“Why should I care about R wave progression, I am only a medic and I should only be able to diagnose STEMI”. These words pierce right through me like a knife. But, people only see what they know and if you don’t study this then you are going to potential miss some bad pathology.
This is from Dr. Smith’s ECG blog. If you are not familiar with Dr. Smith, he is a leading expert on difficult ECG’s and a personnel idol of mine!
“If the mean R-wave amplitude from V2-V4 is less than 5 mm, then it is almost certainly MI. If greater than 5 mm, it is probably BER (benign early repolarization). A cutoff of 5 mm gives a sensitivity for MI of about 70%, but a specificity of greater than 95%.”
STILL DON’T THINK IT’S IMPORTANT? Well keep reading baby birds.
Before we start talking about “poor R-Wave progression”, you must first define what “normal” R-wave progression really is. Normal R-wave progression is where normally, from lead V1 to lead V6, the pattern is that of a change from the S wave being prominent to the R wave being prominent. So when looking at V1 you should have a mostly downward deflecting axis and in V6 you should have a mostly upward inflecting QRS axis.
We should also notice how rS complex in V1 SLOWLY “transitions” from negative to positive in V6. This “transition” is called; yup you guessed it, R wave transition. There should be a gradual transition from negative to positive. So which brings up the next question, what is “normal”? We must define set criteria for normal. In the literature, definitions of poor R-wave progression have been variable, using criteria such as R-wave less than 2-4 mm in leads V3 or V4 and/or the presence of reversed R-wave progression defined as R in V4 <R in V3 or R in V3 <R in V2 or R in V2 < R in V1, or any combination of these. So we can have either early progression or late progression. Now let’s look at some abnormal ECGs.
This would be an example of late R wave progression. Biphasic T waves and deep Q’s in the inferior leads. This is an anterior wall MI. See the importance?
Yet another old anterior MI!!
See a pattern here? So what is the differential for poor R wave progression?
- Left bundle branch block
- Left anterior fascicular block
- Wolff-Parkinson-White syndrome, certain
- Right ventricular hypertrophy (especially that associated with chronic pulmonary disease)
- Left ventricular hypertrophy
- Anterior MIHmmmmmmm! Does this seem important now?
What is the above ECG? See delta waves? Loss of R wave progression? You guessed it! WPW.
What about this one? Very late transition and RsR’ in V5. This is a LBBB.
Knowledge is power. By learning the art of 12-lead we can better clinicians and instead of looking at that 80 year old female pt with your paramedic eyes and signing that refusal, you might be able to make a lot better judgment call on not just transporting but a lot where you are transporting to. My next post will be on tall R waves in lead V1 and stay tuned for my podcast on this topic just in case you hate reading.