Chapter 3 Test — Normal ECG Blueprint

The 12-lead ECG shown was recorded during a routine health check in an asymptomatic 30-year-old man. Which single feature on this tracing is the most reliable confirmation that the rhythm originates in the sinoatrial node?

A 22-year-old man has a regular narrow-complex rhythm at 68/min. Every QRS is preceded by a P wave with a constant PR interval, but the P wave is inverted in lead II and upright in aVR. Which is the correct interpretation?

The PR intervals from ECG recordings of four patients are listed below. Which patient has a normal PR interval?
Patient 1: 0.19 s | Patient 2: 0.30 s | Patient 3: 0.23 s | Patient 4: 0.10 s

What does the PR segment on an electrocardiogram (ECG) indicate?

A 40-year-old woman has a regular sinus rhythm at 75 beats/min. The QT interval measured in lead V5 is 440 ms. Using Bazett's formula, her corrected QT (QTc) is approximately:

The figure shows the standard intervals and segments of the ECG. When measuring the amount of ST-segment elevation or depression, which part of the tracing should be used as the isoelectric (baseline) reference?

A healthy 45-year-old man has a routine ECG showing small negative deflections at the start of the QRS complex in leads I, aVL, V5 and V6. Which set of features confirms that these are normal septal q waves rather than pathological Q waves?

An asymptomatic 28-year-old woman has a pre-employment ECG. Everything is normal except an inverted T wave in lead V1; V2 to V6 show upright T waves and there are no ST changes or Q waves. What is the correct interpretation?

On a 12-lead ECG the QRS complex is positive in lead I, negative in aVF, and positive in lead II. Which of the following is the correct interpretation of the frontal QRS axis?

A 60-year-old man presents with palpitations. His ECG shows a negative QRS complex in both lead I and lead aVF. Which statement is correct?

The figure compares R-wave progression across the right precordial leads. A 68-year-old man's ECG matches the middle panel — persistently small R waves that fail to grow across V1 to V4. Until proven otherwise, this pattern most commonly indicates:

On a normal 12-lead ECG, the precordial transition zone — the lead in which the R wave and S wave are of approximately equal amplitude — is usually located at:

A 55-year-old diabetic man presents with 40 minutes of central chest pain. His initial 12-lead ECG is completely normal and the first troponin is undetectable. What is the most appropriate next step?

A 64-year-old hypertensive man, non-compliant with his medications, presents with sudden tearing chest pain radiating to his back. BMI is 21 kg/m². His ECG is normal and cardiac enzymes are not elevated, but the chest radiograph shows a widened mediastinum. What is the likely diagnosis?

A 10-year-old asymptomatic boy has a routine ECG before minor surgery. Lead V2 is shown; leads V1 and V3 look similar, with no ST-segment deviation and no Q waves. The rest of the ECG is normal. The most likely explanation is:

A 22-year-old asymptomatic male athlete undergoes pre-participation screening. His ECG is shown. There is J-point elevation with notching and concave ("scooped") ST elevation in V2 to V5, with tall concordant T waves. There are no reciprocal ST depressions and no PR-segment depression, and a repeat tracing one week later is identical. The most likely diagnosis is:

The figure compares four ST-segment elevation morphologies. Which single feature most reliably favours acute STEMI over benign early repolarisation?