As with Dr Echt's design, power constraints mean that this approach can be used only for pacing.

ECONOMIST: Case history

This method also has the advantage that the placement of the receiver allows the pacing of the heart to be very precisely controlled, says Dr Echt.

ECONOMIST: Case history

They have names like Bullet Tooth Tony (Vinnie Jones) and Brick Top (Alan Ford), and they converse in the artful patois that Ritchie continues to sell as echt.

NEWYORKER: Snatch

It is similar to Dr Echt's leadless pacemaker, but it uses electromagnetic induction, rather than ultrasound, to stimulate a small implanted receiver, which in turn stimulates the heart.

ECONOMIST: Case history