Introduction: The interactions between heart and lungs activities are the manifestation of cardioresipratory synchronization. The harmonization between heart pulse and respiratory rate is a true synchronization phenomenon eventhough not the main variable of cardiorespiratory interaction [1]. From the mechanical physic point of view, the neighboring position of heart and lungs, raising the possibility for the interference sound waves to be occure, so that can be considered as the form of cardiorespiratory synchronization too. So far, the interference sounds just considered as noise that must be minimized or removed [2-4]. This research try to give different ways to understand the interference sounds. In this context, will be proved that the interference sounds bring a unique characteristics to the heart sounds. Method: The research was done by analyzing the heart sounds spectral obtained from the hold and free breathing condition. These data were recorded simultaneously with the electrocardiograph (ECG) signal and the respiratory rates, from the healthy male/female in sitting position. The free breathing condition was done for 40 seconds, meanwhile the hold breathing was recorded for 15 seconds. All raw data were obtained from Amit et al. [5]. Result: The spectral analysis for the hold breathing heart sounds shows the phenomenon of phase shifting and the signal missing (Fig. 1). The results of correlation analysis prove that the phase shifting correlate with respiratory cycles, meanwhile the signal missing correlate with the ECG signal. These findings seems to be associate to the hold breathing condition that similar with the maximum inspiration condition. It means that the left ventricular filling volume flows constantly so that the heart sounds on the left area just influence by the variation of constraction-relaxation triggered by the heart electricity. The hold breathing condition is seems like permanent inspiration too because of the subject have filled the lungs as much as possible before holding the breathing. This condition makes the minimum filling volume to trigger the heart valve opening to be delayed. It means that the heart sounds generation become delayed also. Conclusion: The present of phase shifting and signal missing in the recorded heart sounds for the hold breathing condition prove that the interference sounds between heart and lungs do have significant influences to the heart sounds dinamics. Separating the lungs sounds from the heart sounds in the auscultation process will decrease the accuracy of the analysis results.