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Effect of left ventricular contractile performance on passive left atrial filling--clinical study using radionuclide
K Fujii1, M Ozaki, T Yamagishi
1Second Department of Internal Medicine, Yamaguchi University School of Medicine, Ube, Japan.
Insights
Left ventricular (LV) contraction significantly influences left atrial (LA) filling. Enhanced LV contractile performance directly correlates with increased LA peak filling rates, highlighting LV
Area of Science:
- Cardiology
- Physiology
Background:
- Quantitative measurement of atrial function is limited.
- Understanding the interplay between ventricular contraction and atrial filling is crucial.
Purpose of the Study:
- To determine the interaction between left ventricular (LV) contraction and left atrial (LA) filling.
- To investigate the influence of LV contractile performance on LA passive filling.
Main Methods:
- Gated radionuclide angiography in 30 normal subjects.
- Simultaneous acquisition of LV and LA time-activity curves.
- Calculation of LV ejection fraction, LV peak ejection rate (LVPER), LA fractional emptying, and LA peak filling rate (LAPFR).
Main Results:
- LVPER and LAPFR occurred simultaneously in all subjects.
- A significant positive correlation (r = 0.81, p < 0.001) was observed between LVPER and LAPFR.
- LA filling rate was strongly affected by LV contractile performance.
Conclusions:
- Left ventricular contractile performance plays a key role in determining left atrial passive filling during ventricular systole.
- Radionuclide angiography provides quantitative measures of atrial function and its interaction with ventricular dynamics.
Abstract:
Many invasive and noninvasive methods have been used to study the cardiac atria; however, few allow quantitative measurement of atrial function. To determine the interaction between left ventricular (LV) contraction and left atrial (LA) filling, gated radionuclide angiography was conducted in 30 normal subjects (24 men and 6 women, mean age 58 +/- 10 years, range 26-68). LV and LA time-activity curves and their first-derivative curves were obtained simultaneously by using the method of Bough et al. The LV ejection fraction (64 +/- 18%) and LV peak ejection rate (LVPER; 3.42 +/- 0.27 EDV/s) were computed from these curves. As indices of LA filling, LA fractional emptying (38 +/- 12%) and LA peak filling rate (LAPFR; 2.86 +/- 0.17 LAVmax/s)--the latter being defined as the peak rate of LA filling during the LA filling phase--were also computed from these curves. In all subjects, the timing of the LVPER coincided with the occurrence of LAPFR, and there was a significant positive correlation between the LVPER and LAPFR (r = 0.81, p < 0.001), indicating that the LAPFR was strongly affected by the degree of LVPER. Thus, these results indicate that LV contractile performance plays an important role in determining LA passive filling during ventricular systole.