Dual channel cardiac pacer isolation circuit

Claim 1

A system for preventing cross-stimulation between the atrium and ventricle during cardiac pacing using a dual chamber cardiac pacer having a battery power supply, a pacing lead connected to the atrium and a pacing lead connected to the ventricle, which comprises: a first output capacitor connected in series with said atrium lead; a second output capacitor connected in series with said ventricle lead; pulse generating means operatively connected to said first output capacitor for providing a stimulus pulse through said first output capacitor to the atrium and operatively connected to said second output capacitor for providing a stimulus pulse through said second output capacitor to the ventricle; a first switch connected between the battery power supply and said first output capacitor to prevent said first output capacitor from being charged until said first switch is operated to provide a current flow line to said first output capacitor; a second switch connected between the battery power supply and said second output capacitor to prevent said second output capacitor from being charged until said second switch is operated to provide a current flow line to said second output capacitor; and pacer logic means for controlling the operation of said pulse generating means and said first and second switches so that said first switch is operable to provide a current flow line to the first output capacitor only when a stimulus pulse is issued to the atrium and said second switch is operable to provide a current flow line to the second output capacitor only when a stimulus pulse is issued to the ventricle.

Claim 2

A system for preventing cross-stimulation between the atrium and ventricle during cardiac pacing using a dual chamber cardiac pacer having a battery power supply, a pacing lead connected to the atrium and a pacing lead connected to the ventricle, which comprises: a first output capacitor connected in series with said atrium lead; a second output capacitor connected in series with said ventricle lead; pulse generating means operatively connected to said first output capacitor for providing a stimulus pulse through said first output capacitor to the atrium and operatively connected to said second output capacitor for providing a stimulus pulse through said second output capacitor to the ventricle; a first switch connected between the battery power supply and said first output capacitor to prevent said first output capacitor from being charged until said first switch is operated to provide a current flow line to said first output capacitor; a second switch connected between the battery power supply and said second output capacitor to prevent said second output capacitor from being charged until said second switch is operated to provide a current flow line to said second output capacitor; and pacer logic means for controlling the operation of said pulse generating means and said first and second switches so that said first switch is operable to provide a current flow line to the first output capacitor only when a stimulus pulse is issued to the atrium and said second switch is operable to provide a current flow line to the second output capacitor only when a stimulus pulse is issued to the ventricle.

Claim 6

A system for preventing cross-stimulation between the atrium and ventricle during cardiac pacing using a dual chamber cardiac pacer having a battery power supply, a pacing lead connected to the atrium and a pacing lead connected to the ventricle, which comprises: a first output capacitor connected in series with said atrium lead; a second output capacitor connected in series with said ventricle lead; pulse generating means operatively connected to said first output capacitor for providing a stimulus pulse through said first output capacitor to the atrium and operatively connected to said second output capacitor for providing a stimulus pulse through said second output capacitor to the ventricle; a first switch connected between the battery power supply and said first output capacitor to prevent said first output capacitor from being charged until said first switch is operated to provide a current flow line to said first output capacitor; a second switch connected between the battery power supply and said second output capacitor to prevent said second output capacitor from being charged until said second switch is operated to provide a current flow line to said second output capacitor; pacer logic means for controlling the operation of said pulse generating means and said first and second switches so that said first switch is operable to provide a current flow line to the first output capacitor only when a stimulus pulse is issued to the atrium and said second switch is operable to provide a current flow line to the second output capacitor only when a stimulus pulse is issued to the ventricle; said pulse generating means including a first transistor operatively connected to said pacer logic means through an atrial amplitude adjustment circuit for providing an atrial stimulus pulse, and a second transistor operatively connected to said pacer logic means through a ventricle amplitude adjustment circuit for providing a ventricular stimulus pulse; a first charge dump switch connected to said first output capacitor and a second charge dump switch connected to said second output capacitor; said first switch comprising a normally open switch that is closed by said pacer logic means only during the issuance of the atrial stimulus pulse and said second switch is a normally open switch that is closed by said pacer logic means only during the issuance of the ventricular stimulus pulse.

Claim 7

A system for preventing cross-stimulation between the atrium and ventricle during cardiac pacing using a dual chamber cardiac pacer having a battery power supply, a pacing lead connected to the atrium and a pacing lead connected to the ventricle, which comprises: a first output capacitor connected in series with said atrium lead; a second output capacitor connected in series with said ventricle lead; pulse generating means operatively connected to said first output capacitor for providing a stimulus pulse through said first output capacitor to the atrium and operatively connected to said second output capacitor for providing a stimulus pulse through said second output capacitor to the ventricle; a first switch connected between the battery power supply and said first output capacitor to prevent said first output capacitor from being charged until said first switch is operated to provide a current flow line to said first output capacitor; a second switch connected between the battery power supply and said second output capacitor to prevent said second output capacitor from being charged until said second switch is operated to provide a current flow line to said second output capacitor; pacer logic means for controlling the operation of said pulse generating means and said first and second switches so that said first switch is operable to provide a current flow line to the first output capacitor only when a stimulus pulse is issued to the atrium and said second switch is operable to provide a current flow line to the second output capacitor only when a stimulus pulse is issued to the ventricle; said pulse generating means including a first transistor operatively connected to said pacer logic means through an atrial amplitude adjustment circuit for providing an atrial stimulus pulse, and a second transistor operatively connected to said pacer logic means through a ventricle amplitude adjustment circuit for providing a ventricular stimulus pulse; a first charge dump switch connected to said first output capacitor and a second charge dump switch connected to said second output capacitor; said first switch comprising a normally open switch that is closed by said pacer logic means only during the issuance of the atrial stimulus pulse and said second switch is a normally open switch that is closed by said pacer logic means only during the issuance of the ventricular stimulus pulse.

Claim 9

A system for preventing cross-stimulation between the atrium and ventricle during cardiac pacing using a dual chamber cardiac pacer having a battery power supply, a pacing lead connected to the atrium and a pacing lead connected to the ventricle, which comprises: a first output capacitor connected in series with said atrium lead; a second output capacitor connected in series with said ventricle lead; pulse generating means operatively connected to said first output capacitor for providing a stimulus pulse through said first output capacitor to the atrium and operatively connected to said second output capacitor for providing a stimulus pulse through said second output capacitor to the ventricle; means for isolating said first output capacitor from being charged and for isolating said atrium lead until an atrial stimulus pulse is issued; and means for isolating said second output capacitor from being charged and for isolating said ventricle lead until a ventricle stimulus pulse is issued.

Claim 10

A system for preventing cross-stimulation between the atrium and ventricle during cardiac pacing using a dual chamber cardiac pacer having a battery power supply, a pacing lead connected to the atrium and a pacing lead connected to the ventricle, which comprises: a first output capacitor connected in series with said atrium lead; a second output capacitor connected in series with said ventricle lead; pulse generating means operatively connected to said first output capacitor for providing a stimulus pulse through said first output capacitor to the atrium and operatively connected to said second output capacitor for providing a stimulus pulse through said second output capacitor to the ventricle; means for isolating said first output capacitor from being charged and for isolating said atrium lead until an atrial stimulus pulse is issued; and means for isolating said second output capacitor from being charged and for isolating said ventricle lead until a ventricle stimulus pulse is issued.