Physiology of the third heart sound: novel insights from tissue Doppler imaging.
BACKGROUND
The third heart sound (S(3)) is thought to be caused by the abrupt deceleration of left ventricular (LV) inflow during early diastole, increased LV filling pressures, and decreased LV compliance. We sought to determine whether the ratio of early mitral inflow velocity to diastolic velocity of the mitral annulus (E/E') could confirm the proposed mechanism of the S(3).


METHODS
A total of 90 subjects underwent phonocardiography, echocardiography, tissue Doppler imaging, and left-sided heart catheterization.


RESULTS
Phonocardiography detected an S(3) in 21 patients (23%). Subjects with an S(3) had lower ejection fraction (P = .0006) and increased E deceleration rate (P < .0001), E/E' (P < .0001) and filling pressures (P < .0001). The phonocardiographic S(3) confidence score correlated with E/E' (r = 0.46; P < .0001) and E deceleration rate (r = 0.43, P = .0001). Of the echocardiographic variables, only E/E' was independently associated with the S(3) confidence score (P = .009), independently of invasively determined LV filling pressures (P = .001).


CONCLUSIONS
The most important determinants of the pathologic S(3) are an increased deceleration rate of early mitral inflow, elevated LV filling pressures, and abnormal compliance of the myocardium as measured by tissue Doppler imaging.
Division of Cardiology, Department of Medicine, University of California, San Francisco, California, USA.
Sanjiv J
SJ
Shah
Gregory M
GM
Marcus
Ivor L
IL
Gerber
Barry H
BH
McKeown
Joshua C
JC
Vessey
Mark V
MV
Jordan
Michele
M
Huddleston
Elyse
E
Foster
Kanu
K
Chatterjee
Andrew D
AD
Michaels
D015150:Echocardiography, Doppler / Q000379:methods*; D005260:Female; D006347:Heart Sounds; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008944:Mitral Valve Insufficiency / Q000175:diagnosis* / Q000503:physiopathology*; D010701:Phonocardiography / Q000379:methods*; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000503:physiopathology*