[Carotid sinus massage in pacemaker patients with heart rates about the pacemaker frequency]

The delivery of pacing impulses is inhibited in patients with VVI(R) pacemakers whose intrinsic heart rate is above pacing rate. Efficacy of the pacing impulse can be evaluated on surface ECG by application of a magnet on the pacemaker which temporarily induces asynchronous pacing. Carotid sinus massage can alternatively lower intrinsic heart rate below pacing rate. The study investigates in how many patients carotid sinus massage lowers heart rate below pacing rate during follow-up, and whether the efficacy is reduced in the presence of a pacing rate programmed below the nominal setting. Patients with pacing rates 61-72 ppm (group I) were compared to patients whose pacemakers were programmed to 51-60 ppm (group II) and 40-50 ppm (group III). A right- and leftsided carotid sinus massage was performed in 119 consecutive patients. Right-sided carotid sinus massage was positive in 64 and left-sided in 53 patients. The second, left-sided carotid sinus massage induced pacing in additional 11 patients. In general, carotid sinus massage lowered heart rate below pacing rate in 75 (70%) patients. Induction of pacing was significantly lower (p < 0.02) in group III (n = 31/57; 54%) compared to group I (n = 17/20; 85%). No differences were detected between group II (n = 27/42; 64%) and group I.

Carotid sinus massage is a useful method for induction of pacing in patients whose intrinsic heart rate is above pacing rate.