The activitrax rate responsive pacemaker system

• Published in: The American journal of cardiology Vol. 61; no. 1; pp. 107 - 112
• Main Authors: Dulk, Karel Den, Bouwels, Leon, Lindemans, Fred, Rankin, Ian, Brugada, Pedro, Wellens, Hein J.J.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 1988; Elsevier
• Subjects: Adult; Aged; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Arrhythmias, Cardiac - therapy; Biological and medical sciences; Electrocardiography; Emergency and intensive cardiocirculatory care. Cardiogenic shock. Coronary intensive care; Female; Heart Rate; Humans; Intensive care medicine; Male; Medical sciences; Middle Aged; Pacemaker, Artificial; Physical Exertion; Heart; Human; Atrium; Intensive cardiocirculatory care; Right ventricle; Cardiovascular disease; Standby stimulation; Instrumental stimulation; Electrocardiography; Exercise tolerance test; Frequency; Ambulatory; Hemodynamics; Monitoring
• ISSN: 0002-9149; 1879-1913
• DOI: 10.1016/0002-9149(88)91314-8

Bipolar Medtronic Activitrax rate responsive pacemakers were implanted in 31 patients for ventricular (28) or atrial (3) pacing. Mean follow-up was 16 months (range 10 to 26). Twenty pacemakers were implanted after catheter ablation of the His bundle, 7 for sick sinus syndrome, 1 for atrioventricular block and 3 for sick sinus syndrome with atrioventricular block. A rate response value was selected that gave a pacing rate of about 100 pulses/min during waking. Of the 31 patients, all had 24-hour ambulatory electrocardiographic monitoring with diary, 11 walked a 20-minute circuit, including a flight of stairs, and 20 had a treadmill exercise test. In 9 patients the pacing rate could be compared with the underlying sinus rate during exercise and was seen to match it very closely. In 12 patients the pacing rate during car driving was found to be similar to the sinus rate of 5 volunteers under similar conditions (mean minimum and maximum rate was 80 and 99 pulses/min, respectively). No pacing-induced arrhythmias were seen during ambulatory electrocardlographic monitoring. At high pacing rates slightly irregular pacing intervals were sometimes observed, which was due to polarization sensing. Sporadically, 1 pacing interval shortened to the upper rate value, because of a known and now resolved timing anomaly. Neither anomaly was of clinical consequence and the first could be resolved by reprogramming. It te concluded that this rate responsive pacemaker is safe, easy to program and increases heart rate appropriately during exercise; the bipolar version can be used safely for atrial pacing; and rate response and activity threshold values that give a pacing rate of about 100 pulses/min during casual walking provide appropriate changes in heart rate during normal daily life.