A Regular Atrial Fibrillation

A patient s/p AVR. What is this rhythm?

Image Case

This is regular wide QRS complex rhythm (~68 bpm) with no discernible P waves. It has a RBBB pattern (qr in V1) and it does not fit the RBBB-VT criteria for VT wich could either be monophasic R, QR and the rabbit-ear morphology. Thus, this is atrial fibrillation, complete heart block, accelerated junctional rhythm with bundle branch block (likely RBBB). A pacemaker was later implanted.

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Can atrial fibrillation (AF) be regular?

Adult with h/o HTN, DM, dyslipidemia, s/p cabg, s/p mvr, tvr c/o fever What is the rhythm?

Image 1

This is a regular  wide QRS rhythm at a rate of about 60 bpm  with no discernible P waves. There is right bundle branch block or RBBB (rsR in V1 and wide S in lead I) and left anterior fascicular block. 

A rhythm that can generate regular wide QRS rhythm with no P waves is AF with ventricular pacing. There are no pacer spikes seen (also this pt really has no pacemaker). 

Atrial flutter can also generate a regular rhythm with wide QRS complexes in the presence of a fixed bundle branch block or or aberrancy. In this case, it is difficult to appreciate the typical flutter wave morphology even with a 12 lead.

So, a likely interpretation is atrial fibrillation with complete heart block with a junctional escape rhythm with a right bundle branch block. The typical RBBB morphology is suggestive of supraventricular activation of the ventricles.



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