Abstract: Transcutaneous electrical nerve stimulation is applied to the patient, as though electrocardiograph monitoring is not being practiced. The EKG signals are preprocessed through a selective sample and hold module, which performs amplification, comparison with selective frequency and amplitude standards (as by differentiation) and temporary holding of EKG signals at such time as the transcutaneous nerve stimulating pulses are occurring, as sensed against the frequency and amplitude criteria. In the absence of transcutaneous stimulation signals, EKG signals are coupled directly through for conventional EKG processing.

Abstract: In a transcutaneous nerve stimulating apparatus, the stimulating pulse wave form is shaped and manipulated to accommodate specific physiological parameters, and to allow multiple non-interfering electrode administrations. The stimulating pulse wave form, of desired pulse rate, pulse duration, and pulse amplitude, optionally includes successive pulses of alternating plurality, which may all be coupled to a single electrode, alternately coupled to plural electrodes, or the like. Pulse decay is controlled, as is pulse rise time. Voltage regulation is provided to the pulse generation apparatus.

Abstract: A plurality of programming bits are placed into a parallel in-serially out register. When the programmer is activated, a monostable resets a counter, and energizes an oscillator which clocks the counter. Three subintervals from the counter are utilized for pulse width modulation of the programming signals. Once for each bit, the output is energized and begins transmitting pulses at the lowest subinterval rate. Depending upon the logic state of each bit, the transmission pulse is terminated either at the second or the third subinterval time.

Abstract: A first oscillator dictates the pulse duration and frequency of stimulating signals; the oscillator output wave form is coupled to an output amplifier stage, and thence to the patient. A scanning oscillator provides a substantially linear ramp voltage, which in turn controls pulse duration, pulse frequency, and pulse intensity modulators. In turn, these modulators appropriately establish conditions within the first oscillator and the output stage whereby the output parameters are scanned through respective predetermined ranges, thereby periodically achieving optimum stimulating conditions.

Abstract: A counter functions in response to an oscillator to control generation of stimulating pulses in the demand mode, via an adjustable rate decoder. The rate decoder may be predetermined under the control of a dual input, a first of which is a magnetic enabling switch, and the second of which is a pulse width modulated magnetic transmission. Once the enabling switch is actuated, plural successive reprogramming bits are coupled to the pacer. Integral logic allows these bits actually to accomplish the programming alteration if and only if the predetermined number of bits occur during a predetermined interval. The reprogramming is further synchronized with the generation of stimulating pulses.

Abstract: A free running oscillator clocks a counter, which produces stimulation control signals at a predetermined counter. An output stage includes transistors, energized by the counter, to issue stimulating pulses having a voltage equal to that across a capacitor in parallel with the output stage. The output capacitor is charged, between output pulses, by successive charge sharing cycles with at least one other capacitor, which is enabled by a stored program word, at a rate determined by the oscillator output cycles.

Abstract: An implanted receiver-decoder stores program bits corresponding to rate alteration and to input amplifier sensitivity. The former bits operate a rate decoder which in turn is responsive to predetermined outputs of a fixed rate oscillator-counter. The input amplifier is connected to the intermediate tap of a potential divider, one arm of which senses signals at the heart, and the other of which is either set at a fixed potential, or is allowed to float, under control of the input amplifier sensitivity programming signal.

Abstract: A demand pacer has a local memory element, programmable from a remote source, which detects whether or not the hysteresis rate adjustment is to be employed. When hysteresis is disabled, the pacer operates in the normal demand mode, at a rate optionally selected by the same memory. In the hysteresis mode, a flip-flop controls gating means, ultimately operable at conventional or hysteresis rates, ultimately for controlling the output amplifier. An input amplifier senses natural heart beat signals, and enables a gating means, which has been conditioned for hysteresis mode operation, to reset the flip-flop and in turn the output controlling gates.