Pacing and clinical electrophysiology : PACE
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Pacing Clin Electrophysiol · Nov 2009
Clinical TrialTransesophageal electrophysiologic study to determine the inducibility after successful ablation of supraventricular tachycardia in children.
Radiofrequency ablation has become first-line therapy for supraventricular tachycardia in all age groups, but there has been a concern regarding the long-term effectiveness of the procedure in children. This study aimed to determine the inducibility after successful ablation of supraventricular tachycardia in children; assessment was performed using a transesophageal electrophysiologic study. ⋯ Radiofrequency ablation is a safe and effective method to manage children with supraventricular tachycardia, but patients must be observed for recurrence and new arrhythmias. Sustained tachycardia may also be induced in asymptomatic patients. A transesophageal electrophysiologic study is effective and safe for follow-up of radiofrequency ablation for assessment, diagnosis, and treatment of patients.
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Pacing Clin Electrophysiol · Sep 2009
A nonsense SCN5A mutation associated with Brugada-type electrocardiogram and intraventricular conduction defects.
Mutations of SCN5A, gene-encoding alpha-subunit of cardiac sodium channel, can cause mixed phenotypes of Brugada syndrome (BrS) and cardiac conduction diseases (CCD). We have identified a nucleotide change of SCN5A (4178T > G), which results in a nonsense mutation, L1393X, in a 36-year-old Caucasian man who presented with intraventricular conduction delays and BrS-type electrocardiogram change. To study biophysical characteristics of L1393X-SCN5A, electrophysiological and immuno-staining studies were performed using mammalian expression systems. ⋯ Voltage dependency of a steady-state activation and inactivation was not affected by the cotransfection of L1393X. Immuno-histochemical stainings demonstrated that L1393X proteins were expressed in the plasma membranes. Our study demonstrated that L1393X-SCN5A does not form functional channel proteins, which might account for the patient's mixed phenotypes of BrS and CCD.
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Pacing Clin Electrophysiol · Sep 2009
Case ReportsInitiation of ventricular tachycardia by interruption of pacemaker-mediated tachycardia in a patient with a dual-chamber implantable cardioverter defibrillator.
A 74-year-old man with a dual-chamber implantable cardioverter defibrillator implanted 3 years before experienced multiple ventricular tachycardias (VTs). All episodes were initiated by pacemaker-mediated tachycardia (PMT) that was either stopped by atrial undersensing or the tachycardia termination algorithm of the device. After the termination of PMT, two rapid ventricular paced beats, the first initiated by artificial triggering and the second due to retrograde conduction of the first one, initiated VT that was successfully terminated by antitachycardia pacing or a direct current shock of the device. All episodes revealed this pattern of initiation with a short-long-short ventricular sequence inducing VT.
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Pacing Clin Electrophysiol · Aug 2009
Multicenter StudyAtrial fibrillation significantly increases total mortality and stroke risk beyond that conveyed by the CHADS2 risk factors.
Atrial fibrillation (AF) is associated with an increased risk of mortality and stroke. However, it is unclear if AF is independently associated with these poor outcomes or it is merely a risk marker of other processes that convey the risk. ⋯ The CHADS2 score is a powerful predictor of stroke and death. AF increases the risk of these outcomes in an independent manner. These data support the concept that AF is a risk factor of future cardiovascular disease.