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At least 703 records · Page 39Linked to original sources
PubMed2003

Acetylcholinesterase inhibition with pyridostigmine improves heart rate recovery after maximal exercise in patients with chronic heart failure.

OBJECTIVE: To characterise the effects of acetylcholinesterase inhibition with pyridostigmine on parasympathetic tone in patients with chronic heart failure (CHF). DESIGN: Prospective randomised, double blind crossover trial. SETTING: University hospital outpatient heart failure clinic. PATIENTS: 20 ambulatory subjects with stable CHF (mean age 55 years, mean ejection fraction 24%). INTERVENTIONS: Oral administration of a single dose of pyridostigmine 30 mg and matching placebo on separate days. MAIN OUTCOME MEASURES: Heart rate recovery at one minute and three minutes after completion of maximal exercise. RESULTS: Heart rate recovery at one minute after exercise was significantly greater after administration of pyridostigmine than after administration of placebo (mean (SEM) 27.4 (3.2) beats/min v 22.4 (2.4) beats/min, p < 0.01). Heart rate recovery at three minutes after exercise did not differ after administration of pyridostigmine and placebo (mean (SEM) 44.4 (3.9) beats/min v 41.8 (3.6) beats/min, NS). Peak heart rate, peak oxygen uptake, peak respiratory exchange ratio, plasma noradrenaline (norepinephrine) concentrations, and plasma brain natriuretic peptide concentrations did not differ after administration of pyridostigmine and placebo. CONCLUSIONS: Acetylcholinesterase inhibition with pyridostigmine increased heart rate recovery at one minute but not at three minutes after exercise. A specific effect of pyridostigmine on heart rate one minute after exercise suggests that pyridostigmine augments parasympathetic tone in patients with CHF.

Adult↗
PubMed1993

Coffee and tea consumption and the prevalence of coronary heart disease in men and women: results from the Scottish Heart Health Study.

STUDY OBJECTIVES: The aim was to determine if there was a relationship between coffee or tea consumption and the prevalence of coronary heart disease in Scotland. DESIGN: The relationship between self reported coffee and tea consumption and the prevalence of coronary heart disease (history, symptoms, or electrocardiographic evidence) was investigated using multiple logistic regression analysis in the Scottish Heart Health Study (SHHS), a cross sectional study. SETTING: Twenty two Scottish districts were surveyed for the SHHS between 1984 and 1986. SUBJECTS: A total of 10,359 men and women aged 40-59 years were studied. MEASUREMENTS AND MAIN RESULTS: Of the 9740 subjects who were assigned a category, 21.8% (2122) were classified as having indications of coronary heart disease. Men and women were combined in the odds ratio analysis because they showed almost identical patterns in the prevalence of coronary heart disease across the coffee and tea quarters (grouped according to consumption). Those who did not drink coffee had a significantly higher (p < 0.05) prevalence of coronary heart disease than the three groups for coffee drinkers. Adjustments for risk factors including cigarette smoking, total blood cholesterol, and diastolic blood pressure did not remove the significance of the odds ratios. There was a positive dose-response effect between tea consumption and coronary heart disease which was removed after adjustment for various risk factors. CONCLUSIONS: These findings do not support a positive relationship between coffee or tea consumption and coronary heart disease in this British study where most coffee consumed is instant coffee.

Adult↗
PubMed2004

A point-process model of human heartbeat intervals: new definitions of heart rate and heart rate variability.

Heart rate is a vital sign, whereas heart rate variability is an important quantitative measure of cardiovascular regulation by the autonomic nervous system. Although the design of algorithms to compute heart rate and assess heart rate variability is an active area of research, none of the approaches considers the natural point-process structure of human heartbeats, and none gives instantaneous estimates of heart rate variability. We model the stochastic structure of heartbeat intervals as a history-dependent inverse Gaussian process and derive from it an explicit probability density that gives new definitions of heart rate and heart rate variability: instantaneous R-R interval and heart rate standard deviations. We estimate the time-varying parameters of the inverse Gaussian model by local maximum likelihood and assess model goodness-of-fit by Kolmogorov-Smirnov tests based on the time-rescaling theorem. We illustrate our new definitions in an analysis of human heartbeat intervals from 10 healthy subjects undergoing a tilt-table experiment. Although several studies have identified deterministic, nonlinear dynamical features in human heartbeat intervals, our analysis shows that a highly accurate description of these series at rest and in extreme physiological conditions may be given by an elementary, physiologically based, stochastic model.

Adult↗
PubMed1990

Outcome of congestive heart failure, dilated cardiomyopathy, hypertrophic hyperkinetic disease, and ischemic heart disease in dialysis patients.

Congestive heart failure in dialysis patients is associated with dilated cardiomyopathy, hypertrophic hyperkinetic disease and ischemic heart disease. To determine the natural history of these four diseases, 150 dialysis patients were prospectively followed for 3-5 years. The 2-year cumulative survival rate was 33% in those with recurrent or persistent congestive heart failure vs. 80% in dialysis patients without. Survival was significantly worse in patients with an echocardiographic diagnosis of dilated cardiomyopathy compared to patients with normal echo-cardiogram (2-year survival rate 67 vs. 90%). In hypertrophic hyperkinetic disease the 2-year survival rate was 30% after entry into the study, and 43% after first admission with congestive heart failure. Symptomatic ischemic heart disease did not have an adverse impact on mortality when compared to those without ischemic heart disease. We conclude that congestive heart failure in dialysis patients has a bad prognosis. Its associated disorders include dilated cardiomyopathy and hypertrophic hyperkinetic disease, the latter being associated with a high mortality. As the prognosis for patients with overt ischemic heart disease was not different from patients without, it is likely that the underlying cardiomyopathy directly influenced survival.

Cardiomegaly↗
PubMed1971

Excitation-contraction coupling in heart. VII. Calcium accumulation in subcellular particles in congestive heart failure.

The ability of heavy microsomes and mitochondria, isolated from the control and failing hearts of genetically dystrophic hamsters (BIO 14.6 strain), to accumulate calcium was examined. The rate and extent of energy-linked calcium binding (in the absence of oxalate) by the heavy microsomes of the failing heart were markedly depressed. The calcium uptake (in the presence of 5 mM oxalate) by the heavy microsomes of the failing heart was similar to that of the control heart. On the other hand, both the rate and extent of energy-linked calcium binding (in the absence of Pi and succinate) and calcium uptake (in the presence of 4 mM Pi and 5 mM succinate) by mitochondria were greatly reduced in the failing heart in comparison to the control. No difference in the total adenosine triphosphatase activities (Ca(++)-Mg(++) stimulated) of heavy microsomes or mitochondria was observed between the control and failing hearts. These results indicate an abnormality of subcellular membranes of the failing heart to bind calcium and support the growing conviction concerning the defective "calcium pump" as a molecular abnormality associated with a moderate degree of congestive heart failure.

Adenosine Triphosphatases↗
PubMed2005

BOP, a regulator of right ventricular heart development, is a direct transcriptional target of MEF2C in the developing heart.

The vertebrate heart is assembled during embryogenesis in a modular manner from different populations of precursor cells. The right ventricular chamber and outflow tract are derived primarily from a population of progenitors known as the anterior heart field. These regions of the heart are severely hypoplastic in mutant mice lacking the myocyte enhancer factor 2C (MEF2C) and BOP transcription factors, suggesting that these cardiogenic regulatory factors may act in a common pathway for development of the anterior heart field and its derivatives. We show that Bop expression in the developing heart depends on the direct binding of MEF2C to a MEF2-response element in the Bop promoter that is necessary and sufficient to recapitulate endogenous Bop expression in the anterior heart field and its cardiac derivatives during mouse development. The Bop promoter also directs transcription in the skeletal muscle lineage, but only cardiac expression is dependent on MEF2. These findings identify Bop as an essential downstream effector gene of MEF2C in the developing heart, and reveal a transcriptional cascade involved in development of the anterior heart field and its derivatives.

Animals↗
PubMed2005

Homocysteine and heart failure: a review of investigations from the Framingham Heart Study.

High plasma homocysteine levels are associated with a moderately increased risk of cardiovascular disease, particularly of atherosclerotic events. We review the association of plasma homocysteine with heart failure, with a specific focus on a series of previously published investigations from the community-based Framingham Heart Study that evaluated the relations of plasma homocysteine levels with overt heart failure, and with its key antecedents, echocardiographic left ventricular (LV) mass and hypertension. In the Framingham sample, higher plasma homocysteine levels were associated with increased risk of new-onset heart failure in both men and women, with a more continuous and graded relation being observed in women. A positive relation between homocysteine and LV mass was observed in women, but not in men; this may underlie the stronger relations of homocysteine to heart failure risk in women. Plasma homocysteine was not associated with hypertension incidence prospectively in either sex. The relations of increased homocysteine to heart failure (in both sexes) and to greater LV mass (in women) noted in the Framingham sample should be confirmed in other community-based samples. Secondary analyses of heart failure outcomes in ongoing randomized clinical trials may provide insights into whether lowering of plasma homocysteine levels is associated with a reduction in LV mass and/or a reduction of heart failure risk.

Animals↗
PubMed1995

Heart failure progression due to secondary organ dysfunction in acute heart failure.

Although the pathophysiology of heart failure progression is important to survival it is not fully understood. In 92 patients with acute heart failure due to myocardial infarction or dilated cardiomyopathy, secondary organ dysfunction was evaluated to determine whether this factor contributed to heart failure progression and death. Forty-one patients had renal dysfunction, hepatic disease or loss of consciousness after the onset of the acute heart failure, and 26 of them (63%) died of progressive heart failure during the follow-up period of 20 months on average. The one-year survival rate was 22%. Although 51 other patients showed the same initial clinical features and cardiac function, they did not develop concurrent organ dysfunction during the course and only 11 (22%, p < 0.001) died of progressive heart failure. The one-year survival rate was 67%. The survival rate decreased in the order of renal dysfunction, hepatic disease and loss of consciousness. Transient low cardiac output of less than 2.2 l/min/m2 was more frequent in patients with organ dysfunction. It is suggested that heart failure progresses, in part, due to organ dysfunction secondary to heart failure and careful treatment to prevent organ dysfunction is important to long term survival.

Acute Disease↗
PubMed2004

Effects of pair housing on diurnal rhythms of heart rate and heart rate variability in miniature swine.

This study investigated the effects of pair housing on diurnal rhythms of heart rate and autonomic nervous activity in miniature swine. For this purpose, six adult Göttingen miniature swine were initially housed individually in an animal cage. Then, two of each swine were housed in a large cage together for 3 weeks. After that swine were separated into individual cages again. During this experimental procedure, electrocardiogram (ECG) was recorded with a Holter ECG recorder. Autonomic nervous activity was evaluated by power spectral analysis of heart rate variability. Heart rate and autonomic nervous activity clearly showed a diurnal rhythm in miniature swine housed in individual cages. When two swine were housed together, heart rate was significantly increased throughout the day and diurnal rhythm disappeared. Although these changes gradually recovered to basal levels, these parameters had not completely returned to basal levels even after 2 weeks. Heart rate was still higher than the initial level just after swine were re-housed in their own individual cages. Heart rate and autonomic nervous activity returned to basal levels about 2 weeks after re-housing. Further, heart rate in some swine decreased below their initial levels. These results suggest that it takes miniature swine at least 2 weeks to adapt to different circumstances. Furthermore, the power spectral analysis of heart rate variability can be used as a useful method in a study for answering controversial issues related to stress response.

Animals↗
PubMed2005

Urgent need to reorganize heart failure management: from paradoxes to heart failure clinics.

Despite the decreasing incidence of ischaemic heart disease and despite major medical advances in heart failure, the prevalence and mortality of chronic heart failure in the population is rising and the prognosis remains grim. Chronic heart failure is a complex disease, which is characterized by its progressive nature. In this paper, we approach the complexity of heart failure from four paradoxes: epidemiology, diagnosis, therapy and economical impact respectively. Taking these paradoxes into account, we formulate a number of essential components of alternative heart failure management programmes. Combating chronic heart failure requires the organization of centres for continuous care--as opposed to the traditional crisis intervention centres--preferably with a multidisciplinary structure to provide a "holistic approach" adapted to each patient's unique set of medical, psychosocial, physical and financial conditions. Patients taken care of in these novel multidisciplinary heart failure clinics have shown improved clinical status, decreased hospitalization rates, increased quality of life, longer life and lower costs.

Chronic Disease↗
PubMedDate not supplied

Comparative pathology of heart and liver lesions of broiler chickens that died of ascites, heart failure, and others.

Pathologic changes of 120 dead broilers from a flock of 1000 birds were compared. Macroscopically, the changes were divided into three pathologic types: ascites (retention of ascitic fluid), heart failure (right heart dilation and/or hydropericardium without retention of ascitic fluid), and others (without ascites or heart failure). The rates of ascites, heart failure, and others were 55.8% (67/120), 33.3% (40/120), and 10.8% (13/120), respectively. Histologically, cardiac histologic changes (myocardial degeneration with calcification and epicardial fibrosis) were seen in 40 of 67 (59.7%) ascites cases. Hepatic histologic changes (hepatocytic degeneration/necrosis and hepatic capsule fibrosis) were seen in 64 of 67 (95.5%) ascites cases. Cardiac histologic changes were seen in 24 of 40 heart failure cases (60.0%). Hepatic histologic changes were seen in 36 of 40 (90.0%) heart failure cases. Six of 13 others had hepatic histologic changes, but the remaining seven birds had no significant histologic changes. Ascites and heart failure cases had almost the same percentages of hepatic and cardiac histologic changes. This study indicates that two pathologic types, ascites and heart failure, may be closely related conditions and that hepatic histologic changes may be common and fundamental lesions in the pathogenesis of these pathologic types.

Animals↗
PubMed2001

Effects of nifedipine retard on heart rate and autonomic balance in patients with ischemic heart disease.

The aim of this study was to explore the effects of nifedipine retard on heart rate and autonomic balance in patients with ischemic heart disease. Fourteen patients with ischemic heart disease (12 men and two women; mean age 64 years) were administered nifedipine retard at a daily dose of 20-40 mg. Changes in heart rate and autonomic balance were studied using Holter monitoring before and after 12 weeks of nifedipine therapy Heart rate was unchanged during sleep but was higher during the day after nifedipine retard administration. The high frequency power spectrum of heart rate variability (indicating parasympathetic activity) was lower during the day after nifedipine retard therapy but was unchanged during sleep. The low frequency power to high frequency power ratio, indicating sympathetic activity was unchanged during the day and during sleep. Nifedipine retard increased the heart rate of patients with ischemic heart disease only during the day and reduced parasympathetic activity.

Aged↗
PubMed1992

A comparison of the perceived and the ECG measured heart rate during cycle ergometer, treadmill and stairmill exercise before and after perceived heart rate training.

The ability to perceive exercise heart rate before and after training was tested in six young male university students, perceptions of heart rate being compared with ECG monitored heart rates during cycle ergometry, treadmill running and stairmill climbing. Between initial and final tests, subjects undertook 13 weeks of running training (2 h/day, 3-4 days/week), and during this period they compared their perceptions of heart rate with values observed on watch-type wrist-mounted pulse monitors. Individual initial perceptions showed only a moderate correlation with ECG values. This correspondence was improved as perceptions were compared with measured heart rates over the course of training, significantly so for the mode of exercise most similar to that adopted in the training sessions (treadmill running at a heart rate of 140 beats/min). The final accuracy of perceptions at a heart rate of 140 beats/min (error 8-9 beats/min during treadmill running) compared favourably with the accuracy of either pulse counting or the traditional rating of perceived exertion as commonly observed in the exercising public. This suggests that there may be an application for perceived heart rates in regulating the intensity of prescribed exercise.

Adult↗
PubMed2005

Serum heart-type fatty acid binding protein predicts cardiac events in elderly patients with chronic heart failure.

BACKGROUND AND OBJECTIVES: Heart-type fatty acid binding protein (H-FABP) is released into the circulation from the damaged myocardium of patients with severe chronic heart failure. Chronic heart failure is the most frequent cause of death and disability in the elderly. However, there are no data for the prognostic value of H-FABP in the elderly population. This study investigated whether H-FABP can effectively predict the prognosis in elderly patients (> or = 70 years) with chronic heart failure. METHODS: Serum H-FABP levels were measured in 90 chronic heart failure patients > or =70 years old (mean age 77 +/- 4 years, range 70-92 years), and patients were followed-up for 421 +/- 326 days. RESULTS: There were 35 cardiac events (38.9%) including cardiac deaths and readmissions for worsening chronic heart failure. Multivariate analysis with the Cox proportional hazard model showed that H-FABP was the only independent predictor of cardiac events (chi2 = 6.640, p = 0.0100). Kaplan-Meier analysis revealed that H-FABP effectively risk stratified elderly patients with chronic heart failure for cardiac events. CONCLUSIONS: These findings suggest that H-FABP is a reliable marker for prognosis in elderly patients with chronic heart failure.

Aged↗
PubMed1985

Central alpha-adrenergic agonists in chronic heart failure and ischemic heart disease.

Central alpha-adrenoceptor agonists (methyldopa, clonidine, guanabenz) decrease sympathetic outflow and renin and vasopressin secretion as well as increase parasympathetic activity. These drugs are commonly employed as antihypertensives. Two other conditions, chronic heart failure and ischemic heart disease, may also benefit from central alpha-adrenergic stimulation. In both acute and chronic heart failure, central alpha-adrenoceptor agonists reduced cardiac work load by decreasing heart rate, systemic arterial pressure and reducing venous tone. Also, plasma catecholamines were decreased. Exercise at comparable work loads was achieved at a lower pressure-rate product and effort capacity was sometimes increased. Central alpha-adrenoceptor agonists increased effort capacity in patients with ischemic heart disease and angina pectoris. Again, the benefits are thought to be decreased heart rate, systemic arterial blood pressure and rate-pressure products during exercise; catecholamines are reduced in these patients as well. Central alpha-adrenoceptor agonists offer another avenue of approach to alter neurohumoral factors in congestive heart failure and ischemic heart disease and thereby produce beneficial hemodynamic response.

Adrenergic alpha-Agonists↗
PubMed1986

Left ventricular performance of the athletic heart during upright exercise: a heart rate-controlled study.

This study compares the left ventricular performance of chronically conditioned pentathletes (N = 10) with less-conditioned subjects (N = 10) during dynamic upright exercise. The pentathletes were found to have a superior treadmill performance [24 +/- 4 vs 17 +/- 2 min (SD), P less than 0.01], reduced resting heart rate (41 +/- 13 vs 62 +/- 6 bpm, P less than 0.01), and increased left ventricular mass (254 +/- 85 vs 179 +/- 35 g, P less than 0.05) compared to the control group. Radionuclide ventriculography and heart rate controlled-bicycle ergometry were employed to examine changes in left ventricular ejection fraction, end-diastolic volume, end-systolic volume, and stroke volume. Heart rate was controlled by adjusting the resistance of the ergometer until stable heart rates of 90, 110, 130, and 150 bpm were achieved. Following heart rate stabilization, 99mTc images were acquired during 3-min stages at each target heart rate level. In the pentathletes, left ventricular ejection fraction, end-diastolic volume, and stroke volume increased (P less than 0.01) during exercise, and end-systolic volume tended to decrease. No difference was noted in left ventricular ejection fraction between groups when heart rates were matched. However, the exercise-induced changes in end-diastolic volume and stroke volume were greater (P less than 0.01) in the pentathletes. In conclusion, the athletes studied relied on the same mechanism as the less-conditioned subjects for improving pump performance during exercise stress, but the athletes' ability to mobilize a greater end-diastolic volume accounts for their larger stroke output during each stage of heart rate-matched exercise.

Adult↗
PubMed1995

Body weight, heart weight, and heart-to-body weight ratio in greyhounds.

Heart and body weights were obtained from 230 Greyhounds during necropsy. Sex and age were recorded for each Greyhound. Twenty-nine racing and 21 nonracing Greyhounds among the 230 dogs were compared. Heart-to-body weight ratio was calculated. Statistical analysis was done to determine the effects of age, sex, and racing on heart and body weights and heart-to-body weight ratio. In adult Greyhounds, mean +/- SD body weight was 28.4 +/- 3.1 and 31.5 +/- 2.8 kg, heart weight was 355.6 +/- 52.8 and 381.4 +/- 50.8 g, and heart-to-body weight ratio was 1.3 +/- 0.2 and 1.2 +/- 0.2% for females and males, respectively. Heart and body weights were significantly different between sex and age groups and among nonracing and racing males. However, heart-to-body weight ratio was not significantly different among age, sex, or racing groups.

Aging↗
PubMed1993

[Heart volume determination as an indication of rejection after orthotopic heart transplantation].

Endomyocardial biopsy in cardiac transplantation is still the most exact test (gold standard) to confirm or exclude a suspected rejection. Up to now, all available noninvasive tests suffer from a low sensitivity and specificity. For a further reduction of biopsies early available noninvasive methods are desirable. In the data presented a comparison between histological findings and heart volume measurements is shown in 40 patients (112 histological findings) after orthotopic cardiac transplantation. In 46 cases with no evidence of histological rejection the echocardiographically or radiologically determined heart volume was 869 +/- 142 ml/1.73 m2 body surface area, compared to 1026 +/- 178 ml/1.73 m2 in 29 cases with mild cardiac rejection. In 37 cases with a moderate or severe rejection heart volume as 1094 +/- 181 ml/1.73 m2. The diagnosis of a moderate or severe rejection by biopsy is combined with a heart volume above 950 ml/1.73 m2 with a sensitivity of 78% and a specificity of 73%. Intramyocardial edema as well as an increase in right and left ventricular volumes due to heart failure may be the causes for heart volume increase in rejection. Thus, heart volume measurement which can be performed easily during routine echocardiography gives additional information about whether a rejection has to be assumed or can be excluded. Today, sensitivity and specificity of the test does not allow a reduction of biopsy frequency. Further investigations are necessary to analyze the course of heart volume changes during an episode of rejection.

Biopsy↗