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Correlation of the Heart Rate‐Minute Ventilation Relationship with Clinical Data: Relevance to Rate‐Adaptive Pacing
Author(s) -
SOUCIE LUC P.,
CAREY CLARE,
WOODEND A. KIRSTEN,
TANG ANTHONY S.L.
Publication year - 1997
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 - 10.1111/j.1540-8159.1997.tb03596.x
Subject(s) - medicine , anaerobic exercise , breakpoint , cardiology , ventilation (architecture) , treadmill , respiratory minute volume , heart rate , correlation coefficient , zoology , respiratory system , physical therapy , statistics , mathematics , physics , blood pressure , biology , thermodynamics , biochemistry , chromosomal translocation , chemistry , gene
The heart rate (HR)‐minute ventilation (VE) relationship has been shown to be nonlinear and can be expressed as two distinct straight lines. This study is to assess the correlation of the initial HR‐VE slope to clinical parameters. Maximum treadmill exercise tests were performed in 100 healthy volunteers (age 19–77 years) using a ramp protocol in which work‐rate increases linearly with exercise. Breath‐by‐breath VO 2 , VCO 2 , and VE were measured, and HR and RP were monitored throughout the exercise. The HR‐VE curve demonstrated nonlinearity with a breakpoint determined by a change point analysis. This breakpoint was significantly higher than that of the anaerobic threshold. The VEat the HB‐VE breakpoint was 56.4 ± 19.4 and VE at the VE‐VO 2 and VCO 2 ‐VO 2 breakpoints were 48.0 ± 18.3 (P < 0.0001) arid 40.1 ± 16.5 (P < 0.0001). respectively. TheHR at this HR‐VE breakpoint was 77.7 ± 12.9% of the HR range. The first slope. Si (1.76 ± 0.64) was steeper than the second slope, S2 (0.66 ± 0.39). Although there was a gender difference for S1, the best clinical predictor on a stepwise multiple regression analysis was body surface area (BSA) which explained 47% of the variance. It was concluded that nonlinearity of the HR‐VE curve can be expressed as two straight lines. The breakpoint is beyond the anaerobic threshold and can be estimated to be approximately 75% of the maximal predicted HR. RSA is the only clinical parameter that significantly predicts the initial slope of the HR‐VE curve. This can be of great importance in the programming of rate‐adaptive pacemakers using a VE.