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

Incidence and progression of atrial fibrillation in patients with and without heart failure using mineralocorticoid receptor antagonists: a meta-analysis

BACKGROUND

Mineralocorticoid receptor antagonists (MRAs) have emerged as potential therapy to target the underlying arrhythmogenic substrate in atrial fibrillation (AF). Nevertheless, there have been inconsistent results on the impact of MRAs on AF.

OBJECTIVE

We sought to evaluate the effect of MRAs on AF incidence and progression in patients with and without heart failure.

METHODS

Electronic databases were searched up to September, 2022 for randomized controlled trials (RCTs) that evaluated MRA use and reported AF outcomes. Primary outcome was a composite of new-onset or recurrent AF. Safety outcomes included hyperkalemia and gynecomastia risks. A random-effects meta-analysis estimated pooled odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

12 RCTs, comprising 11,419 patients treated with various MRAs were included [5960 (52%) on MRA]. On follow-up (6-39 months), 714 (5.5%) patients developed AF. MRA therapy was associated with a 32% reduction in the risk of new-onset or recurrent AF [OR 0.68 (95% CI 0.51-0.92), I2 = 40%]. On subgroup analysis, the greatest benefit magnitude was demonstrated in reducing AF recurrence [OR 0.50 (95% CI 0.30-0.83)] and among patients with left ventricular dysfunction [OR 0.59 (95% CI 0.40-0.85)]. Gynecomastia, but not hyperkalemia, was associated with MRA use. Meta-regression analysis demonstrated that therapy duration was a significant interaction factor driving the effect size (Pinteraction = 0.013).

CONCLUSION

MRA use is associated with a reduction in AF risk, especially AF progression. A prominent effect is seen in patients with heart failure, further augmented by therapy duration. Prospective trials are warranted to evaluate MRA use as upstream therapy for preventing this common arrhythmia.

Pharmacotherapy in patients with heart failure with reduced ejection fraction: A systematic review and meta-analysis

BACKGROUND

Angiotensin receptor neprilysin inhibitors (ARNIs), angiotensin-converting enzyme inhibitors (ACEIs), angiotensin receptor blockers (ARBs), β-blockers (BBs), and mineralocorticoid receptor antagonists (MRAs) are the cornerstones in treating heart failure with reduced ejection fraction (HFrEF). Sodium-glucose cotransporter 2 inhibitors (SGLT-2is) are included in HFrEF treatment guidelines. However, the effect of SGLT-2i and the five drugs on HFrEF have not yet been systematically evaluated.

METHODS

PubMed, Embase, and the Cochrane Library were searched for randomized controlled trials (RCTs) from inception dates to September 23, 2022. Additional trials from previous relevant reviews and references were also included. The primary outcomes were changes in left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter/dimension (LVEDD), left ventricular end-systolic diameter/dimension (LVESD), left ventricular end-diastolic volume (LVEDV), and left ventricular end-systolic volume (LVESV), left ventricular end-systolic volume index (LVESVI), and left ventricular end-diastolic volume index (LVEDVI). Secondary outcomes were New York Heart Association (NYHA) class, 6-min walking distance (6MWD), B-type natriuretic peptide (BNP) level, and N-terminal pro-BNP (NT-proBNP) level. The effect sizes were presented as the mean difference (MD) with 95% confidence interval (CI).

RESULTS

We included 68 RCTs involving 16,425 patients. Compared with placebo, ARNI + BB + MRA + SGLT-2i was the most effective combination to improve LVEF (15.63%, 95% CI: 9.91% to 21.68%). ARNI + BB + MRA + SGLT-2i (5.83%, 95% CI: 0.53% to 11.14%) and ARNI + BB + MRA (3.83%, 95% CI: 0.72% to 6.90%) were superior to the traditional golden triangle "ACEI + BB + MRA" in improving LVEF. ACEI + BB + MRA + SGLT-2i was better than ACEI + BB + MRA (-8.05 mL/m2, 95% CI: -14.88 to -1.23 mL/m2) and ACEI + BB + SGLT-2i (-18.94 mL/m2, 95% CI: -36.97 to -0.61 mL/m2) in improving LVEDVI. ACEI + BB + MRA + SGLT-2i (-3254.21 pg/mL, 95% CI: -6242.19 to -560.47 pg/mL) was superior to ARB + BB + MRA in reducing NT-proBNP.

CONCLUSIONS

Adding SGLT-2i to ARNI/ACEI + BB + MRA is beneficial for reversing cardiac remodeling. The new quadruple drug "ARNI + BB + MRA + SGLT-2i" is superior to the golden triangle "ACEI + BB + MRA" in improving LVEF.

REGISTRATION

PROSPERO; No. CRD42022354792.

Mineralocorticoid receptor antagonists and atrial fibrillation: a meta-analysis of clinical trials

BACKGROUND AND AIMS

Mineralocorticoid receptor antagonists (MRAs) improve cardiovascular outcomes in a variety of settings. This study aimed to assess whether cardioprotective effects of MRAs are modified by heart failure (HF) and atrial fibrillation (AF) status and to study their impact on AF events.

METHODS

MEDLINE, Embase, and Cochrane Central databases were searched to 24 March 2023 for randomized controlled trials evaluating the efficacy of MRAs as compared with placebo or usual care in reducing cardiovascular outcomes and AF events in patients with or at risk for cardiovascular diseases. Random-effects models and interaction analyses were used to test for effect modification.

RESULTS

Meta-analysis of seven trials (20 741 participants, mean age: 65.6 years, 32% women) showed that the efficacy of MRAs, as compared with placebo, in reducing a composite of cardiovascular death or HF hospitalization remains consistent across patients with HF [risk ratio = 0.81; 95% confidence interval (CI): 0.67-0.98] and without HF (risk ratio = 0.84; 95% CI: 0.75-0.93; interaction P = .77). Among patients with HF, MRAs reduced cardiovascular death or HF hospitalization in patients with AF (hazard ratio = 0.95; 95% CI: 0.54-1.66) to a similar extent as in those without AF (hazard ratio = 0.82; 95% CI: 0.63-1.07; interaction P = .65). Pooled data from 20 trials (21 791 participants, mean age: 65.2 years, 31.3% women) showed that MRAs reduce AF events (risk ratio = 0.76; 95% CI: 0.67-0.87) in both patients with and without prior AF.

CONCLUSIONS

Mineralocorticoid receptor antagonists are similarly effective in preventing cardiovascular events in patients with and without HF and most likely retain their efficacy regardless of AF status. Mineralocorticoid receptor antagonists may also be moderately effective in preventing incident or recurrent AF events.

A Systematic Review and Meta-Analysis on Effectiveness of Mineralocorticoid Receptor Antagonists in Reducing the Risk of Atrial Fibrillation

Mineralocorticoid receptor antagonists (MRAs) are known to improve clinical outcomes in heart failure, particularly heart failure with reduced ejection fraction. However, the effect of MRAs on the incidence of and recurrence of atrial fibrillation (AF) is not well established. Therefore, databases, such as PubMed, EMBASE, and Cochrane Central, were searched from inception to September 2021 for randomized controlled trials of MRAs with AF as an outcome. Risk ratios (RRs) with 95% confidence interval (CIs) were combined using the random-effects model. A total of 10 randomized controlled trials (n = 11,356) were included. Our pooled analysis demonstrates that MRAs reduce the risk of AF occurrence by 23% compared with the control therapy (RR 0.77, 95% CI 0.65 to 0.91, p = 0.003, I2 = 40%). Subgroup analysis demonstrated that MRAs reduced the risk of both new-onset AF (RR 0.84, 95% CI 0.61 to 1.16, p = 0.28, I2 = 43%) and recurrent AF (RR 0.73, 95% CI 0.59 to 0.90, p = 0.004, I2 = 26%) similarly; p interaction = 0.48. Our meta-analysis concludes that MRAs reduce the risk of development of AF overall, with consistent effects in new-onset and recurrent AF.

An overview of mineralocorticoid receptor antagonists as a treatment option for patients with heart failure: the current state-of-the-art and future outlook

INTRODUCTION

Mineralocorticoid receptor antagonists (MRAs) improve cardiovascular outcomes in patients with heart failure. These benefits of MRAs vary in different heart failure populations based on left ventricular ejection fraction and associated comorbidities.

AREAS COVERED

We define the pharmacologic properties of MRAs and the pathophysiological rationale for their utility in heart failure. We outline the current literature on the use of MRAs in different heart failure populations, including reduced and preserved ejection fraction (HFrEF/ HFpEF), and acute heart failure decompensation. Finally, we describe the limitations of currently available data and propose future directions of study.

EXPERT OPINION

While there is strong evidence supporting the use of MRAs in HFrEF, evidence in patients with HFpEF or acute heart failure is less definitive. Comorbidities such as obesity or atrial fibrillation could be clinical modifiers of the response to MRAs and potentially alter the risk/benefit ratio in these subpopulations. Emerging evidence for new non-steroidal MRAs reveal promising preliminary results that, if confirmed in large randomized clinical trials, could favor a change in clinical practice.

The p.Pro482Ala Variant in the CNNM2 Gene Causes Severe Hypomagnesemia Amenable to Treatment with Spironolactone

Renal hypomagnesemia syndromes involving CNNM2 protein pathogenic variants are associated with variable degrees of neurocognitive dysfunction and hypomagnesemia. Here, we report a family with a novel CNNM2 p.Pro482Ala variant, presenting with overt hypomagnesemia and mild neurological involvement (autosomal dominant renal hypomagnesemia 6, HOMG6, MIM# 613882). Using a bioinformatics approach, we showed that the p.Pro482Ala amino acid substitution causes a 3D conformational change in CNNM2 structure in the cystathionin beta synthase (CBS) domain and the carboxy-terminal protein segment. A novel finding was that aldosterone inhibition with spironolactone helped to alleviate hypomagnesemia and symptoms in the proband.

Prognostic relevance of magnesium alterations in patients with a myocardial infarction and left ventricular dysfunction: insights from the EPHESUS trial

AIMS

Magnesium changes are common in myocardial infarction (MI) complicated with left ventricular systolic dysfunction (LVSD) and/or heart failure (HF). The relation between serum magnesium and clinical outcomes is insufficiently elucidated in this population.

METHODS AND RESULTS

The EPHESUS trial randomized 6632 patients to either eplerenone or placebo. Hypomagnesemia and hypermagnesemia were defined as a serum magnesium <0.66 and >1.10 mmol/L, respectively. Linear mixed models and time-dependent Cox regression analysis were used to determine the effect of eplerenone on magnesium changes and the prognostic importance of magnesium. The co-primary outcomes were all-cause mortality and a composite of cardiovascular (CV) mortality and CV hospitalization. A total of 5371 patients had a post-baseline magnesium measurement. At baseline, 231 (4.3%) patients had hypomagnesemia and 271 (5.0%) patients had hypermagnesemia. During a median follow-up of 16 months, 682 (13%) developed hypomagnesemia and 512 (9.5%) hypermagnesemia. Eplerenone treatment did not result in a different magnesium level during follow-up (P = 0.14). After covariate adjustment hypo- and hypermagnesemia were not associated with a higher risk of CV events. Magnesium levels did not modulate the effect of a high potassium (>5 mmol/L) or low potassium (<4 mmol/L) on the clinical outcome. Baseline magnesium levels did not influence the treatment effect of eplerenone (P-interaction > 0.1 for all primary and secondary endpoints).

CONCLUSION

In patients with MI complicated by LVSD or HF, magnesium alterations were not associated with clinical outcomes nor did they influence the effect of eplerenone. Serum magnesium did not modulate the effect of potassium changes on clinical outcome or the treatment effect of eplerenone.

CLINICALTRIALS.GOV IDENTIFIER

NCT00232180.

Drug-induced gynecomastia: A systematic review and meta-analysis of randomized clinical trials

OBJECTIVE

To review the evidence concerning treatment-related gynecomastia in patients taking spironolactone, antiandrogens, 5 alpha-reductase inhibitors, lipid-lowering and psychotropic drugs.

MATERIAL AND METHODS

A search of Medline and EMBASE was performed up to 30 June 2021. We included randomized controlled trials comparing the effects of a drug belonging to these classes versus placebo or versus a drug of the same class.

RESULTS

A total of 32 randomized controlled trials were included in the final review. There was an increased odds of gynecomastia in men receiving antiandrogens (OR = 17.38, 95% CI: 11.26 to 26.82; 6 trials, 9599 participants) and 5 alpha-reductase inhibitors compared to controls (OR = 1.77, 95% CI: 1.53 to 2.06; 7 series out of 6 trials, 34860 participants). The use of spironolactone in mixed gender populations was characterized by significantly higher odds of having gynecomastia compared to controls (OR = 8.39, 95% CI: 5.03 to 13.99; 14 trials, 3745 participants). No placebo-controlled trials focusing on the risk of gynecomastia in patients taking antipsychotic drugs was available, although there was a significant difference in the odds of having gynecomastia in a comparison between risperidone and quetiapine (OR = 4.32, 95% CI: 1.31 to 14.27; 3 trials, 343 participants). Limited evidence about the effects of statins on mammary glands was found.

CONCLUSIONS

Antiandrogens and to a lesser extent 5 alphareductase inhibitors and spironolactone are associated with an increased risk of developing gynecomastia. Such effect can be explained by a modification of the testosterone to estradiol ratio. Gynecomastia (and galactorrhea) associated to the use of conventional and certain atypical antipsychotics can be related to high prolactin levels.

Clinical and Genetic Approach to Renal Hypomagnesemia

Magnesium (Mg²⁺) is an important intracellular cation and essential to maintain cell function including cell proliferation, immunity, cellular energy metabolism, protein and nucleic acid synthesis, and regulation of ion channels. Consequences of hypomagnesemia affecting multiple organs can be in overt or subtle presentations. Besides detailed history and complete physical examination, the assessment of urinary Mg²⁺ excretion is help to differentiate renal from extra-renal (gastrointestinal, tissue sequestration, and shifting) causes of hypomagnesemia. Renal hypomagnesemia can be caused by an increased glomerular filtration and impaired reabsorption in proximal tubular cells, thick ascending limb of the loop of Henle or distal convoluted tubules. A combination of renal Mg²⁺ wasting, familial history, age of onset, associated features, and exclusion of acquired etiologies point to inherited forms of renal hypomagnesemia. Based on clinical phenotypes, its definite genetic diagnosis can be simply grouped into specific, uncertain, and unknown gene mutations with a priority of genetic approach methods. An unequivocal molecular diagnosis could allow for prediction of clinical outcome, providing genetic counseling, avoiding unnecessary studies or interventions, and possibly uncovering the pathogenic mechanism. Given numerous identified genes responsible for Mg²⁺ transport in renal hypomagnesemia over the past two decades, several potential and specific molecular and cellular therapeutic strategies to correct hypomagnesemia are promising.

Combination pharmacotherapies for cardiac reverse remodeling in heart failure patients with reduced ejection fraction: A systematic review and network meta-analysis of randomized clinical trials

Pharmacotherapies, including angiotensin-converting enzyme inhibitors (ACEIs), angiotensin receptor II blockers (ARBs), β-blockers (BBs), mineralocorticoid receptor antagonists (MRAs) and angiotensin receptor blocker-neprilysin inhibitor (ARNI), have played a pivotal role in reducing in-hospital and mortality in heart failure patients with reduced ejection fraction (HFrEF). However, effects of the five drug categories used alone or in combination for cardiac reverse remodeling (CRR) in these patients have not been systematically evaluated. A Bayesian network meta-analysis was conducted based on 55 randomized controlled trials published between 1989 and 2019 involving 12,727 patients from PubMed, EMBASE, Cochrane Library, and Clinicaltrials.gov. The study is registered with PROSPERO (CRD42020170457). Our primary outcomes were CRR indicators, including changes of left ventricular ejection fraction (LVEF), left ventricular end-diastolic volume (LVEDV) and end-systolic volume (LVESV), indexed LVEDV (LVEDVI) and LVESV (LVESVI), and left ventricular end-diastolic dimension (LVEDD) and end-systolic dimension (LVESD); Secondary outcomes were functional capacity comprising New York Heart Association (NYHA) class and 6-min walking distance (6MWD); cardiac biomarkers involving B type natriuretic peptide (BNP) and N-terminal pro-BNP (NT-proBNP). The effect sizes were presented as the mean difference with 95% credible intervals. According to the results, all dual-combination therapies except ACEI+ARB were significantly more associated with LVEF or NYHA improvement than placebo, ARB+BB and ARNI+BB were the top two effective dual-combinations in LVEF improvement (+7.59% [+4.27, +11.25] and +7.31% [+3.93, +10.97] respectively); ACEI+BB was shown to be superior to ACEI in reducing LVEDVI and LVESVI (-6.88 mL/m² [-13.18, -1.89] and -10.64 mL/m² [-18.73, -3.54] respectively); ARNI+BB showed superiority over ACEI+BB in decreasing the level of NT-proBNP (-240.11 pg/mL [-456.57, -6.73]). All tri-combinations were significantly more effective than placebo in LVEF improvement, and ARNI+BB+MRA ranked first (+21.13% [+14.34, +28.13]); ACEI+BB+MRA was significantly more associated with a decrease in LVEDD than ACEI (-6.57 mm [-13.10, -0.84]). A sensitivity analysis ignoring concomitant therapies for LVEF illustrated that all the five drug types except ARB were shown to be superior to placebo, and ARNI ranked first (+4.83% [+1.75, +7.99]). In conclusion, combination therapies exert more benefits on CRR for patients with HFrEF. Among them, ARNI+BB, ARB+BB, ARNI+BB+MRA and ARB+BB+MRA were the top two effective dual and triple combinations in LVEF improvement, respectively; The new "Golden Triangle" of ARNI+BB+MRA was shown to be superior to ACEI+BB+MRA or ARB+BB+MRA in LVEF improvement.

Atrial fibrosis and substrate based characterization in atrial fibrillation: Time to move forwards

Atrial fibrillation (AF) is the most commonly encountered cardiac arrhythmia in clinical practice. However, current therapeutic interventions for atrial fibrillation have limited clinical efficacy as a consequence of major knowledge gaps in the mechanisms sustaining atrial fibrillation. From a mechanistic perspective, there is increasing evidence that atrial fibrosis plays a central role in the maintenance and perpetuation of atrial fibrillation. Electrophysiologically, atrial fibrosis results in alterations in conduction velocity, cellular refractoriness, and produces conduction block promoting meandering, unstable wavelets and micro-reentrant circuits. Clinically, atrial fibrosis has also linked to poor clinical outcomes including AF-related thromboembolic complications and arrhythmia recurrences post catheter ablation. In this article, we review the pathophysiology behind the formation of fibrosis as AF progresses, the role of fibrosis in arrhythmogenesis, surrogate markers for detection of fibrosis using cardiac magnetic resonance imaging, echocardiography and electroanatomic mapping, along with their respective limitations. We then proceed to review the current evidence behind therapeutic interventions targeting atrial fibrosis, including drugs and substrate-based catheter ablation therapies followed by the potential future use of electro phenotyping for AF characterization to overcome the limitations of contemporary substrate-based methodologies.

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.

Ins and Outs: Perspectives of Inpatient Prescribing for Sacubitril/Valsartan

Heart failure is a major public health concern with a rising prevalence and significant financial detriment. Although sacubitril/valsartan was shown to reduce the risk of death and hospitalization from heart failure in a contemporary cohort, it continues to remain substantially underutilized. A recent article in the Annals highlights the evidence behind inpatient initiation of sacubitril/valsartan. We provide further considerations and summarize the evidence for inpatient initiation of other guideline directed medical therapies. Overall, there is a need to improve methods to identify ideal populations and increase utilization in those who may benefit from sacubitril/valsartan. Further research is also needed to identify the risks versus benefits among underrepresented populations (i.e., advanced heart failure, heart failure with preserved ejection fraction, in conjunction with other contemporary evidence-based therapies that can lower blood pressure, etc.).

Pharmacological management of atrial fibrillation in patients with heart failure with reduced ejection fraction: review of current knowledge and future directions

Introduction: Both heart failure with reduced ejection fraction (HFrEF) and atrial fibrillation (AF) independently cause significant morbidity and mortality. The two conditions commonly coexist and AF in the setting of HFrEF is associated with worse mortality, hospitalizations, and quality of life compared to HFrEF without AF. Despite the large burden of these conditions, there is no clear optimal management strategy for when they occur together.Areas covered: This review focuses on the pharmacological management of AF in HFrEF. Studies were identified through PubMed search of relevant keywords. The authors review key clinical trials that have influenced management strategies and guidelines. The authors focus on the classes of drugs used to treat AF for both rate and rhythm control strategies including beta-blockers, digoxin, amiodarone, and dofetilide. Additionally, the authors discuss select non-antiarrhythmic medications that affect AF in HFrEF. The authors highlight the strengths and weakness of the data supporting the use of these medications and suggest future directions.Expert opinion: The pharmacological treatment of AF in HFrEF will need further refinement alongside the emerging role of catheter ablation. Novel HF medications and antiarrhythmics offer new tools to prevent the development of AF, as well as for rate and rhythm control strategies.

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.

Associations between primary aldosteronism and diabetes, poor bone health, and sleep apnea-what do we know so far?

Primary aldosteronism (PA), the most common cause of secondary hypertension, is a well-recognized condition that can lead to cardiovascular and renal complications. PA is frequently left undiagnosed and untreated, leading to aldosterone-specific morbidity and mortality. In this review we highlight the evidence linking PA with other conditions such as (i) diabetes mellitus, (ii) obstructive sleep apnea, and (iii) bone health, along with clinical implications and proposed underlying mechanisms.

Effects of Mineralocorticoid Receptor Antagonists on Atrial Fibrillation Occurrence: A Systematic Review, Meta-Analysis, and Meta-Regression to Identify Modifying Factors

Background

Mineralocorticoid receptor antagonists (MRAs) have emerged as potential atrial fibrillation (AF) preventive therapy, but inconsistent results have been reported. We aimed to examine the effects of MRAs on AF occurrence and explore factors that could influence the magnitude of the effect size.

Methods and Results

PubMed, Embase, and Cochrane Central databases were used to search for randomized clinical trials and observational studies addressing the effect of MRAs on AF occurrence from database inception through April 03, 2018. We performed a systematic review and random effects meta‐analyses to compute odds ratios with 95% CIs. Meta‐regression was then applied to explore the sources of between‐study heterogeneity. We included 24 studies, 11 randomized clinical trials and 13 observational cohorts, representing a total number of 7914 patients (median age: 64.2 years; median left ventricular ejection fraction: 49.7%; median follow‐up: 12.0 months), 2843 (35.9%) of whom received MRA therapy. Meta‐analyses showed a significant overall reduction in AF occurrence in the MRA‐treated patients versus the control groups (15.0% versus 32.2%; odds ratio, 0.55; 95% CI, 0.44–0.70 [P<0.00001]), with the greatest benefit regarding recurrent AF episodes (odds ratio, 0.42; 95% CI, 0.31–0.59 [P<0.00001]) and with significant heterogeneity among the included studies (I²=54%; P=0.0008). Meta‐regression analyses showed that effect size was significantly associated with older studies and higher AF occurrence rate in the control groups.

Conclusions

MRAs seem to be effective in AF prevention, especially regarding recurrent AF episodes.

Initiation, Continuation, Switching, and Withdrawal of Heart Failure Medical Therapies During Hospitalization

Patients with worsening heart failure with reduced ejection fraction (HFrEF) spend a large proportion of time in the hospital and other health care facilities. The benefits of guideline-directed medical therapy (GDMT) in the outpatient setting have been shown in large randomized controlled trials. However, the decision to initiate, continue, switch, or withdraw HFrEF medications in the inpatient setting is often based on multiple factors and subject to significant variability across providers. Based on available data, in well-selected, treatment-naïve patients who are hemodynamically stable and clinically euvolemic after stabilization during hospitalization for HF, elements of GDMT can be safely initiated. Inpatient continuation of GDMT for HFrEF appears safe and well-tolerated in most hemodynamically stable patients. Hospitalization is also a potential time for switching from an angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker to sacubitril/valsartan therapy in eligible patients, and is the subject of ongoing study. Therapy withdrawal or need for dose reduction is rarely required, but if needed identifies a particularly at-risk group of patients with progressive HF. If recurrent intolerance to neurohormonal blockers is observed, these patients should be evaluated for advanced HF therapies. There is an enduring need for using the teachable moment of HFrEF hospitalization for optimal initiation, continuation, and switching of GDMT to improve post-discharge patient outcomes and the quality of chronic HFrEF care.

Mineralocorticoid Receptor Antagonism in Patients With Atrial Fibrillation: Findings From the ORBIT-AF (Outcomes Registry for Better Informed Treatment of Atrial Fibrillation) Registry

Background

Mineralocorticoid receptor antagonist (MRA) therapy may be beneficial to patients with atrial fibrillation (AF), but little is known about their use in patients with AF and subsequent outcomes.

Methods and Results

In order to better understand MRA use and subsequent outcomes, we performed a retrospective cohort study of the contemporary ORBIT‐AF (Outcomes Registry for Better Informed Treatment of Atrial Fibrillation) registry. AF progression and cardiovascular outcomes were compared using propensity‐matched Cox proportional hazards modeling according to MRA use at baseline and new MRA use at follow‐up versus patients with no MRA use. Among 7012 patients with nonpermanent AF, 320 patients were taking MRA at enrollment, and 416 patients initiated MRA use during follow‐up. The mean patient age was 72.5 years, 56.3% were men, and 70.4% had paroxysmal AF. Among all patients taking MRAs, 434 (59.0%) had heart failure, 655 (89.0%) had hypertension, and 380 (51.6%) had both. After adjustment, new MRA use was not associated with reduced AF progression (hazard ratio, 1.18; 95% confidence interval, 0.88–1.58; P=0.27) but showed a trend towards lower risk of stroke, transient ischemic attack, or systemic embolism (hazard ratio, 0.17; 95% confidence interval, 0.02–1.23; P=0.08). Results were similar for a comparison of new MRA users and baseline MRA users compared with nonusers.

Conclusions

In community‐based outpatients with AF, the majority of MRA use was for heart failure and hypertension. MRA use also trended towards lower adjusted stroke risk. Future studies should test the hypothesis that MRA use may decrease the risk of stroke in patients with AF.

SGLT2 inhibitors-induced electrolyte abnormalities: An analysis of the associated mechanisms

AIMS

Sodium-glucose co-transporter 2 (SGLT2) inhibitors are a new class of antidiabetic drugs that affect serum electrolytes levels. The aim of this review is the detailed presentation of the associated mechanisms of the SGLT2 inhibitors-induced electrolyte abnormalities.

MATERIALS AND METHODS

Eligible trials and relevant articles published in PubMed (last search in July 2017) are included in the review.

RESULTS

SGLT2 inhibitors induce small increases in serum concentrations of magnesium, potassium and phosphate. The small increase in serum phosphate concentration may result in reduced bone density and increased risk of bone fractures, mainly seen with canagliflozin, but recent meta-analyses did not show increased risk of bone fractures with SGLT2 inhibitors.

CONCLUSION

The increases in serum electrolytes levels may play a role in the cardiovascular protection that has been recently reported with empagliflozin and canagliflozin.

Mineralocorticoid receptor antagonists for heart failure: systematic review and meta-analysis

Background

Mineralocorticoid receptor antagonists (MRAs) have been associated with improved patient outcomes in patients with heart failure with reduced ejection fraction (HFrEF) but not preserved ejection fraction (HFpEF). We conducted a systematic review and meta-analysis of selective and nonselective MRAs in HFrEF and HFpEF.

Methods

We searched Cochrane Central Register of Controlled Trials, MEDLINE and EMBASE. We included randomized controlled trials (RCT) of MRAs in adults with HFpEF or HFrEF if they reported data on major adverse cardiac events or drug safety.

Results

We identified 15 studies representing 16321 patients. MRAs were associated with a reduced risk of cardiovascular death (RR 0.81 [0.75–0.87], I² 0%), all-cause mortality (RR 0.83 [0.77–0.88], I² 0%), and cardiac hospitalizations (RR 0.80 [0.70–0.92], I² 58.4%). However, an a-priori specified subgroup analysis demonstrated that these benefits were limited to HFrEF (cardiovascular death RR 0.79 [0.73–0.86], I² 0%; all-cause mortality RR 0.81 [0.75–0.87], I² 0%; cardiac hospitalizations RR 0.76 [0.64–0.90], I² 68%), but not HFpEF (all-cause mortality RR 0.92 [0.79–1.08], I² 0%; cardiac hospitalizations RR 0.91 [0.67–1.24], I² 17%). MRAs increased the risk of hyperkalemia (RR 2.03 [1.78–2.31], I² 0%). Nonselective MRAs, but not selective MRAs increased the risk of gynecomastia (RR 7.37 [4.42–12.30], I² 0% vs. RR 0.74 [0.43–1.27], I² 0%). Evidence was of moderate quality for cardiovascular death, all-cause mortality and cardiovascular hospitalizations; and high-quality for hyperkalemia and gynecomastia.

Conclusions

MRAs reduce the risk of adverse cardiac events in HFrEF but not HFpEF. MRA use in HFpEF increases the risk of harm from hyperkalemia and gynecomastia. Selective MRAs are equally effective as nonselective MRAs, without a risk of gynecomastia.

Electronic supplementary material

The online version of this article (doi:10.1186/s12872-016-0425-x) contains supplementary material, which is available to authorized users.

Impact of Aldosterone Antagonists on Sudden Cardiac Death Prevention in Heart Failure and Post-Myocardial Infarction Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background and Objectives

Sudden cardiac death (SCD) is a severe burden of modern medicine. Aldosterone antagonist is publicized as effective in reducing mortality in patients with heart failure (HF) or post myocardial infarction (MI). Our study aimed to assess the efficacy of AAs on mortality including SCD, hospitalization admission and several common adverse effects.

Methods

We searched Embase, PubMed, Web of Science, Cochrane library and clinicaltrial.gov for randomized controlled trials (RCTs) assigning AAs in patients with HF or post MI through May 2015. The comparator included standard medication or placebo, or both. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Event rates were compared using a random effects model. Prospective RCTs of AAs with durations of at least 8 weeks were selected if they included at least one of the following outcomes: SCD, all-cause/cardiovascular mortality, all-cause/cardiovascular hospitalization and common side effects (hyperkalemia, renal function degradation and gynecomastia).

Results

Data from 19,333 patients enrolled in 25 trials were included. In patients with HF, this treatment significantly reduced the risk of SCD by 19% (RR 0.81; 95% CI, 0.67–0.98; p = 0.03); all-cause mortality by 19% (RR 0.81; 95% CI, 0.74–0.88, p<0.00001) and cardiovascular death by 21% (RR 0.79; 95% CI, 0.70–0.89, p<0.00001). In patients with post-MI, the matching reduced risks were 20% (RR 0.80; 95% CI, 0.66–0.98; p = 0.03), 15% (RR 0.85; 95% CI, 0.76–0.95, p = 0.003) and 17% (RR 0.83; 95% CI, 0.74–0.94, p = 0.003), respectively. Concerning both subgroups, the relative risks respectively decreased by 19% (RR 0.81; 95% CI, 0.71–0.92; p = 0.002) for SCD, 18% (RR 0.82; 95% CI, 0.77–0.88, p < 0.0001) for all-cause mortality and 20% (RR 0.80; 95% CI, 0.74–0.87, p < 0.0001) for cardiovascular mortality in patients treated with AAs. As well, hospitalizations were significantly reduced, while common adverse effects were significantly increased.

Conclusion

Aldosterone antagonists appear to be effective in reducing SCD and other mortality events, compared with placebo or standard medication in patients with HF and/or after a MI.

Mineralocorticoid receptor antagonists and atrial fibrillation: a meta-analysis

AIMS

Aldosterone has been implicated in atrial remodelling representing a potential target for upstream therapies. Accumulating evidence suggests that mineralocorticoid receptor blockade may have favourable effects on atrial fibrillation (AF) development, although some controversial results have been published. We, therefore, conducted a meta-analysis of randomized clinical trials (RCTs) and observational studies in order to examine the protective role of mineralocorticoid receptor antagonists (MRAs) on AF.

METHODS AND RESULTS

Of the 1337 initially identified records, 3 RCTs and 2 observational studies with 3640 patients were finally analysed. The pooled analysis of the included studies demonstrated that patients treated with MRAs have 31% lower risk of AF compared with controls [relative ratio (RR): 0.69; 95% confidence interval (CI): 0.58-0.83] without any heterogeneity across the studies (I(2) = 0%). This effect was consistent across RCTs (RR: 0.72; 95% CI: 0.55-0.94) and observational studies (RR: 0.67; 95% CI: 0.53-0.84) without heterogeneity. Also, MRAs reduce the risk of AF in both heart failure (HF) (RR: 0.63; 95% CI: 0.50-0.80) and after cardiac surgery (RR: 0.77; 95% CI: 0.61-0.98). Analysing the relative impact of eplerenone and spironolactone, we showed that only eplerenone significantly reduces AF burden (RR: 0.64; 95% CI: 0.44-0.90).

CONCLUSION

Our meta-analysis suggests that MRAs may be effective in AF prevention especially in the HF setting. However, there are insufficient data for the widespread use of aldosterone antagonists solely for AF prevention. Larger RCTs with long-term follow-up in different clinical settings are needed to clarify the impact of MRAs on AF.

Magnesium in Prevention and Therapy

Magnesium is the fourth most abundant mineral in the body. It has been recognized as a cofactor for more than 300 enzymatic reactions, where it is crucial for adenosine triphosphate (ATP) metabolism. Magnesium is required for DNA and RNA synthesis, reproduction, and protein synthesis. Moreover, magnesium is essential for the regulation of muscular contraction, blood pressure, insulin metabolism, cardiac excitability, vasomotor tone, nerve transmission and neuromuscular conduction. Imbalances in magnesium status—primarily hypomagnesemia as it is seen more common than hypermagnesemia—might result in unwanted neuromuscular, cardiac or nervous disorders. Based on magnesium’s many functions within the human body, it plays an important role in prevention and treatment of many diseases. Low levels of magnesium have been associated with a number of chronic diseases, such as Alzheimer’s disease, insulin resistance and type-2 diabetes mellitus, hypertension, cardiovascular disease (e.g., stroke), migraine headaches, and attention deficit hyperactivity disorder (ADHD).

Effects of spironolactone on ventricular-arterial coupling in patients with chronic systolic heart failure and mild symptoms

BACKGROUND

Several studies demonstrated that mineralocorticoid receptor antagonists (MRAs) are able to prevent myocardial and vascular fibrosis, and left ventricular (LV) remodeling in patients with systolic chronic heart failure (HF) and mild symptoms. Ventricular-arterial coupling (VAC) should be influenced by anti-fibrotic interventions. We have assessed the effects of spironolactone on VAC and its components, aortic elastance (Ea) and end-systolic LV elastance (Ees), in patients with HF.

METHODS AND RESULTS

Changes from baseline in VAC were compared between 65 patients treated with spironolactone and 32 controls not receiving MRAs. All patients had HF, reduced LVEF with reduced LV ejection fraction (LVEF) and New York Heart Association (NYHA) functional class I-II symptoms, and underwent transthoracic echocardiography at baseline and after 6 months. VAC was estimated by the modified single-beat method as Ea/Ees. Parameters of LV function improved after 6 month treatment with spironolactone with an increase in the LVEF from 34 ± 8 to 39 ± 8 % (p < 0.001). Spironolactone increased Ees from 1.32 ± 0.38 to 1.57 ± 0.42 mmHg/mL (p < 0.001) and reduced VAC from 2.03 ± 0.59 to 1.66 ± 0.31 (p < 0.001), but did not affect Ea and V0 (LV volume at end-systolic pressure of 0 mmHg). No change in any of these parameters occurred in the control group.

CONCLUSIONS

6-month therapy with spironolactone improved VAC mainly through its effect on Ees in patients with mild HF.

Hypomagnesemia: a clinical perspective

Although magnesium is involved in a wide spectrum of vital functions in normal human physiology, the significance of hypomagnesemia and necessity for its treatment are under-recognized and underappreciated in clinical practice. In the current review, we first present an overview of the clinical significance of hypomagnesemia and normal magnesium metabolism, with a focus on renal magnesium handling. Subsequently, we review the literature for both congenital and acquired hypomagnesemic conditions that affect the various steps in normal magnesium metabolism. Finally, we present an approach to the routine evaluation and suggested management of hypomagnesemia.

Mineralocorticoid receptor antagonist in heart failure: Past, present and future perspectives

Aldosterone is involved in various deleterious effects on the cardiovascular system, including sodium and fluid retention, myocardial fibrosis, vascular stiffening, endothelial dysfunction, catecholamine release and stimulation of cardiac arrhythmias. Therefore, aldosterone receptor blockade may have several potential benefits in patients with cardiovascular disease. Mineralocorticoid receptor antagonists (MRAs) have been shown to prevent many of the maladaptive effects of aldosterone, in particular among patients with heart failure (HF). Randomized controlled trials have demonstrated efficacy of MRA in heart failure with reduced ejection fraction, both in patients with NYHA functional classes III and IV and in asymptomatic and mildly symptomatic patients (NYHA classes I and II). Recent data in patients with heart failure with preserved ejection fraction are encouraging. MRA could also have anti-arrhythmic effects on atrial and ventricular arrhythmias and may be helpful in patient ischemic heart disease through prevention of myocardial fibrosis and vascular damage. This article aims to discuss the pathophysiological effects of aldosterone in patients with cardiovascular disease and to review the current data that support the use of MRA in heart failure.

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.

Kcne3 deletion initiates extracardiac arrhythmogenesis in mice

Mutations in the human KCNE3 potassium channel ancillary subunit gene are associated with life-threatening ventricular arrhythmias. Most genes underlying inherited cardiac arrhythmias, including KCNE3, are not exclusively expressed in the heart, suggesting potentially complex disease etiologies. Here we investigated mechanisms of KCNE3-linked arrhythmogenesis in Kcne3(-/-) mice using real-time qPCR, echo- and electrocardiography, ventricular myocyte patch-clamp, coronary artery ligation/reperfusion, blood analysis, cardiac synaptosome exocytosis, microarray and pathway analysis, and multitissue histology. Kcne3 transcript was undetectable in adult mouse atria, ventricles, and adrenal glands, but Kcne3(-/-) mice exhibited 2.3-fold elevated serum aldosterone (P=0.003) and differentially expressed gene networks consistent with an adrenal-targeted autoimmune response. Furthermore, 8/8 Kcne3(-/-) mice vs. 0/8 Kcne3(+/+) mice exhibited an activated-lymphocyte adrenal infiltration (P=0.0002). Kcne3 deletion also caused aldosterone-dependent ventricular repolarization delay (19.6% mean QTc prolongation in females; P<0.05) and aldosterone-dependent predisposition to postischemia arrhythmogenesis. Thus, 5/11 Kcne3(-/-) mice vs. 0/10 Kcne3(+/+) mice exhibited sustained ventricular tachycardia during reperfusion (P<0.05). Kcne3 deletion is therefore arrhythmogenic by a novel mechanism in which secondary hyperaldosteronism, associated with an adrenal-specific lymphocyte infiltration, impairs ventricular repolarization. The findings highlight the importance of considering extracardiac pathogenesis when investigating arrhythmogenic mechanisms, even in inherited, monogenic channelopathies.

Impact of aldosterone antagonists on the substrate for atrial fibrillation: aldosterone promotes oxidative stress and atrial structural/electrical remodeling

Atrial fibrillation (AF), the most common cardiac arrhythmia, is an electrocardiographic description of a condition with multiple and complex underlying mechanisms. Oxidative stress is an important driver of structural remodeling that creates a substrate for AF. Oxidant radicals may promote increase of atrial oxidative damage, electrical and structural remodeling, and atrial inflammation. AF and other cardiovascular morbidities activate angiotensin (Ang-II)-dependent and independent cascades. A key component of the renin-angiotensin-aldosterone system (RAAS) is the mineralocorticoid aldosterone. Recent studies provide evidence of myocardial aldosterone synthesis. Aldosterone promotes cardiac oxidative stress, inflammation and structural/electrical remodeling via multiple mechanisms. In HF patients, aldosterone production is enhanced. In patients and in experimental HF and AF models, aldosterone receptor antagonists have favorable influences on cardiac remodeling and oxidative stress. Therapeutic approaches that seek to reduce AF burden by modulating the aldosterone system are likely beneficial but underutilized.

Effects of mineralocorticoid receptor antagonists on the risk of sudden cardiac death in patients with left ventricular systolic dysfunction: a meta-analysis of randomized controlled trials

BACKGROUND

Sudden cardiac death (SCD) is an important cause of death in patients with left ventricular systolic dysfunction. Mineralocorticoid receptor antagonists (MRAs) may attenuate this risk. The objective of this meta-analysis was to assess the impact of MRAs on SCD in patients with left ventricular systolic dysfunction.

METHODS AND RESULTS

We systematically searched PubMed, EMBASE, Cochrane, and other databases through March 30, 2012, without language restrictions. We included trials that enrolled patients with left ventricular ejection fraction of ≤45%, randomized subjects to MRAs versus control and reported outcomes on SCD, total and cardiovascular mortality. Eight published trials that enrolled 11 875 patients met inclusion criteria. Of these, 6 reported data on SCD and cardiovascular mortality, and 7 reported data on total mortality. No heterogeneity was observed among the trials. Patients treated with MRAs had 23% lower odds of experiencing SCD compared with controls (odds ratio, 0.77; 95% confidence interval, 0.66-0.89; P=0.001). Similar reductions were observed in cardiovascular (0.75; 95% confidence interval, 0.68-0.84; P<0.001) and total mortality (odds ratio, 0.74; 95% confidence interval, 0.63-0.86; P<0.001). Although publication bias was observed, the results did not change after a trim and fill test, suggesting that the impact of this bias was likely insignificant.

CONCLUSIONS

MRAs reduce the risk of SCD in patients with left ventricular systolic dysfunction. Comparative effectiveness studies of MRAs on SCD in usual care as well as studies evaluating the efficacy of other therapies to prevent SCD in patients receiving optimal MRA therapy are needed to guide clinical decision-making.

Impact of mineralocorticoid receptor antagonists on changes in cardiac structure and function of left ventricular dysfunction: a meta-analysis of randomized controlled trials

BACKGROUND

A comprehensive evaluation of the benefits of mineralocorticoid receptor antagonists on cardiac remodeling is lacking. We aimed to evaluate the impact of mineralocorticoid receptor antagonists on changes in cardiac structure and function of left ventricular dysfunction.

METHODS AND RESULTS

Articles were identified by online searches in PubMed, EMBASE, Cochrane, and ClinicalTrials.gov databases before June 2012, by hand searches of reviews and relevant journals, and by contact with the authors. Qualified articles were restricted to randomized controlled trials. There were, respectively, 12, 4, and 3 qualified trials that randomized 572, 647, and 407 patients to spironolactone, canrenoate, and eplerenone, and 531, 655, and 395 patients to placebo or active treatment, respectively. Overall, under mineralocorticoid receptor antagonist treatment there was improvement in left ventricular ejection fraction (weighted mean difference, 2.97; 95% confidence interval [95% CI], 2.26-3.67; P<0.0005), left ventricular end-systolic and end-diastolic volume index (weighted mean difference, -5.64; 95% CI, -7.94 to -3.34; P<0.0005 and weighted mean difference, -7.46; 95% CI, -11.63 to -3.3; P<0.0005), serum amino-terminal peptide of procollagen type-III (weighted mean difference, -1.12; 95% CI, -1.49 to -0.74; P<0.0005), B-type natriuretic peptide (weighted mean difference, -67.06; 95% CI, -91.24 to -42.88; P<0.0005), peak velocities of early mitral inflow (E; weighted mean difference, -9.57; 95% CI, -12.98 to -6.17; P<0.0005), and E wave deceleration time (weighted mean difference, 7.08; 95% CI, 4.07-10.09; P<0.0005). There was low probability of heterogeneity and publication bias.

CONCLUSIONS

Our findings demonstrate that mineralocorticoid receptor antagonist treatment may exert beneficial effects on the reversal of cardiac remodeling and improvement of left ventricular function.

When conventional heart failure therapy is not enough: angiotensin receptor blocker, direct renin inhibitor, or aldosterone antagonist?

In patients on conventional heart failure therapy including angiotensin-converting enzyme (ACE) inhibitors, the addition of angiotensin receptor blockers (ARBs), direct renin inhibitors (DRIs), or aldosterone antagonists are therapeutic options to further reduce the risk of cardiovascular events. However, whether one is preferable over the other is not known. PubMed, EMBASE, and Cochrane Central Register of Controlled Trials databases were searched for randomized clinical trials (RCTs), until March 2011, of trials testing either an ARB, DRI, or an aldosterone antagonist in patients with heart failure who were on conventional heart failure therapy with follow-up of at least 3 months. Efficacy (death, cardiovascular death, nonfatal myocardial infarction, heart failure hospitalization and composite of cardiovascular death or heart failure hospitalization) and safety (hyperkalemia, hypotension, renal failure) outcomes were compared. The authors identified 16 RCTs involving 31,429 participants that satisfied the inclusion criteria. When compared with placebo (reference rate ratio [RR] of 1), aldosterone antagonists reduced the rate of death (RR, 0.79; 95% credibility interval [CrI], 0.66-0.98), cardiovascular death (RR, 0.78; 95% CrI, 0.65-0.93), heart failure hospitalization (RR, 0.74; 95% CrI, 0.55-0.94), and the composite of cardiovascular death or heart failure hospitalization (RR, 0.73; 95% CrI, 0.55-0.90) with no difference for other efficacy outcomes. However, ARBs and DRIs did not result in any significant reduction in the rate of any of the efficacy outcomes when compared with placebo. When compared with placebo (RR=1), ARBs increased the rate of hyperkalemia (138% increase), renal failure (126% increase), and hypotension (63% increase). Similarly, aldosterone antagonists resulted in a 110% increase in hyperkalemia and DRIs with a 98% increase in hypotension. In patients with heart failure and reduced systolic function on conventional heart failure medications, the risk benefit ratio favors the addition of aldosterone antagonists over ARBs or DRIs.

Eplerenone is not superior to older and less expensive aldosterone antagonists

INTRODUCTION

Eplerenone is publicized to be extremely effective in reducing mortality from heart failure, with a reasonable side-effect profile. However, it is much more expensive compared with older aldosterone antagonists. We reviewed available evidence to assess whether increased expense was justified with outcomes data.

METHODS AND RESULTS

The authors searched the PubMed, CENTRAL, CINAHL, and EMBASE databases for randomized controlled trials from 1966 through July 2011. Interventions included aldosterone antagonists (Aldactone [Pfizer, NY, NY], canrenone, eplerenone) in systolic heart failure. The comparator included standard medical therapy or placebo, or both. Outcomes assessed were mortality in the intervention versus the comparator groups, and rates of adverse events at the end of at least 8 weeks of follow-up. Event rates were compared using a forest plot of relative risk (RR) (95% confidence interval [CI]) using a random-effects model (Mantel-Haenszel) between the aldosterone antagonists and controls. We included 13 studies for aldosterone antagonists other than eplerenone, and 3 studies for eplerenone. There was significant reduction of mortality with all aldosterone antagonists, but eplerenone (15% mortality relative reduction; RR 0.85; 95% CI, 0.77-0.93; P=.0007) was outperformed by other aldosterone antagonists, namely, spironolactone and canrenone (26% mortality relative reduction; RR 0.74; 95% CI, 0.66-0.83; P <.0001). Reduction in cardiovascular mortality with eplerenone was 17% (RR 0.83; 95% CI, 0.75-0.92; P=.0005), while that with other aldosterone antagonists was 25% (RR 0.75; 95% CI, 0.67-0.84, P <.0001), without contributing significantly to an improved side-effect profile.

CONCLUSION

Eplerenone does not appear to be more effective in reducing clinical events compared with older, less expensive aldosterone antagonists.

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.

Cost-effectiveness of aldosterone antagonists for the treatment of post-myocardial infarction heart failure

OBJECTIVE

To assess the cost-effectiveness of eplerenone versus spironolactone as an adjunctive therapy to standard care in patients with heart failure (HF) following a myocardial infarction (post-MI) from the perspective of the National Health Service in the United Kingdom.

METHODS

A systematic review was conducted, and a Bayesian meta-regression approach was used to establish the relative effectiveness of eplerenone and spironolactone by using evidence from randomized controlled trials. A decision analytic model was developed to assess the costs and consequences associated with the primary outcome of the trials over a lifetime time horizon.

RESULTS

The incremental cost-effectiveness ratio of eplerenone compared with that of standard care alone was £ 4457 and £ 7893 for each additional quality-adjusted life-year when 2-year and lifetime treatment duration was assumed, respectively. In both scenarios, spironolactone did not appear cost-effective compared with eplerenone. The results were sensitive to the higher relative effectiveness estimated for eplerenone compared with spironolactone from the meta-regression. When a class effect was assumed for the effect on mortality and hospitalizations, spironolactone emerged as the most cost-effective treatment.

CONCLUSIONS

Eplerenone appears more cost-effective than spironolactone for the treatment of post-MI HF. These findings, however, remain subject to important uncertainties regarding the effects of treatment on major clinical events. An adequately powered, well-conducted randomized controlled trial that directly compares spironolactone and eplerenone may be required to provide more robust evidence on the optimal management of post-MI HF. Despite these uncertainties, the use of an aldosterone antagonist was consistently demonstrated to be a highly cost-effective strategy for the management of post-MI HF in the National Health Service.

Thrombotic microangiopathy: a role for magnesium?

Despite advances in more recent years, the pathophysiology and especially treatment modalities of thrombotic microangiopathy (TMA) largely remain enigmatic. Disruption of endothelial homeostasis plays an essential role in TMA. Considering the proven causal association between magnesium and both endothelial function and platelet aggregability, we speculate that a magnesium deficit could influence the course of TMA and the related haemolytic uraemic syndrome and thrombotic thrombocytopenic purpura. A predisposition towards TMA is seen in many conditions with both extracellular and intracellular magnesium deficiency. We propose a rationale for magnesium supplementation in TMA, in analogy with its evidence-based therapeutic application in pre-eclampsia and suggest, based on theoretical grounds, that it might attenuate the development of TMA, minimise its severity and prevent its recurrence. This is based on several lines of evidence from both in vitro and in vivo data showing dose-dependent effects of magnesium supplementation on nitric oxide production, platelet aggregability and inflammation. Our hypothesis, which is further amenable to assessment in animal models before therapeutic applications in humans are implemented, could be explored both in vitro and in vivo to decipher the potential role of magnesium deficit in TMA and of the effects of its supplementation.

The meaning of hypokalemia in heart failure

Maintenance of normal potassium (K(+)) homeostasis has become an increasingly important limiting factor in the therapy of heart failure (HF). With the application of loop diuretics and digoxin, hypokalemia has become a frequent and feared side effect of treatment. Low serum K(+) in HF may be also a marker of increased neurohormonal activity and disease progression. To gain the maximum benefit from treatment, we need to individualize drug use and carefully monitor electrolytes. Symptomatic HF patients (New York Heart Association class III-IV) should be prescribed the lowest dose of diuretic necessary to maintain euvolemia. Mild hypokalemia may be corrected by the use of aldosterone receptor antagonists such as spironolactone or eplerenone. However, a more severe hypokalemia should preferably be corrected using K(+) supplement. Serum K levels should be frequently checked and maintained between 4.0 and 5.5 mEq/l (mmol/l).

What is the risk of hyperkalaemia in heart failure?

INTRODUCTION

Chronic heart failure (CHF) is the only major cardiovascular disease whose prevalence and incidence are thought to be increasing. Potassium balance may be lost both through the neurohormonal mechanisms involved in cardiovascular diseases and through the drugs used in their treatment. Avoiding both hypo- and hyperkalemia is difficult but beneficial in CHF.

AREAS COVERED

Aldosterone production is decreased in the elderly, diabetic patients, and those receiving drugs that block the production or action of renin and angiotensin II. As a result, these groups, as well as those with already impaired potassium excretion due to progressive age or disease-related decline in glomerular filtration rate, are particularly vulnerable to the development of hyperkalemia.

EXPERT OPINION

Evidence from several studies suggests that, in patients with CHF, serum potassium should be maintained between 4.0 and 5.5 mEq/L. To gain the maximum benefit from aldosterone antagonists it is necessary to individualize their use; it is also necessary to carefully monitor electrolytes.