Alarm Clock Cardiology

Its 0630. My alarm clock starts to beep.

Now it’s 0632. It is still beeping. But I ignore it in favor of studying the speckled pattern on the ceiling. Sure, it might not be the best ceiling in the world, but it’s definitely up there. (Yup!)

By 0635 my alarm clock is screaming that if I don’t get up soon I will be late for the start of my 0700 shift. But I still don’t move. Its not that I can’t get up. I just don’t want to get up.

Anyone ever been there? Just because my alarm is going off doesn’t mean I am going to be a responsible adult and get up right away every time.

In school it is drilled into our heads — treat the patient not the monitor. But what does that even mean? Let me break it down with the five cardiac arrest rhythms. To do this I need you to imagine that your alarm clock is the SA node/primary pacemaker, and you are the heart muscle.


Normal Sinus Rhythm

On a good day your alarm clock beeps, you get up, and all is right in the world. As I am writing this my heart rate is 62bpm in a normal sinus rhythm. So, 62 times a minute my SA node “beeps” and my heart muscle “gets up” by contracting. Perfect. Exactly what we want to be happening. Visible rhythm on the monitor with a palpable pulse.

Warner Bros

Pulseless Electrical Activity (PEA)

Have you ever slept through your alarm? Maybe you were sick or just over tired. It isn’t your clock’s fault — it can’t physically drag you out from under the covers and make you go to work. You have to do that part. Sometimes the pacemaker of the heart works flawlessly, but the actual muscle doesn’t respond. It might be sick or just plain worn out. This is when you will see a rhythm on the monitor, but your patient doesn’t have a pulse. (HINT: Now would be a great time to turn up the beats and get crackin’!)



Worse than sleeping through your alarm is when it never even goes off. Maybe the power went out, the battery died, or you set it for PM instead of AM. I don’t judge. Totally been there… multiple times. The bottom (flat)line is that without the stimulus of the alarm/SA node you/the muscle don’t get up. So you don’t get to work. You will never, ever, ever have a pulse with an asystolic rhythm. If you do, you are either magical, or your electrodes aren’t placed correctly.


Ventricular Fibrillation  (VF)

Have you ever been awake enough to know you were cold, but not awake enough to pull up the blanket and solve the problem? The whole night is miserable, and you are more exhausted when you get out of bed than you were when you got in. That is what happens to the heart during ventricular fibrillation. The alarm/SA node isn’t stimulating you/the heart muscle to contract, and instead you/the muscle are just there quivering. VF won’t have a pulse because even though the heart muscle is moving, it isn’t fully contracting, therefore it isn’t actually perfusing and doing its job.


Ventricular Tachycardia (VT)

Ever heard of a hypnagogic jerk? No, it isn’t some irritable person practicing hypnosis. It’s what happens when you are about to fall asleep, but suddenly startle and become wide awake again. Not because your alarm clock woke you, but because your body woke you. Ventricular tachycardia is like that, but on repeat. Ignoring the primary pacemaker (SA Node), the muscles of the ventricle take over instigating a rhythm. Sometimes VT has a pulse. Sometimes it doesn’t. Sometimes your patient is responsive. Sometimes they aren’t. It really is a jerk of a rhythm….

Unfortunately, when the alarm clock isn’t working at all (VF and VT) you might need someone to come dump a bucket of cold water on you to shock you into carrying on with life. As for me, by 0640 I decide that if I let my alarm carry on for much longer it might end up with laryngitis. So, I did the merciful thing and shut it off. (And I still made it to work on time!)