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Brugada syndrome (BrS) is a cardiac electrophysiological disease with unknown etiology, associated with sudden cardiac death. Symptomatic patients are treated with implanted cardiac defibrillator, but no risk stratification strategy is effective in patients that are at low to medium arrhythmic risk. Cardiac computational modeling is an emerging tool that can be used to verify the hypotheses of pathogenesis and inspire new risk stratification strategies. However, to obtain reliable results computational models must be validated with consistent experimental data. We reviewed the main electrophysiological and structural variables from BrS clinical studies to assess which data could be used to validate a computational approach. Activation delay in the epicardial right ventricular outflow tract is a consistent finding, as well as increased fibrosis and subclinical alterations of right ventricular functional and morphological parameters. The comparison between other electrophysiological variables is hindered by methodological differences between studies, which we commented. We conclude by presenting a recent theory unifying electrophysiological and structural substrate in BrS and illustrate how computational modeling could help translation to risk stratification. [ABSTRACT FROM AUTHOR]

A case study of a 71‐year‐old woman who is diagnosed with Atrioventricular nodal reentry tachycardia (AVNRT) is presented. It reports that the retrograde depolarization of the His bundle (HB) by the ventricular stimulus eliminated the long‐short activation sequence in the HB. It also mentions that the injection of adenosine triphosphate (ATP), and atrial and ventricular entrainment during the tachycardia were not attempted owing to the poor inducibility of the sustained tachycardia.

Introduction: The incidence of pacemaker-mediated tachycardia (PMT) varies as a function of patient characteristics, device programming and algorithm specificities. We investigated the efficacy of the Boston Scientific algorithm by reviewing PMT episodes in a large device population.Methods: In this multicenter study, we included 328 patients implanted with a Boston Scientific device: 157 non-dependent patients with RYTHMIQ™ activated (RYTHMIQ group), 76 patients with permanent AV-conduction disorder (AV-block group) and 95 Cardiac Resynchronization Therapy patients (CRT group). For each patient, we reviewed the last 10 remote monitoring-transmitted EGMs diagnosed as PMT.Results: We analyzed 784 PMT episodes across 118 patients. In the RYTHMIQ group, the diagnosis of PMT was correct in most episodes (80%) of which 69% was directly related to the prolongation of the AV-delay associated with the RYTHMIQ algorithm. The usual triggers for PMT were also observed (PVC 16%, PAC 9%). The remainder of the episodes (20%) in RYTHMIQ patients and most episodes of AV-block (66%) and CRT patients (74%) were incorrectly diagnosed as PMT during sinus tachycardia at the maximal tracking rate. The inappropriate intervention of the algorithm during exercise causes non-conducted P-waves, loss of CRT (sustained in six patients) and may have been pro-arrhythmogenic in one patient (induction of ventricular tachycardia).Conclusion: Algorithms to minimize ventricular pacing can occasionally have unintended consequences such as PMT. The PMT algorithm in Boston Scientific devices is associated with a high rate of incorrect PMT diagnosis during exercise resulting in inappropriate therapy with non-conducted P-waves, loss of CRT and limited risk of pro-arrhythmic events. [ABSTRACT FROM AUTHOR]

The article offers a commentary on a study on atrial fibrillation (AF) frequency mapping using continuous wavelet transform (CWT). Topics covered include the need to determine the substrate responsible for AF specific to individual patient for a more targeted ablative therapy, costs associated with mapping techniques using basket-type catheter and non-invasive body surface electrodes, and the utility of CWT frequency analysis versus fast-Fourier transform (FFT)-derived dominant frequency (DF).

The article presents a case study of a 49-year-old man with hypertension who revealed an irregular heart rhythm during preoperative evaluation for kidney stone. The Echocardiogram examination showed mild left ventricular dysfunction while the coronary angiogram revealed nonobstructive coronary artery disease. The study involved two basic mechanisms including 1:2 AV conduction and His extrasystole.

The article presents a case study wherein a 62-year-old woman with history of hypertension, diabetes and end-stage renal disease documented wide QRS tachycardia with a right bundle branch block (RBBB) and no response to calcium channel blocker therapy. Topics include cardiac catheterization underwent by the patient, electrophysiology study and mapping and surface electrocardiography (ECG) during sinus rhythm. The patient's electrograms are presented.

The article presents a study on the termination of atrial fibrillation during ablation. It notes the long-term success rate of sinus rhythm from 10% to 30% is serial cardioversions are combined with antiarrhythmic medications due to the unrelenting pathophysiology of atrial fibrillation. It also discusses the critical importance of pulmonary vein isolation for the treatment of persistent atrial fibrillation with antral pulmonary vein isolation and targeting of nonpulmonary triggers.

The article presents a case study of a patient with supraventricular tachycardia whose tracing showing four surface electrocardiogram (ECG) demonstrates a ventricular extrastimulus delivered from the right ventricular base. Further diagnostic maneuvers of the patient excluded the presence of an accessory atrioventricular (AV) connection. The article discusses importance of correct catheter positioning prior to the commencement of programmed electrical stimulation.