P-Wave control, R-wave inhibited ventricular stimulation device

Claim 2

A heart stimulating device for stimulating the heart of a patient, said device comprising terminal means for connection to said patient's heart, timing means for at least establishing timing intervals at least as long as a basic interval, pulse generator means for generating a ventricular stimulation impulse on said terminal means at end of each of said timing intervals, first means for detecting the beating action of the atrium of said heart, means responsive to the operation of said first detecting means for generating an A-V interval pulse, said timing means including control means responsive to said A-V interval pulse for at least lengthening said timing interval beyond said basic interval if the otherwise next generated one of said ventricular stimulation impulses would have occurred during the time of occurrence of said A-V interval pulse and for limiting said lengthened interval to be no longer than the sum of said basic interval and the interval of said A-V interval pulse, second means for detecting the beating action of the ventricle of said heart, and means responsive to the operation of said second detecting means for resetting said timing means.

Claim 3

The heart stimulating device of claim 1 wherein said A-V interval pulse is of predetermined length and the end of each said lengthened timing interval is substantially concurrent with the end of a respective said A-V interval pulse.

Claim 4

The heart stimulating device of claim 2 wherein said timing means additionally selectively establishes said timing intervals as shorter than said basic interval, said control means being operative for alternatively shortening said timing interval to less than said basic interval if said detected beating action of the atrium occurs within a predetermined interval ending prior to the end of said basic interval by said length of said A-V interval pulse.

Claim 5

The heart stimulating device of claim 3 wherein the end of each said shortened timing interval is substantially concurrent with the end of a respective said A-V interval pulse.

Claim 6

The heart stimulating device of claim 4 wherein said predetermined interval is at least as long as said length of said A-V interval pulse whereby said shortened timing interval may be at least as short as the difference between said basic interval and the interval of said A-V interval pulse.

Claim 7

The heart stimulating device of claim 5 wherein said predetermined interval is longer than said length of said A-V interval pulse whereby said shortened timing interval may be shorter than the difference between said basic interval and the interval of said A-V interval pulse.

Claim 8

The heart stimulating device of claim 2 wherein said timing means includes means for establishing a threshold voltage, means responsive to said A-V interval pulse for adjusting said threshold voltage, capacitive means, means for charging said capacitive means and means for detecting when voltage on said capacitive means is substantially equal to said threshold voltage, said pulse generator means being repetitively responsive to said detection of equal voltages for generating respective said ventricular stimulation impulses and discharging said capacitive means with each generation, and said timing means resetting means also being operative to discharge said capacitive means responsive to the operation of said second detection means.

Claim 9

The heart stimulating device of claim 7 wherein the increase in said adjusted threshold voltage is substantially constant for the duration of said A-V interval pulse.

Claim 10

The heart stimulating device of claim 7 wherein said A-V interval pulse is a voltage waveform and said means for adjusting said threshold voltage comprises means for extending the voltage of said A-V interval pulse to said threshold voltage establishing means in at least temporarily additive relationship therewith, thereby temporarily increasing said threshold voltage against which said capacitive means voltage is compared.

Claim 11

The heart stimulating device of claim 9 wherein said A-V interval pulse voltage extending means comprises an other capacitive means.

Claim 12

The heart stimulating device of claim 10 wherein the time-constant of said other capacitive means in combination with said threshold voltage establishing means in such that said adjusted threshold voltage declines from a first increased value to a second value intermediate said first value and the normal said threshold voltage by the end of a respective said A-V interval pulse, said adjusted threshold voltage temporarily assuming a third value immediately after the end of a respective said A-V interval pulse, said third value being less than the normal said threshold voltage by the amount of said decline in said adjusted threshold voltage during said A-V interval pulse, said third value of adjusted threshold voltage temporarily decreasing the voltage of said capacitive means at which said ventricular impulses are generated for additionally alternatively enabling said timing interval to be shortened from said basic timing interval.

Claim 13

The heart stimulating device of claim 11 wherein the end of each said shortened timing interval is substantially concurrent with the end of a respective said A-V interval pulse, and said time-constant and accordingly, said second value of adjusted threshold voltage are selected such that said timing intervals may be alternatively shortened or lengthened from said basic interval by as much as the interval of said A-V interval pulse.

Claim 14

The heart stimulated device of claim 12 further including selectively operative means for disabling both said atrium beating detection means and said ventricular beating detection means whereby said ventricular stimulation impulses are repetitively generated by said timing means and pulse generator at a single timing interval corresponding with said basic interval.

Claim 15

A heart stimulating device for stimulating the heart of a patient, said device comprising terminal means for connection to said patient's heart, means for establishing a threshold voltage, capacitive means, means for charging said capacitive means, means for detecting when voltage on said capacitive means is substantially equal to said threshold voltage, pulse generator means responsive to the operations of said detecting means for repetitively generating ventricular stimulation impulses at varying intervals on said terminal means and discharging said capacitive means with each generation, atrial means for sensing atrial beating of said patient's heart, means responsive to operation of said atrial sensing means for adusting said threshold voltage during a first predetermined time interval substantially smaller than the smallest of said varying intervals, means responsive to said adjusted threshold for controlling said pulse generator means to provide said impulse at the end of said first predetermined time interval if said pulse generator means would otherwise have provided said impulse during a second predetermined interval, said second predetermined interval being about twice the length of said first predetermined interval and beginning with the beginning of said first predetermined interval, ventricular means for sensing ventricular beating action of said patient's heart, and means responsive to the operation of said second sensing means for discharging said capacitive means.

Claim 16

A heart stimulating device for stimulating the heart of a patient, said device comprising terminal means for connection to said patient's heart, means for establishing a threshold voltage, capacitive means, means for charging said capacitive means, means for detecting when voltage on said capacitive means is substantially equal to said threshold voltage, pulse generator means responsive to the operations of said detecting means for repetitively generating ventricular stimulation impulses at varying intervals on said terminal means and discharging said capacitive means with each generation, atrial means for sensing atrial beating of said patient's heart, means responsive to operation of said atrial sensing means for adusting said threshold voltage during a first predetermined time interval substantially smaller than the smallest of said varying intervals, means responsive to said adjusted threshold for controlling said pulse generator means to provide said impulse at the end of said first predetermined time interval if said pulse generator means would otherwise have provided said impulse during a second predetermined interval, said second predetermined interval being about twice the length of said first predetermined interval and beginning with the beginning of said first predetermined interval, ventricular means for sensing ventricular beating action of said patient's heart, and means responsive to the operation of said second sensing means for discharging said capacitive means.