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Michael Baubin - One of the best experts on this subject based on the ideXlab platform.
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Waveform analysis of biphasic external Defibrillators
Resuscitation, 2001Co-Authors: Ulrich Achleitner, Klaus Rheinberger, Bernhard Furtner, Anton Amann, Michael BaubinAbstract:Background and Objectie: All internal Defibrillators and some external Defibrillators use biphasic waveforms. The study analysed the discharged waveform pulses of two manual and two semi-automated biphasic external Defibrillators. Methods and Results: The Defibrillators were discharged into resistive loads of 25, 50 and 100 simulating the patient’s transthoracic impedance. The tested biphasic Defibrillators differed in initial current as well as initial voltage, varying from 10.9 to 73.3 A and from 482.8 to 2140.0 V, respectively. The energies of the manual Defibrillators set at 100, 150 and 200 J deviated by up to +19.1 or −28.9% from the selected energy. Impedance-normalised delivered energy varied from 1.0 to 12.5 J/. Delivered energy, shock duration and charge flow were examined with respect to the total pulse, its splitting into positive and negative phases and their impedance dependence. For three Defibrillators pulse duration increased with the resistive load, whereas one Defibrillator always required 9.9 ms. All tested Defibrillators showed a higher charge flow in the positive phase. Defibrillator capacitance varied between approximately 200 and 100 F and internal resistance varied from 2.0 to 7.6 . Defibrillator waveform tilt ranged from −13.1 to 61.4%. Conclusions: The tested Defibrillators showed remarkable differences in their waveform design and their varying dependence on transthoracic impedance. © 2001 Elsevier Science Ireland Ltd. All rights reserved.
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Waveforms of external Defibrillators: analysis and energy contribution.
Resuscitation, 1999Co-Authors: Ulrich Achleitner, Anton Amann, Martin Stoffaneller, Michael BaubinAbstract:Abstract Background and objective: Defibrillation is the most important therapy for terminating ventricular fibrillation in cardiac arrest patients. In addition to performing defibrillation at the earliest possible time, appropriate pulse energy and optimal waveform seem to be crucial for success. Emergency medical service personnel use different Defibrillators and rely on their similarity of energy content. This study examined the true pulse energy content and waveform of 17 commonly used Defibrillators. Methods and results: Defibrillation energies were selected to be 30, 200 or 360 J and Defibrillators were discharged into test resistors, simulating transthoracic impedances of 25, 50 or 100Ω. Pulse energy deviated by up to +23% or −29% from the selected energy. Pulse energy within the initial 8 ms ranged from 90 to 30% of total pulse energy. Fourteen Defibrillators utilising damped sinusoidal waveforms produced a monophasic pulse when discharged into resistances of 50Ω and 100Ω. Conclusions: Defibrillators used at the same energy settings do not necessarily produce the same defibrillation pulse energy. All but one Defibrillator actually use monophasic waveforms, leaving the potential advantage of biphasic waveforms unused. Energy accuracy of Defibrillators needs to be improved, and biphasic waveforms should be used more.
Didier Klug - One of the best experts on this subject based on the ideXlab platform.
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adding defibrillation therapy to cardiac resynchronization on the basis of the myocardial substrate
Journal of the American College of Cardiology, 2017Co-Authors: Sergio Barra, Serge Boveda, Rui Providencia, Nicolas Sadoul, Rudolf Duehmke, Christian Reitan, Rasmus Borgquist, Kumar Narayanan, Francoise Hiddenlucet, Didier KlugAbstract:Abstract Background Patients with nonischemic dilated cardiomyopathy (DCM) may be at lower risk for ventricular arrhythmias compared with those with ischemic cardiomyopathy (ICM). In addition, DCM has been identified as a predictor of positive response to cardiac resynchronization therapy (CRT). Objectives The aim of this study was to investigate the impact of an additional implantable cardioverter-Defibrillator over CRT, according to underlying heart disease, in a large study group of primary prevention patients with heart failure. Methods This was an observational, multicenter, European cohort study of 5,307 consecutive patients with DCM or ICM, no history of sustained ventricular arrhythmias, who underwent CRT implantation with (n = 4,037) or without (n = 1,270) a Defibrillator. Propensity-score and cause-of-death analyses were used to compare outcomes. Results After a mean follow-up period of 41.4 ± 29.0 months, patients with ICM had better survival when receiving CRT with a Defibrillator compared with those who received CRT without a Defibrillator (hazard ratio for mortality adjusted on propensity score and all mortality predictors: 0.76; 95% confidence interval [CI]: 0.62 to 0.92; p = 0.005), whereas in patients with DCM, no such difference was observed (hazard ratio: 0.92; 95% CI: 0.73 to 1.16; p = 0.49). Compared with recipients of Defibrillators, the excess mortality in patients who did not receive Defibrillators was related to sudden cardiac death in 8.0% among those with ICM but in only 0.4% of those with DCM. Conclusions Among patients with heart failure with indications for CRT, those with DCM may not benefit from additional primary prevention implantable cardioverter-Defibrillator therapy, as opposed to those with ICM.
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Adding Defibrillation Therapy to Cardiac Resynchronization on the Basis of the Myocardial Substrate
Journal of the American College of Cardiology, 2017Co-Authors: Sergio Barra, Serge Boveda, Rui Providencia, Nicolas Sadoul, Rudolf Duehmke, Christian Reitan, Rasmus Borgquist, Kumar Narayanan, Françoise Hidden-lucet, Didier KlugAbstract:Background: Patients with nonischemic dilated cardiomyopathy (DCM) may be at lower risk for ventricular arrhythmias compared with those with ischemic cardiomyopathy (ICM). In addition, DCM has been identified as a predictor of positive response to cardiac resynchronization therapy (CRT).Objectives: The aim of this study was to investigate the impact of an additional implantable cardioverter-Defibrillator over CRT, according to underlying heart disease, in a large study group of primary prevention patients with heart failure.Methods: This was an observational, multicenter, European cohort study of 5,307 consecutive patients with DCM or ICM, no history of sustained ventricular arrhythmias, who underwent CRT implantation with (n = 4,037) or without (n = 1,270) a Defibrillator. Propensity-score and cause-of-death analyses were used to compare outcomes.Results: After a mean follow-up period of 41.4 ± 29.0 months, patients with ICM had better survival when receiving CRT with a Defibrillator compared with those who received CRT without a Defibrillator (hazard ratio for mortality adjusted on propensity score and all mortality predictors: 0.76; 95% confidence interval [CI]: 0.62 to 0.92; p = 0.005), whereas in patients with DCM, no such difference was observed (hazard ratio: 0.92; 95% CI: 0.73 to 1.16; p = 0.49). Compared with recipients of Defibrillators, the excess mortality in patients who did not receive Defibrillators was related to sudden cardiac death in 8.0% among those with ICM but in only 0.4% of those with DCM.Conclusions: Among patients with heart failure with indications for CRT, those with DCM may not benefit from additional primary prevention implantable cardioverter-Defibrillator therapy, as opposed to those with ICM.
Ulrich Achleitner - One of the best experts on this subject based on the ideXlab platform.
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Waveform analysis of biphasic external Defibrillators
Resuscitation, 2001Co-Authors: Ulrich Achleitner, Klaus Rheinberger, Bernhard Furtner, Anton Amann, Michael BaubinAbstract:Background and Objectie: All internal Defibrillators and some external Defibrillators use biphasic waveforms. The study analysed the discharged waveform pulses of two manual and two semi-automated biphasic external Defibrillators. Methods and Results: The Defibrillators were discharged into resistive loads of 25, 50 and 100 simulating the patient’s transthoracic impedance. The tested biphasic Defibrillators differed in initial current as well as initial voltage, varying from 10.9 to 73.3 A and from 482.8 to 2140.0 V, respectively. The energies of the manual Defibrillators set at 100, 150 and 200 J deviated by up to +19.1 or −28.9% from the selected energy. Impedance-normalised delivered energy varied from 1.0 to 12.5 J/. Delivered energy, shock duration and charge flow were examined with respect to the total pulse, its splitting into positive and negative phases and their impedance dependence. For three Defibrillators pulse duration increased with the resistive load, whereas one Defibrillator always required 9.9 ms. All tested Defibrillators showed a higher charge flow in the positive phase. Defibrillator capacitance varied between approximately 200 and 100 F and internal resistance varied from 2.0 to 7.6 . Defibrillator waveform tilt ranged from −13.1 to 61.4%. Conclusions: The tested Defibrillators showed remarkable differences in their waveform design and their varying dependence on transthoracic impedance. © 2001 Elsevier Science Ireland Ltd. All rights reserved.
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Waveforms of external Defibrillators: analysis and energy contribution.
Resuscitation, 1999Co-Authors: Ulrich Achleitner, Anton Amann, Martin Stoffaneller, Michael BaubinAbstract:Abstract Background and objective: Defibrillation is the most important therapy for terminating ventricular fibrillation in cardiac arrest patients. In addition to performing defibrillation at the earliest possible time, appropriate pulse energy and optimal waveform seem to be crucial for success. Emergency medical service personnel use different Defibrillators and rely on their similarity of energy content. This study examined the true pulse energy content and waveform of 17 commonly used Defibrillators. Methods and results: Defibrillation energies were selected to be 30, 200 or 360 J and Defibrillators were discharged into test resistors, simulating transthoracic impedances of 25, 50 or 100Ω. Pulse energy deviated by up to +23% or −29% from the selected energy. Pulse energy within the initial 8 ms ranged from 90 to 30% of total pulse energy. Fourteen Defibrillators utilising damped sinusoidal waveforms produced a monophasic pulse when discharged into resistances of 50Ω and 100Ω. Conclusions: Defibrillators used at the same energy settings do not necessarily produce the same defibrillation pulse energy. All but one Defibrillator actually use monophasic waveforms, leaving the potential advantage of biphasic waveforms unused. Energy accuracy of Defibrillators needs to be improved, and biphasic waveforms should be used more.
David E Haines - One of the best experts on this subject based on the ideXlab platform.
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cardiac arrest survival after implementation of automated external Defibrillator technology in the in hospital setting
Critical Care Medicine, 2009Co-Authors: Matthew S Forcina, Ali Y Farhat, William W Oneill, David E HainesAbstract:Background: Survival from ventricular tachycardia (VT) or ventricular fibrillation (VF) arrest is inversely related to delay to defibrillation. The automated external Defibrillator (AED) has improved survival after out-of-hospital VT/VF arrest by decreasing time to defibrillation. The purpose of this study was to determine whether survival to discharge after in-hospital cardiac arrest caused by VT/VF could be improved via an institution-wide change from a standard monophasic Defibrillator to a biphasic Defibrillator with AED capability. Methods and Results: After extensive staff education, all standard Defibrillators were replaced by AEDs at a single institution. Outcomes were analyzed for 1 year before the change and 1 year after the change using a prospective database. In patients whose initial rhythm was VT/VF, AEDs were not associated with improvement in time to first shock (median 1 minute for both cohorts, p = 0.79) or survival to discharge (31% vs. 29%, p = 0.8) compared with standard Defibrillators. In patients whose initial rhythm was asystole or pulseless electrical activity, AEDs were associated with a significant decrease in survival (15%) compared with standard Defibrillators (23%, p = 0.04). The overall AED cohort showed no difference in survival to discharge compared with the standard cohort (18% vs. 23%, p = 0.09). Conclusions: Replacement of standard monophasic Defibrillators with biphasic AEDs was associated with unchanged survival after in-hospital VT/VF arrest and decreased survival after in-hospital asystole or pulseless electrical activity arrest.
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cardiac arrest survival after implementation of automated external Defibrillator technology in the in hospital setting
Critical Care Medicine, 2009Co-Authors: Matthew S Forcina, Ali Y Farhat, William W Oneill, David E HainesAbstract:Background: Survival from ventricular tachycardia (VT) or ventricular fibrillation (VF) arrest is inversely related to delay to defibrillation. The automated external Defibrillator (AED) has improved survival after out-of-hospital VT/VF arrest by decreasing time to defibrillation. The purpose of this study was to determine whether survival to discharge after in-hospital cardiac arrest caused by VT/VF could be improved via an institution-wide change from a standard monophasic Defibrillator to a biphasic Defibrillator with AED capability. Methods and Results: After extensive staff education, all standard Defibrillators were replaced by AEDs at a single institution. Outcomes were analyzed for 1 year before the change and 1 year after the change using a prospective database. In patients whose initial rhythm was VT/VF, AEDs were not associated with improvement in time to first shock (median 1 minute for both cohorts, p = 0.79) or survival to discharge (31% vs. 29%, p = 0.8) compared with standard Defibrillators. In patients whose initial rhythm was asystole or pulseless electrical activity, AEDs were associated with a significant decrease in survival (15%) compared with standard Defibrillators (23%, p = 0.04). The overall AED cohort showed no difference in survival to discharge compared with the standard cohort (18% vs. 23%, p = 0.09). Conclusions: Replacement of standard monophasic Defibrillators with biphasic AEDs was associated with unchanged survival after in-hospital VT/VF arrest and decreased survival after in-hospital asystole or pulseless electrical activity arrest.
Paul Schurmann - One of the best experts on this subject based on the ideXlab platform.
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Device Therapy for Sudden Cardiac Death Prophylaxis After Acute Coronary Syndrome: When and Why?
Current Cardiology Reports, 2020Co-Authors: Miguel Valderrabano, Paul SchurmannAbstract:Implantable cardioverter-Defibrillators (ICDs) are a powerful tool in preventing sudden cardiac death due to ventricular arrhythmias in ischemic cardiomyopathy. ICD indications and timing in acute coronary syndromes are unclear. Purpose of Review We reviewed several trials that delineated the indications for a cardiac Defibrillator in patients with coronary artery disease. Recent Findings The role of cardiac Defibrillators in secondary prevention has been well established by AVID, CIDS, and CASH trials. AVID showed reduction in both all-cause mortality and arrhythmic death while the two smaller trials showed only improvement in arrhythmic death. Similarly, trials like MADIT, CABG Patch, MUSTT, MADIT-II, DINAMIT, and the IRIS trial have fine-tuned the indications for ICD in primary prevention of sudden cardiac death. Benefits of an ICD were most pronounced in those with reduced ejection fraction and 40 days or more since myocardial infarction or in those who were not immediately post revascularization. The recent VEST trial aimed to study wearable cardioverter-Defibrillators (WCDs) in patients who did not have an indication for an implantable Defibrillator. The arrhythmic deaths (1.6% vs. 2.4%) were not reduced by the WCD. Summary Based on consistent reduction in arrhythmic death in all primary and secondary prevention trials, Defibrillators are effective in carefully selected patients.
