A dual chamber cardiac pacemaker apparatus, comprising: first means for electrically coupling the apparatus to an atrial chamber； second means for electrically coupling the apparatus to a ventricular chamber； signal generator means for generating a sequential pair of pacing pulses； and distribution means for distributing a first pacing pulse from the pair at a first amplitude to the first means, and for distributing a second pacing pulse from the pair at a second amplitude to the second means after a delay period.
