Abstract
Background. We tested the hypothesis that pressure sensitivity of the sternum (PPS) is associated with autonomic nervous system (ANS) function as assessed by tilt table test (TTT). in patients with stable ischemic heart disease. Objectives. (1) To evaluate an association between PPS and systolic blood pressure (SBP) and heart rate (HR) responses to TTT; and (2) to test the hypothesis that a reduction of resting PPS raises the PPS, SBP and HR responses to TTT response and lowers risk factors for ANS dysfunction (ANSD). Methods. Cross-sectional study: In 361 patients with stable ischemic heart disease we measured PPS, SBP, and HR during TTT. Intervention study: We reassessed subjects with persistent stress who concluded a stress intervention trial by a second TTT. Results. Cross-sectional study: Resting PPS and the PPS response to TTT were correlated (r = − 0.37). The PPS response to TTT was correlated with that of SBP (r = 0.44) and HR (r = 0.49), and with the number of risk factors for ANSD (r = − 0.21) (all p < 0.0001). Intervention study: A reduction in resting PPS was associated with an increment in PPS response to TTT (r = − 0.52, p < 0.0001). The greater this increment, the greater was the reduction in ANSD risk factors (r = − 0.23; p = 0.003). Conclusion. The results are consistent with the hypothesis that PPS at rest and in response to TTT reflects ANS function.
Acknowledgements
We are thankful to the staff of the Metabolic Ward for their contribution: Helle-Marina Oxfeldt and Tine Skogen-Lassen. We also thank the staff at the Rehabilitation Unit at Department of Cardiology, Gentofte University Hospital, Copenhagen, Denmark, for providing us with their database on patients with IHD who had completed cardiac rehabilitation. We thank Prof. Niels H. Secher, MD, DMSci, Department of Anaesthesiology, Rigshospitalet, Denmark, for a critical review of the manuscript.
Funding
This work was supported by the Johan Schrøder's Family and Business Foundation. Natasha Bergmann holds a pre-graduate scholarship sponsored by the Lundbeck Foundation.
Declaration of interest: Søren Ballegaard invented the PPS instrument used to measure PPS. He is also a shareholder of the company that owns the patents associated with the PPS instrument. To avoid bias, he was not involved in the patient contact, collection of data, or statistical analysis. No other disclosures were reported. The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.