A method and medical monitoring device for determining the occurrence of a premature ventricular contraction that includes sensing a cardiac signal and determining R-waves in response to the sensed cardiac signal, determining RR intervals between the determined R-waves, determining whether a first interval criteria is satisfied in response to the determined intervals, determining a correlation between the determined R-waves, determining whether a first correlation criteria is satisfied in response to the determined correlation, and determining the premature ventricular contraction is occurring in response to the first interval criteria and the first correlation criteria being satisfied.
