Methods and apparatus for determining an endocardial implantation site for implanting an electrode, such as a leadless stimulation electrode. An embodiment of one method in accordance with the invention includes delivering sufficient electrical energy for initiation of cardiac activation to a plurality of different test locations at the heart of a patient, and determining hemodynamic responses in reaction to that the stimulus delivered to the different test locations. This method further includes identifying an implantation site for implanting the electrode by selecting at least one of the test locations corresponding to a favorable hemodynamic response.