Development of an instrument to measure beliefs and attitudes from heart valve disease patients.

The objective of this study was to verify content validity and reliability of "CAV-Instrument" -- an instrument to measure beliefs and attitudes of heart valve disease patients concerning their illness and treatment. The instrument was analyzed by three judges (using predetermined criteria) and submitted to the pretest (n = 17 subjects). The majority of the items were evaluated as adequate regarding their pertinence, clearness and significance regarding the analyzed questions. The pretest showed the necessity for small changes in some statements, which optimized instrument comprehension by the patients. The restructured instrument was applied to 46 patients to verify internal consistency. The whole instrument and most of its scales presented satisfactory internal consistency. It is concluded that the instrument has content validity and is internally consistent, ratifying the adequacy of its application to measure the strength of association among the researched variables.