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Defibrillation Threshold Testing (defibrillation + threshold_testing)
Selected AbstractsDefibrillation Threshold Testing in the 21st Century: Necessary or Not?PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 5 2009STEPHEN C. VLAY M.D. No abstract is available for this article. [source] Defibrillation Threshold Testing: Tradition or Necessity?PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 5 2009CHRISTOF KOLB M.D. Implantable cardioverter defibrillators (ICDs) have become an essential tool for primary and secondary prevention of sudden cardiac death. Traditionally, defibrillation threshold (DFT) testing is part of the "lege artis" ICD implantation. Taking into consideration that the absolute mortality reduction in primary prevention trials is estimated around 8% and in secondary prevention trials around 7%, it is only in these patients that an acceptable DFT is expected to affect survival. Using a high-energy ICD, the likelihood of obtaining an inadequate DFT is about 2.5%. Thus, the number of patients needed to be subjected to DFT testing in order to avert one potential death is about 500. Application of antitachycardia pacing for rapid ventricular tachycardias further reduces the percentage of patients dependent on reliable ICD defibrillation capability. Thus, the mortality rate that can be prevented by DFT testing is below 0.2%. This contrasts a 0.4% risk of life-threatening complications and a low but not negligible mortality risk owed to the procedure. Although in light of these data the balance between DFT-related risk and benefit seems to tilt toward the former, insights gained from prospective randomized trials will clarify whether the abandonment of routine DFT testing can be claimed on a rightful basis. [source] Implantable Cardioverter Defibrillator Sensing Failure Due to Endocardial R Wave Electrical AlternansJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2002KRIT JONGNARANGSIN M.D. Electrical Alternans and ICD Undersensing. A 71-year-old patient underwent routine single-chamber implantable cardioverter defibrillator (ICD) generator replacement. During defibrillation threshold testing, ventricular tachycardia was induced but the ICD failed twice to properly detect the tachycardia due to endocardial R wave alternans and sensing of every other beat. The problem was resolved by inserting a separate sensing/pacing lead positioned further away from the existing ICD lead. [source] Delayed Cardiac Perforation by Defibrillator Lead Placed in the Right Ventricular Outflow Tract Resulting in Massive Pericardial EffusionPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 12 2008ERNEST W. LAU M.D. A 76-year-old man received a dual-chamber implantable cardioverter defibrillator (ICD), with the defibrillator lead positioned within the right ventricular outflow tract. The lead parameters at the time of implantation were satisfactory and the postprocedure chest X-ray showed the leads were in place. The patient was cardioverted from atrial fibrillation during defibrillation threshold testing and commenced on anticoagulation immediately. One month post implantation, he experienced multiple ventricular tachycardia episodes all successfully treated with antitachycardia pacing and shocks by his ICD, but he fell and hit his chest against a hard surface during one of these attacks. He developed a massive pericardial effusion and computed tomography confirmed cardiac perforation by the defibrillator lead. Pericardiocentesis was performed and the defibrillator lead replaced with a different model positioned at the right ventricular apex. The patient made an uneventful recovery. The management and avoidance of delayed cardiac perforation by transvenous leads were discussed. [source] Influence of Drive Cycle Length on Initiation of Ventricular Fibrillation During Implantable Cardioverter Defibrillator Threshold TestingPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 9 2006NEIL K. SANGHVI Background: Programmed electrical stimulation of the heart as a method to induce tachyarrhythmias has been described since the 1960s. To date, no study has examined optimal drive cycle length in the induction of ventricular fibrillation (VF) during defibrillation threshold testing after implantable cardioverter-defibrillator placement. We hypothesized that longer drive cycle length, by means of the longer action potential duration, would promote intramyocardial phase 2 reentry and facilitate induction of VF. Methods: Fifty consecutive implants were randomized in a prospective crossover format for this study. The group consisted of 40 men and 10 women, with each patient receiving either a 400 or 600 ms initial drive train prior to 1.2 J internal shock on the T wave with a goal to induce ventricular fibrillation. The timing of the T wave shock was determined by measuring the interval from the beginning of the QRS to the apex of the T wave in lead II. Successful inductions were defibrillated via the cardioverter defibrillator. Patients were then crossed over and the protocol repeated. Results: Twenty of 23 (87%) patients were successfully induced into VF in the initial 400 ms drive train arm whereas 22 of 27 (81%) were successfully induced in the 600 ms arm. Thus, a total of 44 (88%) patients were successfully induced at 400 ms, 41 (82%) patients were successfully induced at 600 ms, and 2 (4%) patients were not inducible at either cycle length, but were inducible with 50 Hz ventricular stimulation. However, no significant difference was noted between the two groups. Conclusion: No investigation to date has questioned whether a relationship exists between drive cycle length and initiation of ventricular fibrillation. Our study addresses this question, though negative for difference between 400 and 600 ms drive trains. Further research into optimal strategies for inducing ventricular fibrillation will minimize patient sedation time and discomfort while undergoing defibrillator threshold testing. [source] | ||||||||||