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Query: UMLS:C0018801 (heart failure)
 72,216 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

There are obviously several causes of myocardial dysfunction but energy deficiency of the myocytes may play a significant role and probably is a common mechanism during the progression of myocardial failure. Theoretically, a poor utilization efficiency of oxygen may be due to exhaustion of the myocardial stores of bioenergetics. In this report the authors review their biochemical results from measurements of coenzyme Q10 (CoQ10) levels in blood and human endomyocardial biopsies using an HPLC method from patients with suspected myocardial disease (n = 45). The levels of CoQ10, which has a key role in the respiratory chain and the synthesis of ATP, was found to be significantly decreased in various groups of patients with myocardial failure (dilated and restrictive cardiomyopathy and alcoholic heart disease) as compared to "normal" myocardium (0.42 +/- 0.04 micrograms/mg dry weight). The deficiency of CoQ10 was more pronounced with increasing symptoms; e.g. patients with dilated cardiomyopathy in NYHA Classes III and IV had lower tissue CoQ10 content than those of Classes I and II (0.28 +/- 0.04 vs. 0.37 +/- 0.06 micrograms/mg, p less than 0.001). Nearly two thirds of a series of 40 patients in severe heart failure (Classes III and IV) treated with CoQ10, 100 mg daily, in an open, controlled design showed subjective and objective improvement. Clinical responders were 69% and 43% of patients with cardiomyopathy and ischaemic heart disease, respectively. The results suggest that CoQ10 is a novel and effective breakthrough in heart-failure therapy and it appears safe, as no adverse reactions were registered. The through in heart-failure therapy and it appears safe, as no adverse reactions were registered.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Coenzyme Q10: clinical benefits with biochemical correlates suggesting a scientific breakthrough in the management of chronic heart failure. 227 93

Since the therapeutic advances prolong survival of many patients suffering from cardiovascular pathology--the prevalence of chronic heart failure (CHF) had just doubled, being a common entity in a world whose individuals present a great increase in longevity. These considerations justify the renewed interest in this particular syndrome. Concepts, pathophysiology and compensatory mechanisms are briefly summarized, putting emphasis on the advantage of pharmacologically interrupt the vicious loop of the compensatory mechanisms, that could play a deleterious role in the syndrome. Neurohormonal responses and the "pivotal" role of angiotensine II in CHF pathology are also discussed, emphasizing the benefits of angiotensin converting enzyme inhibitors (ACEI) when treating patients presenting heart failure. Questions addressed to its prescription at an early stage, (classes II and III of NYHA--to prevent the progressive exhaustion of the failing heart) are also considered. When approaching the preventive measures in a wide perspective, primary, secondary and tertiary types of preventive options are described. ACEI use for the least advanced clinical stages of CHF (class II and III) would represent a tertiary type of CHF prevention.
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PMID:[Congestive heart insufficiency. Prophylactic aspects]. 269

The muscle cells of cardiac atria contain many secretory granula with a prohormone of 126 amino acids (ANF(1-126)). Distension of the atria causes exocytosis of the granula with cleavage of the prohormone into the hormone ANF(99-126) or alpha-ANP and the N-terminal fragment ANF(1-98) with an as yet unknown role. The plasma concentration of the hormone in normal man is in the range of 10 pM (30 pg/ml) with a plasma half-life of several minutes and a release rate of 2-3 ng/kg per minute. The plasma concentration changes in parallel with the intake of sodium chloride and is elevated acutely by all interventions which increase the blood volume, or which cause its redistribution towards the cardiopulmonary compartment. Infusions of the hormone cause diuresis and natriuresis, inhibition of the renin-angiotensin-aldosterone system and of sympathetic activity and augmentation of tissue filtration. Thus, a hormonal feedback loop for cardiac unloading by limiting the plasma volume could be assumed. However, the ANF infusion rates necessary for eliciting these actions in man induce ANF plasma concentrations above physiological levels. On the other hand, a physiological role of the hormone in this regulation is suggested by observations during long-term administration of the hormone, which demonstrate actions of the hormone at physiological plasma levels. Furthermore, experiments with injection of ANF antibodies indicate a synergistic action of ANF, together with reflexes in response to atrial distension. ANF acts by activating specific high affinity membrane receptors, resulting in intracellular cGMP formation and cGMP release into plasma and urine. These ANF receptors are "down-regulated" by infusions of the hormone and by chronic volume expansion. In fetal circulation and in congestive heart failure, there is also augmented prohormone synthesis in the cardiac ventricles, which may then contribute to the release of the hormone. Although during cardiac failure the ANF plasma levels are augmented up to 30-fold, and the atrial prohormone content is reduced, there is no indication for an exhaustion of hormone synthesis or for resetting of stimulated hormone release. In addition to its role as a peripheral hormone for "cardiac unloading", ANF occurs in the central nervous system as a neuropeptide, which might also be involved in blood pressure and volume regulation.
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PMID:[Atrial natriuretic hormone in the human]. 296 72

Cardiopulmonary exercise testing includes the monitoring of respiratory gases and airflow to determine oxygen uptake, carbon dioxide (CO2) production, respiratory rate, tidal volume, and minute ventilation during a graded maximal exercise test. A plateau in oxygen uptake, which occurs despite an increase in work load, and which is termed maximal oxygen uptake (VO2 max), correlates with the maximal exercise cardiac output and can therefore be used to grade the severity of heart failure. The anaerobic threshold occurs at 60 to 70% of VO2 max and is another indicator of the severity of heart failure and, when attained, indicates that the patient is close to performing a maximal test. We have found VO2 max and anaerobic threshold to be objective measures of efficacy of both investigational and noninvestigational therapy in patients with heart failure. A pulmonary limitation to exercise can be identified by the failure to attain anaerobic threshold or VO2 max, as well as exhaustion of the ventilatory reserve, as estimated by maximal voluntary ventilation. Thus, cardiopulmonary exercise testing can be used to (1) grade the severity of heart failure, (2) objectively follow the response to therapy, and (3) differentiate a cardiac from a pulmonary limitation to exercise.
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PMID:Cardiopulmonary exercise testing in congestive heart failure. 313 38

Plasma catecholamine concentrations were measured in 15 patients (six male) aged 14-63 years attending the casualty department with acute severe asthma (peak expiratory flow 27% (SEM 3%) of predicted). Nine patients were admitted and six were not. The plasma noradrenaline concentration, reflecting sympathetic nervous discharge, was two to three times normal in all patients and was significantly higher in those who required admission compared with those discharged home (mean 7.7 (SEM 0.6) v 4.7 (0.5) nmol/l (1.3 (SEM 0.1) v 0.8 (0.08) ng/ml); p less than 0.001). Plasma adrenaline concentration, however, was not increased in any patient. This surprising failure of the plasma adrenaline concentration to increase during the stress of an acute attack of asthma was unexplained and contrasts with the pronounced rise in plasma adrenaline and noradrenaline concentrations in acute myocardial infarction, heart failure, and septicaemia. The failure of plasma adrenaline concentration to increase in acute asthma is unlikely to be explained by adrenal exhaustion, but it may be another example of impaired adrenaline secretion in asthma.
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PMID:Circulating catecholamines in acute asthma. 391 81

Patients with congestive heart failure have been considered to have augmented sympathetic drive both at rest and during dynamic exercise. The augmentation observed during exercise may be related to the state of near exhaustion experienced by patients with heart failure at relatively low work loads. To compare the response of the sympathetic nervous system to exercise in normal subjects and patients with heart failure when they are working in a comparable physiologic frame of reference, the data for both groups can be expressed as percent peak oxygen consumption achieved (percent peak VO2) rather than as a function of absolute oxygen consumption (VO2). Ten healthy control subjects and 31 patients with chronic clinical class II and III heart failure were studied during upright maximal bicycle exercise. Eighteen of the 31 patients had primary cardiomyopathy and 13 had ischemic cardiomyopathy. The average ejection fraction at rest was 24 +/- 10% (+/- SD) in the group with heart failure. Heart rate, systolic blood pressure, VO2 and plasma norepinephrine levels were measured at rest and throughout exercise. When the data were expressed as a function of percent peak VO2 achieved, patients with heart failure demonstrated a flatter slope (p = 0.004) than normal in the response of plasma norepinephrine to exercise, indicating a relative blunting of sympathetic drive. This was accompanied by attenuated heart rate (p = 0.001) and blood pressure (p less than 0.001) responses. These differences were not apparent when the data are expressed as a function of absolute VO2.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Relative attenuation of sympathetic drive during exercise in patients with congestive heart failure. 397 88

In patients with chronic heart failure whose cardiac output response to exercise is impaired, determination of anaerobic threshold may provide a useful and objective approach to grade the severity of heart failure. In such patients performing upright treadmill exercise to exhaustion, this study examined the reproducibility of the response of cardiac output and mixed venous lactate concentration when the exercise test was repeated the same or next day, the nature of this response after rest and exercise cardiac output levels were augmented by the cardiotonic agent amrinone and the response of lactate during symptom-limited submaximal exercise performed at either aerobic or anaerobic levels of work for each patient. Findings were: 1) the response of cardiac output and mixed venous lactate was reproducible (p less than 0.05) when assessed either the same or the next day; 2) when exercise cardiac output was increased (p less than 0.05) by oral amrinone therapy, the increase in lactate was delayed (p less than 0.05) to higher levels of muscular work and this was not true when cardiac output was unchanged; and 3) only submaximal anaerobic exercise was symptom limited and associated with an increase in lactate concentration. Thus, the lactate response and anaerobic threshold determination should prove useful to assess the severity of chronic stable heart failure and its response to pharmacologic intervention. The submaximal anaerobic exercise test may provide additional insights into the effort intolerance these patients experience.
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PMID:Lactate production during maximal and submaximal exercise in patients with chronic heart failure. 403 Dec 84

The acute hemodynamic and metabolic effects of captopril therapy were studied in 12 patients with severe heart failure during maximal exercise performed on an upright bicycle ergometer. During the control period, exhaustion occurred after 4.2 +/- 2.7 minutes of exercise. Cardiac index increased from 1.54 +/- 0.36 l/min/m2 at rest to 3.39 +/- 1.54 l/min/m2 (p less than 0.001) at exhaustion; systemic arteriovenous oxygen difference increased from 8.8 +/- 2.1 to 12.8 +/0 2.4 ml/100 ml (p less than 0.001) and oxygen uptake from 3.4 +/- 0.5 to 10.8 +/- 3.0 ml/kg/min (p less than 0.001). Pulmonary arterial oxygen content decreased from 7.3 +/- 1.3 to 3.7 +/- 1.5 ml/100 ml (p less than 0.001) and femoral vein oxygen content from 5.0 +/- 1.7 to 2.5 +/- 1.2 ml/100 ml (p less than 0.001). During captopril therapy, cardiac index significantly increased both at rest (1.83 +/- 0.54 vs 1.54 +/- 0.36 l/min/m2, p less than 0.01) and during maximal exercise (3.67 +/- 1.51 vs 3.39 +/- 1.54 l/min/m2, p less than 0.01). Systemic arteriovenous oxygen difference decreased significantly at rest, from 8.8 +/- 2.1 to 7.7 +/- 2.1 ml/100 ml (p less than 0.01) and during maximal exercise from 12.8 +/- 2.4 to 12.3 +/- 2.2 ml/100 ml (p less than 0.01). Pulmonary arterial oxygen content at exhaustion was significantly higher during captopril therapy than during the control period (4.1 +/- 1.1 vs 3.7 +/- 1.5 ml/100 ml, p less than 0.05), while femoral venous blood content was unchanged. Captopril therapy did not significantly increase maximal oxygen uptake or exercise duration. Thus, the acute administration of captopril to patients with severe heart failure does not increase exercise capacity despite improved cardiac performance. Moreover, captopril therapy does not acutely result in metabolic benefits to the skeletal muscles during exercise.
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PMID:Regional and systemic metabolic effects of angiotensin-converting enzyme inhibition during exercise in patients with severe heart failure. 629 1

Treatment with vasodilators in heart failure has not always produced a useful improvement in the haemodynamic responses to exercise, and in many cases early drug tolerance has further limited the potential of this type of treatment. In a study to evaluate the efficacy of felodipine, a new calcium antagonist with selective vasodilator properties, in the management of congestive heart failure 10 patients with congestive heart failure underwent treadmill exercise testing before and during oral treatment with felodipine 30 mg daily. At every level of exercise felodipine lowered the pulmonary capillary wedge pressure, whereas cardiac index and stroke index increased considerably. The haemodynamic improvement was associated with an increase in the duration of exercise to exhaustion. Importantly, these beneficial effects were sustained throughout four weeks of treatment without evidence of drug tolerance. These observations suggest a useful role for felodipine in the long term management of congestive heart failure.
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PMID:Effects of vasodilator treatment with felodipine on haemodynamic responses to treadmill exercise in congestive heart failure. 646 18

The acute hemodynamic and metabolic effects of dobutamine administered during exercise were studied in 8 patients with severe chronic heart failure. Exercise was performed on an upright bicycle ergometer using a graded protocol. During exercise performed without administration of dobutamine, exhaustion occurred after 4.5 +/- 1.2 minutes of exercise. The cardiac index increased from 1.61 +/- 0.25 to 2.67 +/- 0.59 liters/min/m2 (p less than 0.001), the arteriovenous oxygen difference from 7.8 +/- 1.7 to 12.5 +/- 2.4 ml/100 ml (p less than 0.001), and oxygen uptake from 7.9 +/- 3.0 to 41.2 +/- 15.7 mg/100 ml (p less than 0.001). During exercise performed with the administration of dobutamine, the cardiac index was significantly greater than during the control state, 3.23 +/- 0.78 versus 2.67 +/- 0.59 liters/min/m2 (p less than 0.001), while the arteriovenous oxygen difference was significantly lower, 11.2 +/- 2.1 vs 12.5 +/- 2.4 ml/100 ml (p less than 0.01). The arterial lactate level was not significantly changed, 45.3 +/- 17.6 versus 41.2 +/- 15.7 mg/100 ml. Although the dobutamine level tended to increase maximal oxygen uptake compared with the control period of exercise, 9.1 +/- 1.2 versus 8.5 +/- 1.4 ml/kg/min (p less than 0.05), it did not significantly increase exercise capacity, 4.8 +/- 1.5 versus 4.5 +/- 1.2 min. Thus administration of dobutamine in patients with severe chronic heart failure increased the cardiac index during maximal exercise but failed to increase exercise capacity. Since arteriovenous oxygen difference is reduced, dobutamine probably increases blood flow to the nonexercising tissues and not to the actively metabolizing muscles.
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PMID:Failure of dobutamine to increase exercise capacity despite hemodynamic improvement in severe chronic heart failure. 684 56


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