Atrial tachycardia-detecting heart stimulator comparing a plurality of P-P intervals with a threshold

A heart stimulator comprising:

• atrial detector means adapted for interacting with a patient for detecting atrial events in said patient, said atrial detector means having a blanking period during which any detected atrial events are ignored;
• ventricular stimulation means for emitting ventricular stimulation pulses and adapted for delivering said ventricular stimulation pulses to said patient;
• interval setting means for generating a variable PV interval between an atrial event detected by said atrial detector means and emission of a next one of said ventricular stimulation pulses by said ventricular stimulation means for causing said ventricular stimulation means to emit said next one of said ventricular pulses at an end of Said variable PV interval;
• time measurement means for measuring a PP interval between two consecutive atrial events detected by said atrial detector means;
• and
• means for detecting whether atrial tachycardia is present in said patient including means for causing said interval setting means to generate a set PV interval such that a sum of said set PV interval and said blanking period is less than or equal to an adjustable threshold value, and for placing said time measurement means in a mode for emitting a signal indicating the presence of atrial tachycardia if each of a defined plurality of consecutive PP intervals measured by said time measurement means is less than said adjustable threshold value.