Method and apparatus for detection of premature atrial contraction

An implantable cardiac stimulator for identifying a premature atrial contraction, comprising the steps of:

• a cardiac lead having a tip with a plurality of electrodes thereon, electrically separated from each other adapted for placement, in contact with cardiac tissue so that at least two of said electrodes are simultaneously in contact with said cardiac tissue, to obtain respective unipolar signals from said at least two electrodes resulting from a depolarization wave in said cardiac tissue;
• a signal processor supplied with said unipolar signals for analyzing said unipolar signals to identify a propagation direction of said depolarization wave relative to said tip of said cardiac lead and for classifying said depolarization wave as representing a premature atrial contraction dependent on said direction, and for generating an output signal indicating said direction;
• and
• a cardiac therapy administration arrangement connected to said cardiac lead and to said signal processor for generating and administering, via said cardiac lead, stimulation therapy to said cardiac tissue dependent on said output signal from said signal processor.