Search PubMed⌕ Search

Biomedical subjects

Andrew L Clark

Publications and source records attributed to Andrew L Clark.

70 records · Page 4Linked to original sources
PubMed2003

The relationship between cholesterol and survival in patients with chronic heart failure.

OBJECTIVES: We sought to describe the relationship between cholesterol and survival in patients with chronic heart failure (CHF). BACKGROUND: Increasing lipoprotein levels are a cardiovascular risk factor. In patients with CHF, the prognostic value of endogenous lipoproteins is not fully clarified. METHODS: A group of 114 patients with CHF recruited to a metabolic study was followed for a minimum of 12 months (derivation study). The results were applied to a second group of 303 unselected patients with CHF (validation study). The relationship between endogenous lipoproteins and survival was explored. RESULTS: In the derivation study, survival at 12 months was 78% (95% confidence interval [CI] 70% to 86%) and 56% (95% CI 51% to 62%) at 36 months. Increasing total serum cholesterol was a predictor of survival (hazard ratio 0.64, 95% CI 0.48 to 0.86), independent of the etiology of CHF, age, left ventricular ejection fraction, and exercise capacity. Receiver-operating characteristic curves demonstrated a best cut-off value of </=5.2 mmol/l (200.8 mg/dl) as being the best predictor of mortality at 12 months (sensitivity 80.0%, specificity 62.9%). In the validation population, one-year survival was 88% (95% CI 84 to 91%) and three-year survival was 68% (95% CI 63 to 73%). The chance of survival increased 25% for each mmol/l increment in total cholesterol. Survival rates above and below the cut-off value for cholesterol in patients with ischemic heart disease (n = 181) were 92% (95% CI 89 to 94) versus 75% (95% CI 64 to 85%) at one year and 72% (95% CI 67 to 76%) versus 50% (95% CI 43 to 56%) at three years. CONCLUSIONS: In patients with CHF, lower serum total cholesterol is independently associated with a worse prognosis.

Age Factors↗
PubMed2003

The prevalence of heart failure and asymptomatic left ventricular systolic dysfunction in a typical regional pacemaker population.

AIMS: To assess the prevalence of heart failure and asymptomatic left ventricular systolic dysfunction in the chronically paced population. METHODS AND RESULTS: Three hundred and seven patients were identified from attendance at routine pacemaker follow-up clinic. Subjects underwent a medical history and examination, 6-minute walk test and echocardiography. 94 (31%) had a left ventricular ejection fraction (LVEF) <40%, of whom 83 had symptoms of heart failure (70% NYHA II, 26% NYHA III and 4% NYHA IV). Heart failure was more prevalent in patients with single chamber compared to dual chamber pacemakers, (DDD(R) 18% vs 35% VVI(R), p<0.008), and those with chronic atrial fibrillation (AF) compared to those with sinus rhythm (42% vs 21%, p=0.003). Decreasing 6-minute walk distance, history of ischaemic heart disease and years of pacing were independently associated with the presence of heart failure (combined R=0.572, p<0.001). CONCLUSIONS: Heart failure due to left ventricular systolic dysfunction is common in the paced population. Only a minority of these had a pre-existing diagnosis and a smaller proportion were on 'optimal' therapy. Echocardiographic screening of this high-risk population is justified to improve rates of diagnosis and treatment of heart failure.

Adult↗
PubMed2003

Longitudinal ventricular function: normal values of atrioventricular annular and myocardial velocities measured with quantitative two-dimensional color Doppler tissue imaging.

OBJECTIVE: Quantitative 2-dimensional color Doppler tissue imaging is a new method to reveal impairment of left ventricular (LV) and right ventricular (RV) longitudinal function, which is a potential marker of early myocardial disease. The aim of this study was to obtain normal values for atrioventricular annular and regional myocardial velocities using this method. METHODS: A total of 123 healthy patients (age range: 22 to 89 years) underwent echocardiography including color Doppler tissue imaging using a scanner (Vivid 5, GE Vingmed, Horten, Norway) with postprocessing analysis (Echopac 6.3, GE Vingmed). Regional myocardial velocities were measured at 12 LV segments in 3 apical views and 2 segments of the free RV wall. Mitral annular velocities from 6 sites, and tricuspid annular velocities at its lateral site, were also assessed. At each site, systolic (S(m)), early diastolic (E(m)), and late diastolic (A(m)) velocities were measured, and the E(m)/A(m) ratio was calculated. RESULTS: Patients were classified into 4 groups aged 20 to 39, 40 to 59, 60 to 79, and >/=80 years. Mitral annular velocity and regional LV myocardial S(m) and E(m) progressively decreased with age. A(m), whereas low in the youngest age group, increased significantly in patients more than 40 years of age. The E(m)/A(m) ratio gradually declined with aging. There were no differences between age groups in S(m) measured at the tricuspid annulus and free RV wall, but the pattern of age-related changes of diastolic velocities and E(m)/A(m) ratio was the same as in the LV. Slight but significant sex-related differences were observed in middle-aged groups. The intraobserver and interobserver reproducibility was highest for atrioventricular annular velocities. CONCLUSIONS: A progressive decrease in S(m) reveals a decline in longitudinal systolic LV function with age, whereas systolic RV function remains unaffected. Atrioventricular annular velocity and regional E(m) decrease with aging in both ventricles, suggesting a deterioration in the diastolic properties of the myocardium, whereas A(m) increases from middle age implying a compensatory augmentation of atrial function. The study results can be used as reference data for the quantitative assessment of longitudinal LV and RV function in patients with cardiac disease.

Adult↗
PubMed2003

Clinical trials update from the European Society of Cardiology Heart Failure meeting: COMET, COMPANION, Tezosentan and SHAPE.

This article continues a series of reports on recent research developments in the field of heart failure. Key presentations made at the European Society of Cardiology Heart Failure Update meeting, held in Strasbourg, France are described. The COMET study showed a 17% relative risk reduction in all-cause mortality with carvedilol compared with metoprolol tartrate. The COMPANION study, as previously reported, showed encouraging results for the use of cardiac resynchronisation and implantable defibrillator therapy in patients with heart failure, but further evidence is awaited. The results of a study on tezosentan suggest that lower doses of this endothelin antagonist may be clinically more effective with fewer adverse effects compared with higher doses. The SHAPE survey of heart failure awareness in Europe identified a need for further heart failure education amongst the public, patients, their carers and primary care physicians.

Adrenergic beta-Antagonists↗
PubMed2003

Clinical trials update from the European Society of Cardiology: CHARM, BASEL, EUROPA and ESTEEM.

This article contains a series of reports on recent research developments in the field of heart failure. Reports of key presentations made at the European Society of Cardiology meeting, held in Vienna, Austria, between 30 August and 3 September 2003 are reported. In the CHARM study, candesartan reduced cardiovascular deaths and hospital admissions for heart failure, both in patients who were already taking an ACE-inhibitor and in those who were ACE intolerant. However, results in patients with preserved left ventricular function were less conclusive. The BASEL study supports the use of B-type natriuretic peptide testing to confirm the diagnosis of heart failure in patients presenting with acute dyspnoea. In EUROPA, the largest ever study of secondary prevention of coronary artery disease, long-term treatment with perindopril reduced the incidence of cardiovascular death, myocardial infarction (MI) and cardiac arrest. The ESTEEM study showed that the oral thrombin inhibitor ximelagatran plus aspirin was more effective than aspirin alone in the prophylaxis of major cardiovascular events following MI.

Angiotensin Receptor Antagonists↗
PubMed2003

Body mass and survival in patients with chronic heart failure without cachexia: the importance of obesity.

BACKGROUND: Cachexia in chronic heart failure carries a poor prognosis, but little is known about the influence of body mass on the prognosis of noncachectic heart failure patients. METHODS: We studied 589 consecutive chronic heart failure patients followed for at least a year, in whom there were accurate baseline data for body mass. RESULTS: Average age was 64.5 +/- 12.4 years, left ventricular ejection fraction (LVEF) 30.9 +/- 0.73%. Cachexia was present in 64. Noncachectic patients were divided into quintiles of body mass index (BMI), Q1 (BMI 22.2 +/- 1.5) to Q5 (BMI 34.1 +/- 2.8). There was no difference among the 5 groups in age, exercise capacity or LVEF. Survival was greatest in Q4 (1-year survival [95% confidence interval (CI)]) 0.91 (0.85-0.96) and 3-year survival 0.81 (0.73-0.89). Relative risks compared with Q4 were Q1: 2.3 (1.4-3.8); Q2: 1.7 (1.1-2.9); Q3: 1.8 (1.1-3.0); and Q5: 1.5 (0.9-2.5). In multivariate analysis of 1 year follow-up, peak oxygen consumption (hazard ratio with 95% CI) (0.89 [0.82-0.97]; P =.006), LVEF (0.94 [0.91-0.97]; P =.0002) and BMI (0.90 [0.82-0.98]; P =.02) independently predicted 1-year survival with a combined Chi;(2) value of 42.4. Age (1.01 [0.98-1.05] and diagnosis (1.56 [0.78-3.11]) was not a predictor of survival. CONCLUSION: In patients with chronic heart failure, increasing BMI is not an adverse prognostic feature. Thinner patients appear to have a poorer prognosis.

Adrenergic beta-Agonists↗
PubMed2002

Diastolic heart failure: neglected or misdiagnosed?

Recent epidemiological studies suggest that 30% to 50% of patients with heart failure (HF) have preserved left ventricular (LV) systolic function. These patients, often presumed to have diastolic heart failure (DHF), appear to have lower short-term but similar long-term mortality when compared to patients with HF and LV systolic dysfunction. Rates of recurrent hospitalization and costs of care appear similar in the two groups of patients. Therefore, DHF may contribute significantly to the burden of disease caused by HF. Exertional breathlessness, the principal symptom of HF, has many causes, including obesity, pulmonary disease and myocardial ischemia. A diagnosis of DHF by exclusion, based on symptoms in the absence of important LV systolic dysfunction or major valve disease, is unsatisfactory. Unfortunately, as yet, no reliable definition with which to make a positive diagnosis of DHF has been agreed on, frequently rendering this diagnosis uncertain. Echocardiography has several limitations, whereas hemodynamic confirmation of DHF by cardiac catheterization is potentially complex and not practically feasible for many patients. Treatment of DHF remains empirical and unsatisfactory because of the lack of large-scale randomized controlled trials in this area. Currently, three large outcome studies on DHF are in progress along with other smaller trials. These should start to provide some of the answers we need to diagnose and effectively treat DHF.

Diastole↗
PubMed2002

Nutritional abnormalities contributing to cachexia in chronic illness.

Cachexia is a common consequence of chronic illness. The nutritional abnormalities contributing to the clinical picture are often a composite of reduced appetite, dietary factors including protein, energy and micronutrient intake, malabsorption and increased consumption or loss of nutrients. In this article, using chronic heart failure as an example, we have reviewed the potential influences of chronic disease on each of these and how they might lead to the relentless progression of wasting and the poor prognosis associated with it.

Cachexia↗
PubMed2002

Clinical trials update: The Heart Protection Study, IONA, CARISA, ENRICHD, ACUTE, ALIVE, MADIT II and REMATCH. Impact Of Nicorandil on Angina. Combination Assessment of Ranolazine In Stable Angina. ENhancing Recovery In Coronary Heart Disease patients. Assessment of Cardioversion Using Transoesophageal Echocardiography. AzimiLide post-Infarct surVival Evaluation. Randomised Evaluation of Mechanical Assistance for Treatment of Chronic Heart failure.

Explore the source record for details and available documents.

Acetanilides↗
PubMed2002

Is the elevated slope relating ventilation to carbon dioxide production in chronic heart failure a consequence of slow metabolic gas kinetics?

OBJECTIVE: Patients with heart failure have slow metabolic gas exchange kinetics, which may contribute to the elevated slope of the relationship between ventilation and carbon dioxide production (Ve/Vco(2) slope). SETTING: A tertiary referral centre for cardiology. SUBJECTS: Eleven patients with stable chronic heart failure and 11 age-matched controls. DESIGN: Each subject underwent maximal bicycle-based peak exercise testing with metabolic gas exchange analysis and three further repeated tests at 15%, 25% and 50% of the load achieved at peak exercise. The ventilation and carbon dioxide production from each of these steady-state tests was used to re-calculate the Ve/Vco(2) slope and compared with the Ve/Vco(2) slope derived from the maximal test. RESULTS: Peak oxygen consumption [mean (S.D.)] was lower in heart failure patients [18.2 (4.0) vs. 31.2 (6.3) ml/kg per min; P<0.001] than in controls. The Ve/Vco(2) slope was steeper in patients than controls [32.7 (8.3) vs. 27.1 (1.6); P<0.05]. There was no difference between the Ve/Vco(2) slope reconstructed from the three steady state tests and resting data and that gained from the maximal test [35.3 (7.8) vs. 25.9 (3.2); P=0.43]. CONCLUSIONS: The elevated slope of the relationship between ventilation and carbon dioxide production is not a consequence of the short stages of a standard incremental exercise test combined with delayed metabolic gas kinetics in heart failure patients.

Aged↗
PubMed2002

Airway resistance in chronic heart failure measured by impulse oscillometry.

BACKGROUND: Patients with chronic heart failure (CHF) complain of breathlessness and fatigue on exertion, have reduced peak oxygen consumption (pV(O(2))), and an increased ventilatory response to exercise (V(E)/V(CO(2)) slope). These limitations correlate with abnormalities of spirometry (forced expiratory volume in 1 second [FEV(1)] and forced ventilatory capacity [FVC]). Increased airway resistance by increasing the work of breathing might contribute to exercise intolerance in CHF. METHODS: Impulse oscillometry (IOS) measures airway resistance and lung compliance independently of respiratory muscle strength and patient compliance. Sound waves of varying frequencies are sent into the lungs and the amplitude and phase shift of the reflected waves give a measure of airway resistance (R) and reactance (X). Twenty-three CHF patients and 18 controls underwent peak exercise testing with metabolic gas analysis and had airway resistance assessment using the Jaeger (Würtzberg, Germany) IOS system. RESULTS: Patients had a lower pV(O(2)) (18.7 (4.0) v 39.2 (8.3) mL x kg x min; P < .0001), elevated V(E)/V(CO(2)) slope (41.6 (8.1) v 27.4 (2.9)), and lower FEV(1) (2.4 (0.4) v 3.2 (0.7) L/min; P = .0001) and FVC (3.3 (0.7) v 4.1 (1.1) L; P < .005) than controls. R and X correlated with spirometric abnormalities and were different between patients and controls (R at 5 Hz 0.44 (0.16) v 0.30 (0.15) kPa (L/s); P < .005 and X at 5 Hz -0.16 (0.08) v -0.09 (0.08) kPa (L/s); P < .05). R at 5 Hz correlated with pV(O(2)) (0.46; P = .0025) and V(E)/V(CO(2)) slope (0.43; P < .05). CONCLUSION: CHF patients have elevated airway resistance and reduced reactance measured with IOS compared with control subjects.

Aged↗
PubMedDate not supplied

Diastolic heart failure: a difficult problem in the elderly.

Heart failure with normal systolic function has been equated to diastolic heart failure (DHF). DHF appears to be quite common in the elderly, especially in elderly women with hypertension. Recent epidemiologic studies suggest that 30%-50% of patients with heart failure may have DHF. Morbidity for DHF is considerable and comparable to that of heart failure with left ventricular systolic dysfunction. Both groups of patients have similar rates of recurrent hospitalization and cost of care. Long-term mortality also appears to be similar in the two groups of patients. With the aging of the population, the numbers of patients with DHF will continue to rise and are likely to contribute significantly to the burden of disease caused by heart failure. Unfortunately, as yet, no reliable definition has been found for DHF. Currently the diagnosis of DHF is often made by exclusion, and treatment is empirical and unsatisfactory because of the lack of large-scale, randomized, controlled trials in this area; however, several large and other smaller trials are currently in progress that will hopefully provide some answers.

Aged↗