Emergency physicians have a large tolerance for uncertainty. We have a cheerful contempt for folks who come down to the ED and can’t seem to make a decision until every last lab value is back. That’s not who we are. However, sometimes you just don’t know what to do in a situation and the pressure to act builds up like lava in a volcano with the cone tied shut. This was one of those times.
The child was an 11-year-old female with an abscess on her buttock. She’d been seen 4 days prior and was started on bactrim but the abscess continued to enlarge. It’s time for an I & D. So far, so good, this seems straightforward. She hasn’t been NPO for the requisite time to sedation, so you leisurely proceed through the history and physical. Everything seems OK until you ask if there have been any prior problems with anesthesia. Funny you bring that up, you’re told. She had her tonsils out about a month ago. Before the procedure she had an irregular heart rate. They went ahead and did the procedure. Mom says her irregular heart rate improved during the anesthesia. But they were told to get it checked out by a cardiologist. In fact, they have the appointment scheduled. It’s for next week.
In other words, they don’t know what it is yet. You probe a little more. The child has been completely asymptomatic all her life. No palpitations, no chest pain, no fainting or spells. She runs around like every other child. There’s no family history of sudden death or dysrrhythmias. There’s no history of deafness (associated with one of the familial prolonged QT syndromes). The child’s had no recent illness to suggest carditis. In fact, except for the abscess, she’s the picture of blooming health.
You examine her. There’s the abscess on her backside, no question that she needs an I & D. Her heart rate is irregular, but with no murmurs or gallops, she has strong but irregular pulses and the rest of her exam is fine.
OK, this is getting interesting. You order an EKG and while you’re waiting, the nurse comes in to start her IV and hooks her up to the monitor. There are premature ventricular contractions (PVCs). Lots of them. In fact, every other beat is a PVC. They appear to be unifocal. The EKG is done and confirms what you saw on the monitor, the kid has bigeminy but is completely without symptoms. So what do you do with that? Is it safe to sedate her in the ED to drain this abscess? What is the sedation risk for a kid with PVCs, an otherwise normal exam, and no symptoms?
A quick search gives you some sense of what to. Alexander and Berul (Ventricular arrythmias: when to worry. Pediatr Card 2000;21:532-41) say that benign patterns usually exhibit: normal sinus rhythm repolarization, normal ventricular function, and no family history of early mortality. OK, she seems like she meets those criteria. Each PVC is not preceded by a P wave, and the P-P interval between PVCs is about the length you would expect if she had two sinus cycles back to back, suggesting that the pause after the PVC is fully compensatory – the sinus mechanism does not appear to be thrown off by the extra beat. Nasty PVCs are more likely to be multifocal, be grouped as two or more in a row (basically, non-sustained V-tach), have an R on T phenomenon (where the PVC starts on the T wave of the preceding beat), or be associated with underlying heart disease. Nothing here to suggest that. Benign PVCs tend to improve with tachycardia, such as that associated with exercise.
You’re still not feeling comfortable. You phone the pediatric cardiologist on call. Is it OK to sedate this kid? He’s reassuring. This child most likely has benign congenital bigeminy. Her normal exercise tolerance, lack of symptoms and otherwise normal exam are good news. He tells you to proceed, monitoring her just like any other patient you sedate. You decide to use Ketamine, feeling that the increase in her heart rate might suppress her PVCs. First, you give a dose of atropine – sure enough, the PVCs are far less frequent as her heart rate climbs. She tolerates the sedation beautifully, the abscess is drained and packed and the child is sent home with wound care follow-up arranged. And now that her sedation is over, your heart rate also comes down to normal.
Amy Levine, MD, is an assistant professor of pediatric EM at UNC Chapel Hill