Abstract 3756: The Fourth Heart Sound is Associated with Increased Left Ventricular End-Diastolic Elastance

Background: The significance of the fourth heart sound (S4) is unclear. Although the S4 is thought to be associated with a stiff ventricle, prior studies have failed to consistently show an association between abnormal diastolic hemodynamics and the S4. Recently, single-beat estimation of the end-diastolic pressure volume relationship (EDPVR) has been characterized (P = αVβ), allowing measurement of EDPVR in larger numbers of patients. Hypothesis: The S4 is associated with an upward- and leftward-shifted EDPVR, indicative of elevated end-diastolic elastance (stiffness). Methods: Within a 4-hour period, 90 subjects underwent computerized phonocardiography, echocardiography, and left heart catheterization. In each patient, we calculated α and β coefficients to define the non-linear slope of the EDPVR using the single-beat method. Results: The mean age was 62±14 years, 65% were male, 36% had heart failure, and 67% had coronary disease. Phono detected an S4 in 29 patients (32%). S4 patients were older (p=0.04...