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Color Doppler images of aortic regurgitation (AR) flow acceleration, flow convergence (FC), and the vena contracta (VC) have been reported to be useful for evaluating severity of AR. However, clinical application of these methods has been limited because of the difficulty in clearly imaging the FC and VC. This study aimed to explore new windows for imaging the FC and VC to evaluate AR volumes in patients and to validate this in animals with chronic AR. Forty patients with AR and 17 hemodynamic states in 4 sheep with strictly quantified AR volumes were evaluated. A Toshiba SSH 380A with a 3.75-MHz transducer was used to image the FC and VC. After routine echo Doppler imaging, patients were repositioned in the right lateral decubitus position, and the FC and VC were imaged from high right parasternal windows. In only 15 of the 40 patients was it possible to image clearly and measure accurately the FC and VC from conventional (left decubitus) apical or parasternal views. In contrast, 31 of 40 patients had clearly imaged FC regions and VCs using the new windows. In patients, AR volumes derived from the FC and VC methods combined with continuous velocity agreed well with each other (r = 0.97, mean difference = -7.9 ml +/- 9.9 ml/beat). In chronic animal model studies, AR volumes derived from both the VC and the FC agreed well with the electromagnetically derived AR volumes (r = 0.92, mean difference = -1.3 +/- 4.0 ml/beat). By imaging from high right parasternal windows in the right decubitus position, complementary use of the FC and VC methods can provide clinically valuable information about AR volumes.

P with chronic congestive heart failure (CHF) have fatigue and dyspnea with exercise intolerance and a poor prognosis. Fluid retention along with peripheral vasoconstriction and reduced skeletal muscle perfusion provide the physiologic basis for the symptoms. Neurohormonal modulation by norepinephrine (NE), atrial natriuretic peptide (ANP), and brain natriuretic peptide (BNP) are heavily involved in the clinical manifestations of patients with CHF. We have recently reported that posture largely affects the autonomic nervous activity in patients with CHF. In the right lateral decubitus position, sympathetic tone decreased, whereas parasympathetic activity increased. In the present study, we hypothesized that neurohormonal environment of patients with CHF is ameliorated in the right lateral decubitus position because these patients prefer the position. • • • The study group consisted of 14 patients (8 men and 6 women, mean age 72 14 years) with CHF due to coronary artery disease (Table 1). Three patients had New York Heart Association functional class II CHF, 10 had class III, and 1 had class IV. The mean left ventricular ejection fraction was 39 18%. No patient had diabetes mellitus. A constant diuretic, digitalis, calcium antagonist, nitrate, angiotensin-converting enzyme inhibitor, and angiotensin II antagonist dosing regimen was continued. However, -blocking therapy had been withdrawn at least 7 days earlier. Eight ageand sex-matched New York Heart Association functional class I patients with normal left ventricular function (5 men, 3 women, mean age 69 13 years) were selected as the control group. In the early morning, each of the 3 positions (left lateral decubitus, supine, right lateral decubitus) was maintained for 1 hour before blood samples were drawn from a peripheral vein through an indwelling catheter. The order of each position was randomized. Plasma NE, ANP, and BNP levels were then measured by radioimmunoassay. All patients provided informed consent to the protocol, which was approved by the human subjects review committee of Takeda Hospital. Data are expressed as mean SD. Comparisons of variables between the 2 groups were conducted by Fisher’s exact test or unpaired Student’s t test. Multiple comparisons were performed by 2-way analysis of variance, followed by the Tukey-Kramer test for each parameter among the 3 recumbent positions of both groups of patients. Results were considered significant at p 0.05. Plasma NE concentrations were higher in patients with CHF than in those with normal LV function (Figure 1A). In addition, plasma NE concentrations were significantly lower in the right lateral decubitus position than those in the left lateral decubitus and supine positions. Plasma ANP and BNP concentrations were also higher in patients with CHF than in those with normal left ventricular function (Figures 1B and 1C). In addition, in patients with CHF, plasma ANP concentrations were higher in the right lateral decubitus position than those in the left lateral decubitus and supine positions, although plasma BNP levels did not significantly differ among the 3 recumbent positions. In patients with normal left ventricular function, there were no significant differences in these From the Departments of Cardiovascular Medicine and Cardiovascular Surgery, Kyoto University, Kyoto; Division of Cardiology, Takeda Hospital, Kyoto; Division of Cardiology, National Cardiovascular Center, Osaka; Department of Medicine, Division of Cardiology, Kitano Hospital, The Tazuke Kofukai Medical Research Institute, Osaka; Second Department of Internal Medicine, Kansai Electric Power Hospital, Kanasi; and College of Medical Technology, Kyoto University, Kyoto, Japan. Dr. Fujita’s address is: College of Medical Technology, Kyoto University, 53 Kawaharacho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan. E-mail: mfujita@kuhp.kyoto-u.ac.jp. Manuscript received June 29, 2001; revised manuscript received and accepted September 25, 2001. TABLE 1 Clinical Characteristics of Eight Patients With Normal Left Ventricular Function and 14 Patients With CHF

Patients with coronary artery disease (CAD) have depressed vagal modulation. Because the mortality risk from acute myocardial infarction is lower in patients with higher vagal modulation, methods that can increase vagal modulation are desirable for patients with CAD. The right lateral decubitus position has been found, in young healthy subjects, to lead to the highest vagal modulation among 3 recumbent positions using spectral heart rate variability (HRV) analysis. This study investigated which recumbent position can give rise to the highest vagal modulation in patients with severe CAD. Twenty-seven patients scheduled for coronary artery bypass graft surgery and 17 patients with angiographically normal coronary arteries were studied. Spectral HRV analysis was performed in random order on these patients in 3 recumbent positions: namely, the supine, left lateral decubitus, and right lateral decubitus positions. Normalized high-frequency power was the highest, whereas normalized low-frequency power and low/high-frequency power ratio in the right lateral decubitus position were the lowest, among the 3 recumbent positions in both groups of patients. The lower the normalized high-frequency power in the supine or left lateral decubitus position, the higher the increase in the normalized high-frequency power when the position was changed from supine or left lateral decubitus to right lateral decubitus in patients with severe CAD. Right lateral decubitus position can lead to the highest vagal modulation and the lowest sympathetic modulation among the 3 recumbent positions in patients with severe CAD. Therefore, the right lateral decubitus position can be used as an effective physiologic vagal enhancer in patients with severe CAD.