Project description:BackgroundRadiofrequency (RF) ablation of typical atrioventricular nodal reentrant tachycardia (tAVNRT) is performed without revealing out the location of antegrade slow pathway (ASp). In this study, we studied a new electrophysiological method of identifying the site of ASp.MethodsThis study included 19 patients. Repeated series of very high-output single extrastimulations (VhoSESts) were delivered at the anatomical slow pathway region during tAVNRT. Tachycardia cycle length (TCL), coupling interval (CI), and return cycle (RC) were measured and the prematurity of VhoSESts [ΔPM (= TCL - CI)] and the prolongation of RCs [ΔPL (= RC - TCL)] were calculated. Pacing sites were classified into two categories: (i) ASp capture sites [DSPC(+) sites], where two different RCs were shown, and ASp non-capture sites [DSPC(-) sites], where only one RC was shown. RF ablation was performed at DSPC(+) sites and/or sites with catheter-induced mechanical trauma (CIMT) to ASp.ResultsDSPC(+) sites were shown in 13 patients (68%). RF ablation was successful in all patients without any degree of atrioventricular block nor recurrence. Total number of RF applications was 1.8 ± 1.1. Minimal distance between successful ablation sites and DSPC(+)/CIMT sites and His bundle (HB) electrogram recording sites was 1.9 ± 0.8 mm and 19.8 ± 6.1 mm, respectively. ΔPL of more than 92.5 ms, ΔPL/TCL of more than 0.286, and ΔPL/ΔPM of more than 1.565 could identify ASp with sensitivity of 100%, 91.1%, and 88.9% and specificity of 92.9%, 97.0%, and 97.6%, respectively.ConclusionsSites with ASp capture and CIMT were close to successful ablation sites and could be useful indicators of tAVNRT ablation.
Project description:In vivo description of ventricular tachycardia (VT) circuits is limited by insufficient spatiotemporal resolution. We used a novel high-resolution mapping technology to characterize the electrophysiological properties of the postinfarction reentrant VT circuit.In 15 swine, myocardial infarction was induced by left anterior descending artery balloon occlusion. Animals were studied 6 to 8 weeks after myocardial infarction. Activation mapping of VTs was performed by using the Rhythmia mapping system. Activation time was based on a combination of bipolar and unipolar electrograms. The response to overdrive pacing from different zones of the circuit was examined.A total of 56 monomorphic VTs were induced (3.8±2.1 per animal). Among these, 21 (37.5%) were hemodynamically stable and allowed mapping of the circuit. Isthmuses were 16.4±7.2 mm long and 7.4±2.8 mm wide. Conduction velocities were slowest at the inward curvature into the isthmus entrance (0.28±0.2 m/s), slightly faster at the outward curvature exit (0.40±0.3 m/s) and nearly normal at the central isthmus (0.62±0.2 m/s). In 3 animals, 2 VT morphologies with opposite axes sharing the same isthmus were mapped. Conduction velocities within the shared isthmus were dependent on the activation vector, consistently slower at the proximal curvature. Overdrive pacing from isthmus sites determined by activation mapping was consistent with entrainment criteria for isthmus. However, dimensions of the isthmus defined by entrainment exceeded dimensions of the isthmus measured by activation mapping by 32±18%.In postinfarction reentrant VT, conduction velocities are slowest at the proximal and distal curvatures. Entrainment mapping overestimates the true size of the isthmus. High-resolution activation mapping of VT may better guide ablation therapy.
Project description:Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common type of supraventricular tachycardia. Slow pathway (SP) ablation is the treatment of choice with a high acute success rate and a negligible periprocedural risk. However, long-term outcome data are scarce. The aim of this study was to assess long-term outcome and arrhythmia free survival after SP ablation. In this study, 534 consecutive patients with AVNRT, who underwent SP ablation between 1994 and 1999 were included. During a mean follow-up of 15.5 years, 101 (18.9%) patients died unrelated to the procedure or any arrhythmia. Data were collected by completing a questionnaire and/or contacting patients. Clinical information was obtained from 329 patients (61.6%) who constitute the final study cohort. During the electrophysiological study, sustained 1:1 slow AV nodal pathway conduction was eliminated in all patients. Recurrence of AVNRT was documented in 9 patients (2.7%), among those 7 patients underwent a successful repeat ablation procedure. New-onset atrial fibrillation (AF) was documented in 39 patients (11.9%) during follow-up. Pre-existing arterial hypertension (odds ratio 2.61, 95% CI 1.14-5.97, p?=?0.023), age (odds ratio 1.05, 95% CI 1.02-1.09, p?=?0.003) and the postinterventional AH interval (odds ratio 1.02, 95% CI 1.00-1.04, p?=?0.038) predicted the occurrence of AF. The present long-term observational study after successful SP ablation of AVNRT confirms its clinical value reflected by low recurrence and complication rates. The unexpectedly high incidence of new-onset AF (11.9%) may impact long-term follow-up and requires further clinical attention.
Project description:BackgroundAtrioventricular nodal reentrant tachycardia (AVNRT) is a common supraventricular arrhythmia that is frequently encountered in an otherwise healthy patient population. Recent guidelines of the European Society of Cardiology underline the role of catheter ablation in the long-term management of these patients.Case summaryThis case describes the clinical presentation and treatment options in a patient with typical slow/fast AVNRT, the most common subform of AVNRT, where antegrade conduction occurs over the slow pathway and retrograde conduction over the fast pathway. The ablation strategy in these patients is illustrated based on intracardiac recordings in combination with per-procedural three-dimensional imaging.DiscussionAtrioventricular nodal reentrant tachycardia is a common arrhythmia with good prognosis but significant impact on quality of life of affected patients. Catheter ablation should be considered early as it can be performed safely and with a very high success rate.
Project description:Background Catheter-based slow-pathway modification (SPM) is the treatment of choice for symptomatic atrioventricular nodal reentrant tachycardia (AVNRT). We sought to investigate the interactions between patient age and procedural outcomes in pediatric patients undergoing catheter-based SPM for AVNRT. Methods and Results A retrospective cohort study was performed, including consecutive patients undergoing acutely successful SPM for AVNRT from 2008 to 2017. Those with congenital heart disease, cardiomyopathy, and accessory pathways were excluded. Patients were stratified by age quartile at time of SPM. The primary outcome was AVNRT recurrence. A total of 512 patients underwent successful SPM for AVNRT. Age quartile 1 had 129 patients with a median age and weight of 8.9 years and 30.6 kg, respectively. Radiofrequency energy was used in 98% of cases. Follow-up was available in 447 (87%) patients with a median duration of 0.8 years (interquartile range, 0.2-2.5 years). AVNRT recurred in 22 patients. Multivariable Cox proportional hazard modeling identified atypical AVNRT (hazard ratio [HR], 5.83; 95% CI, 2.01-16.96; P=0.001), dual atrioventricular nodal only (HR, 4.09; 95% CI, 1.39-12.02; P=0.011), total radiofrequency lesions (HR, 1.06 per lesion; 95% CI, 1.01-1.12; P=0.032), and the use of a long sheath (HR, 3.52; 95% CI, 1.23-10.03; P=0.010) as predictors of AVNRT recurrence; quartile 1 patients were not at higher risk of recurrence (HR, 0.45; 95% CI, 0.10-1.97; P=0.29). Complete heart block requiring permanent pacing occurred in one quartile 2 patient at 14.9 years of age. Conclusions Pediatric AVNRT can be treated with radiofrequency-SPM with high procedural efficacy and minimal risk of complications, including heart block. Atypical AVNRT and dual atrioventricular nodal physiology without inducible tachycardia remain challenging substrates.
Project description:RationaleDual atrioventricular node non-reentrant tachycardia (DAVNNRT) is a rare arrhythmia. We present a case of inappropriate implantable cardioverter defibrillator (ICD) therapy caused by DAVNNRT. DAVNNRT is easily misdiagnosed as atrial fibrillation and is often identified as ventricular tachycardia (VT) by the supraventricular tachycardia-ventricular tachycardia (SVT-VT) discriminator of the ICD.Patient concernsA 73-year-old man with ischemic heart disease (IHD) presented with palpitations accompanied by dyspnea and syncope. Frequent multifocal premature ventricular beats and non-sustained ventricular tachycardia were observed on ambulatory electrocardiography. The left ventricular ejection fraction decreased to 32%.DiagnosisHe was diagnosed with IHD, heart failure with reduced ejection fraction (HFrEF), and VT.Interventions: Initially, the patient received a single-chamber ICD implantation for secondary prevention of sudden death. He then suffered from inappropriate anti-tachycardia pacing (ATP)/shock therapy many times after the procedure. DAVNNRT was confirmed in an electrophysiology study (EPS), and radiofrequency ablation of the slow pathway successfully terminated this tachycardia.OutcomesNo episode of inappropriate ICD therapy or tachycardia occurred during the follow-up.LessonsIn conclusion, it is essential to have a full understanding of DAVNNRT and eliminate slow pathways for patients with DAVNNRT and be prepared to implant an ICD.
Project description:Atrioventricular (AV)-nodal-reentrant-tachycardia is a rare association in a patient with persistent left-sided superior vena cava and dilated coronary sinus. There are a few inherent difficulties in ablation in this condition, viz., difficulty in localization of good site for ablation and difficulty in stabilization of the ablation catheter at the designated site, making it difficult to produce transmural lesions and increasing risk of producing AV block. We hereby present a case highlighting the difficulties and possible solutions for them.
Project description:A patient presented with symptoms of palpitations. Her standard 12-lead electrocardiogram captured 3 potential causes of her symptoms (premature atrial contractions, junctional rhythm, and narrow complex tachycardia). Further workup uncovered dual atrioventricular node physiology with 1:2 sinus conduction and resultant alternating QRS from a slow and fast conduction pathway. (Level of Difficulty: Intermediate.) Central Illustration