An induction motor can run only at its rated speed when it is connected directly to the main supply. However, many applications need variable speed operations. This is felt the most in applications where input power is directly proportional to the cube of motor speed. In applications like the induction motor-based centrifugal pump, a speed reduction of 20% results in an energy savings of approx...

BACKGROUND Slowed or delayed myocardial activation and dispersed refractoriness predispose to reentrant excitation that may lead to ventricular fibrillation (VF). Increased ventricular electrogram duration (DeltaED) in response to extrastimuli and increased S1S2 coupling intervals at which electrogram duration starts to increase (S1S2delay) are seen both in hypertrophic cardiomyopathy (HCM) in ...

The effect of vagus nerve stimulation (VNS) upon ventricular vulnerability was studied in 30 mongrel dogs subjected to varying levels of adrenergic stimulation. Vulnerability was assessed both by determining the minimum current required to produce ventricular fibrillation (VF threshold) and by plotting VF threshold throughout the vulnerable period (VF zone). Chloralose-anesthetized animals were...

background there is the controversy concerning the main component of tobacco, which is responsible for its arrhythmogenesis. in addition, there is the lack of adequate information about the influence of combination of black tea and nicotine on heart rhythm. objectives this study aimed to examine whether pretreatment with black tea and nicotine could modulate the susceptibility to lethal ventric...

Although sodium channels have been reported to be inactive after 5-10 minutes of ventricular fibrillation (VF), their state during early VF is unknown. In 12 open-chest dogs, a floating glass microelectrode was used to record intracellular action potentials from the right ventricle during pacing and during electrically induced VF. Before any drug was administered, an initial episode of VF was c...

Ventricular fibrillation (VF) is known to produce alterations in myocardial energetics, but the mechanism of these changes remains unclear. To investigate energy metabolism during VF, phosphorus nuclear magnetic resonance spectroscopy and magnetization transfer were applied to isolated perfused ferret hearts. VF was induced either by perfusion with digitalis (strophanthidin, 30 gM) or by high-f...

BACKGROUND intracellular Na+ accumulation during ischemia and reperfusion leads to cytosolic Ca2+ overload through reverse-mode operation of the sarcolemmal Na+ -Ca2+ exchanger. Cytosolic Ca2+ accumulation promotes mitochondrial Ca2+ (Ca2+ m) overload, leading to mitochondrial injury. We investigated whether limiting sarcolemmal Na+ entry during resuscitation from ventricular fibrillation (VF) ...

BACKGROUND Several common genetic variants have been associated with either ventricular fibrillation (VF) or sudden cardiac death (SCD). However, replication efforts have been limited. Therefore, we aimed to analyze whether such variants may contribute to VF caused by first ST-elevation myocardial infarction (STEMI). METHODS We analyzed 27 single nucleotide polymorphisms (SNP) previously asso...

BACKGROUND In cardiac arrest, the ventricular fibrillation (VF) waveform, particularly amplitude spectral area (AMSA) and slope, predicts the return of spontaneous circulation (ROSC), but it is unknown whether the predictive utility differs in an acute myocardial infarction (MI), prior MI, or normal myocardium and if the waveform can distinguish the underlying myocardial state. We hypothesized ...