A cardiac pacing device, comprising: pulse generation circuitry for generating pacing pulses; sensing circuitry for sensing cardiac electrical activity; a controller for detecting cardiac events that define pacing timing intervals and for controlling the delivery of pacing pulses in accordance with a programmed mode; a switch matrix operable by the controller for connecting the pulse generation circuitry and sensing circuitry to selected electrodes (40 1,..., 40 N) in order to form selected sensing and pacing channels; wherein the controller is programmed to: sense cardiac activity through right ventricular and left ventricular sensing channels; schedule delivery of paces through left ventricular pacing channels to at least two left ventricular sites during a cardiac cycle interval that is reset by a right ventricular sense, wherein the left ventricular paces are delivered in time relation to expiration of an escape interval that is reset by a right ventricular sense and wherein the expiration of the escape interval is marked by a right ventricular pseudo-pace acting as a fiducial point; initiate a left ventricular protective period after a left ventricular sense during which one or more left ventricular paces are inhibited; characterised in that the controller is further programmed to determine whether or not all scheduled left ventricular paces are inhibited during a cardiac cycle interval either by a left ventricular protective period or otherwise; and, if all scheduled left ventricular paces are inhibited, deliver a right ventricular safety pace coincident with the right ventricular pseudo-pace. pulse generation circuitry for generating pacing pulses; sensing circuitry for sensing cardiac electrical activity; a controller for detecting cardiac events that define pacing timing intervals and for controlling the delivery of pacing pulses in accordance with a programmed mode; a switch matrix operable by the controller for connecting the pulse generation circuitry and sensing circuitry to selected electrodes (40 1,..., 40 N) in order to form selected sensing and pacing channels; wherein the controller is programmed to: sense cardiac activity through right ventricular and left ventricular sensing channels; schedule delivery of paces through left ventricular pacing channels to at least two left ventricular sites during a cardiac cycle interval that is reset by a right ventricular sense, wherein the left ventricular paces are delivered in time relation to expiration of an escape interval that is reset by a right ventricular sense and wherein the expiration of the escape interval is marked by a right ventricular pseudo-pace acting as a fiducial point; initiate a left ventricular protective period after a left ventricular sense during which one or more left ventricular paces are inhibited; characterised in that the controller is further programmed to determine whether or not all scheduled left ventricular paces are inhibited during a cardiac cycle interval either by a left ventricular protective period or otherwise; and, if all scheduled left ventricular paces are inhibited, deliver a right ventricular safety pace coincident with the right ventricular pseudo-pace. sense cardiac activity through right ventricular and left ventricular sensing channels; schedule delivery of paces through left ventricular pacing channels to at least two left ventricular sites during a cardiac cycle interval that is reset by a right ventricular sense, wherein the left ventricular paces are delivered in time relation to expiration of an escape interval that is reset by a right ventricular sense and wherein the expiration of the escape interval is marked by a right ventricular pseudo-pace acting as a fiducial point; initiate a left ventricular protective period after a left ventricular sense during which one or more left ventricular paces are inhibited; characterised in that the controller is further programmed to determine whether or not all scheduled left ventricular paces are inhibited during a cardiac cycle interval either by a left ventricular protective period or otherwise; and, if all scheduled left ventricular paces are inhibited, deliver a right ventricular safety pace coincident with the right ventricular pseudo-pace.