A cardiac pacing system preventing short-long-short pacing sequences. The system providing pacing pulses where necessary. The system having dynamic event window generation to adapt to changes in heart rate. The event window adaptable to process a number of intervals. The system including provisions for other inputs, such as sensor and morphology detection. The system adaptable for single mode and dual mode applications. The system also applicable to long pause prevention in atrial pacing and ventricular pacing.