The correlation between the first heart sound and cardiac output as measured by using digital esophageal stethoscope under anaesthesia

Young Duck Shin; Kyoung Hoon Yim; Sang Hi Park; Yong Wook Jeon; Jin Ho Bae; Tae Soo Lee; Myoung Hwan Kim; Young Jin Choi

The correlation between the first heart sound and cardiac output as measured by using digital esophageal stethoscope under anaesthesia

Pak J Med Sci. 2014 Mar;30(2):276-81.

Authors

Young Duck Shin¹, Kyoung Hoon Yim², Sang Hi Park³, Yong Wook Jeon⁴, Jin Ho Bae⁵, Tae Soo Lee⁶, Myoung Hwan Kim⁷, Young Jin Choi⁸

Affiliations

¹ Young Duck Shin, Department of Anesthesiology and Pain Medicine, Chungbuk National University Hospital, Korea.
² Kyoung Hoon Yim, Department of Anesthesiology and Pain Medicine, Chungbuk National University Hospital, Korea.
³ Sang Hi Park, Department of Anesthesiology and Pain Medicine, Chungbuk National University Hospital, Korea.
⁴ Yong Wook Jeon, Department of Anesthesiology and Pain Medicine, Chungbuk National University Hospital, Korea.
⁵ Jin Ho Bae, Dept. of Anesthesiology and Pain Medicine, College of Medicine, Chungbuk National University, Korea.
⁶ Tae Soo Lee, Dept. of Biomedical Engineering, College of Medicine, Chungbuk National University, Korea.
⁷ Myoung Hwan Kim, Laboratory Animal Research Center, Chungbuk National University, Korea.
⁸ Young Jin Choi, Department of Surgery, College of Medicine, Eulji University, Korea.

PMID: 24772126
PMCID: PMC3998993

Abstract

Objective: The use of an esophageal stethoscope is a basic heart sounds monitoring procedure performed in patients under general anesthesia. As the size of the first heart sound can express the left ventricle function, its correlation with cardiac output should be investigated. The aim of this study was to investigate the effects of cardiac output (CO) on the first heart sound (S1) amplitude. Methods : Six male beagles were chosen. The S1 was obtained with the newly developed esophageal stethoscope system. CO was measured using NICOM, a non-invasive CO measuring device. Ephedrine and beta blockers were administered to the subjects to compare changes in figures, and the change from using an inhalation anesthetic was also compared.

Results: The S1 amplitude displayed positive correlation with the change rate of CO (r = 0.935, p < 0.001). The heart rate measured using the esophageal stethoscope and ECG showed considerably close figures through the Bland-Altman plot and showed a high positive correlation (r = 0.988, p < 0,001).

Conclusion: In beagles, the amplitude of S1 had a significant correlation with changes in CO in a variety of situations.

Keywords: Cardiac output; First heart sound; Heart rate; Stethoscope.