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ECG of the week #10: 85yo weak/dizzy – what’s the cause/treatment of bradycardia?

Test yourself with this week’s ECG case. Then scroll down for a structured step-by-step interpretation and clinical pearl.

Clinical Scenario

An 85 year old female, with no cardiac history and on no rate-controlling medication, presented with 2 days of weakness and dizziness

ECG

Question

What’s the cause of bradycardia, and will ACLS treat it?

ECG Analysis

H: sinus bradycardia with a junctional escape on the 5th beat
E: normal intervals
A: left axis with inferior Q
R: early R wave V2
T: low voltages
S: inferior convex STE with reciprocal STD aVL, anterior STD, hyperacute T in V6

Answer

= bradycardia secondary to infero-postero-lateral Occlusion MI
cath lab activated: 100% circumflex occlusion
first trop 43,000 and peak 147,000

Clinical Pearl

1. ACLS is designed for primary bradycardia from conduction disease, not bradycardia secondary to a reversible cause. The circumflex artery perfuses the SA node, and the right coronary perfuses the SA and AV nodes. So circumflex or RCA occlusions can cause bradycardia, often with infero/postero/lateral STE/hyperacute T waves that do not meet STEMI criteria
2. It is common for ACS to present without chest pain in elderly female patients

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