In a patient with an accessory pathway that conducts only retrograde, which ECG finding would be expected during normal sinus rhythm?
- A Short PR interval
- B Delta wave
- C Normal PR interval and QRS ✓
- D Prolonged QT interval
Correct answer: C. Normal PR interval and QRS
Explanation
An accessory pathway that conducts only retrograde does not pre-excite the ventricles during sinus rhythm. Thus, the PR interval and QRS remain normal. A short PR and delta wave occur only with antegrade conduction over the pathway, as seen in Wolff-Parkinson-White syndrome.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.