5-Wire Telemetry. Which lead tracing do I interpret?

[winzer]

I'm a novice at reading telemetry strips. I'm mostly self taught but also took an intro course. If given a given 6 second strip, I'll analyze for about half a minute and I usually get the interpretation right. But my question is this, on a 5-wire telemetry, what lead am I supposed to interpret and WHY?

I've searched forums and there seems to be emphasis on lead placement...I don't need to know about WHERE to place the leads. I'm not concerned with 12 lead interpretation either, I'm not responsible for 12 lead stuff on my unit (yah yah, I know it's "good to know" but that's not what I'm asking). I just want to know why a tracing from Lead I looks quite different than a tracing from Lead II.

Yesterday, I saw SVT on the monitor of a telemetry patient and this was reading on lead II. Switched it to lead I and it suddenly looked like VTach?

1) What lead should I read on a 5-wire telemetry?

2) Why does the tracing look so different from Lead I vs Lead II, etc?

Any input would be appreciated.

[Mel24522]

Lead II will not show ST elevation. We are told to measure in lead II but monitor in lead III.

[offlabel]

If you can follow II and V5 simultaneously, you'll pick up nearly 90% of potential ischemic events.

[vermillionsky]

For a 6 second strip, we normally look at Lead II on the top and V1 on the bottom. This is because they are like "mirror" images of each other. Sometimes you get poor amplitude on your two main leads so you can switch to your other leads to get a better view, or if for some reason the monitor is picking up too much noise in one lead only.

[offlabel]

Lead II will not show ST elevation. We are told to measure in lead II but monitor in lead III.

Re-reading this thread, just wanted to point out that lead II absolutely will show ST elevation during an ischemic event involving the RCA