Journal of cardiovascular electrophysiology
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J. Cardiovasc. Electrophysiol. · May 2000
Comparative StudyDependence of electrogram duration in right posteroseptal atrium and atrium-pulmonary vein junction on pacing site: mechanism and implications regarding atrioventricular nodal reentrant tachycardia and paroxysmal atrial fibrillation.
The fractionated atrial electrogram, a signal helpful in identifying the target site for radiofrequency catheter ablation of the slow AV nodal pathway, is considered to arise from nonuniform anisotropic electrical activity. However, the effects of pacing sites and radiofrequency ablation on these electrograms are not clear. Similarly, the nature of the fractionated atrial electrogram in the atrium-pulmonary vein junction has yet to be determined. ⋯ These findings suggest that the fractionated atrial electrograms in the right posteroseptal atrium and ostium of left or right superior pulmonary veins are potentially consistent with nonuniform anisotropic propagation. Alternations of electrogram characteristics after successful radiofrequency ablation of the slow AV nodal pathway may arise from the changes of nonuniform anisotropic activity in the right posteroseptal atrium.
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J. Cardiovasc. Electrophysiol. · May 2000
Comparative StudySpatial and temporal heterogeneity of depolarization and repolarization may complicate implantable cardioverter defibrillator therapy in Brugada syndrome.
Dynamic variations in electrophysiologic phenomena inherent to the Brugada syndrome may complicate therapy with implantable cardioverter defibrillators (ICDs). ⋯ These findings demonstrate that, in Brugada syndrome, spontaneous or ajmaline-induced changes in the surface ECG may be paralleled by significant variations in the right ventricular endocardial electrogram that may result in ICD malfunction. Implantation of a left ventricular epicardial lead for sensing and pacing may be the ultimate successful approach in certain patients. To assure proper ICD function, ajmaline testing during ICD implantation appears to be helpful.
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J. Cardiovasc. Electrophysiol. · Jan 2000
Mapping and radiofrequency catheter ablation of the three types of sustained monomorphic ventricular tachycardia in nonischemic heart disease.
Sustained monomorphic ventricular tachycardia (VT) associated with nonischemic cardiomyopathy (CMP) is uncommon. Optimal approaches to catheter mapping and ablation are not well characterized, but they are likely to depend on the VT mechanism. The purpose of this study was to evaluate the mechanisms of sustained monomorphic VT encountered in nonischemic CMP and to assess the feasibility, safety, and efficacy of catheter radiofrequency ablation for treatment. ⋯ Three different mechanisms of VT are encountered in patients with nonischemic CMP. The mapping and ablation approach varies with the type of VT. In this selected population, the overall efficacy was 77%.
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J. Cardiovasc. Electrophysiol. · Jan 2000
Catheter ablation for hemodynamically unstable monomorphic ventricular tachycardia.
Hemodynamic collapse precludes extensive catheter mapping to identify focal target regions in many patients with ventricular tachycardia (VT) associated with heart disease. This study tested the feasibility of catheter ablation of poorly tolerated VTs by targeting a region identified during sinus rhythm. ⋯ Ablation of poorly tolerated VT is feasible in some patients by mapping during sinus rhythm and performing ablation over a region of identifiable scar that contains abnormal conduction and a presumptive VT exit.
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J. Cardiovasc. Electrophysiol. · Jan 2000
Case ReportsVentricular fibrillation in a patient with prominent J (Osborn) waves and ST segment elevation in the inferior electrocardiographic leads: a Brugada syndrome variant?
Recurrent ventricular fibrillation was observed in a 29-year-old Vietnamese man who did not exhibit structural heart disease. The patient's ECG showed prominent J (Osborn) waves and ST segment elevation in the inferior leads that were not associated with hypothermia, serum electrolyte disturbance, or myocardial ischemia. Rate-dependent change in the amplitude of J waves and ST segment elevation also were observed. ⋯ Adjunctive treatment with amiodarone reduced J wave amplitude, preventing ventricular fibrillation and ICD shocks. Prominent J waves and ST segment elevation in the inferior leads may serve as an important diagnostic sign to detect high-risk individuals with a history of unexplained syncope. ICD implantation plus amiodarone is the treatment of choice.