Pacemaker sound due to stimulation of thorax muscles by cardiac pacemakers.

Abstract

Abstract. Patients with pacemaker sound due to stimulation of thoracic muscles from cardiac pacemakers are described. The pacemaker sound can be recorded immediately after the pacemaker impulse. The contractions of the intercostal muscles can be recorded on an apex cardiogram. The intensity of the pacemaker sound will in different patients vary from very weak to equal to the loudest heart sound. In some patients pacemaker sound is intermittent, often related to respiration or posture. The incidence in 38 consecutive patients on unipolar endocardial pacing was 26%. Pacemaker sound may indicate current leak or electrode perforation in patients on bipolar endocardial pacing, although the pacemakers seem to function well in the majority of such patients. The disappearance of a previously permanent pacemaker sound may indicate battery exhaustion. The muscular contractions associated with pacemaker sound will be felt as unpleasant by some patients.