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世界の電子聴診器のカルディオニクス社が 画面付き、且つ、聴診音解析する新しい電子聴診器をご提案します (薬事未認可に付き注意) |
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Theory of the P wave detection The algorithm first
finds the the possible positive and
negative wave peaks based on zero transition searching, then validates them
with comparing to reference P waves. The P wave detection
needs high amplitude resolution. This value is better, than 0.6 uV / bit in the
Cardiospy system. With this resolution
and the effective filter system which uses wavelet transformation, the Cardiospy
system is able to detect P waves less than 50 uV of amplitude. Validation of the P wave detector The validation is
carried out on 10 pcs 12 channel and 10 pcs 3 channel ECG reference records.
The reference records include the P wave
annotation. 12 of the 20 records
are taken from the MitBih database, 8 records are taken from the Labtech
database (30000 – 30007). 12 ch records s0014lre, s0292lre,
s0302lre, s0331lre, s0364lre, s0422_re, s0431_re, s0437_re, s0549_re, s0550_re 3 ch records mgh001, mgh007,
30000, 30001, 30002, 30003, 30004, 30005, 30006, 30007 Validation result: Sensitivity: 95.42% |
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Clinical update Central blood pressure: current evidence and clinical importance Carmel M. McEniery1*, John R. Cockcroft2, Mary J. Roman3, Stanley S. Franklin4, and Ian B.Wilkinson1 1Clinical Pharmacology Unit,
University of Cambridge, Addenbrooke’s Hospital, Box 110, Cambridge CB22QQ, UK;
2Department of Cardiology,Wales Heart Research Institute, Cardiff CF14 4XN, UK; 3Division of Cardiology,Weill Cornell Medical College, New York, NY
10021, USA; and 4University of California, UCI School of Medicine, Irvine, CA
92697-4101, USA Received 29 April 2013;
revised 27 November 2013; accepted 17 December 2013; online
publish-ahead-of-print 23 January 2014 and central pressure. Therefore, basing treatment decisions on
central, rather than brachial pressure, is likely to have important
implications for the future diagnosis and management of hypertension. Such a
paradigm shift will, however, require further, direct evidence that selectively targeting central pressure, brings added benefit, over and above
that already provided by brachial artery pressure. Keywords Central pressure †
Blood pressure †
Anti-hypertensive treatment †
Cardiovascular risk Introduction The brachial cuff sphygmomanometer was introduced into medical practice well over 100 years ago, enabling the routine,
non-invasive, measurement of arterial blood pressure. Life insurance companies were among the first to capitalize on the information provided by cuff sphygmomanometry, by observing that blood pressure in largely asymptomatic individuals relates to future cardiovascular risk—observations that are nowsupported by a wealth of
epidemiological data.1 The most recent Global Burden of Disease report2 identified hypertension as the leading cause of death and
disability worldwide. Moreover, data from over 50 years of randomized
controlled trials clearly demonstrate that lowering brachial pressure, in hypertensive individuals, substantially reduces cardiovascular events.1,3 For these reasons, measurement of brachial blood pressure has become embedded in routine clinical assessment throughout the developed world, and is one of the most widely accepted ‘surrogate measures’ for regulatory bodies. The major driving force for the continued use of brachial blood pressure has been its ease of measurement, and the wide variety of devices available for clinical use. However, we have known for
over half a century that brachial pressure is a poor surrogate for
aortic pressure, which is invariably lower than corresponding brachial values. Recent evidence suggests that central pressure is also
more strongly related to future cardiovascular events4 – 7 than brachial pressure, and responds differently to certain drugs.8,9 Appreciating this provides an ideal framework for understanding the much
publicized inferiority of atenolol and some other beta-blockers,10 compared with other drug classes, in the management of essential hypertension. Although central pressure can now be assessed
noninvasively with the same ease as brachial pressure, clinicians are unlikely to discard the brachial cuff sphygmomanometer without robust evidence that cardiovascular risk stratification, and
monitoring response to therapy, are better when based on central rather than peripheral pressure. Central pressure assessment and accuracy will also have to be standardized, as it has been for brachial
pressure assessment with oscillometric devices. This review will discuss
our current understanding about central pressure and the evidence required to bring blood pressure measurement, and cardiovascular risk assessment into the modern era. Physiological concepts Arterial pressure varies continuously over the cardiac cycle, but
in clinical practice only systolic and diastolic pressures are
routinely reported. These are invariably measured in the brachial artery using cuff sphygmomanometry—a practice that has changed little over the last century. However, the shape of the pressure waveform * Corresponding author. Tel: +44 1223 336806, Fax: +44 1223 216893, Email: cmm41@cam.ac.uk Published on behalf of the European Society of Cardiology. All
rights reserved. &The Author 2014. For permissions please email:
journals.permissions@oup.com European Heart Journal (2014) 35, 1719–1725 doi:10.1093/eurheartj/eht565 Pressure measured with a cuff and sphygmomanometer in the brachial
artery is accepted as an important predictor of future cardiovascular
risk.However, systolic pressure varies throughout the arterial tree, such that
aortic (central) systolic pressure is actually lower than corresponding brachial values, although this difference is
highly variable between individuals. Emerging evidence now suggests that
central pressure is better related to future
cardiovascular events than is brachial pressure. Moreover, anti-hypertensive
drugs can exert differential effects on brachial and
central pressure. Therefore, basing treatment decisions on central, rather than
brachial pressure, is likely to have important implications for the future diagnosis and management of hypertension. Such a
paradigm shift will, however, require further, direct evidence that selectively targeting central pressure, brings added benefit, over and above
that already provided by brachial artery pressure.As discussed earlier, a full
synthesis of the available evidence concerning central pressure and the risk of future cardiovascular events is now required. However, it will also be necessary
to determine the clinical relevance of differences
between brachial and central pressure for the individual patient, especially given the relatively high
correlation between the
two. Emerging data support the prognostic superiority
of both 24-h ambulatory blood pressure monitoring (ABPM)79 – 81 andhomemonitoring81 in comparison with office measurements. Interestingly, a recent study82 demonstrated that 24-h ambulatory cuff pressures were comparable with
office central pressure measurements in the prediction of risk, although the significance of this study awaits confirmation.83 As yet, there are no data
comparing the
predictive value ofhomemonitoring vs. central pressure in the prediction of risk. Ultimately, it will be necessary to evaluate
the prognostic value of 24-h
ambulatory central pressure.With the recent development of ambulatory central pressure systems,84,85 this is now possible and it may be reasonable to hypothesize that 24-h
central, rather than
brachial ABPM would be superior in terms of risk prediction. |
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