A method includes disposing at least one pair of electrodes in or on a body of a subject, including disposing at least one intrarenal electrode of the pair in a renal artery. Control circuitry is activate to (a) apply electrical pulses between the pair of electrodes, (b) calculate at least one time-varying component of electrode-tissue impedance based on applying the pulses, (c) sense a periodic hemodynamic signal of the subject, (d) calculate a level of correlation between the at least one time-varying component of the electrode-tissue impedance and the periodic hemodynamic signal, and (e) based on the level of correlation, ascertain a level of contact between the at least one intrarenal electrodes and a wall of the renal artery. In response to the level of contact being less than a threshold level of contact, a disposition of the at least one intrarenal electrodes in the renal artery is adjusted.