Control a servo from analog EKG Sensor

Hey I am struggling to write the code for a little project i'm working on. I want to code a matlab file to detect a stimulus from the EKG sensor which is an analog input and once it detects a certain value (person tensing) it will control the motor to fully extend hence operating my prototype. Any help is welcome big or small thank you. If you have done a project previously I would love to know how you got it working.