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Timely indication of surgical correction of aortic regurgitation (AR) depends on precise evaluation of left ventricular (LV) function. However, it may still be difficult to accurately predict surgical outcome with only currently available indexes of LV function. We undertook this study to obtain a novel index of LV function from altered LV fluid dynamics in patients with AR. AR flow is expected to cause definitive changes in intraventricular flow distributions. The degree of such changes may be mainly determined by the severity of regurgitation but variously affected by chamber size, diastolic property and filling pressure of the left ventricle. Therefore, our hypothesis is that the changes in the intraventricular fluid dynamics reflect LV function in patients with similar degrees of AR. We tested this hypothesis in patients with severe AR using the Doppler ultrasound technique and obtained a novel index for estimating LV function.

The chemical structure and the properties of the products of the reaction of poly(vinyl chloride) (PVC) with ethylenediamine hydrotrisulphide were investigated. PVC derivatives containing a polysulphide crosslinkage and a hydropolysulphide pendant (PSC-PVC) were obtained by the reaction of PVC with ethylenediamine hydrotrisulphide in ethylenediamine (EN) as well as in EN-diglyme, and EN-benzene at 20–50°C for 0.5–5h. The chemical structure of PSC-PVC was determined from crosslinking density before and after iodine oxidation and elemental analysis. Scission of polysulphide crosslinkage in PSC-PVC by some thiols was carried out in tetrahydrofuran-triethylamine solution at 30°C for 1–4h as well as in a hot roller mill at 125–180°C for 2–8 min. The former product was photocrosslinked under ultra-violet irradiation in air and the latter showed the properties of a plastic, a leather, and a rubber with increasing weight of dioctyl phthalate.

We performed rhythm conversion on 33 euthyroid patients with post-thyrotoxic atrial fibrillation who do not revert spontaneously to sinus rhythm from atrial fibrillation. The duration of atrial fibrillation ranged from 9 to 59 months (mean 25 ± 14). The protocol of rhythm conversion was to first attempt pharmacological conversion with disopyramide and then to perform electrical cardioversion on the non-converters. Of 33 patients, 25 were converted to sinus rhythm (6 by disopyramide and 19 by electrical cardioversion), resulting in 8 non-converters. However, it was later discovered that cardioversion had been applied to 4 of the 8 non-converters when these patients had had a recurrence of thyrotoxicosis. These 4 patients were subjected to a second electrical cardioversion after attaining the euthyroid state. Sinus rhythm was restored in all 4 patients, giving a cardioversion rate of 88%. The sinus rhythm was maintained in 25 of the total 29 converters (86%) at the time of follow-up (10–68 months, mean 35 ± 19 months). Our studies suggest that cardioversion should be encouraged for thyrotoxic atrial fibrillation, even if the duration of atrial fibrillation is long-standing, since there is excellent maintenance of sinus rhythm and even delayed application of cardioversion may improve its success rate.

A patient with malignant lymphoma who developed congestive heart failure, conduction disturbances and myocardial infarction is presented. Two-dimensional echocardiography revealed marked thickening of the left ventricular wall, where the gallium scan correspondingly showed an abnormal accumulation. Irradiation to the mediastinum resulted in a dramatic decrease in ventricular wall thickness and disappearance of the gallium accumulation. Postmortem examination confirmed previous lymphomatous involvement of the myocardium. Combined techniques, including echocardiography and gallium scan, can be valuable for noninvasive detection and follow-up of myocardial involvement in patients with malignant lymphoma.

Polypyrrole/PEOLiClO 4 junctions were prepared in situ by the electrochemical polymerization of pyrrole in the polymer electrolyte PEOLiClO 4 . The junction prepared in situ by the potential sweep method exhibited rectifying behavior in the current-voltage curves. The capacitance-voltage properties of the junction showed an energy barrier at the interface between polypyrrole and PEOLiClO 4 . On the contrary, polypyrrole/PEOLiClO 4 junctions prepared in situ by galvanostatic and potentiostatic methods did not show rectifying behavior. These results are explained on the basis of the properties of the interface between p-type polypyrrole and the polymer electrolyte.

Myocardial protective effects of intracoronary administration of relatively small doses of propranolol were examined and compared with systemic administration in 20 open-chest dogs. In group 1 (n = 6) rate-pressure-product (R X P) did not change during 5-minute left anterior descending artery (LAD) perfusion with deoxygenated Krebs-Henseleit solutions (KHS). However, R X P decreased by the same degree in group 2 (n = 7), which received perfusion with KHS containing 0.4 or 0.8 mg/dl of propranolol, and in group 3 (n = 7) given LAD perfusion with original KHS and systemic administration of 0.02 to 0.04 mg/kg of propranolol. Total administered doses of propranolol were the same for groups 2 and 3. Transmural biopsy after 5 minutes of perfusion revealed less severe metabolic deterioration of hypoxic myocardium in group 2 when compared with that in group 1, as evidenced by higher ATP (adenosine triphosphate) (2.81 +/- 0.35 versus 2.23 +/- 0.45 mumol/g, p less than 0.05) and lower lactate content (5.62 +/- 1.44 versus 9.01 +/- 2.62 mumol/g, p less than 0.05). On the other hand, significant metabolic preservation was not noted in group 3. Sequential changes in regional myocardial contraction did not differ among the three groups. In conclusion, intracoronary administration of propranolol showed myocardial protective effects that were not mediated by the changes in hemodynamics and myocardial contraction.

A new sampling method of cross-sectioning the canine heart in situ was developed. A mechanical device, driven by spring power, enabled cross-sectioning of a short-axis plane of the beating canine heart (4 mm thick) with high speed rotating blades, at a pre-determined phase of the cardiac cycle, and instantaneous freeze-clamping (2.4 mm thick) with pre-cooled aluminum blocks, all within 120 ms. By this method, the anatomical structures of the sample were well preserved. Transmural metabolism and flow distribution were instantaneously fixed and high resolution of the two-dimensional redox state was obtained by application of NADH fluorescence photography. Micro-samplings from the desired portion of the cross-sectional slice were possible at −190°C. NADH fluorescence of the samples did not increase from the surface to 1.2 mm in depth, confirming that there was no ischemic artifact. With the present technique, a heart sample in which transmural metabolism, and the redox state, are fixed and visualized is attainable, thus providing a new tool for the study of myocardial ischemia.