This EKG was done on a healthy, active, young, man with palpitations.
+ EKG Interpretation
Dr. Ohlbaum's Explanation
Are there P waves? Yes. Is it regular? Yes. Is there a P before every QRS and a QRS after every P? Again, yes. So, it is sinus rhythm, and the rate is 95, so normal sinus rhythm. The P waves look normal. What about the PR? Now it starts to get tricky. Something changes midway thru the EKG. And when you look at the QRS complexes there is a difference between the first part of the EKG and the last part. The first 10 beats have a normal PR and normal QRS. But if you look at the rhythm strip you will see that starting on beat 11, as soon as the P ends there is an upsloping "something". You can see it in the V leads for the rest of the EKG as well. That is a delta wave making the PR short. And the QRS morphology changes (look at V2 and V3 where the changes happens). This is an intermittent WPW. It is a type B WPW because the QRS is negative in Vl and the delta is upright in the rest of the precordial leads.
This is sinus rhythm with an intermittent Type B WPW. Now to the palpitations. He is in sinus rhythm on the 12 lead EKG, but turn the page to see what happened on an event monitor when he was playing basketball.
This is an AV reentry tachycardia, the QRS is narrow so it is going thru the normal AV and back thru the accessory pathway (orthodromic) so it is narrow. The rate was really fast (close to 300), lasted about 90 seconds.
Life in the Fast Lane: AVNRT