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Impact of Adaptive Rate Pacing Controlled by a Right Ventricular Impedance Sensor on Cardiac Output in Response to Exercise
Author(s) -
COOK LINNEA,
HAMILTON DAWN,
BUSSE EDWARD,
TSANG JOHN,
GARBE GEORGE,
WOJCIK WADYSLAW,
HAENNEL ROBERT
Publication year - 2003
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1046/j.1460-9592.2003.00025.x
Subject(s) - medicine , impedance cardiography , cardiac output , heart rate , stroke volume , cardiology , hemodynamics , heart failure , ejection fraction , blood pressure
COOK, L., et al. : Impact of Adaptive Rate Pacing Controlled by a Right Ventricular Impedance Sensor on Cardiac Output in Response to Exercise.This study examined the effects of adaptive rate pacing controlled by closed‐loop right ventricular impedance sensing on exercise hemodynamics. Twelve patients in whom Biotronik INOS 2+ pacemakers had been implanted 4–6 weeks earlier participated in the study. All patients completed two graded, symptom‐limited exercise tests. The pacemaker was programmed to DDDR with an upper rate limit of 75–85% of the age‐predicted maximum heart rate and a lower rate limit of 45–60 ppm. Heart rate was recorded continuously. An average of 5 beats during the last 10 seconds of each exercise stage was used in the analysis. Oxygen uptake (VO 2 ) was measured using open circuit spirometry. The VO 2 values from the final 15 seconds of each exercise stage were used for analysis. Stroke volume and cardiac output were measured during the last minute of each stage using impedance cardiography. The test‐retest reliability of heart rate and cardiac output responses to graded exercise was assessed using repeated measures analysis of variance, for which the reliability coefficients were r = 0.993 and r = 0.954, respectively (P < 0.01). There were significant correlations (P < 0.01) between VO 2 and heart rate and between VO 2 and cardiac output, with correlation coefficients of r = 0.907 and r = 0.824, respectively. This method of adaptive rate pacing produced reliable, positive hemodynamic responses to graded exercise on a test‐retest basis. (PACE 2003; 26:[Pt. II]:244–247)