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Episodes of vasovagal syncope are typically recurrent and usually occur when the predisposed person is exposed to a specific trigger. Before losing consciousness, the individual frequently experiences early signs or symptoms such as lightheadedness, nausea, the feeling of being extremely hot or cold (accompanied by sweating), ringing in the ears, an uncomfortable feeling in the heart, fuzzy ...
Vagovagal reflex refers to gastrointestinal tract reflex circuits where afferent and efferent fibers of the vagus nerve [1] coordinate responses to gut stimuli via the dorsal vagal complex in the brain. The vagovagal reflex controls contraction of the gastrointestinal muscle layers in response to distension of the tract by food.
The “Cardioneuroablation” is a technique created in the nineties and patented in USA, aiming to eliminate the cardiac branch of vagal reflex in order to treat the neurocardiogenic syncope without pacemaker implantation. [6] [7] It is performed without surgery, by using radiofrequency catheter ablation with one-day hospital. [citation needed]
In most cases, vagal tone is not measured directly. Instead the processes affected by the vagus nerve – specifically heart rate and heart rate variability – are measured and used as a surrogate for vagal tone. Increased vagal tone (and thus vagal action) is generally associated with a lower heart rate and increased heart rate variability.
A feedback response to the medulla is triggered via the afferent vagus nerve. The high (ineffective) sympathetic activity is thereby modulated by vagal (parasympathetic) outflow leading to excessive slowing of heart rate. The abnormality lies in this excessive vagal response causing loss of blood flow to the brain. [9]
Cold shock response is a series of neurogenic cardio-respiratory responses caused by sudden immersion in cold water. In cold water immersions, such as by falling through thin ice, cold shock response is perhaps the most common cause of death. [ 1 ]
This does not happen in adults because sympathetic stimulation overpowers the vagal response. However, for those adults who have received drugs such as beta blocker, calcium channel blocker, and digoxin have an increased risk of developing bradycardia. Atropine is a muscarinic receptor antagonist, thus blocking the vagal response. The dose is ...
As exposure continues, it is expected that the phobic response will become less pronounced, and symptoms less debilitating. [12] While AT targets the phobia's physiological response, aiming to raise blood pressure and directly prevent fainting, AR focuses mainly on helping an individual avoid the phobia's associated anxiety.