afib with RVR
First Glance:
From across the room it looks like a fast irregular SVT
Discussion:
We can see it’s fast. It’s clearly irregularly irregular. We examine the baseline in the longer pauses before the QRS and see nothing consistent with a P wave (although admittedly this is only two leads and the gain is down to 40%). This looks like afib with rapid ventricular response.
The monitor says 153 bpm, although the ‘pulse’ is noted as 90. What gives? The ‘pulse’ can be calculated by the monitor from either an Sp02 waveform or an A-line waveform. We don’t know which one it is coming from here. We do know, however, that almost half of these QRS’s are not registering as a pulse. This can be due to artifact or poor pickup, but it would not actually be a surprising finding in this patient.
The atrial kick can contibute from ten percent to over a quarter of the diastolic filling, so the combination of severely decreased filling time (as seen in a brisk tachycardia) plus loss of atrial kick (as in atrial fibrillation, or any rhythm paced by the AV node or below) means that this person might not actually have much stroke volume for a large portion of their ventricular contractions.
There is a little ST elevation in the V (upper) lead. From the V lead it looked possible that the complexes were on the wide side, although examining lead II below makes me think that apparent widening is just an elevated initial ST segment.
Final Impression?
Afib with RVR @ 153 bpm.
Management implications:
Rate control. Patients ill enough to have atrial fibrillation usually do not do well taching along above 150 bpm. Get a 12L to evaluate for ischemia.
The Take-home Point:
The rate is not the only thing that makes rapid afib a potentially compromised hemodynamic state. The loss of the atrial kick can have significant consequences for many patients- especially those with already poor diastolic filling (LVH, mitral stenosis, etc) or borderline cardiac outputs (severe cardiac disease of almost any type).
One star strip. Students should identify the rhythm correctly.