Effect of spironolactone on ventricular arrhythmias in congestive heart failure secondary to idiopathic dilated or to ischemic cardiomyopathy

A review of the conservative versus invasive management of ischemic heart failure with reduced ejection fraction

Heart failure is increasing in terms of prevalence, morbidity, and mortality rates. Clinical trials and studies are focusing on heart failure as it is the destiny end-stage for several cardiovascular disorders. Recently, medical therapy has dramatically progressed with novel classes of medicines providing better quality of life and survival outcomes. However, heart failure remains a heavy impactful factor on societies and populations. Current guidelines from the American and European cardiac societies are not uniform with respect to the class and level of treatment recommendations for coronary artery disease patients with heart failure and reduced ejection fraction. The discrepancy among international recommendations, stemming from the lack of evidence from adequately powered randomized trials, challenges physicians in choosing the optimal strategy. Hybrid therapy including optimal medical therapy with revascularization strategies are commonly used for the management of ischemic heart failure. Coronary artery bypass graft (CABG) has proved its efficacy on improving long term outcome and prognosis while no large randomized clinical trials for percutaneous coronary intervention (PCI) are still available. Regardless of the lack of data and recommendations, the trends of performing PCI in ischemic heart failure prevailed over CABG whereas lesion complexity, chronic total occlusion and complete revascularization achievement are limiting factors. Lastly, regenerative medicine seems a promising approach for advanced heart failure enhancing cardiomyocytes proliferation, reverse remodeling, scar size reduction and cardiac function restoration.

Physiology of a Forgotten Electrolyte-Magnesium Disorders

Magnesium (Mg²⁺) is the second most common intracellular cation and the fourth most abundant element on earth. However, Mg²⁺ is a frequently overlooked electrolyte and often not measured in patients. While hypomagnesemia is common in 15% of the general population, hypermagnesemia is typically only found in preeclamptic women after Mg²⁺ therapy and in patients with ESRD. Mild to moderate hypomagnesemia has been associated with hypertension, metabolic syndrome, type 2 diabetes mellitus, CKD, and cancer. Nutritional Mg²⁺ intake and enteral Mg²⁺ absorption are important for Mg²⁺ homeostasis, but the kidneys are the key regulators of Mg²⁺ homeostasis by limiting urinary excretion to less than 4% while the gastrointestinal tract loses over 50% of the Mg²⁺ intake in the feces. Here, we review the physiological relevance of Mg²⁺, the current knowledge of Mg²⁺ absorption in the kidneys and the gut, the different causes of hypomagnesemia, and a diagnostic approach on how to assess Mg²⁺ status. We highlight the latest discoveries of monogenetic conditions causing hypomagnesemia, which have enhanced our understanding of tubular Mg²⁺ absorption. We will also discuss external and iatrogenic causes of hypomagnesemia and advances in the treatment of hypomagnesemia.

Diffuse myocardial fibrosis associates with incident ventricular arrhythmia in implantable cardioverter defibrillator recipients

Background

Diffuse myocardial fibrosis (DMF) quantified by extracellular volume (ECV) may represent a vulnerable phenotype and associate with life threatening ventricular arrhythmias more than focal myocardial fibrosis. This principle remains important because 1) risk stratification for implantable cardioverter defibrillators (ICD) remains challenging, and 2) DMF may respond to current or emerging medical therapies (reversible substrate).

Objectives

To evaluate the association between quantified by ECV in myocardium without focal fibrosis by late gadolinium enhancement (LGE) with time from ICD implantation to 1) appropriate shock, or 2) shock or anti-tachycardia pacing.

Methods

Among patients referred for cardiovascular magnetic resonance (CMR) without congenital disease, hypertrophic cardiomyopathy, or amyloidosis who received ICDs (n=215), we used Cox regression to associate ECV with incident ICD therapy.

Results

After a median of 2.9 (IQR 1.5-4.2) years, 25 surviving patients experienced ICD shock and 44 experienced shock or anti-tachycardia pacing. ECV ranged from 20.2% to 39.4%. No patient with ECV<25% experienced an ICD shock. ECV associated with both endpoints, e.g., hazard ratio 2.17 (95%CI 1.17-4.00) for every 5% increase in ECV, p=0.014 in a stepwise model for ICD shock adjusting for ICD indication, age, smoking, atrial fibrillation, and myocardial infarction, whereas focal fibrosis by LGE and global longitudinal strain (GLS) did not.

Conclusions

DMF measured by ECV associates with ventricular arrhythmias requiring ICD therapy in a dose-response fashion, even adjusting for potential confounding variables, focal fibrosis by LGE, and GLS. ECV-based risk stratification and DMF representing a therapeutic target to prevent ventricular arrhythmia warrant further investigation.

Relative Efficacy of Spironolactone, Eplerenone, and cAnRenone in patients with Chronic Heart failure (RESEARCH): a systematic review and network meta-analysis of randomized controlled trials

This study aims to assess the comparative benefit and risk profile of treatment with mineralocorticoid receptor antagonists (MRAs) with regard to all-cause mortality (primary endpoint), cardiovascular mortality, or heart failure (HF)-related hospitalization (secondary endpoints) and the safety endpoints hyperkalemia, acute renal failure, and gynecomastia in patients with chronic HF. We conducted a systematic review and network meta-analysis following PRISMA-P and PRISMA-NMA guidelines. From 16 different sources, 14 randomized controlled trials totaling 12,213 patients testing an active treatment of either spironolactone, eplerenone, or canrenone/potassium-canreonate in adults with symptomatic HF due to systolic dysfunction reporting any of the above endpoints were retained. Efficacy in comparison to placebo/standard medical care with respect to all-cause mortality was confirmed for spironolactone and eplerenone while no conclusion could be drawn for canrenone (HR 0.69 (0.62; 0.77), 0.82 (0.75; 0.91), and 0.50 (0.17; 1.45), respectively). Indirect comparisons hint a potential (non-significant) preference of spironolactone over eplerenone (HR 0.84 (0.68; 1.03)). The overall risk of bias was low to intermediate. Results for secondary endpoints as well as sensitivity analyses essentially mirrored these findings. The beta-blocker adjusted meta-analysis for the primary endpoint showed the same tendency as the unadjusted one (HR 0.39 (0.07; 2.03)). Results need to be interpreted with caution, though, as the resultant mix of patient- and study-level covariates produced unstable statistical modeling. We found no significant and systematic superiority of either MRA regarding efficacy toward all endpoints considered in both direct and indirect comparisons.

Effects of spironolactone on extrasystoles and heart rate variability in haemodialysis patients: a randomised crossover trial

BACKGROUND

Spironolactone treatment reduces mortality in haemodialysis (HD) patients. The objective of this study was to evaluate if spironolactone affects cardiac electric activity in this population.

METHODS

Participants were randomised to start with spironolactone 50 mg daily or observation (12 weeks) with subsequent washout (6 weeks) and crossover to the other intervention (12 weeks). Long-term electrocardiograms were recorded and assessed with blinding to treatment. The primary outcome was premature ventricular complexes (PVC), and secondary outcomes were atrial premature contractions (APC) and heart rate variability (HRV).

RESULTS

Thirty participants were recruited, and data for 16 participants were included in the analysis. Treatment was associated with an increase in PVCs by 9.7 [95% confidence interval (CI): 1.5 to 18] h^-1. HRV time-domain variables increased during treatment, the standard deviation of all beat-to-beat intervals by 18 (95% CI: 3.3 to 32) milliseconds (ms) and the standard deviation of the averages of beat-to-beat intervals in all 5-min segments of the entire recording by 16 (95% CI: 1.5 to 30) ms. There were no significant differences in other variables.

CONCLUSION

Spironolactone treatment increases PVCs in HD, indicating a possible proarrhythmic effect. However, improved cardiac autonomic function, as indicated by an increased HRV, may contribute to the survival benefit from spironolactone treatment in HD patients.

Clinical Care Recommendations for Cardiologists Treating Adults With Myotonic Dystrophy

Myotonic dystrophy is an inherited systemic disorder affecting skeletal muscle and the heart. Genetic testing for myotonic dystrophy is diagnostic and identifies those at risk for cardiac complications. The 2 major genetic forms of myotonic dystrophy, type 1 and type 2, differ in genetic etiology yet share clinical features. The cardiac management of myotonic dystrophy should include surveillance for arrhythmias and left ventricular dysfunction, both of which occur in progressive manner and contribute to morbidity and mortality. To promote the development of care guidelines for myotonic dystrophy, the Myotonic Foundation solicited the input of care experts and organized the drafting of these recommendations. As a rare disorder, large scale clinical trial data to guide the management of myotonic dystrophy are largely lacking. The following recommendations represent expert consensus opinion from those with experience in the management of myotonic dystrophy, in part supported by literature-based evidence where available.

Update on antiarrhythmic drug pharmacology

Cardiac arrhythmias constitute a major public health problem. Pharmacological intervention remains mainstay to their clinical management. This, in turn, depends upon systematic drug classification schemes relating their molecular, cellular, and systems effects to clinical indications and therapeutic actions. This approach was first pioneered in the 1960s Vaughan-Williams classification. Subsequent progress in cardiac electrophysiological understanding led to a lag between the fundamental science and its clinical translation, partly addressed by The working group of the European Society of Cardiology (1991), which, however, did not emerge with formal classifications. We here utilize the recent Revised Oxford Classification Scheme to review antiarrhythmic drug pharmacology. We survey drugs and therapeutic targets offered by the more recently characterized ion channels, transporters, receptors, intracellular Ca²⁺ handling, and cell signaling molecules. These are organized into their strategic roles in cardiac electrophysiological function. Following analysis of the arrhythmic process itself, we consider (a) pharmacological agents directly targeting membrane function, particularly the Na⁺ and K⁺ ion channels underlying depolarizing and repolarizing events in the cardiac action potential. (b) We also consider agents that modify autonomic activity that, in turn, affects both the membrane and (c) the Ca²⁺ homeostatic and excitation-contraction coupling processes linking membrane excitation to contractile activation. Finally, we consider (d) drugs acting on more upstream energetic and structural remodeling processes currently the subject of clinical trials. Such systematic correlations of drug actions and arrhythmic mechanisms at different molecular to systems levels of cardiac function will facilitate current and future antiarrhythmic therapy.

Serum endotrophin levels in patients with heart failure with reduced and mid-range ejection fraction

BACKGROUND

Endotrophin, a type VI collagen cleavage product, has fibrosis, and insulin resistance effects. Type VI collagen also plays a role in cardiac fibrosis. In this study, we aimed to investigate the role of endotrophin in the pathogenesis of cardiac fibrosis by determining its levels in patients with heart failure with reduced and mid-range ejection fraction (EF). We also aimed to determine the possible association between endotrophin and treatment that prevents ventricular fibrosis.

METHODS

Sixty patients with heart failure with reduced and mid-range EF and 27 volunteers with no cardiac failure were included in this study. In both groups, biochemical tests, EF, and endotrophin levels were measured. ELISA was performed for the determination of endotrophin levels.

RESULTS

When compared with the control group, there was no significant difference for endotrophin levels in the patient group (p = .35). Participants in the study were divided into two groups according to their EFs, 40% and less, and 40-49%. They were classified according to their use of renin-angiotensin-aldosterone system (RAAS) blocking drugs. Endotrophin levels were significantly lower in patients with mid-range EFs between 40 and 49% (p = .03) using RAAS blockers.

CONCLUSION

This study is the first to evaluate the relationship between endotrophin and heart failure. Endotrophin levels were found to be low in patients with heart failure with mid-range EF who were using RAAS blockers. This suggests that RAAS blockers may influence endotrophin levels and thus could have a role in the prevention of remodelling.

Medical Therapy for Heart Failure Caused by Ischemic Heart Disease

Patients with heart failure (HF) syndromes have been categorized as those with reduced ejection fraction (EF) or preserved EF (HFpEF), and ischemia plays a key role in both types. HF remains a major cause of morbidity and mortality worldwide, and with the aging of our population this burden continues to rise, predominantly as a result of hospitalizations for HFpEF. Patients with obstructive coronary artery disease more likely have HF with reduced EF, rather than HFpEF, secondary to acute ischemic injury resulting in myocardial infarction, and large outcomes trials of treatments with neurohumoral inhibition have documented reduced adverse outcomes. In contrast, similar treatments in patients with HFpEF have not proven beneficial. This therapeutic dilemma may be attributed, in part, to heterogeneity in the underlying pathophysiology with different systemic and myocardial signaling pathways, despite similar clinical presentations and findings, in patients with HFpEF. Also, emerging evidence indicates that impaired myocardial perfusion and inflammation secondary to multiple comorbidities are key mechanisms in HFpEF. We will thoroughly review the role of ischemic heart disease in the pathogenesis of HF with reduced EF and HFpEF, and discuss the medical management strategies available for these conditions.

Comparison of tolvaptan treatment between patients with the SIADH and congestive heart failure: a single-center experience

BACKGROUND/AIMS

Tolvaptan is a very effective treatment for hypervolemic or euvolemic hyponatremia. We compared the clinical efficacy of and response to tolvaptan in patients with the syndrome of inappropriate antidiuretic hormone secretion (SIADH) and congestive heart failure (CHF).

METHODS

We retrospectively reviewed the medical records of 50 patients (SIADH, n = 30; CHF, n = 20) who were prescribed tolvaptan between July 2013 and October 2015. Tolvaptan was prescribed when the serum sodium level was < 125 mmol/L and the standard treatment failed. Normonatremia was defined as a serum sodium level of > 135 mmol/L.

RESULTS

After the initiation of tolvaptan therapy, there was an immediate response in the urine volume and serum sodium level in all patients. The improvements in the urine volume and serum sodium concentration were highest within the first 24 hours of treatment. In addition, the mean change in the serum sodium level during the first 24 hours was significantly higher in patients with SIADH than in those with CHF (∆Na, 9.9 ± 4.5 mmol/L vs. 6.9 ± 4.4 mmol/L, respectively; p = 0.025). Also, the mean maintenance dose was lower, and the total duration of tolvaptan use was slightly shorter in the SIADH group than CHF group (21.5 ± 14.9 days vs. 28.0 ± 20.1 days, p = 0.070).

CONCLUSIONS

The early response to tolvaptan treatment was better in patients with SIADH than in those with CHF. Thus, the tolvaptan treatment strategy should be differed between patients with SIADH and those with CHF.

Employing Extracellular Volume Cardiovascular Magnetic Resonance Measures of Myocardial Fibrosis to Foster Novel Therapeutics

Quantifying myocardial fibrosis (MF) with myocardial extracellular volume measures acquired during cardiovascular magnetic resonance promises to transform clinical care by advancing pathophysiologic understanding and fostering novel therapeutics. Extracellular volume quantifies MF by measuring the extracellular compartment depicted by the myocardial uptake of contrast relative to plasma. MF is a key domain of dysfunctional but viable myocardium among others (eg, microvascular dysfunction and cardiomyocyte/mitochondrial dysfunction). Although anatomically distinct, these domains may functionally interact. MF represents pathological remodeling in the heart associated with cardiac dysfunction and adverse outcomes likely mediated by interactions with the microvasculature and the cardiomyocyte. Reversal of MF improves key measures of cardiac dysfunction, so reversal of MF represents a likely mechanism for improved outcomes. Instead of characterizing the myocardium as homogenous tissue and using important yet still generic descriptors, such as thickness (hypertrophy) and function (diastolic or systolic), which lack mechanistic specificity, paradigms of cardiac disease have evolved to conceptualize myocardial disease and patient vulnerability based on the extent of disease involving its various compartments. Specifying myocardial compartmental involvement may then implicate cellular/molecular disease pathways for treatment and targeted pharmaceutical development and above all highlight the role of the cardiac-specific pathology in heart failure among myriad other changes in the heart and beyond. The cardiology community now requires phase 2 and 3 clinical trials to examine strategies for the regression/prevention of MF and eventually biomarkers to identify MF without reliance on cardiovascular magnetic resonance. It seems likely that efficacious antifibrotic therapy will improve outcomes, but definitive data are needed.

Third-generation Mineralocorticoid Receptor Antagonists: Why Do We Need a Fourth?

The first mineralocorticoid receptor (MR) antagonist, spironolactone, was developed almost 60 years ago to treat primary aldosteronism and pathological edema. Its use waned in part because of its lack of selectivity. Subsequently, knowledge of the scope of MR function was expanded along with clinical evidence of the therapeutic importance of MR antagonists to prevent the ravages of inappropriate MR activation. Forty-two years elapsed between the first and MR-selective second generation of MR antagonists. Fifteen years later, despite serious shortcomings of the existing antagonists, a third-generation antagonist has yet to be marketed. Progress has been slowed by the lack of appreciation of the large variety of cell types that express the MR and its diverse cell-type-specific actions, and also its unique complex interaction actions at the molecular level. New MR antagonists should preferentially target the inflammatory and fibrotic effects of MR and perhaps its excitatory effects on sympathetic nervous system, but not the renal tubular epithelium or neurons of the cortex and hippocampus. This review briefly describes efforts to develop a third-generation MR antagonist and why fourth generation antagonists and selective agonists based on structural determinants of tissue and ligand-specific MR activation should be contemplated.

Aldosterone and cardiovascular remodelling: focus on myocardial failure

Heart failure is a clinical syndrome that may result from different disease states or conditions that injure the myocardium. The activation of circulating neurohormones, particularly aldosterone, may play a pivotal role in left ventricular (LV) remodelling. The Randomized Aldactone Evaluation Study and Eplerenone Post-Acute Myocardial Infarction Heart Failure Efficacy and Survival trial have emphasised the clinical importance of aldosterone. This review addresses some of the proposed mechanisms of LV remodelling in heart failure.

Beneficial Effect of Eplerenone on Cardiac Remodelling and Electrical Properties of the Failing Heart

Introduction. The effect of chronic administration of eplerenone on cardiac remodelling and electrical properties was investigated in the failing heart of cardiomyopathic hamsters (TO-2) at five months of age.

Materials and Methods. Two-month-old hamsters were treated with eplerenone (200 mg/kg/day) administered into the chow for a period of three months. Measurements of membrane potential were performed with intracellular microelectrodes connected to a high impedance DC amplifier. The thickness of the ventricular wall as well as the area of fibrosis were measured. To investigate the influence of eplerenone on the electrogenic sodium pump myocytes were isolated from the ventricle and the pump current density was whole cell clamp configuration. measured in voltage clamped cells using the whole cell clamp configuration

Results. The results indicated that: 1) the width of the left and right ventricular wall was significantly reduced; 2) the heart weight/body weight ratio was decreased by 38±2.4% (n=24 P ) (p<0.05); 3) the fibrotic area in the left ventricle (LV) was reduced by 12.6±2% (n=25) (p<0.05); 4) the incidence of cardiac arrhythmias was decreased from 58±3.8% (n=20) in the control to 40±4.1% (n=20) (p<0.05) in animals treated with eplerenone. Moreover, a significant reduction in the dispersion of the QT interval was found with the drug; 5) eplerenone increased the resting potential of ventricular fibres from 64.3±1.5 mV to 73.4±1.4 mV (n=30) (p<0.05), an effect related to the activation of an electrogenic sodium pump. The conduction velocity, in longitudinal direction, was enhanced from 50±2.2 cm/s (n=10) in the controls to 59±2.4 cm/s (n=13) (p<0.05) in animals treated with eplerenone.

Conclusions. Eplerenone reduces cardiac remodelling, the incidence of cardiac arrhythmias and improves impulse propagation, an effect in part related to the antifibrotic effect of the drug but also to the activation of the electrogenic sodium pump.

Aldosterone Antagonism in an Inflammatory State: Evidence for Myocardial Protection

Introduction. Chagas' disease is one of the most important causes of dilated cardiomyopathy in South and Central America. It is an inflammatory cardiomyopathy. We wanted to investigate whether it could have the same response to aldosterone antagonism as demonstrated before in other dilated cardiomyopathies.

Objective. To evaluate the role of spironolactone in myocardial remodelling in a Chagas' cardiomyopathy model.

Material and Methods. We studied 60 Sirius Hamsters divided into: control (C) infected (Inf) and Inf plus spironolactone (Infsp, 40 mg/kg/day) groups, for 11 months. Echocardiography with colour doppler was performed. Left ventricular end diastolic diameter (LVEDD), fractional shortening (FS) and corrected isovolumic relaxation time (IRT) were evaluated, as well as interstitial collagen volume fraction (ICVF) and myocardial inflammation.

Result. The results demonstrated that survival was improved by use of spironolactone in the chronic phase (p<0.04). Body weight (BW) was C:190 g, Inf:167 g*, Infsp:198 g (*p<0.05, compared to C and Infsp), LVEDD/BW was C:0.31, Inf: 0.35*, Infsp: 0.29 (*p<0.05, compared to C and Infsp), FS was C:38, Inf: 35.5, Infsp: 38 (with no statistical difference) and IRT was C: 23 msec, Inf: 26 msec*, Infsp: 22 msec (p<0.05, compared to C and Infsp). ICVF (%) was attenuated at LV (C: 0.34±0.1, Inf: 1.75±0.7*†, Infsp: 0.95±0.2*; *p<0.05, †p<0.05).

Conclusion. Spironolactone attenuated the myocardial remodelling in Chagas' cardiomyopathy, reduced mortality during the chronic phase and reduced inflammatory infiltration.

Circulating Procollagen Type III N-Terminal Peptide and Mortality Risk in African Americans With Heart Failure

BACKGROUND

Procollagen type III N-terminal peptide (PIIINP) is a biomarker of cardiac fibrosis that is associated with heart failure prognosis in whites. Its prognostic significance in African Americans is unknown. We sought to determine whether PIIINP is associated with outcomes in African Americans with heart failure.

METHODS AND RESULTS

Blood was collected from 138 African Americans with heart failure for determining PIIINP and genetic ancestry, and patients were followed prospectively for death or hospitalization for heart failure. PIIINP was inversely correlated with West African ancestry (R(2) = 0.061; P = .010). PIIINP > 4.88 ng/mL was associated with all-cause mortality on univariate (hazard ratio [HR] 4.9, 95% confidence interval [CI] 2.2-11.0; P < .001) and multivariate (HR 5.8; 95% CI 1.9-17.3; P = .002) analyses over a median follow-up period of 3 years. We also observed an increased risk for the combined outcome of all-cause mortality or hospitalization for heart failure with PIIINP > 4.88 ng/mL on univariate (HR 2.6, 95% CI 1.6-5.0; P < .001) and multivariate (HR 2.4, 95% CI 1.2-4.7; P = .016) analyses.

CONCLUSIONS

High circulating PIIINP is associated with poor outcomes in African Americans with chronic heart failure, suggesting that PIIINP may be useful in identifying African Americans who may benefit from additional therapy to combat fibrosis as a means of improving prognosis.

Non-genomic effects of spironolactone and eplerenone in cardiomyocytes of neonatal Wistar rats: do they evoke cardioprotective pathways?

Mineralocorticoid receptor (MR) antagonists of aldosterone (spironolactone and eplerenone) display beneficial effects in the treatment of cardiopathies; however, many of these responses are independent of this antagonism. The mechanisms of action of these drugs are not well known; few studies have comparatively evaluated whether eplerenone as well as spironolactone display cardioprotective effects independent of the blockade of aldosterone. To study these mechanisms, which lead to cardioprotective responses, and to evaluate comparatively their effects in vitro, we have evaluated the proliferative effect of spironolactone and eplerenone in primary culture of cardiomyocytes and fibroblasts of neonatal Wistar rats in the presence and absence of aldosterone. Spironolactone and eplerenone promoted proliferation of cardiomyocyte even in the absence of aldosterone, suggesting a signaling pathway independent of the antagonism over aldosterone. Spironolactone was able to reduce the proliferation of fibroblasts and to reverse the proliferation promoted by aldosterone, which was also displayed by eplerenone. To elucidate the biochemical pathways evoked by these drugs, we sought to analyze Ca(2+), cAMP, and cGMP, and the activity of PKC and ERK1/2. Spironolactone and eplerenone increased the levels of Ca(2+), cGMP and activity of ERK 1/2, and reversed the action of aldosterone on the activity of PKC and ERK1/2. Interestingly, only spironolactone increased the levels of cAMP. Our data support the fact that in addition to aldosterone, both spironolactone and eplerenone display rapid responses (non-genomic) such as an increase on cAMP, Ca(2+), and cGMP by spironolactone, and Ca(2+) and cGMP by eplerenone. We have observed a more consistent cardioprotection promoted by spironolactone; however, these effects have yet to be tested clinically. Therefore, our data show that these drugs do not only act as an antagonist of MR, but could lead to a new pharmacological classification of these drugs.

The role of aldosterone in heart failure and the clinical benefits of aldosterone blockade

Aldosterone has a variety of detrimental effects on the heart and vasculature and is increasingly recognized as an important target in chronic heart failure, as illustrated by the Randomized Aldactone Evaluation Study. In this article, the evidence supporting the cardiovascular effects of aldosterone in humans and the proven benefits of aldosterone-receptor antagonists in heart failure shall be discussed.

The cardioprotective effects of mineralocorticoid receptor antagonists

Despite state-of-the-art reperfusion therapy, morbidity and mortality remain significant in patients with an acute myocardial infarction. Therefore, novel strategies to limit myocardial ischemia-reperfusion injury are urgently needed. Mineralocorticoid receptor (MR) antagonists are attractive candidates for this purpose, since several clinical trials in patients with heart failure have reported a survival benefit with MR antagonist treatment. MRs are expressed by several cells of the cardiovascular system, including cardiomyocytes, cardiac fibroblasts, vascular smooth muscle cells, and endothelial cells. Experiments in animal models of myocardial infarction have demonstrated that acute administration of MR antagonists, either before ischemia or immediately at the moment of coronary reperfusion, limits infarct size. This action appears to be independent of the presence of aldosterone and cortisol, which are the endogenous ligands for the MR. The cardioprotective effect is mediated by a nongenomic intracellular signaling pathway, including adenosine receptor stimulation, and activation of several components of the Reperfusion Injury Salvage Kinase (RISK) pathway. In addition to limiting infarct size, MR antagonists can improve scar healing when administered shortly after reperfusion and can reduce cardiac remodeling post myocardial infarction. Clinical trials are currently being performed studying whether early administration of MR antagonists can indeed improve prognosis in patients with an acute myocardial infarction, independent of the presence of heart failure.

Mineralocorticoid receptor antagonism confers cardioprotection in heart failure

The symptoms and signs constituting the congestive heart failure (CHF) syndrome have their pathophysiologic origins rooted in a salt-avid renal state mediated by effector hormones of the renin-angiotensin-aldosterone and adrenergic nervous systems. Controlled clinical trials, conducted over the past decade in patients having minimally to markedly severe symptomatic heart failure, have demonstrated the efficacy of a pharmacologic regimen that interferes with these hormones, including aldosterone receptor binding with either spironolactone or eplerenone. Potential pathophysiologic mechanisms, which have not hitherto been considered involved for the salutary responses and cardioprotection provided by these mineralocorticoid receptor antagonists, are reviewed herein. In particular, we focus on the less well-recognized impact of catecholamines and aldosterone on monovalent and divalent cation dyshomeostasis, which leads to hypokalemia, hypomagnesemia, ionized hypocalcemia with secondary hyperparathyroidism and hypozincemia. Attendant adverse cardiac consequences include a delay in myocardial repolarization with increased propensity for supraventricular and ventricular arrhythmias, and compromised antioxidant defenses with increased susceptibility to nonischemic cardiomyocyte necrosis.

New evidence for vascular interactions between aldosterone, angiotensin II and antioxidants in isolated smooth muscle cells of rats

Accumulating evidence suggests that the nongenomic cardiovascular actions of aldosterone are produced by varied cellular pathways and mediated by a multitude of messenger systems including the reactive oxygen and nitrogen species. Considering the involvement of the oxidative and nitrosative stress in the pathways leading to the activation of the angiotensin — aldosterone system, in the current study we tried to evaluate the functional interactions between aldosterone, angiotensin II and antioxidants in isolated vascular smooth muscle of aortic rings from rats. Our data provide additional arguments that the nongenomic actions of aldosterone on aortic smooth muscle cells of rats are a question of cross-talk and balance between its rapid vasoconstrictor and vasodilator effects, as result of the activation of reactive oxygen species in the first case and of nitrogen species in the second. In this way, it seems that at low ambient oxidative stress, aldosterone promotes nitric oxide (NO) production and vasodilatation, while in situations with increased oxidative stress the endothelial dysfunction and detrimental effects induced by vasoconstriction will prevail. Thus, aldosterone could be considered both “friend and foe”. This could be relevant for the ways in which aldosterone damages cardiovascular functions and could lead to significant therapeutic improvements.

Effect of spironolactone on ventricular arrhythmias in patients with left ventricular systolic dysfunction and implantable cardioverter defibrillators

AIMS/OBJECTIVES

Patients with implantable cardioverter defibrillators (ICD) often receive an adjunctive anti-arrhythmic therapy. We propose that an addition of spironolactone will reduce the number of clinically significant ventricular arrhythmias and ICD-related therapies.

METHODS AND RESULTS

In a multicentre retrospective study, 64 patients with ischaemic and non-ischaemic dilated cardiomyopathy whose left ventricular ejection fraction (LVEF) was <35% and with ICD were selected. Amongst these patients, 28 patients were on spironolactone and 36 were not taking spironolactone. The ICD interrogation data were analysed for a maximum of 12 months. Wilcoxon Rank Sum test was used to compare the study and control groups. The outcomes were: (1) the number of shocks/anti-tachycardia pacing (ATP) episodes and (2) the number of episodes of ventricular tachycardia (VT) requiring ATP, non-sustained VT (NSVT), and ventricular fibrillation (VF) over the study period. The spironolactone group had fewer monthly, VTs (P=0.027) (requiring ATP). The two groups did not differ in the number of NSVT or VF per month.

CONCLUSION

Addition of spironolactone as an adjunct to ICD therapy in patients with congestive heart failure (CHF) reduces VT requiring ATP, but does not affect NSVT or VF per month.

RETRACTED: Ventricular Ectopic Beats: An Overview of Management Considerations

Ventricular ectopic beats are commonly seen in daily clinical practice. Majority of them being asymptomatic, some can cause symptoms. In a normal heart, their occurrence is of no clinical significance. However, in the presence of an underlying heart disease, they signify a susceptibility toward more sinister arrhythmias. In some patients, they are triggered by the same mechanism as ventricular tachycardia and these can be cured by catheter ablation. Recent reports on the use of catheter ablation in cases where focal ventricular ectopics are found to trigger ventricular fibrillation. Clinical evaluation and investigations are important in assessing patients with ventricular ectopic beats so that appropriate treatment can be targeted when necessary. This article discusses the current knowledge and practice in this commonly encountered clinical problem.

Aldosterone induces electrical remodeling independent of hypertension

BACKGROUND

Treatment of heart failure patients with aldosterone antagonists has been shown to reduce the occurrence of sudden cardiac death. Therefore we aimed at determining the consequences of chronic exposure to aldosterone and the aldosterone antagonists eplerenone and spironolactone on the electrophysiological properties of the heart in a rat model.

METHODS AND RESULTS

Male Wistar rats were chronically treated (4weeks) with aldosterone (ALD) via an osmotic minipump. Spironolactone (SPI) or eplerenone (EPL) was administered with the rat chow. ALD treated animals developed left ventricular hypertrophy, prolonged QT-intervals, a higher rate of ventricular premature beats and non-sustained ventricular tachycardia despite normal blood pressure values. Spironolactone and eplerenone were both able to inhibit the alterations. Left-ventricular mRNA expressions of Kv4.2 and Kv4.3 (Ito), Kv1.5 (IKur), Kir2.1 and Kir2.3 (IK1) and of Cav1.2 (L-type Ca(2+) channel) were significantly down-regulated in ALD. Correspondingly, the protein expressions of subunits Kv1.5, Kir2.3 and Cav1.2 were significantly decreased. A diminished calcineurin activity and mRNA expression of the Aß subunit of calcineurin were found in ALD, which was insensitive to aldosterone antagonists.

CONCLUSIONS

Chronic aldosterone-overload induces blood pressure independent structural and electrical remodeling of the myocardium resulting in an increased risk for malignant ventricular arrhythmias.

The effect of aldosterone antagonists for ventricular arrhythmia: a meta-analysis

BACKGROUND

Sudden cardiac death (SCD) from cardiac arrest, one of the most common types of cardiac-related death, is most often triggered by ventricular arrhythmia (VA). It has been reported that aldosterone antagonists (AAs) have the benefit of reducing SCD in patients with heart failure (HF). It also has been indicated in animal experiments and clinical trials that AAs may have an antiarrhythmic effect.

HYPOTHESIS

AAs have an effect on VA in patients with HF or coronary artery disease.

METHODS

We searched the Cochrane Central Register of Controlled Trials, PubMed, Current Controlled Trials, and the National Research Register, and identified randomized controlled trials on the effect of AAs on VA.

RESULTS

All together, 7 trials with a total of 8635 patients were identified and extracted. AAs reduced the risk of SCD in patients with HF by 21% (relative risk [RR]: 0.79, 95% confidence interval [CI]: 0.67-0.93). AAs significantly reduced the episodes of ventricular premature complexes (mean difference 705 ± 646 episodes per 24 hours). Risk of ventricular tachycardia was reduced by 72% (RR: 0.28, 95% CI: 0.10-0.77).

CONCLUSIONS

The additional administration of AAs in patients with HF or coronary artery disease shows a benefit in reducing the risk of SCD and may also be effective for reducing episodes of ventricular premature complexes and ventricular tachycardia.

Metabolic and toxicological considerations for diuretic therapy in patients with acute heart failure

INTRODUCTION

Diuretics are widely recommended in patients with acute heart failure (AHF). However, loop diuretics predispose patients to electrolyte imbalance and hypovolemia, which in turn leads to neurohormonal activation and worsening renal function (WRF). Unfortunately, despite their widespread use, limited data from randomized clinical trials are available to guide clinicians with the appropriate management of this diuretic therapy.

AREAS COVERED

This review focuses on the current management of diuretic therapy and discusses data supporting the efficacy and safety of loop diuretics in patients with AHF. The authors consider the challenges in performing clinical trials of diuretics in AHF, and describe ongoing clinical trials designed to rigorously evaluate optimal diuretic use in this syndrome. The authors review the current evidence for diuretics and suggest hypothetical bases for their efficacy relying on the complex relationship among diuretics, neurohormonal activation, renal function, fluid and sodium management, and heart failure syndrome.

EXPERT OPINION

Data from several large registries that evaluated diuretic therapy in hospitalized patients with AHF suggest that its efficacy is far from being universal. Further studies are warranted to determine whether high-dose diuretics are responsible for WRF and a higher rate of coexisting renal disease are instead markers of more severe heart failure. The authors believe that monitoring congestion during diuretic therapy in AHF would refine the current approach to AHF treatment. This would allow clinicians to identify high-risk patients and possibly reduce the incidence of complications secondary to fluid management strategies.

Treatment of primary aldosteronism: Where are we now?

Primary aldosteronism (PA) is an important cause of secondary hypertension, is being increasingly diagnosed and may account for more than 10% of hypertensive patients, both in primary care and in referral centers. Aldosterone excess is associated with adverse cardiovascular, renal and metabolic effects that are in part hypertension-independent. Laparoscopic adrenalectomy remains the mainstay of treatment for unilateral forms of PA, whereas medical treatment is recommended for bilateral forms of PA. However, a favourable surgical outcome depends on several factors and many patients are not suitable for this treatment. On the other hand, surgery in patients considered to have bilateral PA may contribute to better blood pressure control. In this review, established and novel strategies for the management of different types of PA are discussed.

The relationship between aminoterminal propeptide of type III procollagen and heart rate variability parameters in heart failure patients: a potential serum marker to evaluate cardiac autonomic control and sudden cardiac death

BACKGROUND

Cardiac extra-cellular matrix (ECM) fibrosis plays an important role in the pathophysiology of heart failure (HF). It may provide electrical heterogeneity and a substrate for arrhythmogenicity, which may cause sudden cardiac death (SCD).

METHODS

Twenty-one patients with manifestations of HF and a left ventricular ejection fraction (LVEF) ≤50% were enrolled. The median age was 62 years and median LVEF was 33%. Time- and frequency-domain analysis of heart rate variability (HRV) on 24 h ambulatory electrocardiography recording was assessed. Serum markers of ECM turnover including type I and III aminoterminal propeptide of procollagen (PINP and PIIINP), matrix metalloproteinase-2 and -9 (MMP-2 and MMP-9), and tissue inhibitor of metalloproteinase-1 (TIMP-1) were analyzed.

RESULTS

The serum PIIINP concentration was correlated significantly with standard deviation of all normal to normal R-R intervals (SDNN) (r=-0.722, p=<0.001), percentage of adjacent NN interval differences >50 ms (pNN50) (r=-0.528, p=0.014), percentage of adjacent NN interval differences >20 ms (pNN20) (r=-0.545, p=0.002), very low frequency (VLF) (r=-0.490, p=0.024), low frequency (LF) (r=-0.491, p=0.024), and high frequency (HF) (r=-0.513, p=0.018). PINP, MMP-2, -9, TIMP-1 were not correlated with time- and frequency-domain analysis of HRV.

CONCLUSIONS

PIIINP was significantly correlated with time- and frequency-domain analysis of HRV in HF patients. PIIINP is a potential serological marker to evaluate cardiac autonomic control and risk of SCD in HF patients.

Update on Renin-Angiotensin-aldosterone blockade in heart failure

There is convincing evidence that the renin-angiotensin-aldosterone system (RAAS) plays an important role in heart failure (HF), from the events that result in its inception through advanced disease. In particular, RAAS activation is one of the major pathways involved in maladaptive cardiac remodeling, a process that results in progressive cardiac dysfunction. Not surprisingly, strategies targeting the RAAS have substantial benefits in HF. These therapies, which include angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and aldosterone receptor antagonists, have emerged as cornerstones of HF therapy, particularly in patients with systolic dysfunction. Their role in HF with preserved ejection fraction, however, is less certain. New information and approaches targeting RAAS activation continue to emerge. Direct renin inhibitors are hypothesized to have beneficial effects in HF, but further studies are needed to evaluate their efficacy.

Role of drug therapy for sustained ventricular tachyarrhythmias

Antiarrhythmic drug therapy, broadly defined, is the mainstay of treatment and prevention of ventricular tachycardia (VT)/ventricular fibrillation (VF), which can lead to sudden death. This article evaluates the evidence for and appropriate use of class I antiarrhythmic drugs, class III antiarrhythmic drugs, beta-blockers, nondihydropyridine calcium-channel blockers, statins, angiotensin enzyme inhibitors, angiotensin receptor blockers, aldosterone blockers, and digoxin for antiarrhythmic benefits in patients who have a propensity for VT/VF and therefore are at risk of sudden death.

Corticosteroids and redox potential modulate spontaneous contractions in isolated rat ventricular cardiomyocytes

The mineralocorticoid receptor has been implicated in the development of several cardiac pathologies and could participate in the high incidence of lethal ventricular arrhythmias associated with hyperaldosteronism. We have observed previously that aldosterone markedly increases in vitro the rate of spontaneous contractions of isolated neonate rat ventricular myocytes, a putative proarrhythmogenic condition if occurring in vivo. In the present study, we investigated the effect of glucocorticoids, the involvement of the glucocorticoid receptor, and the modulation of their action by redox agents. Aldosterone and glucocorticoids exerted in vitro a similar, concentration-dependent chronotropic action on cardiomyocytes, which was mediated by both the mineralocorticoid and glucocorticoid receptors. However, the relative contribution of each receptor was different for each agonist, at each concentration. Angiotensin II induced a similar response that was entirely dependent on the activity of the glucocorticoid receptor. Corticosteroid action was modulated by the redox state of the cells, with oxidation increasing the response while reducing conditions partially preventing it. When only the mineralocorticoid receptor was functionally present in the cells, oxidation was necessary to reveal glucocorticoid action, but no obvious competition with mineralocorticoids was observed when both agonists where simultaneously present. In conclusion, corticosteroids exert a strong chronotropic action in ventricular cardiomyocytes, mediated by both the mineralocorticoid and glucocorticoid receptors and modulated by the redox state of the cell. This phenomenon is believed to be because of cell electric remodeling and could contribute in vivo to the deleterious consequence of inappropriate receptor activation, leading to increased susceptibility of patients to arrhythmias.

A propensity-matched study of low serum potassium and mortality in older adults with chronic heart failure

OBJECTIVE

Most HF patients are older adults, yet the associations of low serum potassium and outcomes in these patients are unknown. We studied the effect of low serum potassium in a propensity-matched population of elderly HF patients.

METHODS

Of the 7788 patients in the Digitalis Investigation Group trial, 4036 were >or=65 years. Of these, 3598 had data on baseline serum potassium and 324 with potassium >or=5 mEq/L were excluded. Remaining patients were categorized into low (<4 mEq/L; n=590) and normal (4-4.9 mEq/L; n=2684) potassium groups. Propensity scores for low-potassium, calculated for each patient, were used to match 561 low-potassium and 1670 normal-potassium patients. Association of low potassium and outcomes were assessed using matched Cox regression analyses.

RESULTS

Patients had a mean (+/-SD) age of 72 (+/-6) years, 29% were women and 12% were non-whites. Of the 561 low-potassium patients, 500 had low-normal (3.5-3.9 mEq/L) potassium. All-cause mortality occurred in 37% (rate, 1338/10,000 person-years) normal-potassium and 43% (rate, 1594/10,000 person-years) low-potassium patients (hazard ratio {HR} for low-potassium, 1.22; 95% confidence interval {CI}, 1.04-1.44; p=0.014). Low-normal (3.5-3.9 mEq/L) potassium levels had a similar association with mortality (HR, 1.19, 95% CI, 1.00-1.41, p=0.049). Low (HR, 1.10; 95% CI, 0.96-1.25; p=0.175) or low-normal (HR=1.09, 95% CI=0.95-1.25, p=0.229) serum potassium levels were not associated with all-cause hospitalization.

CONCLUSIONS

In a propensity-matched population of elderly ambulatory chronic HF patients, well-balanced in all measured baseline covariates, low and low-normal serum potassium were associated with increased mortality but had no association with hospitalization.

Aldosterone and end-organ damage

Aldosterone concentrations are inappropriately high in many patients with hypertension, as well as in an increasing number of individuals with metabolic syndrome and sleep apnoea. A growing body of evidence suggests that aldosterone and/or activation of the MR (mineralocorticoid receptor) contributes to cardiovascular remodelling and renal injury in these conditions. In addition to causing sodium retention and increased blood pressure, MR activation induces oxidative stress, endothelial dysfunction, inflammation and subsequent fibrosis. The MR may be activated by aldosterone and cortisol or via transactivation by the AT(1) (angiotenin II type 1) receptor through a mechanism involving the EGFR (epidermal growth factor receptor) and MAPK (mitogen-activated protein kinase) pathway. In addition, aldosterone can generate rapid non-genomic effects in the heart and vasculature. MR antagonism reduces mortality in patients with CHF (congestive heart failure) and following myocardial infarction. MR antagonism improves endothelial function in patients with CHF, reduces circulating biomarkers of cardiac fibrosis in CHF or following myocardial infarction, reduces blood pressure in resistant hypertension and decreases albuminuria in hypertensive and diabetic patients. In contrast, whereas adrenalectomy improves glucose homoeostasis in hyperaldosteronism, MR antagonism may worsen glucose homoeostasis and impairs endothelial function in diabetes, suggesting a possible detrimental effect of aldosterone via non-genomic pathways.

Drug Insight: aldosterone-receptor antagonists in heart failure—the journey continues

Aldosterone is an important mediator in the pathogenesis of heart failure, and increased plasma aldosterone levels are associated with a poor prognosis. Aldosterone-receptor blocking drugs can slow the progression of left ventricular remodeling and reduce the occurrence of sudden cardiac death. Two widely publicized clinical trials provide data demonstrating survival benefits with spironolactone and eplerenone in chronic and postinfarction heart failure. The publication of these trials has generated widespread enthusiasm for spironolactone and eplerenone, leading to the more frequent and sometimes unbridled use of these drugs in the medical community. We herein describe the likely mechanisms of action of aldosterone-receptor antagonists, discuss the existing clinical evidence supporting their use, and provide practical advice on their use in the management of patients with heart failure.

Spironolactone Reduced Arrhythmia and Maintained Magnesium Homeostasis in Patients With Congestive Heart Failure

BACKGROUND

Patients with congestive heart failure (CHF) often have increased aldosterone activity that leads to hypomagnesemia. Hypomagnesemia can induce arrhythmias, an important cause of death in patients with CHF. We determined whether the aldosterone receptor antagonist spironolactone improved magnesium homeostasis and reduced arrhythmias in patients with CHF.

METHODS AND RESULTS

We randomized 116 consecutive patients with CHF into placebo control group (n = 58) and spironolactone group (20 mg daily, n = 58) in addition to conventional therapy. Plasma magnesium concentration (PMC), erythrocyte magnesium concentration (EMC), and erythrocyte magnesium efflux were not different between the 2 groups of patients before treatment. Compared with control patients, patients treated with spironolactone for 6 months had increased PMC and EMC and decreased erythrocyte magnesium efflux. Patients on spironolactone therapy also had a marked decrease of 24-hour mean heart rate, ventricular and atrial premature beats, and the risk of atrial fibrillation/flutter. Pooled data from the 116 patients showed that patients with a higher EMC or a lower sodium-dependent erythrocyte magnesium efflux had a slower heart rate, fewer ventricular premature beats, and a lower risk of atrial fibrillation/flutter.

CONCLUSIONS

Our results suggest that reducing cellular magnesium efflux and loss may contribute to the spironolactone-reduced arrhythmias in patients with CHF.

Effects of aldosterone receptor blockade in patients with mild-moderate heart failure taking a beta-blocker

AIMS

Spironolactone improves prognosis in severe heart failure (HF). We investigated its effects in patients with mild-moderate HF treated with an ACE inhibitor and beta-blocker.

METHODS AND RESULTS

Randomised, double-blind, parallel-group, 3-month comparison of placebo and spironolactone (25 mg daily) in 40 patients in New York Heart Association (NYHA) class I (20%), II (70%) or III (10%), with a left ventricular ejection fraction of <40%. The mean (standard error) changes from baseline in the spironolactone and placebo groups were, respectively: i) B-type natriuretic peptide (BNP) -53.4(22.2) pg/mL and +3.3(12.1) pg/mL, P=0.04, ii) pro-collagen type III N-terminal amino peptide (PIIINP) -0.6(0.2) micromol/L and +0.02(0.2) micromol/L, P=0.02 and iii) creatinine +10.7(3.2) micromol/L and -0.3(2.6) micromol/L, P=0.01. Compared with placebo, spironolactone therapy was associated with a reduction in self-reported health-related quality of life: change in visual analog score: -6 (3) vs. +6 (4); P=0.01. No differences were observed on other biochemical, neurohumoral, exercise and autonomic function assessments.

CONCLUSION

In patients with mild-moderate HF, spironolactone reduced neurohumoral activation (BNP) and a marker of collagen turnover (PIIINP) but impaired renal function and quality of life. The benefit-risk ratio of aldosterone blockade in mild HF is uncertain and requires clarification in a large randomised trial.

Drospirenone for Oral Contraception and Hormone Replacement Therapy

The use of combined estrogen/progesterone has been shown to result in an increased cardiovascular risk in randomised double-blinded trials. However, these studies used oral progestogen (progestin) preparations, which lack anti-mineralocorticoid activity and have suboptimal anti-androgenic activity compared with progesterone. Drospirenone is a unique progestogen that has clinically been shown to have anti-mineralocorticoid/anti-androgenic effects. Drospirenone in combination with estrogen is currently being used for oral contraception and hormone replacement therapy, and has been shown to have favourable effects on a number of cardiovascular risk factors. Our review of the literature suggests that because of its anti-mineralocorticoid effects, drospirenone in conjunction with estrogen may prevent the development of cardiovascular disease in both pre- and post-menopausal women.