The part of the autonomic nervous system originating in the brain stem and the lower part of the spinal cord that, in general, inhibits or opposes the physiological effects of the sympathetic nervous system, as in tending to stimulate digestive secretions, slow the heart, constrict the pupils, and dilate blood vessels.
Paroxysmal supraventricular tachycardia (PSVT) Alternative names PSVT; Supraventricular tachycardia Definition: Paroxysmal supraventricular tachycardia (PSVT) is a rapid heart rate, which occurs from time to time (paroxysmal). PSVT starts with events taking place above the ventricles.
Supraventricular tachycardia (SVT) means that from time to time your heart beats very fast for a reason other than exercise, high fever, or stress. For most people who have SVT, the heart still works normally to pump blood through the body. Types of SVT include: 1  Atrioventricular nodal reentrant tachycardia (AVNRT). 2  Atrioventricular reciprocating tachycardia (AVRT), including Wolff-Parkinson-White syndrome.