Implantable dual site cardiac stimulation device having independent automatic capture capability

A method for pacing a patient's heart using an implantable stimulation device connected to at least two electrodes implanted in a patient's heart wherein a first electrode is positioned to stimulate the right ventricle of the patient's heart and the second electrode is positioned to stimulate the left ventricle of the patient's heart, the method comprising the steps of:

• periodically stimulating the right ventricle of the patient's heart with a first stimulation pulse having a first controlled energy level wherein the first controlled energy level is defined by a set of characteristics including a first amplitude component and a first duration component;
• detecting the presence or absence of an evoked response generated by the right ventricle of the patient's heart in response to the first stimulation pulse during a first detection window;
• increasing the first controlled energy level in response to a loss-of-capture criteria related to the absence of an evoked response from the right ventricle of the patient's heart;
• periodically stimulating the left ventricle of the patient's heart with a second stimulation pulse having a second controlled energy level wherein the second controlled energy level is defined by a set of characteristics including a second amplitude component and a second duration component;
• detecting the presence or absence of an evoked response generated by the left ventricle of the patient's heart in response to the second stimulation pulse during a second detection window;
• increasing the second controlled energy level in response to a loss-of-capture criteria related to the absence of an evoked response from the left ventricle of the patient's heart;
• wherein
• the step of periodically stimulating the left ventricle of the patient's heart additionally comprises the step of setting a time between stimulating the left and right ventricles of the patient's heart to a determined delay period from the stimulation of the right ventricle of the patient's heart by the first stimulation pulse;
• and
• periodically measuring the present output voltage of a battery which powers the implantable stimulation device;
• and wherein
• the steps of increasing the first and second controlled energy levels are dependent upon the first and second amplitude components and the present battery output voltage.

A method for pacing a patient's heart using an implantable stimulation device connected to at least two electrodes implanted in a patient's heart wherein a first electrode is positioned in the right ventricular apex to stimulate the right ventricle of the patient's heart and the second electrode is positioned in the coronary sinus to stimulate the left ventricle of the patient's heart, the method comprising the steps of:

• periodically stimulating the right ventricle of the patient's heart with a first stimulation pulse having a first controlled energy level wherein the first controlled energy level is defined by a set of characteristics including a first amplitude component and a first duration component;
• detecting the presence or absence of an evoked response generated by the right ventricle of the patient's heart in response to the first stimulation pulse during a first detection window;
• increasing the first controlled energy level in response to a loss-of-capture criteria related to the absence of an evoked response from the right ventricle of the patient's heart;
• periodically stimulating the left ventricle of the patient's heart with a second stimulation pulse having a second controlled energy level wherein the second controlled energy level is defined by a set of characteristics including a second amplitude component and a second duration component;
• detecting the presence or absence of an evoked response generated by the left ventricle of the patient's heart in response to the second stimulation pulse during a second detection window;
• increasing the second controlled energy level in response to a loss-of-capture criteria related to the absence of an evoked response from the left ventricle of the patient's heart;
• wherein
• the step of periodically stimulating the left ventricle of the patient's heart additionally comprises the step of setting a time between stimulating the left and right ventricle of the patient's heart to a determined delay period from the stimulation of the right ventricle of the patient's heart by the first stimulation pulse;
• and
• periodically measuring the present output voltage of a battery which powers the implantable stimulation device;
• and wherein
• the steps of increasing the first and second controlled energy levels are dependent upon the first and second amplitude components and the present battery output voltage.

An implantable cardiac stimulation device configured for stimulating a patient's heart through at least two electrodes wherein a first electrode is positioned to stimulate a chamber in the right side of the patient's heart and the second electrode is positioned to stimulate a corresponding chamber in the left side of the patient's heart, the stimulation device comprising:

• a first pulse generator configured for electrical coupling to the first electrode and configured to generate first stimulation pulses at a first controlled energy level to thereby stimulate the right side of the patient's heart, wherein the first controlled energy level is defined by a set of characteristics including an amplitude component and a duration component;
• a first detection circuit configured for electrical coupling to the first electrode and configured to receive cardiac signals for determining the presence or absence of an evoked response to each of the first stimulation pulses;
• a second pulse generator configured for electrical coupling to the second electrode and configured to generate second stimulation pulses at a second controlled energy level to thereby stimulate the left side of the patient's heart, wherein the second controlled energy level is defined by a set of characteristics including an amplitude component and a duration component;
• a second detection circuit configured for electrical coupling to the second electrode and configured to receive cardiac signals for determining the presence or absence of an evoked response to each of the second stimulation pulses;
• a controller coupled to the first and second pulse generators and the first and second detection circuits for adaptively determining the first controlled energy level in response to the signals detected by the first detection circuit and for adaptively determining the second controlled energy level in response to signals detected by the second detection circuit;
• a battery for providing power to the first and second pulse generators that generate the first and second stimulation pulses;
• and
• a voltage detector for detecting the present voltage level of the battery;
• and wherein
• the controller modifies the amplitude components of the first and second controlled energy levels dependent upon the present battery voltage level and the present first and second amplitude components.

An implantable cardiac stimulation device configured for stimulating the right and left sides of a patient's heart, the stimulation device comprising:

• means for generating first stimulation pulses at a first controlled energy level to thereby stimulate the right side of the patient's heart, wherein the first controlled energy level is defined by a set of characteristics including an amplitude component and a duration component;
• first detection means for determining the presence or absence of an evoked response to each of the first stimulation pulses;
• means for generating second stimulation pulses at a second controlled energy level to thereby stimulate the left side of the patient's heart, wherein the second controlled energy level is defined by a set of characteristics including an amplitude component and a duration component;
• second detection means for determining the presence or absence of an evoked response to each of the second stimulation pulses;
• and
• means for adaptively determining the first controlled energy level in response to the first detection means and for adaptively determining the second controlled energy level in response to the second detection means;
• a battery to provide power to the implantable cardiac stimulation device;
• and
• a voltage detector to detect the present voltage level of the battery;
• and wherein
• the controller modifies the amplitude components of the first and second controlled energy levels dependent upon the present battery voltage level and the present first and second amplitude components.