A pacing system includes a signal generator and an electromechanical switch. The signal generator is configured to generate a pacing signal. The electromechanical switch has a plurality of outputs that are configured to be coupled to a plurality of electrodes inserted into a heart of a patient, each output configured to deliver the pacing signal to a respective electrode. The electromechanical switch is configured to route the pacing signal to no more than a single selected one of the outputs at any given time, so as to pace the heart using no more than a single selected one of the electrodes.