Ross Brawn revealed on Wednesday he missed the recent Spanish grand prix to have checks on his heart.
After handing over to his Mercedes deputy Nick Fry in Barcelona, fellow Briton Brawn is back in action as the team boss in Monte Carlo.
Rumours hinted there was more to the story, but Brawn insisted to a German newspaper earlier on Wednesday that he was simply advised by doctors to take the weekend off after a night in hospital for checks.
He then told reporters in Monaco his symptoms had been "arrhythmia", or an irregular heartbeat, insisting he is "back to normal now".
Brawn, 57, joked the heart problem was triggered by watching an exciting football game on television.