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    <periodOfReport>2019-04-18</periodOfReport>

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    <issuer>
        <issuerCik>0000764579</issuerCik>
        <issuerName>CAS MEDICAL SYSTEMS INC</issuerName>
        <issuerTradingSymbol>CASM</issuerTradingSymbol>
    </issuer>

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            <rptOwnerCik>0001310306</rptOwnerCik>
            <rptOwnerName>PATTON THOMAS M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CAS MEDICAL SYSTEMS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>44 EAST INDUSTRIAL ROAD</rptOwnerStreet2>
            <rptOwnerCity>BRANFORD</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06405</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President and CEO</officerTitle>
        </reportingOwnerRelationship>
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        <derivativeTransaction>
            <securityTitle>
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            <expirationDate>
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            <expirationDate>
                <value>2024-12-18</value>
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                <underlyingSecurityTitle>
                    <value>Common Stock</value>
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        </derivativeTransaction>
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                <transactionShares>
                    <value>60000</value>
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                    <value>0</value>
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                    <value>D</value>
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                <footnoteId id="F8"/>
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            <expirationDate>
                <value>2027-12-21</value>
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                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>60000</value>
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                <directOrIndirectOwnership>
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        </derivativeTransaction>
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    <footnotes>
        <footnote id="F1">Each issued and outstanding share of common stock was, as a result of the consummation of the merger contemplated by the Agreement and Merger by and among CAS Medical Systems, Inc., Edwards Lifesciences Holding, Inc. and Crown Merger Sub, Inc., dated as of February 11, 2019 (the &quot;Merger Agreement&quot;), canceled in exchange for the right to receive a per share amount equal to $2.45 in cash without interest.</footnote>
        <footnote id="F2">These restricted shares were, as a result of the consummation of the merger contemplated by the Merger Agreement, canceled on April 18, 2019 for no consideration.</footnote>
        <footnote id="F3">This option, which vested in equal monthly installments over a four year period commencing on August 27, 2010, was, as a result of the consummation of the merger contemplated by the Merger Agreement, canceled in exchange for a cash payment equal to the product of the number of shares subject to such option multiplied by the excess of $2.45 over the exercise price per share of such option.</footnote>
        <footnote id="F4">This option, which vested in four equal annual installments commencing on December 8, 2011, was, as a result of the consummation of the merger contemplated by the Merger Agreement, canceled in exchange for a cash payment equal to the product of the number of shares subject to such option multiplied by the excess of $2.45 over the exercise price per share of such option.</footnote>
        <footnote id="F5">This option, which vested in four equal annual installments commencing on December 17, 2012, was, as a result of the consummation of the merger contemplated by the Merger Agreement, canceled in exchange for a cash payment equal to the product of the number of shares subject to such option multiplied by the excess of $2.45 over the exercise price per share of such option.</footnote>
        <footnote id="F6">This option, which vested in four equal annual installments commencing on December 16, 2014, was, as a result of the consummation of the merger contemplated by the Merger Agreement, canceled in exchange for a cash payment equal to the product of the number of shares subject to such option multiplied by the excess of $2.45 over the exercise price per share of such option.</footnote>
        <footnote id="F7">This option, which vested in four equal annual installments commencing on December 18, 2015, was, as a result of the consummation of the merger contemplated by the Merger Agreement, canceled in exchange for a cash payment equal to the product of the number of shares subject to such option multiplied by the excess of $2.45 over the exercise price per share of such option.</footnote>
        <footnote id="F8">This option, which vested in four equal annual installments commencing on December 21, 2018, was, as a result of the consummation of the merger contemplated by the Merger Agreement, canceled in exchange for a cash payment equal to the product of the number of shares subject to such option multiplied by the excess of $2.45 over the exercise price per share of such option.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/Thomas M. Patton</signatureName>
        <signatureDate>2019-04-22</signatureDate>
    </ownerSignature>
</ownershipDocument>
