ABSTRACT
BACKGROUND: Commercially available implantable defibrillators utilize a high-tilt waveform. Studies in atrial fibrillation and transthoracic defibrillation of ventricular fibrillation (VF) have shown improved defibrillation efficacy using low-tilt (LT) waveforms. We investigated the feasibility, efficacy, and safety of a LT waveform in the transvenous defibrillation of VF and hypothesized that it would be more efficacious than standard tilted biphasic (STB) waveforms. METHODS AND RESULTS: The investigation was performed in four phases in a porcine model: an efficacy study of LT monophasic waveforms (n = 9), an efficacy study of LT biphasic waveforms (n = 9), a comparison study between the most successful LT waveforms and clinically available STB waveforms (n = 15), and a safety study (n = 9). A total of 1,056 shocks were delivered (phase 1: 288, phase 2: 288, phase 3: 480). The LT biphasic 8/4-ms waveform was significantly more likely to successfully defibrillate than the LT monophasic and STB waveforms with an odds ratio of 122.3 (95% confidence interval: 32.5, 460.2, P < 0.001). The calculated defibrillation threshold (E50) for the LT 8/4-ms waveform was 12.7 J compared to 43.5 J and 45.5 J for STB waveforms 6/6 ms and 8/4 ms, respectively, and 47.7 J for LT 12-ms waveform. The LT 8/4-ms waveform had no lasting detrimental effect on cardiac function, and any transient hemodynamical or biochemical changes observed were comparable to those observed with STB waveforms. CONCLUSION: LT waveforms are effective and appear safe in transvenous defibrillation in a porcine model of VF. The LT biphasic 8/4-ms waveform is more efficacious than conventional waveforms.
Subject(s)
Diagnosis, Computer-Assisted/methods , Electric Countershock/methods , Electrocardiography/methods , Therapy, Computer-Assisted/methods , Ventricular Fibrillation/diagnosis , Ventricular Fibrillation/prevention & control , Animals , Electric Countershock/adverse effects , Reproducibility of Results , Sensitivity and Specificity , Swine , Treatment OutcomeABSTRACT
BACKGROUND: In the ASsessment of the Safety of a New Thrombolytic 3 (ASSENT-3) study, full-dose tenecteplase plus enoxaparin or half-dose tenecteplase plus abciximab reduced the frequency of ischemic complications of acute myocardial infarction, when compared to full-dose tenecteplase plus unfractionated heparin. The aim of the present study was to determine the effect of these fibrinolytic regimens on 1-year mortality. METHODS AND RESULTS: Vital status at 1 year was available for 5942 patients (97.5%) of the 6095 initially enrolled in the study. At 1 year, 515 patients (8.7%) had died. Elderly or female patients and patients with low body weight, previous myocardial infarction, anterior wall myocardial infarction, and diabetes were at increased risk for death at 1 year. Mortality at 1 year was 7.9 % (n = 161) in the heparin group, 8.1% (n = 166) in the enoxaparin group, and 9.3% (n = 188) in the abciximab group (P =.226). Overall, pairwise comparisons did not show a significant difference among treatment regimens: relative risk 1.03 (95% CI 0.82-1.30) for enoxaparin versus heparin (P =.794) and relative risk 1.18 (95% CI 0.95-1.47) for abciximab versus heparin (P =.144). However, 1-year outcome tended to be worse with abciximab in diabetic patients. CONCLUSION: Mortality at 1 year after acute myocardial infarction remains high. Despite a reduction in ischemic complications after acute myocardial infarction with the use of full-dose tenecteplase plus enoxaparin or half-dose tenecteplase plus abciximab, mortality at 1 year was similar in these treatment groups.
Subject(s)
Antibodies, Monoclonal/administration & dosage , Enoxaparin/administration & dosage , Heparin/analogs & derivatives , Immunoglobulin Fab Fragments/administration & dosage , Myocardial Infarction/drug therapy , Tissue Plasminogen Activator/administration & dosage , Abciximab , Aged , Aged, 80 and over , Aspirin/administration & dosage , Drug Administration Schedule , Drug Therapy, Combination , Female , Fibrinolytic Agents/therapeutic use , Follow-Up Studies , Heparin/administration & dosage , Humans , Infusions, Intravenous , Injections, Intravenous , Injections, Subcutaneous , Male , Middle Aged , Myocardial Infarction/mortality , Survival Rate , TenecteplaseABSTRACT
Clopidogrel is increasingly used as an antiplatelet agent along with aspirin in coronary stenting due to its safety profile and clinical efficacy. This report describes a case of successful direct coronary stenting in a transplanted heart with the use of clopidogrel and aspirin therapy. Vessel patency was preserved with no evidence of in stent restenosis on 4-month follow-up angiography.
