Predictors of improvement in left ventricular ejection fraction with carvedilol for congestive heart failure

Relationship of LVEF and Myocardial Scar to Long-Term Mortality Risk and Mode of Death in Patients With Nonischemic Cardiomyopathy

BACKGROUND

Nonischemic cardiomyopathy is a leading cause of reduced left ventricular ejection fraction (LVEF) and is associated with high mortality risk from progressive heart failure and arrhythmias. Myocardial scar on cardiovascular magnetic resonance imaging is increasingly recognized as a risk marker for adverse outcomes; however, left ventricular dysfunction remains the basis for determining a patient's eligibility for primary prophylaxis with implantable cardioverter-defibrillator. We investigated the relationship of LVEF and scar with long-term mortality and mode of death in a large cohort of patients with nonischemic cardiomyopathy.

METHODS

This study is a prospective, longitudinal outcomes registry of 1020 consecutive patients with nonischemic cardiomyopathy who underwent clinical cardiovascular magnetic resonance imaging for the assessment of LVEF and scar at 3 centers.

RESULTS

During a median follow-up of 5.2 (interquartile range, 3.8, 6.6) years, 277 (27%) patients died. On survival analysis, LVEF ≤35% and scar were strongly associated with all-cause (log-rank test P=0.002 and P<0.001, respectively) and cardiac death (P=0.001 and P<0.001, respectively). Whereas scar was strongly related to sudden cardiac death (SCD; P=0.001), there was no significant association between LVEF ≤35% and SCD risk (P=0.57). On multivariable analysis including established clinical factors, LVEF and scar are independent risk markers of all-cause and cardiac death. The addition of LVEF provided incremental prognostic value but insignificant discrimination improvement by C-statistic for all-cause and cardiac death, but no incremental prognostic value for SCD. Conversely, scar extent demonstrated significant incremental prognostic value and discrimination improvement for all 3 end points. On net reclassification analysis, the addition of LVEF resulted in no significant improvement for all-cause death (11.0%; 95% CI, -6.2% to 25.9%), cardiac death (9.8%; 95% CI, -5.7% to 29.3%), or SCD (7.5%; 95% CI, -41.2% to 42.9%). Conversely, the addition of scar extent resulted in significant reclassification improvement of 25.5% (95% CI, 11.7% to 41.0%) for all-cause death, 27.0% (95% CI, 11.6% to 45.2%) for cardiac death, and 40.6% (95% CI, 10.5% to 71.8%) for SCD.

CONCLUSIONS

Myocardial scar and LVEF are both risk markers for all-cause and cardiac death in patients with nonischemic cardiomyopathy. However, whereas myocardial scar has strong and incremental prognostic value for SCD risk stratification, LVEF has no incremental prognostic value over clinical measures. Scar assessment should be incorporated into patient selection criteria for primary prevention implantable cardioverter-defibrillator placement.

Progression of Myocardial Fibrosis in Nonischemic DCM and Association With Mortality and Heart Failure Outcomes

OBJECTIVES

The purpose of this study was to assess whether the presence and extent of fibrosis changes over time in patients with nonischemic, dilated cardiomyopathy (DCM) receiving optimal medical therapy and the implications of any such changes on left ventricular ejection fraction (LVEF) and clinical outcomes.

BACKGROUND

Myocardial fibrosis on cardiovascular magnetic resonance (CMR) imaging has emerged as important risk marker in patients with DCM.

METHODS

In total, 85 patients (age 56 ± 15 years, 45% women) with DCM underwent serial CMR (median interval 1.5 years) for assessment of LVEF and fibrosis. The primary outcome was all-cause mortality; the secondary outcome was a composite of heart failure hospitalization, aborted sudden cardiac death, left ventricular (LV) assist device implantation, or heart transplant.

RESULTS

On CMR-1, fibrosis (median 0.0 [interquartile range: 0% to 2.6%]) of LV mass was noted in 34 (40%) patients. On CMR-2, regression of fibrosis was not seen in any patient. Fibrosis findings were stable in 70 (82%) patients. Fibrosis progression (increase >1.8% of LV mass or new fibrosis) was seen in 15 patients (18%); 46% of these patients had no fibrosis on CMR-1. Although fibrosis progression was on aggregate associated with adverse LV remodeling and decreasing LVEF (40 ± 7% to 34 ± 10%; p < 0.01), in 60% of these cases the change in LVEF was minimal (<5%). Fibrosis progression was associated with increased hazards for all-cause mortality (hazard ratio: 3.4 [95% confidence interval: 1.5 to 7.9]; p < 0.01) and heart failure-related complications (hazard ratio: 3.5 [95% confidence interval: 1.5 to 8.1]; p < 0.01) after adjustment for clinical covariates including LVEF.

CONCLUSIONS

Once myocardial replacement fibrosis in DCM is present on CMR, it does not regress in size or resolve over time. Progressive fibrosis is often associated with minimal change in LVEF and identifies a high-risk cohort.

Effects of carvedilol on structural and functional outcomes and plasma biomarkers in the mouse transverse aortic constriction heart failure model

INTRODUCTION

Despite the widespread use of the mouse transverse aortic constriction heart failure model, there are no reports on the characterization of the standard-of-care agent carvedilol in this model.

METHODS

Left ventricular pressure overload was produced in mice by transverse aortic constriction between the innominate and left common carotid arteries. Carvedilol was administered at multiple dose levels (3, 10 and 30 mg/kg/day per os; yielding end-study mean plasma concentrations of 0.002, 0.015 and 0.044 µM, respectively) in a therapeutic design protocol with treatment initiated after the manifestation of left ventricular remodeling at 3 weeks post transverse aortic constriction and continued for 10 weeks.

RESULTS

Carvedilol treatment in transverse aortic constriction mice significantly decreased heart rate and left ventricular dP/dt (max) at all dose levels consistent with β-adrenoceptor blockade. The middle dose of carvedilol significantly decreased left ventricular weight, whereas the higher dose decreased total heart, left and right ventricular weight and wet lung weight compared to untreated transverse aortic constriction mice. The higher dose of carvedilol significantly increased cardiac performance as measured by ejection fraction and fractional shortening and decreased left ventricular end systolic volume consistent with the beneficial effect on cardiac function. End-study plasma sST-2 and Gal-3 levels did not differ among sham, transverse aortic constriction control and transverse aortic constriction carvedilol groups. Plasma brain natriuretic peptide concentrations were elevated significantly in transverse aortic constriction control animals (~150%) compared to shams in association with changes in ejection fraction and heart weight and tended to decrease (~30%, p = 0.10-0.12) with the mid- and high-dose carvedilol treatment.

CONCLUSION

A comparison of carvedilol hemodynamic and structural effects in the mouse transverse aortic constriction model versus clinical use indicates a strong agreement in effect profiles preclinical versus clinical, providing important translational validation for this widely used animal model. The present plasma brain natriuretic peptide biomarker findings support the measurement of plasma natriuretic peptides in the mouse transverse aortic constriction model to extend the translational utility of the model.

Carvedilol Improves Myocardial Contractility Compared With Metoprolol in Patients With Chronic Hibernating Myocardium After Revascularization

Background: We tested the hypothesis of whether carvedilol delays morphologic degeneration and improves functional outcome compared with metoprolol tartrate in patients with hibernating myocardium undergoing surgical revascularization. We have previously shown that patients with chronic hibernating myocardium undergo progressive cellular degeneration and fibrosis.

Methods: Twenty patients with multivessel coronary artery disease revascularization and hibernating myocardium as assessed by technetium-99m perfusion scintigraphy and fluorine-18-fluorodeoxyglucose positron emission tomography were randomized to receive either carvedilol or metoprolol tartrate for at least 2 months before surgery, and this was continued for 7 months postoperatively. Left ventricular ejection fraction and regional wall motion abnormalities were assessed by left ventriculography at baseline and 7 months postoperatively. Intraoperative transmural needle biopsy samples were obtained for microscopic analysis.

Results: Postoperatively, the ejection fraction increased from 31% ± 5% to 44% ± 4% ( P < .005) in the carvedilol group (n = 10), and from 30% ± 6% to 40% ± 6% in the metoprolol tartrate group ( P < .05 vs preoperatively and vs carvedilol). Wall motion abnormalities in the carvedilol group improved from -2.1 ± 0.4 to -0.6 ± 0.5 ( P < .05) and from -2.3 ± 0.5 to -1.6 ± 0.6 in the metoprolol tartrate group ( P < .05 vs preoperatively and vs carvedilol). Microscopic analysis after 72 ± 18 days of either treatment showed mild cardiomyocyte degeneration and moderate-to-severe fibrosis (28% ± 7%) in the carvedilol group compared with moderate cardiomyocyte degeneration and moderate-to-severe fibrosis (33% ± 6%) in the metoprolol tartrate group. Apoptosis, as assessed by the terminal deoxynucleotidyl transferase nick end labeling method, was observed in only 1 patient in each group.

Conclusions: Carvedilol treatment of hibernating myocardium results in improved functional recovery after revascularization compared with metoprolol tartrate, and this might partially be related to reduced cardiomyocyte degeneration.

A low-dose β1-blocker effectively and safely slows the heart rate in patients with acute decompensated heart failure and rapid atrial fibrillation

OBJECTIVE

Recently, we reported that low-dose landiolol (1.5 µg·kg(-1)·min(-1)), an ultra-short-acting β-blocker, safely decreased the heart rate (HR) in patients with acute decompensated heart failure (ADHF) and sinus tachycardia, thereby improving cardiac function. We investigated whether low-dose landiolol effectively decreased the HR in ADHF patients with rapid atrial fibrillation (AF).

METHODS

We enrolled 23 ADHF patients with rapid AF (HR ≥120 beats·min(-1) and New York Heart Association class III-IV) and systolic heart failure (SHF: n = 12) or diastolic heart failure (DHF: n = 11) who received conventional therapy with diuretics, vasodilators, and/or low-dose inotropes. They were administered continuous intravenous infusion of low-dose landiolol (1.0-2.0 µg·kg(-1)·min(-1)), and their electrocardiograms and blood pressures were monitored for 24 h thereafter.

RESULTS

Two hours after starting landiolol, the HR was reduced significantly (22%), without a reduction in blood pressure, and remained constant thereafter. The HR reduction 2 h after landiolol administration was significantly greater in the DHF group than in the SHF group. No incidence of hypotension was recorded.

CONCLUSIONS

Digitalis or amiodarone is currently recommended for HR control in ADHF patients with rapid AF. Our results showed that continuous infusion of low-dose landiolol may also be useful as first-line therapy in these patients.

Similar patterns of myocardial metabolism and perfusion in patients with type 2 diabetes and heart disease of ischaemic and non-ischaemic origin

AIMS/HYPOTHESIS

Type 2 diabetes and insulin resistance are often associated with the co-occurrence of coronary atherosclerosis and cardiac dysfunction. The aim of this study was to define the independent relationships between left ventricular dysfunction or ischaemia and patterns of myocardial perfusion and metabolism in type 2 diabetes.

METHODS

Twenty-four type 2 diabetic patients--12 with coronary artery disease (CAD) and preserved left ventricular function and 12 with non-ischaemic heart failure (HF)--were enrolled in a cross-sectional study. Positron emission tomography (PET) was used to assess myocardial blood flow (MBF) at rest, after pharmacological stress and under euglycaemic hyperinsulinaemia. Insulin-mediated myocardial glucose disposal was determined with 2-deoxy-2-[(18)F]fluoroglucose PET.

RESULTS

There was no difference in myocardial glucose uptake (MGU) between the healthy myocardium of CAD patients and the dysfunctional myocardium of HF patients. MGU was strongly influenced by levels of systemic insulin resistance in both groups (CAD, r = 0.85, p = 0.005; HF, r = 0.77, p = 0.01). In HF patients, there was an inverse association between MGU and the coronary flow reserve (r = -0.434, p = 0.0115). A similar relationship was observed in non-ischaemic segments of CAD patients. Hyperinsulinaemia increased MBF to a similar extent in the non-ischaemic myocardial of CAD and HF patients.

CONCLUSIONS/INTERPRETATION

In type 2 diabetes, similar metabolic and perfusion patterns can be detected in the non-ischaemic regions of CAD patients with normal cardiac function and in the dysfunctional non-ischaemic myocardium of HF patients. This suggests that insulin resistance, rather than diagnosis of ischaemia or left ventricular dysfunction, affects the metabolism and perfusion features of patients with type 2 diabetes.

Cardiac remodeling with rhythm versus rate control strategies for atrial fibrillation in patients with heart failure: insights from the AF-CHF echocardiographic sub-study

BACKGROUND

In patients with heart failure and atrial fibrillation, the AF-CHF (Atrial Fibrillation and Congestive Heart Failure) trial did not demonstrate the superiority of rhythm control (RhyC) over a rate control (RaC) strategy on cardiovascular mortality. Nevertheless, deleterious hemodynamic effects of atrial fibrillation can lead to further decrease in left ventricular (LV) function and progression of symptoms. This echocardiographic sub-study was designed to compare the effects of the two treatment strategies on LV ejection fraction (LVEF), chamber volumes and dimensions, valvular regurgitation and functional status.

METHODS AND RESULTS

A total of 59 patients (29 RhyC, 30 RaC) aged 67±8 years (14% women), enrolled in the AF-CHF trial at the Montreal Heart Institute underwent standardized echocardiograms at baseline and at 12 months. Mean LVEF at baseline was severely depressed (RhyC: 27.0±4.9% and RaC: 27.6±7.4%, p=0.73), and improved to a similar degree in both groups (RhyC: +8.0±10.4% and RaC: +4.5±10.6, both p<0.05; p=0.19 for RhyC versus RaC). Other echocardiographic parameters, such as LV end-systolic volume index and degree of mitral and tricuspid regurgitation, remained unchanged. New York Heart Association functional class and distance walked in 6 min improved significantly in both groups (RhyC: +48.9±78.7 m and RaC: +47.2±96.7 m, both p≤0.01), with no difference between RhyC and RaC strategies.

CONCLUSIONS

Improvements in LVEF and functional status are observed after 12 months in patients with heart failure and atrial fibrillation, regardless of whether rate or rhythm control strategies are used.

Relation between regional and global systolic function in patients with ischemic cardiomyopathy after beta-blocker therapy or revascularization

BACKGROUND

To assess the relationship between improved regional and global myocardial function in patients with ischemic cardiomyopathy in response to beta-blocker therapy or revascularization.

MATERIALS AND METHODS

Cardiovascular magnetic resonance (CMR) was performed in 32 patients with ischemic cardiomyopathy before and 8 +/- 2 months after therapy. Patients were assigned clinically to beta-blocker therapy (n = 20) or revascularization (n = 12). CMR at baseline was performed to assess regional and global LV function at rest and under low-dose dobutamine. Wall thickening was analyzed in dysfunctional, adjacent, and remote segments. Follow-up CMR included rest function evaluation.

RESULTS

Augmentation of wall thickening during dobutamine at baseline was similar in dysfunctional, adjacent and remote segments in both patient groups. Therefore, baseline characteristics were similar for both patient groups. In both patient groups resting LV ejection fraction and end-systolic volume improved significantly (p < 0.05) at follow-up. Stepwise multivariate analysis revealed that improvement in global LV ejection fraction in the beta-blocker treated patients was significantly related to improved function of remote myocardium (p < 0.05), whereas in the revascularized patients improved function in dysfunctional and adjacent segments was more pronounced (p < 0.05).

CONCLUSION

In patients with chronic ischemic LV dysfunction, beta-Blocker therapy or revascularization resulted in a similar improvement of global systolic LV function. However, after beta-blocker therapy, improved global systolic function was mainly related to improved contraction of remote myocardium, whereas after revascularization the dysfunctional and adjacent regions contributed predominantly to the improved global systolic function.

Insulin-resistant cardiomyopathy clinical evidence, mechanisms, and treatment options

Increasing evidence points to insulin resistance as a primary etiologic factor in the development of nonischemic heart failure (HF). The myocardium normally responds to injury by altering substrate metabolism to increase energy efficiency. Insulin resistance prevents this adaptive response and can lead to further injury by contributing to lipotoxicity, sympathetic up-regulation, inflammation, oxidative stress, and fibrosis. Animal models have repeatedly demonstrated the existence of an insulin-resistant cardiomyopathy, one that is characterized by inefficient energy metabolism and is reversible by improving energy use. Clinical studies in humans strongly support the link between insulin resistance and nonischemic HF. Insulin resistance is highly prevalent in the nonischemic HF population, predates the development of HF, independently defines a worse prognosis, and predicts response to antiadrenergic therapy. Potential options for treatment include metabolic-modulating agents and antidiabetic drugs. This article reviews the basic science evidence, animal experiments, and human clinical data supporting the existence of an "insulin-resistant cardiomyopathy" and proposes specific potential therapeutic approaches.

HUMAN HEART ?-ADRENOCEPTORS: ?1-ADRENOCEPTOR DIVERSIFICATION THROUGH ?AFFINITY STATES? AND POLYMORPHISM

1. In atrium and ventricle from failing and non-failing human hearts, activation of beta(1)- or beta(2)-adrenoceptors causes increases in contractile force, hastening of relaxation, protein kinase A-catalysed phosphorylation of proteins implicated in the hastening of relaxation, phospholamban, troponin I and C-protein, consistent with coupling of both beta(1)- and beta(2)-adrenoceptors to stimulatory G(salpha)-protein but not inhibitory G(ialpha)-protein. 2. Two 'affinity states', namely beta(1H) and beta(1L), of the beta(1)-adrenoceptor exist. In human heart, noradrenaline elicits powerful increases in contractile force and hastening of relaxation. These effects are blocked with high affinity by beta-adenoceptor antagonists, including propranolol, (-)-pindolol, (-)-CGP 12177 and carvedilol. Some beta-blockers, typified by (-)-pindolol and (-)-CGP 12177, not only block the receptor, but also activate it, albeit at much higher concentrations (approximately 2 log units) than those required to antagonize the effects of catecholamines. In human heart, both (-)-CGP 12177 and (-)-pindolol increase contractile force and hasten relaxation. However, the involvement of the beta(1)-adrenoceptor was not immediately obvious because (-)-pindolol- and (-)-CGP 12177-evoked responses were relatively resistant to blockade by (-)-propranolol. Abrogation of cardiostimulant effects of (-)-CGP 12177 in beta(1)-/beta(2)-adrenoceptor double-knockout mice, but not beta(2)-adrenoceptor-knockout mice, revealed an obligatory role of the beta(1)-adrenoceptor. On the basis of these results, two 'affinity states' have been designated, the beta(1H)- and beta(1L)-adrenoceptor, where the beta(1H)-adrenoceptor is activated by noradrenaline and blocked with high affinity by beta-blockers and the beta(1L)-adrenoceptor is activated by drugs such as (-)-CGP 12177 and (-)-pindolol and blocked with low affinity by beta-blockers such as (-)-propranolol. The beta(1H)- and beta(1L)-adrenoceptor states are consistent with high- and low-affinity binding sites for (-)-[(3)H]-CGP 12177 radioligand binding found in cardiac muscle and recombinant beta(1)-adrenoceptors. 3. There are two common polymorphic locations of the beta(1)-adrenoceptor, at amino acids 49 (Ser/Gly) and 389 (Arg/Gly). Their existence has raised several questions, including their role in determining the effectiveness of heart failure treatment with beta-blockers. We have investigated the effect of long-term maximally tolerated carvedilol administration (> 1 year) on left ventricular ejection fraction (LVEF) in patients with non-ischaemic cardiomyopathy (mean left ventricular ejection fraction 23 +/- 7%; n = 135 patients). The administration of carvedilol improved LVEF to 37 +/- 13% (P < 0.005); however, the improvement was variable, with 32% of patients showing pound 5% improvement. Upon segregation of patients into Arg389Gly-beta(1)-adrenoceptors, it was found that carvedilol caused a greater increase in left ventricular ejection faction in patients carrying the Arg389 allele with Arg389Arg > Arg389Gly > Gly389Gly.

Improvement of cardiac function persists long term with medical therapy for left ventricular systolic dysfunction

In certain patients with left ventricular (LV) systolic dysfunction, improvements in cardiac function are seen after initiation of medical therapy; however, the long-term stability of ventricular function in such patients is not well described. We retrospectively analyzed 171 patients who had a baseline ejection fraction of 45% or less, a follow-up echocardiogram at 2 to 12 months after initiation of medical therapy, and a final echocardiogram. We found that 48.5% of the patients demonstrated initial improvements in LV function after initiation of medical therapy, and the improvements appear to be sustained (88% of patients) at 44 +/- 21 months follow-up. A nonischemic etiology and younger age were the only independent predictors of change of LV ejection fraction of 10 or more at a mean 8.4 +/- 3.4 months after optimal medical therapy. Our study revealed a trend toward improved long-term survival in individuals with an early improvement in LV ejection fraction with medical therapy, especially in those with sustained improvement.

The effects of beta-blockers in patients with stable chronic heart failure. Predictors of left ventricular ejection fraction improvement and impact on prognosis

BACKGROUND

Previous studies, with limited number of patients, have tried to determine the predictors of left ventricular ejection fraction (LVEF) improvement after beta-blockade. No study has demonstrated that LVEF improvement was an independent predictor of cardiac survival.

METHODS

The aims of the study were to determine in a large group of patients with stable chronic heart failure associated with reduced LVEF the predictors of LVEF improvement (difference in LVEF [deltaLVEF], ie, the value after beta-blockade minus the value before beta-blockade) after beta-blockade and to analyze prognostic impact of deltaLVEF. Three hundred fourteen consecutive patients underwent an echocardiogram, a radionuclide angiogram, and a maximum cardiopulmonary exercise test before and 3 months after maximal tolerated doses of beta-blockers have been reached.

RESULTS

After beta-blockade, LVEF improved from 30% +/- 11% to 40% +/- 13%. In the whole population, independent predictors of deltaLVEF were nonischemic etiology, baseline LVEF (negative correlation), and baseline heart rate (positive correlation). In ischemic patients, independent predictors of deltaLVEF were absence of history of myocardial infarction, baseline heart rate, and baseline LVEF; whereas in nonischemic patients, independent predictors were baseline LVEF and baseline QRS width (negative correlation). After 1082 days of follow-up, there were 53 cardiovascular deaths and 2 urgent transplantations. Left ventricular ejection fraction improvement (defined as an absolute increase in LVEF > 5%) was an independent predictor of cardiac survival. Patients who had an LVEF < or = 45% after beta-blockade with a deltaLVEF < or = 5% represented a high-risk subgroup.

CONCLUSIONS

In patients with chronic heart failure, predictors of LVEF improvement after beta-blockade were different according to etiology. Left ventricular ejection fraction improvement was an independent predictor of cardiac survival.

Predictors of Therapeutic Response to Beta-blockers in Patients with Heart Failure in Taiwan

BACKGROUND/PURPOSE

Chinese are more sensitive to beta-blockers than Caucasians. However, data regarding beta-blocker therapy in heart failure (HF) patients in Taiwan are lacking. We aimed to evaluate the improvement of left ventricular function and the potential predictors of response to beta-blocker therapy in Taiwanese HF patients.

METHODS

We enrolled 34 HF patients with baseline left ventricular ejection fraction (LVEF) </= 40%. Beta-blockers were titrated up to the maximum tolerable dose. LVEF prior to beta-blocker usage and at the stable dose were obtained. We also sequenced the entire gene encoding beta1-adrenoceptor to assess the relationships between LVEF improvement and gene polymorphisms.

RESULTS

Beta-blocker therapy (25 +/- 22 months) with a mean stable dose of 12 +/- 8 mg carvedilol/day significantly improved LVEF (from 28 +/- 8% to 40 +/- 15%, p < 0.001). Stepwise multiple linear regression analysis identified dilated cardiomyopathy (beta = 18.32, p = 0.0004), baseline LVEF (beta = -0.85, p = 0.0020), use of amiodarone (beta = -22.58, p = 0.0034) and square of digoxin dose (beta = -314.25, p = 0.0059) at stable beta-blocker dose as independent predictors of LVEF improvement, where beta is the estimated regression coefficient. We did not find any novel variant of beta1-adrenoceptor gene other than those previously reported at codons 49 and 389, with the allele distributions similar to those found in Caucasians, and these polymorphisms did not imply therapeutic response to beta-blocker.

CONCLUSION

We demonstrated the therapeutic effects of beta-blockers in Taiwanese HF patients with a dose lower than what has been reported in Western people. Moreover, patients with the etiology of dilated cardiomyopathy or lower baseline LVEF predicted a greater LVEF improvement. The beta1-adrenoceptor gene polymorphisms were not responsible for the difference in sensitivity to beta-blockers in this Taiwanese population.

Effects of long-term treatment with carvedilol on myocardial blood flow in idiopathic dilated cardiomyopathy

OBJECTIVE

To assess whether chronic treatment with carvedilol can increase myocardial blood flow (MBF) and MBF reserve in idiopathic dilated cardiomyopathy (IDC).

STUDY DESIGN

In a double-blind, placebo-controlled trial, 16 consecutive patients with IDC were randomised to treatment with either carvedilol up to 25 mg twice a day (n = 8, 7 men, mean (SD) age 60 (9) years, mean (SD) left ventricular ejection fraction (LVEF) 30% (5%)), or placebo (n = 8, 6 men, mean (SD) age 62 (9) years, mean (SD) LVEF 28% (6%), NS vs carvedilol group). Before and 6 months after treatment, regional MBF was measured at rest and after intravenous injection of dipyridamole (Dip; 0.56 mg/kg in 4 min) by positron emission tomography and using (13)N-ammonia as a flow tracer. Exercise capacity was assessed as the time duration in a maximal bicycle exercise stress test.

RESULTS

Carvedilol induced a significant decrease in heart rate at rest and during maximal exercise, and an increase in exercise capacity. Absolute MBF values did not significantly change after carvedilol or placebo treatment, either at rest or during Dip injection, although Dip-MBF tended to improve after treatment. Coronary flow reserve significantly increased following carvedilol treatment (from 1.67 (0.63) to 2.58 (1.04), p<0.001), whereas it remained unchanged following the placebo treatment (from 1.80 (0.84) to 1.77 (0.60), NS). Stress-induced regional perfusion defects decreased after carvedilol treatment (from 38% to 15%).

CONCLUSIONS

Long-term treatment with carvedilol can significantly increase coronary flow reserve and reduce the occurrence of stress-induced perfusion defects, suggesting a favourable effect of the drug on coronary microvascular function in patients with IDC.

Antiarrhythmic Mechanisms of n-3 PUFA and the Results of the GISSI-Prevenzione Trial

The purpose of this paper is twofold: on the one hand, to confirm the positive results on n-3 PUFA from the overall results Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GlSSI)-Prevenzione trial; on the other, to summarize and describe how the results of an important trial can help generate hypotheses either on mechanisms of action or on differential results in particular subgroups of patients, as well as test the pathophysiological hypotheses that have accompanied in the years the story of the hypothesized mechanisms of action of a drug. GISSI-Prevenzione was conceived as a pragmatic population trial on patients with recent myocardial infarction and it was conducted in the framework of the Italian public health system. In GISSI-Prevenzione, 11,323 patients were enrolled in a clinical trial aimed at testing the effectiveness of n-3 polyunsaturated fatty acids (PUFA) and vitamin E. Patients were invited to follow Mediterranean dietary habits, and were treated with up-to-date preventive pharmacological interventions. Long-term n-3 PUFA at 1 g daily, but not vitamin E at 300 mg daily, was beneficial for death and for combined death, non-fatal myocardial infarction, and stroke. All the benefit, however, was attributable to the decrease in risk for overall (-20%), cardiovascular (-30%), and sudden death (-45%). At variance from the orientation of a scientific scenario largely dominated by the "cholesterol-heart hypothesis", GISSI-Prevenzione results indicate n-3 PUFA (virtually devoid of any cholesterol-lowering effect) as a relevant pharmacological treatment for secondary prevention after myocardial infarction.

Effect of chronic right ventricular apical pacing on left ventricular function

The determinants of change in left ventricular (LV) ejection fraction (EF) over time in patients with impaired LV function at baseline have not been clearly established. Using a nuclear database to assess changes in LV function over time, we included patients with a baseline LVEF of 25% to 40% on a gated single-photon emission computed tomographic study at rest and only if second-gated photon emission computed tomography performed approximately 18 months after the initial study showed an improvement in LVEF at rest of > or =10 points or a decrease in LVEF at rest of > or =7 points. In all, 148 patients qualified for the EF increase group and 59 patients for the EF decrease group. LVEF on average increased from 33 +/- 4% to 51 +/- 8% in the EF increase group and decreased from 35 +/- 4% to 25 +/- 5% in the EF decrease group. The strongest multivariable predictor of improvement of LVEF was beta-blocker therapy (odds ratio 3.9, p = 0.002). The strongest independent predictor of LVEF decrease was the presence of a permanent right ventricular apical pacemaker (odds ratio 6.6, p = 0.002). Thus, this study identified beta-blocker therapy as the major independent predictor for improvement in LVEF of > or =10 points, whereas a permanent pacemaker (right ventricular apical pacing) was the strongest predictor of a LVEF decrease of > or =7 points.

Chronic left ventricular failure in the community: Prevalence, prognosis, and predictors of the complete clinical recovery with return of cardiac size and function to normal in patients undergoing optimal therapy

BACKGROUND

Chronic heart failure (CHF) is a progressive process requiring complex therapeutic interventions. Recently, several trials documented the clinical improvement and regression of left ventricular (LV) remodeling and function in patients on optimized CHF treatment. Furthermore, some authors reported isolated cases of patients who apparently "healed" from CHF. The aim of the present study was to characterize the phenomenon of the normalization in clinical status and LV size and function in CHF patients.

METHODS AND RESULTS

We monitored the clinical and echocardiographic parameters of a large cohort of patients with CHF and LV ejection fraction <40% every 6 months for a mean period of 17 +/- 9 months. Twenty of 110 study patients (18%) normalized clinical status and LV size and ejection fraction at any time (mean time 13 +/- 6 months) during the follow up. Such condition, however, was subsequently lost in 11 patients. The normalization was predicted by the nonischemic etiology of CHF, arterial hypertension, absence of diabetes mellitus, carvedilol therapy, and the dose of carvedilol.

CONCLUSIONS

The normalization in clinical status and LV size and function is not infrequently observed in patients on optimal CHF therapy. It is predicted by a set of clinical variables and favored by beta-blocker therapy. At medium term, this condition fades in a significant portion of patients.

Prevalence, predictors, and prognostic implications of improvement in left ventricular systolic function and clinical status in patients >70 years of age with recently diagnosed systolic heart failure

In recent years, several clinical trials conducted on selected middle-aged patients have documented the positive effects of new pharmacologic and nonpharmacologic treatment on chronic heart failure (HF). More recently, some investigators reported cases of elderly patients who had improved clinical conditions and left ventricular (LV) systolic function, but neither the prevalence nor the clinical variables associated with this phenomenon have ever been characterized in this population. To assess the prevalence and the predictors of "improvement" of HF, we prospectively analyzed 87 patients with a recent diagnosis of HF and LV systolic dysfunction, aged >70 years, who were consecutively admitted to our center for functional class impairment (New York Heart Association class III and IV). After discharge, patients underwent clinical and echocardiographic evaluations every 6 months. During follow-up (17 +/- 9 months) improvement was documented in 31 subjects (36%). The variables associated with improvement in the multivariate analysis were the absence of diabetes (odds ratio [OR] 5.1, 95% confidence interval [CI] 1.3 to 19.9, p = 0.007), history of arterial hypertension (OR 3.9, CI 1.3 to 11.1, p = 0.01), and beta-blocker therapy (OR 3.4, CI 1.1 to 10.8, p = 0.03). An improvement in clinical status and LV systolic function is not infrequently observed in patients >70 years of age who have a recent diagnosis of HF. This behavior occurs prevalently in patients receiving beta-blocker therapy who have a history of arterial hypertension, and is inversely related to the presence of diabetes mellitus.

Myocardial viability as a determinant of the ejection fraction response to carvedilol in patients with heart failure (CHRISTMAS trial): randomised controlled trial

BACKGROUND

The improvement in left-ventricular ejection fraction (LVEF) in response to beta blockers is heterogeneous in patients with heart failure due to ischaemic heart disease, possibly indicating variations in the myocardial substrate underlying left-ventricular dysfunction. We investigated whether improvement in LVEF was associated with the volume of hibernating myocardium (viable myocardium with contractile failure).

METHODS

We did a double-blind, randomised trial to compare placebo and carvedilol for 6 months in individuals with stable, chronic heart failure due to ischaemic left-ventricular systolic dysfunction. We enrolled 489 patients, of whom 387 were randomised. Patients were designated hibernators or non-hibernators according to the volume of hibernating myocardium. The primary endpoint was change in LVEF, measured by radionuclide ventriculography, in hibernators versus non-hibernators, on carvedilol compared with placebo. Analysis was by intention to treat.

RESULTS

82 patients dropped out of the study because of adverse events, withdrawal of consent, or failure to complete the investigation. Thus, 305 (79%) were analysed. LVEF was unchanged with placebo (mean change -0.4 [SE 0.9] and -0.4 [0.8] for non-hibernators and hibernators, respectively) but increased with carvedilol (2.5 [0.9] and 3.2 [0.8], respectively; p<0.0001 compared with baseline). Mean placebo-subtracted change in LVEF was 3.2% (95% CI 1.8-4.7; p=0.0001) overall, and 2.9% (0.7-5.1; p=0.011) and 3.6% (1.7-5.4; p=0.0002) in non-hibernators and hibernators, respectively. Effect of hibernator status on response of LVEF to carvedilol was not significant (0.7 [-2.2 to 3.5]; p=0.644). However, patients with more myocardium affected by hibernation or by hibernation and ischaemia had a greater increase in LVEF on carvedilol (p=0.0002 and p=0.009, respectively).

INTERPRETATION

Some of the effect of carvedilol on LVEF might be mediated by improved function of hibernating or ischaemic myocardium, or both. Medical treatment might be an important adjunct or alternative to revascularisation for patients with hibernating myocardium.

Beta-blockers for heart failure: why, which, when, and where

Beta-blockers are a highly effective treatment for patients with all grades of heart failure secondary to LV systolic dysfunction. Beta-blockers are best deployed as a form of tertiary prevention in heart failure but have a very limited role for the treatment of a heart failure crisis. Physicians and patients need to understand the time course of the effects of beta-blocker therapy. The initial effects are often neutral or adverse, though the benefits, at least of carvedilol, may be apparent within days in patients with severe heart failure. Benefits accumulate gradually over a period of weeks to months. Some patience, perseverance, and education are required in order to allow patients to reap the full benefits of beta-blocker therapy for this malignant disease. Initiation of treatment early in the course of the disease maximizes the effectiveness and acceptance of therapy. Trials are under way to determine whether the benefits of beta-blockers extend to patients over 80 years of age and to those with preserved LV systolic function. It is likely that important differences exist between beta-blockers in terms of their clinical benefit, though whether differences exist between the agents that have been reported to be effective so far awaits the outcome of a large clinical trial. It is unclear whether the target doses of beta-blockers currently recommended are optimal.

Continuous ambulatory right heart pressure measurements with an implantable hemodynamic monitor: a multicenter, 12-month follow-up study of patients with chronic heart failure

BACKGROUND

We describe the performance of an implantable hemodynamic monitor (IHM) that allows continuous recording of heart rate, patient activity levels, and right ventricular systolic, right ventricular diastolic, and estimated pulmonary artery diastolic pressures. Pressure parameters derived from the implantable monitor were correlated to measurements made with a balloon-tipped catheter to establish accuracy and reproducibility over time in patients with chronic heart failure (CHF).

METHODS AND RESULTS

IHM devices were implanted in 32 patients with CHF (left ventricular ejection fraction, 29% +/- 11%; range, 14%-62%) and were tested with right heart catheterization at implantation and 3, 6, and 12 months later. Hemodynamic variables were digitally recorded simultaneously from the IHM and catheter. Values were recorded during supine rest, peak response of Valsalva maneuver, sitting, peak of a 2-stage (25-50 W) bicycle exercise test, and final rest period. The median of 21 paired beat-to-beat cardiac cycles was analyzed for each intervention. A total of 217 paired data values from all maneuvers were analyzed for 32 patients at implantation and 129 paired data values for 20 patients at 1 year. The IHM and catheter values were not different at baseline or at 1 year (P >.05). Combining all interventions, correlation coefficients were 0.96 and 0.94 for right ventricular systolic pressure, 0.96 and 0.83 for right ventricular diastolic pressure, and 0.87 and 0.87 for estimated pulmonary artery diastolic pressure at implantation and 1 year, respectively.

CONCLUSIONS

The IHM and a standard reference pressure system recorded comparable right heart pressure values in patients with CHF. This implantable pressure transducer is accurate over time and provides a means to precisely monitor the hemodynamic condition of patients with CHF in a continuous fashion.

Autonomic tone as a cardiovascular risk factor: the dangers of chronic fight or flight

Chronic imbalance of the autonomic nervous system is a prevalent and potent risk factor for adverse cardiovascular events, including mortality. Although not widely recognized by clinicians, this risk factor is easily assessed by measures such as resting and peak exercise heart rate, heart rate recovery after exercise, and heart rate variability. Any factor that leads to inappropriate activation of the sympathetic nervous system can be expected to have an adverse effect on these measures and thus on patient outcomes, while any factor that augments vagal tone tends to improve outcomes. Insulin resistance, sympathomimetic medications, and negative psychosocial factors all have the potential to affect autonomic function adversely and thus cardiovascular prognosis. Congestive heart failure and hypertension also provide important lessons about the adverse effects of sympathetic predominance, as well as illustrate the benefits of beta-blockers and angiotensin-converting enzyme inhibitors, 2 classes of drugs that reduce adrenergic tone. Other interventions, such as exercise, improve cardiovascular outcomes partially by increasing vagal activity and attenuating sympathetic hyperactivity.

What is the optimal medical management of ischaemic heart failure?

Ischaemic heart disease is probably the most important cause of heart failure. All patients with heart failure may benefit from treatment designed to retard progressive ventricular dysfunction and arrhythmias. Patients with heart failure due to ischaemic heart disease may also, theoretically, benefit from treatments designed to relieve ischaemia and prevent coronary occlusion and from revascularisation. However, there is little evidence to show that effective treatments, such as angiotensin converting enzyme (ACE) inhibitors and beta-blockers, exert different effects in patients with heart failure with or without coronary disease. Moreover, there is no evidence that treatment directed specifically at myocardial ischaemia, whether or not symptomatic, or coronary disease alters outcome in patients with heart failure. Some agents, such as aspirin, designed to reduce the risk of coronary occlusion appear ineffective or harmful in patients with heart failure. There is no evidence, yet, that revascularisation improves prognosis in patients with heart failure, even in patients who are demonstrated to have extensive myocardial hibernation. On current evidence, revascularisation should be reserved for the relief of angina. Large-scale, randomised controlled trials are currently underway investigating the role of specific treatments targeted at coronary syndromes in patients who have heart failure. The CHRISTMAS study is investigating the effects of carvedilol in a large cohort of patients with and without hibernating myocardium. The WATCH study is comparing the efficacy of aspirin, clopidogrel and warfarin. The HEART-UK study is assessing the effect of revascularisation on mortality in patients with heart failure and myocardial hibernation. Smaller scale studies are currently assessing the safety and efficacy of statin therapy in patients with heart failure. Only when the results of these and other studies are known will it be possible to come to firm conclusions about whether patients with heart failure and coronary disease should be treated differently from other patients with heart failure due to left ventricular systolic dysfunction.

The effects of beta(1)-blockade on oxidative metabolism and the metabolic cost of ventricular work in patients with left ventricular dysfunction: A double-blind, placebo-controlled, positron-emission tomography study

BACKGROUND

The mechanism for the beneficial effect of beta-blocker therapy in patients with left ventricular (LV) dysfunction is unclear, but it may relate to an energy-sparing effect that results in improved cardiac efficiency. C-11 acetate kinetics, measured using positron-emission tomography (PET), are a proven noninvasive marker of oxidative metabolism and myocardial oxygen consumption (MVO(2)). This approach can be used to measure the work-metabolic index, which is a noninvasive estimate of cardiac efficiency.

METHODS AND RESULTS

The aim of this study was to determine the effect of metoprolol on oxidative metabolism and the work-metabolic index in patients with LV dysfunction. Forty patients (29 with ischemic and 11 with nonischemic heart disease; LV ejection fraction <40%) were randomized to receive metoprolol or placebo in a treatment protocol of titration plus 3 months of stable therapy. Seven patients were not included in analysis because of withdrawal from the study, incomplete follow-up, or nonanalyzable PET data. The rate of oxidative metabolism (k) was measured using C-11-acetate PET, and stoke volume index (SVI) was measured using echocardiography. The work-metabolic index was calculated as follows: (systolic blood pressure x SVI x heart rate)/k. No significant change in oxidative metabolism occurred with placebo (k=0.061+/-0.022 to 0.054+/-0.012 per minute). Metoprolol reduced oxidative metabolism (k=0.062+/-0. 024 to 0.045+/-0.015 per minute; P:=0.002). The work-metabolic index did not change with placebo (from 5.29+/-2.46 x 10(6) to 5.14+/-2. 06 x 10(6) mm Hg. mL/m(2)), but it increased with metoprolol (from 5. 31+/-2.15 x 10(6) to 7.08+/-2.36 x 10(6) mm Hg. mL/m(2); P:<0.001).

CONCLUSIONS

Selective beta-blocker therapy with metoprolol leads to a reduction in oxidative metabolism and an improvement in cardiac efficiency in patients with LV dysfunction. It is likely that this energy-sparing effect contributes to the clinical benefits observed with beta-blocker therapy in this patient population.