Hemodynamic Correlates of the Third Heart Sound and Systolic Time Intervals

Abstract

Bedside diagnostic tools remain important in the care of patients with heart failure. Over the past two centuries, cardiac auscultation and phonocardiography have been essential in understanding cardiac pathophysiology and caring for patients with heart disease. Diastolic heart sounds (S3 and S4) and systolic time intervals have been particularly useful in this regard. Unfortunately, auscultation skills have declined considerably, and systolic time intervals have traditionally required carotid pulse tracings. Newer technology allows the automated detection of heart sounds and measurement of systolic time intervals in a simple, inexpensive, noninvasive system. Using the newer system, the authors present data on the hemodynamic correlates of the S3 and abnormal systolic time intervals. These data serve as the foundation for using the system to better understand the test characteristics and pathophysiology of the S3 and systolic time intervals, and help to define their use in improving the bedside diagnosis and management of patients with heart failure.

Haemodynamic monitoring of cardiac status using heart sounds from an implanted cardiac device

“…14 Prior studies have shown that STIs measured exclusively using HSTIs without a simultaneous carotid pulse tracing bear a consistent relationship to true STIs. 8,29 Just like with true STIs, 13 our results show a significant negative correlation of contractility to HSPEP and HSPEP/HSET, but poorer correlation to HSET. 13 Together with S1 amplitude, HSTIs may track contractile function from an implanted device providing an ideal complement to congestion sensors such as impedance and S3 amplitude in monitoring of ambulatory HF patients.…”

“…The third heart sound (S3), which is caused by rapid deceleration of the blood against a stiff ventricle during early diastolic filling, is regarded as one of the earliest signs of HF. 5,6 The S3 is also known to be moderately sensitive but highly specific to elevated left ventricular (LV) filling pressures 7,8 and predictive of 1-year mortality. 9 An implanted device-based S3 sensor can serve as a useful surrogate for intracardiac haemodynamics 10 without requiring an additional procedure to implant a dedicated intravascular device.…”

Assessment of systolic and diastolic function in clinically healthy horses using ambulatory acoustic cardiography

“…However, one would expect that EMAT, lasting from onset of the electrocardiographic Q wave to the start of isovolumic contraction (which is timely related to the first heart sound, S1), is shorter than PEP, which lasts from onset of Q to the start of ventricular ejection (corresponding to aortic valve opening and onset of aortic blood flow). Conversely, LVST, lasting from the start of isovolumic contraction (S1) to the end of ejection (which is timely related to the second heart sound, S2) should be longer than LVET, which lasts from begin to end of ventricular ejection (aortic valve opening to closure) [21,27]. This is concurrent with recent studies using tissue Doppler imaging for assessment of left ventricular function in horses, in which reported PEP (127 AE 25.3 ms; 121 AE 14.1 ms) was longer than EMAT and LVET (404 AE 18.9 ms; 421 AE 24.7 ms) was shorter than LVST reported in this study, respectively [28,39].…”

“…In people, strong correlations were found between the strength of S3 and left ventricular (LV) end-diastolic filling pressures and between EMAT and the maximum rate of systolic LV pressure change (LV dp/dt max ) and LV ejection fraction, respectively. Consequently, EMAT, S3 and SDI were shown to be highly specific to diagnose LV dysfunction and heart failure [16,27].…”

Noninvasive Detection of Left-Ventricular Systolic Dysfunction by Acoustic Cardiography in Atrial Fibrillation

“…Measuring systolic time intervals and diastolic heart sounds, acoustic cardiography allows reliable assessment of hemodynamics [7–10]. Parameters produced by this technique include those to assess systolic function [11] including EMAT (electrical mechanical activation time, Q wave onset to the S1 interval), the presence of a third heart sound (S3), and SDI (systolic dysfunction index, a combination of EMAT, S3, QRS duration and QR interval). This diagnostic method is particularly appropriate in environments, where echocardiography or invasive assessment of LV function is not available [12] or when serial measurements are desired.…”