Pacemaker with improved inhibit and trigger control

A single chamber pacemaker, comprising sensing means for sensing signals from a chamber of a patient's heart, pace pulse generator means for generating and delivering pace pulses to said patient chamber, trigger mode means for placing said pacemaker in a trigger mode, thereby controlling said generator means to deliver a trigger pulse when said sensing means senses a signal,

• first timing means for timing a normal escape interval,
• second timing means for timing a refractory interval,
• third timing means for timing an inhibit interval,
• fourth timing means for timing a trigger interval which follows said inhibit interval and has a scheduled end coincident with the end of said normal escape interval,
• firth timing means for timing an extended escape interval,
• inhibit means for responding to a signal sensed during said inhibit interval, by controlling said trigger mode means to place said pacemaker into said trigger mode for the remaining duration of said extended interval;
• and
• trigger means for controlling said trigger mode means to place said pacemaker into said trigger mode during said trigger interval.

A pacemaker for pacing at least one chamber of a patient's heart, having pace pulse generator means for generating pace pulses, sense means for sensing signals from said chamber, and control means for normally timing out a normal escape interval following a last event for timing the generation of a pace pulse, said control means further characterized by:

• inhibit range means for timing out an inhibit range following a generated pulse;
• trigger range means for timing out a trigger range following said inhibit range;
• first determining means for determining when a said sensed signal is in said inhibit range and second determining means for determining when a said sensed signal is in said trigger range;
• trigger mode means for placing said pacemaker in a trigger mode and thereby controlling said generator means to deliver a trigger pulse when said sensing means senses a signal,
• first response means for responding to a sensed signal determined to be in said inhibit range by extending said escape interval without delivery of a pace pulse, and controlling said trigger mode means to place said pacemaker in said trigger mode for at least a portion of the remaining time until time out of the extended escape interval;
• and
• second means for controlling said trigger mode means to place said pacemaker in said trigger mode during said trigger range.