Author Contributions: Dr Spyt had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Doukas, Samani, Chin, Stafford, Spyt.
Acquisition of data: Doukas, Oc.
Analysis and interpretation of data: Doukas, Samani, Alexiou, Ng, Spyt.
Drafting of the manuscript: Doukas, Samani, Alexiou, Oc.
Critical revision of the manuscript for important intellectual content: Samani, Alexiou, Chin, Stafford, Ng, Spyt.
Statistical analysis: Alexiou, Oc.
Obtained funding: Doukas, Samani, Stafford, Spyt.
Administrative, technical, or material support: Doukas, Samani, Ng, Spyt.
Study supervision: Samani, Alexiou, Chin, Spyt.
Financial Disclosures: None reported.
Funding/Support: The study was funded through a project grant by the British Heart Foundation. Dr Samani holds a British Heart Foundation Chair in Cardiology.
Role of the Sponsor: The sponsor had no role in study design, data collection, data analysis, data interpretation, writing of the report, or the decision to submit the report for publication.
Acknowledgment: We thank Nick Taub, research fellow in Medical Statistics, for providing his expert statistical advice and Loraine Ricketts, senior echocardiographer, Julie Hayton, chief CCSO adult echocardiography, and Bahar Oc, anesthetist, for performing and analyzing the echocardiograms.