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In 103 hearts with various forms of cardiac muscle hypertrophy the following parameters were estimated: diameter, length, volume, density and number of myocytes, as well as the density of nuclei of myocytes. The values of all histometric parameters correlated well with the LV weight up to 350 g. In heavier hearts these parameters were approximately at the same magnitude. The number of myocytes was significantly higher in hearts with LV weight above 250 g than in hearts below 250 g: 5.53 x 10(9) vs 4.31 x 10(9), p less than 0.001. The influence of coronary artery diameters, degree of atherosclerosis, weight and percent of fibrous tissue and age on LV weight were evaluated as well. Only coronary artery diameters significantly influenced on LV weight. On the basis of linear discriminant function, three classes of hearts were separated: 1) LV weight 250 g - absence of hyperplasia, only hypertrophy 2) LV weight 251-350 g - hypertrophy + signs of hyperplasia 3) LV weight 350 g - marked signs of hyperplasia Among 18 patients with the LV weight above 350 g (all patients with congestive heart failure), 11 suffered from valvular disease, 3 were postinfarction patients, 2 suffered from primary hypertension and 2 from primary congestive cardiomyopathy. It indicates that, irrespective to the etiologic factor, hyperplasia is a simple result of the cardiac muscle mass increase.
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PMID:[Myocardial structure in various forms of hypertrophy. II. Myocyte hypertrophy or hyperplasia? Results of the study]. 215 Jun 80

Careful consideration of all relevant scientific evidence and a critical assessment of data quality show that thiazide diuretics are not cardiotoxic. Of 12 reported trials only two recorded more coronary heart disease events in thiazide-treated patients than in controls. One of these two was a subgroup of a larger study (Heart Attack Prevention in Primary Hypertension, HAPPHY) which found no difference between thiazide-treated and beta-blocker-treated patients. The other, the Oslo study, was too small to allow valid conclusions. Results from a subgroup in the Multiple Risk Factor Intervention Trial (MRFIT) that appeared to supply evidence for thiazide-related cardiotoxicity are suspect when examined critically. Further evidence from 24- to 28-h ECG monitoring does not support the hypothesis that thiazide diuretics, either in the presence or absence of hypokalemia, increase the frequency or severity of ventricular arrhythmias. Reports of a thiazide-induced intracellular magnesium deficiency as a cause of ventricular arrhythmias have also not been confirmed; the development of arrhythmias in acute myocardial infarction appears to be due to an increase in catecholamine levels rather than hypokalemia. There appears to be little evidence to support the assumption that long-term use of thiazide diuretics aggravates or accelerates atherosclerosis of the coronary arteries; any fall in serum cholesterol appears to be transient. For the great majority of patients with uncomplicated hypertension, without a previous myocardial infarction, congestive heart failure, diabetes mellitus or gout, thiazide diuretics appear to be both safe and effective antihypertensive agents.
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PMID:The cardiotoxicity of thiazide diuretics: review of the evidence. 221 84

The purpose of this article was to review the clinical and experimental features of diabetic cardiomyopathy, with particular relevance to the Black population. One hundred thirty-seven studies were identified, of which 57 were selected as references for this article. Diabetes is associated with the development of cardiomyopathy, independent of coronary atherosclerosis. Pathological studies show myocardial hypertrophy and fibrosis; microvascular pathology is also present, but all of these pathological findings have an uncertain relationship to myocardial failure. Hemodynamic findings of both congestive and restrictive cardiomyopathy have been described. Noninvasive studies revealed abnormal systolic and diastolic function in many diabetic subjects, particularly in the presence of diabetic complications and/or hypertension. Experimental studies have focused on the mildly diabetic dog and the severely diabetic rat. One year of diabetes in dogs resulted in decreased left ventricular compliance and increased interstitial connective tissue. Studies in the diabetic rat showed a marked slowing of contraction and relaxation. Chronic insulin therapy reversed the changes in the rat model. Combining hypertension with diabetes in the rat resulted in increased myocardial and coronary microvascular pathology and greater changes in isolated muscle function, electrophysiology, and contractile protein biochemistry. Many hypertensive diabetic rats died spontaneously, showing signs of congestive heart failure. Diabetic cardiomyopathy is a significant cause of heart failure in diabetic subjects and occurs more frequently in those with microvascular complications and/or hypertension. Clinical studies are needed to clarify the natural history of this disorder, focusing on the benefits of tight control of hyperglycemia and treatment of associated hypertension. Experimental studies will clarify the pathophysiology and contribute to improved therapy. The high prevalence of diabetes and hypertension in Blacks makes these considerations especially relevant to this population.
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PMID:Diabetic cardiomyopathy. 226 38

The manifestations of cardiac involvement in hypertension include: (1) the development of hypertensive heart disease characterized by left ventricular hypertrophy (LVH), and (2) the consequences of coronary atherosclerosis, as angina pectoris, myocardial infarction, and sudden cardiac death. Whereas the former is directly related to increased blood pressure, the latter are sequelae of atherosclerosis per se, and hypertension acts only as a risk factor in this regard. This can partially explain why antihypertensive treatment is effective in diminishing the incidence of congestive heart failure, which is the final consequence of LVH, but is not very effective in preventing coronary complications. It is generally accepted about LVH that increased arterial pressure is the major stimulus to cardiac hypertrophy in hypertension; however, there are a lot of both quantitative and qualitative events suggesting that other factors beside blood pressure levels can modulate the development of LVH, in particular neurohumoral influences. From a morphological point of view, hypertrophy of the cardiac muscle is defined as an increase in the size of existing myocardial fibers. In most experimental models, myocardial hypertrophy is associated with myosin isoenzymatic changes, consisting in a shift from the faster migrating isoenzyme V1 to V3, a form that migrates more slowly. However these changes do not occur in all animal species and particularly in humans. In the hypertrophied human ventricle, a decreased ATPase activity of myofibrils was observed, probably related to changes in myosin light chains. Presently the changes in ATPase activity and in ventricular contractility do not still have a clear molecular basis in humans.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Heart and hypertension. 252 4

Cardiovascular manifestations develop in the majority of SLE patients at some time during the course of their illness, the most common being acute fibrinous pericarditis and pericardial effusion. Echocardiography has demonstrated an increased incidence of pericardial effusion, even in those who have minimal symptoms. Chronic adhesive pericarditis, pericardial tamponade, and constrictive pericarditis occur rarely. While myocarditis is commonly noted at autopsy, it is often silent clinically. Diagnosis during life can be confirmed only by endomyocardial biopsy. Electrocardiographic changes are often nonspecific. Endocarditis with superimposed nonbacterial verrucous vegetations (Libman-Sacks) is noted in more than 40% of hearts at autopsy, but is rarely diagnosed during life. Valve dysfunctions, such as aortic stenosis, aortic insufficiency, mitral stenosis, and mitral insufficiency, occasionally manifest during life and rarely may necessitate surgery. Atrial and ventricular arrhythmias, first degree AV block, and acquired CHB occur in association with pericarditis, myocarditis, vasculitis, and myocardial fibrosis, respectively. CCHB developing in newborns of mothers with SLE, particularly those who have an antibody to soluble tissue ribonuclear protein RO(SS-A), is increasingly being appreciated by both pediatric cardiologists and rheumatologists. Recently, severe coronary atherosclerosis resulting in angina pectoris and/or myocardial infarction in young adults has been noted, particularly in those who had developed risk factors such as hypertension and hyperlipidemia while receiving prolonged corticosteroid therapy. Rarely, coronary arteritis may produce similar symptoms. Congestive heart failure of either single or multiple etiologies carries an ominous prognosis. It remains a cause of high morbidity and mortality unless recognized early and treated properly. Extracardiac vascular manifestations of SLE include telangiectasia, vasculitis, livedo reticularis, Raynaud's phenomena, and thrombophlebitis, all of which may occur either alone or in different combinations. Evidence is now slowly accumulating that substantiates that immune complex deposition, complement activation and subsequent inflammatory reaction is responsible for the majority of the cardiovascular manifestations of SLE, for example, pericarditis, myocarditis, endocarditis, coronary arteritis, coronary atherosclerosis, and systemic and pulmonary vasculitis.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Cardiovascular manifestations of systemic lupus erythematosus: current perspective. 286 Jun 99

More than half of the United States population over 65 years of age has essential hypertension. In 1984, there were 10 million elderly hypertensive persons and this number will reach 25 million in the near future. These patients are at high risk for congestive heart failure, stroke, heart attack, and dissecting aneurysm. Successful reduction of blood pressure can lower these risks considerably, but rational treatment depends on understanding the complex pathophysiology of hypertension in older patients. In fact, treatment that does not take into account the combined effects of aging and hypertension on the cardiovascular system and the kidneys may do more harm than the hypertension itself. Among the prominent age-related cardiovascular changes are stiffening of the arterial tree, with or without a contribution from atherosclerosis. This reduces arterial compliance and increases afterload, resulting in the left-ventricular hypertrophy seen in old age and leading to a progressive rise in systolic pressure. There is considerable shrinkage of the kidneys, due primarily to loss of glomerular and tubular tissue in the cortex, along with sclerosis of the glomeruli and formation of tubular diverticula. Arteriolar changes lead to reduced renal blood flow, the shunting of blood around the glomeruli, and thus a reduction in glomerular filtration rate. Renal water and electrolyte excretion are changed, making homeostasis more difficult to maintain, and the renin-angiotensin system is altered, helping to blunt the kidneys' response to pressure changes. Essential hypertension superimposed on all the foregoing effects exacerbates them. Peripheral resistance is usually markedly elevated in older hypertensive persons, which increases afterload directly.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Pathophysiology of hypertension in older patients. 304 95

Cardiac transplantation for the treatment of end-stage congestive heart failure has been shown to be of benefit regardless of the etiology. With few exceptions, the evaluation of patients with end-stage heart failure is the same, regardless of the etiology. In those with cardiomyopathy not as a result of CAD, special attention must be given to exclude secondary causes of cardiomyopathy such as amyloidosis, hemochromatosis, and sarcoidosis, as well as generalized systemic illnesses that may also involve the heart, either secondary or hereditary, because special consideration must be given to these patients on a case-by-case basis to determine that there is no general systemic involvement of the illness that would preclude satisfactory rehabilitation after transplantation. Before cardiac transplantation becomes widely available, there must be a greater number of donor hearts, the lack of which now severely limits the number of transplants performed in comparison with the estimated need.66 Additionally, more effective and specific immunosuppressive agents must be identified in order to reduce the incidence of rejection, infection, and accelerated atherosclerosis that now limits the longevity of transplant recipients. Furthermore, the ideal immunosuppressive agent should be associated with fewer side effects than those currently available. The emotional and economic burdens placed on the patient, the family, and society must be balanced against the benefits generated by the procedure. Despite these limitations, cardiac transplantation continues to offer hope for the terminally ill patient, which must be tempered by an understanding of the real limitations of transplantation.
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PMID:Patient selection and results of cardiac transplantation in patients with cardiomyopathy. 304 84

The major antihypertensive mechanism of calcium antagonists is by decreasing the systemic vascular resistance, modified by the counter-regulatory responses of the baroreflexes and the renin-angiotensin-aldosterone system. In severe hypertension, the concept that calcium overload of the vascular myocyte could precipitate or aggravate peripheral vasoconstriction provides a logical basis for the use of these agents as first choice therapy; nifedipine, especially, has been well tested. As monotherapy for mild to moderate hypertension each of the three first-generation agents compares well with beta-blockers. Calcium antagonists may have a special role in the therapy of certain patient groups (elderly, black) or in those subjects whose life style involves intense physical or mental exertion (hemodynamics better maintained than with beta-blockade) or in patients with early end-organ damage such as left ventricular hypertrophy or renal insufficiency. However, the goal blood pressure may not be reached during monotherapy so that drug combinations may be required. Further indications for these compounds are as follows. Verapamil and diltiazem are frequently used in supraventricular tachycardias including acute and chronic atrial fibrillation. In the arrhythmias of the Wolff-Parkinson-White syndrome, there is the potential danger of provocation of anterograde conduction. Further indications for calcium antagonists, still under evaluation, include congestive heart failure (controversial), hypertrophic cardiomyopathy (verapamil), primary pulmonary hypertension (high doses required), Raynaud's phenomenon (nifedipine and diltiazem effective), peripheral vascular disease (proof not yet documented), cerebral insufficiency and subarachnoid hemorrhage (nimodipine promising), migraine, exertional bronchospasm, renal disease, atherosclerosis (experimental), and primary aldosteronism (nifedipine inhibits aldosterone release). Second-generation agents include dihydropyridines, such as nitrendipine, nicardipine, felodipine, amlodipine, nisoldipine, nimodipine, and isradipine. From these will be selected agents that are longer acting and provide higher vascular selectivity. New preparations of existing agents include slow-release formulations of nifedipine, verapamil, and diltiazem. Minor side effects include those caused by vasodilation (flushing and headaches), constipation (verapamil), and ankle edema. Serious side effects are rare and result from improper use of these agents, as when intravenous verapamil is given to patients with sinus or atrioventricular nodal depression from drugs or disease, or nifedipine to patients with aortic stenosis. The potential of a marked negative inotropic effect is usually offset by afterload reduction, especially in the case of nifedipine. Yet caution is required when calcium antagonists, especially verapamil, are given to patients with myocardial failure unless caused by hypertensive heart disease. Drug interactions of calcium antagonists occur with other cardiovascular agents such as alpha-adrenergic blockers, beta-adrenergic blockers, digoxin, quinidine, and disopyramide.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Calcium channel antagonists. Part III: Use and comparative efficacy in hypertension and supraventricular arrhythmias. Minor indications. 315 29

Congestive heart failure (CHF) evolves either from an excessive workload or in response to loss of myocardium, both of which cause cardiac hypertrophy, increased cardiac pressure, and loss of functional reserve. Nearly 60% of patients in heart failure present with ischemic cardiomyopathy, which in its chronic form exhibits biventricular dilatation, elevated left ventricular mass, and extensive large-vessel atherosclerosis. The hypertrophy is proportional to the loss of myocardium, although animal studies suggest this varies with the infarct size. However, recent studies indicate that early afterload reduction may relieve the hypertrophic stimulus and prevent degeneration. Some 30% to 40% of patients in heart failure present with an idiopathic dilated cardiomyopathy, with a patchy but diffuse loss of tissue on microscopy, reactive hypertrophy in the surviving cells, and interstitial fibrosis and replacement scarring. The ultrastructural changes still await clarification. The role of pharmacologic intervention still remains unclear. However, any reduction in mortality will necessitate the identification of those cellular changes that inevitably lead to secondary degeneration of the remaining viable myocardium.
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PMID:The pathophysiologic profile of congestive heart failure. 315 47

Acromegaly involves cardiovascular complications mostly due to the presence of hypertension, diabetes and atherosclerosis. However the appearance of cardiac decompensation and arrhythmias in the absence of predisposing factors tends to support the hypothesis of a specific myocardiopathy caused by excess GH. In order to assess the existence and course of subclinical cardiac alterations, 8 acromegaly patients were examined: 4 males and 4 females aged 31-56 with GH levels of 24-70 ng/ml (M + CD X 47 +/- 16) and no cardiovascular symptoms. One of the patients had moderate hypertension and 2 reduced glucose tolerance. The basal ECG showed sporadic ventricular extrasystoles in 2 cases and alterations compatible with left ventricular hypertrophy in another, while the effort ECG produced an asymptomatic depression of the ST segment in the hypertensive patient. The chest X-ray was normal in all cases. The echocardiography study investigated: the thickness of the interventricular septum (IVS = 13.9 +/- 2.8 mm), the thickness of the posterior wall of the left ventricle (LPW = 10.6 +/- 2.9 mm), the septum/posterior wall ratio (IVS/LPW = 1.3 +/- 0.2 the diastolic diameter (DD = 15.4 +/- 11.4 mm), the fraction of shortening (FS = 39.1 +/- 14.5%), the ejection fraction (EF = 64.1 +/- 18.4%) and revealed asymmetrical septal hypertrophy in 3 cases, concentric hypertrophy in another two. In two cases the DD and EF were distinctly altered. The patients were re-examined 2-4 years after surgical or radiation treatment. GH levels (M +/- SD = 10.3 +/- 10.1 ng/ml) were normal in 4 cases and still high, though lower in another two. The remaining two patients had borderline GH levels with high Sm-C. The ECG and chest X-ray were unchanged while echocardiography revealed a significant deterioration in heart function as far as DD (56.4 +/- 10.8 mm, p less than 0.05) were concerned with frankly pathological results in 4 and 3 cases respectively. These data confirm the view that most acromegalic patients present subclinical abnormalities in cardiac function and that the evolution of these is slightly influenced by the reduction in GH and Sm-C. levels. In fact, while the persistence of high GH and Sm-C. levels may explain the progression of cardiac alterations in some cases, it does not in others. It is also emphasised that echocardiography appears to be the most sensitive non-invasive technique for the diagnosis and follow-up of cardiac involvement in acromegaly.
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PMID:[Cardiological findings in acromegaly]. 343 27


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