You have been asked to review a 50-year-old female who has collapsed at work.
a) What are the abnormalities on the ECG? (25 % marks)
b) What is the rhythm? (25 % marks)
Narrow complex tachycardia, rate around 300bpm
Absent p waves
ST segment depression V4-V6
Atrial flutter with 1:1 conduction.
Many candidates appear to have examined the ECG, drawn a conclusion and then retrofitted findings to support that. Confabulation in answers was common. Acceptance in marking was made of relatively amorphous answers (e.g. "anterior" as opposed to specific leads) but even with this, lack of specificity was common. Many candidates ignored the highly pertinent history that was given, showing a lack of clinical context/Bayesian thinking.
This image was shamelessly stolen from LITFL. It is a rapid (rate of 300) sinus tachycardia with some ST segment depression which likely represents some degree of demand ischaemia. The only other thing this could be is a super-rapid AVNRT with orthodromic conduction.