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A relative value method for measuring and evaluating cardiac reserve
Shouzhong Xiao1, Xingming Guo, Xiaobo Sun
1Biomedical Engineering Department, Chongqing University, Chongqing 400044, China. xiaosz@cq.cnuninet.net
Insights
New indicators derived from heart sound amplitude, including cardiac contractility change trend (CCCT), can effectively evaluate cardiac function and reserve mobilization. These novel metrics offer insights into cardiac health beyond traditional measures.
Area of Science:
- Cardiology
- Biomedical Engineering
- Physiology
Background:
- Absolute first heart sound (S1) amplitude is limited in evaluating cardiac contractility.
- Previous studies established a link between S1 amplitude and cardiac contractility.
- Relative value indicators are needed for accurate cardiac function assessment.
Purpose of the Study:
- To develop and validate novel indicators for assessing cardiac contractility and function.
- To explore the utility of relative heart sound amplitude ratios and exercise-induced changes.
- To establish new methods for evaluating cardiac reserve and load.
Main Methods:
- Developed four indicators: Cardiac Contractility Change Trend (CCCT) after exercise (CCCT(1/4), CCCT(1)), S1/S2 amplitude ratio, T1/M1 amplitude ratio, and Diastolic/Systolic duration ratio (D/S).
- Collected data from a diverse group of volunteers undergoing exercise protocols.
- Measured S1 and S2 amplitudes at rest and during varying exercise workloads.
Main Results:
- CCCT(1/4) = 6.36 ± 3.01 (n=67), CCCT(1) = 10.36 ± 4.2 (n=33).
- S1/S2 ratio = 1.89 ± 0.94 (n=140), T1/M1 ratio = 1.44 ± 0.99 (n=144), D/S ratio = 1.68 ± 0.27 (n=172).
- Statistically significant values were obtained for all devised indicators.
Conclusions:
- CCCT indicators (CCCT(1/4), CCCT(1)) show promise for evaluating cardiac contractility and reserve mobilization.
- S1/S2 ratio may help assess hypotension factors.
- T1/M1 ratio is useful for right heart load assessment.
- D/S ratio aids in evaluating diastolic cardiac blood perfusion time.
Background:
Although a very close relationship between the amplitude of the first heart sound (S1) and the cardiac contractility have been proven by previous studies, the absolute value of S1 can not be applied for evaluating cardiac contractility. However, we were able to devise some indicators with relative values for evaluating cardiac function.
Methods:
Tests were carried out on a varied group of volunteers. Four indicators were devised: (1) the increase of the amplitude of the first heart sound after accomplishing different exercise workloads, with respect to the amplitude of the first heart sound (S1)recorded at rest was defined as cardiac contractility change trend (CCCT). When the subjects completed the entire designed exercise workload (7000 J), the resulting CCCT was defined as CCCT(1); when only 1/4 of the designed exercise workload was completed, the result was defined as CCCT(1/4). (2) The ratio of S1 amplitude to S2 amplitude (S1/S2). (3) The ratio of S1 amplitude at tricuspid valve auscultation area to that at mitral auscultation area T1/M1 (4) the ratio of diastolic to systolic duration (D/S). Data were expressed as mean +/- SD.
Results:
CCCT(1/4) was 6.36 +/- 3.01 (n = 67), CCCT(1) was 10.36 +/- 4.2 (n = 33), S1/S2 was 1.89 +/- 0.94 (n = 140), T1/M1 was 1.44 +/- 0.99 (n = 144), and D/S was 1.68 +/- 0.27 (n = 172).
Conclusions:
Using indicators CCCT(1/4) and CCCT(1) may be beneficial for evaluating cardiac contractility and cardiac reserve mobilization level, S1/S2 for considering the factor for hypotension, T1/M1 for evaluating the right heart load, and D/S for evaluating diastolic cardiac blood perfusion time.
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