CASE 02 • FREE SAMPLE
The irregular pulse
A 72-year-old woman has palpitations and exertional breathlessness. Pulse is irregularly irregular at 132/min.

Clinical questions
1. Interpret the ECG systematically.
2. What is the most likely ECG diagnosis?
3. What is the immediate clinical significance?
4. What should be done next?
1. Interpret the ECG systematically.
2. What is the most likely ECG diagnosis?
3. What is the immediate clinical significance?
4. What should be done next?
Atrial fibrillation with rapid ventricular response
Systematic interpretation & clinical correlation
Narrow-complex irregular tachycardia with no reproducible P waves, continuously varying RR intervals and a fibrillatory baseline: atrial fibrillation with rapid ventricular response. Look for pre-excitation if the ventricular response is extremely rapid and irregular, because AV-nodal blockers may then be dangerous.
Narrow-complex irregular tachycardia with no reproducible P waves, continuously varying RR intervals and a fibrillatory baseline: atrial fibrillation with rapid ventricular response. Look for pre-excitation if the ventricular response is extremely rapid and irregular, because AV-nodal blockers may then be dangerous.
Immediate approach / management
First determine haemodynamic stability. Shock, ongoing ischaemia, pulmonary oedema or altered consciousness attributable to AF requires synchronized cardioversion. If stable, treat triggers and choose rate or rhythm control according to duration, symptoms and substrate. Assess thromboembolic risk and anticoagulation; if cardioversion is planned and AF duration is >48 h or unknown, follow appropriate anticoagulation/TEE-guided strategy unless emergency cardioversion is required.
First determine haemodynamic stability. Shock, ongoing ischaemia, pulmonary oedema or altered consciousness attributable to AF requires synchronized cardioversion. If stable, treat triggers and choose rate or rhythm control according to duration, symptoms and substrate. Assess thromboembolic risk and anticoagulation; if cardioversion is planned and AF duration is >48 h or unknown, follow appropriate anticoagulation/TEE-guided strategy unless emergency cardioversion is required.
High-yield ECG pearl
The ventricular rate is not the whole diagnosis: instability, AF duration, stroke risk and the possibility of pre-excitation determine the next step.
The ventricular rate is not the whole diagnosis: instability, AF duration, stroke risk and the possibility of pre-excitation determine the next step.
ECG source/licence: Wikimedia Commons file page.