Implications of an audible third heart sound in evaluating cardiac function

Area of Science:

• Cardiology
• Clinical Medicine
• Diagnostic Tools

Background:

• Heart failure diagnosis relies on clinical evaluation and advanced imaging.
• Third heart sounds (S3) are potential indicators of ventricular dysfunction.
• Radionuclide ventriculography provides quantitative assessment of systolic and diastolic function.

Purpose of the Study:

• To compare the diagnostic accuracy of auscultatory third heart sounds (S3) with radionuclide ventriculography in assessing ventricular function.
• To determine the sensitivity, specificity, and predictive values of S3 for abnormal systolic and diastolic function in heart failure patients.

Main Methods:

• Prospective study comparing cardiac auscultation for S3 detection with radionuclide ventriculography.
• Analysis included 49 adult men with chronic, nonvalvular heart failure.
• Ventricular function assessed via ejection fraction, peak ejection rate, and peak filling rate.

Main Results:

• 45% of heart failure patients had an S3 present on examination.
• S3 presence correlated with reduced ejection fraction and impaired diastolic function (lower peak filling rate).
• S3 showed high specificity (90%) and positive predictive value (95%) for abnormal systolic function (EF < 50%), but lower sensitivity (51%).
• For ejection fraction < 30%, S3 sensitivity was 78% and specificity 88%.

Conclusions:

• An S3 is a significant clinical sign highly predictive of abnormal ejection fraction in heart failure.
• The absence of an S3 does not exclude mild systolic dysfunction.
• Auscultation for S3 remains a valuable, albeit imperfect, tool in the evaluation of heart failure patients.