Yet again I’m indebted to Arron Pearce for my ECG of the month. This one was recorded from a 72-year-old male with chest pain. What I’m interested in is the rhythm and any possible conduction disturbances. Please provide as much detail as you can.
The format of the recording is such that every group of three leads shows the same 2.5 seconds of ECG. The lead II strip at the bottom is a 10-second serial recording.
Dr Dave Richley
Lovely rhythm challenge, again.
Looks to me like a bigeminal rhythm — sinus beats followed by PACs and PVCs, in an alternating pattern.
R1, 5, 9, 13, 17 = PACs
R2, 4, 6, 8, 10, 12, 14, 16 = sinus beats
R3, 7, 11, 15 = PVCs
The PACs conduct with LAFB — maybe due to phase 3 block in the LAFB. We can tell these are atrial beats due to the slight distortion of the T waves of the preceding sinus beat. I cannot reliably see any such distortion preceding what I think are PVCs, so I can reasonably assume they are not supraventricular.
The PVCs are not very wide (QRSd ≈ 120-130 ms) and have RBBB + LAFB morphology, with a rS in V4-6, suggestive of a left posterior fascicle origin.
Thanks, Onyinye. Some great comments there. I’m not sure I agree with you 100% but then I’m not completely certain that I’ve got it right either. I think I’ll need to study it very closely.