When a PCT finds all waveforms negative in Lead I, which limb electrodes should be checked?

When all waveforms are negative in Lead I, this indicates a potential issue with the electrode placement or connectivity for that specific lead. Lead I measures the electrical activity between the right arm and the left arm. Therefore, checking the left arm and left leg is crucial because the left arm is directly involved in Lead I, and the left leg can also influence the readings by affecting ground reference.

If the left arm is not properly placed or has a poor connection, it can result in a negative waveform in Lead I. Ensuring that the electrodes on both the left arm and left leg are positioned correctly and making proper contact with the skin will likely resolve the issue and yield a more accurate reading.

In summary, focusing on the left arm and left leg allows for troubleshooting and correction of any inaccuracies in the Lead I waveform, which is essential for monitoring and interpreting heart activity effectively.