What is the X in X-mas?
preexcitation pre·ex·ci·ta·tion (prē'ěk-sī-tā'shən)
Premature activation of part of the ventricular myocardium by an impulse that travels by an anomalous path and so avoids physiological delay in the atrioventricular junction.
excitation ex·ci·ta·tion (ěk'sī-tā'shən)
The act of increasing the rapidity or intensity of the physical or mental processes; stimulation.
The complete, all-or-none response of a nerve or muscle to an adequate stimulus, ordinarily including propagation of excitation along the membranes of the cell or cells involved.
The activity produced in an organ, tissue, or cell of the body that is caused by stimulation, especially by a nerve or neuron. Compare inhibition.