br Material and methods The study subjects
Material and methods The study subjects were 28 consecutive patients with organic phosphodiesterase inhibitor disease who underwent ICD implantation for the secondary prevention of sudden cardiac death, based on the indications for ICD implantation in the European Society of Cardiology׳s guidelines . The reason for ICD therapy in these patients was previously documented VF or hemodynamically unstable VT requiring electrical shock therapy. The exclusion criteria were the presence of atrial fibrillation, idiopathic VF (including Brugada syndrome), and acute coronary syndrome. Ischemic patients had a history of coronary intervention, including balloon angioplasty or stenting, and they were in stable condition at enrollment. An electrocardiogram was recorded (QRS duration and QTc intervals) and Holter monitoring (heart rate variability, heart rate turbulence, and TWA) was performed before ICD implantation. At the same time, blood samples were taken for measurement of B-type natriuretic peptide (BNP), left ventricular ejection fraction (LVEF) was assessed using echocardiography, and New York Heart Association functional class was determined based on the clinical history. During the follow-up period (10.2±6.2 months), ventricular tachyarrhythmias requiring appropriate shock therapy occurred in eight patients (29%). The subjects were divided into two groups based on whether appropriate shock therapy was required (n=8, Group A) or not (n=20, Group B). Parameters from echocardiography, electrocardiogram, and Holter monitoring were compared between the two groups, in order to investigate their relationship with the incidence of shock therapy after ICD implantation.
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Introduction Ventricular tachycardia (VT) originating from the epicardium is an important reason for failure of the endocardial ablation procedure . The percutaneous epicardial approach allows for VT ablation in many cases to be performed in the electrophysiology laboratory . Catheter ablation (CA) from the epicardium is often required for VT ablation of non-ischemic cardiomyopathy due to the presence of epicardial substrates. In a recent survey of 3 tertiary centers performing VT ablation from the epicardium, CA had a risk of 5% for acute and 2% for delayed major complications related to epicardial access . The risks associated with conventional pericardial access using conventional posterior puncture remain. Recently, a modified pericardial approach using anterior puncture has been reported, but the safety has not been systematically assessed .
Materials and methods
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Introduction An atrioventricular (AV) nodal (AVN) reentrant tachycardia (AVNRT) is one of the most common types of paroxysmal supraventricular tachycardias (PSVT), which can be treated by radiofrequency catheter ablation (RFA). Its underlying mechanism is believed to be the presence of antegrade dual AVN pathways (AVNPs) based on the longitudinal dissociation of the AV node, however, it remains controversial whether the reentrant circuit is confined to the compact AV node [1–3]. The main focus is on the issue of whether the upper final common pathway exists between the atrial myocardium and the AVNRT circuit, whereas from the observation of successful ablation sites, the anatomical relationship between the inferior nodal extension and the AVNRT circuit should be noteworthy. Our patient was a 49-year-old woman with a typical AVNRT confined to the compact AV node, showing presence of the subatrial upper and intranodal lower final common pathways in addition to numerous uncommon electrophysiological phenomena.
Case report Fig. 1 shows the surface 12-lead ECG recorded during a sinus rhythm with a cycle length (CL) of 920ms (A) and a clinical PSVT with a CL of 400ms (B). In panel B, the small negative waves immediately after the QRS in the inferior leads and the small positive wave immediately after the QRS in lead V1, indicated by arrows, indicate that the PSVT is very likely to be a typical AVNRT . An electrophysiological study (EPS) was performed using standard multielectrode catheters placed in the high right atrium (HRA), apex of the right ventricle (RV), His bundle region (HBE), and coronary sinus (CS) after obtaining written informed consent. Baseline electrophysiological parameters were as follows: sinus CL, atrio-His (AH) interval, His-ventricular interval, AV Wenckebach block CL, and ventriculo-atrial (VA) conduction block CL were 690, 70, 50, 375, and 500ms, respectively (not shown in the figure).