title: Improved detection of ischemic heart disease by combining high-frequency electrocardiogram analysis with exercise stress echocardiography.
abstract: OBJECTIVE
  Because the exercise treadmill test (ETT) based on ST-segment analysis is limited due to low sensitivity and specificity, there has been an interest in the additional analysis of high-frequency components of QRS (HFQRS) for the detection of coronary artery disease (CAD). We sought to evaluate the feasibility and clinical usefulness of HFQRS analysis during exercise stress echocardiography (ESE).
  
  
  METHODS
  We evaluated 175 patients (age 57±9,118 men) who performed ESE and either coronary computed tomographic angiography or coronary angiography. ETT was performed using the HyperQ stress system for both conventional ST-segment analysis and HFQRS intensity analysis.
  
  
  RESULTS
  Thirty-two patients (31%) had significant CAD. The sensitivity and specificity of HFQRS analysis were 68.8% and 74.8%, respectively. The combined model, including HFQRS analysis and ESE, provided the best diagnostic accuracy, with the area under the receiver-operating characteristics curve (AUC) of 0.948 {95% confidence interval (CI)=0.913-0.984} compared with ST-segment analysis (AUC 0.679, 95% CI=0.592-0.766).
  
  
  CONCLUSIONS
  HFQRS analysis during ESE is feasible and may provide additional diagnostic information for the detection of significant CAD.
authors.affiliation: Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Jin-Oh
authors.initials: JO
authors.lastname: Choi
authors.forename: Sung-A
authors.initials: SA
authors.lastname: Chang
authors.forename: Sung Ji
authors.initials: SJ
authors.lastname: Park
authors.forename: Sang-Chol
authors.initials: SC
authors.lastname: Lee
authors.forename: Seung Woo
authors.initials: SW
authors.lastname: Park
keywords: Coronary artery disease; Echocardiography, stress; Electrocardiography; Treadmill test