title: Evaluation of the reproducibility and accuracy of apex beat measurement in the detection of echocardiographic left ventricular dilation.
abstract: OBJECTIVE
  To develop a standardized method for measuring the width of the apex beat and to determine its precision and accuracy in detecting echocardiographically determined left ventricular dilation.
  
  
  METHODS
  In the reproducibility study, two cardiologists blinded to each other's findings measured the apex beat. To determine accuracy, blind, independent assessment of apex beat measurement was compared with left ventricular enlargement determined by echocardiogram.
  
  
  METHODS
  One hundred and four patients referred for echocardiogram for a wide variety of suspected cardiac abnormalities.
  
  
  METHODS
  The apex beat was measured with patients in a 45 degrees left lateral decubitus position; medial and lateral aspects of the impulse and the width were identified using electrocardiographic callipers. Echocardiographic left ventricular dilation was defined as a measure exceeding the 95% prediction limits as determined for the patient's age and body surface area.
  
  
  RESULTS
  The intraclass correlation measuring agreement on apex beat size between two cardiologists in 13 patients was 0.95. Of the 104 patients, 57 had a measurable apex beat of whom 50 had a technically adequate echocardiogram. The sensitivity of the measurement, using a cut-point of 40 mm, was 0.48 and the specificity 0.96.
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, McMaster University Medical Centre, Hamilton, Ontario.
authors.forename: A L
authors.initials: AL
authors.lastname: Dans
authors.forename: E F
authors.initials: EF
authors.lastname: Bossone
authors.forename: G H
authors.initials: GH
authors.lastname: Guyatt
authors.forename: E L
authors.initials: EL
authors.lastname: Fallen
mesh_terms: D000367:Age Factors; D000368:Aged; D001830:Body Surface Area; D002311:Cardiomyopathy, Dilated / Q000000981:diagnostic imaging* / Q000503:physiopathology; D004311:Double-Blind Method; D004452:Echocardiography; D005260:Female; D006339:Heart Rate; D006801:Humans; D007702:Kinetocardiography; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000503:physiopathology