5th November 2021

A 72-year-old lady with a history of ischaemic heart disease presents to her GP having suffered a momentary loss of consciousness

A 72-year-old lady with a history of ischaemic heart disease presents to her GP having suffered a momentary loss of consciousness. She believes she has fainted only for a few seconds. She has not hit her head. A collateral history from her daughter suggests she went very pale prior to the attack. There was no seizure-like activity during the attack. The episode was not related to a change in posture. Luckily, the GP had suggested a 24-hour ECG monitor at their previous consultation. This revealed intermittent complete heart block. What is the most likely cause of this lady’s transient loss of consciousness?

Select the SINGLE most appropriate option from the list below. Select ONE option only.