The purpose of this study was to evaluate the efficacy of a unique program of ventilation-feedback training combined with leg-cycle exercise to improve exertional endurance and decrease perceived dyspnea in patients with chronic obstructive pulmonary disease (COPD). Thirty-nine patients (67.5 +/- 8.1 yr of age) with moderate to severe COPD (42.6% of predicted forced expiratory volume in 1 s) we...

BACKGROUND Continued breathing following ventricular fibrillation has here-to-fore not been described. METHODS We analyzed the spontaneous ventilatory activity during the first several minutes of ventricular fibrillation (VF) in our isoflurane anesthesized swine model of out-of-hospital cardiac arrest. The frequency and type of ventilatory activity was monitored by pneumotachometer and main s...

BACKGROUND Thyrotoxicosis is known to be associated with sinus tachycardia and supraventricular tachyarrhythmias, but rarely with ventricular fibrillation (Vf), which has only occurred in some patients with hypokalemic periodic paralysis or ischemic heart disease. PATIENT FINDINGS We present three men who were transferred to our hospital with Graves' disease who developed idiopathic Vf. None ...

BACKGROUND Ventricular fibrillation (VF) during heart failure is characterized by stable reentrant spiral waves (rotors). Apamin-sensitive small-conductance calcium-activated potassium currents (IKAS) are heterogeneously upregulated in failing hearts. We hypothesized that IKAS influences the location and stability of rotors during VF. METHODS AND RESULTS Optical mapping was performed on 9 rab...

The restitution kinetics of action potential duration (APD) were investigated in paced canine Purkinje fibers (P; n = 9) and endocardial muscle (M; n = 9), in isolated, perfused canine left ventricles during ventricular fibrillation (VF; n = 4), and in endocardial muscle paced at VF cycle lengths (simulated VF; n = 4). Restitution was assessed with the use of two protocols: delivery of a single...

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...

Ventricular tachycardia (VT) is considered to be the most common precursor of ventricular fibrillation (VF). However, the mechanisms underlying the transition from VT to VF remain unclear. Here, we investigated whether and how perfusion of the heart with verapamil, a blocker of L-type calcium channels, changed the macro-dynamics of the heart between VT and VF. The experiments were performed wit...

INTRODUCTION Implantation of a implantable cardioverter defibrillator (ICD) is viewed universally as the "gold standard" therapy for patients with idiopathic ventricular fibrillation (VF). We sought to study the long-term value of electrophysiologic (EP)-guided therapy with Class IA antiarrhythmic drugs in patients with idiopathic VF with or without the Brugada syndrome. METHODS AND RESULTS W...

INTRODUCTION The roles of pacing interval (PI) and pacing strength (PS) in ventricular fibrillation (VF) induced by rapid pacing with 1 : 1 capture remain unclear. MATERIAL AND METHODS Epicardial unipolar electrograms (UEs) were simultaneously recorded using contact mapping in 11 swine. Activation-recovery interval (ARI) restitution was constructed at 4 sites, i.e. the apex and base of the le...

Plants of the genus Valeriana (Valerianaceae) are used in traditional medicine as a mild sedative, antispasmodic and tranquilizer in many countries. This study was undertaken to explore the neurobehavioral effects of systemic administration of a valepotriate extract fraction of known quantitative composition of Valeriana glechomifolia (endemic of southern Brazil) in mice. Adult animals were tre...