Synchronized atrial and ventricular pacer and timing circuitry therefor

Claim 2

An atrial and ventricular pacer comprising ventricular electrode means, atrial electrode means, means for supplying a ventricular stimulating pulse to said ventricular electrode means at the end of a first timing period, means for supplying an atrial stimulating pulse to said atrial electrode means at the end of a second timing period, first means for detecting a beating action of said patient''s heart and responsive thereto for re-starting said first and second timing periods, means for disabling said detecting means, and second means responsive at least during the operation of said disabling means and to the operation of said ventricular pulse supplying means for restarting said first and second timing

Claim 3

An atrial and ventricular pacer in accordance with claim 1 further including voltage supply means connected to and for energizing at least one of said atrial and ventricular pulse supplying means, said pulse supplying means including a charging circuit having a capacitor and means for charging said capacitor from said voltage supply means, means for deriving a reference potential, means for controlling the supply of a pulse to the respective electrode means when the voltage across the capacitor reaches said reference level, and means for varying the reference level in accordance with the potential of said voltage supply means and for charging said capacitor from an initial level to said reference level in a time substantially independent of the potential of said voltage supply means.

Claim 4

An atrial and ventriculAr pacer in accordance with claim 2 wherein said reference level varying means includes means maintaining the ratio of the potential of said voltage supply means to the magnitude of said reference level substantially constant independent of the potential of said voltage supply means.

Claim 5

An atrial and ventricular pacer in accordance with claim 1 further including voltage supply means having two terminals, said detecting means including a first amplifying stage coupled to said ventricular electrode means, a second amplifying stage for amplifying the output signal of said first amplifying stage, means for energizing both of said first and second amplifying stages from said two terminals, and means for deriving a biasing potential for said first amplifying stage from said second amplifying stage.

Claim 6

An atrial and ventricular pacer in accordance with claim 1 including capacitor means, means for charging said capacitor means to an initial value responsive to the operation of said detecting means, means for discharging said capacitor means following the charging thereof, means responsive to an incremental increase in voltage across said capacitor means which exceeds a predetermined value when said capacitor means is charged by said charging means for operating said first re-starting means, and means for controlling said discharging means to discharge said capacitor means at a rate which is independent of said initial value.

Claim 7

An atrial and ventricular pacer in accordance with claim 5 wherein said discharge controlling means includes means for causing a substantially constant discharge current to flow from said capacitor means.

Claim 8

An atrial and ventricular pacer comprising ventricular electrode means, atrial electrode means, means for supplying a ventricular stimulating pulse to said ventricular electrode means at the end of a first timing period, means for supplying an atrial stimulating pulse to said atrial electrode means at the end of a second timing period, first means for detecting a beating action of said patient''s heart and responsive thereto for re-starting said first and second timing periods, means for disabling said detecting means, and second means responsive at least during the operation of said disabling means and to the termination of said first timing period for re-starting said second timing period.

Claim 9

An atrial and ventricular pacer comprising ventricular electrode means, atrial electrode means, means for supplying a ventricular stimulating pulse to said ventricular electrode means at the end of a first timing period, means for supplying an atrial stimulating pulse to said atrial electrode means at the end of a second timing period, first means for detecting a beating action of said patient''s heart and responsive thereto for re-starting said first and second timing periods, means for disabling said detecting means, and second means responsive at least during the operation of said disabling means and to the termination of said first timing period for re-starting said second timing period.

Claim 10

An atrial and ventricular pacer in accordance with claim 7 including capacitor means, means for charging said capacitor means to an initial value responsive to the operation of said detecting means, means for discharging said capacitor means following the charging thereof, means responsive to an incremental increase in voltage across said capacitor means which exceeds a predetermined value when said capacitor means is charged by said charging means for operating said first re-starting means, and means for controlling said discharging means to discharge said capacitor means at a rate which is independent of said initial value.

Claim 11

An atrial and ventricular pacer in accordance with claim 8 wherein said discharge controlling means includes means for causing a substantially constant discharge current to flow from said capacitor means.

Claim 12

A timing circuit for a heart pacer, said pacer including means for detecting a beating of said patient''s heart and means for disabling said detecting means, said circuit comprising voltage supply means, a charging circuit having a capacitor and means for charging said capacitor from said voltage supply means, means for deriving a reference potential, means for determining the end of a predetermined time interval when the voltage across the capacitor reaches said reference level, means for varying the reference level in accordance with the potential of said voltage supply means, said capacitor charging means charging said capacitor from an initial level to said reference level in a time substantially independent of the potential of said voltage supply means during operation of said detecting means, and in a time substanTially dependent on the potential of said voltage supply means during operation of said disabling means.

Claim 13

A timing circuit for a heart pacer, said pacer including means for detecting a beating of said patient''s heart and means for disabling said detecting means, said circuit comprising voltage supply means, a charging circuit having a capacitor and means for charging said capacitor from said voltage supply means, means for deriving a reference potential, means for determining the end of a predetermined time interval when the voltage across the capacitor reaches said reference level, means for varying the reference level in accordance with the potential of said voltage supply means, said capacitor charging means charging said capacitor from an initial level to said reference level in a time substantially independent of the potential of said voltage supply means during operation of said detecting means, and in a time substanTially dependent on the potential of said voltage supply means during operation of said disabling means.

Claim 14

A timing circuit for a heart pacer in accordance with claim 10 wherein said reference level varying means includes means for maintaining the ratio of the potential of said voltage supply means to the magnitude of said reference level substantially constant independent of the potential of said voltage supply means.