Electrical alternation of the T-wave: clinical and experimental evidence of its relationship with the sympathetic nervous system and with the long Q-T syndrome.

In a patient affected by the "long Q-T" syndrome we observed episodes of alternation of the T-wave associated with emotional or physical stresses. In anesthetized and vagotomized cats, we could reproduce both the lengthening of the Q-T interval and episodes of alternation of the T-wave by electrical stimulation of the left stellate ganglion. Our experiments provide further support on the relationships between the "long Q-T" syndrome and the sympathetic nervous system and indicate that alternation of the T-wave may depend on abrupt increases in the sympathetic discharge.