Optimization of initial energy for cardioversion of atrial tachyarrhythmias with biphasic shocks.

OBJECTIVE: Recommendations for optimal first-shock energies with biphasic waveforms are conflicting. We evaluated prospectively the relation between type and duration of atrial tachyarrhythmias and the probability of successful cardioversion with a specific biphasic shock waveform to develop recommendations for the initial energy setting aiming at the lowest total cumulative energy with 2 or less consecutive shocks. METHODS: We analyzed 453 consecutive patients undergoing their first transthoracic electrical cardioversion, including 358 attempts for atrial fibrillation (AF) and 95 attempts for atrial flutter (AFL) or atrial tachycardia (AT). A step-up protocol with a truncated exponential biphasic waveform starting at 50 J was used. Total cumulative energies were estimated under the assumption of a 2-tiered escalating shock protocol with different initial energy settings and a "rescue shock" of 250 J for AFL/AT or 360 J for AF. The initial energy setting leading to the lowest total cumulative energy was regarded as the optimal first-shock level. RESULTS: Cardioversion was successful in 448 patients (cumulative efficacy, 99 %). In patients with AFL/AT, the lowest total cumulative energy was attained with an initial energy setting of 50 J. In patients with AF, lowest values were achieved with an initial energy of 100 J for arrhythmia durations of 2 days or less and an initial energy of 150 J for arrhythmia durations of more than 2 days. CONCLUSION: We recommend an initial energy setting of 50 J in patients with AFL/AT, of 100 J in patients with AF 2 days or less, and of 150 J with AF more than 2 days.

Does early administration of selenium improve neurological outcome after cardiac arrest?

OBJECTIVE: Existing data indicate that selenium supplementation may be beneficial in critically ill patients and in those with ischemic stroke. The purpose of this retrospective study was to explore the influence of early administration of selenium on neurological outcome after cardiopulmonary resuscitation (CPR). METHODS: We examined 227 consecutive unconscious patients after CPR and excluded 1 individual. The decision to administer selenium was left to the discretion of the attending physician, resulting in 124 patients (55%) who received intravenous selenium (200-1000 microg/d) for a median of 5 days after CPR. Patients were classified according to the best Glasgow-Pittsburgh cerebral performance categories (CPCs 1-5) achieved within 6 months of follow-up. RESULTS: The rate of regaining consciousness (CPC 1-3) after CPR was 58%. Multivariable logistic regression analysis confirmed a shockable first monitored rhythm (adjusted odds ratio, 3.73; 95% confidence interval, 1.85-7.52; P < .001), time to return of spontaneous circulation (adjusted odds ratio, 0.94; 95% confidence interval, 0.91-0.96; P < .001), administration of selenium (adjusted odds ratio, 2.38; 95% confidence interval, 1.19-4.76; P = .014), and the Simplified Acute Physiology Score II (adjusted odds ratio, 0.96; 95% confidence interval, 0.93-0.99; P = .034) as independent predictors of regaining consciousness after CPR. Survival at 6 months of follow-up was not improved significantly by selenium. CONCLUSION: This retrospective analysis leads to the hypothesis that early administration of selenium may improve neurological outcome after cardiac arrest.

Prediction of neurological outcome after cardiopulmonary resuscitation by serial determination of serum neuron-specific enolase.

AIMS: Data on the diagnostic accuracy of neuron-specific enolase (NSE) as marker of hypoxic brain damage are conflicting. The purpose of this prospective observational cohort study was to explore the prognostic value of serum NSE after cardiopulmonary resuscitation (CPR) and to define the most sensitive cutoff value with a specificity of 100% for the prediction of persistent coma. METHODS AND RESULTS: Serum NSE concentrations were serially determined in 227 consecutive unconscious patients after CPR who were classified according to the best Glasgow-Pittsburgh cerebral performance categories (CPC, 1-4) achieved within 6 months follow-up. Sixteen patients were excluded due to incomplete NSE data and 34 due to death under analgesia sedation. The prevalence of poor neurological outcome (persistent coma, CPC 4) in our 177 analysed patients was 33%. At a specificity of 100%, a peak NSE concentration above 80 ng/mL predicted persistent coma with a sensitivity of 63%, a positive predictive value of 100%, a negative predictive value of 84%, and a predictive accuracy of 88%. CONCLUSION: A peak serum NSE concentration exceeding 80 ng/mL is a highly specific but only moderately sensitive marker for a poor neurological outcome after CPR.