An apparatus for determining information indicative of cardiac malfunctions includes a processing device (602) configured to detect whether the time-trend of a signal indicative of cardiovascular motion manifests an indicative phenomenon where the amplitude of a first heartbeat is greater than the amplitude of a second heartbeat and the temporary heartbeat rate is greater prior to the first heartbeat than prior to the second heartbeat. The processing device is further configured to produce an indicator of cardiac malfunction, e.g. an indicator of atrial fibrillation, in response to a situation in which the indicative phenomenon is detected to be present.
