You are just seeing the background noise, which you are picking up from the leads, grounds, and maybe your power supply. If you are connected to a person, that person is just an antenna for all of that background.
Heart rate is approximately 1Hz by comparison. Your scan width is way too narrow at this point. Later you can trigger on the EKG QRS complex, but first you have to find the pulse. Try something that will capture a 1 Hz signal. It appears you are set on 10 mS per division. Go to 500 mS per division. You also need to get the peaks on scale for your oscilloscope.
John