Dual site pacing system with automatic pulse output adjustment

A dual site cardiac pacing system, providing fore delivery of substantially concurrent pacing pulses to dual sites in a patient's heart, said system having a pacemaker and leads connected to said pacemaker for delivering pacing pulses to said sites and for obtaining cardiac senses from each of said sites, said pacemaker comprising:

• pulse generator means for cyclically generating said concurrent pulses;
• control means for controlling the timing and power output of said concurrent pulses;
• refractory means for timing out a programmable refractory interval following each generation of said concurrent pulses;
• sensing means for sensing when at least one said cardiac sense occurs at one of said sites during a said refractory interval;
• and
• LOC means for indicating loss of capture at at least one of said sites when at least one said cardiac sense is sensed during said refractory interval;
• comprising first lead means for delivery of pacing pulses to the patient's left ventricle and for obtaining left ventricular senses, and a second lead means for delivery of pacing pulses to the patient's right ventricle and for obtaining right ventricular senses;
• wherein said control means comprises response means for responding to an indicated less of capture by increasing the output level of at least one of said concurrent pulses in response thereto;
• wherein said control means has means for increasing the output level of the pulses delivered to both of said dual sites.

A dual site cardiac pacing system, providing for delivery of substantially concurrent pacing pulses to dual sites in a patient's heart, said patiernt's heart being characterized by an Intraventricular Conduction Delay of up to 300 ms, said system having a pacemaker and leads connected to said pacemaker for delivering pacing pulses to said sites and for obtaining cardiac senses from cach of said sites, said pacemaker comprising:

• pulse generator means for cyclically generating said concurrent pulses;
• control means for controlling the timing and power output of said concurrent pulses;
• refractory means for timing out a programmable refractory interval as set to a value greater than said patient TVCD following each generation of said concurrent pulses;
• sensing means for sensing when at least one said cardiac sense occurs at one of said sites during a said refractory interval;
• LOC means for indicating loss of capture at at least one of said sites when at least one said cardiac sense is sensed during said refractory interval;
• and
• response means for responding to an indicated loss of capture by increasing the output level of at least one of said concurrent pulses in response to an indicated LOC.