Apparatuses and methods are provided for automatically determining which type of resuscitation treatment is most appropriate for a patient. Methods are provided that include the following. One or more time domain signal measurements are transformed into frequency domain data representative of a frequency content of the one or more time domain signal measurements. The frequency domain data is processed to identify peaks. For each of the peaks, for each of multiple points in time, multiple parameters of the peak are determined. Based on the multiple parameters of the peaks for each of the multiple points in time, a trajectory is determined. The determined trajectory is analyzed in determining a recommended type of resuscitation treatment. An output indication is provided of the recommended type of resuscitation treatment.