Left ventricular inotropic reserve and right ventricular function predict increase of left ventricular ejection fraction after beta-blocker therapy in nonischemic cardiomyopathy

Improved Right Ventricular Systolic Function After Cardiac Resynchronization Therapy in Patients With Heart Failure

BACKGROUND

Since the introduction of cardiac resynchronization therapy (CRT) to improve left ventricular function, the effect of CRT on the right ventricle in patients with heart failure has not been well described.

METHODS

We evaluated the effect of CRT on right ventricular systolic function in 20 patients (80% men; mean [SD] age, 58.5 [9.8] y) with cardiomyopathy and right ventricular systolic dysfunction (New York Heart Association class III or IV, left ventricular ejection fraction ≤35%, and QRS interval ≥120 ms). The median follow-up time was 15 months. Right ventricular systolic function, defined as a tricuspid annular plane systolic excursion (TAPSE) index of 16 mm or less, was evaluated in patients before and after CRT.

RESULTS

Twelve (60%) patients had ischemic cardiomyopathy, and 12 (60%) patients had left bundle branch block detected using surface electrocardiogram. The mean (SD) QRS duration was 160.5 (24.4) ms. From before CRT to the time of follow-up after CRT, the mean (SD) ejection fraction increased significantly from 22.5% (5.6%) to 29.4% (7.4%) (P < .001). The mean (SD) TAPSE index also increased significantly from 13.70 (1.78) mm to 16.50 (4.77) mm (P = .018). Eleven (55%) patients showed improved right ventricular systolic function (TAPSE ≥16 mm) after CRT. Patients with a favorable right ventricular response to CRT were significantly older (64.6 [8.2] y vs 53.6 [8.4] y, respectively) and more likely to have nonischemic origin of cardiomyopathy than were patients with unimproved right ventricular function (66.7% vs 18.2%, respectively).

CONCLUSION

Our findings indicate that CRT is associated with improved right ventricular systolic function in patients with heart failure and right ventricular systolic dysfunction. Patients with nonischemic heart disease more often show improved right ventricular function after CRT.

Impact of β-blocker therapy on right ventricular function in heart failure patients with reduced ejection fraction. A prospective evaluation

BACKGROUND

Beta-blocker (β-blocker) therapy has been shown to improve mortality and reduce hospitalizations in patients with heart failure (HF) with reduced ejection fraction (HFrEF). Although the physiological action mechanisms of β-blockers are well described, their effects on right ventricular (RV) function have not been prospectively studied.

OBJECTIVE

This prospective study aimed to (a) evaluate whether β-blocker therapy impacts RV remodeling based on echo parameters and (b) determine the predictive echo factors of β-blocker therapy response.

METHODS

From September 2017 to September 2018, HF patients were prospectively enrolled using CIBIS criteria: Class II, III, or IV HF; left ventricular ejection fraction (LVEF) of ≤40%; hospitalized for HF within the previous 12 months. Echo evaluation was performed before initiating β-blocker therapy and 3 months after optimal dose adjustment. Based on previous studies, patients with (absolute) LVEF ≥ 5% improvement were considered significant β-blocker therapy responders.

RESULTS

Overall, 40 patients (pts) completed the study, characterized as follows by age: 70 ± 10 years; gender: 10 women; cardiomyopathy etiology: idiopathic in 24 and ischemic in 16; NYHA Class: II in 22 and III in 10; LVEF: 32 ± 5%; and NTProBNP: 2665 ± 2400 pg/mL. The final population comprised 32 pts (79%), with eight (21%) excluded: two because of β-blocker therapy intolerance, one lost to follow-up, and five withdrew from the study. Under β-blocker therapy, several echo parameters significantly improved: LVEF from 31.7 ± 9 to 40.5 ± 9 (P < .0001); LV end-diastolic volume (EDV) from 154 ± 54 to 143 ± 45 mL (P = .06); LV end-systolic volume (ESV) from 107 ± 49 to 88 ± 37 mL (P = .0006); LV ES from 46 ± 11 to 64 ± 13 mL (P = .008); LV end-diastolic diameter (EDD) from 57 ± 9 to 54 ± 6 mm (P = .04); LV end-systolic diameter (ESD) from 48 ± 10 to 44 ± 7 mm (P = .007); and right ventricular systolic pressure (RV SP) from 39 ± 10 to 32 ± 8 mm Hg (P = .0001). Significant modifications were observed in terms of RV echo parameters: right ventricular (RV) size decreased from 30 ± 4 to 27 ± 5 mm (P = .03), while RV systolic function significantly improved based on tricuspid annular plane systolic excursion (TAPSE) (16.5 ± 4 vs. 19 ± 4 mm; 0.0006); DTI-derived tricuspid lateral annular systolic velocity wave (S') (10 ± 2 vs. 11.3 ± 3 cm/s; P = .03); and RIMP (Tei index) (0.5 ± 0.1 vs 0.46 ± 0.1; P = .04). RV 2D fractional area change (%) did not significantly differ despite a clear improvement tendency (35 ± 6 vs. 37 ± 4%; P = .1). No significant modifications were observed concerning LV diastolic parameters. Overall, β-blocker echo responders (n = 23/32; 72%) exhibited the same left and right echo parameters. No echo variables predicted the β-blocker response.

CONCLUSIONS

In HFrEF pts, β-blocker therapy significantly improves LV and RV systolic remodeling. Accordingly, β-blocker therapy could be applied as soon as possible in HFrEF patients with right ventricular dysfunction so as to limit RV remodeling.

Left ventricular ejection fraction as therapeutic target: is it the ideal marker?

Heart failure (HF) consists the fastest growing clinical cardiac disease. HF patients are categorized on the basis of underlying left ventricular ejection fraction (LVEF) into HF with preserved EF (HFpEF), reduced LVEF (HFrEF), and mid-range LVEF (HFmrEF). While LVEF is the most commonly used surrogate marker of left ventricular (LV) systolic function, the implementation of two-dimensional echocardiography in estimating this parameter imposes certain caveats on current HF classification. Most importantly, LVEF could fluctuate in repeated measurements or even recover after treatment, thus blunting the borders between proposed categories of HF and enabling upward classification of patients. Under this prism, we sought to summarize possible procedures to improve systolic function in patients with HFrEF either naturally or by the means of pharmacologic and non-pharmacologic treatment and devices. Therefore, we reviewed established pharmacotherapy, including beta-blockers, inhibitors of renin-angiotensin-aldosterone axis, statins, and digoxin as well as novel treatments like sacubitril-valsartan, ranolazine, and ivabradine. In addition, we assessed evidence in favor of cardiac resynchronization therapy and exercise training programs. Finally, innovative therapeutic strategies, including stem cells, xanthine oxidase inhibitors, antibiotic regimens, and omega-3 polyunsaturated fatty acids, were also taken into consideration. We concluded that LVEF is subject to changes in HF after intervention and besides the aforementioned HFrEF, HFpEF, and HFmrEF categories, a new entity of HF patients with recovered LVEF should be acknowledged. An improved global and refined LV function assessment by sophisticated imaging modalities and circulating biomarkers is expected to render HF classification more accurate and indicate patients with viable-yet dysfunctional-myocardium and favorable characteristics as the ideal candidates for LVEF recovery by individualized HF therapy.

Inotropic Effects of Prostacyclins on the Right Ventricle Are Abolished in Isolated Rat Hearts With Right-Ventricular Hypertrophy and Failure

BACKGROUND

Prostacyclin mimetics are vasodilatory agents used in the treatment of pulmonary arterial hypertension. The direct effects of prostanoids on right-ventricular (RV) function are unknown. We aimed to investigate the direct effects of prostacyclin mimetics on RV function in hearts with and without RV hypertrophy and failure.

METHODS

Wistar rats were subjected to pulmonary trunk banding to induce compensated RV hypertrophy (n = 32) or manifest RV failure (n = 32). Rats without banding served as healthy controls (n = 30). The hearts were excised and perfused in a Langendorff system and subjected to iloprost, treprostinil, epoprostenol, or MRE-269 in increasing concentrations. The effect on RV function was evaluated using a balloon-tipped catheter inserted into the right ventricle.

RESULTS

In control hearts, iloprost, treprostinil, and MRE-269 improved RV function. The effect was, however, absent in hearts with RV hypertrophy and failure. Treprostinil and MRE-269 even impaired RV function in hearts with manifest RV failure.

CONCLUSIONS

Iloprost, treprostinil, and MRE-269 improved RV function in the healthy rat heart. RV hypertrophy abolished the positive inotropic effect, and in the failing right ventricle, MRE-269 and treprostinil impaired RV function. This may be related to changes in prostanoid receptor expression and reduced coronary flow reserve in the hypertrophic and failing right ventricle.

Contractile reserve and cardiopulmonary exercise parameters in patients with dilated cardiomyopathy, the two dimensions of exercise testing

BACKGROUND

Left ventricular (LV) contractile reserve assessed using imaging and cardiopulmonary exercise testing (CPX) has been shown to predict outcome in patients with dilated cardiomyopathy (DCM). Few clinical studies have, however, analyzed the relationship between them.

METHODS

A cohort of 75 ambulatory patients with DCM underwent stress treadmill echocardiography with CPX. LV contractile reserve was calculated as absolute change (ΔLVEF=LVEF_peak -LVEF_rest ) and percent change (%LVEF=[(LVEF_peak -LVEF_rest )/LVEF_peak) ]×100) in LVEF, circumferential and longitudinal strain (LS). Exercise capacity was measured as peak oxygen uptake (peak VO₂ ) and ventilatory efficiency as the slope of minute ventilation to CO₂ production (VE/VCO₂ slope). Values of contractile reserve were compared to matched controls. We also explored which metric of ventricular response (absolute or percent change) was less dependent on baseline LV function.

RESULTS

Patients with DCM had a mean age, rest and peak LVEF of 44±10 years, 42±10% and 50±12%, respectively. Among parameters of contractile reserve, peak cardiac output was the strongest parameter associated with peak VO₂ (r=.63, P<.001). Along with age, sex, and BMI, it explained more than 70% of the variance in peak VO₂ . In contrast, LVEF and LS were only weakly related to peak VO₂ . With regard to ventilatory efficiency, the strongest parameter that emerged was right atrial volume index (r=.36, P<.001). Percent change in LVEF was more independent of baseline function than absolute change.

CONCLUSION

Echocardiographic contractile reserve and CPX provide complementary information. Percent change in contractile reserve was most independent of baseline function, therefore may be preferred when analyzing the ventricular response to exercise.

Cardio-Pulmonary-Renal Interactions: A Multidisciplinary Approach

Over the past decade, science has greatly advanced our understanding of interdependent feedback mechanisms involving the heart, lung, and kidney. Organ injury is the consequence of maladaptive neurohormonal activation, oxidative stress, abnormal immune cell signaling, and a host of other mechanisms that precipitate adverse functional and structural changes. The presentation of interorgan crosstalk may include an acute, chronic, or acute on chronic timeframe. We review the current, state-of-the-art understanding of cardio-pulmonary-renal interactions and their related pathophysiology, perpetuating nature, and cycles of increased susceptibility and reciprocal progression. To this end, we present a multidisciplinary approach to frame the diverse spectrum of published observations on the topic. Assessment of organ functional reserve and use of biomarkers are valuable clinical strategies to screen and detect disease, assist in diagnosis, assess prognosis, and predict recovery or progression to chronic disease.

Adaptive capacity of the right ventricle: why does it fail?

Only in recent years has the right ventricle (RV) function become appreciated to be equally important to the left ventricle (LV) function to maintain cardiac output. Right ventricular failure is, irrespectively of the etiology, associated with impaired exercise tolerance and poor survival. Since the anatomy and physiology of the RV is distinctly different than that of the LV, its adaptive mechanisms and the pathways involved are different as well. RV hypertrophy is an important mechanism of the RV to preserve cardiac output. This review summarizes the current knowledge on the right ventricle and its response to pathologic situations. We will focus on the adaptive capacity of the right ventricle and the molecular pathways involved, and we will discuss potential therapeutic interventions.

Analysis of cardiac exams: electrocardiogram and echocardiogram use In Duchenne muscular dystrophies

Introduction Duchenne Muscular Dystrophies (DMD) is a genetic muscle disorder that causes degeneration and atrophy of skeletal muscle and heart. Objective The aim of this survey is accomplish an evaluation electrocardiographic and echocardiography in the patients bearers of Duchene Muscular Dystrophies (DMD), to observe which alterations, which the degree of cardiac compromising these patient present and the effectiveness of these exams in the evaluation cardiologic. Methods Nine patients of the sex male bearers of DMD, with medium age of 14.12 ± 4.19 years, varying of 7 to 23 years were appraised. All were submitted to the evaluation physiotherapy and the cardiologic: electrocardiogram and echocardiogram. Results The experimental conditions of the present survey we propitiate the observation of the alterations echocardiography, as well as: significant increase in the diastolic diameter of the left ventricular (LV), increase in the systolic diameter of the left atrium (LA), and significant decrease of the ejection fraction of the LV, characterizing global systolic function reduced, and of the alterations electrocardiographic suggested possible overload of RV, septum hypertrophy, blockade of left previous fascicle and overload of atrium left. Compatible alterations of hypertrophy left ventricular were not observed. Conclusion The evidences corroborate with the data described in the literature in the characterization of an important heart compromising that these patient present, like this the evaluation cardiologic, through the complemented exams of the echocardiography and electrocardiography provide important information for the prognostic, the accompaniment, and the treatment of patient bearers of DMD.

Global myocardial contractile reserve assessed by high-dose dobutamine stress echocardiography predicts response to the cardiac resynchronization therapy

BACKGROUND

Myocardial contractile reserve (CR) is a strong prognostic factor in patients with heart failure. The presence of significant myocardial fibrosis can lead to a reduced response to cardiac resynchronization therapy (CRT). We assumed that myocardial CR assessed by high-dose dobutamine stress echocardiography (DSE) would predict response to CRT.

METHODS

Fifty-two consecutive symptomatic patients with heart failure (New York Heart Association [NYHA] class III), with depressed ejection fraction (EF) of the left ventricle (26.3 ± 6.9%) and dyssynchronous contractions (QRS duration 149.8 ± 23.8 msec) underwent DSE before CRT implantation. The difference in EF at rest and at peak (40 μg/kg per minute) DSE indicated global CR. Responders to CRT were defined by a decrease in left ventricular end-systolic volume of ≥15% and/or an increase in EF of ≥5% after 6 months of CRT.

RESULTS

During high-dose dobutamine infusion, responders (28 patients, 54%) showed a greater increase in EF compared with nonresponders (Δ 11 ± 7% vs. Δ 2 ± 9%, P = 0.007). CR correlated moderately with an improvement in EF after 6 months of CRT (r = 0.50, P = 0.0009). Furthermore, responders showed significant improvement in clinical status, evaluated by a reduction in NYHA functional class (-0.8 ± 0.6 vs. 0.1 ± 0.4, P = 0.02), compared with nonresponders. A 7% exercise-induced increase in EF yielded sensitivity of 79% and specificity of 87% in predicting the response to CRT after 6 months.

CONCLUSIONS

Myocardial CR assessed by high-dose DSE can play a potentially important role in identifying responders to CRT.

Isovolumic contraction acceleration before and after percutaneous closure of atrial septal defects

Aim

To compare systemic right ventricular function by isovolumic myocardial acceleration before and 6 months after the percutaneous closure of atrial septal defects (ASD).

Material and methods

Patients admitted to our tertiary center for the percutaneous closure of atrial septal defects between January 2010 and August 2012 constituted the study group. Right ventricular function of patients was assessed by tissue Doppler echocardiography before and after surgery. Echocardiographic data in patients were compared to age-matched controls without any cardiac pathology and studied in identical fashion mentioned below.

Results

A total of 44 patients (24 males, 20 females) and 44 age-matched controls (25 males, 19 females) met the eligibility criteria for the study. Right ventricular end-diastolic and end-systolic volume, right ventricular end-diastolic diameter measurements on echocardiogram, and pulmonary artery pressures in both pre- and post-ASD groups were significantly higher than in controls. Tricuspid annular plane systolic excursion and isovolumic myocardial acceleration measurements significantly increased after the percutaneous closure of the defect; however, post-ASD measurements were still significantly lower than the controls.

Conclusions

Atrial septal defect device closure resulted in a significant increase of isovolumic myocardial acceleration measurements. Tissue Doppler analysis of regional myocardial function offers new insight into myocardial compensatory mechanisms for acute and chronic volume overload of both ventricles.

Inotropic contractile reserve can risk-stratify patients with HIV cardiomyopathy: a dobutamine stress echocardiography study

OBJECTIVES

The purpose of this study was to assess whether inotropic contractile reserve (ICR) during dobutamine stress echocardiography (DSE) could risk-stratify patients with human immunodeficiency virus (HIV) cardiomyopathy and predict improvement of left ventricular ejection fraction (LVEF).

BACKGROUND

HIV cardiomyopathy is an important cause of heart failure and death. ICR is associated with better survival and improvement of LVEF in patients with ischemic and nonischemic cardiomyopathies. However, the prognostic value of ICR in patients with HIV cardiomyopathy is unknown.

METHODS

Patients with HIV cardiomyopathy and a LVEF <45% who were referred for DSE were enrolled. ICR was evaluated by the delta wall motion score index (ΔWMSI), calculated as the difference between rest and peak WMSI. Patients were followed for cardiac death and change in LVEF on follow-up.

RESULTS

Sixty patients (75% men; age, 54 ± 9 years) with HIV cardiomyopathy (mean LVEF, 28 ± 11%) formed the study group. After 2.4 ± 2.1 years, 11 cardiac deaths occurred (event rate of 7.6%/year). A receiver-operating characteristic curve identified a ΔWMSI of 0.38 as an optimal cut point for the presence of ICR, with a specificity of 88% and a sensitivity of 73% for the prediction of cardiac death. On univariable analysis, the absence of ICR (hazard ratio: 6.6; 95% confidence interval: 1.93 to 22.62; p = 0.003) and New York Heart Association functional class IV (hazard ratio: 7.2; 95% confidence interval: 2.20 to 23.65; p = 0.001) were the only predictors of cardiac death. After 2.1 ± 1.8 years, 41 patients had a follow-up echocardiogram. LVEF improvement from baseline occurred in 23 patients (56%), more so in patients with ICR than without ICR. A ΔWMSI of 0.59 predicted improvement in the LVEF with a specificity of 78% and a sensitivity of 74%.

CONCLUSIONS

The presence of ICR during DSE can risk-stratify and predict subsequent improvement in LVEF in patients with HIV cardiomyopathy.

Reduced right ventricular ejection fraction and increased mortality in chronic systolic heart failure patients receiving β-blockers: insights from the BEST trial

BACKGROUND

Right ventricular ejection fraction (RVEF) < 20% is an independent predictor of poor outcomes in patients with advanced chronic systolic heart failure (HF). The aim of this study was to examine if the adverse effect of abnormally reduced RVEF varies by the receipt of beta-blockers.

METHODS

In the Beta-Blocker Evaluation of Survival Trial (BEST), 2708 patients with chronic advanced HF and left ventricular ejection fraction < 35%, receiving standard background therapy with renin-angiotensin inhibition, digoxin, and diuretics, were randomized to receive bucindolol or placebo. Of these 2008 had data on baseline RVEF, and 14% (146/1017) and 13% (125/991) of the patients receiving bucindolol and placebo respectively had RVEF < 20%.

RESULTS

Among patients in the placebo group, all-cause mortality occurred in 33% and 43% of patients with RVEF ≥ 20% and < 20% respectively (unadjusted hazard ratios {HR}, 1.33; 95% confidence intervals {CI}, 0.99-1.78; p = 0.055 and adjusted HR, 0.99; 95% CI, 0.71-1.37; p = 0.934). Among those receiving bucindolol, all-cause mortality occurred in 28% and 49% of patients with RVEF ≥ 20% and < 20% respectively (unadjusted HR, 2.15; 95% CI, 1.65-2.80; p < 0.001 and adjusted HR, 1.50; 95% CI, 1.08-2.07; p = 0.016). These differences were statistically significant (unadjusted and adjusted p for interaction, 0.016 and 0.053 respectively).

CONCLUSIONS

In ambulatory patients with chronic advanced systolic HF receiving renin-angiotensin inhibition, digoxin, and diuretics, RVEF < 20% had no intrinsic association with mortality. However, in those receiving additional therapy with bucindolol, RVEF < 20% had a significant independent association with increased risk of mortality.

Right ventricular ejection fraction <20% is an independent predictor of mortality but not of hospitalization in older systolic heart failure patients

BACKGROUND

Reduced right ventricular ejection fraction (RVEF) is associated with poor outcomes in patients with chronic systolic heart failure (HF). Although most HF patients are older adults, little is known about the relationship between low RVEF and outcomes in older adults with systolic HF.

METHODS

Of the 2008 Beta-Blocker Evaluation of Survival Trial (BEST) participants with systolic HF (left ventricular ejection fraction ≤ 35%) 822 were ≥ 65 years and had data on baseline RVEF estimated by gated-equilibrium radionuclide ventriculography. Using RVEF ≥ 40% (n = 308) as reference, we examined association of RVEF 30-39% (n = 214), 20-29% (n = 206) and <20% (n = 94) with outcomes using Cox regression models.

RESULTS

All-cause mortality occurred in 36%, 40%, 39% and 56% of patients with RVEF ≥ 40%, 30-39%, 20-29% and <20% respectively. Compared with RVEF ≥ 40%, unadjusted hazard ratios (HR) and 95% confidence intervals (CI) for all-cause mortality associated with RVEF 30-39%, 20-29% and <20% were 1.19 (0.90-1.57; P = 0.220), 1.13 (0.84-1.51; P = 0.423) and 1.97 (1.43-2.73; P<0.001) respectively. Respective multivariable-adjusted HR's (95% CI's) for all-cause mortality were 1.19 (0.88-1.60; P = 0.261), 1.00 (0.73-1.39; P = 0.982) and 1.70 (1.14-2.53; P = 0.009). Adjusted HR's (95% CI's) associated with RVEF <20% (versus ≥ 40%) for cardiovascular mortality and HF mortality were 1.79 (1.17-2.76; P = 0.008) and 1.97 (1.02-3.83; P = 0.045) respectively. RVEF had no independent association with sudden cardiac death, all-cause or HF hospitalization.

CONCLUSIONS

Abnormally low RVEF is a significant independent predictor of mortality, but not of HF hospitalization, in older adults with systolic HF.

The concept of ventricular reserve in heart failure and pulmonary hypertension: an old metric that brings us one step closer in our quest for prediction

PURPOSE OF REVIEW

Ventricular reserve is emerging a strong predictor of outcome in heart failure and cardiovascular disease. Ventricular reserve is the term used to describe the extent of increase or change in ventricular function that occurs during exercise or pharmacological stress (typically with dobutamine).

RECENT FINDINGS

The interest in ventricular reserve lies in its ability to assess viability in coronary artery disease, to predict clinical outcome and response to therapy in patients with heart failure and to screen patients for early cardiovascular disease.

SUMMARY

In this paper, we will review the emerging role of ventricular reserve in heart failure and pulmonary hypertension. We will also explore the mechanisms involved in the pathophysiology of impaired ventricular reserve and discuss future directions of research in the field.

β-blockers and their mortality benefits: underprescribed in heart failure and chronic obstructive pulmonary disease

This article discusses the most recent insights into the actions of β-blockers on the heart and lungs, highlighting that β-blockers should have a place in the treatment of patients with chronic obstructive pulmonary disease (COPD), especially in those with coexisting cardiovascular disease or arterial hypertension. Practical studies clearly show underutilization of β-blockers in patients with heart failure and COPD, which seems to be caused by an unnecessary fear for adverse effects on the lungs, and the ‘outdated’ adverse effects mentioned on instruction leaflets.

Interest of β-blockers in patients with right ventricular systemic dysfunction

BACKGROUND

β-blockers improve the prognosis of patients with cardiac failure due to left ventricular systolic dysfunction. The aim of this study was to assess the efficacy of β-blockers in patients with dysfunctional systemic right ventricle.

METHODS

Fourteen patients with systemic right ventricle following a Mustard or a Senning operation for the transposition of the great arteries, or congenitally corrected transposition were included in the study. All had a decreased systemic right ventricular ejection fraction despite having standard cardiac failure therapy. Quality of life, New York Heart Association class, aerobic capacity, and systemic right ventricular function were assessed before treatment with β-blockers and at the end of the follow-up period, mean of 12.8 months with a range from 3 to 36 months.

RESULTS

Change in New York Heart Association class was significant (p = 0.016). Quality of life improved significantly throughout the study from a median grade 2 with a range from 1 to 3 to a median grade 1 with a range from 1 to 2 (p = 0.008). Systemic right ventricular ejection fraction assessed by radionuclide ventriculography improved significantly from a median of 41% (range: 29-53%) to 49% (range: 29-62%; p = 0.031). However, the change in thee ejection fraction assessed by magnetic resonance imaging was not significant from a median of 29% (range: 12-47%) to 32% (range: 22-63%; p = 0.063).

CONCLUSION

In patients with cardiac failure due to systemic right ventricular dysfunction, β-blockers improve New York Heart Association class, quality of life, and systemic right ventricular ejection fraction assessed by radionuclide ventriculography.

Mechanisms Underlying Improvements in Ejection Fraction With Carvedilol in Heart Failure

Background— Reductions in heart rate (HR) with β-blocker therapy have been associated with improvements in ejection fraction (EF). However, the relative contributions of HR reduction, positive inotropism, afterload reduction, and reverse remodeling to improvements in EF are unknown.

Methods and Results— Twenty-nine patients (63�12 years old) with New York Heart Association class II-III heart failure underwent serial measurements of left ventricular volumes using 3-dimensional echocardiography and blood pressures by sphygmomanometry at baseline, 2 weeks, 2, 6, and 12 months after initiation of carvedilol. From these parameters, left ventricular contractility (indexed by the end-systolic pressure-volume ratio), total peripheral resistance, and effective arterial elastance (E a ) were derived. Overall, EF increased by 7-percentage points after 6 months of therapy (from 25�9 to 32�9, P <0.0001). This change was due to an increase in stroke volume ( P <0.001) with no significant change in end-diastolic volume ( P =0.15). The EF change correlated with increased contractility, decreased HR and decreased total peripheral resistance ( P <0.003 in each case). In those patients whose EF increased at least 5 points, ≈60% of the increase was due to HR reduction, ≈30% was due to increased contractility, and <20% was due to the decrease in total peripheral resistance.

Conclusions— Decreased HR, improved chamber contractility and afterload reduction each contributed significantly to improved EF with carvedilol.

Myocardial beta-adrenergic receptor density assessed by 11C-CGP12177 PET predicts improvement of cardiac function after carvedilol treatment in patients with idiopathic dilated cardiomyopathy

We evaluated whether myocardial beta-adrenergic receptor (beta-AR) density, as determined by 11C-CGP12177 PET, could predict improvement of cardiac function by beta-blocker carvedilol treatment in patients with idiopathic dilated cardiomyopathy (IDC).

METHODS

Ten patients with IDC (left ventricular ejection fraction [LVEF]<45%) were studied. Myocardial beta-AR density was estimated using 11C-CGP12177 PET before treatment with carvedilol. Changes of LVEF in response to dobutamine infusion (DeltaLVEF-dobutamine) were also measured by echocardiography. Changes of LVEF (DeltaLVEF-carvedilol) were evaluated after 20 mo of carvedilol treatment.

RESULTS

Baseline myocardial beta-AR density significantly correlated with DeltaLVEF-carvedilol (r=-0.88, P<0.001). In contrast, DeltaLVEF-dobutamine did not correlate with DeltaLVEF-carvedilol (P=0.65). Myocardial beta-AR density was the significant multivariate independent predictor of DeltaLVEF-carvedilol (beta=-0.88, P<0.001) among univariate predictors, including functional class (r=0.76, P<0.05), plasma norepinephrine (r=0.85, P<0.01), LVEF (r=-0.64, P<0.05), and age as confounding factors. Furthermore, myocardial beta-AR density was significantly correlated with plasma norepinephrine (r=-0.79, P<0.01) and LVEF (r=0.70, P<0.05).

CONCLUSION

Myocardial beta-AR density is more tightly related to improvement of LVEF-carvedilol than is cardiac contractile reserve in patients with IDC. Patients with decreased myocardial beta-AR have higher resting adrenergic drive, as reflected by plasma norepinephrine, and may receive greater benefit from being treated by antiadrenergic drugs.

Myocardial contractile reserve predicts improvement in left ventricular function after cardiac resynchronization therapy

BACKGROUND

Myocardial contractile reserve has been shown to provide important prognostic information in patients with heart failure. We hypothesized that myocardial contractile reserve would predict left ventricular (LV) reverse remodeling after cardiac resynchronization therapy (CRT).

METHODS

Thirty-one consecutive patients with heart failure (LV ejection fraction [LVEF] 26% +/- 7%, 35% nonischemic cardiomyopathy) underwent echocardiography during low-dose dobutamine infusion before CRT implantation to assess global contractile reserve (improvement in LVEF) and local contractile reserve in the region of the LV pacing lead (assessed by radial strain using speckle tracking analysis). Responders were defined by a decrease in LV end-systolic volume > or = 15% after 6 months of CRT.

RESULTS

During low-dose dobutamine infusion, responders showed a greater increase in LVEF compared with nonresponders (delta 13% +/- 8% vs 3% +/- 4%, P < .001). Furthermore, contractile reserve was directly related to improvement in LVEF after 6 months of CRT (r = 0.80, P < .001). Moreover, a cutoff value of > 7.5% increase in dobutamine-induced LVEF exhibited a sensitivity of 76% and a specificity of 86% to predict response after 6 months of CRT (area under the curve 0.87). Lastly, contractile reserve in the region in the LV pacing lead was present only in responders (delta strain during low-dose dobutamine 6% +/- 5% in responders vs -1% +/- 4% in nonresponders, P = .002).

CONCLUSIONS

The current study demonstrates that myocardial contractile reserve (> 7.5% increase in LVEF during low-dose dobutamine infusion) predicts LV reverse remodeling after CRT.

The function of left ventricular basal segments is most important for long-term recovery

Adrenergic beta-blockade is the most potent pharmacological therapy for the improvement of global left ventricular (LV) function in heart failure. A substantial portion of patients responds poorly to beta-blockers, but there is scarce information about LV regional function and recovery. We intended to evaluate the effects of beta-blockade on LV regional function and recovery, contractile reserve (CR) and response to long-term treatment.

METHODS

Twenty-two patients with heart failure were investigated at rest and during dobutamine stress echocardiography (DSE), before and after 6 months of metoprolol treatment. LV function was evaluated by global ejection fraction (EF), and by regional function in basal, mid and apical segments.

RESULTS

Recovery of LV global function (increase in EF >5%) after metoprolol treatment was significantly and best correlated to CR in basal segments of the ventricle (r=0.79, p<0.001), in comparison with function of mid and apical segments. The correlation between global recovery and global CR was r=0.55, p=0.007. In a multivariate logistic regression, including global and regional CR, age, gender, etiology of heart failure, ACE-inhibitor treatment, heart rate, and baseline EF, only basal CR was independently associated with recovery, OR 1.07 [95% CI, 1.01-1.21], p=0.019.

CONCLUSION

The strongest association for prediction of LV recovery after metoprolol treatment was found regarding function of basal segments of the ventricle. Patients that responded favourably to beta-blockade had a significantly better CR, and treatment effect, in these segments. This gives further evidence for the importance of myocardial function in basal segments to the contribution of recovery and LV global function.

Intra-observer and interobserver reproducibility of right ventricle volumes, function and mass by cardiac magnetic resonance

OBJECTIVES

Cardiac magnetic resonance (CMR) allows quick and non-invasive evaluation both of right ventricle (RV) volume and function, which are important in many heart diseases. We have evaluated CMR intra- and interobserver reproducibility in different conditions of RV dimension and function.

METHODS

We have analysed CMR exams of 45 subjects, randomly selected from our database according to RV end-diastolic volume (EDV; 15-subject groups with EDV < 25th, 25-75th and > 75th percentiles of a normal control population). Selected subjects were of both sexes (male/female 33/12) and of variable age (8-83 years) and body surface (0.9-2.3 m). RV end-diastolic and end-systolic volumes (ESV), ejection fraction (EF) and mass were blindly evaluated by two operators. Bland-Altman bias and coefficient of variability (CoV) were used to assess intra- and interobserver reproducibility.

RESULTS

A wide range of EDV (range = 46-239 ml), ESV (20-129 ml) and EF (6-64%) was observed. The intra-observer bias was -5 ml for EDV, -2 ml for ESV, -1% for EF and 5 g for mass, with a CoV of 7-12%. The interobserver bias was 5 ml for EDV, 2 ml for ESV, 2% for EF and 6 g for mass, with a CoV of 8-13%. Analysis by tertiles showed EF assessment variability to be higher in the lower tertiles at intra-observer (P < 0.036) and, above all, at interobserver (P < 0.000) analysis. Mass assessment variability was higher in the upper tertile (P < 0.004) at intra-observer analysis.

CONCLUSIONS

Intra- and interobserver reproducibility of RV parameters assessed by CMR are adequate in a wide range of RV dimensions and function. However, caution is required with respect to the significance of small changes of EF and mass in the case of poor function and hypertrophy of the RV, respectively.

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.

Effect of bisoprolol on right ventricular function and brain natriuretic peptide in patients with heart failure

Beta-blocker use improves left ventricular ejection fraction (LVEF) in patients with heart failure. A similar effect of b blockers on right ventricular function has been proposed, although the effect of bisoprolol, a highly selective b-1 blocker, on right ventricular function has not been assessed. This study investigated the short-term effect of bisoprolol on right ventricular function in chronic heart failure patients. A cohort of 30 heart failure patients who were not taking b blockers at baseline was studied prospectively. Right ventricular ejection fraction (RVEF) and LVEF were measured at both baseline and 4 months by radionuclide angiography. Bisoprolol was up-titrated during four monthly visits by a preestablished protocol to a target dose of 10 mg/d. The dose of vasodilators was not changed. Quality of life and brain natriuretic peptide level were assessed. Mean age was 62.7+/-14.3 years. Baseline RVEF was 30.7%+/-6.3% and baseline LVEF was 21.7%+/-9.4%. Mean bisoprolol dose reached was 5.3+/-3.9 mg daily. At 4 months, RVEF significantly increased by 7.1% (95% confidence interval, 3.9-10.2; p=0.0001) and LVEF also increased significantly by 7.9% (95% confidence interval, 4.0%-11.9%; p=0.0003). Quality-of-life score improved from 42.8 to 30.8 (p=0.047). No correlation was found between brain natriuretic peptide levels and RVEF. Bisoprolol treatment for 4 months resulted in a significant improvement of RVEF, which paralleled the improvement of LVEF.

Right ventricular volume measurement with single-plane Simpson's method based on a new half-circle model

BACKGROUND

The complexity of right ventricular (RV) shape makes it more difficult for measuring its volume. However, the short-axis view of the right ventricle usually is crescent and might be assumed as half of a circle. This hypothesis can be applied to calculate RV volume by using the single-plane Simpson's method, but the final RV volume should be about half of the original calculated value. The aim of this study was to test the accuracy of RV volume measurement based on this new assumption in human RV casts.

METHODS

Fifteen human RV casts were scanned with multislice helical CT and RV sagittal image that corresponds to right anterior oblique view were reconstructed. Single-plane Simpson's method was used to calculate RV volumes. The calculated RV volume was defined as the original calculated value divided by 2. The true RV cast volume was determined by water displacement.

RESULTS

The true RV volume was 64.23+/-24.51 ml; the calculated volume was 53.18+/-26.22 ml. The calculated RV correlated closely with true volume with a regression equation of RV actual volume=21.04 0.406 x RV calculated volume (r=0.869, P<0.001), but significantly underestimated the actual volume by 11.05+/-13.09 ml (P<0.006).

CONCLUSION

Right ventricular volume could be calculated with single-plane Simpson's method based on the new proposed half-circle model.

Relation between contractile reserve and improvement in left ventricular function with beta-blocker therapy in patients with heart failure secondary to ischemic or idiopathic dilated cardiomyopathy

Beta blockers improve left ventricular (LV) ejection fraction but patient responses are heterogenous. We investigated the role of contractile reserve (CR) in predicting beta-blocker response in ischemic and nonischemic cardiomyopathy. Resting and low-dose dobutamine echocardiograms were recorded in 32 patients with heart failure (LV ejection fraction <or=35%), 18 with ischemic cardiomyopathy (IC), and 14 with idiopathic dilated cardiomyopathy (IDC). A segment was defined as CR positive (CR+) or negative (CR-) based on response to dobutamine. Patients were then classified as CR+ or CR- based on number of improved segments (IC group) or ejection fraction improvement (IDC group) in response to dobutamine. During follow-up (2, 6, and 14 months after beta-blocker initiation), response was measured by the percent of segments showing improved contractility from baseline, ejection fraction, and wall motion score index. In the IC group, the percent of improved segments was greater at 2 and 6 months in CR+ versus CR- (70% vs 15% and 39% vs 17%, p <0.05), whereas it was greater at all periods in the patients with IDC (36% vs 9% at 2 months, 50% vs 19% at 6 months, and 63% vs 42% at 14 months, p <0.05). Findings for ejection fraction and wall motion score index were similar. Therefore, time course and magnitude of improvement in LV function in patients with heart failure receiving beta blockers are related to CR status. CR predicts a greater early response in IC, whereas it predicts a greater response at all time periods in IDC. However, even patients without CR showed improvement in LV function at 14 months.

Heart failure in diabetic patients: utility of beta-blockade

BACKGROUND

Congestive heart failure (CHF) occurs with increased frequency in patients with diabetes and carries a higher risk of morbidity and mortality compared with nondiabetic persons. Diabetic patients are more likely to suffer from CHF and its consequences because of hypertensive and ischemic heart disease and diabetic cardiomyopathy.

METHODS

Intensive combination therapy, directed at the different aspects of the pathophysiology of CHF in diabetes patients, results in improved outcomes. Improvement of glycemia, reduction of low-density lipoprotein cholesterol levels, tight control of blood pressure, and antiplatelet therapy have been all shown to decrease the morbidity and mortality associated with CHF in diabetic patients. beta-blockade added to angiotensin-converting enzyme (ACE) inhibition has become an increasingly integral component of CHF therapy.

RESULTS

Improved outcome with beta-blockade treatment is due to decreased incidence of both sudden death and pump failure and is of particular benefit to diabetic patients during and after myocardial infarctions complicated by systolic dysfunction.

CONCLUSIONS

Based on retrospective analysis, beta-blocking agents with vasodilating properties may provide additional benefits in diabetic patients because they may improve insulin sensitivity and vasorelaxation.

Evidence of early impairments in both right and left ventricular inotropic reserves in children with Duchenne's muscular dystrophy

In Duchenne's muscular dystrophy (DMD), cardiac function deteriorates with time and heart failure is one of the major causes of death. The aim of the study was to determine if a decrease in the ventricular inotropic reserves could be an early sign of cardiac dysfunction in these children. Nineteen children with DMD (aged 9 to 18 years, mean age 13.6 +/- 2.4) underwent equilibrium radionuclide angiography at rest and during an inotropic stimulation with low-dose dobutamine perfusion (7.5 to 15 microg. kg(-1). min(-1)). In all patients, this investigation was short (<30 minutes), successful, and uncomplicated. At rest, left ventricular (LV) ejection fraction (EF) was normal (>0.50) in 79% of patients, and right ventricular (RV) EF was normal (>0.45) in 95%. There was a trend toward a decrease with age for rest LVEF (p = 0.051) but not for rest RVEF (p = 0.8). By contrast, marked declines with age could be documented for the increases (Delta) in LVEF and RVEF during dobutamine perfusion (p = 0.002 for DeltaLVEF and p = 0.015 for DeltaRVEF). Thus, by multivariate analysis, the sole best indicator of decline in cardiac function with age was LVEF determined with dobutamine. In children with DMD, low-dose dobutamine radionuclide angiography gives evidence of an early decline with age of the inotropic reserves of both ventricles.

Enoximone echocardiography: a novel test to evaluate left ventricular contractile reserve in patients with heart failure on chronic beta-blocker therapy

BACKGROUND

It has been suggested that an extensive contractile reserve identified recognised by means of dobutamine stress echocardiography may predict a better prognosis in patients with severe left ventricular dysfunction at rest. However, the clinical use of dobutamine stress echocardiography may be limited in patients with chronic heart failure by the substantial proportion of such patients treated with beta-blockers, since the inotropic response to adrenergic stimulation is known to be attenuated in patients receiving beta-adrenoceptor blockers. Enoximone is a positive inotropic agent that inhibits cyclic adenosine monophosphate-specific phosphosdiesterase. We therefore tested the hypothesis that enoximone may be an alternative to dobutamine in evaluating left ventricular contractile reserve in patients with systolic dysfunction on chronic beta-blocker therapy.

METHODS

We studied 26 patients (21 males and five females) with a mean age of 58 PlusMinus; 10 years: 11 were not receiving beta-blockers (noBB group); 15 were receiving carvedilol at a mean dose of 34 mg/day (BB group). Dobutamine was infused at doses of 5 and 10 micrograms/kg/min, and enoximone at a dose of 1.5 mg/kg.

RESULTS

The ejection fraction in the noBB group increased by 9% with dobutamine and 8.73% with enoximone (p = 0.86); in the BB group, it increased by 6% with dobutamine and 8.94% with enoximone (p = 0.03). Regional peak systolic velocities were evaluated by means of tissue Doppler imaging in four basal and four medium level segments. In the noBB group, they increased more with dobutamine than with enoximone in three of the eight segments; no significant differences were found in the BB group. Dobutamine induced non-sustained ventricular tachycardia in three patients and supraventricular tachycardia in one, whereas enoximone did not induce any repetitive arrhythmias.

CONCLUSIONS

Enoximone might be preferable to low-dose dobutamine for evaluating left ventricular contractile reserve in chronically beta-blocked heart failure patients as it is slightly more potent and has a better safety profile.

Major increase in brain natriuretic peptide indicates right ventricular systolic dysfunction in patients with heart failure

This study sought to investigate whether the presence of right ventricular systolic dysfunction with pre-existing left ventricular systolic dysfunction is associated with higher plasma brain natriuretic peptide (BNP) levels, compared with patients with isolated left ventricular dysfunction. Eighty-five patients referred for evaluation of isotopic ventricular function were prospectively included in the study. Left (LVEF) and right (RVEF) ventricular ejection fractions were evaluated by gated blood pool scintigraphy and compared with plasma BNP levels. BNP correlated negatively with LVEF, except in patients with ischaemic heart disease (P=0.09) and in patients with LVEF<40% (P=0.11). In contrast, BNP levels correlated negatively with RVEF for all subgroups. Among patients with RVEF<40%, no significant BNP difference was found between patients with or without additional left ventricular systolic dysfunction (P=0.51). Among patients with LVEF<40%, plasma BNP levels were significantly higher in patients with RVEF<40% than in patients with RVEF>/=40% (P=0.004) whereas age, renal function, clinical findings, ventricular volumes, LVEF or medication were not significantly different. In conclusion, an important increase in BNP levels in patients with left ventricular systolic dysfunction should be considered by cardiologists as an indication of high risk of right ventricular dysfunction and should justify further investigation.

Marked improvement in left ventricular ejection fraction during long-term beta-blockade in patients with chronic heart failure: clinical correlates and prognostic significance

BACKGROUND

Some patients with heart failure (HF) may have a marked improvement in left ventricular ejection fraction (LVEF) after long-term beta-blockade. We compared the clinical characteristics and the prognosis of these patients with those of other patients.

METHODS

One hundred seventy-one patients with chronic HF were assessed before and after 9 to 12 months of maintenance therapy with metoprolol or carvedilol.

RESULTS

Thirty-eight patients (22%) showed an increase in their LVEF >or=15 units (from 20% +/- 8% to 43% +/- 10%). Compared with the other patients (LVEF change from 21% +/- 7% to 26% +/- 9%, P <.0001 for differences between groups), these patients also had a greater decline in the left ventricular end-diastolic volume (from 175 +/- 74 mL/m(2) to 113 +/- 36 mL/m(2)) and in the right atrial, mean pulmonary artery, and pulmonary wedge pressures, with a greater increase in the cardiac index, stroke volume index, stroke work index, and maximal functional capacity. Their long-term prognosis was excellent, with a 2-year cumulative survival rate of 95%, versus 81% for the other patients, and a hospitalization-free survival rate of 73%, versus 50% for the other patients (all P <.05). By means of multivariate analysis, only the nonischemic cause of HF and the mean arterial pressure at baseline were independently associated with an increase of >or=0.15 in LVEF.

CONCLUSIONS

Patients who show a marked improvement in their LVEF after long-term beta-blockade have an excellent prognosis and have a high prevalence of nonischemic HF and a higher blood pressure at baseline.

Validation of myocardial acceleration during isovolumic contraction as a novel noninvasive index of right ventricular contractility: comparison with ventricular pressure-volume relations in an animal model

BACKGROUND

We have demonstrated that myocardial acceleration during isovolumic contraction (IVA) is a sensitive index of left ventricular contractile function. In this study, we assessed the utility of IVA to measure right ventricular (RV) contractile function.

METHODS AND RESULTS

We examined 8 pigs by using tissue Doppler imaging of the RV free wall and simultaneous measurements of intraventricular pressure, volume, maximal elastance (e(max)), preload recruitable stroke work, and dP/dt(max) by conductance catheterization. Animals were paced in the right atrium at a rate of 130 beats per minute (bpm). IVA was compared with elastance during contractility modulation by esmolol and dobutamine and during preload reduction and afterload increase by transient balloon occlusion of the inferior vena cava and pulmonary artery, respectively. Data were also obtained during incremental atrial pacing from 110 to 210 bpm. Esmolol led to a decrease in IVA and dP/dt(max). During dobutamine infusion, IVA, dP/dt(max), preload recruitable stroke work, and e(max) all increased significantly. During preload reduction and afterload increase, IVA remained constant up to a reduction of RV volume by 54% and an RV systolic pressure increase of 58%. Pacing up to a rate of 190 bpm led to a stepwise increase in IVA and dP/dt(max), with a subsequent fall at a pacing rate of 210 bpm.

CONCLUSIONS

IVA is a measurement of RV contractile function that is unaffected by preload and afterload changes in a physiological range and is able to measure the force-frequency relation. This novel index may be ideally suited to the assessment of acute changes of RV function in clinical studies.