A cardiac rhythm management system comprises a medical electrical lead, a pressure sensing element, and an implantable pulse generator. The lead is sized to be advanced through the right atrium and coronary sinus into a coronary vein adjacent to the left ventricle. The lead includes an opening intermediate its proximal and distal ends, and a lumen extending longitudinally within the body in communication with the opening. The pressure sensing element is movably disposed in lead lumen and is dimensioned to extend through the opening in the lead, and includes a flexible, elongated conductive member having a distal end, and a pressure transducer coupled to the distal end of the conductive member. The pulse generator is configured to receive cardiac rhythm signals from the electrode and fluid pressure signals from the pressure transducer.