What failure results in competition between the pacemaker and the intrinsic rhythm?

The scenario described pertains to the dynamics of cardiac pacemakers and their interactions with the heart's intrinsic rhythm. When a pacemaker fails to sense the heart's intrinsic electrical activity, it does not detect when the heart is attempting to generate its own impulses. Consequently, this can lead to competition between the pacemaker's pacing signals and the heart's intrinsic rhythms.

In this case, if the pacemaker is working but is unable to sense the intrinsic heartbeat, it continues to send pacing impulses at its set rate. If the intrinsic rhythm also remains active, this results in the pacemaker and the heart's intrinsic rhythm competing for control over the heart's contractions. This competition can lead to a variety of detrimental effects, including irregular heart rhythms and inefficient heart function.

An effective sensing function of the pacemaker is critical to ensuring that it operates in harmony with the heart's own rhythm, thus preventing the described competition.