Heart Transplant: Atrial ‘Parasystole’

Report:

Top strip:

Sinus rhythm 86/min

Short PR interval 0.10”

Sinus rhythm (non-conducted) 76 - 78/min

Atrial pseudofusion beat (middle of the strip)

Bottom strip:

Sinus rhythm 89/min

Short PR interval 0.10”

Sinus rhythm (non-conducted) 89/min

Comment:

This is not a true atrial parasystole, since a surgical suture line separates the donor from the recipient atria. In the bottom strip, the two rates are virtually identical, with two P waves preceding every QRS complex. It may well be an accrochage, despite the obvious lack of any electrical connection.

The connection across the suture line between the atria is sometimes (up to 10% cases) re-established, but remains uncommon42.

In the top strip, the slight but definite sinus arrhythmia contrasts with the relative fixity of the (conducted) sinus rhythm of the denervated donor heart. The donor heart rate is capable of changing, but not in response to direct neural stimuli. Come to think of it, it had no capacity for sinus arrhythmia even before it was explanted – the donor would have been brain-dead.