Diastolic-systolic lag in spontaneous arterial blood pressure oscillations in normal and pathological subjects

In order to assess the timing relationship between corresponding oscillatory components of systolic (SAP) and diastolic (DAP) arterial pressure, 8 min resting recordings of SAP and DAP were analyzed in 23 post-myocardial infarction (MI) patients, 24 chronic heart failure (CHF) patients showing a periodic breathing pattern (CHF-PB), 15 CHF patients with normal breathing (CHF-NB) and 18 controls. The coherence and phase spectrum between SAP and DAP were estimated and from the latter the time delay at the VLF, LF and HF components derived. A consistent delay between DAP and SAP in the VLF band was found in all 4 groups considered. The delay was higher in CHF patients, with mean value /spl ap/3.5 s, and lower in MI patients (1.7 s, p<0.01) and control subjects (2.5 s, NS). A much smaller but significant delay in the range 0.5-0.8 s was observed in the LF band. In the HF band the delay was centered around zero. The delay between DAP and SAP fluctuations in the VLF and LF bands is a common feature of both healthy and cardiovascular diseased subjects and thus represents a physiological rather than a pathological phenomenon.