This is the discussion for 52 year old male CC: Seizure. Be sure to check out the backstory!
We had lots of great comments for this case, and as always many of you were right on target.
Let's take a look at the initial 12-Lead:
We have a narrow complex tachycardia at 180 bpm, with some very subtle P-waves best seen in the lateral precordials. Given the patient's age, it is difficult to say whether or not this rhythm is sinus in origin or some other tachyarrhythmia.
Dr. Marriott's advice when you don't see obvious P-waves is to,
Cherchez le P on let T!
In case you don't speak French, this means to search for the P-wave on the T-wave. So I've marked up the initial 12-Lead to help highlight the atrial activity:
The P-waves in the limb leads, especially lead II, are bizarrely tented and give rise to what looks to be a large T-wave.
In this case the paramedics were not certain as to the etiology of the tachycardia. They established an IV, administered a fluid bolus, and attempted vagal maneuvers; all of which resulted in no change in the rate or the rhythm. They then administered 6mg of adenosine via rapid IV push and witnessed a "conversion" to the following 12-Lead:
At this point the patient's initial rhythm becomes obvious. P-waves are now clearly distinct from the T-waves. They have retained their bizarrely tented appearance and the PR interval appears to be unchanged.
Given these findings it is likely this patient was experiencing an inappropriate sinus tachycardia.
As many of you noted, the situation surrounding this patient's seizure seemed suspect. While the patient adamantly denied any drug use, the ED suspected a stimulant was behind the patient's seizure and tachycardia. However, the patient became lost to follow-up and the cause of his tachycardia remains unknown.
- Given a narrow complex tachycardia of unknown origin, do you feel it is appropriate to try an adenosine bolus?
- Would this patient have benefited from a benzodiazepine?