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They're still worth listening for, but don't be misled if you can't hear them: The absence of S3 and S4 isn't enough to rule out ventricular dysfunction, according to a recent study. Clinicians have traditionally relied on auscultation of S3 and S4 sounds to diagnose left ventricular dysfunction, but the diagnostic value of these findings has been questioned-especially given the variation in clinicians' ability to hear extra heart sounds.


Studying 90 adults undergoing elective left-sided cardiac catheterization, researchers found that detecting S3 or S4 wasn't a sensitive marker of left ventricular dysfunction. However, although S3 or S4 weren't always present in patients with heart failure, nearly all of those in whom these sounds were detected had cardiac dysfunction. So the researchers recommend that clinicians still consider auscultation the first step in patient evaluation before ordering more expensive and possibly invasive testing.




Association between phonocardiographic third and fourth heart sounds and objective measures of left ventricular function, JAMA, GM Marcus, et al., May 11, 2005.