Getting Happy with Parker Pyne: The Case of the Rich Woman by Agatha Christie

Let's just hope for all our sakes we never get another opportunity
to go off on a tangent about body-switch comedies. (One never knows
in the Christieverse.) In this, the final story in the "Miss
Lonelyhearts"-esque section of the Parker Pyne collection, we
perhaps see our "heart specialist" at his most dastardly AND
brilliant.