promotion When compared with lidocaine both amiodarone and n
When compared with lidocaine, both amiodarone and nifekalant were proved similarly effective for ventricular arrhythmias suppression. These drugs, however, have characteristic adverse effects, such as negative inotropic and chronotropic outcomes (amiodarone), and QT prolongation resulting in torsade de pointes (nifekalant). One should be aware of frequent QT-interval prolongation after nifekalant administration. Nevertheless, the QT interval measurement is often difficult because of abnormal ST- or T-wave morphology due to ischemia or electrolyte disturbances after cardiopulmonary resuscitation. However, this agent has several advantages over amiodarone, such as an early onset and offset of an antiarrhythmic effect, and a minimal effect on hemodynamics and cardiac contractility. Sotalol has a similar effect but causes beta-adrenergic blockade, which is contraindicated in bradycardic patients. Although several studies on nifekalant have been reported thus far, in most of them, including our study, a comparison among antiarrhythmic drugs was difficult because of an insufficient numbers of patients and heterogeneous study designs .
Most of the previous studies consistently showed that antiarrhythmic administration had little or no benefit on the in-hospital mortality, and AHA guideline stated that no drug has yet been shown to increase the survival or neurological outcome after a cardiac arrest that is due to ventricular arrhythmias . As with the previous studies, no significant differences in mortality were observed among the three antiarrhythmic drugs used in our study. These findings suggest that the choice of antiarrhythmic agents has little impact on the survival of the ventricular arrhythmias patients. However, we consider that these drugs exhibit short-term effects when used for the stabilization of patients` status in clinical practice. It is hoped that long-term benefit will be evaluated in a well-designed clinical trial.
This study has several limitations. First, it promotion was a non-randomized study with a small sample size; thus, there is the possibility of several biases in patient selection. In the lidocaine group, the prevalence of cardiopulmonary arrest was relatively high. However, we adjusted for this effect on outcome in our univariate logistic regression model, and the results were similar to those adjusted by propensity scores. Another issue was an over-fitting in estimating the propensity score in our logistic regression model. This was due to a small number of events. In this direction, some previous reports addressed this issue by using propensity scores as a method of data reduction. Therefore, we handled this problem in the same fashion [23,24]. In addition, there is no established method to estimate propensity scores and to compare effects between more than two treatment arms. We used multinomial logistic regression analysis to generate these scores and used them in logistic regression as covariates with treatment categories . The tests of goodness of fit in this model showed that this hypothesis was acceptable in this study; however, residual differences may be explained by confounding effects of variables, such as physician׳s preference that could not be measured.
Introduction Atrial fibrillation (AF) is a common finding in the postoperative course after cardiac surgery. It occurs in 20–40% of the patients after coronary artery bypass graft (CABG) and in about 50% of those who undergo cardiac valve surgeries [1–3]. Clinical manifestations of postoperative AF (POAF) range from asymptomatic forms to heart failure and/or embolic events, which increase the cost and in-hospital stay [4,5]. POAF etiology involves electrical, metabolic, neurohumoral, and inflammatory disorders that modify the atrial geometry and electrophysiology. Effective therapies preventing POAF can cause hypotension and symptomatic bradycardia, both undesirable side effects after cardiac surgery and unfortunately, its incidence has not been reduced significantly during last decade. Pleiotropic effects of atorvastatin have been considered protective against POAF [6–8]. Atorvastatin reduces postoperative Systemic Inflammatory Response Syndrome (SIRS); prevents atrial remodeling and modulates thrombogenesis, oxidation and atrial fibrosis. A direct electrophysiological effect inhibiting calcium increase in the atrial myocyte, thus favoring anti-sympathetic action of the autonomic nervous system, has also been proposed. Randomized studies regarding atorvastatin use  have reported a 40–60% reduction in POAF incidence avoiding undesirable side effects. Nevertheless, all these studies were biased in sample selection (predominantly included CABG procedures), drug dosing, and concomitant administration of beta-blockers (recognized as prophylactic therapy for POAF).