Evaluation of the Severity of Chronic Heart Failure by the Reactivity of Peripheral Vessels.

Abstract

We developed a method to evaluate the severity of chronic cardiac failure by Doppler image analysis. Doppler images of the whole arterial lumen were consecutively recorded on video tape and the power spectrum (sum of intensity multiplied by frequency) of each frame was considered as an index of the blood flow volume (VI). The right brachial artery was occluded for 15-60 seconds by a occluding cuff, and was released quickly. The VI was determined until the VI returned to the level at rest and total VI was calculated as an O2 repayment. The O2 repayment rate (R-Rate) was calculated as a ratio of the O2 repayment divided by total VI during interruption. The cardiac function was evaluated by sub-maximal exercise using bicycle ergometer and was compared with the R-Rate. The subjects were 22 patients (18 males and 4 females) with chronic cardiac failure of NYHA class I (9), class II (6), class III (4), class IV (3) and 12 healthy controls. R-Rate was almost unchanged by the duration of occlusion and showed positive correlation with exercise capacity. R-Rate decreased as the class of NYHA advanced. In conclusion, determination of reactive hyperemia can be used for objectively evaluating the severity of cardiac failure. Doppler sonography; cardiac failure; reactive hyperemia; peripheral circulation

Evaluation of Carotid Atherosclerosis from the Perspective of Blood Flow Reflection

“…For this reason, an index of the elasticity based on blood flow, such as the ratio of diastolic to systolic blood flow (i.e., the b value determined by Duplex echogram), is not often used. To address these concerns, we developed a new method and applied it clinically using an image-processing technique on Doppler wave profiles to measure blood flow accurately (13,14). The sampling rate of this system was set at 128Hz and we divided the wave profile of each beat into 512 divisions for FFT analysis of one cardiac cycle to avoid the aliasing effect because the frequency of fluctuation is expected to be 0.5-15Hz.…”

“…Each image of the velocity distribution pattern was recorded for 20-30 s using an ultrasound sonogram (Aloka 5500-SSD, Aloka Co., Tokyo, Japan). The change in the amount of blood flow at the carotid artery was then calculated by computerized image processing with a sampling rate of 128Hz; this rate was set in the equipment (13,14). The wave profile of each beat was divided into 512 segments, processed with fast Fourier transform (FFT), and displayed up to 10 time-components of base frequency (f1), 1 cardiac cycle being the basic frequency.…”

Circadian Variation of the Myocardial Ischemic Threshold in Patients with Ischemic Heart Disease

“…A method was developed for counting characteristic walking motions using the accelerometer and converting these data into a walk rate per minute. A heart rate loop with the ST segment was recorded for each period of walking, and the myocardial ischemic threshold was defined as the HR at the point that ischemic ST depression began, with a simultaneous recording of the walking rate (13)(14)(15)(16). Variation of HR at the ischemic threshold over 24 hours was demonstrated by linear regression analysis of these data.…”

Flow-Mediated Vasodilation and Reactive Hyperemia Index in Heart Failure with Reduced or Preserved Ejection Fraction

“…It is important to note that HFpEF differs from HF with reduced ejection fraction (HFrEF) regarding the pathophysiology and clinical significance (Bhatia et al 2006;Lee et al 2009). Vascular endothelial dysfunction is associated with the pathogenesis and progression of HF (Ino-oka et al 2001;Marti et al 2012). Several studies using flow-mediated vasodilation (FMD), which represents vascular endothelial function of a conduit artery, have demonstrated that endothelial dysfunction is associated with symptom severity and clinical outcomes in patients with HF (Fischer et al 2005;Meyer et al, 2005;Katz et al 2005).…”