Masaya Kino

Functional and histopathologic correlation in patients with dilated cardiomyopathy: An integrated evaluation by multivariate analysis

To correlate left ventricular function and histologic features in patients with dilated cardiomyopathy, precise indexes of hemodynamics and semiquantitative histologic data were combined for multivariate analysis. Right endomyocardial biopsy was performed at the time of cardiac catheterization. Five hemodynamic indexes were used for functional assessment: ejection fraction, ratio of end-systolic stress to volume index, end-diastolic stress, time constant (T) of left ventricular pressure fall, and end-systolic stress. Six histologic findings (disarray of myofibers, hypertrophy of myofibers, scarcity of myofibrils, nuclear changes of myofibers, vacuolization of myofibers and proliferation of collagen fibers) were graded from (-) to (4+). Each finding was assigned to category (-) or (+) according to the absence or presence of significant abnormality. Ordinary statistical analysis revealed that, although ejection fraction was lower in category (+) for proliferation of collagen fibers, ratio of end-systolic to volume index was reduced for category (+) of hypertrophy of myofibers. A significant correlation was present between hypertrophy of myofibers and proliferation of collagen fibers by Spearman rank correlation. When principal component analysis was applied to the hemodynamic data, two principal components could be extracted. Fishers discriminant analysis could clearly differentiate two categories (-) and (+) in the semiquantitative histologic finding of proliferation of collagen fibers. The analysis indicated that contractility was reduced with elevated afterload in that category (+). Thus, proliferation of collagen fibers may play a pivotal role in deteriorating contractility in patients with dilated cardiomyopathy.

Hypertrophic nonobstructive cardiomyopathy: A precise assessment of hemodynamic characteristics and clinical implications

A precise assessment of left ventricular function was performed in 20 patients with hypertrophic nonobstructive cardiomyopathy to elucidate the basic pathophysiology, and the data were compared with those in 22 normal subjects. Whereas end-diastolic pressure was high in those with cardiomyopathy, a more accurate index of preload, end-diastolic stress, did not differ from normal value. Afterload was about half the normal value. Both isovolumic indexes [peak positive dP/dt and (dP/dt)/DP40] and ejection phase indexes of contractility (ejection fraction) were in the normal range; however, the end-systolic stress volume ratio was significantly reduced (43% of the normal value). Although the left ventricular minute work index was in the normal range, the unit muscle performance (minute work/mass) was very low (49%). An abnormality of left ventricular relaxation was demonstrated by low peak negative dP/dt (56%) and prolonged time constant T (191%), and a stiff left ventricle was demonstrated by a high diastolic elastic stiffness constant (129%). These observations suggest that the contraction of a unit muscle is inappropriate to produce an adequate contraction of the whole ventricle, and that hypertrophy might be an adaptive process to maintain normal systolic function by increasing mass and reducing afterload.

Cardiovascular effects of a newly synthesized cardiotonic agent (TA-064) on normal and diseased hearts.

A new inotropic agent, TA-064, (-)-alpha-(3,4-dimethoxyphenethylaminomethyl)-4-hydroxybenzylalcohol, was shown to have strong effects in experimental animals. Its effectiveness and associated adverse effects were tested in humans invasively (n = 6) and noninvasively (n = 17). Increasing doses of intravenous infusion (1, 2, and 4 micrograms/kg/min) increased plasma levels to 15, 35, and 82 ng/ml, respectively, resulting in marked increases in the peak rate of left ventricular pressure rise (dP/dt) (1,450 +/- 63 to 3,042 +/- 349 mm Hg/s) (mean +/- standard error of the mean [SEM], p less than 0.01) and the ratio of dP/dt to left ventricular pressure at a developed pressure of 40 mm Hg (25 +/- 3 to 39 +/- 2 s-1) (p less than 0.01), with a reduction in left ventricular end-diastolic pressure (12 +/- 2 to 4 +/- 1 mm Hg) (p less than 0.01). Minimal or no changes were seen in heart rate and left ventricular systolic pressure. After a single oral dose (10 mg), the plasma level reached its peak at 90 minutes (16 +/- 9 ng/ml, n = 17). A positive inotropic effect was confirmed echocardiographically in both healthy volunteers (n = 8) and patients with congestive heart failure (CHF) (n = 9) who were maximally treated with conventional regimens: increase in mean velocity of circumferential fiber shortening (healthy volunteers: 1.29 +/- 0.05 to 1.60 +/- 0.11 circ/s [p less than 0.05]; patients with CHF: 0.69 +/- 0.08 to 0.93 +/- 0.09 circ/s [p less than 0.01]), ejection fraction (healthy volunteers: 68 +/- 2 to 75 +/- 2% [p less than 0.05], patients with CHF: 37 +/- 4 to 45 +/- 5% [p less than 0.01]) without change in heart rate. The cardiac index was increased only in the CHF group (2.71 +/- 0.22 to 3.21 +/- 0.24 liters/min/m2) (p less than 0.05). No significant untoward effects were observed. Thus TA-064 is a potent inotropic agent and can be used either parenterally or orally. Salutary effects can be expected in patients with congestive heart failure who are treated with digitalis and diuretic agents.

Chronic effects of ethanol under partial inhibition of catalase activity in the rat heart: Light and electron microscopic observations☆

In order to test the hypothesis that cardiac catalase plays a protective role in the pathogenesis of alcoholic cardiomyopathy, ethanol, comprising 36% of dietary calories, was administered to the rats for 5 weeks under inhibited cardiac catalase activity. Rats were treated with 3-amino-1,2,4-triazole (AT), a specific enzyme inhibitor, or iso-osmotic saline as control. During ethanol feeding, cardiac catalase activity was significantly inhibited at 24 h after AT, 25.6 ± 4.7 IU/mg protein, compared to rats given isoosmotic saline, 51.0 ± 9.1 IU/mg protein (s.d.m.) (P < 0.001). Under light microscopy, observed were intrasarcoplasmic vacuolization and occasional foci of necrosis and fibrosis. Ultrastructural abnormalities included very extensive vesicular changes in the myocardial cells, abnormally increased interstitial fibrosis, dilatation of tubular structures of sarcoplasmic reticulum, increased numbers of lysosomes, dehiscence of intercalated disc and various mitochondrial alterations including amorphous inclusion body. None of the rats given ethanol + saline, pair-fed diet + AT or saline showed comparable changes. Thus, cardiac catalase is considered to play a metabolic and protective role in the rat myocardium chronically exposed to ethanol.

Mechanisms of compensation and decompensation in dilated cardiomyopathy

Left ventricular (LV) function was evaluated in 32 patients with dilated cardiomyopathy (DC) who underwent cardiac catheterization during the past 6 years (group 4), and the results were compared with the data of 30 normal subjects (group 1). The patients were divided into mildly (group 2, 12 patients) and severely symptomatic subgroups (group 3, 20 patients). DC was characterized by dilated and poorly contracting left ventricle with increased muscle mass, reduced cardiac output and elevated systemic vascular resistance. LV volume was larger, ejection fraction was lower, and end-diastolic and end-systolic stresses were higher in group 3 than in groups 1 and 2. No significant differences were seen in LV muscle mass and wall thickness between groups 2 and 3. A significant inverse correlation was seen between ejection fraction and end-systolic stress in patients with DC (Y = -0.05x + 48.7, r = 0.57, p less than 0.01). The slope of the correlation line between end-systolic stress and volume in DC (Y = 1.20x + 135, r = 0.52, p less than 0.02) was less steep than that of normal subjects (Y = 3.68x + 40, r = 0.64, p less than 0.001). These observations indicate that the primary problem of DC is depressed contractility.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiorenal effects of an orally active dopamine prodrug (TA-870) in patients with congestive heart failure.

The effects of TA-870, a newly synthesized orally active dopamine prodrug, on the cardiorenal functions were investigated in 12 patients with severe chronic congestive heart failure. A single oral dose of TA-870 (1,200 mg) improved left ventricular fractional shortening and mean circumferential velocity on M-mode echocardiography (p < 0.01 for both). Renal plasma flow and glomerular filtration rate improved with TA-870 (p < 0.01 and p < 0.05, respectively); urine volume and sodium excretion increased (p < 0.01 for both). Blood pressure and heart rate did not change during the 4-h experimental period. Mean plasma free dopamine levels peaked 1 h after dosing. These data suggest that the cardiorenal effects of oral TA-870 are comparable with those of continuous intravenous injection of dopamine. Thus, TA-870 appears to be a useful alternative drug to intravenous dopamine.

Electron-microscopic and immunohistochemical studies on endomyocardial biopsies from a patient with eosinophilic endomyocardial disease.

SummaryLight- and electron-microscopic studies and immunohistochemical procedures were carried out on blood eosinophils and left ventricular endomyocardial biopsies from a 68-year-old man with an eosinophilia of 8.2 × 109/l and congestive cardiac failure due to eosinophilic endomyocardial disease. Some blood eosinophils were vacuolated and degranulated, and reversal of the normal staining pattern of eosinophil granules was seen by means of electron microscopy. The biopsies showed degenerative changes in the cardiac myocytes, with interstitial fibrosis and infiltration by numerous eosinophils, mast cells, and macrophages. Eosinophils infiltrating the myocardium showed a decrease in the number of granules, many of which were indistinct or contained dissolving crystalloids, which occasionally were seen to be discharged onto the surface of adjacent cardiac myocytes. Immunohistochemical studies of the endomyocardial biopsies with a monoclonal antibody, which is specific for activated eosinophils and binds to the secreted forms of eosinophil cationic protein (ECP) and eosinophil protein-X (EP-X), demonstrated that the lesions contained numerous activated eosinophils and secreted ECP and EP-X. These findings support the concept that in eosinophilic endomyocardial disease, activated eosinophils infiltrate and degranulate in the myocardium, releasing eosinophil cationic proteins which then damage adjacent myocardial cells.

Genetic linkage analyses of Romano-Ward syndrome (RWS) in 13 Japanese families

Romano-Ward syndrome (RWS) is an autosomal dominant disorder characterized by prolongation of the electrocardiographic QT interval, with clinical manifestations that include recurrent syncope and sudden death from ventricular arrhythmias. Presymptomatic diagnosis is difficult because of the variability in these signs among carriers, but it is important for clinical management to prevent sudden cardiac death. To find an LQT (long QT) locus in Japanese patients and to identify DNA markers useful for presymptomatic diagnosis, linkage analyses were undertaken in 13 Japanese families with RWS patients by means of two DNA markers located on 11p15.5. One of these marker loci, HRAS, was previously reported to be tightly linked to the LQT locus in another ethnic group. Our analyses of homogeneity suggest evidence for genetic heterogeneity of RWS within the Japanese population.

The Association between Cerebral White Matter Lesions and Plasma Omega-3 to Omega-6 Polyunsaturated Fatty Acids Ratio to Cognitive Impairment Development

Objective. Cerebral white matter hyperintensity (WMH) with magnetic resonance imaging (MRI) has a potential for predicting cognitive impairment. Serum polyunsaturated fatty acid (PUFA) levels are important for evaluating the extent of atherosclerosis. We investigated whether abnormal PUFA levels affected WMH grading and cognitive function in patients without significant cognitive impairment. Methods. Atherosclerotic risk factors, the internal carotid artery (ICA) plaque, and serum ratios of eicosapentaenoic to arachidonic acids (EPA/AA) and docosahexaenoic to arachidonic acids (DHA/AA) were assessed in 286 patients. The relationship among these risk factors, WMH, and cognitive function was evaluated using WMH grading and the Mini-Mental State Examination (MMSE). Results. The development of WMH was associated with aging, hypertension, ICA plaques, and a low serum EPA/AA ratio (<0.38, obtained as the median value) but was not related to dyslipidemia, diabetes, smoking, and a low serum DHA/AA ratio (<0.84, obtained as the median value). In addition, the MMSE score deteriorated slightly with the progression of WMH (29.7 ± 1.0 compared to 28.4 ± 2.1, P < 0.0001). Conclusions. The progression of WMH was associated with a low serum EPA/AA ratio and accompanied minimal deterioration in cognitive function. Sufficient omega-3 PUFA intake may be effective in preventing the development of cognitive impairment.

Factors discriminating survivors and nonsurvivors in alcoholic heart disease

SummaryEighteen patients with dilated cardiomyopathy and a history of excessive ethanol intake were monitored for 3–98 months (mean 23 months). Six patients died (mean age 43.7±9.2 years) and 12 patients survived (mean age 48.8±9.5 years). Of the echocardiographic findings taken during heart failure, only the relative wall thickness to the internal dimension of the left ventricle (t/r ratio) differed significantly (survivors 0.33±0.77 vs. nonsurvivors 0.25±0.04,P<0.05). Of the hemodynamic data obtained after treatment of heart failure, left ventricular end-diastolic pressure differed significantly (survivors 6±2 vs. nonsurvivors 12±4 mmHg,P<0.001). The two groups could not be differentiated by ejection fraction, cardiac output, end-diastolic or end-systolic volumes, or semi-quantative analysis of histologic findings obtained by right ventricular endomyocardial biopsy (light microscopy). Only two of six nonsurvivors (33%) succeeded in abstaining from alcohol, while eight of twelve survivors (67%) became teetotalers (P<0.05). Total abstinence from alcohol seems to be essential but was not necessarily followed by recovery in the most severe cases. Thus, the absence of adequate hypertrophy and high left ventricular filling pressure may predict the prognosis in alcoholic heart disease.