Comparison of the normal sinus node with seven types of rate responsive pacemaker during everyday activity.

Abstract

The heart rate response of 59 patients aged 17-79 years implanted with seven different types of rate responsive pacemakers was evaluated during graded exercise treadmill testing and during standardised daily activities. The heart rate response in patients with pacemakers was compared with the chronotropic response in 20 healthy controls of similar age and sex distribution who performed identical protocols. All pacemaker types adequately simulated the control heart rate response during the graded exercise treadmill test except during the early stages of exercise. However, during everyday activities, the response of ventricular rate responsive (VVIR) Most previous studies to assess sensor driven rate responsive pacemakers used treadmill testing or bicycle ergometry.'l'8 We compared heart rate changes in patients with single and dual chamber rate responsive pacemakers with the chronotropic response in a group of healthy controls during various standardised everyday activities and during graded exercise treadmill tests. Patients and methods PATIENTSFifty nine patients aged 17-79 years (mean 57-9, 35 (590o) men) had seven types of rate responsive pacemaker implanted. Ventricular rate responsive pacemakers (VVIR) were implanted in 33 patients. They were the activity sensing Siemens Sensolog I (10), minute ventilation sensing Telectronics Meta (8), activity sensing Medtronic Activitrax (8), and QT sensing Vitatron Tx II (7). None of these patients had the signs or symptoms of the pacemaker syndrome."' Dual chamber rate responsive systems were implanted in 26 patients. Six had Medico Phymos VDD systems, which require a single lead with free floating atrial bipolar sensing and unipolar ventricular sensing and pacing; 10 had DDD systems; and 10 had activity sensing DDDR systems. The table shows the indications for implantation.All patients were followed up at 6 weeks and 3 months after pacemaker implantation and were optimally programmed to the rate response mode according to the manufacturers' instructions.We studied heart rate responses in a group of 20 apparently healthy people aged 23-76 years (mean 55 0, 12 (60%) men) during standardised daily activities and treadmill testing.

Beat‐to‐Beat Heart Rate Adaptation in Pediatric and Late Adolescent Patients with Closed Loop Rate‐Responsive Pacemakers

“…With the evolution of device and the reduction of lead dimension it has been possible to extend the indication for cardiac pacing in infants and children 1,2 . The good outcome of long‐term evaluation of transvenous leads, 3 and the efficacy and reliability of the various sensors developed in the last years 4–10 have contributed to considering dual‐chamber pacemakers (DDD) for the treatment of several pathologies 11–14 . Notwithstanding the encouraging results, some important aspects are still to be defined: most sensors either fail to adapt pacing rates to non‐movement stress (e.g., mental or standing) or show inappropriate response to movements not strictly requiring physiological adaptation (e.g., traveling by car or bus).…”

Clinical Performance of Automatic Closed‐Loop Stimulation Systems

“…CLS responded to emotional circumstances in a similar fashion to the natural heart rates 8,9 , 15,16 . The second execution of the CWT resulted in lower peak CLS rates than the first execution (Fig.…”

Closed Loop Stimulation is Effective in Improving Heart Rate and Blood Pressure Response to Mental Stress: Report of a Single‐Chamber Pacemaker Study in Patients with Chronotropic Incompetent Atrial Fibrillation

“…Many rate‐adaptive systems have been developed in these years to offer HR variability to patients implanted with pacemakers. Each system has sensors that analyze different physiological parameters including: vibrations caused by physical activity, respiratory rate, and volume, right atrial pressure, thoracic impedance, venous blood pH, temperature, oxygen saturation, and the intracardiac evoked QT interval of the paced beat 10 …”

“…Moreover, Sulke et al, comparing seven different types of rate‐responsive pacemaker, found the QT devices were slow to react to burst exercise and tended to underrespond to exercise protocols 10 …”