An implantable medical device configured to provide for an intra-cardiac pacing, the implantable medical device comprising: an electrode arrangement (11, 12) configured to sense a cardiac sense signal; and a processing circuitry operatively connected to the electrode arrangement (11, 12), wherein the processing circuitry is configured to start a first timer based on a ventricular sense event (Vs) identified using the cardiac sense signal or based on a ventricular pace event (Vp); to open an atrial detection window (T sense) based on a first timer count output by the first timer; to start a second timer in case an atrial sense event (As) is identified using the cardiac sense signal after opening the atrial detection window (T sense); to identify a first timeout based on a comparison of a second timer count output by the second timer and a first pacing delay indicative of a delay after which a ventricular pace signal should be triggered following a prior atrial sense event (As); characterised in that the processing circuitry is further configured to identify a second timeout based on a comparison of the first timer count output by the first timer and a second pacing delay indicative of a delay after which a ventricular pace signal should be triggered following a prior ventricular sense event (Vs) or ventricular pace event (Vp); to identify a third timeout based on a comparison of the first timer count output by the first timer and a basic rate interval indicative of a longest allowable interval without a ventricular sense event (Vs) or ventricular pace event (Vp); and to trigger a ventricular pace signal based on an identification of at least one of the first timeout, the second timeout and the third timeout. an electrode arrangement (11, 12) configured to sense a cardiac sense signal; and a processing circuitry operatively connected to the electrode arrangement (11, 12), wherein the processing circuitry is configured to start a first timer based on a ventricular sense event (Vs) identified using the cardiac sense signal or based on a ventricular pace event (Vp); to open an atrial detection window (T sense) based on a first timer count output by the first timer; to start a second timer in case an atrial sense event (As) is identified using the cardiac sense signal after opening the atrial detection window (T sense); to identify a first timeout based on a comparison of a second timer count output by the second timer and a first pacing delay indicative of a delay after which a ventricular pace signal should be triggered following a prior atrial sense event (As); characterised in that the processing circuitry is further configured to identify a second timeout based on a comparison of the first timer count output by the first timer and a second pacing delay indicative of a delay after which a ventricular pace signal should be triggered following a prior ventricular sense event (Vs) or ventricular pace event (Vp); to identify a third timeout based on a comparison of the first timer count output by the first timer and a basic rate interval indicative of a longest allowable interval without a ventricular sense event (Vs) or ventricular pace event (Vp); and to trigger a ventricular pace signal based on an identification of at least one of the first timeout, the second timeout and the third timeout. to start a first timer based on a ventricular sense event (Vs) identified using the cardiac sense signal or based on a ventricular pace event (Vp); to open an atrial detection window (T sense) based on a first timer count output by the first timer; to start a second timer in case an atrial sense event (As) is identified using the cardiac sense signal after opening the atrial detection window (T sense); to identify a first timeout based on a comparison of a second timer count output by the second timer and a first pacing delay indicative of a delay after which a ventricular pace signal should be triggered following a prior atrial sense event (As); characterised in that the processing circuitry is further configured to identify a second timeout based on a comparison of the first timer count output by the first timer and a second pacing delay indicative of a delay after which a ventricular pace signal should be triggered following a prior ventricular sense event (Vs) or ventricular pace event (Vp); to identify a third timeout based on a comparison of the first timer count output by the first timer and a basic rate interval indicative of a longest allowable interval without a ventricular sense event (Vs) or ventricular pace event (Vp); and to trigger a ventricular pace signal based on an identification of at least one of the first timeout, the second timeout and the third timeout.