Hemodynamic effects of bilevel nasal positive airway pressure ventilation in patients with heart failure. (73/12919)

AIMS: Benefits of nasal continuous positive airway pressure (CPAP) in patients presenting with chronic heart failure (CHF) are controversial. The purpose of this study was to compare the hemodynamic effects of CPAP and bilevel positive airway pressure (BiPAP) in patients with or without CHF. METHODS AND RESULTS: Twenty patients with CHF and 7 with normal left ventricular function underwent cardiac catheterization. Measurements were made before and after three 20-min periods of BiPAP: expiratory positive airway pressure (EPAP) = 8 cm H2O and inspiratory positive airway pressure (IPAP) = 12 cm H2O, EPAP = 10 cm H2O and IPAP = 15 cm H2O, and CPAP = EPAP = IPAP = 10 cm H2O administered in random order. Positive pressure ventilation decreased cardiac output (CO) and stroke volume. No change was observed in either pulmonary or systemic arterial pressure. There was no difference in the hemodynamic effects of the three ventilation settings. Only mean pulmonary wedge pressure (MPWP) and heart rate were lower with CPAP than with BiPAP. CO decreased only in patients with low MPWP (+info)

Contribution of lung function to exercise capacity in patients with chronic heart failure. (74/12919)

BACKGROUND: The importance of exercise capacity as an indicator of prognosis in patients with heart disease is well recognized. However, factors contributing to exercise limitation in such patients have not been fully characterized and in particular, the role of lung function in determining exercise capacity has not been extensively investigated. OBJECTIVE: To examine the extent to which pulmonary function and respiratory muscle strength indices predict exercise performance in patients with moderate to severe heart failure. METHODS: Fifty stable heart failure patients underwent a maximal symptom-limited cardiopulmonary exercise test on a treadmill to determine maximum oxygen consumption (VO2max), pulmonary function tests and maximum inspiratory (PImax) and expiratory (PEmax) pressure measurement. RESULTS: In univariate analysis, VO2max correlated with forced vital capacity (r = 0.35, p = 0.01), forced expiratory volume in 1 s (r = 0.45, p = 0.001), FEV1/FVC ratio (r = 0.37, p = 0.009), maximal midexpiratory flow rate (FEF25-75, r = 0. 47, p < 0.001), and PImax (r = 0.46, p = 0.001), but not with total lung capacity, diffusion capacity or PEmax. In stepwise linear regression analysis, FEF25-75 and PImax were shown to be independently related to VO2max, with a combined r and r2 value of 0. 56 and 0.32, respectively. CONCLUSIONS: Lung function indices overall accounted for only approximately 30% of the variance in maximum exercise capacity observed in heart failure patients. The mechanism(s) by which these variables could set exercise limitation in heart failure awaits further investigation.  (+info)

Differences in drug treatment of chronic heart failure between European countries. (75/12919)

AIMS: A large number of drugs are currently used for the treatment of chronic heart failure. Treatment for other cardiovascular disorders has been shown to differ between countries. In this study we examined whether this would also be true in heart failure. METHODS AND RESULTS: We studied patients with moderate to severe heart failure, who were enrolled in an international survival study, and compared patterns of drug use between the nine countries that each included >50 patients in the study. The results were analysed to determine whether observed differences between countries could be explained by differences in the patients recruited. 1825 patients were studied (range 81-427 per country). By trial protocol, most patients were treated with angiotensin converting enzyme (ACE) inhibitors (92%) and all with diuretics, but the proportion of patients taking high doses of these drugs was markedly different between countries. Large differences were also observed in the use of digoxin (overall 64%, 39% in the U.K. to 87% in Germany) and antiarrhythmics (overall 25%, with the highest use 44% in France). The use of beta-blockers and calcium antagonists was low (overall 6% and 8%, respectively), but also different between countries. Anticoagulants (overall 43%) were used in many patients in the Netherlands and Switzerland (around 70%), while antiplatelets (overall use 30%) were most often prescribed in Denmark (51%). CONCLUSIONS: Large differences in drug use and dosing for patients with advanced heart failure are observed between (European) countries. None of these differences could be explained by differences in patient characteristics, and whether they are related to factors such as tradition, economic circumstances and national guidelines, etc. is unknown.  (+info)

Effects of education and support on self-care and resource utilization in patients with heart failure. (76/12919)

AIMS: To test the effect of education and support by a nurse on self-care and resource utilization in patients with heart failure. METHODS: A total of 179 patients (mean age 73, 58% male, NYHA III-IV) hospitalized with heart failure were evaluated prospectively. Patients were randomized to the study intervention or to 'care as usual'. The supportive educative intervention consisted of intensive, systematic and planned education by a study nurse about the consequences of heart failure in daily life, using a standard nursing care plan developed by the researchers for older patients with heart failure. Education and support took place during the hospital stay and at a home visit within a week of discharge. Data were collected on self-care abilities, self-care behaviour, readmissions, visits to the emergency heart centre and use of other health care resources. RESULTS: Education and support from a nurse in a hospital setting and at home significantly increases self-care behaviour in patients with heart failure. Patients from both the intervention and the control group increased their self-care behaviour within 1 month of discharge, but the increase in the intervention group was significantly more after 1 month. Although self-care behaviour in both groups decreased during the following 8 months, the increase from baseline remained statistically significant in the intervention group, but not in the control group. No significant effects on resource utilization were found. CONCLUSIONS: Intensive, systematic, tailored and planned education and support by a nurse results in an increase in patients' self-care behaviour. No significant effects were found on use of health care resources. Additional organisational changes, such as longer follow-up and the availability of a heart failure specialist would probably enhance the effects of education and support.  (+info)

Cytokines and neurohormones relating to body composition alterations in the wasting syndrome of chronic heart failure. (77/12919)

BACKGROUND: Chronic heart failure is one of a number of disorders associated with the development of a wasting syndrome. The precise mechanisms of this remain unknown, but previous studies have suggested a role for immune and neurohormonal factors. METHODS: We aimed to investigate in detail the differences in body composition (dual X-ray absorptiometry) and the relationship to candidate biochemical factors of the immune, neurohormonal and metabolic systems in 15 healthy controls, 36 stable non-cachectic and 18 cachectic patients with chronic heart failure. RESULTS: Non-cachectic patients showed reduced leg lean tissue (-9.1%, P<0.01) compared to controls. Cachectic patients had significantly reduced lean (-21.0% vs controls, -19.9% vs non-cachectics), fat (-33.0% vs controls, -37. 0% vs non-cachectics) and bone tissue (-17.5% vs controls, -15.9% vs non-cachectics) (all P<0.0001). Cachectic patients showed a significantly increased cortisol/dehydroepiandrosterone ratio (+203% vs controls, P<0.0001; +89% vs non-cachectics, P=0.0011) and increased cytokine levels (TNF-alpha, soluble TNF-receptor 1, interleukin-6). The levels of catabolic hormones and cytokines correlated significantly with reduced muscle and fat tissue content and reduced bone mass. CONCLUSION: Peripheral loss of muscle tissue is a general finding in chronic heart failure. The wasting in cardiac cachexia affects all tissue compartments and is significantly related to neurohormonal and immunological abnormalities.  (+info)

Relationship between TIMI frame count and clinical outcomes after thrombolytic administration. Thrombolysis In Myocardial Infarction (TIMI) Study Group. (78/12919)

BACKGROUND: The corrected TIMI frame count (CTFC) is the number of cine frames required for dye to first reach standardized distal coronary landmarks, and it is an objective and quantitative index of coronary blood flow. METHODS AND RESULTS: The CTFC was measured in 1248 patients in the TIMI 4, 10A, and 10B trials, and its relationship to clinical outcomes was examined. Patients who died in the hospital had a higher CTFC (ie, slower flow) than survivors (69. 6+/-35.4 [n=53] versus 49.5+/-32.3 [n=1195]; P=0.0003). Likewise, patients who died by 30 to 42 days had higher CTFCs than survivors (66.2+/-36.4 [n=57] versus 49.9+/-32.1 [n=1059]; P=0.006). In a multivariate model that excluded TIMI flow grades, the 90-minute CTFC was an independent predictor of in-hospital mortality (OR=1.21 per 10-frame rise [95% CI, 1.1 to 1.3], an approximately 0.7% increase in absolute mortality for every 10-frame rise; P<0.001) even when other significant correlates of mortality (age, heart rate, anterior myocardial infarction, and female sex) were adjusted for in the model. The CTFC identified a subgroup of patients with TIMI grade 3 flow who were at a particularly low risk of adverse outcomes. The risk of in-hospital mortality increased in a stepwise fashion from 0.0% (n=41) in patients with a 90-minute CTFC that was faster than the 95% CI for normal flow (0 to 13 frames, hyperemia, TIMI grade 4 flow), to 2.7% (n=18 of 658 patients) in patients with a CTFC of 14 to 40 (a CTFC of 40 has previously been identified as the cutpoint for distinguishing TIMI grade 3 flow), to 6.4% (35/549) in patients with a CTFC >40 (P=0.003). Although the risk of death, recurrent myocardial infarction, shock, congestive heart failure, or left ventricular ejection fraction 20 to +info)

Determinants and prognostic implications of persistent ST-segment elevation after primary angioplasty for acute myocardial infarction: importance of microvascular reperfusion injury on clinical outcome. (79/12919)

BACKGROUND: Despite early recanalization of an occluded infarct artery, reperfusion at the level of the microcirculation may remain impaired owing to a process of microvascular reperfusion injury. METHODS AND RESULTS: Microvascular reperfusion injury was studied in 91 patients with acute myocardial infarction (AMI) by evaluation of the resolution of ST-segment elevation after successful PTCA. Impaired microvascular reperfusion, defined as the presence of persistent (>/=50% of initial value) ST-segment elevation (ST >/=50%) at the end of coronary intervention, was observed in 33 patients (36%) and was independently correlated with low systolic pressure on admission and high age. Patients >/=55 years of age with systolic pressures /=50% versus ST <50%, P=0.01); nonfatal MI rate, 9% versus 2% (P=0.1); and total major adverse cardiac event (MACE) rate, 45% versus 15% (P<0.005). ST >/=50% was the most important independent determinant of MACE with an adjusted risk ratio of 3.4. CONCLUSIONS: Impaired microvascular reperfusion, as evidenced by ST >/=50% after successful recanalization, occurs in more than one third of our AMI patients, especially in older patients with low systolic pressure. Its detrimental implications on clinical outcome reinforce the need to develop adjunctive agents that attenuate the process of reperfusion injury.  (+info)

Kallidin- and bradykinin-degrading pathways in human heart: degradation of kallidin by aminopeptidase M-like activity and bradykinin by neutral endopeptidase. (80/12919)

BACKGROUND: Since kinins kallidin (KD) and bradykinin (BK) appear to have cardioprotective effects ranging from improved hemodynamics to antiproliferative effects, inhibition of kinin-degrading enzymes should potentiate such effects. Indeed, it is believed that this mechanism is partly responsible for the beneficial effects of angiotensin-converting enzyme (ACE) inhibitors. In the heart, enzymes other than ACE may contribute to local degradation of kinins. The purpose of this study was to investigate which enzymes are responsible for the degradation of KD and BK in human heart tissue. METHODS AND RESULTS: Cardiac membranes were prepared from the left ventricles of normal (n=5) and failing (n=10) hearts. The patients had end-stage congestive heart failure as the result of coronary heart disease or idiopathic dilated cardiomyopathy. Heart tissue was incubated with KD or BK in the presence or absence of enzyme inhibitors. We found no difference in the enzymes responsible for kinin metabolism or their activities between normal and failing hearts. Thus KD was mostly converted into BK by the aminopeptidase M-like activity. When BK was used as substrate, it was converted into an inactive metabolite BK-(1-7) mostly (80% to 90%) by the neutral endopeptidase (NEP) activity, with ACE unexpectedly playing only a minor role. The low enzymatic activity of ACE in the cardiac membranes, compared with that of NEP, was not due to chronic ACE inhibitor therapy, because the cardiac ACE activities of patients, whether receiving ACE inhibitors or not, and of normal subjects were all equal. CONCLUSIONS: The present in vitro study shows that in human cardiac membranes, the most critical step in kinin metabolism, that is, inactivation of BK, appears to be mediated mostly by NEP. This observation suggests a role for NEP in the local control of BK concentration in heart tissue. Thus inhibition of cardiac NEP activity could be cardioprotective by elevating the local concentration of BK in the heart.  (+info)