The changes in electrical potential generated by the muscle cell membrane or nerve cell tissue in response to intrinsic or extrinsic stimulation. A pacing lead with an attachment mechanism, such as a screw-in tip, to actively secure it in the cardiac tissue at implant. See also passive fixation lead . Of short duration. In pacing, the acute phase occurs immediately post-implant.
Acute thresholds are thresholds taken during the first weeks after implantation of a new lead.
It is usually due to polarization effects. The portion of the pulse generator's timing cycle during which the pulse generator can sense and respond to intrinsic cardiac activity. The alert period follows the refractory period and ends with the next sensed or paced event. If the device is programmed to an inhibited or triggered mode, intrinsic activity sensed during the alert period will inhibit or trigger the pulse generator, respectively. Note that in dual-chamber devices, the atrial and ventricular sense amplifiers have separate alert periods and the ventricular alert period in such devices includes a portion of the AV delay.