To evaluate the relation between cardiac function and myocardial damage in patients with dilated cardiomyopathy (DCM), we compared echocardiographic parameters and histopathologic findings of the biopsied myocardium in 50 cases with DCM. As wall motion is much influenced by the increased afterload in cases with large ventricles, we generated a new contractile parameter, Force-Velocity Product (FVP). FVP was defined as the result obtained by multiplying mean circumferential fiber shortening velocity by noninvasive end-systolic wall stress. FVP correlated with percent fibrosis in the myocardium, which was reflected by no other echocardiographic parameter. We also evaluated the prognostic values of the echocardiographic and histopathologic parameters. FVP had the highest value among them. We conclude that FVP is a very useful clinical parameter, with the further advantage of being obtained noninvasively.

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We studied the effect of alpha human atrial natriuretic polypeptide (hANP) on venous vessels by occlusion plethysmography in 7 patients with congestive heart failure. In another 8 patients the effect of nitroglycerin was studied to validate the methodology. Forearm venous pressure (VP) and volume change (ΔV) were measured simultaneously. The relationship between venous pressure and volume change was described by the equation VP=C×e^(K×ΔV) (r=0.98±0.01) and the venous stiffness constant (K) was calculated. Alpha human atrial natriuretic polypeptide (0.1μM/kg/min) was infused intravenously at a dose sufficient to cause arteriodilation. The pressure-volume curve of the peripheral veins was shifted rightward on the volume axis and the stiffness constant (K) was decreased (-28.1%, p<0.03) significantly by nitroglycerin. Alpha human atrial natriuretic polypeptide significantly decreased systemic vascular resistance but did not shift the pressure-volume curve of the vein nor did it decrease the stiffness constant (K). We conclude that hANP has far less venodilating effect than arteriodilating effect in congestive heart failure patients.

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The diagnosis of ischemic heart disease by radionuclide ventriculography (RNV) is performed on the basis of an abnormal response of the left ventricular ejection fraction and the occurrence, or aggravation, of regional wall motion abnormality during exercise. However, the abnormal wall motion observed by RNV at rest is improved in some patients with coronary artery disease during exercise. We examined the clinical features of such patients who showed a paradoxical response of regional wall motion. The left ventricle was divided into 4 segments: anteroseptal, apical, inferior and posterolateral. The degree of wall motion of each segment was classified into 5 grades and scored according to a 5 point system: 4=normokinesis, 3=hypokinesis, 2=severe hypokinesis, 1=akinesis and 0=dyskinesis. The wall motion score (WMS) was calculated as the sum of each segment score. If the WMS increased by 2 points or more during exercise, the case was defined as having shown significant improvement of wall motion.
Improvement in WMS was found in 26 (12%) of 209 serial patients who underwent exercise RNV, exercise thallium myocardial scintigraphy and coronary angiography. Clinically, half of these patients had a variant form of angina pectoris. With respect to coronary lesions in the segments with reversible asynergy, 12 patients had 0 vessel disease, 8 had lesions with stenosis of less than 75% and 3 showed an adequate collateral circulation. Redistribution found on the exercise thallium myocardial scintigram at the same sites of improved wall motion was identified in only 1 patient. An analysis of patients with paradoxical improvement of wall motion during exercise suggests the involvement of coronary spasm, an improvement of coronary flow reserve, such as could be produced by regression or recanalization of the main lesions, or establishment of significant collateral circulation.

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Eight patients with atrial flutter (AF) and rapid atrial tachycardia (AT) (5 common AF, 1 uncommon AF and 2 AT) were treated with transesophageal atrial pacing (TEAP). In 5 patients no antiarrhythmic agent was used during this study, and in 3 patients procainamide was administrated intravenously.
Conversion to sinus rhythm was successfully achieved in 7 patients (5 common AF and 2 AT). Two patients were converted to sinus rhythm immediately after pacing, and transient atrial fibrillation was induced before conversion to sinus rhythm in 5 patients. TEAP failed to terminate the arrhythmia in 1 patient with uncommon AF.
Administration of procainamide reduced the atrial rate in 2 common AF and 1 AT, which were successfully converted to sinus rhythm by TEAP, but induced a rapid ventricular response in 2 patients, one of whom also developed hypotension before conversion. No significant complication due to TEAP was observed in this study.
In conclusion, TEAP is a noninvasive method with fewer complications and has nearly the same high efficacy for converting AF and rapid AT to sinus rhythm as DC cardioversion or transvenous atrial pacing.

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The properties of a class 1c antiarrhythmic drug, flecainide, were examined using 3 canine ventricular arrhythmia models: (1) digitalis-, (2) adrenaline- and (3) two-stage coronary ligation-induced arrhythmias. The minimum effective plasma concentration of flecainide was determined for each model. Flecainide suppressed the arrhythmias. The minimum effective plasma concentrations for arrhythmias induced by digitalis, adrenaline and 24 hr coronary ligation, were 0.9±0.2, 1.4±0.6, 1.5±0.4mcg/ml, respectively (mean±SD, n=6). These minimum effective plasma concentrations of flecainide were almost equal to the reported in vitro concentration that suppress the Na channels of isolated canine ventricular tissues. Thus, flecainide may suppress these arrhythmias by inhibiting the Na channels of cardiac cells.

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This study compared the hemodynamic effects of verapamil with other interventions that alter loading conditions in canines. The close correlation between peak filling velocity and systolic excursion indicated that peak filling velocity was dependent on systolic performance. However, verapamil caused a significantly greater increase in peak filling velocity than nitroprusside or volume loading despite a comparable increase in systolic excursion. Although both verapamil and volume loading induced increases in the peak filling velocity, the end-diastolic pressure and the peak pressure of the atrial v-wave, the pressure at the nadir of the atrial y-wave fell after verapamil but rose after volume loading. The rate of y-descent was also significantly greater after verapamil than after volume loading. These results indicate that, in addition to a reduction in afterload and an increase in preload, verapamil has a direct beneficial effect on ventricular filling.

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The cardiovascular effects of SIPI-549 [4'-methyl-7-(2-hydroxy-3-isopropylaminopropoxy)-flavone hydrochloride] were investigated in isolated canine atrial and ventricular muscles perfused with heparinized arterial blood from a donor dog. When SIPI-549 was administered intravenously to the intact donor dog, a slight hypotension was induced in a dose range of 0.01 to 3μmol/kg. At the same time, slight negative chronotropic and inotropic responses appeared in isolated and perfused atria, suggesting a cardiac depressant action.
Direct administration of SIPI-549 into the cannulated sinus node artery of the isolated atrium produced negative inotropic and biphasic chronotropic responses in a dose related manner (0.01-1μmol). SIPI-549 also induced a dose-dependent decrease in developed tension of the isolated left ventricle. The SIPI-549-induced negative chronotropic and inotropic effects were not modified by atropine in doses which blocked carbachol-induced negative chronotropic and inotropic effects. The SIPI-549-induced positive chronotropic effects were inhibited by propranolol but significantly potentiated by imipramine treatment, indicating that a large dose of SIPI-549 produces a release of catecholamine via a non-tyramine like action. Large doses of SIPI-549 did not significantly affect norepinephrine-induced positive chronotropic effects. These results indicate that SIPI-549 may have non-cholinergic cardiac depressant properties and no beta-adrenoceptor blocking activity. However, it appears to elicit a release of catecholamines in a non-tyramine-like manner at relatively large doses.

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A 45 year old man presented with the complaint of palpitations on swallowing. Clinical and radiological examination showed features of straight back syndrome and pectus excavatum. Electrocardiogram revealed supraventricular ectopics each time the patient swallowed. This illustrates a unique case of swallowing-related rhythm disturbance.

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Retinal artery embolism that had arisen as a complication of a left atrial myxoma was diagnosed in a young man who had suddenly developed a visual disorder in his left eye. A tumor in the left atrium was surgically excised. Pathologically, retinal embolism secondary to atrial myxoma is rare. To our knowledge, only 15 cases have been documented so far. The present case was only the second case of an isolated retinal embolism that had developed without systemic involvement, and the first case of retinal artery branch embolism that had resulted from a left atrial myxoma.

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Taurine showed a strong hypocholestrolemic effect in hypercholesterolemic WKY and SHRSP induced by the feeding of a high-fat and high-cholesterol diet. The hypocholesterolemic effect, which was more remarkable in SHRSP than in WKY, was mainly due to suppression of the marked increase of cholesterol, apo B and apo E in the VLDL and IDL fractions, and to prevention of cholesterol accumulation in the liver. In addition, a recovery in the HDL fraction of SHRSP, associated with increases of cholesterol and apo A-I, was observed after taurine treatment, while, in the HDL fraction of WKY, the decreased apo E content was reduced further and no effective change was observed.

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M-SHRSP, a rat strain considered as a suitable model for the study of juvenile human malignant hypertension, were subjected to a variety of treatments for hypertension. The results showed the following: 1) It should be possible, through suitable diets appropriately combined with the administration of a selection of anti-hypertensive agents involving different mechanisms, to develop marked preventive and therapeutic results even for extremely malignant hypertensive rats such as M-SHRSP. 2) SQ 29852 seems to be a better drug than captopril. 3) In malignant hypertension, factors other than the high blood pressure itself, also, seem to play a role in the occurrence of such vascular lesions as angionecrosis.

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Na loading accelerates urinary Ca excretion and this calciuretic effect of Na is possibly related to the aggravation of hypertension by Na loading in SHRSP. Our observation on Na-loaded SHRSP, so far indicated bones were more fragile, so that excess Na intake might be pathogenically involved in the development of osteoporosis. Therefore, Na-loaded SHRSP could be a good model for osteoporosis. On the other hand, Ca supplementation attenuated the development of severe hypertension and stroke in SHRSP. Since urinary Na excretion was increased in the group given the Casupplemented diet, the beneficial effect of Ca appeared to be ascribed to the acceleration of urinary Na excretion. Thus, it can be concluded under excess Na intake, enough Ca intake is important for the prevention not only of hypertensive diseases but also of osteoporosis.

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