Karbing, Dan Stieper

Poulsen, Mathias Krogh

Schmidt, Samuel Emil

Struijk, Johannes Jan

Søgaard, Peter

Sørensen, Kasper

English

Cardio Respiratory Fitness (CRF) is a strong predictor of mortality. Because of this the American Heart Association recommends that ideally all patients should have measured CRF with a maximal effort test on a regular basis. However, this is not practically possible. Seismocardiography (SCG) is a measure of the vibration produced by the beating heart, measured on the sternum. This study investigates the correlation between amplitudes in the SCG and VO2-max from 17 females and 9 males. All amplitudes investigated correlated significantly with VO2-max.Cardio Respiratory Fitness (CRF) is a strong predictor of mortality. Because of this the American Heart Association recommends that ideally all patients should have measured CRF with a maximal effort test on a regular basis. However, this is not practically possible. Seismocardiography (SCG) is a measure of the vibration produced by the beating heart, measured on the sternum. This study investigates the correlation between amplitudes in the SCG and VO2-max from 17 females and 9 males. All amplitudes investigated correlated significantly with VO2-max

    Aalborg UniversitetCorrelation Between Valve Event Amplitudes in the Seismocardiogram and VO2-maxSørensen, Kasper; Poulsen, Mathias Krogh; Karbing, Dan Stieper; Søgaard, Peter; Struijk,Johannes Jan; Schmidt, Samuel EmilCreative Commons LicenseUnspecifiedPublication date:2019Document VersionAccepted author manuscript, peer reviewed versionLink to publication from Aalborg UniversityCitation for published version (APA):Sørensen, K., Poulsen, M. K., Karbing, D. S., Søgaard, P., Struijk, J. J., & Schmidt, S. E. (2019). CorrelationBetween Valve Event Amplitudes in the Seismocardiogram and VO2-max. Abstract from Engineering inMedicine and Biology 2019, Berlin, Germany.General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright ownersand it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.            ? Users may download and print one copy of any publication from the public portal for the purpose of private study or research.            ? You may not further distribute the material or use it for any profit-making activity or commercial gain            ? You may freely distribute the URL identifying the publication in the public portal ?Take down policyIf you believe that this document breaches copyright please contact us at vbn@aub.aau.dk providing details, and we will remove access tothe work immediately and investigate your claim.Downloaded from vbn.aau.dk on: November 24, 2020   Fig. 1:  A normal SCG with notation of the fiducial points. -200 -100 0 100 200 300 400 500 600Time with respect to ECG R-peak [ms]-0.0200.02Amplitude [g]SCGDdGsFsEsCdBd  Abstract—Cardio Respiratory Fitness (CRF) is a strong predictor of mortality. Because of this the American Heart Association recommends that ideally all patients should have measured CRF with a maximal effort test on a regular basis. However, this is not practically possible. Seismocardiography (SCG) is a measure of the vibration produced by the beating heart, measured on the sternum. This study investigates the correlation between amplitudes in the SCG and VO2-max from 17 females and 9 males. All amplitudes investigated correlated significantly with VO2-max. I. INTRODUCTION According to an American Heart Association (AHA) Scientific Statement from 2016, CRF is potentially a stronger risk predictor of mortality than smoking, diabetes and hypertension [1]. CRF can be estimated by maximal oxygen consumption (VO2-max) with a maximal effort cycle ergometer test. This test is not well suited for the elderly or obese patients. In this study we investigated using recordings of vibrations on the chest produced by the beating of the heart, SCG, and its correlation to VO2-max. SCG is a deterministic signal recorded non-invasively on the sternum with an accelerometer [2].	II. METHODS Seventeen females and 9 males were recruited for the study. All subjects signed written informed consent form. Demographic data, SCG and electrocardiography (ECG) was recorded for 5 minutes at rest. VO2-max was measured with a Vyntus CPX during a maximal effort bike ergometer test. The female subjects participated in a follow up recording session, after 8 weeks of structured high intensity training for 2 hours a week. Based on the ECG R-peak, the SCG was divided into individual beats and one mean SCG beat was calculated for each subject. From the mean SCG beats the peak-to-peak amplitudes between the location of the mitral valve closure (Es) and the following valley Fs, Fs to aortic valve opening (Gs), aortic valve closure (Bd) to the following valley Cd and lastly Cd to Dd was measured (see Fig I) [3]. The amplitudes were correlated with the VO2-max using the Pearson’s Correlation. III. RESULTS The mean VO2-max for the females was 28.7 (± 4.5) (mL/kg)/min prior to the 8 weeks of training, compared to   1Aalborg University, Denmark, Health Science and Technology. Contact: ks@hst.aau.dk 2 Aalborg University Hospital, Denmark. Department of Cardiology. 31.2 (± 6.5) (mL/kg)/min after training (p < 0.05). The mean VO2-max for the males was 40.1 (± 8.4) (mL/kg)/min. The correlations between the amplitudes of the valve events and VO2-max are listed in Table I. TABLE I.  PEARSON’S CORRELATION COEFFICIENT AMD P-VALUE BETWEEN VALVE EVENT AMPLITUDES AND VO2-MAX Event n Correlation [r] p-value Es to Fs 48 -0.47 < 0.001 Fs to Gs 48 0.47 < 0.001 Bd to Cd 48 -0.72 < 0.001 Cd to Dd 48 0.81 < 0.001 IV. DISCUSSION & CONCLUSION The amplitude of Cd to Dd could be caused by the heart moving towards its apex when the aortic valve closes [2]. The amplitude of this event could be manipulated by the speed of the pressure drop in the left ventricle. Faster ventricular relaxation has previously been shown in athletes compared to normal subjects. This study shows a correlation between amplitudes measured in the SCG and VO2-max, presenting a novel non-exercise method for estimating CRF. REFERENCES [1] R. Ross et al., “Importance of Assessing Cardiorespiratory Fitness in Clinical Practice: A Case for Fitness as a Clinical Vital Sign: A Scientific Statement from the American Heart Association,” Circulation, vol. 134, no. 24, pp. e653–e699, 2016. [2] P. Mounsey, “Praecordial ballistocardiography,” Br. Heart J., vol. 19, no. 2, pp. 259--271, 1957. [3] K. Sørensen et al., “Difinition of Fiducial Points in the Normal Seismocardiogram,” Sci. Rep., vol. 8, no. 1, p. 15455, 2018. Correlation Between Valve Event Amplitudes in the Seismocardiogram and VO2-max Kasper Sørensen1 (Member IEEE), Mathias Krogh Poulsen1, Dan Stieper Karbing1 (Member IEEE), Peter Søgaard2, Johannes J. Struijk1, and Samuel Emil Schmidt1 (Member IEEE) 

Correlation Between Valve Event Amplitudes in the Seismocardiogram and VO2-max

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Correlation Between Valve Event Amplitudes in the Seismocardiogram and VO2-max

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