Impedance cardiography: More questions than answers

Thoracic electrical bioimpedance, also known as impedance cardiography (ICG), is a noninvasive method to obtain hemodynamic measurements, including cardiac output. Recently, there has been a flurry of reports on the clinical use of ICG. Authors have suggested that ICG measurements are useful for a myriad of situations, including diagnosis of heart failure, monitoring of a patient's clinical status, and assisting in medicine titration decisions. However, data continue to suggest poor correlation between current generation ICG devices and invasive measurements of cardiac output, especially in heart failure patients. ICG is also not able to accurately measure left ventricular filling pressures. There are limited data demonstrating any improved outcomes using ICG in the clinical setting. Given the available data, ICG use should be limited to the research setting.

Vasopressin v(2) receptor blockade with tolvaptan versus fluid restriction in the treatment of hyponatremia

Hyponatremia is common and is associated with a poor prognosis. Traditional management with fluid restriction is difficult to maintain, and it is often ineffective. The objective of this study was to determine the effect of tolvaptan versus fluid restriction on serum sodium concentration. The study was a prospective, multicenter, randomized, active-controlled, open-label trial. Twenty-eight hospitalized subjects with serum sodium <135 mmol/L were enrolled in the study. After a 2-day run-in period, subjects were randomized 2:1 to tolvaptan alone (n = 17) or fluid restriction (1,200 ml/day) plus placebo (n = 11). Oral tolvaptan was started at 10 mg/day and increased to 60 mg/day as needed. Treatment was continued for up to 27 days, and follow-up continued for up to 65 days. The primary end point was the normalization of serum sodium, defined as >135 mmol/L or a > or =10% increase from baseline. At the last inpatient visit, serum sodium had increased by 5.7 +/- 3.2 mmol/L in the tolvaptan group and 1.0 +/- 4.7 mmol/L in the fluid restriction group (p = 0.0065). No differences in adverse events were observed between the groups. In conclusion, tolvaptan appears to be more effective than fluid restriction at correcting hyponatremia in hospitalized subjects, without an increase in adverse events.

Acute Congestive Heart Failure in the Emergency Department

Acute heart failure and cardiogenic pulmonary edema is a common cause of respiratory distress among patients presenting to the emergency department. The emergency department is frequently the primary entry point into the health care system for these patients and is the site of initial stabilization, evaluation, and management of the patient.Emergency physicians, alongside cardiologists, play a critical role as these patients are treated in the emergency department and transferred to the cardiac ICU. The approach to the critically ill patient who has heart failure should be multidisciplinary and involve the emergency physician and the cardiologist who will care for the patient.

The adequacy of laboratory monitoring in patients treated with spironolactone for congestive heart failure

OBJECTIVES

This study was designed to determine the adequacy of monitoring patients receiving spironolactone as well as spironolactone's relationship to hyperkalemia.

BACKGROUND

After the Randomized Aldactone Evaluation Study (RALES) demonstrated a 30% mortality benefit for treating severe heart failure patients with spironolactone, acceptance of this drug was overwhelming. Hyperkalemia and worsening renal function were rare in RALES, but laboratory monitoring was frequent. In clinical practice, the incidence of hyperkalemia and worsening renal function and adequacy of follow-up is unknown.

METHODS

We reviewed the monitoring of congestive heart failure (CHF) patients with spironolactone initiation after publication of RALES. All potassium and creatinine determinations at baseline and within three months following therapy initiation were assessed. Increased potassium was defined as any [K] > or = 5.5 mEq/l and severe hyperkalemia as any [K] > or = 6.0.

RESULTS

A total of 840 patients had new prescriptions for spironolactone. Of these, 91% had baseline laboratory values, and 34% did not have any serum potassium or creatinine determined within three months. Patients seen in the cardiology clinic were more likely to have appropriate follow-up (p < or = 0.001). Of 551 patients with follow-up laboratory values determined, 15% developed hyperkalemia and 6% developed severe hyperkalemia. Fifty-one patients (9%) developed renal dysfunction, of whom 25 developed hyperkalemia within three months. Hyperkalemia developed in 48 of 138 (35%) patients with baseline creatinine > or = 1.5 mg/dl and 12 of 19 (63%) with baseline creatinine > or = 2.5 mg/dl.

CONCLUSIONS

Many patients treated with spironolactone for CHF do not receive needed follow-up of potassium or creatinine concentrations, although hyperkalemia and renal dysfunction are common. Elevated baseline creatinine predicts patients at high risk. Physician education of the risks of spironolactone and the need for follow-up is essential.

Consistency of the beneficial effect of metoprolol succinate extended release across a wide range dose of angiotensin-converting enzyme inhibitors and digitalis

BACKGROUND

The effects of beta-blockade with different extent of angiotensin-converting enzyme inhibitors (ACEI) and digitalization are unknown. To assess the effect of metoprolol succinate controlled release/extended release (CR/XL) combined with high versus low doses of ACEI and digitalis, we analyzed data from The Metoprolol CR/XL Randomized Intervention Trial in Chronic Heart Failure (MERIT-HF) in which patients with heart failure and left ventricular ejection fraction < or =40% were randomized to metoprolol CR/XL versus placebo.

METHODS AND RESULTS

Outcome was analyzed separately for those on a low dose (< or =median) of the ACEI or digitalis versus high dose (> median). The mean dose of ACEI in the high-dose group (n = 1457) was 3 times higher than that in the low-dose group (n = 2094). Mortality was reduced to a similar extent in the high- and low-dose ACEI subgroups (RR = .69 versus .64, respectively). Corresponding figures for combined mortality/all hospitalization and for mortality/hospitalization for heart failure were .85 versus .83, and .70 versus .68, respectively. Likewise, reduction in total mortality with metoprolol CR/XL was similar in patients receiving no digitalis (n = 1447; RR = .56), low dose (n = 1122; RR = .71), or high dose (n = 1421; RR = .71).

CONCLUSION

This analysis of MERIT-HF demonstrates consistent and similar improvement in outcome of patients receiving metoprolol CR/XL when combined with either a high or low dose of an ACEI or digitalis, or no digitalis at all. Thus regardless of ACEI and digitalis dose and whether patients are treated with digitalis or not, it is very important to add a beta-blocker to the existing heart failure therapy. beta-blockers should not be withheld until target doses of ACEI have been achieved.

Effect of kidney transplantation on left ventricular systolic dysfunction and congestive heart failure in patients with end-stage renal disease

OBJECTIVES

We examined the impact of kidney transplantation on left ventricular ejection fraction (LVEF) in end-stage renal disease (ESRD) patients with congestive heart failure (CHF).

BACKGROUND

The ESRD patients with decreased LVEF and a poor New York Heart Association (NYHA) functional class are not usually referred for transplant evaluations, as they are considered to be at increased risk of cardiac and surgical complications.

METHODS

Between June 1998 and November 2002, 103 recipients with LVEF < or =40% and CHF underwent kidney transplantation. The LVEF was re-assessed by radionuclide ventriculography gated-blood pool (MUGA) scan at six and 12 months and at the last follow-up during the post-transplant period.

RESULTS

Mean pre-transplant LVEF% increased from 31.6 +/- 6.7 (95% confidence interval [CI] 30.3 to 32.9) to 52.2 +/- 12.0 (95% CI 49.9 to 54.6, p = 0.002) at 12 months after transplantation. There was no perioperative death. After transplantation, 69.9% of patients achieved LVEF > or =50% (normal LVEF). A longer duration of dialysis (in months) before transplantation decreased the likelihood of normalization of LVEF in the post-transplant period (odds ratio 0.82, 95% CI 0.74 to 0.91; p < 0.001). The NYHA functional class improved significantly in those with normalization of LVEF (p = 0.003). After transplantation, LVEF >50% was the only significant factor associated with a lower hazard for death or hospitalizations for CHF (relative risk 0.90, 95% CI 0.86 to 0.95; p < 0.0001).

CONCLUSIONS

Kidney transplantation in ESRD patients with advanced systolic heart failure results in an increase in LVEF, improves functional status of CHF, and increases survival. To abrogate the adverse effects of prolonged dialysis on myocardial function, ESRD patients should be counseled for kidney transplantation as soon as the diagnosis of systolic heart failure is established.

Current concepts for the neurohormonal management of left ventricular dysfunction after myocardial infarction

The importance of addressing neurohormonal activation in patients after a myocardial infarction is now well-appreciated. Inhibition of the renin-angiotensin-aldosterone axis and the sympathetic nervous system can result in improved cardiac function and survival. As we learn more about other systems, we should be able to realize further benefits. In particular, the roles of endothelin, matrix metalloproteinases, and cytokines in remodeling are being investigated, with the potential to result in better outcomes for patients.

Nesiritide does not improve renal function in patients with chronic heart failure and worsening serum creatinine

BACKGROUND

Nesiritide (synthetic human brain natriuretic peptide) is approved for the treatment of symptomatic heart failure. However, studies of brain natriuretic peptide in patients with heart failure have come to conflicting conclusions about effects on glomerular filtration rate (GFR), effective renal plasma flow, natriuresis, and diuresis.

METHODS AND RESULTS

To identify a population at high risk of renal dysfunction with conventional treatment, we selected patients with a creatinine level increased from baseline (within 6 months). We examined the effects of nesiritide on GFR (measured by iothalamate clearance), renal plasma flow (measured by para-amino hippurate clearance), urinary sodium excretion, and urine output in a double-blind, placebo-controlled, crossover study. Patients received nesiritide (2 microg/kg IV bolus followed by an infusion of 0.01 microg/kg per minute) or placebo for 24 hours on consecutive days. Nesiritide and placebo data were compared by repeated-measures analysis and Student t test. We studied 15 patients with a recent mean baseline creatinine of 1.5+/-0.4 mg/dL and serum creatinine of 1.8+/-0.8 mg/dL on admission to the study. There were no differences in GFR, effective renal plasma flow, urine output, or sodium excretion for any time interval or for the entire 24-hour period between the nesiritide and placebo study days. For 24 hours, urine output was 113+/-51 mL/h with placebo and 110+/-56 mL/h with nesiritide. GFR during placebo was 40.9+/-25.9 mL/min and with nesiritide was 40.9+/-25.8.

CONCLUSIONS

Nesiritide did not improve renal function in patients with decompensated heart failure, mild chronic renal insufficiency, and renal function that had worsened compared with baseline. The lack of effect may be related to renal insufficiency, hemodynamic alterations, sodium balance, severity of heart failure, or drug dose. Understanding the importance of these issues will permit effective and appropriate use of nesiritide.

The influence of age, gender, and race on the prevalence of depression in heart failure patients

OBJECTIVES

The goal of this study was to determine the prevalence of depression in an out-patient heart failure (HF) population; its relationship to quality of life (QOL); and the impact of gender, race, and age.

BACKGROUND

Most studies of depression in HF have evaluated hospitalized patients (a small percentage of the population) and have ignored the influence of various patient characteristics. Although reported depression rates among hospitalized patients range from 13% to 77.5%, out-patient studies have been small, have reported rates of 13% to 42%, and have not adequately accounted for the impact of age, race, or gender.

METHODS

A total of 155 patients with stable New York Heart Association functional class II, III, and IV HF and an ejection fraction <40% were given questionnaires to assess QOL and depression. These included the Medical Outcomes Study Short Form, the Minnesota Living with Heart Failure questionnaire, and the Beck Depression Inventory (BDI). Depression was defined as a score on the BDI of > or =10.

RESULTS

A total of 48% of the patients scored as depressed. Depressed patients tended to be younger than non-depressed patients. Women were more likely (64%) to be depressed than men (44%). Among men, blacks (34%) tended to have less depression than whites (54%). Depressed patients scored significantly worse than non-depressed patients on all components of both the questionnaires measuring QOL. However, they did not differ in ejection fraction or treatment, except that depressed patients were significantly less likely to be receiving beta-blockers.

CONCLUSIONS

Depression is common in patients with HF, with age, gender, and race influencing its prevalence in ways similar to those observed in the general population. These data suggest that pharmacologic or non-pharmacologic treatment of depression might improve the QOL of HF patients.

Incidence, predictors at admission, and impact of worsening renal function among patients hospitalized with heart failure

OBJECTIVES

The goal of this study was to determine the prevalence of worsening renal function (WRF) among hospitalized heart failure (HF) patients, clinical predictors of WRF, and hospital outcomes associated with WRF.

BACKGROUND

Impaired renal function is associated with poor outcomes among chronic HF patients.

METHODS

Chart reviews were performed on 1,004 consecutive patients admitted for a primary diagnosis of HF from 11 geographically diverse hospitals. Cox regression model analysis was used to identify independent predictors for WRF, defined as a rise in serum creatinine of >0.3 mg/dl (26.5 micromol/l). Bivariate analysis was used to determine associations of development of WRF with outcomes (in-hospital death, in-hospital complications, and length of stay).

RESULTS

Among 1,004 HF patients studied, WRF developed in 27%. In the majority of cases, WRF occurred within three days of admission. History of HF or diabetes mellitus, admission creatinine > or =1.5 mg/dl (132.6 micromol/l), and systolic blood pressure >160 mm Hg were independently associated with higher risk of WRF. A point score based on these characteristics and their relative risk ratios predicted those at risk for WRF. Hospital deaths (adjusted risk ratio [ARR] 7.5; 95% confidence intervals [CI] 2.9, 19.3), complications (ARR 2.1; CI 1.5, 3.0), and length of hospitalizations >10 days (ARR 3.2, CI 2.2, 4.9) were greater among patients with WRF.

CONCLUSIONS

Worsening renal function occurs frequently among hospitalized HF patients and is associated with significantly worse outcomes. Clinical characteristics available at hospital admission can be used to identify patients at increased risk for developing WRF.

Relationship between heart failure treatment and development of worsening renal function among hospitalized patients

BACKGROUND

Among patients who are hospitalized with heart failure (HF), worsening renal function (WRF) is associated with worse outcomes. Whether treatment for HF contributes to WRF is unknown. In this study, we sought to assess whether acute treatment for patients who were hospitalized with HF contributes to WRF.

METHODS

Data were collected in a nested case-control study on 382 subjects who were hospitalized with HF (191 patients with WRF, defined as a rise in serum creatinine level >26.5 micromol/L [0.3 mg/dL], and 191 control subjects). The association of medications, fluid intake/output, and weight with WRF was assessed.

RESULTS

Calcium channel blocker (CCB) use and loop diuretic doses were higher in patients on the day before WRF (25% vs 10% for CCB; 199 +/- 195 mg vs 143 +/- 119 mg for loop diuretics; both P <.05). There were no significant differences in the fluid intake/output or weight changes in the 2 groups. Angiotensin-converting enzyme (ACE) inhibitor use was not associated with WRF. Other predictors of WRF included elevated creatinine level at admission, uncontrolled hypertension, and history of HF or diabetes mellitus. Higher hematocrit levels were associated with a lower risk. Vasodilator use was higher among patients on the day before WRF (46% vs 35%, P <.05), but was not an independent predictor in the multivariable analysis.

CONCLUSIONS

Several medical strategies, including the use of CCBs and a higher dose of loop diuretics, but not ACE inhibitors, were associated with a higher risk of WRF. Although assessment of inhospital diuresis was limited, WRF could not be explained by greater fluid loss in these patients. Determining whether these interventions are responsible for WRF or are markers of higher risk requires further investigation.

Perioperative beta-blockade: a survey of physician attitudes in the department of veterans Affairs

OBJECTIVE

To delineate clinician opinion on the efficacy, safety, and logistics of perioperative beta-adrenergic blockade for patients undergoing noncardiac surgery.

DESIGN

Survey of opinions and clinical practices.

SETTING

Internet-based survey form.

PARTICIPANTS

Members of the Associations of Veterans Affairs Anesthesiologists and Surgeons and chiefs of cardiology in centers with surgical programs.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

One hundred twenty-seven responses from 62 Veterans Affairs Medical Centers in 35 states (57 anesthesiologists, 45 surgeons, 25 cardiologists) were analyzed. Ninety-two percent agreed that it is effective in reducing short-term adverse outcomes, declining to 60% for long-term outcome. There was greater enthusiasm for its use in patients with known coronary artery disease (87%) than in patients with risk factors only (72%). Although 66% considered it efficacious in vascular surgery, only 30% were convinced it was for nonvascular surgery (with a similar distribution for safety in these settings). Preoperative use was favored (94%), with most physicians favoring use within 1 week of surgery (52%). Most favored 1 to 2 weeks of postoperative therapy (43%), with the remainder favoring shorter (19%) or longer (35%) durations. Although 71% of clinicians reported frequent use in their practice, most believed its use was largely informal by their colleagues (83%) and rarely based on a formal clinical pathway (13%).

CONCLUSION

A wide range of opinions by clinicians regarding the efficacy, safety, and logistics of perioperative beta-adrenergic blockade was encountered, suggesting need for additional clinical research and centralized efforts at increasing compliance with existing guidelines.

Sex, Digitalis, and the Sodium Pump

Foxglove and its constituents therapeutic agent digitalis have been used for centuries for the treatment of heart failure. All digitalis-like cardiotonic steroids enhance heart contraction through a mechanism involving the inhibition of the Na(+),K(+)- ATPase. Recently, Rathore and colleagues reported that sex-based differences may exist in the efficacy of digoxin for the treatment of heart failure. The authors of the study found that female patients exhibited increased risk of death associated with digoxin therapy, whereas male patients appeared to have no increased risk of death related to digoxin therapy. Blaustein and colleagues delve into the report and discuss possible explanations for these findings, suggest alternative ones, and advocate for enrolling greater numbers of women in clinical studies.

The prognostic importance of different definitions of worsening renal function in congestive heart failure

BACKGROUND

Worsening renal function in patients hospitalized for heart failure portends a poor prognosis. However, criteria used to define worsening renal function are arbitrary, and the implications of different definitions remain unclear. We therefore compared the prognostic importance of various definitions of worsening renal function in 1,002 patients hospitalized for congestive heart failure (CHF).

METHODS AND RESULTS

The patient population was 49% female, aged 67 +/- 15 years. Twenty-three percent had a prior history of renal failure, 73% had known depressed ejection fraction, and 63% had known CHF. On admission to the hospital, 47% were receiving ACE inhibitors, 22% beta-blockers, 70% diuretics and 6% NAID's. 72% developed increased serum creatinine during the hospitalization, with 20% developing an increase of > or = 0.5 mg/dL. Worsening renal function predicted both in-hospital mortality and length of stay > 10 days. Even an increased creatinine of 0.1 mg/dL was associated with worse outcome. Sensitivity for death decreased from 92% to 65% as the threshold for increased creatinine was raised from 0.1 to 0.5 mg/dL, with specificity increasing from 28% to 81%. At a threshold of a 0.3 mg/dL increase, sensitivity was 81% and specificity was 62% for death and 64% and 65% for length of stay >10 days. Adding a requirement of final creatinine of > or = 1.5 mg/dL improved specificity.

CONCLUSIONS

This analysis demonstrates that any detectable decrease in renal function is associated with increased mortality and prolonged hospital stay. This suggests that therapeutic interventions which improve renal function might be beneficial.

Metoprolol CR/XL in female patients with heart failure: analysis of the experience in Metoprolol Extended-Release Randomized Intervention Trial in Heart Failure (MERIT-HF)

BACKGROUND

Underrepresentation of women in heart failure clinical trials has limited conclusions regarding the effect of various management strategies on survival in women with heart failure and decreased left ventricular ejection fraction (LVEF).

METHODS AND RESULTS

MERIT-HF (Metoprolol Extended-Release Randomized Intervention Trial in Heart Failure) was a randomized, placebo-controlled study, the purpose of which was to evaluate the effect of metoprolol controlled-release/extended-release (CR/XL) in 3991 patients with New York Heart Association class II to IV heart failure and LVEF < or =0.40. We performed a post hoc analysis to evaluate the effect of metoprolol CR/XL on outcome in women (n=898), including the outcome in 183 women with severe heart failure (New York Heart Association class III/IV and LVEF < 0.25). Treatment with metoprolol CR/XL in women resulted in a 21% reduction in the primary combined end point of all-cause mortality/all-cause hospitalizations (164 versus 137 patients; P=0.044). The number of cardiovascular hospitalizations was reduced by 29% (164 versus 120; P=0.013), and hospitalization for worsening heart failure was reduced by 42% (95 versus 56; P=0.021). Similar results were noted in the subgroup of women with severe heart failure, with a 57% reduction in cardiovascular hospitalizations (63 versus 30; P=0.005) and a 72% reduction in hospitalization due to worsening heart failure (46 versus 14; P=0.0004). A pooling of mortality results from MERIT-HF, the Cardiac Insufficiency Bisoprolol Study (CIBIS II), and the Carvedilol Prospective Randomized Cumulative Survival Study (COPERNICUS) showed very similar survival benefits in women and men.

CONCLUSIONS

The beneficial effects of metoprolol CR/XL extend to women with heart failure, including women with clinically stable severe heart failure.

BG9719 (CVT-124), an A1 adenosine receptor antagonist, protects against the decline in renal function observed with diuretic therapy

BACKGROUND

Adenosine may adversely affect renal function via its effects on renal arterioles and tubuloglomerular feedback, but effects of adenosine blockade in humans receiving furosemide and ACE inhibitors is unknown.

METHODS AND RESULTS

This was a randomized, double-blind, ascending-dose, crossover study evaluating 3 doses of BG9719 in 63 patients with congestive heart failure. Patients received placebo or 1 of 3 doses of BG9719 on 1 day and the same medication plus furosemide on a separate day. Renal function and electrolyte and water excretion were assessed. BG9719 alone caused an increase in urine output and sodium excretion (P<0.05). Although administration of furosemide alone caused a large diuresis, addition of BG9719 to furosemide increased diuresis, which was significant at the 0.75-microg/mL concentration. BG9719 alone improved glomerular filtration rate (GFR) at the 2 lower doses. Furosemide alone caused a decline in GFR. When BG9719 was added to furosemide, however, creatinine clearance remained at baseline at the 2 lower doses.

CONCLUSIONS

In patients with congestive heart failure on standard therapy, including ACE inhibitors, BG9719 increased both urine output and GFR. In these same patients, furosemide increased urine output at the expense of decreased GFR. When BG9719 was given in addition to furosemide, urine volume additionally increased and there was no deterioration in GFR. A1 adenosine antagonism might preserve renal function while simultaneously promoting natriuresis during treatment for heart failure.

Tolerability of beta-blocker initiation and titration in the Metoprolol CR/XL Randomized Intervention Trial in Congestive Heart Failure (MERIT-HF)

BACKGROUND

beta-Blockade improves survival when administered over a long period of time to patients with heart failure. However, the time course of any possible deterioration during the titration phase has not been reported.

METHODS AND RESULTS

We looked at evidence of clinical deterioration in the Metoprolol CR/XL Randomized Intervention Trial in Congestive Heart Failure (MERIT-HF) by analyzing events and symptoms during the first 90 days. During titration, the Kaplan-Meier curves for the combined end point of all-cause mortality/all-cause hospitalization were similar in all patients randomized, with no significant difference in favor of placebo at any visit or in any of the analyzed subgroups (New York Heart Association class II, III/IV, or III/IV with ejection fraction <0.25, heart rate less-than-or-equal 76 bpm, and systolic blood pressure less-than-or-equal 120 mm Hg). The curves started to diverge in favor of beta-blockade after 60 days. Low heart rate was the main factor that limited titration. In New York Heart Association class III/IV, 5.9% of the patients receiving placebo discontinued study medicine during the first 90 days compared with 8.1% of those receiving metoprolol CR/XL (P=0.037 unadjusted, P=NS adjusted); corresponding figures in those with New York Heart Association class III/IV and ejection fraction <0.25 were 7.1% and 8.0% (P=NS). From day 90 until the end of the study, more patients in the placebo group discontinued study medicine in all subgroups. There was no change in diuretic or ACE inhibitor dosing with beta-blocker titration. Most patients reported no change in symptoms of breathlessness or fatigue during the titration phase.

CONCLUSIONS

When carefully titrated, metoprolol CR/XL can be given safely to the overwhelming majority of patients with stable mild to moderate heart failure, with minimal side effects or deterioration.

Renal effects of adenosine A1-receptor antagonists in congestive heart failure

Renal function is a very important prognostic indicator in patients with congestive heart failure. While some of the prognostic importance of poor renal function is related to the worse physiology associated with it, there are suggestions that the dysfunction itself is detrimental. Recently, it has been shown that adenosine may mediate much kidney activity. In addition to vasoconstrictive and vasodilatory effects, adenosine is intrinsic to the tubuloglomerular feedback which occurs when an acute increase in sodium levels in the proximal tubule feeds back to decrease glomerular filtration. Adenosine works via both adenosine A1 and A2 receptors. A1-receptor antagonists decrease afferent arteriolar pressure, and increase urine flow and sodium excretion. Studies suggest that A1-receptor antagonists cause a diuretic effect not by a change in the renal haemodynamics, but by the inhibition of water and sodium reabsorption in tubular sites secondary to direct tubuloglomerular feedback. Less consistent has been the occasional finding of increased glomerular filtration rate despite the lack of improved renal plasma flow. Clinically important questions are: what role adenosine plays in causing the poor renal function associated with heart failure and what A1-receptor antagonists do in such situations? If an A1-receptor antagonist could cause diuresis while maintaining or improving glomerular filtration, it would be a useful adjunct in the treatment of severe heart failure. We evaluated the effects of the A1-receptor antagonist CVT-124 (BG-9719) in heart failure patients. CVT-124 increased sodium excretion without decreasing glomerular filtration rate. These data suggest that adenosine might be an important determinant of renal function in patients with heart failure.

Exercise in the geriatric patient with congestive heart failure

The benefits of exercise in the elderly patient with heart failure have been well documented, but the studies have been limited by restrictive inclusion criteria. Most studies have involved patients who are younger and healthier than those normally seen in clinical practice. Improvements in neurohormonal, metabolic, and vascular status have been well documented in the relatively young patients who have been evaluated. Consequently, peak exercise time, oxygen consumption, submaximal exercise, and quality of life have also improved. Studies suggest that older, more severely limited patients may also benefit from exercise. However, they are less likely to tolerate an exercise program and may not improve their quality of life if the exercise is excessive. Caution is warranted when exercise is prescribed to elderly patients with heart failure.

Comparative effects of three beta blockers (atenolol, metoprolol, and propranolol) on survival after acute myocardial infarction

The beneficial impact of beta blockade after an acute myocardial infarction (AMI) is clear, but beta-adrenergic blockers differ in multiple characteristics, including lipophilicity and selectivity. The impact of these factors on the effects of beta blockade is unknown. We therefore compared the effects of different beta blockers on mortality after AMI. Charts of 201,752 patients with AMI were abstracted by the Cooperative Cardiovascular Project, a quality assurance program sponsored by the Health Care Financing Administration. Of the 69,338 patients prescribed beta blockers, we compared mortality of patients receiving different beta-adrenergic blockers using the Cox proportional-hazards model accounting for multiple factors that might influence survival. The mortality rates of the 2 selective agents, metoprolol and atenolol, were virtually identical (13.5% and 13.4% 2-year mortality, respectively). Compared with metoprolol, patients discharged on propranolol had a slightly increased mortality (15.9% 2-year mortality), which may be related to undetected differences at baseline. Survival with all of the drugs was superior to the 23.9% 2-year mortality seen in patients not receiving beta blockers. Beta blockade overall was associated with a 40% improvement in survival. Although the use of beta blockade after AMI has major prognostic importance, the present study suggests that the specific beta blocker chosen will have little influence on mortality.

Are all beta-blockers the same for chronic heart failure?

beta-Adrenergic receptor blockade has been conclusively proven to increase survival and morbidity in patients with heart failure. Hospitalization rate decreases and patients feel better after receiving beta-blockers. Furthermore, this benefit is observed in a wide range of patients. The beta-blockers bisoprolol, metoprolol, and carvedilol have been extensively evaluated in heart failure patients. These drugs all show marked benefit. Bucindolol, an investigational beta-blocker, showed only mild improvement in survival in patients with heart failure. The beta-blockers differ regarding beta-selectivity, vasodilation properties, and perhaps other ancillary properties. At present, the importance and consequences of these differences are unknown.

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.

Acute hemodynamic and clinical effects of levosimendan in patients with severe heart failure. Study Investigators

BACKGROUND

We determined the short-term hemodynamic and clinical effects of levosimendan, a novel calcium-sensitizing agent, in patients with decompensated heart failure.

METHODS AND RESULTS

One hundred forty-six patients with New York Heart Association functional class III or IV heart failure (mean left ventricular ejection fraction 21+/-1%) who had a pulmonary capillary wedge pressure >/=15 mm Hg and a cardiac index </=2.5 L x min(-1) x m(-2) were enrolled in a multicenter, double-blind, placebo-controlled study and randomized 2:1 to intravenous infusion of levosimendan or placebo. Drug infusions were uptitrated over 4 hours from an initial infusion rate of 0.1 microg x kg(-1) x min(-1) to a maximum rate of 0.4 microg x kg(-1) x min(-1) and maintained at the maximal tolerated infusion rate for an additional 2 hours. Levosimendan caused dose-dependent increases in stroke volume and cardiac index beginning with the lowest infusion rate and achieving maximal increases in stroke volume and cardiac index of 28% and 39%, respectively. Heart rate increased modestly (8%) at the maximal infusion rate and was not increased at the 2 lowest infusion rates. Levosimendan caused dose-dependent decreases in pulmonary capillary wedge, right atrial, pulmonary arterial, and mean arterial pressures. Levosimendan appeared to improve dyspnea and fatigue, as assessed by the patient and physician, and was not associated with a significant increase in adverse events.

CONCLUSIONS

Levosimendan caused rapid dose-dependent improvement in hemodynamic function in patients with decompensated heart failure. These hemodynamic effects appeared to be accompanied by symptom improvement and were not associated with a significant increase in the number of adverse events. Levosimendan may be of value in the short-term management of patients with decompensated heart failure.

Acute endothelin A receptor blockade causes selective pulmonary vasodilation in patients with chronic heart failure

BACKGROUND

Elevated plasma endothelin-1 (ET-1) levels in patients with chronic heart failure correlate with pulmonary artery pressures and pulmonary vascular resistance. ET(A) receptors on vascular smooth muscle cells mediate pulmonary vascular contraction and hypertrophy. We determined the acute hemodynamic effects of sitaxsentan, a selective ET(A) receptor antagonist, in patients with chronic stable heart failure receiving conventional therapy.

METHODS AND RESULTS

This multicenter, double-blind, placebo-controlled trial enrolled 48 patients with chronic New York Heart Association functional class III or IV heart failure (mean left ventricular ejection fraction 21+/-1%) treated with ACE inhibitors and diuretics. Patients with a baseline pulmonary capillary wedge pressure >/=15 mm Hg and a cardiac index </=2.5 L. min(-1). m(-2) were randomized to 1 of 3 doses (1.5, 3.0, or 6.0 mg/kg) of sitaxsentan or placebo as an intravenous infusion over 15 minutes. Hemodynamic responses were assessed by catheterization of the right side of the heart for 6 hours. Sitaxsentan decreased pulmonary artery systolic pressure, pulmonary vascular resistance, mean pulmonary artery pressure, and right atrial pressure (P</=0.001, 0.003, 0.017, and 0.031, respectively) but had no effect on heart rate, mean arterial pressure, pulmonary capillary wedge pressure, cardiac index, or systemic vascular resistance. Plasma ET-1 levels were elevated at baseline and decreased with sitaxsentan.

CONCLUSIONS

In patients with moderate to severe heart failure receiving conventional therapy, acute ET(A) receptor blockade caused selective pulmonary vasodilation associated with a reduction in plasma ET-1. Sitaxsentan may be of value in the treatment of patients with pulmonary hypertension secondary to chronic heart failure.

The impact of beta-blockade on mortality rates in patients with congestive heart failure

The beneficial effects of beta-adrenergic blockade on mortality rates in patients after a myocardial infarction have been clear for decades. The efficacy data are now just as apparent for patients with heart failure. Although there are many subgroups of patients in whom the mortality effects of beta-blockers are not proven, knowledge about these specific populations continues to increase. Nevertheless, more information is needed so that we can properly tailor our therapy for individual patients.

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.

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.

A four-part regimen for clinical heart failure

Combination therapy with a diuretic, digoxin, ACE inhibitor, and beta-blocker can help patients with heart failure caused by severe systolic dysfunction feel better and live longer. Especially with ACE inhibitors and beta-blockers, the key to success is starting at low doses and titrating carefully to proven target doses. The demanding complexity of the four-drug regimen is well worth the results.

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.

Effect of beta-blockade on mortality among high-risk and low-risk patients after myocardial infarction

BACKGROUND

Long-term administration of beta-adrenergic blockers to patients after myocardial infarction improves survival. However, physicians are reluctant to administer beta-blockers to many patients, such as older patients and those with chronic pulmonary disease, left ventricular dysfunction, or non-Q-wave myocardial infarction.

METHODS

The medical records of 201,752 patients with myocardial infarction were abstracted by the Cooperative Cardiovascular Project, which was sponsored by the Health Care Financing Administration. Using a Cox proportional-hazards model that accounted for multiple factors that might influence survival, we compared mortality among patients treated with beta-blockers with mortality among untreated patients during the two years after myocardial infarction.

RESULTS

A total of 34 percent of the patients received beta-blockers. The percentage was lower among the very elderly, blacks, and patients with the lowest ejection fractions, heart failure, chronic obstructive pulmonary disease, elevated serum creatinine concentrations, or type 1 diabetes mellitus. Nevertheless, mortality was lower in every subgroup of patients treated with beta-blockade than in untreated patients. In patients with myocardial infarction and no other complications, treatment with beta-blockers was associated with a 40 percent reduction in mortality. Mortality was also reduced by 40 percent in patients with non-Q-wave infarction and those with chronic obstructive pulmonary disease. Blacks, patients 80 years old or older, and those with a left ventricular ejection fraction below 20 percent, serum creatinine concentration greater than 1.4 mg per deciliter (124 micromol per liter), or diabetes mellitus had a lower percentage reduction in mortality. Given, however, the higher mortality rates in these subgroups, the absolute reduction in mortality was similar to or greater than that among patients with no specific risk factors.

CONCLUSIONS

After myocardial infarction, patients with conditions that are often considered contraindications to beta-blockade (such as heart failure, pulmonary disease, and older age) and those with nontransmural infarction benefit from beta-blocker therapy.

The effects of diuresis on the pharmacokinetics of the loop diuretics furosemide and torsemide in patients with heart failure

PURPOSE

To evaluate the pharmacokinetics of furosemide and torsemide before and after diuresis in patients presenting with marked fluid overload.

SUBJECTS AND METHODS

We studied 44 patients with New York Heart Association class III or IV heart failure, ejection fraction < or =40%, and an estimated excess fluid body weight > or =6.8 kg. Oral furosemide or torsemide was administered before and after diuresis. Pharmacokinetic parameters were assessed before and after diuresis.

RESULTS

Following diuresis, maximum plasma concentration increased from 11.0+/-5.0 microg/mL to 13.9+/-6.8 with torsemide (P <0.05) and from 3.1< or =1.5 to 3.9+/-1.9 with furosemide (P=0.16). Maximum concentration increased by more than 30% in only one third of the patients. Total absorption (by area under the curve method) increased 6% among patients on torsemide (P=0.38) and 7% among patients on furosemide (P=0.63) and increased >30% in only 1 torsemide and 2 furosemide patients. The time to maximum concentration decreased from 1.40+/-.82 h to 0.81+/-0.36 with torsemide (P <0.01). There were no differences between furosemide and torsemide in the effects of edema on absorption.

CONCLUSION

Marked diuresis altered the pharmacokinetics of both furosemide and torsemide in only a small percentage of patients. The use of adequate doses of oral diuretics in edematous patients may be successful, thereby permitting home treatment with oral diuretics and avoiding the cost of hospitalizations or home intravenous administration services.

Daily energy requirements in heart failure patients

Diminished body cell mass in heart failure patients contributes to poor prognosis and decreased quality of life. The level of daily energy intake needed to maintain body cell mass and optimal physiological function in heart failure patients is unknown. Thus, we examined daily energy expenditure in free-living heart failure patients to estimate daily energy requirements. Daily energy expenditure (doubly labeled water) and its components (resting and physical activity energy expenditures) were measured in 26 heart failure patients (25 men and one woman aged 69 +/- 7 years) and 50 healthy controls (48 men and two women aged 69 +/- 6 years). Resting energy expenditure was measured by indirect calorimetry; physical activity energy expenditure from the difference between daily and resting energy expenditure; body composition by dual-energy x-ray absorptiometry; leisure time physical activity from a questionnaire; and peak oxygen consumption ([peak VO2] n = 16 heart failure patients) from a treadmill test to exhaustion. Plasma markers of nutritional status were also considered. Daily energy expenditure was 17% lower (2,110 +/- 500 v 2,543 +/- 449 kcal/d) and physical activity energy expenditure 54% lower (333 +/- 345 v 728 +/- 374 kcal/d) in heart failure patients compared with healthy controls. Daily energy expenditure was related to physical activity energy expenditure (r = .79, P < .01), resting energy expenditure (r = .63, P < .01), leisure time physical activity (r = .63, P < .01), and peak VO2 (r = .58, P < .01) in heart failure patients. Stepwise regression analysis showed that daily energy requirements in heart failure patients were best estimated by a combination of resting energy expenditure and reported leisure time physical activity (total R2 = 61%; standard error of the estimate, +/- 333 kcal/d). Daily energy requirements predicted from equations derived in healthy elderly were inaccurate when applied to heart failure patients, deviating -10% to +30% from measured daily energy expenditure. We conclude that despite low levels of activity, markers of physical activity predicted daily energy needs in heart failure patients. We provide a new equation to estimate energy needs in free-living heart failure patients based on measurements of daily energy expenditure.

Torsades de pointes with administration of high-dose intravenous d-sotalol to a patient with congestive heart failure

A patient with heart failure was administered d-sotalol 3.0 mg/kg infused over 2 minutes. The patient had normal electrolytes and baseline QT. Six minutes after drug administration the QT prolonged to 600 msec, and the patient developed torsades de pointes and required electrical cardioversion. This emphasizes the need to consider both rate of administration and the dosage when evaluating the safety and efficacy of a new class III antiarrhythmic drug.