Energy saving cardiac pacemaker

The method of controlling a battery operated cardiac pacemaker implant to produce low energy pacing stimulus pulses at an implanted heart stimulus electrode to conserve battery power, comprising in combination the steps of:

• performing threshold measurements at at least two different stimulus pulse energy levels at the implanted electrode of a particular patient and organizing said stimulus pulses into effective and ineffective energy levels for producing heartbeats,
• determining from the threshold measurements an individual energy threshold characteristic for the particular pacemaker system and patient under test by calculating from said different energy level measurements a substantially most energy efficient stimulus pulse in the implanted pacemaker effective to stimulate the heart,
• adjusting the energy efficient stimulus pulse to the technical capability of the particular pacemaker for operating that pacemaker with a modified optimum energy stimulus pulse exceeding the minimum energy threshold by a predetermined safety margin,
• producing in the pacemaker said modified stimulus pulse, thereby operating the pacemaker at reduced battery energy drain,
• periodically monitoring said threshold characteristic in a patient and dynamically producing said modified pacing pulses to follow changes in the monitored threshold characteristic, and
• following the changes by varying the width of the pacing pulses in a range above chronaxie.

The method of controlling a battery operated cardiac pacemaker implant to produce low energy pacing stimulus pulses at an implanted heart stimulus electrode to conserve battery power, comprising in combination the steps of:

• performing threshold measurements at at least two different stimulus pulse energy levels at the implanted electrode of a particular patient and organizing said stimulus pulses into effective and ineffective energy levels for producing heartbeats,
• determining from the threshold measurements an individual energy threshold characteristic for the particular pacemaker system and patient under test by calculating from said different energy level measurements a substantially most energy efficient stimulus pulse in the implanted pacemaker effective to stimulate the heart,
• determining the threshold characteristic by establishing a minimum energy pulse width that produces a heartbeat with stimulus pulses of two different amplitudes defining a hyperbolic curve representative of the threshold characteristic,
• adjusting the energy efficient stimulus pulse to the technical capability of the particular pacemaker for operating that pacemaker with a modified optimum energy stimulus pulse exceeding the minimum energy threshold by a predetermined safety margin, and
• producing in the pacemaker said modified stimulus pulse, thereby operating the pacemaker at reduced battery energy drain.

A battery operated cardiac pacemaker system for producing pacing pulses at an implanted stimulation electrode at an energy level attaining extended pacemaker battery life, comprising in combination,

• monitoring means for determining a stimulation threshold characteristic by analyzing effective and ineffective stimulation pulses for a particular implanted pacemaker and implanted stimulation electrode,
• logic means for determining the operating conditions of the particular implanted pacemaker for producing stimulation pulses of variable energy content,
• calculating means for establishing a substantially most energy efficient stimulation pulse characteristic for the particular implanted pacemaker and electrode at a pulse energy level exceeding the minimum effective pulse energy level for stimulation by a predetermined safety level, and
• pacing pulse energy control means for automatically responding to produce the established energy efficient stimulation pulses as pacemaker pacing pulses.

A battery operated cardiac pacemaker system for producing pacing pulses at an implanted stimulation electrode at an energy level attaining extended pacemaker battery life, comprising in combination,

• monitoring means for determining a stimulation threshold characteristic by analyzing effective and ineffective stimulation pulses for a particular implanted pacemaker and implanted stimulation electrode,
• logic means for determining the operating conditions of the particular implanted pacemaker for producing stimulation pulses of variable energy content,
• calculating means for establishing an optimum stimulation pulse energy for the particular implanted pacemaker and electrode at a pulse energy level exceeding the minimum effective pulse energy level by a predetermined safety level,
• pacing pulse energy control means for automatically responding to the optimum stimulation pulse energy for producing pacemaker pacing pulses, and
• means for adjusting the pacing pulse energy by varying the width of the pulses in a range exceeding chronaxie.

A battery operated cardiac pacemaker system for producing pacing pulses at an implanted stimulation electrode at an energy level attaining extended pacemaker battery life, comprising in combination,

• monitoring means for determining a stimulation threshold characteristic by analyzing effective and ineffective stimulation pulses for a particular implanted pacemaker and implanted stimulation electrode,
• logic means for determining the operating conditions of the particular implanted pacemaker for producing stimulation pulses of variable energy content,
• calculating means for establishing an optimum stimulation pulse energy for the particular implanted pacemaker and electrode at a pulse energy level exceeding the minimum effective pulse energy level by a predetermined safety level,
• pacing pulse energy control means for automatically responding to the optimum stimulation pulse energy for producing pacemaker pacing pulses, and
• means responsive to two pulses of varying width to determine points on a threshold characteristic curve identifying an algorithm for controlling the pacing pulse energy.

A control system for an energy efficient battery operated pacemaker implanted in a particular patient, comprising in combination,

• programming means external to said implanted pacemaker,
• bidirectional communication means between the programming means and the pacemaker,
• analyzing means to discriminate between pacing pulses ineffective and effective to stimulate the heart,
• logic means to determine automatically in response to the analyzing means an optimum energy efficient setting of pacing pulse width and amplitude for the implanted pacemaker-electrode system in said particular patient, and
• adjusting means operable by said programming means to adjust in the implanted pacemaker the pacing pulse width and amplitude to said optimum setting to achieve long life battery operation.