If I showed you this picture would you know where you are?
Probably not, but what about this one, taken about an hour away?
Most probably recognize the Alamo (for the record the bird is a Black-capped Vireo, a species that breeds only in central Texas). Can you tell I recently attended the CORD conference in San Antonio?
What does that have to do with today’s EKG?
Well, let’s start with rate. It looks REAAAAAALLLLLLLLLLYYYYYYYYYYY slow. If we use the Count the Complexes and Multiply by 6 trick we get a rate in the 20’s, which is what the PCP did when he sent this asymptomatic patient in. But is that really what the rate is? What’s missing on this EKG? There’s only 6 leads notated on the EKG to orient us to where the tracing refers to, there should be 12. Furthermore, if we look carefully we notice the standard is twice as wide as it ought to be.
Why did the computer in the EKG decide to run it half speed? No idea, but make sure you recognize it when it does.
The rate therefore is double what a gestault glance would suggest, in the upper 40’s (as read by the computer interpretation). There are P waves so it is in fact a sinus brady, just not the severe one initially suggested. When corrected for the EKG being run slow the QRS complexes look fairly normal, as are probably the ST segments we see (but note of course that we don’t see the chest leads at all!).
The take-home from this EKG is always ask if a situation makes sense. It would be odd for a patient to be completely asymptomatic with a heart rate in the 20’s. We haven’t talked about always including a glance at the standard in your interpretation of an EKG but honestly a person should probably do that, at least until it becomes second nature to notice it. The other thing that an EKG like this reinforces is that when you get a call about an abnormal EKG from an outside site it may be worth asking them to fax it to you prior to making the patient invest in a trip to the ED and then be very frustrated when you tell them that they’re fine.