SECOND LOAN EXTENSION AND
                             MODIFICATION AGREEMENT


         This  Second  Loan   Extension   and   Modification   Agreement   (this
"Agreement")  is made and  entered  into this 2nd day of October,  1998,  by and
between ZIONS FIRST NATIONAL BANK  ("Lender") and MERIT MEDICAL  SYSTEMS,  INC.,
("Merit Medical  Systems"),  MERIT MEDICAL  INTERNATIONAL,  INC. ("Merit Medical
International"),  MERIT HOLDINGS,  INC.  ("Merit  Holdings"),  and SENTIR,  INC.
("Sentir"). Merit Medical Systems, Merit Medical International,  Merit Holdings,
and Sentir are hereafter collectively referred to as "Borrowers").

                                    Recitals
                                    --------

         A.  Borrowers  have a  revolving  line of credit (the "Line of Credit")
with Lender in the current maximum principal amount of $10,500,000.00, evidenced
and governed by the following  documents,  among others  (collectively the "Loan
Documents"):


                  1.       Loan Agreement dated October 10, 1995 entered into by
                           Merit Medical Systems (the "Loan Agreement");
                  2.       Promissory   Note  dated  October  10,  1995  in  the
                           original  maximum  principal  amount of $8,500,000.00
                           entered into by Merit Medical Systems (the "Note");
                  3.       Trust Deed with Assignment of Rents dated October 10,
                           1995,  executed by Merit Medical Systems, as Trustor,
                           and recorded October 18, 1995 as Entry No. 6192795 in
                           Book  7251  beginning  at Page  0903 of the  official
                           records of the Salt Lake County  Recorder (the "Trust
                           Deed");
                  4.       Security  Agreement  dated October 10, 1995,  entered
                           into by Merit Medical Systems,  whereby Merit Medical
                           Systems  granted  to Lender a security  interest  in,
                           among other things,  all of its inventory,  accounts,
                           general intangibles  (including,  without limitation,
                           certain patents described in the Security Agreement),
                           equipment,  furnishings,  and  fixtures,  all as more
                           particularly described in the Security Agreement (the
                           "Security Agreement");
                  5.       Loan  Extension  and  Modification   Agreement  dated
                           October  10,  1997  entered  into  by  Merit  Medical
                           Systems,  whereby the Line of Credit was  modified as
                           follows:  (a) the maturity date of the Line of Credit
                           was  extended  to October 1,  1998,  (b) the  maximum
                           principal  amount of the Line of Credit was increased
                           to $10,500,000.00,  (c) the interest rate on the Line
                           of Credit was reduced by .25%, (d) the maximum amount
                           of raw materials and finished goods used to calculate
                           the  limitation on advances  under the Line of Credit
                           was increased from  $3,000,000.00  to  $3,500,000.00,
                           (e) the ratio of total  liabilities  to tangible  net
                           worth  was  increased  from  [1.0 to 1.0] to [1.10 to
                           1.0], and (f) the maximum working capital requirement
                           was increased from $7,000,000.00 to $9,000,000.00;
                  6.       Supplemental   Trust  Deed  dated  October  10,  1997
                           executed by Merit Medical  Systems,  as Trustor,  and


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                           recorded  October  21,  1997 as Entry No.  6768327 in
                           Book  7786  beginning  at Page  0554 of the  official
                           records of the Salt Lake County Recorder;
                  7.       Loan  Assumption  Agreement  dated  October  10, 1997
                           entered  into by  Borrowers,  whereby  Merit  Medical
                           International, Merit Holdings, and Sentir assumed the
                           liabilities, duties, and obligations of Merit Medical
                           Systems   under  the  Loan   Documents   and   became
                           additional makers of the Note, and Merit Holdings and
                           Sentir became  additional  debtors under the Security
                           Agreement,   all  without   affecting   the  existing
                           liabilities of Merit Medical Systems  thereunder (the
                           "Assumption Agreement").

         B.  Borrowers  have  requested  that Lender extend the maturity date of
the Line of Credit  until  October 1, 1999 and modify the Line of Credit by: (a)
reducing the interest  rate based on the LIBOR Rate by 1.00% and (b)  increasing
the maximum  amount of raw  materials  and finished  goods used to calculate the
limitation  on  advances  under  the  Line  of  Credit  from   $3,500,000.00  to
$4,000,000.00.  Lender is willing to do so,  subject to the terms and conditions
of this  Agreement,  which  include  not  interrupting  or  otherwise  adversely
affecting the priority of Lender's lien and security interests created under and
evidenced by the Trust Deed and the Security Agreement.

                                    Agreement
                                    ---------

         For good and valuable  consideration,  the receipt and  sufficiency  of
which are hereby acknowledged,  Lender and Borrowers hereby agree and modify the
Line of Credit and Loan Documents as follows:

         1. Except as otherwise expressly provided herein,  terms defined in the
Loan Documents shall have the same defined meanings in this Agreement.

         2. The parties represent and warrant to each other that, in deciding to
enter  into  this  Agreement,  they  each  (a)  made  their  own  due  diligence
investigation  and evaluation;  (b) had all of the information they needed;  (c)
did not rely on any statements, acts, or omissions except as expressly set forth
in this Agreement;  (d) were not acting under any duress,  compulsion,  or undue
influence;  and (e) were (or had the  opportunity  to be) advised by independent
legal counsel.

         3. By this  Agreement,  the Line of Credit and the Loan  Documents  are
modified as follows:

                  A. The  maturity  date of the Line of Credit is extended  from
         October 1, 1998 to October 1, 1999.  All  amounts  owing on the Line of
         Credit shall become immediately due and payable on October 1, 1999.

                  B. The  interest  rate based on the LIBOR Rate (as  defined in
         the Note)  specified in the Note shall be reduced by 1.00%, or in other
         words from 2.85% above the LIBOR Rate to 1.85% above the LIBOR Rate.


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                  C.  The maximum  amount of raw  materials  and finished  goods
                      used to calculate  the  limitation  on advances  under the
                      Line  of  Credit  are  increased  from   $3,500,000.00  to
                      $4,000,000.00.

                  D.  The  following  provision  is  hereby  added  to the  Loan
                      Agreement:

                           Year 2000  Compliance.  "Year 2000 compliant"  means,
                  with regard to any entity, that all material software utilized
                  by such entity is able to fully function  without  causing any
                  error to such entity's  date-sensitive data. "Providers" means
                  the key suppliers,  vendors,  and customers of Borrowers whose
                  business failure would, with reasonable probability, result in
                  a  material  adverse  change  in the  financial  condition  or
                  prospects of Borrowers.

                           Borrower  has or will  soon  have  (i)  undertaken  a
                  detailed  assessment of all areas within its initial  business
                  and operations that could be adversely affected by the failure
                  of Borrowers to be Year 2000  compliant,  (ii)  developed  and
                  implemented a detailed  plan for becoming Year 2000  compliant
                  on a timely basis,  and (iii) made written  inquiry of each of
                  its  Providers as to whether the  Providers  will be Year 2000
                  compliant on a timely basis.  Borrowers  will promptly  advise
                  Lender in writing upon the occurrence of any of the following:
                  (i)  Borrowers  determine  or  Borrowers  are advised by their
                  accountants,  financial advisers, consultants, or any Provider
                  that Borrowers or any Provider will not be Year 2000 compliant
                  on  a  timely   basis  or  (ii)   Borrowers  or  any  Provider
                  experiences data or data processing problems due to failure to
                  be Year 2000 compliant.

         4.  Contemporaneous  with the execution and delivery of this Agreement,
Merit Medical  Systems shall execute and deliver to Lender a Supplemental  Trust
Deed, in a form acceptable to Lender,  whereby the Trust Deed is supplemented to
state the extended  maturity  date and reduced  interest  rate under the Line of
Credit.

         5.  Except as expressly  modified by this  Agreement,  all of the terms
and conditions of the Line of Credit and the Loan Documents shall remain in full
force and effect,  and, as modified by this Agreement,  the Line of Credit shall
continue to be secured as provided in the Loan Documents.

         6.  Representations  and  Warranties.  Borrowers each hereby affirm and
again  make  the   representations   and  warranties  set  forth  in  Article  5
Representations  and  Warranties  of the Loan  Agreement  and Paragraph 5 of the
Assumption Agreement as of the date of this Agreement.

         7.  Authorization.  Borrowers  each  represent  and  warrant  that  the
execution,  delivery,  and  performance  of this  Agreement and all  agreements,
documents,  obligations,  and transactions  herein  contemplated  have been duly


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authorized  by all necessary  corporate  action on the part of each Borrower and
are not  inconsistent  with  the  Articles  of  Incorporation,  By-Laws,  or any
resolution  of the  Board  of  Directors  of any  Borrower,  do not and will not
contravene  any  provision  of, or constitute a default  under,  any  indenture,
mortgage,  contract,  or other instrument to which any Borrower is a party or by
which any Borrower is bound, and that upon execution and delivery  hereof,  this
Agreement will constitute a legal,  valid, and binding  agreement and obligation
of each Borrower, enforceable in accordance with its terms.

         8.  Conditions  to  Modification.  This  Agreement  shall become valid,
binding, and enforceable only upon satisfaction of the following conditions. All
of the documents referred to below must be in a form and substance acceptable to
Lender.

                  a. This Agreement and all other documents  requested by Lender
         shall have been fully executed and delivered to Lender.

                  b. All of the  documents  requested  by Lender  which  require
         filing or recording  have been properly  filed and recorded so that all
         of the liens and  security  interests  granted to Lender in  connection
         with the Loan will be properly  created and  perfected  and will have a
         priority acceptable to Lender.

         All  conditions  precedent set forth in this Agreement are for the sole
benefit of Lender and may be waived unilaterally by Lender.

         9.  Integrated  Agreement;  Amendment.  This  Agreement  and  the  Loan
Documents,  as modified by this Agreement,  constitute the entire agreements and
understandings  between the parties with respect to the Line of Credit,  and may
not be altered or amended  except by written  agreement  signed by the  parties.
PURSUANT TO UTAH CODE SECTION 25-5-4, BORROWERS ARE NOTIFIED THAT THIS AGREEMENT
AND THE LOAN DOCUMENTS, AS MODIFIED BY THIS AGREEMENT, ARE A FINAL EXPRESSION OF
THE  AGREEMENTS  BETWEEN  LENDER AND BORROWERS AND THESE  AGREEMENTS  MAY NOT BE
CONTRADICTED BY EVIDENCE OF ANY ALLEGED ORAL AGREEMENT.

         10.  This  Agreement  is made  pursuant  to and shall be  construed  in
accordance with the laws of the State of Utah.

                                    LENDER:
                                    -------

                                    ZIONS FIRST NATIONAL BANK


                                    By: /s/ Jennifer T. Sullivan
                                       -----------------------------------------

                                    Title: Asst. Relationship Manager
                                          --------------------------------------


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                                    BORROWERS:
                                    ----------


                                    MERIT MEDICAL SYSTEMS, INC.


                                    By: /s/ Kent Stanger
                                       -----------------------------------------

                                    Title: CFO
                                          --------------------------------------


                                    MERIT MEDICAL INTERNATIONAL, INC.


                                    By: /s/ Kent Stanger
                                       -----------------------------------------

                                    Title: V.P.
                                          --------------------------------------



                                    MERIT HOLDINGS, INC.


                                    By: /s/ Kent Stanger
                                       -----------------------------------------

                                    Title: V.P.
                                          --------------------------------------



                                    SENTIR, INC.


                                    By: /s/ Kent Stanger
                                       -----------------------------------------

                                    Title: SEC
                                          --------------------------------------


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