For each of the cardiac phenomena A–E, select the most appropriate option from the features of the electrocardiogram listed below

A. Option 5 A flat record. During asystole no ECG complexes can be detected.

B. Option 1 The T wave. The T wave marks the end of the ventricular depolarization that gives rise to systole.

C. Option 4 Depression of the ST segment. Depression of the ST segment is a sign of ischaemia during cardiac treadmill testing.

D. Option 3 The P–R interval. This delay allows the atria to contract before the ventricles contract.

E. Option 2 The P wave. Abnormalities in the P waves indicate atrial dysfunction