A Comparative Study of Activity and Dual Sensor: Activity and Minute Ventilation Pacing Responses to Ascending and Descending Stairs

Abstract

Previous studies with activity-based rate adaptive pacemakers have shown a somewhat paradoxical response when comparing ascending stairs to descending stairs. The objective of this investigation was to measure dual-sensor rate response provided by activity and minute ventilation (MV) compared with activity alone, and with a control group, during ascending and descending stairs. For dual sensor mode, measured mean peak pacing rate with 72 (92) steps per minute was 111 +/- 13 beats/min (124 +/- 14 beats/min) ascending stairs and 81 +/- 7 beats/min (97 +/- 13 beats/min) for descending. For activity mode alone, mean peak pacing rate was 90 +/- 12 beats/min (108 +/- 19 beats/min) ascending stairs and 97 +/- 12 beats/min (123 +/- 17 beats/min) descending. The mean peak control group heart rate ascending stairs for a step rate of 72 (92) steps/min were 116 +/- 11 beats/min (127 +/- 14 beats/min) ascending stairs and for descending 89 +/- 12 beats/min (95 +/- 11 beats/min). While for dual sensor controlled pacing there was a significant difference for ascending and descending stairs at both step rates, there was no difference between going upstairs and downstairs for activity mode alone. Rates with dual sensor did not significantly differ from respective rates of the control group. The mean correlation coefficient between MV and paced rate was 0.85. Pacing heart rates delivered by the dual sensor mode were appropriate for ascending and descending stairs. In contrast to activity mode alone, the peak heart rates for dual sensor mode are higher during ascending than during descending stairs.

A BioMEMS Review: MEMS Technology for Physiologically Integrated Devices

“…Combinations of sensors have also been investigated. The combination of an activity sensor with a minute ventilation sensor, for example, has been shown to provide more physiological response to exercise [151].…”

Stair Negotiation in Older People: A Review

“…However, Roberts and Palmer 68 found very few arrhythmias during the climbing of 20 stairs by subjects in a small sedentary group (mean age 68 years) that had been chosen to exclude subjects with symptomatic cardiac arrhythmias, ischemic heart disease, or use of antihypertensive medications. Different modes of triggering in cardiac pacemakers have been found to generate different responses to climbing and descending stairs, with dual sensor mode devices generating high heart rates during ascent 69 …”

Analysis of the O-wave in acute right ventricular apex impedance measurements with a standard pacing lead in animals

“…When needed, the pulse generator emits stimulation pulses to the cardiac tissue through the intravenous pacemaker lead by electrodes situated inside the heart, causing it to contract. Modem pacemakers do not only maintain a basic heart rate by fixed-rate stimulation, they are also designed to mimic the physiological behaviour during physical load in different ways (KARLOF, 1974;DAS and CARLBLOM, 1990;LAU, 1992;ALT et al, 1998;SCHALDACH et al, 1992;NAPHOLZ et al, 1987;. So far, the overall ambition has been to avoid sensors that would complicate the otherwise robust and standardised leads.…”

“…A pacemaker system does not require any specialised leads or sensors to measure intracardiac impedance, it is processed by pulse generator electronics using the available pacemaker lead electrodes and pulse generator capsule. Because of this important advantage and the need for physiological stimulation control, all major pacemaker manufacturers have pacemaker models using impedance in some way (ALT et al, 1998;SCHALDACH et al, 1992, NAPHOLZ et al, 1987.…”

“…et al (1970) relationship between this signal and ECG and cardiac time intervals is mainly studied using the first derivative of the transthoracic impedance cardiogram dZ/dt (KUBICEK et al, 1974;KARNE6IS and KUBICEK, 1970 (SHOEMAKER et al 1994;KARNEGIS et al, 1981;HUBBARD et al, 1986;WOLTJER et al, 1997;ALT et al, 1998;PICKET and BUELL, 1993;MUZI et al, 1985).…”