title: Performance of phonoelectrocardiographic left ventricular systolic time intervals and B-type natriuretic peptide levels in the diagnosis of left ventricular dysfunction.
abstract: BACKGROUND
  Systolic time intervals measured by echocardiography and carotid artery tracings are validated methods of assessing left ventricular function. However, the clinical utility of phonoelectrocardiographic systolic time intervals for predicting heart failure using newer technology has not been evaluated.
  
  
  METHODS
  We enrolled 100 adult patients undergoing left heart catheterization. Participants underwent computerized phonoelectrocardiographic analysis, left ventricular end-diastolic pressure (LVEDP) measurement, transthoracic echocardiographic measurement of left ventricular ejection fraction (LVEF), and B-type natriuretic peptide (BNP) testing. The heart rate-adjusted systolic time intervals included the time from the Q wave onset to peak S1 (electromechanical activation time, EMAT), Q wave onset to peak S2 (electromechanical systole, Q-S2), and peak S1 to peak S2 (left ventricular systolic time, LVST). Left ventricular dysfunction was defined as the presence of both LVEDP >15 mmHg and LVEF <50%.
  
  
  RESULTS
  EMAT (r =-0.51; P < 0.0001), EMAT/LVST (r =-0.41; P = 0.0001), and Q-S2 (r =-0.39; P = 0.0003) correlated with LVEF, but not with LVEDP. An abnormal EMAT > or =15 (odds ratio 1.38, P < 0.0001) and EMAT/LVST > or =0.40 (OR 1.13, P = 0.002) were associated with left ventricular dysfunction. EMAT > or =15 had 44% sensitivity, 94% specificity, and a 7.0 likelihood ratio for left ventricular dysfunction, while EMAT/LVST > or =0.40 had 55% sensitivity, 95% specificity, and a 11.7 likelihood ratio. In patients with an intermediate BNP (100-500 pg/mL), the likelihood ratio increased from 1.1 using the BNP result alone to 11.0 when adding a positive EMAT test for predicting left ventricular dysfunction.
  
  
  CONCLUSIONS
  Phonoelectrocardiographic measures of systolic time intervals are insensitive but highly specific tests for detecting abnormalities in objective markers of left ventricular function. EMAT and EMAT/LVST provide diagnostic information independent of BNP for detecting patients with left ventricular dysfunction.
authors.affiliation: Division of Cardiology, Department of Medicine, University of California at San Francisco Medical Center, San Francisco, CA, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Moyers
authors.forename: Mia
authors.initials: M
authors.lastname: Shapiro
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Marcus
authors.forename: Ivor L
authors.initials: IL
authors.lastname: Gerber
authors.forename: Barry H
authors.initials: BH
authors.lastname: McKeown
authors.forename: Joshua C
authors.initials: JC
authors.lastname: Vessey
authors.forename: Mark V
authors.initials: MV
authors.lastname: Jordan
authors.forename: Michele
authors.initials: M
authors.lastname: Huddleston
authors.forename: Elyse
authors.initials: E
authors.lastname: Foster
authors.forename: Kanu
authors.initials: K
authors.lastname: Chatterjee
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Michaels
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006328:Cardiac Catheterization; D003430:Cross-Sectional Studies; D004452:Echocardiography; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010701:Phonocardiography / Q000379:methods*; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity; D013599:Systole / Q000502:physiology; D018487:Ventricular Dysfunction, Left / Q000097:blood / Q000175:diagnosis* / Q000503:physiopathology
chemical_list: D020097:Natriuretic Peptide, Brain