PosterPDF Available

High level infrasound exposure reduces the contractility of human cardiac tissues in in-vitro model

Abstract

Human exposure to infrasound is increasing due to man-made factors, like industrial installations, wind farms and transportation. A growing concern among the public regarding the safety of this exposure can be noticed. The aim of this work is to evaluate whether exposure to infrasound interferes directly with human cardiac function and hence attributes to any kind of pathological process. Experiment design: first the samples were stimulated for a period of 30 minutes until they reached a steady state. Then the CF and CD are measured (CF 1 & CD 1) over a period of 10 minutes. After that, infrasound was applied for a period of 60 minutes during continuous electrical stimulation. A second sample from every patient served as a control. At the end, the measurement was repeated (CF 2 & CD 2) again over a further period of 10 minutes. The Ratios between the values (CF 2 / CF 1 & CD 2 / CD 1) were calculated for each trial. Human myocardial tissues, obtained from patients undergoing cardiac surgery, were prepared in small muscle samples and then stimulated electrically with a frequency of 75 bpm for a period of almost 120 minutes under sustained perfusion with an oxygenated physiological solution. Two samples were obtained from each patient: one was subjected to infrasound at 16 Hz and the other served as a control. The exhibited isometric contraction force (CF) and contraction duration (CD) were measured before and after the treatment. The changes in these values (CF % and CD % , corresponding to the ratios between the values after the exposure and before) were evaluated and analyzed as dependent variables in a multiple linear regression model, considering the ratios in the corresponding control samples and infrasound levels of exposure as explanatory variables. Three infrasound levels of exposure were used in this study: 100, 110 and 120 dBz. No weighting system was used. Methods Results The measured CF % in the samples treated with infrasound were proportional to the measured CF % in the corresponding control samples (p= 0.001) and corresponded negatively with the infrasound level of exposure measured in dBz (r²=0.56; p= 0.044). The decrease in CF % measured almost 7.5% for every 10 dBz above the 100 dBz limit, resulting in almost 15% decrease in contraction force at 120 dBz. The CD % remained unchanged after the treatment with infrasound. Conclusion Exposure to high levels of infrasound (more than 100 dBz) interferes harmfully with the cardiac contraction function, even as soon as after one hour of exposure. There are plenty of other works that support this conclusion. The effect of infrasound obviously goes beyond the direct mechanical effect in increasing the cross-bridge breakage and involve a wide range of process, like calcium metabolism und mitochondrial integrity. These results should be considered when looking at environmental regulations. We recommend introducing a maximal tolerated infrasound level for long-term exposure as low as 80 dBz. Using multiple linear regression, we found the measured CF % in the samples treated with infrasound to be proportional to the measured CF % in the corresponding control samples (p= 0.001) and negatively corresponded with the infrasound level of exposure measured in dBz (r²=0.56; p= 0.044). The decrease in CF % measured almost 7.5% for every 10 dBz above the 100 dBz limit, resulting in almost 15% decrease in contraction force at 120 dBz.
Background
High level infrasound exposure reduces the contractility of human cardiac
tissues in in-vitro model
Chaban R, Ghazy A, Brendel L, Buschmann K, Vahl C-F
Dept. of Cardiothoracic and Vascular Surgery
136. Kongress der Deutschen Gesellschaft für Chirurgie
Abstract-ID: 410, Poster-Nr.: DGCH - 13
Human exposure to infrasound is increasing due to man-made factors, like
industrial installations, wind farms and transportation. A growing concern
among the public regarding the safety of this exposure can be noticed. The
aim of this work is to evaluate whether exposure to infrasound interferes
directly with human cardiac function and hence attributes to any kind of
pathological process.
Dr. med. R. Chaban
Department of Cardiothoracic and Vascular Surgery
University Hospital of Johannes Gutenberg University Mainz
rayan.chaban@unimedizin-mainz.de
Experiment design: first the samples were stimulated for a period of 30 minutes
until they reached a steady state. Then the CF and CD are measured (CF1& CD1)
over a period of 10 minutes. After that, infrasound was applied for a period of 60
minutes during continuous electrical stimulation. A second sample from every
patient served as a control. At the end, the measurement was repeated (CF2&
CD2) again over a further period of 10 minutes. The Ratios between the values
(CF2/ CF1& CD2/ CD1) were calculated for each trial.
Human myocardial tissues, obtained from patients undergoing cardiac
surgery, were prepared in small muscle samples and then stimulated
electrically with a frequency of 75 bpm for a period of almost 120 minutes
under sustained perfusion with an oxygenated physiological solution. Two
samples were obtained from each patient: one was subjected to infrasound
at 16 Hz and the other served as a control. The exhibited isometric
contraction force (CF) and contraction duration (CD) were measured
before and after the treatment. The changes in these values (CF%and
CD%, corresponding to the ratios between the values after the exposure
and before) were evaluated and analyzed as dependent variables in a
multiple linear regression model, considering the ratios in the
corresponding control samples and infrasound levels of exposure as
explanatory variables.
Three infrasound levels of exposure were used in this study: 100, 110 and
120 dBz. No weighting system was used.
Methods
Results
The measured CF%in the samples treated with infrasound were
proportional to the measured CF%in the corresponding control samples
(p= 0.001) and corresponded negatively with the infrasound level of
exposure measured in dBz (r²=0.56;p= 0.044). The decrease in CF%
measured almost 7.5% for every 10 dBz above the 100 dBz limit, resulting
in almost 15% decrease in contraction force at 120 dBz.
The CD%remained unchanged after the treatment with infrasound.
Conclusion
Exposure to high levels of infrasound (more than 100 dBz) interferes
harmfully with the cardiac contraction function, even as soon as after one
hour of exposure. There are plenty of other works that support this
conclusion. The effect of infrasound obviously goes beyond the direct
mechanical effect in increasing the cross-bridge breakage and involve a
wide range of process, like calcium metabolism und mitochondrial integrity.
These results should be considered when looking at environmental
regulations. We recommend introducing a maximal tolerated infrasound
level for long-term exposure as low as 80 dBz.
Using multiple linear regression, we found the measured CF%in the samples
treated with infrasound to be proportional to the measured CF%in the
corresponding control samples (p= 0.001) and negatively corresponded with the
infrasound level of exposure measured in dBz (r²=0.56; p= 0.044). The decrease
in CF%measured almost 7.5% for every 10 dBz above the 100 dBz limit, resulting
in almost 15% decrease in contraction force at 120 dBz.
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