BACKGROUND: Abnormalities of the left ventricular diastolic function can be classified by pulsed Doppler echocardiography, but sometimes it may be difficult to differentiate normal diastolic function from pseudonormalization. Heart failure caused by increased left ventricular filling pressure is rather associated with pseudonormalization or restrictive pattern than normal pattem or relaxation abnormality. We investigated the usefulness of color M-mode Doppler echocardiographic indexes in differentiating normal relaxation from pseudonormalization after acute myocardial infarction. METHOD: Echocardiographic examination including color M-mode Doppler was performed in 44 patients with acute myocardial infarction between 10 and 14 days after attack. 34 patients without in-hospital congestive heart failure(CHF) were assigned as group I, and 10 patients with in-hospital CHF as group II. Flow propagation slope(FPS), time difference(TD) between the occurrence of peak flow velocity in the apical region and at the mitral tip, and normalized time difference(nTD) by mitral and apical distance were measured with color M-mode Doppler echocardiography. RESULTS: FPS was lower in group II(group I, 42.0+/-20.6cm/sec vs group II, 27.8+/-8.0cm/ sec , p=0.065). Both groups had similar TD and nTD. FPS was compared in patients with E/ A ratio of mitral inflow greater than 1(22 patients of group I and 7 patients of group II). Patients with E/A) 1 in group II had significantly lower FPS(group I, 52.1+/-17.5cm/sec vs group II, 31.0+/-7.4cm/sec ; p(0.01). CONCLUSION: FPS was significantly decreased after acute myocardial infarction in patients with in-hospital CHF compared with patients without in-hospital CHF, even when E/A ratio of mitral inflow was greater than 1. Therefore, FPS was an useful index in differentiating normal relaxation from pseudonormalization.
Echocardiography ; Echocardiography, Doppler* ; Echocardiography, Doppler, Pulsed ; Estrogens, Conjugated (USP)* ; Heart ; Heart Failure* ; Humans ; Myocardial Infarction* ; Relaxation

PURPOSE: To assess the usefulness of diffusion-weighted imaging(DWI) in evaluating serial parenchymal changesin renal infarction induced by renal artery ligation, by comparing this with the conventional spin echo techniqueand correlating the results with the histopathological findings. MATERIALS AND METHODS: In 22 rabbits, renalinfarction was induced by ligation of the renal artery. Spin-echo T1-weighted imaging(T1WI), turbo spin-echo(TSE)T2-weighted imaging(T2WI), and DWI were performed, using a 1.5-T superconductive unit, at 30 minutes, 1 hour, 2,3, 6, 12 and 24 hours, and 2, 3, 7 and 20 days after left renal artery ligation. Changes in signal intensity onT1WI, T2WI, and DWI were correlated with histopathologic findings. RESULTS: On MR images obtained 30 minutesafter ligation, the signal intensity of affected kidney was not significantly different from that of contralateralkidney, as seen on T1WI and T2WI, but was noticeably higher on DWI. On T2WI, the signal intensity ratio(SIR) wasslightly higher over time from 30 minutes to 2 days after ligation, and then decreased slightly. The SIR on DWIincreased abruptly at 30 minutes, remained high until 12 hours, and then fell, returning to close to the normalrange at between 2 and 3 days. It fell further, below the normal range, until 20 days after ligation. The mainhistopathologic findings after ligation were congestion and swelling of renal tubules (1-6 hours after ligation),degeneration and necrosis of renal tubules (12 hours - 2 days), coagulation necrosis of renal tubules(3 days),collection of cellular debris between renal tubules (7 days), and proliferation of fibroblast between renaltubules (20 days). CONCLUSION: Diffusion-weighted imaging is useful for the detection of hyperacute renalinfarction, and the apparent diffusion coefficient may provide additional information concerning its evolution.
Animals ; Diffusion ; Estrogens, Conjugated (USP) ; Fibroblasts ; Infarction* ; Kidney ; Ligation* ; Magnetic Resonance Imaging* ; Necrosis ; Rabbits* ; Reference Values ; Renal Artery*