Respiratory-dependent pacing: a dual response from a single sensor.
Five patients with respiratory dependent rate responsive pacemakers (Biorate RDP3, Biotec) were studied using ambulatory telemetry to evaluate the sensitivity of this pacing system to nonrespiratory signals. In each case the pacemaker was implanted in the left infraclavicular position with an impedance sensing electrode inserted into the subcutaneous tissues of the anterior chest wall. The pacing rate was 73 +/- 2 beats per minute at rest and rose by 42 +/- 5 beats per minute when the patients were walking with both arms swinging (mean +/- SEM). Three of the five patients had sensing electrodes that extended across the midline. In this subgroup, pacing rate rose by 26 +/- 4 beats per minute when walking with arms held immobile and by 36 +/- 2 beats per minute during sustained voluntary hyperventilation. These same activities did not elicit any appreciable changes in pacing rate in the remaining two patients whose sensing electrodes were confined to the left hemithorax. Recordings taken from all five patients while they were standing upright and regularly swinging one upper limb showed an increase in pacing rate of 15 + 6 beats per minute with movement of the right arm and 46 + 8 with movement of the left. These observations establish that the Biorate RDP3 pacemaker is capable of responding both to changes in respiratory rate and to movement of the upper limbs. The sensitivity to limb movement is greatest when the chest wall impedance sensor does not extend across the midline and is most evident when the arm ipsilateral to the pacemaker is swung.(ABSTRACT TRUNCATED AT 250 WORDS)
Webb
S C
SC
Royal Postgraduate Medical School, London, UK.
Lewis
L M
LM
Morris-Thurgood
J A
JA
Palmer
R G
RG
Sanderson
J E
JE
D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation; D010138:Pacemaker, Artificial; D012119:Respiration