Accepted for Publication: June 21, 2013.
Published Online: September 9, 2013. doi:10.1001/jamainternmed.2013.10074.
Study concept and design: de Mulder, Umans, Cornel, Oemrawsingh, Akkerhuis, Boersma.
Acquisition of data: de Mulder, Cornel, van der Zant, Stam.
Analysis and interpretation of data: de Mulder, Umans, Cornel, Stam, Boersma.
Drafting of the manuscript: de Mulder, Umans, Boersma.
Critical revision of the manuscript for important intellectual content: All authors.
Obtained funding: Boersma.
Administrative, technical, or material support: de Mulder, Umans, van der Zant, Stam.
Study supervision: Umans, Cornel, Stam, Boersma.
Conflict of Interest Disclosures: None reported.
Funding/Support: This work was funded by grant No. FI 0610 from the Foreest Medical School, Alkmaar, the Netherlands, and grant No. 07101 from the Netherlands Heart Institute, Interuniversitair Cardiologisch Instituut Nederland.
Role of the Sponsors: The sponsors had no influence on design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript.