BI-CHAMBER CARDIAC PACING SYSTEM EMPLOYING UNIPOLAR LEFT HEART CHAMBER LEAD IN COMBINATION WITH BIPOLAR RIGHT HEART CHAMBER LEAD

摘要

Multi-site cardiac pacing systems, including ICD's for pacing right and left heart chambers in inhibited and triggered pacing modes employing combinations of right and left heart chamber pace/sense electrodes for providing left heart chamber pacing and sensing to facilitate placement of the left heart chamber pace/sense electrode at a left heart chamber pace/sense site that is difficult to access. In a bi-ventricular pacing system, an implantable pulse generator optionally having an IPG indifferent electrode is coupled to a small diameter, unipolar, left ventricular (LV) lead and a bipolar right ventricular (RV) lead. The LV lead is advanced through the superior vena cava, the right atrium, the ostium of the coronary sinus (CS), the CS, and into a coronary vein descending from the CS to locate the LV active pace/sense electrode at a desired LV pace/sense site. An LV lead placed on an epicardial surface can substitute. The RV lead in a preferred embodiment is advanced into the RV chamber to locate RV active and indifferent pace/sense electrodes therein. Sensing of RV spontaneous cardiac depolarizations to provide a RV sense event signal and delivery of RV pacing pulses is conducted across the RV active pace/sense electrode and one of the RV or IPG indifferent pace/sense electrodes. Sensing of LV spontaneous cardiac depolarizations to provide a LV sense event signal is conducted across the LV active pace/sense electrode and one of the RV active or indifferent pace/sense electrodes or the IPG indifferent pace/sense electrodes. Delivery of LV pacing pulses is conducted across the LV active pace /sense electrode and the RV indifferent pace/sense electrode. A similar arrangement is disclosed for left atrial (LA) and right atrial (RA) pacing and sensing.