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, in use: sense cardiac activity through a right ventricular sensing channel; operate in a normal pacing mode if a cardiac cycle interval expires without a right ventricular sense having occurred; and operate in a biventricular-triggered pacing mode if a right ventricular sense occurs before the cardiac cycle interval expires; J wherein, in the normal pacing mode, the controller schedules delivery of paces through left ventricular pacing channels to at least two left ventricular sites upon expiry of the cardiac cycle interval; and further wherein, in the biventricular-triggered pacing mode, triggered by said right ventricular sense, the controller schedules delivery of a pace to the right ventricle through a right ventricular pacing channel and delivery of a single pace to the left ventricle at a selected left ventricular site. 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, in use: sense cardiac activity through a right ventricular sensing channel; operate in a normal pacing mode if a cardiac cycle interval expires without a right ventricular sense having occurred; and operate in a biventricular-triggered pacing mode if a right ventricular sense occurs before the cardiac cycle interval expires; J wherein, in the normal pacing mode, the controller schedules delivery of paces through left ventricular pacing channels to at least two left ventricular sites upon expiry of the cardiac cycle interval; and further wherein, in the biventricular-triggered pacing mode, triggered by said right ventricular sense, the controller schedules delivery of a pace to the right ventricle through a right ventricular pacing channel and delivery of a single pace to the left ventricle at a selected left ventricular site. sense cardiac activity through a right ventricular sensing channel; operate in a normal pacing mode if a cardiac cycle interval expires without a right ventricular sense having occurred; and operate in a biventricular-triggered pacing mode if a right ventricular sense occurs before the cardiac cycle interval expires; J wherein, in the normal pacing mode, the controller schedules delivery of paces through left ventricular pacing channels to at least two left ventricular sites upon expiry of the cardiac cycle interval; and further wherein, in the biventricular-triggered pacing mode, triggered by said right ventricular sense, the controller schedules delivery of a pace to the right ventricle through a right ventricular pacing channel and delivery of a single pace to the left ventricle at a selected left ventricular site.