Strip 22

sinus rhythm with conduction disease


First Glance:

From across the room it looks like a slow regular wide-complex rhythm.

Discussion:

It’s clearly regular, and the lower trace shows lovely P waves. The lower trace is marked as a ‘V’ lead, and with the biphasic positive -> negative P before every QRS this is most consistent with a placement in V1 or V2 (if we assume this is a sinus rhythm). So if we assume this is a septal lead, then with that morphology this is likely RBBB. The PR interval is long, @ ~320 ms, for a slam-dunk first degree block.

Notice that the V lead shows one or two mm of ST depression, but the voltage calibration is at 200% so it would be hard to know whether this is significant from this lead alone.

The rate is in the mid 50’s. Some folks call this bradycardia, some don’t.

Final Impression?

Sinus borderline bradycadia with first degree block and RBBB.

Management implications:

A 12L would be good to evaluate for possible ischemia, otherwise there is not much here to suggest specific acute pathology. The combination of a first degree block (AV node disease) and a bundle branch block (conduction pathway disease) implies significant conduction disease.

 The Take-home Point:

Jack up the gain to see the P waves.

The atria confirm your rhythm diagnosis. See how much easier it is to see the P waves at 200%? If the gain on the lower lead were at 100% it would be difficult to differentiate this from an accelerated idioventricular rhythm, or junctional rhythm with aberrancy.

 

 

1purple_starOne star strip. Students should identify the rhythm correctly.

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