Method and apparatus for monitoring left ventricular work or power

A method of pacing a patient's heart, comprising:

• providing a lead system into a coronary vein of a left ventricle of the patient's heart, the lead system comprising:
• an elongated body;
• at least one electrode at a distal end of the lead system;
• and
• at least one thermal sensor at a distal end of the lead system;
• providing a flow sensor in the patient's heart, the flow sensor sensing cardiac output;
• sensing ventricular electrical rhythms at the at least one electrode;
• and
• sensing a coronary vein blood temperature from the at least one thermal sensor and sensing a left ventricular flow rate from the flow sensor to adaptively modify delivery of synchronized electrical signals delivered to the patient's heart.

A method of pacing a patient's heart, comprising:

• providing a lead system into a vein of the patient's heart, the lead system comprising:
• an elongated body;
• an open lumen;
• and
• at least one electrode at distal end of the lead system;
• providing a sensing catheter within the open lumen of the lead system until a distal tip of the sensing catheter extends beyond a distal tip of the lead system, the sensing catheter comprising at least one thermal sensor at a distal end of the sensing catheter;
• measuring ventricular electrical rhythms from the at least one electrode;
• and
• measuring a coronary vein blood temperature from the at least one thermal sensor to adaptively modify delivery of the synchronized electrical signals delivered to the patient's heart.

A body implantable system, comprising:

• a lead system comprising:
• an elongated body suitable for positioning into a coronary vein;
• at least one electrode at a distal end of the elongated body;
• a thermal sensor located proximal to the distal end of the elongated body, the thermal sensor for sensing an average coronary sinus blood temperature at a location distal to the coronary sinus ostium when the at least one electrode is positioned in a coronary vein;
• and
• a programmable circuit coupled to the lead system, the programmable circuit determining a hemodynamic state from the sensed average coronary sinus blood temperature.