Cardiac troponin T by Elecsys system and a rapid ELISA: analytical sensitivity in relation to the TropT (CardiacT) "bedside" test.
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Biomarkers↗
Biomedical subjects
K Dickstein
Publications and source records attributed to K Dickstein.
Cardiac troponins I and T in patients with suspected acute coronary syndrome: a comparative study in a routine setting.
We compared cardiac troponin I (cTnI), using Access, Sanofi Pasteur, and cardiac troponin T (cTnT), using Elecsys, Boehringer Mannheim, in the first two routine blood samplings in a routine panel of cardiac markers for the biochemical diagnostic evaluation of patients with symptoms of acute myocardial infarction (AMI). No significant differences in the overall clinical performances of cTnI and cTnT were observed for the diagnosis of AMI (n = 68), but cTnI demonstrated lower initial sensitivity and higher specificity compared with cTnT. cTnT was increased to higher relative values than cTnI (P = 0.023). Discordances were found between cTnI and cTnT in sample I but not in sample II; positive cTnT/negative cTnI was more common than the opposite discordance (P = 0.027). cTnT was more frequently increased in patients with unstable angina pectoris (UAP) than cTnI (P = 0.038), with no significant differences between sample I and sample II; discordant results with respect to cTnI and cTnT appeared in 6 (33%) of these patients, all of which were positive for cTnT and negative for cTnI. Four patients with UAP (22%) developed AMI within 4 months; three were associated with increased cTnI and cTnT at the time of initial testing, and one was discordant (positive cTnT). In patients classified with no acute coronary syndrome (n = 84), five concordant positives for cTnI and cTnT were observed, indicating the existence of a myocardial injury of recent origin in these patients. AMI evolved in one of these patients 5 months later. We conclude that cTnT and cTnI detect acute myocardial injury with equal clinical performance in AMI patients classified by WHO criteria. cTnT was more frequently increased in patients with UAP than cTnI, but the clinical significance of this discordance could not be determined from this study.
Acute Disease↗
Negative exercise trials in heart failure: result or design?
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Angiotensin-Converting Enzyme Inhibitors↗
[Calcium channel blockers in heart failure].
Patients with heart failure are particularly susceptible to the negative effects of calcium channel blockers because the failing heart demonstrates a defect in the delivery of calcium to the contractile proteins, and an attenuation of the normal sympathetic reflexes. Currently these drugs have no place in the treatment of heart failure caused by systolic dysfunction of the left ventricle. Calcium channel blockers should probably not be described for patients with coronary artery disease and left ventricular dysfunction. When the patient needs additional treatment for angina and beta-blockers or nitrates have not given satisfactory results, it may be appropriate to prescribe amlodipine or felodipine.
Calcium Channel Blockers↗
[Treatment of heart failure with beta-blockaders].
Since 1975 several studies have indicated that treatment with beta-adrenergic blocking drugs has a positive effect on prognosis in patients with left ventricular dysfunction. After myocardial infarction, treatment with timolol and propranolol improves prognosis in patients with symptoms of cardiomegaly and heart failure. In patients with idiopathic dilated cardiomyopathy, treatment with metoprolol improves the left ventricular ejection fraction and symptoms of heart failure, and may have a positive effect on prognosis. Recent studies of patients with chronic congestive heart failure also indicate that carvedilol has a positive effect on mortality and morbidity. The authors review some relevant studies, to stimulate the use of beta-adrenergic blocking drugs to treat certain types of heart failure.
Adrenergic beta-Antagonists↗
Comparison of the degree of hemodynamic tolerance during intravenous infusion of nitroglycerin versus nicorandil in patients with congestive heart failure.
BACKGROUND: Continuous exposure to organic nitrates is associated with substantial tachyphylaxis. This study compares the development of tolerance during continuous intravenous treatment with nitroglycerin versus nicorandil over a 24-hour period. METHODS AND RESULTS: Twenty patients with congestive heart failure and pulmonary capillary wedge pressure (PCWP) > or = 18 mm Hg were randomly assigned to nitroglycerin or nicorandil in a double-blind, crossover study. Doses were titrated to obtain a reduction of PCWP of at least 30% and then maintained. The mean pretreatment PCWP for nitroglycerin was 25.4 +/- 6.7 mm Hg, decreasing to 19.0 +/- 6.8 mm Hg at 24 hours. The values for nicorandil were 24.3 +/- 6.3 mm Hg and 15.6 +/- 4.5 mm Hg, respectively. Between-treatment difference was significant (p < 0.01). The difference between the minimal PCWP value and the 24-hour PCWP value for nitroglycerin was 5.1 mm Hg vs 1.4 mm Hg for nicorandil (p < 0.005). The mean systemic vascular resistance was 1418 +/- 355 dynes.sec.cm-5 before nitroglycerin infusion, decreasing to 1312 +/- 353 dynes.sec.cm-5 at 24 hours. Corresponding values for nicorandil were 1420 +/- 366 dynes.sec.cm-5 and 967 +/- 274 dynes.sec.cm-5. Between-treatment difference was significant (p = 0.005). Tachyphylaxis developed in 12 (60%) patients during nitroglycerin infusion versus three patients (15%) during nicorandil infusion. CONCLUSION: This study demonstrates that intravenous nicorandil administration results in significantly less hemodynamic tolerance over a 24-hour period compared with nitroglycerin. This finding may represent a clinical advantage for nicorandil in the short-term treatment of patients with congestive heart failure.
Aged↗
Effects of angiotensin II receptor blockade on N-terminal proatrial natriuretic factor plasma levels in chronic heart failure.
BACKGROUND: Plasma N-terminal proatrial natriuretic factor (N-terminal proANF) has been shown to reflect intraatrial pressures in heart failure patients, and may be used as a biochemical parameter of atrial pressures. It is still unclear how treatment of heart failure influences the relationship between hemodynamic parameters and plasma levels of N-terminal proANF. METHODS AND RESULTS: This double-blind, placebo-controlled study investigated whether 12 weeks of treatment with the angiotensin II receptor blocker losartan influenced N-terminal proANF plasma levels in 129 chronic heart failure patients. After 12 weeks of treatment, N-terminal proANF level was increased in patients given placebo by 344 +/- 1126 pmol/L, whereas in patients given 50 mg losartan, the levels had decreased by 251 +/- 886 pmol/L (P < .01 vs placebo). The change in N-terminal proANF correlated significantly with the corresponding change in pulmonary capillary wedge pressure (r = .53, P < .001). CONCLUSION: The correlation between N-terminal proANF plasma levels and pulmonary capillary wedge pressure at baseline, as well as the correlation between the changes in these parameters during treatment, suggests that plasma N-terminal proANF may be used to monitor effects on left ventricular filling pressures in patients treated with losartan.
Aged↗
Plasma N-terminal atrial natriuretic factor: a predictor of survival in patients with congestive heart failure.
BACKGROUND: Congestive heart failure results in biatrial stretch, which stimulates myocyte release of atrial natriuretic factor (1-126). The N-terminal fragment, proatrial natriuretic factor(1-98), (proANF), is released on an equimolar basis with the C-terminal (99-126) active hormone and may be assayed simply because of prolonged in vitro stability. Proatrial natriuretic factor has been shown to be predictive of clinical status in patients with congestive heart failure. This retrospective analysis was undertaken to evaluate the relationship between N-terminal atrial natriuretic factor(1-98) and survival in patients with stable congestive heart failure. METHODS AND RESULTS: Proatrial natriuretic factor was sampled from 316 patients (mean age, 68 (+/-) 11 years; 71% men) recruited from an outpatient heart failure clinic. The mean ejection fraction was 34 (+/-) 13%. Seventy-three deaths were registered during the period of data collection (42 months). Deaths per proANF quartile (n = 79) were as follows: 2 (2.5%) in quartile I. 13 (16.5%) in quartile II, 21 (26.6%) in quartile III, and 37 (46.8%) in quartile IV. The odds ratio estimates for death adjusted for age and sex were 7.6, 13.9, and 33.9 for the second, third, and fourth quartiles, respectively. Survival curves constructed according to proANF quartiles demonstrate significant differences in mortality rates. The correlation with death was greater for proANF as compared with left ventricular end-diastolic diameter (P < .001), systolic pulmonary artery pressure (P < .005), or ejection fraction (P < .05). CONCLUSION: These data indicate that the concentration of proANF is related to prognosis in patients with heart failure and that moderate elevation is associated with markedly decreased survival. Analysis should be of practical value in the assessment of prognosis in this heterogeneous population.
Adolescent↗
Drug selection for optimal treatment of hypertension in the elderly.
Progressive aging of the world's population means that choosing the most effective drugs for the elderly is becoming increasingly important. The treatment of hypertension in the elderly is complicated because of the need to consider altered pharmacokinetics, comorbidity and multiple drug therapy in these patients. Antihypertensive treatment in the elderly has important and documented beneficial effects. However, no single drug class is suitable as the first-choice therapy for all elderly patients. The most appropriate choice of an antihypertensive drug often depends on comparative adverse effect profiles and the presence of comorbid disease.
Aged↗
[Physical exercise and heart failure. A review article].
This review discusses the therapeutic value of physical exercise in patients with congestive heart failure. The possible circulatory, peripheral and metabolic mechanisms involved are discussed. Relevant clinical research in this field is reviewed. Physical training appears to be a safe and efficacious intervention in this large population.
Exercise↗
Plasma brain natriuretic peptide as an indicator of left ventricular systolic function and long-term survival after acute myocardial infarction. Comparison with plasma atrial natriuretic peptide and N-terminal proatrial natriuretic peptide.
BACKGROUND: Elevated plasma levels of atrial natriuretic peptide (ANP) and the N-terminal fragment of the ANP prohormone (N-ANP) are associated with decreased left ventricular function and decreased long-term survival after acute myocardial infarction (AMI). Previous data suggest that plasma brain natriuretic peptide (BNP) may increase proportionally more than plasma ANP after AMI and in chronic heart failure. The diagnostic and prognostic value of plasma BNP as an indicator of left ventricular dysfunction and long-term survival after AMI, relative to that of ANP and N-ANP, remain to be established. METHODS AND RESULTS: Venous blood samples for analysis of ANP, N-ANP, and BNP were obtained on day 3 after symptom onset from 131 patients with documented AMI. Left ventricular ejection fraction was determined by echocardiography in a subsample of 79 patients. Twenty-eight cardiovascular and 3 noncardiovascular deaths occurred during the follow-up period (median, 1293 days). All three peptides proved to be powerful predictors of cardiovascular mortality by univariate Cox proportional hazards regression analyses (ANP: P < .0001; N-ANP: P = .0002; BNP: P < .0001). In a multivariate model, plasma BNP (P = .021) but not ANP (P = .638) or N-ANP (P = .782) provided additional prognostic information beyond left ventricular ejection fraction. Logistic regression analysis showed that ANP (P = .003) and N-ANP (P = .027) but not BNP (P = .14) were significantly associated with a left ventricular ejection fraction < or = 45%. CONCLUSIONS: These results suggest that plasma BNP determination provides important, independent prognostic information after AMI. Although plasma ANP appears to be a better predictor of left ventricular dysfunction, plasma BNP may have greater potential to complement standard prognostic indicators used in risk stratification after AMI because of its strong, independent association with long-term survival, enhanced in vitro stability, and simplicity of analysis.
Aged↗
[Pro-atrial natriuretic factor is predictive for the clinical status of patients with heart failure].
This study was undertaken in order to evaluate the relationship between N-terminal proatrial natriuretic factor [1-98] and routinely available measures of clinical status. Odds ratio estimates demonstrated a much higher risk of presence of left ventricular dysfunction and dilatation, pulmonary hypertension, and New York Heart Association function class III or IV with increasing proANF values. Analysis is simple and can be of practical value as a supplement in the assessment of cardiac status in this heterogeneous population.
Adolescent↗
Comparison of the effects of aqueous and gellan ophthalmic timolol on peak exercise performance in middle-aged men.
PURPOSE: To compare the effects of 0.5% aqueous timolol and 0.5% timolol gellan on exercise performance in middle-aged men. METHODS: We evaluated the effects of 0.5% aqueous timolol (timolol solution, administered twice daily, and a 0.5% timolol gellan suspension that forms a gel on application to the conjunctiva (timolol gellan), administered once daily, on exercise performance in 42 healthy men with a mean age of 58 years (range, 55 to 65 years). Serum concentrations of timolol were assayed. Subjects exercised maximally on an upright cycle ergometer four times with ten-day intervals. After baseline testing, subjects were randomly assigned and crossed over in a double-masked manner to two and a half days of treatment with placebo, 0.5% timolol solution, and 0.5% timolol gellan. RESULTS: The serum timolol concentrations immediately after testing were 0.91 +/- 0.51 ng/ml for timolol solution compared to 0.71 +/- 0.46 ng/ml for timolol gellan (P < .05). The change from baseline in resting heart rate was -1.8 +/- 9.3 beats/min (P = .23) for placebo, -11.0 +/- 9.6 beats/min (P < .001) for timolol gellan. The change from baseline in peak heart rate was -0.1 +/- 7.3 beats/min (P = .92) for placebo, -15.6 +/- 5.6 beats/min (P < .001) for timolol solution, and -11.9 +/- 8.0 beats/min (P < .001) for timolol solution, and -8.5 +/- 7. 5 beats/min (P<.001) for timolol gellan. Pair-wise comparison demonstrated significantly less reduction in both resting (P < .05) and peak heart rate (P < .01) for timolol gellan vs timolol solution. CONCLUSIONS: Although both treatments caused reductions in testing and peak heart rate, timolol gellan was associated with significantly less reductions. The significant difference in serum concentrations of timolol between the two treatments is strong evidence that the difference in heart rate response was caused by reduced systemic absorption with timolol gellan.
Absorption↗
Novel drugs and current therapeutic approaches in the treatment of heart failure.
Treatment of heart failure attempts to reduce symptoms, increase functional capacity and prolong survival. Optimal therapy usually requires a combination of several drugs. At present, ACE inhibitors are the drugs of first choice, but must be combined with diuretics in symptomatic patients. Digitalis glycosides are still an important supplement to diuretics and ACE inhibitors. Specific angiotensin receptor antagonists such as losartan have an effect comparable with that of ACE inhibitors and may possess certain advantages because of their direct effect at the receptor level. Extensive research has been conducted in the treatment of heart failure. Newer direct acting vasodilators such as flosequinan and epoprostenol have demonstrated improved exercise tolerance but have an adverse effect on mortality. Positive inotropic agents consisting of a heterogeneous group of drugs have been evaluated. Although novel agents such as xamoterol, milrinone, pimobendan and vesnarinone have demonstrated improved haemodynamics and improved symptoms, they are not advisable at present due to increased mortality related to treatment or a high incidence of adverse events. beta-Blockers, used judiciously, may improve functional capacity as well as mortality and may be an important supplement to current conventional treatment. The new generation of beta-blockers with vasodilating properties such as carvedilol and bucindolol appear promising.
Anti-Arrhythmia Agents↗
Cardiac markers in the early hours of acute myocardial infarction: clinical performance of creatine kinase, creatine kinase MB isoenzyme (activity and mass concentration), creatine kinase MM and MB subform ratios, myoglobin and cardiac troponin T.
We compared early markers of acute myocardial infarction (AMI) in the first 6 h from the onset of symptoms in 133 non-traumatized patients arriving at the emergency department with chest pain suggestive of AMI. Clinical performance parameters were calculated on the basis of 45 patients with AMI and 88 patients with a non-AMI diagnosis. At admission and in the first 0-3 h after the onset of chest pain the creatine kinase-MB (CK-MB) subform ratio was the most sensitive test at a comparable specificity level of 0.95. In the time interval of 3-5 h, myoglobin, the CK-MB mass concentration and the CK-MB subform ratio were associated with the greatest areas under receiver operating characteristic (ROC) curves, but differences between these tests were small and non-significant. At 6 h from the onset of pain, differences in clinical performance between the same three tests were even smaller whether or not samples drawn after the start of thrombolytic treatment were included in the test comparison. For confirmation of AMI at 6 h after onset of pain, CK-MB (activity and mass concentration) demonstrated the highest positive likelihood ratio, and for exclusion of AMI at 6 h the CK-MB subform ratio was associated with the highest negative likelihood ratio. However, differences between the CK-MB subform ratio, CK-MB mass concentration and myoglobin were not significant as estimated by the substantial overlap between the confidence intervals of the likelihood ratios and the ROC areas at 6 h. Cardiac troponin T (cTnT) demonstrated an ROC area equal to the CK-MB isoform ratio and myoglobin at 6 h. However, the likelihood ratio for ruling out AMI was lower, mostly due to the elevated cTnT in unstable coronary disease not defined as AMI. We conclude that the CK-MB subform ratio, CK-MB mass concentration and myoglobin do not demonstrate any significant differences in clinical performance for ruling in or ruling out acute myocardial infarction at 6 h after the onset of chest pain.
Adult↗
Plasma proatrial natriuretic factor is predictive of clinical status in patients with congestive heart failure.
Atrial stretch results in myocyte release of the prohormone atrial natriuretic factor (1-126). The N-terminal (1-98) fragment, proatrial natriuretic factor (proANF) is released on an equimolar basis with the C-terminal (99-126) active hormone and may be assayed simply due to in vitro stability. This study was undertaken to evaluate the relation between proANF and routinely available measures of clinical status. ProANF was sampled from 202 patients (median age 68 years [range 15 to 85], 77% men) recruited from an active outpatient heart failure clinic. Patients were subgrouped according to New York Heart Association functional class, radionuclide ejection fraction (EF), echocardiographic left ventricular (LV) end-diastolic diameter, and Doppler-determined systolic pulmonary arterial pressure. The median proANF (pmol/L) values for patients in New York Heart Association classes I, II, III, IV were 725, 1,527, 1,750, and 5,172, respectively. The proANF value for the group with EF > 40% was 1,534 versus 1,993 for EF < or = 40% (p < 0.05). The value for the group with LV diameter < 60 mm ws 838 versus 1,751 for LV diameter > or = 60 mm (p < 0.01). The value for the group with systolic pulmonary artery pressure < 45 mm Hg was 1,241 versus 2,660 for systolic pulmonary artery pressure > or = 45 mm Hg (p < 0.01). ProANF correlated better than the other variables with New York Heart Association functional class and was more closely associated with noninvasive measurements than New York Heart Association functional class.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Losartan in heart failure. Hemodynamic effects and tolerability. Losartan Hemodynamic Study Group.
BACKGROUND: The aim of the present study was to assess the short- and long-term effects of multiple doses of the angiotensin II receptor antagonist losartan in heart failure. METHODS AND RESULTS: A multicenter, placebo-controlled, oral, multidose (2.5, 10, 25, and 50 mg losartan once daily) double-blind comparison in patients with symptomatic heart failure and impaired left ventricular function (ejection fraction < 40%). Invasive 24-hour hemodynamic assessment was performed after the first dose and after 12 weeks of treatment. Clinical status and tolerability of treatment with losartan over the 12-week period were also evaluated. One hundred fifty-four patients were enrolled, of which 134 met the protocol criterion of baseline pulmonary capillary wedge pressure > or = 13 mm Hg. During short-term administration, systemic vascular resistance (SVR) (largest reduction against placebo of 197 dyne.s-1.cm-5 at 4 hours) and blood pressure fell significantly with 50 mg, lesser decreases were seen with 25 mg, and no discernible effects were seen with 2.5 and 10 mg. After 12 weeks of treatment, similar effects were seen on SVR and blood pressure (maximal fall in SVR against placebo, 318 dyne.s-1.cm-5 at 5 hours with 50 mg). In addition, pulmonary capillary wedge pressure fell with 2.5, 25, and 50 mg (largest reduction against placebo of 6.3 mm Hg at 6 hours with 50 mg), cardiac index rose with 25 and 50 mg, and heart rate was lower with all active treatment groups. Active treatment was well tolerated, and excess cough was not reported. CONCLUSIONS: This study showed that oral losartan administered to patients with symptomatic heart failure resulted in beneficial hemodynamic effects with short-term administration, with additional beneficial hemodynamic effects seen after 12 weeks of therapy. Clear effects were seen with both 25 and 50 mg, with the greatest effect seen with 50 mg.
Aged↗
[Chronic left heart ventricle failure and inotropic stimulation].
Congestive left heart failure can be treated using three main strategies: change preload to optimize the Frank-Starling relationship, decrease after-load to reduce external work and increase cardiac contractility by inotropic stimulation. The third option is reviewed in this article, which discusses the pharmacological and clinical effects of different inotropic drugs as known in 1994. It is concluded that digitalis should be considered apart from other inotropic drugs. Even when in sinus rhythm, digitalis seems reasonable as an adjuvans to after-load reduction and diuretics. Chronic use of other inotropic drugs for congestive left heart failure is not recommended.
Adrenergic beta-Agonists↗