Thirty questions on the electrocardiogram from first principles: what the cardiac cell does, how the impulse travels, what the leads are actually measuring, and what every wave, segment and interval on the tracing represents. The five phases do not run in numerical order — rest is phase four, and the upstroke that follows it is phase zero — which is why they are asked as a sequence rather than as a list. The same logic runs through the conduction system: each pacemaker has its own intrinsic rate, so a rate in the forties with no sinus activity tells you which one has taken over. Numbers are part of this lecture, unlike the rest of the course. The objectives say to determine heart rate and to measure and interpret the intervals, so the figures are the material. What the questions do is give you what you would actually have in front of you — the strip, the count, the interval in small boxes — and ask what follows from it. Eight complexes in six seconds is a rate; seven small boxes of PR is a prolonged interval. One thing worth carrying out of here: an electrocardiogram cannot tell you whether your patient has a pulse. It shows electrical activity, and electrical activity without a pulse is a real and lethal state. Built from the slides, with the recording queued behind the exams that come sooner; every question cites the slide it came from.
Answers reveal only after you choose. Your score and a breakdown by objective appear at the end, with a review of everything you missed.