A method for event detection in a user-wearable device includes receiving, from a first sensor implemented in the user-wearable device, photoplethysmogram (PPG) signals； processing, at a processor, the PPG signals to obtain PPG signal samples； detecting, at the processor, beats in the PPG signal samples； dividing the PPG signal samples into PPG signal segments； extracting at least one inter-beat interval (IBI) feature in each PPG signal segment； classifying, at the processor, each PPG signal segment using the extracted IBI feature associated with the PPG signal segment and using a machine learning model； in response to the classifying, generating, at the processor, an event prediction result for the PPG signal segment based on the extracted IBI feature； and displaying the event prediction result at the user-wearable device. In another embodiment, the method further includes extracting morphology based features.
