Key result
Passive head-up tilt in patients with CAD increased the high frequency power of RT interval variability to 266% ± 83% (P < 0.01), likely reflecting mechanical rather than sympathetic changes.
Why the study?
Does passive head-up tilt alter the spontaneous beat-to-beat variability of the RT interval in patients with coronary artery disease?
Population
19 patients with coronary artery disease (CAD)
Comparison
Passive head-up tilt vs Supine position
Design
Cross-sectional
Authors
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May caution against sympathetic interpretation of tilt-induced RT variability in CAD; leaves open its role in autonomic or risk assessment.
Observational (n=19)
Does passive head-up tilt alter the spontaneous beat-to-beat variability of the RT interval in patients with coronary artery disease?
p-value: p=< 0.01
The increase in high-frequency RT interval variability during tilting is likely a mechanical phenomenon related to respiration and central venous pressure changes rather than sympathetic activity.
Müller et al. (1997) conducted an observational in Coronary artery disease (CAD) (n=19). Passive head-up tilt vs. Supine position was evaluated on High frequency (HF) range of RT interval variability (RTV) (p=< 0.01). Passive head-up tilt in patients with CAD increased the high frequency power of RT interval variability to 266% ± 83% (P < 0.01), likely reflecting mechanical rather than sympathetic changes.
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