Effect of Ventricular Shock Strength on Cardiac Hemodynamics

Tokano, Takashi; Bach, David S.; Chang, Jason S.; Davis, James; Souza, Joseph J.; Zivin, Adam; Knight, Bradley P.; Goyal, Rajiva; Man, K. Ching; Morady, Fred; Strickberger, S. Adam

doi:10.1111/j.1540-8167.1998.tb00118.x

Cited by 135 publications

(83 citation statements)

References 14 publications

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“…9) The cause of increased risk may be postulated that the negative inotropic consequences of the shock itself could increase the risk of death, especially when the patient receives multiple shocks due to oversensing or in response to ongoing supraventricular tachycardia. [10][11][12][13] Thus, effective strategies to reduce ICD shocks are desirable. Antiarrhythmic medication is frequently administered in patients with an ICD.…”

Section: Discussionmentioning

confidence: 99%

Efficacy of Additional Amiodarone Therapy in Patients with an Implantable Cardioverter‐Defibrillator

Matsumoto

Kumagai

Ogawa

et al. 2010

Journal of Arrhythmia

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Introduction: We examined whether the additional use of amiodarone (AMD) under implantable cardioverter-defibrillator (ICD) therapy may have beneficial effects in patients at risk for lethal ventricular arrhythmias with structural heart diseases.Methods: Sixty patients (47 males, mean age, 62 AE 13 years) with structural heart disease who underwent ICD implantation were retrospectively analyzed. There were 2 groups: one group (AMD group) was treated with AMD (n ¼ 33) and the other group (non-AMD group) was treated without AMD (n ¼ 27). We compared the incidence and appropriateness of ICD shock therapy between two groups.Results: During a mean follow-up of 28 AE 17 months, we identified a total of 62 episodes in 18 patients (30%) who received ICD shock therapy. ICD shock episodes were significantly less frequent in AMD group than in non-AMD group (15% versus 48%, P < 0:01), while inappropriate shock episodes were greater in non-AMD group than in AMD group (49% versus 4%, P ¼ 0:03). In cumulative probability of shock events, the risk of events was significantly lower in AMD group (P ¼ 0:007). Of 4 patients who died in AMD group, we observed one fatal pulmonary fibrosis.Conclusions: Additional AMD therapy in patients with an ICD may be effective in reducing the risk of shock discharge. (J Arrhythmia 2010; 26: 103-110)

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Section: Discussionmentioning

confidence: 99%

Efficacy of Additional Amiodarone Therapy in Patients with an Implantable Cardioverter‐Defibrillator

Matsumoto

Kumagai

Ogawa

et al. 2010

Journal of Arrhythmia

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“…Second, with a safety margin of at least 4 to 6 J above DFTϩϩ, defibrillation efficacy seems stable over at least the first year after implantation. Finally, reducing initial shock strength may prolong battery life, decrease the incidence of postshock arrhythmias, 12,13 and reduce the incidence of hemodynamically mediated symptoms of arrhythmias, such as syncope or postepisode recovery, 23 by decreasing charge time and thus the time to therapy.…”

Section: Discussionmentioning

confidence: 99%

Efficacy and Temporal Stability of Reduced Safety Margins for Ventricular Defibrillation

et al. 2002

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Background-Traditionally, a safety margin of at least 10 J between the maximum output of the pulse generator and the energy needed for ventricular defibrillation has been used because lower safety margins were associated with unacceptably high rates of failed defibrillation and sudden cardiac death. The Low Energy Safety Study (LESS) was a prospective, randomized assessment of the safety margin requirements for modern implantable cardioverter-defibrillator (ICD) systems. Methods and Results-A total of 636 patients undergoing initial ICD implantation with a dual-coil lead and active pulse generator were evaluated. The defibrillation threshold (DFT) and enhanced DFT (DFTϩ and DFTϩϩ) were measured using a modified step-down protocol. Conversion testing of induced ventricular fibrillation before discharge, at 3 months, and at 12 months was performed in all 392 patients, as was randomization to chronic programming at either 2 steps above DFTϩϩ or maximal output in all patients. The induced ventricular fibrillation data had conversion success rates of 91.4%, 97.9%, 99.1%, 99.6%, and 99.8% for safety margins of 0, 1, 2, 3, and 4 steps above the DFTϩϩ, respectively. A margin of 4 to 6 J was adequate to maintain high conversion success over time (98.9% before discharge versus 99.2% at 12 months; PϭNS). Over a mean follow-up of 24Ϯ13 months, conversion of spontaneously occurring ventricular tachyarrhythmias Ͼ200 bpm was identical (97.3%), despite a safety margin difference of 5.2Ϯ1.1 J for the 2-step group versus 20.8Ϯ4.2 J for maximal output. Conclusions-With a rigorous implantation algorithm, a safety margin of about 5 J is adequate for safe implantation of modern ICD systems.

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“…The latest conclusion was drawn from the observation that a similar degree of ventricular stunning was noted after shocks delivered during the baseline rhythm as with shocks that terminated ventricular fibrillation. 34 …”

Section: Prognostic Importance Of Inappropriate Icd Shocksmentioning

confidence: 99%