The Fourth Heart Sound-A Premature Requiem?

Association of the Fourth Heart Sound With Increased Left Ventricular End-Diastolic Stiffness

“…The importance of the S 4 has been debated in the past; some believe that the S 4 is present in the majority of elderly, thereby decreasing its utility (6,7,9). Our study supports the concept that the S 4 is an abnormal finding, and it is the first S 4 study to our knowledge which quantifies LV diastolic stiffness using various different parameters.…”

“…Because the S 4 has been associated with conditions that cause left ventricular (LV) diastolic stiffness such as aortic stenosis, ischemia, and left ventricular hypertrophy (6,7), many believe that the S 4 is due to decreased compliance, although this has never been proven. Because there is controversy regarding the clinical utility of the S 4 (8,9), and because its association with diastolic stiffness has never before been shown, we sought to prove the hypothesis that the S 4 is associated with increased end-diastolic stiffness.…”

The genesis of the third and fourth heart sounds. A pressure-flow study in dogs.

“…Though various theories have been advanced regarding the genesis ofthese sounds, the fundamental mechanism of production is still unknown (1)(2)(3)(4)(5)(6)(7). According to Rushmer (4), heart sounds should be considered as vibrations of the cardiohemic system due to acceleration or deceleration of flow.…”

Relation of P-S4 interval to left ventricular end-diastolic pressure.

“…Traditionally, the atrial sound has been felt by some to be a reliable physical sign of ventricular dysfunction. [2][3][4][5] Others, however, felt that the mere presence of an atrial sound was of little diagnostic value, since it was frequently recorded by phonocardiograms in normal patients as well as in those with ventricular dysfunction.67 The temporal relation of the atrial sound to the electrocardiogram and first heart sound (Si) has been found to vary with clinical changes in patients with ischaemic heart disease and hypertension. Altered left ventricular pressure volume relations have been implicated as the common denominator in the production of the pathological fourth heart sound.45 More specifically, it has been postulated that decreasing left ventricular distensibility (as reflected by increased left ventricular end-diastolic pressure) is associated with decreasing P wave to atrial sound interval (P-S4) and that it is this mechanism which leads to changes in the P-S4 interval.410-13 It has been shown by McLaurin et al, 14 Barry We performed simultaneous phonocardiography and left ventricular pressure measurements and then used atrial pacing in patients with coronary disease to study the relation of atrial activation, timing of S4 generation, and left ventricular pressure at enddiastole.…”