ABSTRACT
BACKGROUND: Implantable cardioverter-defibrillators (ICDs) can terminate some ventricular tachycardias (VTs) painlessly with antitachycardia pacing (ATP). ATP has not routinely been applied for VT >188 bpm because of concerns about efficacy, risk of acceleration, and delay of definitive shock therapy. This prospective, multicenter study evaluated the efficacy of empirical ATP to terminate fast VT (FVT; >188 bpm). METHODS AND RESULTS: Two hundred twenty coronary artery disease patients received ICDs for standard indications. Empirical, standardized therapy was programmed so that all FVT episodes (average cycle length [CL] 240 to 320 ms, 250 to 188 bpm) were treated with 2 ATP sequences (8-pulse burst pacing train at 88% of the FVT CL) before shock delivery. A total of 1100 episodes of spontaneous ventricular tachyarrhythmias occurred during a mean of 6.9+/-3.6 months of follow-up. Fifty-seven percent were classified as slow VT (CL>/=320 ms), 40% as FVT (240 ms=CL<320 ms), and 3% as ventricular fibrillation (CL<240 ms). A total of 446 FVT episodes, mean CL=301+/-24 ms, occurred in 52 patients (median 2 episodes per patient). ATP terminated 396 FVT episodes (89%), with an adjusted efficacy of 77% (95% CI 68% to 83%). VT acceleration caused by ATP occurred in 10 FVT episodes (4%). FVT arrhythmic syncope occurred on 9 occasions (2%) in 4 patients. CONCLUSIONS: FVT (CL<320 ms) is common in ICD patients. ATP can terminate 3 of 4 of these episodes with a low incidence of acceleration and syncope. ATP for FVT may safely reduce the morbidity of painful shocks.
Subject(s)
Cardiac Pacing, Artificial/methods , Coronary Disease/complications , Electric Countershock/methods , Tachycardia, Ventricular/complications , Tachycardia, Ventricular/therapy , Adult , Aged , Aged, 80 and over , Anti-Arrhythmia Agents/therapeutic use , Defibrillators, Implantable/standards , Electric Countershock/instrumentation , Female , Humans , Male , Middle Aged , Monitoring, Ambulatory/instrumentation , Survival Rate , Tachycardia, Ventricular/physiopathology , Treatment OutcomeABSTRACT
Atrial fibrillation is the most common cardiac arrhythmia requiring treatment. Limitations of medical treatment have prompted development of nonpharmacologic therapies for this arrhythmia. These are aimed at ventricular rate control during atrial fibrillation, termination of the arrhythmia, and/or prevention of recurrences. Ventricular rate control can be achieved with transcatheter ablation or modification of the atrioventricular node. The MAZE operation is effective in preventing arrhythmia recurrence, but because it requires cardiac surgery, its appeal is limited. Development of the technique for direct transcatheter ablation of atrial fibrillation is eagerly anticipated and may represent the standard curative treatment of the future. In appropriately selected patients, implantable device therapy may play an important role in the treatment of paroxysmal atrial fibrillation.
Subject(s)
Atrial Fibrillation/therapy , Anti-Arrhythmia Agents/therapeutic use , Atrial Fibrillation/drug therapy , Atrial Fibrillation/prevention & control , Atrial Fibrillation/surgery , Atrioventricular Node/surgery , Cardiac Pacing, Artificial , Catheter Ablation/methods , Defibrillators, Implantable , Electric Countershock , Forecasting , Heart Rate , Humans , Recurrence , Ventricular FunctionABSTRACT
The recent identification of the sequences of the peptides derived from a number of human melanoma-associated antigens has presented opportunities for developing a specific-peptide-based vaccine in this form of cancer. Since antigen-presenting cells (APC) play a crucial role in the induction of the T-cell-mediated immune response, we examined whether or not ex vivo cultured APC, bearing the appropriate MHC restricting elements, when pulsed with a relevant melanoma-specific cytotoxic-T-lymphocyte (CTL)-determined peptide, can present the peptide to the CTL. Here we show that a population of cells, derived from the monocyte/macrophage lineage from peripheral blood and grown in granulocyte/macrophage-colony-stimulating factor, exhibit many essential characteristics of "professional" APC (dendritic-type morphology with a proportion of the population, the B7 molecule, and high levels of MHC class I and class II molecules, CD11b and CD54 molecules) and are capable of efficiently presenting the nonapeptide, EADPTGHSY, encoded by the melanoma antigen MAGE-1 gene, to the MAGE-1-specific CTL clone, 82/30. These results suggest that this type of autologous ex vivo cultured population of professional APC, when pulsed with the relevant-CTL-determined peptide, can serve as a novel type of candidate vaccine for active specific immunization against HLA-A1-positive patients with melanoma expressing the MAGE-1 antigen.