External cardiac pacemaker and method of pacing threshold determination to an external pacemaker

The invention relates to an external pacemaker to the bi-atrial stimulation with a control or regulating unit for delivering at least one stimulation pulse, the stimulation of the left or right atrium is optionally deactivated. The invention further relates to a method for threshold determination with such external cardiac pacemaker, wherein the atrial pace pulse output disabled alternately for the left and right atrium and the stimulus threshold is determined individually for the left and right atrium.