1. A cardiac rhythm management system comprising: a cardiac lead adapted to be delivered to a target location within a coronary vein having an inner wall, the cardiac lead including: an elongated lead body including a distal end; a first electrode coupled to the lead body; a second electrode coupled to the lead body; and at least one conductor extending within the lead body operatively coupled to at least one of the first electrode and the second electrode; a strain sensing element coupled to the distal end of the lead body and disposed apart from the first electrode and the second electrode, the strain sensing element configured to radially expand against and frictionally engage the inner wall of the coronary vein, and further configured to generate an output signal indicative of changes in a localized inner dimension of the coronary vein during a cardiac cycle; and a pulse generator including a processor operatively coupled to the strain sensing element, the processor configured to receive the output signal from the strain sensing element and to estimate a measure of hemodynamic performance therefrom, wherein the localized inner dimension is an inner diameter of a portion of the coronary vein, and wherein the processor is configured to calculate a difference ΔD max−min between a maximum inner diameter and a minimum inner diameter of the portion of the coronary vein during the cardiac cycle and to estimate the measure of hemodynamic performance based on Δ Dmax−min .