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Respiratory sinus arrhythmia in man: relation to right ventricular output
Acta Physiologica Scandinavica. Supplementum
|January 1, 1976
Summary
Investigating respiratory effects on heart function, this study found that negative inspiratory pressure (NIP) and intermittent positive pressure ventilation (IPPV) significantly impact heart rate (HR) and right ventricular stroke volume (SV RV). These findings suggest a link between respiratory mechanics and cardiac regulation.
Area of Science:
- Cardiovascular Physiology
- Respiratory Physiology
Background:
- The interplay between respiratory mechanics and cardiac function is complex.
- Understanding how external respiratory pressures influence heart rate and stroke volume is crucial for clinical applications.
Purpose of the Study:
- To investigate the beat-by-beat effects of negative inspiratory pressure (NIP) and intermittent positive pressure ventilation (IPPV) on heart rate (HR), right ventricular stroke volume (SV RV), and pulmonary arterial flow (PAF).
Main Methods:
- Conscious, healthy subjects underwent controlled breathing maneuvers with varying tidal volumes (VT) and respiratory rates.
- Intrathoracic pressure was manipulated using NIP and IPPV.
- Hemodynamic parameters including HR, SV RV, and PAF were measured continuously.
Main Results:
- Control conditions showed normal inspiratory increases in HR (respiratory sinus arrhythmia) and SV RV.
- NIP augmented inspiratory increases in SV RV and pulmonary arterial flow oscillations.
- IPPV led to decreased SV RV and HR during inspiration.
Conclusions:
- Both NIP and IPPV exert significant effects on right ventricular stroke volume and right heart blood flow.
- The parallel changes in HR and SV RV suggest a potential causal relationship mediated by cardiac reflexes.