CASE 05 • FREE SAMPLE
A broad-complex clue
A 66-year-old man with hypertension has an incidental broad QRS complex. Compare V1 and the lateral leads.
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?
Right bundle branch block
Systematic interpretation & clinical correlation
QRS duration ≥120 ms with rsR′/rSR′ morphology in V1–V2 and a broad terminal S wave in leads I and V6 is typical complete RBBB. Secondary ST depression/T-wave inversion in V1–V3 can be appropriate discordance; concordant or disproportionate ST changes require evaluation for superimposed ischaemia.
QRS duration ≥120 ms with rsR′/rSR′ morphology in V1–V2 and a broad terminal S wave in leads I and V6 is typical complete RBBB. Secondary ST depression/T-wave inversion in V1–V3 can be appropriate discordance; concordant or disproportionate ST changes require evaluation for superimposed ischaemia.
Immediate approach / management
Determine whether RBBB is new and whether symptoms suggest ACS, pulmonary embolism, myocarditis or advanced conduction disease. Isolated chronic asymptomatic RBBB generally needs no treatment. Syncope with bifascicular disease or evidence of intermittent high-grade AV block requires urgent rhythm evaluation and may require pacing.
Determine whether RBBB is new and whether symptoms suggest ACS, pulmonary embolism, myocarditis or advanced conduction disease. Isolated chronic asymptomatic RBBB generally needs no treatment. Syncope with bifascicular disease or evidence of intermittent high-grade AV block requires urgent rhythm evaluation and may require pacing.
High-yield ECG pearl
Do not call the expected right-precordial ST-T discordance “ischaemia” without considering the bundle-branch pattern.
Do not call the expected right-precordial ST-T discordance “ischaemia” without considering the bundle-branch pattern.
ECG source/licence: Wikimedia Commons file page.