1. ECG and phonocardiogram were recorded by synchronization.

2. Objective: Explore the value of phonocardiogram exercise test (PCGET) to evaluating cardiac contractility.

3. Therefore, development of phonocardiogram analysis instrument is very important to study the regularity of real-time heart sound and analyze the cardiac contractility variability in various states.

4. It consists of a phonocardiogram sensor, a heart sound collecting and processing circuit, and a computer.

5. Phonocardiogram exercise testing (PCGET) is a method through applying a phonocardiograph to evaluate cardiac contractility and the cardiac reserve.

6. We provided an efficient phonocardiogram(PCG) envelope extraction scheme[sentencedict .com], by utilizing the complexity of dynamical system.

7. Virtual Instrument Collection phonocardiogram source code, is based on the computer sound card, which determined the sound signal and spectrum analysis.

8. The three-dimensional phonocardiogram after wavelet analyzing could describe all the information of frequency domain, time domain and amplitude domain perfectly.

9. The microphone is used in a data acquisition system on a personal computer. The phonocardiogram and speech signals possessing high signal-to-noise ratio can be obtained.

10. Atrial systolic time intervals(ASTI )measured by cardiac impedance plethysmogram, phonocardiogram and electrocardiogram were studied in control and hypertensive subjects.

11. The amplitude of first heart sound is a normal measurement of cardiac contractility, and phonocardiogram (PCG) can be used in the study of cardiac contractility reserve.