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Biomedical subjects

R Freudenberger

Publications and source records attributed to R Freudenberger.

9 recordsLinked to original sources
PubMed2000

The effect of coenzyme Q10 in patients with congestive heart failure.

BACKGROUND: Coenzyme Q10 is commonly used to treat congestive heart failure on the basis of data from several unblinded, subjective studies. Few randomized, blinded, controlled studies have evaluated objective measures of cardiac performance. OBJECTIVE: To determine the effect of coenzyme Q10 on peak oxygen consumption, exercise duration, and ejection fraction. DESIGN: Randomized, double-blind, controlled trial. SETTING: University and Veterans Affairs hospitals. PATIENTS: 55 patients who had congestive heart failure with New York Heart Association class III and IV symptoms, ejection fraction less than 40%, and peak oxygen consumption less than 17.0 mL/kg per minute (or <50% of predicted) during standard therapy were randomly assigned. Forty-six patients completed the study. INTERVENTION: Coenzyme Q10, 200 mg/d, or placebo. MEASUREMENTS: Left ventricular ejection fraction (measured by radionuclide ventriculography) and peak oxygen consumption and exercise duration (measured by a graded exercise evaluation using the Naughton protocol) with continuous metabolic monitoring. RESULTS: Although the mean (+/-SD) serum concentration of coenzyme Q10 increased from 0.95+/-0.62 microg/mL to 2.2+/-1.2 microg/mL in patients who received active treatment, ejection fraction, peak oxygen consumption, and exercise duration remained unchanged in both the coenzyme Q10 and placebo groups. CONCLUSION: Coenzyme Q10 does not affect ejection fraction, peak oxygen consumption, or exercise duration in patients with congestive heart failure receiving standard medical therapy.

Antioxidants↗
PubMed2000

Effects of BG9719 (CVT-124), an A1-adenosine receptor antagonist, and furosemide on glomerular filtration rate and natriuresis in patients with congestive heart failure.

OBJECTIVES: To determine the effects of furosemide and the selective A1 adenosine receptor BG9719 on renal function in patients with congestive heart failure (CHF). BACKGROUND: Studies suggest that adenosine may affect renal function by various mechanisms, but the effects of blockade of this system in humans is unknown. In addition, the effects of a therapeutic dose of furosemide on glomerular filtration rate (GFR) and renal plasma flow (RPF) in heart failure patients are controversial. METHODS: On different days, 12 patients received placebo, BG9719 and furosemide. Glomerular filtration rate, RPF and sodium and water excretion were assessed immediately following drug administration. RESULTS: Glomerular filtration rate was 84 +/- 23 ml/min/1.73m2 after receiving placebo, 82 +/- 24 following BG9719 administration and a decreased (p < 0.005) 63 +/- 18 following furosemide. Renal plasma flow was unchanged at 293 +/- 124 ml/min/1.73m2 on placebo, 334 +/- 155 after receiving BG9719 and 374 +/- 231 after receiving furosemide. Sodium excretion increased from 8 +/- 8 mEq following placebo administration to 37 +/- 26 mEq following BG9719 administration. In the six patients in whom it was measured, sodium excretion was 104 +/- 78 mEq following furosemide administration. CONCLUSIONS: Natriuresis is effectively induced by both furosemide and the adenosine A1 antagonist BG9719 in patients with CHF. Doses of the two drugs used in this study did not cause equivalent sodium and water excretion but only furosemide decreased GFR. These data suggest that adenosine is an important determinant of renal function in patients with heart failure.

Adult↗
PubMed2000

Depression is common and precludes accurate assessment of functional status in elderly patients with congestive heart failure.

BACKGROUND: Congestive heart failure (CHF) and depression are independently known to result in physical decline and diminished functional capacity in the general population. The prevalence and relationship of depressive symptoms in CHF to physical limitations has not been objectively examined. METHODS AND RESULTS: The Center for Epidemiological Studies Depression Scale (CES-D) was used to ascertain depressive symptoms in 33 elderly ambulatory individuals with CHF. Self-report assessment of functional status, cardiopulmonary exercise testing (CPX), and measurement of energy expenditure by doubly labeled water and Caltrac Accelerometer (Muscle Dynamics, Torrance, CA) were performed. Depressed and nondepressed groups were compared. Forty-two percent of the patients scored in the depressed range (CES-D score of 16 or greater). There were no differences in demographic variables or severity of illness between the depressed and nondepressed patients. Energy expenditure was comparable across groups. Although obtaining similar maximal heart rate and maximal oxygen consumption (VO2max) on CPX, the depressed group showed less exertion on exercise testing with a significantly lower respiratory quotient (P = .017). CONCLUSION: Depressive symptoms were common and unrelated to the severity of CHF. Although depressed individuals tended to report worse physical functioning than nondepressed individuals, objective assessment of energy expenditure was comparable. Depressed patients appear to underestimate their functional ability. Subsequently, inaccurate assessment of functional status may occur.

Activities of Daily Living↗
PubMed2000

Characteristics of patients referred for cardiac transplantation: implications for the donor organ shortage.

BACKGROUND: When the decision is made to proceed with cardiac transplantation, the risk/benefit ratio for continued medical therapy in that particular patient must be weighed against the risk/benefit ratio associated with cardiac transplantation. This can only be accomplished while the patient is on maximal medical therapy. METHODS: To better define the appropriateness of patients being referred for consideration of transplant, we examined the records of 100 consecutive adult patients referred to a cardiac transplant program. RESULTS: Two of five patients referred for transplantation had at least one contraindication for transplantation. Twenty percent of the patients were not treated with angiotensin-converting enzyme inhibitors and did not have any documented reason for undertreatment. Of those deemed too well for cardiac transplantation, 84% were alive and either class I or II (mean follow-up 21 months). CONCLUSIONS: We found the majority to be undertreated or with an absolute contraindication to transplantation. Of those deemed too well for transplantation after appropriate treatment, 84% were alive and well.

Adolescent↗
PubMed1999

Antithrombotic effect of FK506 vs cyclosporine in cardiac transplant recipients: potential implications in transplant arteriopathy.

BACKGROUND: An activated coagulation system has been implicated as a potential initiating or inciting factor in the development and progression of cardiac allograft vasculopathy (CAV). METHODS: By performing ex vivo perfusion studies of blood thrombogenicity under constant rheologic conditions and with a constant substrate, we sought to determine the relative effects on the coagulation system of FK506 vs cyclosporine in patients who have undergone cardiac transplantation. RESULTS-CONCLUSIONS: Compared with cyclosporine, FK506 significantly decreased the propensity to form thrombus; this suggests that FK506 may have a favorable impact on the development of CAV.

Blood Coagulation↗
PubMed1999

Effects of exercise training on peak performance and quality of life in congestive heart failure patients.

BACKGROUND: Exercise programs for patients with heart failure have often enrolled and evaluated relatively healthy, young patients. They also have not measured the impact of exercise performance on daily activities and quality of life. METHODS AND RESULTS: We investigated the impact of a 6-month supervised and graded exercise program in 33 elderly patients with moderate to severe heart failure randomized to usual care or an exercise program. Six of 17 patients did not tolerate the exercise program. Of those who did, peak oxygen consumption increased by 2.4 +/- 2.8 mL/kg/min (P < .05) and 6-minute walk increased by 194 ft (P < .05). However, outpatient energy expenditure did not increase, as measured by either the doubly labeled water technique or Caltrac accelerometer. Perceived quality of life also did not improve, as measured by the Medical Outcomes Study, Functional Status Assessment, or Minnesota Living With Heart Failure questionnaires. CONCLUSION: Elderly patients with severe heart failure can safely exercise, with an improvement in peak exercise tolerance. However, not all patients will benefit, and daily energy expenditure and quality of life do not improve to the same extent as peak exercise.

Activities of Daily Living↗
PubMed1997

Therapeutic options in advanced heart failure.

Treatment of advanced heart failure is usually a challenge. The successful use of beta-blockers to alleviate mild to moderate symptoms of cardiac dysfunction suggests that even severe cases of heart failure may be reversible. Transplantation remains the only sure way to obtain a fully functional heart, but new medications, mechanical devices, and surgical procedures could eventually prove to be alternatives.

Adrenergic beta-Antagonists↗
PubMed1996

Combined alpha-beta blockade (doxazosin plus metoprolol) compared with beta blockade alone in chronic congestive heart failure.

There has been growing evidence for the benefits of beta blockers, but alpha blockers have not shown sustained benefits in chronic congestive heart failure (CHF). Thirty patients with moderate to severe CHF (New York Heart Association class II to IV) were sequentially assigned to receive metoprolol 6.25 mg with the alpha-1 antagonist doxazosin 4 mg/day or metoprolol alone. The dose of metoprolol was gradually increased to a target dose of 50 mg orally twice daily. Hemodynamic measurements were obtained before drug therapy, 2 hours after the first dose of combined alpha-beta therapy or metoprolol alone, and after 3 months of continuous treatment. Nuclear ejection fraction, plasma norepinephrine, and submaximal and maximal exercise capacity were also measured before and after chronic therapy. With initial combined drug administration, mean arterial pressure, left ventricular filling pressure, and systemic vascular resistance decreased significantly compared with results after metoprolol alone. However, after 3 months of continuous therapy, both treatment groups showed similar and significant reductions in systemic vascular resistance and heart rate, with significant increases in cardiac index, stroke volume index, stroke work index, ejection fraction, and exercise capacity. Furthermore, the next dose of chronic combined medication no longer showed vasodilating effects. Chronic therapy with fixed-dose doxazosin and increasing doses of metoprolol produced identical effects as those seen in patients receiving metoprolol alone.

Adrenergic alpha-Antagonists↗