Reading the ECG: Rate and Rhythm

What this deck covers

Reading the ECG: Rate and Rhythm in twelve illustrated clinical cases with worked explanations – case presentations built around clinical images, radiology, teaching illustrations and real laboratory data, with the reference range beside every value a case quotes. This visual, data-interpretation style of practice suits candidates preparing for MRCPCH AKP in particular, alongside Saudi and Gulf licensing examinations such as the Arab Board, DHA and OMSB. Each case gives you a clinical vignette, four options, the correct answer, and an explanation of why each of the other three is wrong.

The twelve cases, in order

1. A strip, and a rate to work out
2. Every interval looks too long
3. Complexes that look too small
4. A rate that will not stay still
5. Deciding whether the rhythm is sinus
6. P waves and QRS complexes, marching
7. A wild trace, and a comfortable child
8. An extra beat, and then a pause
9. Upside down in one lead only
10. A newborn heart rate of 150
11. An irregular pulse with a pattern
12. Ten seconds, and a normal trace

What this deck teaches

• Read the corner before you read the trace. Paper speed and calibration set the two scales everything else is measured against, and both are printed on the trace. Half standard halves every voltage; 50 mm per second doubles every interval.
• 300 over the large squares. At the standard speed each large square is 0.2 seconds. The method assumes a regular rhythm, because it measures one interval and multiplies it up.
• Normal rate is age-specific. A newborn sits between about 110 and 160 at rest. The commonest way a well baby is investigated is an adult range read onto a child.
• Sinus is a P axis, not a P wave. The node sits high in the right atrium, so its P wave is upright in leads I and aVF and inverted in aVR. A P of any other direction started somewhere else.
• Regular and regular is not related. Two rates can each be perfectly regular while nothing conducts between them. Only a constant P to QRS distance shows the atria are driving the ventricles.
• Early is ectopic, late is escape. The timing of the extra beat is the finding. The pause that follows it is the consequence and separates nothing.

Exam pearls from this deck

• 300 over the large squares, and only while the rhythm is regular.
• If everything is long, suspect the paper before the patient.

The twelve worked cases in this deck, with the images and the full explanation of every option, are part of Pediatric Case Review membership. See what is included, or start with the free Pediatric Exam Review Sets.

More from this system: all cardiology illustrated case decks · cardiology board questions for bank-style drilling · the free Pediatric Exam Review Sets · pediatric reference values.