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

Prediction of endogenous mineralocorticoid receptor activity by depressor effects of mineralocorticoid receptor antagonists in patients with primary aldosteronism

Patients with primary aldosteronism have an increased risk of developing cardiovascular disease. The response to mineralocorticoid receptor antagonists varies among individuals, indicating diverse mineralocorticoid receptor activities in these patients. This study explored the factors linked to the efficacy of blood pressure reduction through mineralocorticoid receptor antagonists in patients with primary aldosteronism. We examined the relationship between the reduction in blood pressure and patient characteristics in a group of 41 patients with primary aldosteronism (24 males, mean age 55 ± 13 years, including 34 patients diagnosed with bilateral primary aldosteronism) before and after undergoing treatment with mineralocorticoid receptor antagonists. Significant reductions in office blood pressure were observed 3 and 6 months after treatment initiation. Single correlation analyses showed that the urinary chloride-to-potassium ratio displayed the strongest positive association with blood pressure reduction, surpassing plasma aldosterone concentration, plasma renin activity, and urinary sodium-to-potassium ratio, at 3 and 6 months. Multiple correlation analyses revealed a consistent and independent positive correlation between the urinary chloride-to-potassium ratio and blood pressure reduction at 3 and 6 months. The optimal threshold for the urinary chloride-to-potassium ratio with respect to its ability to lower blood pressure, was determined as 3.18. These results imply that the urinary chloride-to-potassium ratio may be independently associated with the effectiveness of blood pressure reduction facilitated by mineralocorticoid receptor antagonists. Moreover, it could potentially serve as a valuable predictor of the effectiveness of these agents and function as an indicator of endogenous mineralocorticoid receptor activity in patients with primary aldosteronism.

The effect of dapagliflozin therapy on ventricular repolarization parameters in electrocardiography in patients with diabetic cardiovascular disease

BACKGROUND

Dapagliflozin is an agent that has both antihyperglycemic effects and is significantly associated with a lower risk of cardiovascular events in patients with diabetes mellitus (DM). However, there is insufficient data and information about the effect of dapagliflozin on electrocardiographic (ECG) parameters.

AIM

The effects of dapagliflozin on ventricular repolarization parameters have not been fully elucidated yet. This study aimed to investigate whether dapagliflozin has a positive effect on ventricular repolarization heterogeneity parameters in patients with type 2 DM.

METHOD

We retrospectively enrolled 140 patients with a known diagnosis of type 2 DM who were newly prescribed dapagliflozin in addition to standard anti-diabetic therapy. The patients were divided into two groups according to whether they had cardiovascular disease (CVD). The effect of dapagliflozin treatment on ventricular repolarization parameters (frontal plane QRST angle, Tp-e interval, Tp-e/QTc, QTc, and QTc dispersion) was investigated, patient groups were compared before and after treatment.

RESULTS

Among 140 patients, 70 (50 %) had CVD and 70 (50 %) did not have CVD. Dapagliflozin treatment resulted in significant reductions in ventricular repolarization parameters over the study period in the CVD group with diabetes. Mean fQRST angle, Tp-e interval, Tp-e/QTc, QTc, and QTc dispersion were significantly lower than baseline values at 6-month follow-up visits in the CVD group (61.61 ± 9.22° vs 52.55 ± 8.31°, 74.45 ± 16.06 msec vs 63.27 ± 13.99 msec, 0.19 ± 0.03 vs 0.16 ± 0.03, 384.12 ± 47.93 msec vs 356.15 ± 43.31 mesc, 55.28 ± 5.50 msec vs 48.08 ± 6.48 msec for all pairwise comparisons p < 0.001).

CONCLUSION

Similar antihyperglycemic effects were found with dapagliflozin treatment in patients with and without CVD. However, significant reductions in ventricular repolarization parameters were observed only in patients with CVD.

Finerenone and effects on mortality in chronic kidney disease and type 2 diabetes: a FIDELITY analysis

AIMS

Finerenone reduces the risk of cardiovascular events in patients with chronic kidney disease (CKD) and type 2 diabetes (T2D). We investigated the causes of mortality in the FIDELITY population.

METHODS AND RESULTS

The FIDELITY prespecified pooled data analysis from FIDELIO-DKD and FIGARO-DKD excluded patients with heart failure and reduced ejection fraction. Outcomes included intention-to-treat and prespecified on-treatment analyses of the risk of all-cause and cardiovascular mortality. Of 13 026 patients [mean age, 64.8 years; mean estimated glomerular filtration rate (eGFR), 57.6 mL/min/1.73 m2], 99.8% were on renin-angiotensin system inhibitors. Finerenone reduced the incidence of all-cause and cardiovascular mortality vs. placebo (8.5% vs. 9.4% and 4.9% vs. 5.6%, respectively) and demonstrated significant on-treatment reductions [hazard ratio (HR), 0.82; 95% confidence interval (CI), 0.70-0.96; P = 0.014 and HR, 0.82; 95% CI, 0.67-0.99; P = 0.040, respectively]. Cardiovascular-related mortality was most common, and finerenone lowered the incidence of sudden cardiac death vs. placebo [1.3% (incidence rate 0.44/100 patient-years) vs. 1.8% (0.58/100 patient-years), respectively; HR, 0.75; 95% CI, 0.57-0.996; P = 0.046]. The effects of finerenone on mortality were similar across all Kidney Disease: Improving Global Outcomes risk groups. Event probability with finerenone at 4 years was consistent irrespective of baseline urine albumin-to-creatinine ratio, but seemingly more pronounced in patients with higher baseline eGFR.

CONCLUSION

In FIDELITY, finerenone significantly reduced the risk of all-cause and cardiovascular mortality vs. placebo in patients with T2D across a broad spectrum of CKD stages while on treatment, as well as sudden cardiac death in the intention-to-treat population.

CLINICAL TRIALS REGISTRATION

FIDELIO-DKD and FIGARO-DKD are registered with ClinicalTrials.gov, numbers NCT02540993 and NCT02545049, respectively (funded by Bayer AG).

Roles of Mineralocorticoid Receptors in Cardiovascular and Cardiorenal Diseases

Mineralocorticoid receptor (MR) activation in the heart and vessels leads to pathological effects, such as excessive extracellular matrix accumulation, oxidative stress, and sustained inflammation. In these organs, the MR is expressed in cardiomyocytes, fibroblasts, endothelial cells, smooth muscle cells, and inflammatory cells. We review the accumulating experimental and clinical evidence that pharmacological MR antagonism has a positive impact on a battery of cardiac and vascular pathological states, including heart failure, myocardial infarction, arrhythmic diseases, atherosclerosis, vascular stiffness, and cardiac and vascular injury linked to metabolic comorbidities and chronic kidney disease. Moreover, we present perspectives on optimization of the use of MR antagonists in patients more likely to respond to such therapy and review the evidence suggesting that novel nonsteroidal MR antagonists offer an improved safety profile while retaining their cardiovascular protective effects. Finally, we highlight future therapeutic applications of MR antagonists in cardiovascular injury.

Effect of sacubitril/valsartan on investigator-reported ventricular arrhythmias in PARADIGM-HF

Aims

Sudden death is a leading cause of mortality in heart failure with reduced ejection fraction (HFrEF). In PARADIGM‐HF, sacubitril/valsartan reduced the incidence of sudden death. The purpose of this post hoc study was to analyse the effect of sacubitril/valsartan, compared to enalapril, on the incidence of ventricular arrhythmias.

Methods and results

Adverse event reports related to ventricular arrhythmias were examined in PARADIGM‐HF. The effect of randomized treatment on two arrhythmia outcomes was analysed: ventricular arrhythmias and the composite of a ventricular arrhythmia, implantable cardioverter defibrillator (ICD) shock or resuscitated cardiac arrest. The risk of death related to a ventricular arrhythmia was examined in time‐updated models. The interaction between heart failure aetiology, or baseline ICD/cardiac resynchronization therapy‐defibrillator (CRT‐D) use, and the effect of sacubitril/valsartan was analysed. Of the 8399 participants, 333 (4.0%) reported a ventricular arrhythmia and 372 (4.4%) the composite arrhythmia outcome. Ventricular arrhythmias were associated with higher mortality. Compared with enalapril, sacubitril/valsartan reduced the risk of a ventricular arrhythmia (hazard ratio [HR] 0.76, 95% confidence interval [CI] 0.62–0.95; p = 0.015) and the composite arrhythmia outcome (HR 0.79, 95% CI 0.65–0.97; p = 0.025). The treatment effect was maintained after adjustment and accounting for the competing risk of death. Baseline ICD/CRT‐D use did not modify the effect of sacubitril/valsartan, but aetiology did: HR in patients with an ischaemic aetiology 0.93 (95% CI 0.71–1.21) versus 0.53 (95% CI 0.37–0.78) in those without an ischaemic aetiology (p for interaction = 0.020).

Conclusions

Sacubitril/valsartan reduced the incidence of investigator‐reported ventricular arrhythmias in patients with HFrEF. This effect may have been greater in patients with a non‐ischaemic aetiology.

Effect of dapagliflozin on ventricular arrhythmias, resuscitated cardiac arrest, or sudden death in DAPA-HF

AIMS

The aim of this study was to examine the effect of dapagliflozin on the incidence of ventricular arrhythmias and sudden death in patients with heart failure and reduced ejection fraction (HFrEF).

METHODS AND RESULTS

In a post hoc analysis of DAPA-HF, we examined serious adverse event reports related to ventricular arrhythmias or cardiac arrest, in addition to adjudicated sudden death. The effect of dapagliflozin, compared with placebo, on the composite of the first occurrence of any serious ventricular arrhythmia, resuscitated cardiac arrest, or sudden death was examined using Cox proportional hazards models. A serious ventricular arrhythmia was reported in 115 (2.4%) of the 4744 patients in DAPA-HF (ventricular fibrillation in 15 patients, ventricular tachycardia in 86, 'other' ventricular arrhythmia/tachyarrhythmia in 12, and torsade de pointes in 2 patients). A total of 206 (41%) of the 500 cardiovascular deaths occurred suddenly. Eight patients survived resuscitation from cardiac arrest. Independent predictors of the composite outcome (first occurrence of any serious ventricular arrhythmia, resuscitated cardiac arrest or sudden death), ranked by chi-square value, were log-transformed N-terminal pro-B-type natriuretic peptide, history of ventricular arrhythmia, left ventricular ejection fraction, systolic blood pressure, history of myocardial infarction, male sex, body mass index, serum sodium concentration, non-white race, treatment with dapagliflozin, and cardiac resynchronization therapy. Of participants assigned to dapagliflozin, 140/2373 patients (5.9%) experienced the composite outcome compared with 175/2371 patients (7.4%) in the placebo group [hazard ratio 0.79 (95% confidence interval 0.63-0.99), P = 0.037], and the effect was consistent across each of the components of the composite outcome.

CONCLUSIONS

Dapagliflozin reduced the risk of any serious ventricular arrhythmia, cardiac arrest, or sudden death when added to conventional therapy in patients with HFrEF.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov unique identifier: NCT03036124 (DAPA-HF).

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.

Management of primary aldosteronism and mineralocorticoid receptor-associated hypertension

Resistant hypertension is associated with a poor prognosis due to organ damage caused by prolonged suboptimal blood pressure control. The concomitant use of mineralocorticoid receptor (MR) antagonists with other antihypertensives has been shown to improve blood pressure control in some patients with resistant hypertension, and such patients are considered to have MR-associated hypertension. MR-associated hypertension is classified into two subtypes: one with a high plasma aldosterone level, which includes primary aldosteronism (PA), and the other with a normal aldosterone level. In patients with unilateral PA, adrenalectomy may be the first-choice procedure, while in patients with bilateral PA, MR antagonists are selected. In addition, in patients with other types of MR-associated hypertension with high aldosterone levels, MR antagonists may be selected as a first-line therapy. In patients with normal aldosterone levels, ARBs or ACE inhibitors are used as a first-line therapy, and MR antagonists may be used as an add-on agent. Since MR antagonist therapy may have efficacy as a first-line or add-on agent in these patients, it is important to recognize this type of hypertension. Further studies are needed to elucidate the pathogenesis and management of MR-associated hypertension in more detail to improve the clinical outcomes of patients with MR-associated hypertension.

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.

Antiarrhythmic Effect of Sacubitril-Valsartan: Cause or Consequence of Clinical Improvement?

Sacubitril/Valsartan (LCZ696) reduced sudden cardiac death in the PARADIGM-HF trial. However, the mechanism by which LCZ696 reduces ventricular arrhythmias remains unclear. The aim of this study was to compare electrocardiographic (ECG) parameters and mechanical dispersion index, assessed by left ventricular (LV) global longitudinal strain (GLS), before and after LCZ696 therapy. We prospectively evaluated chronic Heart Failure (HF) patients with LV ejection fraction ≤40%, despite optimal medical and device therapy, in which LCZ696 therapy was started, while no additional HF treatment was expected to change. ECG and transthoracic echocardiographic data were gathered in the week before starting LCZ696 and at six months of therapy. A semiautomated analysis of LV GLS was performed and mechanical dispersion index was defined as the standard deviation from 16 time intervals corresponding to each LV segment. Of the 42 patients, 35 completed the six month follow-up, since two patients died and five discontinued treatment for adverse events. QTc interval (451.9 vs. 426.0 ms, p < 0.001), QRS duration (125.1 vs. 120.8 ms, p = 0.033) and mechanical dispersion index (88.4 vs. 78.1 ms, p = 0.036) were significantly reduced at six months. LCZ696 therapy is associated with a reduction in QTc interval, QRS duration and mechanical dispersion index as assessed by LV GLS.

The Role of Mineralocorticoid Receptor Antagonists in Heart Failure with Reduced Ejection Fraction

Background:

Heart failure (HF) is a worldwide modern epidemic, associated with significant morbidity and mortality. Several causes have been identified for the syndrome, most of which share common pathophysiologic pathways, including neurohormonal activation. Central to the latter lies activation of the reninangiotensin- aldosterone system, and its effects on cardiovascular disease progression.

Objectives:

The aim of this review is to summarize the pathophysiology of aldosterone and the effects of its blockage in the failing heart, as well as to provide state-of-the-art evidence, and address future perspectives regarding the use of mineralocorticoid receptor antagonists in heart failure with reduced ejection fraction.

Method:

Literature was reviewed for studies that assess the pathophysiology of aldosterone in HF with reduced ejection fraction (HFrEF), and the effects of mineralocorticoid receptor antagonists (MRAs) in this condition.

Results:

Several major society guidelines have synthesized the available evidence on HFrEF management, and drugs that block the renin-angiotensin-aldosterone system at different levels continue to form the key component of standard of care for these patients. Mineralocorticoid receptor antagonists are an important part of HFrEF pharmacologic treatment, and their use is supported by a high level of evidence studies. This class of drugs demonstrated significant benefits for morbidity and mortality, across the spectrum oh HFrEF, including patients after acute myocardial infarction.

Conclusion:

Current evidence supports the central role of aldosterone in HFrEF progression, and the significant benefits on outcomes with the use of MRAs.

Mineralocorticoid Receptor and Cardiovascular Disease

Activation of the mineralocorticoid receptor (MR) in the distal nephron by its ligand, aldosterone, plays an important role in sodium reabsorption and blood pressure regulation. However, expression of the MR goes beyond the kidney. It is expressed in a variety of other tissues in which its activation could lead to tissue injury. Indeed, MR activation in the cardiovascular (CV) system has been shown to promote hypertension, fibrosis, and inflammation. Pharmacological blockade of the MR has protective effects in several animal models of CV disease. Furthermore, the use of MR antagonists is beneficial for heart failure patients, preventing mortality and morbidity. A better understanding of the implications of the MR in the setting of CV diseases is critical for refining treatments and improving patient care. The mechanisms involved in the deleterious effects of MR activation are complex and include oxidative stress, inflammation, and fibrosis. This review will discuss the pathological role of the MR in the CV system and the major mechanisms underlying it.

Effectiveness of drug interventions to prevent sudden cardiac death in patients with heart failure and reduced ejection fraction: an overview of systematic reviews

OBJECTIVES

To summarise and synthesise the current evidence regarding the effectiveness of drug interventions to prevent sudden cardiac death (SCD) and all-cause mortality in patients with heart failure with reduced ejection fraction (HFrEF).

DESIGN

Overview of systematic reviews.

DATA SOURCES

MEDLINE, Embase, ISI Web of Science and Cochrane Library from inception to May 2017; manual search of references of included studies for potentially relevant reviews.

ELIGIBILITY CRITERIA FOR STUDY SELECTION

We reviewed the effectiveness of drug interventions for SCD and all-cause mortality prevention in patients with HFrEF. We included overviews, systematic reviews and meta-analyses of randomised controlled trials of beta-blockers, angiotensin-converting enzyme inhibitors (ACE-i), angiotensin receptor blockers (ARBs), antialdosterones or mineralocorticoid-receptor antagonists, amiodarone, other antiarrhythmic drugs, combined ARB/neprilysin inhibitors, statins and fish oil supplementation.

REVIEW METHODS

Two independent reviewers extracted data and assessed the methodological quality of the reviews and the quality of evidence for the primary studies for each drug intervention, using Assessing the Methodological Quality of Systematic Reviews (AMSTAR) and Grading of Recommendations, Assessment, Development and Evaluation(GRADE), respectively.

RESULTS

We identified 41 reviews. Beta-blockers, antialdosterones and combined ARB/neprilysin inhibitors appeared effective to prevent SCD and all-cause mortality. ACE-i significantly reduced all-cause mortality but not SCD events. ARBs and statins were ineffective where antiarrhythmic drugs and omega-3 fatty acids had unclear evidence of effectiveness for prevention of SCD and all-cause mortality.

CONCLUSIONS

This comprehensive overview of systematic reviews confirms that beta-blockers, antialdosterone agents and combined ARB/neprilysin inhibitors are effective on SCD prevention but not ACE-i or ARBs. In patients with high risk of SCD, an alternative therapeutic strategy should be explored in future research.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO 2017: CRD42017067442.

Spironolactone Attenuates Doxorubicin-induced Cardiotoxicity in Rats

INTRODUCTION

In this study, we examined whether spironolactone (SP) could inhibit doxorubicin (DOX)-induced cardiotoxicity in the rat heart.

METHODS

Rats were randomized into four groups (n = 6): (1) the control group; (2) the SP group; (3) the DOX group; and (4) the SP + DOX group. The rats were evaluated for electrocardiography and cardiac function. The cardiac collagen, cardiomyocyte apoptosis, and the remodeling-related proteins were determined.

RESULTS

Rats treated with DOX showed prolongation of QTc and decreased left ventricular ejection fraction (EF) and fractional shortening (FS) (P < 0.05) showed left ventricular end-diastolic dimensions (LVEDD) and left ventricular end-systolic dimensions (LVESD) were significantly increased (P < 0.05). SP prevented these pathophysiological alterations (P < 0.05). In DOX-treated group, cardiac fibrosis, apoptotic cell number, and cardiac collagen volume fraction were higher than control group (P < 0.05); these effects were prevented by cotreatment of SP (P < 0.05). Moreover, the expressions of TGF-β1 and phosphorylated-Smad3 were increased after DOX treatment (P < 0.05) and significantly reduced by coadministration of SP (P < 0.05).

CONCLUSIONS

This study show that SP may have a protective effect on DOX-induced cardiotoxicity.

Emerging Roles of the Mineralocorticoid Receptor in Pathology: Toward New Paradigms in Clinical Pharmacology

The mineralocorticoid receptor (MR) and its ligand aldosterone are the principal modulators of hormone-regulated renal sodium reabsorption. In addition to the kidney, there are several other cells and organs expressing MR, in which its activation mediates pathologic changes, indicating potential therapeutic applications of pharmacological MR antagonism. Steroidal MR antagonists have been used for decades to fight hypertension and more recently heart failure. New therapeutic indications are now arising, and nonsteroidal MR antagonists are currently under development. This review is focused on nonclassic MR targets in cardiac, vascular, renal, metabolic, ocular, and cutaneous diseases. The MR, associated with other risk factors, is involved in organ fibrosis, inflammation, oxidative stress, and aging; for example, in the kidney and heart MR mediates hormonal tissue-specific ion channel regulation. Genetic and epigenetic modifications of MR expression/activity that have been documented in hypertension may also present significant risk factors in other diseases and be susceptible to MR antagonism. Excess mineralocorticoid signaling, mediated by aldosterone or glucocorticoids binding, now appears deleterious in the progression of pathologies that may lead to end-stage organ failure and could therefore benefit from the repositioning of pharmacological MR antagonists.

Aldosterone-to-Renin Ratio Is Associated With Reduced 24-Hour Heart Rate Variability and QTc Prolongation in Hypertensive Patients

Aldosterone is considered to exert direct effects on the myocardium and the sympathetic nervous system. Both QT time and heart rate (HR) variability (HRV) are considered to be markers of arrhythmic risk and autonomous dysregulation. In this study, we investigated the associations between aldosterone, QT time, and HRV in patients with arterial hypertension.We recruited 477 hypertensive patients (age: 60.2 ± 10.2 years; 52.3% females) with a mean systolic/diastolic 24-hour ambulatory blood pressure monitoring (ABPM) value of 128 ± 12.8/77.1 ± 9.2 mmHg and with a median of 2 (IQR: 1-3) antihypertensive agents. Patients were recruited from the outpatient clinic at the Department of Internal Medicine of the Medical University of Graz, Austria. Blood samples, 24-hour HRV derived from 24-hour blood pressure monitoring (ABPM) and ECG's were obtained. Plasma aldosterone and plasma renin concentrations were measured by means of a radioimmunoassay. Twenty-four-hour urine specimens were collected in parallel with ABPM.Mean QTc was 423.3 ± 42.0 milliseconds for males and 434.7 ± 38.3 milliseconds for females. Mean 24H-HR and 24H-HRV was 71.9 ± 9.8 and 10.0 ± 3.6 bpm, respectively. In linear regression analyses adjusted for age, sex, body mass index, ABPM, and current medication, aldosterone to active renin ratio (AARR) was significantly associated with the QTc interval, a marker for cardiac repolarization abnormalities (mean = 426 ± 42.4 milliseconds; β-coefficient = 0.121; P = 0.03) as well as with the 24-hour heart rate variability a surrogate for autonomic dysfunction (median = 9.67 [IQR = 7.38-12.22 bpm]; β-coefficient = -0.133; P = 0.01).In hypertensive patients, AARR is significantly related to QTc prolongation as well as HRV. Further studies investigating the effects of mineralocorticoid receptor blocker and aldosterone synthase inhibitors on QTc and HRV are warranted.

[Mineralocorticoid receptor antagonists in the treatment of patients with chronic heart failure. Positions in 2015]

Mineralocorticoid receptor antagonists (MCRA) are part of standard medical therapy for heart failure (HF). The clinical efficacy of MCRA in patients with systolic HF has been proven by randomized clinical trials. The efficacy of this drug group in patients with chronic HF with preserved left ventricular systolic function and the advent and practical introductions of safer new-generation MCRA remain to be answered.

Emerging cardiovascular indications of mineralocorticoid receptor antagonists

Mineralocorticoid receptor (MR) antagonism is a well-established treatment modality for patients with hypertension, heart failure, and left ventricular systolic dysfunction (LVSD) post-myocardial infarction (MI). There are emerging data showing potential benefits of MR antagonists in other cardiovascular conditions. Studies have shown association between MR activation and the development of myocardial fibrosis, coronary artery disease, metabolic syndrome, and cerebrovascular diseases. This review examines the preclinical and clinical data of MR antagonists for novel indications including heart failure with preserved ejection fraction (HFPEF), pulmonary arterial hypertension (PAH), arrhythmia, sudden cardiac death, valvular heart disease, metabolic syndrome, renal disease, and stroke. MR antagonists are not licensed for these conditions yet; however, emerging data suggest that indication for MR antagonists are likely to broaden; further studies are warranted.

Mineralocorticoids in the heart and vasculature: new insights for old hormones

The mineralocorticoid aldosterone is a key regulator of water and electrolyte homeostasis. Numerous recent developments have advanced the field of mineralocorticoid pharmacology—namely, clinical trials have shown the beneficial effects of aldosterone antagonists in chronic heart failure and post-myocardial infarction treatment. Experimental studies using cell type-specific gene targeting of the mineralocorticoid receptor (MR) gene in mice have revealed the importance of extrarenal aldosterone signaling in cardiac myocytes, endothelial cells, vascular smooth cells, and macrophages. In addition, several molecular pathways involving signal transduction via the classical MR as well as the G protein-coupled receptor GPER mediate the diverse spectrum of effects of aldosterone on cells. This knowledge has initiated the development of new pharmacological ligands to specifically interfere with targets on different levels of aldosterone signaling. For example, aldosterone synthase inhibitors such as LCI699 and the novel nonsteroidal MR antagonist BAY 94-8862 have been tested in clinical trials. Interference with the interaction between MR and its coregulators seems to be a promising strategy toward the development of selective MR modulators.

Early eplerenone treatment in patients with acute ST-elevation myocardial infarction without heart failure: the Randomized Double-Blind Reminder Study

AIMS

We aimed to assess the impact of eplerenone on cardiovascular (CV) outcomes in STEMI without known heart failure, when initiated within 24 h of symptom onset.

METHODS AND RESULTS

In this randomized, placebo-controlled, double-blind trial, we assigned 1012 patients with acute STEMI and without a history of heart failure to receive either eplerenone (25-50 mg once daily) or placebo in addition to standard therapy. The primary endpoint was the composite of CV mortality, re-hospitalization, or, extended initial hospital stay, due to diagnosis of HF, sustained ventricular tachycardia or fibrillation, ejection fraction ≤40%, or elevated BNP/NT-proBNP at 1 month or more after randomization. BNP elevation was defined as BNP levels or values above 200 pg/mL or NT-proBNP values above 450 pg/mL (in patients aged below 50); above 900 pg/mL (age 50-75 years) or above 1800 pg/mL (patients older than 75). After a mean follow-up of 10.5 months, the primary endpoint occurred in 92 patients (18.2%) in the eplerenone group and in 149 patients (29.4%) in the placebo group [adjusted hazard ratio (HR), 0.58; 95% confidence interval (CI), 0.45-0.76; P < 0.0001]. The primary endpoint was driven by a high BNP/NT-proBNP level (adjusted HR, 0.60; 95% CI, 0.45-0.79; P < 0.0003). Adverse event rates were similar in both groups. Serum potassium levels exceeded 5.5 mmol/L in 5.6 vs. 3.2% (P = 0.09) and were below 3.5 mmol/L in 1.4 vs. 5.6% of patients (P = 0.0002), in the eplerenone and placebo groups, respectively.

CONCLUSION

The addition of eplerenone during the acute phase of STEMI was safe and well tolerated. It reduced the primary endpoint over a mean 13 months follow-up mostly because of significantly lower BNP/NT-proBNP levels. Additional studies are needed to clarify the role of early use of MRAs in STEMI patients without heart failure.

CLINICAL TRIAL REGISTRATION

NCT01176968.

Diuretics: a review and update

Diuretics have been recommended as first-line treatment of hypertension and are also valuable in the management of hypervolemia and electrolyte disorders. This review summarizes the key features of the most commonly used diuretics. We then provide an update of clinical trials for diuretics during the past 5 years. Compared to other classes of medications, thiazide diuretics are at least as effective in reducing cardiovascular events (CVEs) in patients with hypertension and are more effective than β-blockers and angiotensin-converting enzyme inhibitors in reducing stroke. Observational cohort data and a network analysis have shown that CVEs are lowered by one-fifth from chlorthalidone when compared to the commonly used thiazide, hydrochlorothiazide. Relative to placebo, chlorthalidone increases life expectancy. In those aged 80 years and older, the diuretic, indapamide, lowers CVEs relative to placebo. The aldosterone antagonist, eplerenone, lowers total mortality in early congestive heart failure. The benefit of eplerenone following acute myocardial infarction (MI) is limited to administration within 3 to 6 days post-MI. Aldosterone antagonists have been shown to lower the incidence of sudden cardiac death and to reduce proteinuria. In the setting of heart failure, long acting loop diuretics azosemide and torasemide are more effective in improving heart failure outcomes than the far more commonly used short acting furosemide. Evening dosing of diuretics appears to lower CVEs relative to morning dosing. In conclusion, diuretics are a diverse class of drugs that remain extremely important in the management of hypertension and hypervolemic states.

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.

Mineralocorticoid receptors and the heart, multiple cell types and multiple mechanisms: a focus on the cardiomyocyte

MR (mineralocorticoid receptor) activation in the heart plays a central role in the development of cardiovascular disease, including heart failure. The MR is present in many cell types within the myocardium, including cardiomyocytes, macrophages and the coronary vasculature. The specific role of the MR in each of these cell types in the initiation and progression of cardiac pathophysiology is not fully understood. Cardiomyocyte MRs are increasingly recognized to play a role in regulating cardiac function, electrical conduction and fibrosis, through direct signal mediation and through paracrine MR-dependent activity. Although MR blockade in the heart is an attractive therapeutic option for the treatment of heart failure and other forms of heart disease, current antagonists are limited by side effects owing to MR inactivation in other tissues (including renal targets). This has led to increased efforts to develop therapeutics that are more selective for cardiac MRs and which may have reduced the occurrence of side effects in non-cardiac tissues. A major clinical consideration in the treatment of cardiovascular disease is of the differences between males and females in the incidence and outcomes of cardiac events. There is clinical evidence that female sensitivity to endogenous MRs is more pronounced, and experimentally that MR-targeted interventions may be more efficacious in females. Given that sex differences have been described in MR signalling in a range of experimental settings and that the MR and oestrogen receptor pathways share some common signalling intermediates, it is becoming increasingly apparent that the mechanisms of MRs need to be evaluated in a sex-selective manner. Further research targeted to identify sex differences in cardiomyocyte MR activation and signalling processes has the potential to provide the basis for the development of cardiac-specific MR therapies that may also be sex-specific.

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.

New paradigms in the prevention of sudden cardiac arrest and heart failure treatment

Congestive heart failure is a very real public health issue not only in the United States, but worldwide. Mortality in patients with congestive heart failure is typically either sudden cardiac death or pump failure. Paradoxically, patients with less severe heart failure are at higher relative risk of sudden cardiac death. Defining which patients are best treated with implantable defibrillators and resynchronization is the purpose of this review.

Aldosterone and aldosterone antagonists in cardiac disease: what is known, what is new

Experimental and clinical studies indicate that exposure to high aldosterone concentrations causes cardiac damage independent of the blood pressure level. In recent years, it has become clear that the effects of aldosterone on the heart are mediated by actions on a variety of cell types and intracellular mechanisms that contribute to regulation of specific tissue responses, leading to hypertrophy and fibrosis. Most cardiac effects of aldosterone are mediated by activation of mineralocorticoid receptors that are detected in cardiac myocytes and fibroblasts. Clinical evidence of the unfavorable cardiac effects of aldosterone has been established in landmark studies that have tested the benefits of aldosterone antagonists in patients with heart failure and decreased ejection fraction. However, evidence of benefits of aldosterone antagonists occurring independent of the renal effects of these agents is not limited to patients with systolic heart failure. In this article, we briefly summarize the current knowledge on the effects of aldosterone antagonists on cardiac protection and highlight the most recent findings that have been obtained in different cardiac conditions with use of these drugs.