Project description:Radiofrequency (RF) ablation with irrigated tip catheters decreases the likelihood of thrombus and char formation and enables the creation of larger lesions. Due to the potential dramatic consequences, the prevention of thromboembolic events is of particular importance for left-sided procedures. Although acute success rates of ventricular tachycardia (VT) ablation are satisfactory, recurrence rate is high. Apart from the progress of the underlying disease, reconduction and the lack of effective transmural lesions play a major role for VT recurrences. This paper reviews principles of lesion formation with radiofrequency and the effect of tip irrigation as well as recent advances in new technology. Potential areas of further development of catheter technology might be the improvement of mapping by better substrate definition and resolution, the introduction of bipolar and multipolar ablation techniques into clinical routine, and the use of alternative sources of energy.
Project description:BackgroundCardiac involvement in Anderson-Fabry disease (AFD) can lead to arrhythmia, including ventricular tachycardia (VT). The literature on radiofrequency ablation (RFA) for the treatment of VT in AFD disease is limited.Case summaryWe discuss RFA of drug-refractory VT electrical storm in three males with AFD. The first patient (53 years old) had extensive involvement of the inferolateral left ventricle (LV) demonstrated with cardiac magnetic resonance imaging (CMRI), with a left ventricular ejection fraction (LVEF) of 35%. Two VT ablation procedures were performed. At the first procedure, the inferobasal endocardial LV was ablated. Furthermore, VT prompted a second ablation, where epicardial and endocardial sites were ablated. The acute arrhythmia burden was controlled but he died 4 months later despite appropriate implantable cardioverter-defibrillator therapies for VT. The second patient (67 years old) had full-thickness inferolateral involvement demonstrated with CMRI and LVEF of 45%. RFA of several endocardial left ventricular sites was performed. Over a 3-year follow-up, only brief non-sustained VT was identified, but he subsequently died of cardiac failure. Our third patient (69 years old), had an LVEF of 35%. He had RFA of endocardial left ventricular apical disease, but died 3 weeks later of cardiac failure.DiscussionRFA of drug-refractory VT in AFD is feasible using standard electrophysiological mapping and ablation techniques, although the added clinical benefit is of questionable value. VT storm in the context of AFD may be a marker of end-stage disease.
Project description:A 74-year-old woman presented with incessant wide complex tachycardia that was refractory to cardioversions. Successful radiofrequency catheter ablation was performed on the left ventricular posteromedial papillary muscle. An inaudible steam pop has occurred during the procedure, but we confirmed that there were no complications during the procedure and short-term follow-up of echocardiography. Two months after the procedure, an asymptomatic pseudoaneurysm was identified at the ablation site that had not been observed in the short-term follow-up.
Project description:Atrial tachycardia originating from the right atrial appendage has a higher probability of failure of catheter ablation. Here we report a case of a 13-year-old boy with incessant tachycardia, complicated by heart enlargement, and heart failure. Electrophysiological examination showed that atrial tachycardia (AT) originated from the apex of the right atrial appendage, and endocardial catheter ablation was ineffective. After thoracoscopic approach, the right atrial appendage was successfully ablated with bipolar radiofrequency ablation forceps, atrial tachycardia was terminated and sinus rhythm was restored. Within 3 months since the patient was discharged from the hospital, no arrhythmia occurred and the heart structure returned to normal. Thus, thoracoscopic clamp radiofrequency ablation may be a reasonable choice for young patients with atrial tachycardia originated from the right atrial appendage when transendocardial ablation is not effective.
Project description:BackgroundInterventricular septal perforation is an extremely rare complication of radiofrequency ablation (RFA), with an incidence of 1%. The most common mechanism is a 'steam pop', which can be described as 'mini-explosions' of gas bubbles. Data for percutaneous repair of cardiac perforations due to RFA are limited.Case summaryA 78-year-old female patient was referred to our department for the treatment of two iatrogenic ventricular septal defects (VSDs) following radiofrequency ablation (RFA) of premature ventricular contractions. One week post-ablation, chest pain and progressive dyspnoea occurred. Transthoracic echocardiography detected a VSD, diameter 10 mm. Hence, iatrogenic, RFA-related myocardial injury was considered the most likely cause of VSD, and the patient was referred to our tertiary care centre for surgical repair. Cardiovascular magnetic resonance (CMR) imaging demonstrated border-zone oedema of the VSD only and confirmed the absence of necrotic tissue boundaries, and the patient was deemed suitable for percutaneous device closure. Laevocardiography identified an additional, smaller muscular defect that cannot be explained by analysing the Carto-Map. Both defects could be successfully closed percutaneously using two Amplatzer VSD occluder devices.DiscussionIn conclusion, this case demonstrates a successful percutaneous closure of a VSD resulting from RFA using an Amplatzer septal occluder device. CMR might improve tissue characterization of the VSD borders and support the decision if to opt for interventional or surgical closure.
Project description:BACKGROUND:Recent advances have enabled noninvasive mapping of cardiac arrhythmias with electrocardiographic imaging and noninvasive delivery of precise ablative radiation with stereotactic body radiation therapy (SBRT). We combined these techniques to perform catheter-free, electrophysiology-guided, noninvasive cardiac radioablation for ventricular tachycardia. METHODS:We targeted arrhythmogenic scar regions by combining anatomical imaging with noninvasive electrocardiographic imaging during ventricular tachycardia that was induced by means of an implantable cardioverter-defibrillator (ICD). SBRT simulation, planning, and treatments were performed with the use of standard techniques. Patients were treated with a single fraction of 25 Gy while awake. Efficacy was assessed by counting episodes of ventricular tachycardia, as recorded by ICDs. Safety was assessed by means of serial cardiac and thoracic imaging. RESULTS:From April through November 2015, five patients with high-risk, refractory ventricular tachycardia underwent treatment. The mean noninvasive ablation time was 14 minutes (range, 11 to 18). During the 3 months before treatment, the patients had a combined history of 6577 episodes of ventricular tachycardia. During a 6-week postablation "blanking period" (when arrhythmias may occur owing to postablation inflammation), there were 680 episodes of ventricular tachycardia. After the 6-week blanking period, there were 4 episodes of ventricular tachycardia over the next 46 patient-months, for a reduction from baseline of 99.9%. A reduction in episodes of ventricular tachycardia occurred in all five patients. The mean left ventricular ejection fraction did not decrease with treatment. At 3 months, adjacent lung showed opacities consistent with mild inflammatory changes, which had resolved by 1 year. CONCLUSIONS:In five patients with refractory ventricular tachycardia, noninvasive treatment with electrophysiology-guided cardiac radioablation markedly reduced the burden of ventricular tachycardia. (Funded by Barnes-Jewish Hospital Foundation and others.).
Project description:Ventricular tachycardia is a common and lethal complication after myocardial infarction. Here we show that focal transfer of a gene encoding a dominant-negative version of the KCNH2 potassium channel (KCNH2-G628S) to the infarct scar border eliminated all ventricular arrhythmias in a porcine model. No proarrhythmia or other negative effects were discernable. Our results demonstrate the potential viability of gene therapy for ablation of ventricular arrhythmias.
Project description:Data on relative safety, efficacy, and role of different percutaneous left ventricular assist devices for hemodynamic support during the ventricular tachycardia (VT) ablation procedure are limited.We performed a multicenter, observational study from a prospective registry including all consecutive patients (N=66) undergoing VT ablation with a percutaneous left ventricular assist devices in 6 centers in the United States. Patients with intra-aortic balloon pump (IABP group; N=22) were compared with patients with either an Impella or a TandemHeart device (non-IABP group; N=44). There were no significant differences in the baseline characteristics between both the groups. In non-IABP group (1) more patients could undergo entrainment/activation mapping (82% versus 59%; P=0.046), (2) more number of unstable VTs could be mapped and ablated per patient (1.05±0.78 versus 0.32±0.48; P<0.001), (3) more number of VTs could be terminated by ablation (1.59±1.0 versus 0.91±0.81; P=0.007), and (4) fewer VTs were terminated with rescue shocks (1.9±2.2 versus 3.0±1.5; P=0.049) when compared with IABP group. Complications of the procedure trended to be more in the non-IABP group when compared with those in the IABP group (32% versus 14%; P=0.143). Intermediate term outcomes (mortality and VT recurrence) during 12±5-month follow-up were not different between both groups. Left ventricular ejection fraction ?15% was a strong and independent predictor of in-hospital mortality (53% versus 4%; P<0.001).Impella and TandemHeart use in VT ablation facilitates extensive activation mapping of several unstable VTs and requires fewer rescue shocks during the procedure when compared with using IABP.
Project description:BackgroundAtrial tachycardia (AT) can be treated by medical or electrical cardioversion but the recurrence rate is high. Three-dimensional electro-anatomical mapping, recently described in horses, might be used to map AT to identify a focal source or reentry mechanism and to guide treatment by radiofrequency ablation.ObjectivesTo describe the feasibility of 3D electro-anatomical mapping and radiofrequency catheter ablation to characterize and treat sustained AT in horses.AnimalsNine horses with sustained AT.MethodsRecords from horses with sustained AT referred for radiofrequency ablation at Ghent University were reviewed.ResultsThe AT was drug resistant in 4 out of 9 horses. In 8 out of 9 horses, AT originated from a localized macro-reentrant circuit (n = 5) or a focal source (n = 3) located at the transition between the right atrium and the caudal vena cava. In these 8 horses, local radiofrequency catheter ablation resulted in the termination of AT. At follow-up, 6 out of 8 horses remained free of recurrence.Conclusions and clinical importanceDifferentiation between focal and macro-reentrant AT in horses is possible using 3D electro-anatomical mapping. In this study, the source of right atrial AT in horses was safely treated by radiofrequency catheter ablation.
Project description:OBJECTIVES:This study sought to characterize ventricular tachycardia (VT) ablation outcomes across nonischemic cardiomyopathy (NICM) etiologies and adjust these outcomes by patient-related comorbidities that could explain differences in arrhythmia recurrence rates. BACKGROUND:Outcomes of catheter ablation of VT in patients with NICM could be related to etiology of NICM. METHODS:Data from 2,075 patients with structural heart disease referred for catheter ablation of VT from 12 international centers was retrospectively analyzed. Patient characteristics and outcomes were noted for the 6 most common NICM etiologies. Multivariable Cox proportional hazards modeling was used to adjust for potential confounders. RESULTS:Of 780 NICM patients (57 ± 14 years of age, 18% women, left ventricular ejection fraction 37 ± 13%), underlying prevalence was 66% for dilated idiopathic cardiomyopathy (DICM), 13% for arrhythmogenic right ventricular cardiomyopathy (ARVC), 6% for valvular cardiomyopathy, 6% for myocarditis, 4% for hypertrophic cardiomyopathy, and 3% for sarcoidosis. One-year freedom from VT was 69%, and freedom from VT, heart transplantation, and death was 62%. On unadjusted competing risk analysis, VT ablation in ARVC demonstrated superior VT-free survival (82%) versus DICM (p ? 0.01). Valvular cardiomyopathy had the poorest unadjusted VT-free survival, at 47% (p < 0.01). After adjusting for comorbidities, including age, heart failure severity, ejection fraction, prior ablation, and antiarrhythmic medication use, myocarditis, ARVC, and DICM demonstrated similar outcomes, whereas hypertrophic cardiomyopathy, valvular cardiomyopathy, and sarcoidosis had the highest risk of VT recurrence. CONCLUSIONS:Catheter ablation of VT in NICM is effective. Etiology of NICM is a significant predictor of outcomes, with ARVC, myocarditis, and DICM having similar but superior outcomes to hypertrophic cardiomyopathy, valvular cardiomyopathy, and sarcoidosis, after adjusting for potential covariates.