R-on-P Bigeminy

Report:

Sinus rhythm 93/min

First degree AV block (PR 0.28”)

VEBs, bigeminal

Early transition (counterclockwise rotation)

Nonspecific ST/T changes

Comment:

The VEBs are easily recognised for what they are, with obvious dissociation from the preceding (“antecedent but unattached”) P waves, good rabbit ears and nonsense axis. In all but two leads they have QS morphology, but no inference can be made about previous infarction from that: QR or QRS would be required.

The VEBs are late, end-diastolic, and show well the sharply inscribed sinus P waves preceding them. So much for definitions of VEBs along the lines of “..no preceding P wave”124!

Despite the strategic placement of the P waves, the VEBs had practically no output and the patient’s pulse rate, at the wrist, appeared slow – half the actual rate. The bradycardia on admission was diagnosed by her GP, without an ECG. She did better with atrial bigeminy later (Fig 161a)

161a. The LAA is more easily recognised here. The VEB is like the ones before. Atrial ectopics have a reasonable P’R interval and narrow QRS – hence the better output. 162. Hypokalæmic 68 year old woman with “chest pain 5 days ago, shortness of breath now”. Lead V1 recording.