Code 3 for hypertension.
This is a 76-year-old female whose daughter called for a relatively sudden onset of weakness over the past hour. She speaks no English, and her daughter tells us that she’s been generally “fine” except that over the past week when taking a walk she’s been experiencing some mildly increased SOB that subsides with rest.
Pt appears just a tad tired, but otherwise looks fine.
VS: BP 221/83, P 40, R 18, SpO2 94% RA
In a moment of candor, the fire captain says, “I’m not sure what’s going on, but I heard someone say something about a block.” He hands me this from their Zoll:
What do you think? What do you do?
So, it seems like most people have commented that this is a 3º AV block, which is what I was thinking when I looked at this first strip.
After some interrogation, her daughter tells us that the patient has a history of hypertension and breast cancer that was treated with a lumpectomy and chemotherapy a few years ago, which caused extensive heart damage, requiring the implantation of a pacemaker. She isn’t sure what kind of pacemaker it is, but she mentions that it only “came on sometimes” and does not think that it is constantly firing. She also mentions that the pacemaker was “adjusted” a month ago, but she has no details to offer.
Looking at the Zoll, I wonder if her pacemaker is firing.
We switch her to our LP12, and I’m a little disappointed (not that I wish people were sick, but you know what I mean). I was excited about the possibility of a decent call for a change, but this is turning out to be a bit anti-climactic. Here are a couple of strips, confirming what I half-suspected:
For those of you not familiar with the LP12, to limit distortion to the actual tracings, the default setting suppresses the pacemaker spikes, which are instead represented by the hollow arrows at the bottom of the strip.
It seems that the Zoll simply failed to detect the pacemaker firing, which, after a little research, is something that happens every now and then, according to Zoll themselves. (Probably the same situation with other monitors as well.)
And, here’s the cleanest copy of the 4 nearly-identical 12-leads obtained over 30 minutes:
It looks like there is intrinsic atrial firing at about 90 bpm without any conduction to the ventricles, which are paced consistently at pretty much exactly 40 bpm. I’m certainly no expert like Tom, who in his comments wondered about the possibility of a paced rhythm, but there are some who might say that leads II and III look like there’s concordant ST elevation (based on the positive terminal QRS deflections), whereas I feel that the first upward deflections are part of the T waves, rather than part of the QRS complexes.
VS: BP 212/102, P 40, R 18, SpO2 98% with oxygen 2L/min via cannula
It appears that the pacemaker is firing as intended without any apparent issues, other than the fact that the rate seems on the low side. I wonder if it’s intentionally set this way. And I wonder what pacemaker “adjustment” her daughter was referring to. We transport her code 2 with a saline lock, with the unopened pacing pads and the therapy cable on her lap. And a pair of shears in case I have to cut her shirt very quickly. (I hate cutting clothes if I can help it.) The ride goes without incident or any change in her condition. Her shirt survives. Her BP remains mostly the same.
We leave her at the ED, and a couple of hours later we bring someone else to the same hospital, which is coincidentally the area cardiac receiving center. I check with the original nurse, who says that the rep from the pacemaker manufacturer is in the room.
It’s not often we get to talk to these pacemaker reps. So, I go to meet her. She tells me that the patient has a dual-chamber demand pacemaker with a lower atrial rate limit of 80 bpm and a lower ventricular rate limit of 40 bpm. It was set up this way because the patient previously had occasional brady-arrhythmias due to the chemotherapy but did not require a pacemaker that was always firing.
So, it is thought that some time over the past week, with her atrium still firing normally, she lost her ventricular portion of the rhythm for some reason(s) out of many possible reasons. And now her pacemaker is functioning as intended. Since it’s now the only way her ventricles are contracting effectively, 40 bpm – previously the last-resort rate – is too low. The rep adjusts it upwards to 60 bpm.
Interestingly, her BP is now in the 170s/90s range without any other interventions. No one has an answer for that.
As of this writing, there is no other significant finding.
I didn’t start this blog to write call reviews, but this call is interesting to me in a few ways from a training perspective. We teach crews to do all this stuff but we don’t do a good enough job of teaching them to think about what they’re going to do before they do it. I shudder when I think about how many ways this call could have gone wrong if we didn’t figure out that it was a paced rhythm and not 3º AV block. Even though we’re writing about it now with the benefit of hindsight, I personally know crews out there who would have immediately given this patient Atropine or started transcutaneous pacing based on that very first Zoll tracing.
Please don’t misunderstand me – I’m certainly NOT knocking anyone who thought this was 3º AV block based on the first Zoll strip, because that’s exactly what I was thinking, and without the pacemaker spikes, that’s what it looked like. What I am concerned about is the fact that there are crews out there who would jump right into treatment, unnecessarily in this case, without first looking at a patient who is at most in very mild distress, and without diligently gathering as much relevant information as possible.
Furthermore, over the past 5 years or so, with more and more such tools as 12-lead, CPAP, capnography, etc. at our disposal, EMS is slowly but surely shifting toward a new paradigm, and it’s much more important for us to thoroughly obtain findings and assess our options. It takes some discipline to take that extra minute or two, that extra deep breath, to make sure we do things right the first time. The old way in EMS of providing treatment as quickly as possible based on a limited history and assessment, other possibilities be damned, is thankfully falling out of favor (but not quickly enough). Using Lasix for pneumonia is probably the best example, out of many, of this mindset.
Response to comments:
Regarding ST elevation, as Tom mentioned, the filters in monitor mode (3-lead, 4-lead, when not obtaining 12-leads) are set for different frequency ranges than in diagnostic mode (when obtaining 12-leads). As a result, ST elevation present in monitor mode may not be present in diagnostic mode. Anecdotally for me, every time someone has said “there’s ST elevation” on a call when looking at a 3-lead or 4-lead, I have yet to see it present on a 12-lead.