The implant including an elongated tubular body, having at a first end a releasable device connected to an installation lead, and at a second end a member for anchoring to a heart wall, the tubular body housing a frame supporting an electronic unit. The implant further comprises an accelerometer. This accelerometer comprises a piezoelectric blade extending in cantilever from an embedding section of the frame, in a direction going from the first end to the second end.
