If you are using the Go Direct® EKG Sensor (GDX-EKG) make sure you are using the EKG channel.
If you are using the EKG Sensor (EKG-BTA) you should update to the most recent version of Logger Pro or LabQuest App. The most recent versions of these two programs automatically filter data collected with an EKG Sensor.
If you are using an older version of Logger Pro, you can open an experiment file that has been set up to automatically filter the data. There are two experiment files that will work. To find the files
1. In Logger Pro, choose Open from the File menu.
2. Open either “Analyzing Heart EKG” in the “Human Physiology w Vernier” folder or “Monitoring EKG” in the “Biology w Vernier” folder.
If problems persist, check the following:
There are several things that can increase the noise in an EKG trace. Most of these issues can be addressed using proper electrode placement and placement of the sensor. Software filtering can also be used to clean up a noise signal as well. See the instructions below.
Is an EKG trace visible? If the QRS complex (big spike) in the EKG trace is not visible then there is either a problem with the EKG sensor or a problem with the subject. To test the EKG sensor, collect data while shaking the leads when they are not attached to the subject. You should see a change in the trace. If you do not see a change, something could be wrong with the leads or the sensor. Call technical support.
In a few cases (less than 12%) the subject’s skin may not be conductive enough to pick up a good EKG trace. Abrasive / conductive electrode gel and clinical grade EKG electrodes may need to be used in this case. The easiest way to test this is to record an EKG from another individual. If you get a good EKG from another subject then skin conductivity is the problem.
If the EKG trace is visible but is noisy there are several things that you can do to decrease the noise.
If you are using a LabQuest or laptop computer, use the battery power (remove the AC adapter). This should decrease the noise.
Let the electrodes sit on the skin for 1-2 minutes before you begin recording. This will increase the strength of the signal.
Place the grounding electrode on the ulnar process of the wrist. If you are recording from the chest, place the grounding lead on the clavicle. This will increase the strength of the signal and should decrease any noise.
Do not place the EKG sensor near computers, cell phones, power outlets or the LabQuest. The EKG sensor is not shielded and can pick up electronic interference and noise. The best location for the EKG sensor is on the subject’s lap or knee during a recording.
If problems persist, please contact Technical Support.