초록 ▼

A method and apparatus are disclosed for measuring the ohmic, that is, purely d-c, resistance at the area of contact between cardiac tissue and a pacemaker electrode surgically implanted in the heart of a patient requiring a pacemaker. The contact resistance is measured by apparatus connected across

A method and apparatus are disclosed for measuring the ohmic, that is, purely d-c, resistance at the area of contact between cardiac tissue and a pacemaker electrode surgically implanted in the heart of a patient requiring a pacemaker. The contact resistance is measured by apparatus connected across the electrical circuit formed by the electrode and heart. The apparatus includes circuitry for sampling and holding the instantaneous voltage across the electrical circuit formed by the electrode and heart at the onset of a pulse generated by the pacemaker pulse generator, at which time the effect of a parallel capacitance in the electrical circuit formed by the pulse generator, electrode wire, electrode, heart, and return path through the body to the pulse generator is such that the current initially produced is determined only by the voltage and equivalent output impedance of the pulse generator, the resistance of the electrode wire, and the resistance at the area of contact between cardiac tissue and the electrode. The apparatus further includes analog signal processing circuitry for deriving the contact resistance from the instantaneous voltage based on an equivalent circuit model for the electrical circuit formed by the pacemaker and the heart taking into account the effect of the parallel capacitance at the onset of a pulse. The apparatus also includes a device for displaying the measured contact resistance. The disclosed method and apparatus are also applicable for measuring the ohmic contact resistance of an electrode attached to other body tissue.

대표청구항 ▼

A method for measuring the ohmic contact resistance of an electrode attached to body tissue, the method including the steps of: attaching the electrode to the body tissue; connecting a pulse generator having a given pulse amplitude and a given equivalent output impedance to the electrode, the pulse

A method for measuring the ohmic contact resistance of an electrode attached to body tissue, the method including the steps of: attaching the electrode to the body tissue; connecting a pulse generator having a given pulse amplitude and a given equivalent output impedance to the electrode, the pulse generator, electrode, and body tissue forming an electrical circuit; generating a pulse by means of the pulse generator; determining the instantaneous voltage across the body tissue and electrode at the onset of the pulse; deriving the ohmic contact resistance of the electrode based on the given amplitude, the given equivalent output impedance, and the instantaneous voltage; and displaying the ohmic contact resistance.