Abstract: An endocardiac lead of the type including a conductive spiral winding 2 placed inside a sheath 1 made of a flexible material being insensitive to body fluids. This spiral winding 2 is electrically connected to an electrode 3 intended for being brought into contact with the inner wall of the heart. The electrode 3 is hollow and accommodates along its centerline a deformable helix 6 intended for fastening the lead into the heart muscle. The inner diameter of the electrode 3 is smaller than the outer diameter of the undeformed helix 6. The helix 6 presents a sufficient longitudinal elasticity modulus for being retractable inside the electrode 3 with a mechanical deformation, while the helix will substantially recover its initial shape during its extraction out of the electrode and secure the electrode to the tissue. The helix 6 may be made of a nickel-titanium based alloy.

Abstract: Controlling a cardiac pacemaker wherein the cardiac pacing rate is controlled according to a measure of the metabolic demand. The average minute ventilation MV-8-0 is measured over the eight last breathing cycles (first one to eighth one), and it is compared with the average minute ventilation MV-8-1 over the previous eight breathing cycles (ninth one to sixteenth one), and it is determined that an effort phase is present when MV-8-0>MV-8-1, and that a recovery phase is present when MV-8-0<MV-8-1. These determinations are used to determine whether sensed changes in the ventilation correspond to transitions between the effort and recovery or ventilation gaps or artifacts so that the cardiac pacing rate is not decreased during an effort.

Abstract: A method for controlling the cardiac rhythm of a wearer of a dual-chamber pacemaker. A post-atrial atrial refractory period (PAARP) is defined. Any depolarization of the atrium that occurs during the PAARP is defined as pathological. An atrial-ventricular delay is not triggered in response to a pathological depolarization.

Abstract: A method for detecting and controllig endless loop tachycardia (ELT) of a heart being controlled by a cardiac pulse generator.A measurement is made of the VP time interval over eight cycles and of its maximum deviation which is compared with two threshold values.A modulation is applied to the atrio-ventricular delay and the following VP time interval is measured during the ninth cycle. The variation of the VP time interval is compared with the threshold values for determining whether one is dealing with an ELT or with a sinus rhythm.

Abstract: Endocardiac probe for a pacemaker, this probe is of the type comprising a helically wound lead (1) enclosed in a flexible sheath (2), with an electrode fitted on the tip of said lead, characterized by said electrode being formed of an annular piece (4) traversed by an attachment member (5-6) comprising a stem (5) engaging inside the windings of the conductor lead (1) and a head (6) securing the electrode (4) in its proper position.

Abstract: A sealed electrical connector comprises an electrically insulated pin housed in a receptacle and has a bared end for contact with a conductor extending partly out of the receptacle. An adjustable mechanical means is provided establishing such contact. A deformable resilient sleeve serves to seal the connection between the pin and receptacle, and access to the mechanical means is only possible through one end and along the sleeve which serves thus to seal the mechanical means.The connector is suitable for use with an implantable cardiac stimulator.