Simultaneous occurrence of two independent vagal reflexes: a possible cause of vagal XXXX .

@entity1 @entity944 @entity1163 @entity35 @entity14481 @entity1168
A vagal origin of @entity944 has been hypothesised in @entity1 , but it has not yet been clearly demonstrated. Two vagal reflexes have been widely investigated: the diving reflex and the fear-induced central reaction, which are responsible for diving @entity1168 and alarm @entity1168 , respectively. The latter occurs in @entity1 mainly in the context of emotional @entity1163 / @entity1163 . A simultaneous occurrence of these two vagal reflexes has been observed in animals that are threatened while diving, and heart rates (HR) as low as two to six beats/min have been reported. In experiments carried out in @entity35 , a high percentage of animals that were stressed before immersion in water died suddenly due to progressive slowing of HR; autopsy revealed no signs of @entity14481 . No animals died if they had not been previously stressed. These data show that vagal @entity944 can occur when the vagal cardiac fibres are synergically stimulated by two independent reflexes. In @entity1 , it has been reported that in 10-15% of @entity1 who die after falling into water, autopsy reveals little or no water in the lungs. These sudden deaths could be due to vagal overactivity. The development of an adequate laboratory model may improve knowledge of the pathophysiology of this type of vagal @entity944 and of its prevention.
