Shingo Kurokawa

Noninvasive evaluation of the ratio of pulmonary to systemic flow in ventricular septal defect by means of Doppler two-dimensional echocardiography

Left ventricular inflow volume (LVIV) and outflow volume (LVOV) were determined by pulsed Doppler echocardiography, and the ratio of pulmonary to systemic flow (Qp/Qs) was estimated as a ratio of LVIV to LVOV (LVIV/LVOV). Seventy-seven patients were studied, 47 control subjects and 30 patients with ventricular septal defect (VSD). LVOV was calculated from the left ventricular ejection flow velocity and left ventricular outflow tract diameter; LVIV was calculated from the transmitral flow velocity and mitral valve motion as traced by M-mode echocardiography. Cardiac input (COin) and cardiac output (COout) were calculated as the product of LVIV or LVOV and heart rate. Cardiac output was also determined by the dye dilution method (COdye) in control subjects. A close correlation was observed between COdye and COin (y = 1.18x - 243, r = 0.85, p less than 0.005, SEE = 1026 ml/min) and COdye and COout (y = 1.16x - 323, r = 0.90, p less than 0.005, SEE = 639 ml/min). LVIV and LVOV were highly correlated in control subjects (y = 0.95x + 5.3, r = 0.94, p less than 0.005, SEE = 6.6 ml). LVIV/LVOV was 0.97 +/- 0.1 (mean +/- SD) in control subjects, whereas LVIV/LVOV (1.87 +/- 0.88) was significantly higher in patients with VSD (p less than 0.01). In patients with VSD, LVIV/LVOV correlated with Qp/Qs determined invasively (y = 0.97, SEE = 0.23, n = 16). Thus with our method LVIV and COin can be accurately determined, and we suggest that Doppler-determined LVIV/LVOV is clinically useful for evaluating the shunt flow magnitude in VSD.

Noninvasive evaluation of the magnitude of aortic and mitral regurgitation by means of Doppler two-dimensional echocardiography

Using transmitral flow velocity and left ventricular ejection flow velocity, we measured left ventricular inflow volume (LVIV) and left ventricular outflow volume (LVOV) by pulsed Doppler echocardiography in 73 patients who had mitral valve regurgitation (MR), aortic valve regurgitation (AR), or no valvular regurgitation. Doppler-determined regurgitant volume (DOPRV), Doppler-determined regurgitant fraction (DOPRF), total stoke volume, and forward stroke volume were calculated to compare the severity assessed by angiographic scoring and the regurgitant fraction determined by radionuclide angiography (RIRF). In 17 patients with MR, LVIV (84.4 +/- 20.4 ml) was significantly greater (p less than 0.01) than LVOV (52.5 +/- 15.7 ml). LVOV, which is equivalent to forward stroke volume, was lower in patients with MR (52.2 +/- 15.7 ml) than in normal subjects (67.0 +/- 15.7 ml). In 15 patients with AR, LVOV (121.7 +/- 61.1 ml) was significantly greater (p less than 0.01) than LVIV (75.1 +/- 28.1 ml) and LVOV, which is equivalent to total stroke volume, was greater in patients with AR (121.7 +/- 61.1 ml) than in normal subjects (64.0 +/- 14.4 ml). DOPRF correlated with RIRF (r = 0.79, p less than 0.01, n = 11). DOPRV (mild: 10.5 +/- 8.5 ml; moderate: 28.8 +/- 13.6 ml; severe: 74.5 +/- 36.7 ml) and DOPRF (mild: 13.7% +/- 11.5%; moderate: 33.1% +/- 14.2%; severe: 52.6% +/- 15.3%) increased markedly with the severity of regurgitation as assessed by cineangiography. In AR, total stroke volume influenced both forward stroke volume and regurgitant volume, and in MR, regurgitant volume influenced both total stroke volume and forward stroke volume. Total stroke volume in AR and regurgitant volume in MR may play a key role in valvular regurgitation.

Effect of Colestimide on Reduction of Body Weight and Waist Circumference in Metabolic Syndrome Patients with Cardiovascular Risk Factors

Background and objective: Insulin resistance is thought to be central to the pathogenesis of abdominal obesity- linked metabolic syndrome (MetS). Colestimide, a 2-methylimidazole-epichlorohydrin polymer, is a new bile-acid- sequestering resin used to lower LDL cholesterol. In recent reports, bile acid-controlled signaling pathways have shown promise as novel drug targets to treat metabolic disorders, such as obesity, type 2 diabetes, hyperlipidemia, and athero- sclerosis. The aim of this study was to evaluate the efficacy of colestimide on weight loss in MetS patients. Methods: Sixty-one patients with MetS who had cardiovascular risk factors were randomized to receive lifestyle counsel- ing with or without colestimide treatment. The primary endpoint was achieved when the reduction in body weight is � 5%. Additionally, differences in the waist circumference and metabolic-associated profiles between the colestimide group and the control group, which received lifestyle modifications alone, were analyzed. Results: The numbers of participants who achieved � 5% weight loss significantly favored the colestimide group over the non-colestimide group (71.4% vs. 33.3%; p < 0.01). The mean reduction in waist circumference during the study period (average 22 weeks) was greater with colestimide than without it (10.1 � 5.4 vs. 7.1 � 5.2 cm, p < 0.05). Conclusions: The colestimide treatment together with lifestyle intervention was associated with reduction in body weight and waist circumference over a relatively short term in obese subjects. The combination of colestimide and lifestyle inter- vention may be useful for weight management in MetS patients with cardiovascular risk factors.

ENHANCEMENT OF EARLY DIASTOLIC FILLING PROVOKED BY DOBUTAMINE INFUSION IN DILATED CARDIOMYOPATHY

In considering whether to extend β-blocker therapy to dilated cardiomyopathy, we encountered a valuable case. A 40-year-old man with dilated cardiomyopathy developed heart failure with quite poor systolic function. After administration of β-blocker, his pump function improved. In echocardiographic monitoring before β-blocker therapy, only his early diastolic filling velocity was very responsive to dobutamine loading among functional parameters, including the systolic phase. This finding supports the hypothesis that the enhancement of left ventricular filling by dobutamine loading is a useful predictor in dilated cardiomyopathy patients of whether β-blocker will be effective or not.