Performance of phonoelectrocardiographic left ventricular systolic time intervals and B-type natriuretic peptide levels in the diagnosis of left ventricular dysfunction.
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.
Moyers
Brian
B
Division of Cardiology, Department of Medicine, University of California at San Francisco Medical Center, San Francisco, CA, USA.
Shapiro
Mia
M
Marcus
Gregory M
GM
Gerber
Ivor L
IL
McKeown
Barry H
BH
Vessey
Joshua C
JC
Jordan
Mark V
MV
Huddleston
Michele
M
Foster
Elyse
E
Chatterjee
Kanu
K
Michaels
Andrew D
AD
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
D020097:Natriuretic Peptide, Brain