Spectral analysis of beat-to-beat fluctuations in left ventricular area signals obtained using acoustic quantification

Noninvasive insight into autonomic cardiovascular control is achieved by spectral analysis of fluctuations in heart rate (HR) and blood pressure (BP). Variations in left ventricular cross-sectional area (LVA), can now be noninvasively estimated using echocardiographic acoustic quantification (AQ). In this study, we investigated whether fluctuations in LV dimensions can be subjected to spectral analysis, and whether their power spectra can improve the understanding of the control mechanisms of the heart. Three simultaneous signals, ECG, BP, LVA, were acquired from 30 healthy volunteers (mean age 36±18). Spectral analysis was performed using FFT on 125 sec traces. Our results show that fluctuations in LVA are detectable, steady and quantifiable. Their power spectra (PS) have general features similar to HR and BP PS. Investigation of LVA signals may thus provide information about the control of cardiac mechanical function