Heart rate--left ventricular ejection time relations. Variations during postural change and cardiovascular challenges.

Abstract

Regression equations for heart rate (HR)-ejection time (LVET) (Kesteloot and Denef, 1970;Benchimol and Matsuo, 1971;Parisi, Salzman and Schechter, 1971;Takahashi and Moritz, 1972;Matsuura and Goodyer, 1973). Because LVET is dependent on heart rate (HR) (Braunwald, Sarnoff, and Stainsby, 1958;Jones and Foster, 1964) it is common practice to correct LVET for HR based on linear regression equations. The corrected value, the ejection time index (ETI), is calculated as follows: ETI = LVET-b(HR), where b is the slope of the regression analysis of LVET on HR. By employing the intercept (a) of the regression equation, it is also possible to predict LVET for a given HR using the formula LVET= a+b(HR).While LVET is HR dependent, the exact relation varies according to factors such as age, sex, and health status (Weissler, Harris, and White, 1963;Harris et al., 1964;Spodick and Kumar, 1968;Kesteloot and Denef, 1970;Willems et al., 1970;Takahashi and Moritz, 1972). Physiological challenges such as supine (Lindquist, Spangler, and Blount, 1973;Maher et al., 1974) and upright (Lance and Spodick, 1976) bicycle exercise also effect differences in the HR-LVET relation. Demonstration of the HR-LVET relations under the different conditions in which LVET must be corrected for HR are of both theoretical and practical importance. They are of theoretical importance as an expression of the underlying physiology of these conditions. They are of practical importance as appropriate factors for correcting data.To obtain a range of LVET behaviour, we chose

Assessment of Systolic Ejection Time as a Hemodynamic Marker of Incipient Bradycardic Vasovagal Syncope. A Pilot Study

“…Thus, LVET can be regarded as one determinant of SV. In standard physiologic conditions, LVET is HR dependent, decreasing when HR increases and vice versa 18 . As the incipient syncope approaches, HR starts to decrease, SV no longer increases, and ET% also changes accordingly with SV.…”

“…In standard physiologic conditions, LVET is HR dependent, decreasing when HR increases and vice versa. 18 As the incipient syncope approaches, HR starts to decrease, SV no longer increases, and ET% also changes accordingly with SV. The combined decrease of HR, SV, and ET% is a specific marker of the immediate risk of syncope-the decrease in HR is no longer compensated by the increase in SV and so by the increase in ET%.…”

Left ventricular systolic dysfunction in a patient with accidental hypothermia: a case report

“…Ejection time is a hemodynamic parameter used to compute stroke volume [5] and is inversely proportional to heart rate [6]. Lance and Spodick described the relationship between heart rate and left ventricular ejection time during postural change.…”

“…Lance and Spodick described the relationship between heart rate and left ventricular ejection time during postural change. According to their report, the ejection time is 0.32 to 0.34 seconds when the heart rate is 40 beats per minute [6]. Teodorescu et al .…”

Short- and Long-Term Variation of Systolic and Diastolic Time Intervals at Rest and during Dynamic Exercise in Healthy Subjects

“…It is well known that postural changes and cardiovascu lar stress conditions affect the regression equations for the heart rate-time interval relationship [19][20][21], In the present study, Weisslers [15] heart rate correction factors for resting, supine subjects were used for QS2 and LVET, thus introducing a small error in the calculations. How ever, posture, exercise heart rate and timing of the tests were strictly standardized in the present study.…”