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Chronic threshold testing of implantable cardioverter defibrillators does not increase coagulation activity or
Joseph J Smolich1, Lynette A Yates, Erica Malan
1Center for Heart and Chest Research, Department of Medicine, Monash University, Monash Medical Center, Clayton, Victoria, Australia. joe.smolich@med.monash.edu.au
Insights
Defibrillator testing does not activate blood coagulation. Studies show that brief circulatory stasis during defibrillator testing in patients with implantable cardioverter-defibrillators (ICDs) does not trigger blood clotting or platelet activation.
Area of Science:
- Cardiology
- Hematology
- Biomedical Engineering
Background:
- Implantable cardioverter-defibrillators (ICDs) are crucial for managing ventricular arrhythmias.
- The effects of defibrillator testing, specifically brief circulatory stasis, on blood coagulation are not well understood.
Purpose of the Study:
- To investigate whether defibrillator testing, including ventricular fibrillation (VF) induction, activates blood coagulation and platelet activation in patients with ICDs.
Main Methods:
- Peripheral venous blood samples were collected from 12 patients undergoing ICD DFT testing.
- Coagulation markers (prothrombin fragment 1 + 2, soluble fibrin, D-dimer) and platelet activation (P-selectin) were measured.
- Measurements were taken at baseline, post-test, and the following morning, with some patients on warfarin.
Main Results:
- No significant changes in coagulation markers or P-selectin expression were observed during or after DFT testing.
- Results remained consistent regardless of warfarin use.
- Blood coagulation and platelet activation were not significantly affected by the procedure.
Conclusions:
- Chronic threshold testing of ICDs does not appear to activate blood coagulation processes.
- These findings suggest that ICD testing is safe concerning thrombotic events.
- Further research could explore long-term implications or specific patient subgroups.
Abstract:
It is unknown if the brief periods of circulatory statis occurring with induction of VF during DFT testing in patients with an ICD activate blood coagulation processes. To address this question, coagulation activity and platelet activation were measured in peripheral venous blood samples obtained from 12 patients undergoing DFT testing under general anesthesia, 3 (n = 11) or 6 months (n = 1) after ICD implantation for recurrent ventricular arrhythmias. Five patients were anticoagulated with warfarin and two to six episodes of VF (median five) were induced per patient. Blood samples were drawn at baseline, after each DFT test and on the following morning. Coagulation activity was assessed by measuring prothrombin fragment 1 + 2 (F1 + 2) (a marker of thrombin generation), soluble fibrin (a marker of fibrin production), and D-dimer (a breakdown product of cross-linked fibrin). Platelet activation was evaluated by measuring the expression P-selectin on the platelet surface using flow cytometry. No significant changes in F1 + 2, soluble fibrin, D-dimer, or P-selectin expression occurred during DFT testing, or between baseline and morning after samples. Moreover, results were unaffected by warfarin. These findings suggest that chronic threshold testing of implantable cardioverter defibrillators is not associated with activation of blood coagulation processes.