RATIONALE Ventricular fibrillation (VF) leads to global ischemia. The modulation of ischemia-dependent pathways may alter the electrophysiological evolution of VF. OBJECTIVE We addressed the hypotheses that there is regional disease-related expression of K(ATP) channels in human cardiomyopathic hearts and that K(ATP) channel blockade promotes spontaneous VF termination by attenuating spatiote...

Hyperkalemia increases the organization of ventricular fibrillation (VF) and may also terminate it by mechanisms that remain unclear. We previously showed that the left-to-right heterogeneity of excitation and wave fragmentation present in fibrillating guinea pig hearts is mediated by chamber-specific outward conductance differences in the inward rectifier potassium current (I(K1)). We hypothes...

Background Performance on the verb fluency (VF) task may be influenced by administration procedures and demographic factors of each population. Objective The aim of this study was to verify whether the previous administration of semantic and phonemic verbal fluency tasks can influence performance on VF; and to analyze the correlation of VF performance with education, age and type of errors in...

A 10 min ligation of the left anterior descending coronary artery in anaesthetized pigs resulted in ventricular fibrillation (VF) in 70% of control and propranolol-treated animals. Felodipine (10 nmol kg-1) not only reduced ventricular ectopic activity by 90%, but also completely abolished VF. When a second occlusion was applied after 20 min of reperfusion, felodipine was less effective against...

BACKGROUND Little is known about the effects of heart failure (HF) on the defibrillation threshold (DFT) and the characteristics of activation during ventricular fibrillation (VF). METHODS AND RESULTS HF was induced by rapid right ventricular (RV) pacing for at least 3 weeks in 6 dogs. Another 6 dogs served as controls. Catheter defibrillation electrodes were placed in the RV apex, the superi...

It is commonly believed that vagally-mediated bradyeardia predisposes to ventricular fibrillation (VF) during acute myocardial ischemia. Recent experimental studies, however, have shown that bradycardia and vagal stimulation independently raise the threshold for electrically induced VF in the ischemic canine heart. To determine the influence of vagal stimulation on the spontaneous development o...

BACKGROUND Sodium-hydrogen exchanger isoform-1 (NHE-1) activation worsens functional myocardial abnormalities associated with ischemia and reperfusion. We hypothesize that these abnormalities may limit cardiac resuscitation from ventricular fibrillation (VF) and investigated whether NHE-1 inhibition with the benzoylguanidine derivative cariporide could improve resuscitability, postresuscitation...

Myocardial ATP-gated potassium channels (K-ATPs) are critical in the intracellular signaling cascade resulting in ischemic preconditioning (IP). Mitochondrial K-ATP channels seem to be responsible for IP, whereas the functions of K-ATP channels in the sarcolemmal membrane are less well understood. The proarrhythmic potential of specific versus nonspecific opening of K-ATP channels has not been ...

It is commonly believed that vagally-mediated bradyeardia predisposes to ventricular fibrillation (VF) during acute myocardial ischemia. Recent experimental studies, however, have shown that bradycardia and vagal stimulation independently raise the threshold for electrically induced VF in the ischemic canine heart. To determine the influence of vagal stimulation on the spontaneous development o...