A cardiac rhythm management system includes a sensing circuit to sense a cardiac signal and a sensing processor to detect cardiac depolarizations (beats) by utilizing certain morphological context of the sensed cardiac signal. The sensing processor samples the sensed cardiac signal, computes curvatures from the sampled cardiac signal to generate a cardiac curvature signal corresponding to the cardiac signal, derives cardiac signal features reflecting morphologically significant points along the cardiac signal from the cardiac curvature signal, and detects cardiac depolarizations based on an analysis of the cardiac signals features.