Pacing and clinical electrophysiology : PACE
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Pacing Clin Electrophysiol · Jul 2004
Radiofrequency catheter ablation for arrhythmic storm in patients with an implantable cardioverter defibrillator.
The aim of the study was to analyze the usefulness of RFA in controlling arrhythmic storm due to hemodynamically stable VT in a cohort of patients with an ICD and to evaluate the incidence of arrhythmic storm among patients with an ICD. A group of 13 (3%) of 403 consecutive ICD recipients were submitted to RFA of VT during an arrhythmic storm. Two additional patients were referred from other institutions. ⋯ During a mean follow-up of 12 +/- 17 months, only two patients suffered a single episode of VT. Arrhythmic storm requiring VT ablation was uncommon among patients with an ICD and occurred late after ICD implantation. The arrhythmic episode was successfully controlled in the majority of patients with endocardial or epicardial RFA.
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Pacing Clin Electrophysiol · Jul 2004
Comparative StudySurgical open-chest ventricular defibrillation: triphasic waveforms are superior to biphasic waveforms.
Triphasic shocks have been evaluated for endocardial defibrillation but not for open-chest epicardial defibrillation. The purpose of this study was to compare the efficacy and safety of biphasic versus triphasic shocks for epicardial defibrillation in a porcine model. Twenty-two adult swine (18-28 kg) were deeply anesthetized and intubated. ⋯ In group 2 (small paddle electrodes), triphasic shocks yielded a significantly higher percentage of shock success than biphasic shocks at the energy levels of 5, 10, and 20 J). Shock induced ventricular tachycardia was similar for both waveforms; asystole was rare. For open-chest defibrillation, triphasic waveform shocks were superior to biphasic waveform shocks for VF termination at energy levels of 3-20 J and were as safe as biphasic shocks.
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Pacing Clin Electrophysiol · Jul 2004
High incidence of appropriate and inappropriate ICD therapies in children and adolescents with implantable cardioverter defibrillator.
Appropriate and inappropriate therapies of implantable cardioverter defibrillators have a major impact on morbidity and quality of life in ICD recipients, but have not been systematically studied in children and young adults during long-term follow-up. ICD implantation was performed in 20 patients at the mean age of 16 +/- 6 years, 11 of which had prior surgical repair of a congenital heart defect, 9 patients had other cardiac diseases. Implant indications were aborted sudden cardiac death in six patients, recurrent ventricular tachycardia in 9 patient, and syncope in 5 patients. ⋯ There is a high rate of ICD therapies in young ICD recipients, the majority of which occur during early follow-up. The rate of inappropriate therapies is as high as 47% and is caused by supraventricular tachycardia and electrode complications in the majority of cases. Prospective trials are required to establish preventative strategies of ICD therapies in this young patient population.
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Pacing Clin Electrophysiol · Jul 2004
Endocardial atrial pacing lead implantation and midterm follow-up in young patients with sinus node dysfunction after the fontan procedure.
The purpose of the study was to investigate the results of endocardial lead implantation, lead performance, and follow-up in young patients after the Fontan procedure. A retrospective study was conducted with patients who had endocardial atrial pacing for SND and intact AVN function after Fontan from two pediatric centers. Patient demographics, pacing, and sensing data of endocardial atrial leads were analyzed at the time of pacemaker implantation and follow-up visits. ⋯ Anticoagulation therapy (aspirin n = 5, warfarin n = 8) was continued by 13 patients. Complications consisted of a pneumothorax at implantation and a transient ischemic attack in one patient 4 years after pacemaker implant. Endocardial atrial leads offer low energy thresholds and can be implanted relatively safely in Fontan patients.
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Pacing Clin Electrophysiol · Jun 2004
Differences between study-specific and subject-specific heart rate corrections of the QT interval in investigations of drug induced QTc prolongation.
A computational study was designed to investigate the differences between the so-called study-specific and subject-specific heart rate corrections of QT interval. In 53 healthy subjects (25 women, mean age 26.7 +/- 8.7 years), serial 10-second electrocardiograms (ECG) were obtained during daytime hours. In each subject, 200 ECGs were selected representative of the individual QT/RR relationship. ⋯ The subject-specific corrections led to maximum errors in single milliseconds (error range of 2.4, 5.7, and 2.6 ms with linear, log/log linear, and exponential models, respectively) while the study-specific corrections led to substantially greater errors (error range of 17.8, 19.4, and 16.9 ms with linear, log/log linear, and exponential models, respectively). Both Bazett and Fridericia corrections led not only to substantial errors (error range of 28.3 and 16.9 ms) but also to regular bias with systematically false negative and false positive conclusions dependent on modeled heart rate acceleration and deceleration. Thus, subjects-specific corrections should be used in the intensive and definite studies aimed at providing the final answer on the ability of a drug to prolong the QT interval.