillation by Parameters of Preablation DC Cardioversion

It has been demonstrated that atrial fibrillation (AF) frequently recurred after cardioversion (CV) using direct current (DC) or radiofrequency catheter ablation (RFCA) in patients with persistent (PeAF) or longstanding persistent AF (LPAF). We hypothesized that the atrial substrate impeding successful CV would also produce difficulty in catheter ablation, and therefore, the outcomes of RFCA for PeAF and LPAF could be predicted by the parameters determined at the time of DC CV. From 2006 to 2009, 94 patients with PeAF and LPAF who had undergone elective DC CV before RFCA were studied. The parameters associated with DC CV, including number of shocks, cumulative energy adjusted, highest energy adjusted, with or without intravenous amiodarone use, and other clinical parameters were assessed. Thirty-two out of the 94 patients (34%) experienced AF recurrence during the follow-up of 19.8 ± 12.3 months after RFCA. The average time to recurrence of AF after RFCA was 9.2 ± 3.2 months. Of the 62 patients, 29 patients (31%) remained sinus rhythm (SR) without antiarrhythmic drug (AAD). The patients who maintained SR had smaller body mass index (BMI) (P = 0.048), shorter duration of AF (P = 0.012), and lower prevalence of diabetes mellitus (P = 0.023) compared with patients in whom AF recurred. Total number of shocks, total energy, and highest shock energy during CV were lower (P < 0.001, P = 0.002, P = 0.048, respectively) in patients with SR during the follow-up. The outcome in patients who used amiodarone IV prior to CV, however, was not different from that in those who did not use amiodarone IV. DC energy parameters for successful CV before RFCA were useful to predict the long-term outcome after RFCA in patients with PeAF and LPAF. The presence of the atrial substrate making DC CV difficult might reflect atrial substrate that subsequently related to the recurrence of AF after RFCA in chronic AF. These DC energy parameters may be related to the chronicity or electroanatomical remodeling of AF.

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