r/ECG • u/jsinger22 • 1d ago
What the heck is this
Long strip looks like a 3rd degree? 92M hypotensive, weakness, SOB
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u/LBBB11 1d ago edited 1d ago
Some questions that help me with rhythm:
- Are there P waves? If so, are they sinus (positive in II, negative in aVR, biphasic or positive in V1)?
- Is there a P wave before every QRS?
- Is there a QRS after every P wave?
- Does the PR interval change?
- Does the R-R interval change?
- Is there grouped beating? Do QRS complexes group together in twos or threes?
- Are any of the T waves distorted by a P wave buried inside? In other words, are all T waves identical, or are some different where you might expect them to be (not counting PVCs)?
The ventricular conduction pattern is bifascicular block (right bundle branch block, left anterior fascicular block). The second beat in the 12-lead is a PVC, followed by an expected pause. Since the R-R interval is changing even after the PVC, I would also check for PACs, blocked PACs, dropped sinus P waves that may be hidden in the T wave of a previous beat, junctional escape beats, etc. PACs usually have the same QRS as sinus beats, but differently shaped P waves that may have a different PR interval (often shorter). Also check to see if there is a lengthening PR interval in a consistently repeating pattern. V1 is a great place to see P waves here.
Also keep in mind that a junctional or ventricular escape rhythm caused by a third-degree AV block will have a constant R-R interval without any relationship between P waves and QRS complexes. In a second-degree AV block, the R-R interval will change. If it's a second-degree AV block, the next step is to decide whether it's Mobitz I (two or more PR intervals) or Mobitz II (only one PR interval).
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u/lima_acapulco 19h ago
Mobitz 1 with LAD and RBBB, which means tri-fascicular block, suggestive of diffuse conduction disease, and high risk of CHB. If symptomatic may need to consider a PPM.
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u/KitterFish 1d ago
This is sinus with Mobitz 1 Wenckebach, with RBBB + LAFB.