What is the optimal serum potassium level in cardiovascular patients?

Lethal Arrhythmia Induced by Severe Hypokalemia with Primary Aldosteronism: A Case Report and Literature Review

A 26-year-old woman experienced sudden loss of consciousness with respiratory arrest while engaged in a heated conversation shortly after consuming a carbohydrate-rich meal; she was resuscitated immediately. Severe hypokalemia became evident and was deemed to have caused lethal arrhythmia. She was diagnosed with a left aldosterone-producing adenoma and achieved remission following partial adrenalectomy. Primary aldosteronism is frequently complicated by hypokalemia; however, hypokalemia-induced lethal arrhythmias are rare. Clinicians should recognize that primary aldosteronism can potentially cause sudden death in apparently healthy individuals; hence, an early diagnosis and proper treatment are critical.

Effects of Serum Potassium on Mortality in Patients With ST-Elevation Myocardial Infarction

INTRODUCTION

Disturbances in potassium levels can induce ventricular arrhythmias and heighten mortality in patients with ST-elevation myocardial infarction (STEMI). This study evaluates the influence of sK levels on seven-day mortality and incidence of ventricular arrhythmias in STEMI patients to further improve clinical guidelines and outcomes.

METHODS

This retrospective, propensity-matched study analyzed approximately 250,000 acute STEMI patients from 55 major academic medical centers/healthcare organizations (HCOs) in the US Collaborative Network of the TriNetX database. The sK levels recorded on the day of STEMI diagnosis were categorized into four cohorts: sK ≤ 3.4 (hypokalemia), 3.5 ≤ sK ≤ 4.5 (normal-control), 4.6 ≤ sK ≤ 5.0 (high-normal), and sK ≥ 5.1 (hyperkalemia). Patient cohorts were propensity-matched using linear and logistic regression for demographics. Outcomes of seven-day mortality, ventricular tachycardia (VT), and ventricular fibrillation (VF) were compared between these cohorts and the control group.

RESULTS

The analysis showed hypokalemia was linked to significantly higher seven-day mortality (7.2% vs. 4.3%; RR 1.69; p<0.001), and increased rates of VT and VF. Similarly, hyperkalemia was associated with elevated mortality (12.7% vs. 4.6%; RR 2.76; p<0.001), VT, and VF rates. High-normal sK levels showed increased mortality (7.4% vs. 4.7%; RR 1.58; p<0.001), but unchanged VT or VF rates compared to the normal sK group.

CONCLUSION

This comprehensive study highlights the correlation of sK levels with death in STEMI patients, revealing a nearly doubled risk of mortality with hypokalemia and almost triples with hyperkalemia. More notably, the mortality for STEMIs is higher for high-normal vs normal sK values. Additionally, hypokalemia and hyperkalemia were found to significantly elevate VT and VF risks.

Potassium levels and the risk of all-cause and cardiovascular mortality among patients with cardiovascular diseases: a meta-analysis of cohort studies

BACKGROUND

Abnormal blood potassium levels are associated with an increased risk of cardiometabolic diseases and mortality in the general population; however, evidence regarding the association between dyskalemia and mortality among patients with cardiovascular disease (CVD) remains inconclusive. This study aimed to evaluate the association of potassium levels with all-cause and cardiovascular mortality among patients with CVD.

METHODS

PubMed, Embase, Web of Science, and Cochrane Library databases were searched up to August 2023 to identify relevant cohort studies among patients with CVD, such as myocardial infarction, stroke, and heart failure. Abnormal potassium levels were considered as hypokalemia or hyperkalemia. The primary outcomes were all-cause mortality based on follow-up length (including in-hospital, short-term and long-term mortality) and cardiovascular mortality. The methodological quality of included studies was assessed by using the Newcastle-Ottawa Scale. The pooled relative risks (RRs) and 95% confidence intervals (CIs) were calculated using random-effects models. Restricted cubic splines were applied to explore the dose-response relationship.

RESULTS

Thirty-one cohort studies involving 227,645 participants with an average age of 68.3 years were included in the meta-analysis, all of which achieved moderate to high quality. Hyperkalemia was significantly associated with an approximately 3.0-fold increased risk of all-cause in-hospital mortality (RR:2.78,95CI%:1.92,4.03), 1.8-fold of all-cause short-term mortality (RR:1.80, 95CI%:1.44,2.27), 1.3-fold of all-cause long-term mortality (RR:1.33, 95CI%:1.19,1.48) and 1.2-fold of cardiovascular mortality (RR:1.19, 95CI%:1.04,1.36). Similar positive associations were also observed between hypokalemia and risk of all-cause mortality and cardiovascular mortality. The RRs of all-cause in-hospital, short-term, long-term mortality and cardiovascular mortality with hyperkalemia were attenuated to 2.21 (95CI%:1.60,3.06), 1.46(95CI%:1.25,1.71), 1.23 (95CI%:1.09,1.39) and 1.13 (95CI%:1.00,1.27) when treating hypokalemia together with normokalemia as the reference group. A U-shaped association was observed between potassium levels and mortality, with the lowest risk at around 4.2 mmol/L.

CONCLUSIONS

Both hypokalemia and hyperkalemia were positively associated with the risk of mortality in patients with CVD. Our results support the importance of potassium homeostasis for improving the CVD management.

REGISTRATION

PROSPERO, CRD42022324337.

Management of Arrhythmias in the Cardiovascular Intensive Care Unit

Arrhythmias in the cardiovascular intensive care unit (CVICU) can be difficult to manage because of the complex hemodynamic and respiratory states of critically ill patients. Treating physicians must be educated to prevent, diagnose, and treat a multitude of tachyarrhythmias and bradyarrhythmias. In this review article, the authors outline a pragmatic approach to patient assessment, arrhythmia diagnosis, and management of the most common arrhythmias seen in the CVICU.

Congestion in Heart Failure: From the Secret of a Mummy to Today's Novel Diagnostic and Therapeutic Approaches: A Comprehensive Review

This review paper presents a review of the evolution of this disease throughout the centuries, describes and summarizes the pathophysiologic mechanisms, briefly discusses the mechanism of action of diuretics, presents their role in decongesting heart failure in patients, and reveals the data behind ultrafiltration in the management of acutely or chronically decompensated heart failure (ADHF), focusing on all the available data and advancements in this field. Acutely decompensated heart failure (ADHF) presents a critical clinical condition characterized by worsening symptoms and signs of heart failure, necessitating prompt intervention to alleviate congestion and improve cardiac function. Diuretics have traditionally been the mainstay for managing fluid overload in ADHF. Mounting evidence suggests that due to numerous causes, such as coexisting renal failure or chronic use of loop diuretics, an increasing rate of diuretic resistance is noticed and needs to be addressed. There has been a series of trials that combined diuretics of different categories without the expected results. Emerging evidence suggests that ultrafiltration may offer an alternative or adjunctive approach.

Associations between serum electrolyte and short-term outcomes in patients with acute decompensated heart failure

INTRODUCTION

There is a dearth of comprehensive studies on the association between serum electrolyte and adverse short-term prognosis of Chinese patients with acute decompensated heart failure (ADHF).

PATIENTS AND METHODS

A total of 5166 patients with ADHF were divided into four serum electrolyte-related study populations (potassium (n = 5145), sodium (n = 5135), chloride (n = 4966), serum total calcium (STC) (n = 4143)) under corresponding exclusions. Different logistic regression models were utilized to gauge the association between these electrolytes or the number of electrolyte abnormalities and the risk of a composite of all-cause mortality or 30-day heart failure (HF) readmission.

RESULTS

In multivariable adjusted analysis, patients with potassium below 3.5 mmol/L (odds ratios (ORs) 1.45; 95% confidence interval (CI):1.07-1.95), 4.01-4.50 mmol/L (OR: 1.29, CI: 1.02-1.62), 4.51-5.00 mmol/L (OR: 1.43, CI: 1.08-1.90) and above 5.00 mmol/L (OR: 1.74, CI: 1.21-2.51) had an increased risk of outcome when compared with potassium at 3.50-4.00 mmol/L. Sodium levels were inversely related to the risk of a composite outcome (<130 mmol/L: OR: 2.73 (95% CI, 1.81-4.12); 130-134 mmol/L: OR, 1.97 (CI, 1.45-2.68); 135-140 mmol/L: OR, 1.45 (CI, 1.17-1.81); p for trend < 0.001) in comparison with sodium at 141-145 mmol/L. Chloride < 95 mmol/L corresponded to a higher risk of a composite outcome with an OR of 1.65 (95% CI, 1.16-2.37) in contrast to chloride levels at 101-105 mmol/L. In addition, the adjusted ORs (95% CI) for a composite outcome comparing the STC < 2.00 and 2.00-2.24 vs. 2.25-2.58 mmol/L were 0.98 (0.69-1.43) and 1.13 (0.89-1.44), respectively. Besides that, the number of electrolyte abnormalities was positively related to the risk of a composite outcome (N = 1, OR 1.40, 95% CI: 1.13-1.73; N = 2, OR 2.51, 95% CI: 1.85-3.42; N = 3, OR 2.47, 95% CI: 1.45-4.19; p for trend < 0.001) in comparison with N = 0.

CONCLUSIONS

A deviation of potassium levels from 3.50 to 4.00 mmol/L, lower sodium levels and hypochloremia were associated with poorer short-term prognosis of ADHF. Furthermore, the number of electrolyte abnormalities positively correlated with adverse short-term prognosis of patients with ADHF. Key MessagesADHF patients with baseline serum potassium at first half part of normal range (3.50-4.00 mmol/L) may herald the lowest risk of recent cardiovascular events.Serum sodium and chloride levels exhibit discrepancies in terms of risk of short-term adverse events of ADHF patients.The number of electrolyte abnormalities is a significant predictor of poor short-term prognosis in patients with ADHF.

CLINICAL TRIAL REGISTRATION URL

http://www.chictr.org.cn/showproj.aspx?proj=23139. Unique identifier: ChiCTR-POC-17014020.

Clinical outcomes of serum potassium in patients with percutaneous coronary intervention: insights from a large single-center registry

Background

Serum potassium homeostasis plays an important role in myocardial electrical stability, but the impact of altered serum potassium levels on the major adverse cardiovascular and cerebral events (MACCE) in patients with percutaneous coronary intervention (PCI) has not been evaluated.

Aim

To evaluate the association between serum potassium level and the risk of MACCE in PCI patients.

Materials and methods

This retrospective study involved 8,263 in-patients from a single-center registry who were successfully treated with PCI between January 2003 and December 2020. Clinical data were collected for 24 h after admission. Data were analyzed from June 2003 to December 2021. The primary outcome was MACCE, defined as a composite of all-cause death, myocardial infarction, revascularization, stroke, and heart failure-related hospitalization.

Results

The median [interquartile range (IQR)] follow-up for all patients was 4.0 (2.1, 5.8) years, and 1,632 patients (19.7%) were diagnosed with MACCE. High serum potassium levels were associated with a 20% increased risk of MACCE (hazard ratio [HR]: 1.20, 95% confidence interval [CI]: 1.05-1.38, P = 0.008) and 72% increased risk of all-cause death (HR: 1.72, 95% CI: 1.39-2.14, P < 0.001). Multivariate Cox analysis showed that the risk of MACCE was higher in patients at the highest quartile of serum potassium (Q4 vs. Q1: adjusted HR: 1.18, 95% CI: 1.02-1.35, P = 0.026). Moreover, a higher serum potassium level was always associated with a higher risk of all-cause death (Q4 vs. Q1: adjusted HR: 1.50, 95% CI: 1.17-1.91, P = 0.001). A U-shaped relationship between serum potassium levels, MACCE, and all-cause death was derived in patients undergoing PCI. Serum potassium levels, maintained within the range of 3.8-4.0 mmol/L before PCI, exhibited the lowest risk of associated MACCE and all-cause death.

Conclusion

Our results demonstrate that the serum potassium level could be associated with higher risks of MACCE and all-cause death in PCI patients. In particular, serum potassium levels maintained at 3.8-4.0 mmol/L before PCI could lower the risk of MACCE and all-cause death.

Development and Validation of Nomogram for the Prediction of Malignant Ventricular Arrhythmia Including Circulating Inflammatory Cells in Patients with Acute ST-Segment Elevation Myocardial Infarction

Background

Malignant ventricular arrhythmia (MVA) can seriously affect the hemodynamic changes of the body. In this study, we developed and validated a nomogram to predict the in-hospital MVA risk in patients with STEMI after emergency PCI.

Methods

The multivariable logistic regression analysis included variables with a P<0.05 in the univariate logistic regression analysis and investigated the independent predictors affecting in-hospital MVA after PCI in patients with STEMI in the training cohort. The construction of a nomogram model used independent predictors to predict the risk of in-hospital MVA, and C-index, Hosmer-Lemeshow (HL) test, calibration curves, decision curve analysis (DCA), and receiver operating characteristic (ROC) were used to validate the nomogram.

Results

Killip class [OR=5.034 (95% CI: 1.596-15.809), P=0.005], CK-MB [OR=1.002 (95% CI: 1.001-1.004), P=0.022], serum potassium [OR=0.618 (95% CI: 0.406-0.918), P=0.020], NLR [OR=1.073 (95% CI: 1.034-1.115), P<0.001], and monocyte [OR=1.974 (95% CI: 1.376-2.925), P<0.001] were the independent predictors of in-hospital MVA after PCI in patients with STEMI. A nomogram including the 5 independent predictors was developed to predict the risk of in-hospital MVA. The C-index, equivalent to the area under the ROC curve (AUC), was 0.803 (95% confidence interval [CI]: 0.738-0.868) in the training cohort, and 0.801 (95% CI:0.692-0.911) in the validation cohort, showing that the nomogram had a good discrimination. The HL test (χ²=8.439, P=0.392 in the training cohort; χ²=9.730, P=0.285 in the validation cohort) revealed a good calibration. The DCA suggested an obvious clinical net benefit.

Conclusion

Killip class, CK-MB, serum potassium, NLR, and monocyte were independent factors for in-hospital MVA after PCI in patients with STEMI. The nomogram model constructed based on the above factors to predict the risk of in-hospital MVA had satisfactory discrimination, calibration, and clinical effectiveness, and was an excellent tool for early prediction of the risk of in-hospital MVA after PCI in patients with STEMI.

Treatment-induced increase in total body potassium in patients at high risk of ventricular arrhythmias; a randomized POTCAST substudy

OBJECTIVE

Hypokalemia is associated with increased risk of arrhythmias and it is recommended to monitor plasma potassium (p-K) regularly in at-risk patients with cardiovascular diseases. It is poorly understood if administration of potassium supplements and mineralocorticoid receptor antagonists (MRA) aimed at increasing p-K also increases intracellular potassium.

METHODS

Adults aged≥18 years with an implantable cardioverter defibrillator (ICD) were randomized (1:1) to a control group or to an intervention that included guidance on potassium rich diets, potassium supplements, and MRA to increase p-K to target levels of 4.5-5.0 mmol/l for six months. Total-body-potassium (TBK) was measured by a Whole-Body-Counter along with p-K at baseline, after six weeks, and after six months.

RESULTS

Fourteen patients (mean age: 59 years (standard deviation 14), 79% men) were included. Mean p-K was 3.8 mmol/l (0.2), and mean TBK was 1.50 g/kg (0.20) at baseline. After six-weeks, p-K had increased by 0.47 mmol/l (95%CI:0.14;0.81), p = 0.008 in the intervention group compared to controls, whereas no significant difference was found in TBK (44 mg/kg (-20;108), p = 0.17). After six-months, no significant difference was found in p-K as compared to baseline (0.16 mmol/l (-0.18;0.51), p = 0.36), but a significant increase in TBK of 82 mg/kg (16;148), p = 0.017 was found in the intervention group compared to controls.

CONCLUSIONS

Increased potassium intake and MRAs increased TBK gradually and a significant increase was seen after six months. The differentially regulated p-K and TBK challenges current knowledge on potassium homeostasis and the time required before the full potential of p-K increasing treatment can be anticipated.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT03833089).

Medical Treatment in Heart Failure with Reduced Ejection Fraction: A Proposed Algorithm Based on the Patient's Electrolytes and Congestion Status

In heart failure (HF) with reduced ejection fraction (HFrEF), four classes of drugs (β-blockers, angiotensin-converting enzyme inhibitors/angiotensin receptor neprilysin inhibitors, mineralocorticoid receptor antagonists, and the most recent Sodium-Glucose Co-Transporters 2 Inhibitors) have demonstrated positive results in randomized controlled trials (RCTs). Nevertheless, the latest RCTs are not proper for comparison since they were carried out at various times with dissimilar background therapies and the patients enrolled did not have the same characteristics. The difficulty of extrapolating from these trials and proposing a common framework appropriate for all cases is thus obvious. Despite the fact that these four agents are now the fundamental pillars of HFrEF treatment, the built-up algorithm of initiation and titration is a matter of debate. Electrolyte disturbances are common in HFrEF patients and can be attributed to several factors, such as the use of diuretics, renal impairment, and neurohormonal activation. We have identified several HFrEF phenotypes according to their sodium (Na+) and potassium (K+) status in a "real world" setting and suggest an algorithm on how to introduce the most appropriate drug and set up therapy based on the patients' electrolytes and the existence of congestion.

Impact of Hyperkalemia in Heart Failure and Reduced Ejection Fraction: A Retrospective Study

(1) Background: Hyperkalemia is a common finding in patients with heart failure and reduced ejection fraction (HFrEF), though its prognostic significance is controversial. There is no consensus on optimal potassium levels in these patients. The primary endpoint of this study was to determine the 5-year incidence of hyperkalemia in a cohort of patients with HFrEF. Secondary endpoints were to determine predictors of hyperkalemia and its impact on overall 5-year mortality; (2) Methods: retrospective, longitudinal, single-center observational study of patients with HFrEF followed-up in a specialized unit between 2011 and 2019. Hyperkalemia was considered as potassium concentration > 5.5 mEq/L; (3) Results: Hyperkalemia was observed in 170 (16.8%) of the 1013 patients. The 5-year hyperkalemia-free survival rate was 82.1%. Hyperkalemia was more frequent at the beginning of follow-up. Factors associated with hyperkalemia in the multivariate analysis were baseline potassium (HR 3.13, 95%CI 2.15-4.60; p < 0.001), creatinine clearance (HR 0.99, 95%CI 0.98-0.99; p = 0.013), right ventricular function (HR 0.95, 95%CI 0.91-0.99; p = 0.016) and diabetes mellitus (HR 1.40, 95%CI 1.01-1.96; p = 0.047). The overall survival rate at 5 years was 76.4%. Normal-high potassium levels (5-5.5 mEq/L) were inversely associated with mortality (HR 0.60, 95%CI 0.38-0.94; p = 0.025); (4) Conclusions: Hyperkalemia is a common finding in patients with HFrEF with an impact on the optimization of neurohormonal treatment. In our retrospective study, potassium levels in the normal-high range seem to be safe and are not associated with increased mortality.

A randomized study to compare oral potassium binders in the treatment of acute hyperkalemia

BACKGROUND

The KBindER (K⁺ Binders in Emergency Room and hospitalized patients) clinical trial is the first head-to-head evaluation of oral potassium binders (cation-exchange resins) for acute hyperkalemia therapy.

METHODS

Emergency room and hospitalized patients with a blood potassium level ≥ 5.5 mEq/L are randomized to one of four study groups: potassium binder drug (sodium polystyrene sulfonate, patiromer, or sodium zirconium cyclosilicate) or nonspecific laxative (polyethylene glycol). Exclusion criteria include recent bowel surgery, ileus, diabetic ketoacidosis, or anticipated dialysis treatment within 4 h of treatment drug. Primary endpoints include change in potassium level at 2 and 4 h after treatment drug. Length of hospital stay, next-morning potassium level, gastrointestinal side effects and palatability will also be analyzed. We are aiming for a final cohort of 80 patients with complete data endpoints (20 per group) for comparative statistics including multivariate adjustment for kidney function, diabetes mellitus, congestive heart failure, metabolic acidosis, renin-angiotensin-aldosterone system inhibitor prescription, and treatment with other agents to lower potassium (insulin, albuterol, loop diuretics).

DISCUSSION

The findings from our study will inform decision-making guidelines on the role of oral potassium binders in the treatment of acute hyperkalemia.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04585542 . Registered 14 October 2020.

Electrolyte Imbalance Among Patients With and With No ST-Elevation Myocardial Infarction: A Cohort Study

Electrolytes imbalances are highly prevalent and have shown a high impact on mortality in patients with acute myocardial infarction. These electrolytes imbalance have prognostic value in predicting mortality in patients with acute myocardial infarction. The purpose of this study was to assess the prognostic value of electrolyte imbalances in predicting 1-month mortality among patients with myocardial infarction with and with no ST-elevation. This cohort study was conducted in a referral hospital in the West Bank, Palestine. All patients with confirmed medical diagnosis of acute myocardial infarction and admitted to the medical coronary care unit in the hospital were eligible participants. A convenience sample of 186 participants was obtained. These participants were followed up for 1 month to assess their survival (alive or dead). Demographic and clinical data were recorded by reviewing their health records. The derived data were analyzed using SPSS version 19. About 36% of all patients were found to be hyponatremic, 15% of them have hypokalemia, and 9% of patients had hypocalcemia. There was a significant difference between STEMI and non-STEMI in sodium (t = 4.7, P < .001). A multivariate logistic regression analysis was performed to predict 1-month mortality for patients with myocardial infarction with and with no ST-elevation. The predictors that were found to be significant are sodium (odds ratio [OR] = 0.789, P = .010), calcium (OR = 0.221, P = .014), diastolic blood pressure (OR = 0.933, P = .047), and blood urea nitrogen (OR = 0.821, P = .005). Electrolyte imbalance was highly prevalent among patients with acute myocardial infarction. Hyponatremia and hypocalcemia were present and associated significantly with predicting 1-month mortality. Health care providers should take into consideration the electrolytes of patients with acute myocardial infarction from the first moment of admission and correct them early to maximize the clinical outcomes and survival for patients.

Association of Potassium Level at Discharge with Long-Term Mortality in Hospitalized Patients with Heart Failure

Dyskalemia (hypokalemia and hyperkalemia) is a common comorbidity of heart failure (HF). Although dyskalemia is associated with poor prognosis, different prognostic impacts of hypo- and hyperkalemia remain vastly unclear. This study investigated the association of dyskalemia with prognosis in HF patients, especially the mode of death and left ventricular ejection fraction (LVEF). The multicenter study included 3398 patients hospitalized for HF. Patients were divided into three groups based on serum potassium levels at discharge: hypokalemia (<3.5 mEq/L; n = 115 (3.4%)), normokalemia (3.5−5.0 mEq/L; n = 2960 (87.1%)), and hyperkalemia (≥5.0 mEq/L; n = 323 (9.5%)). Two-year all-cause, cardiac, and non-cardiac mortality was evaluated. Association of serum potassium with two-year mortality demonstrated a U-shaped curve, with a worse prognosis for patients with hypokalemia. All-cause mortality at two-years did not differ among the three groups. Hypokalemia was associated with 2-year cardiac death (adjusted hazard ratio (HR), 2.60; 95% confidence interval (CI), 1.20−5.64) in HF with reduced ejection fraction (HFrEF; LVEF < 40%), but not in non-HFrEF. Regardless of LVEF, hyperkalemia was not independently associated with any mortality. Hypokalemia was independently associated with cardiac death, particularly in HFrEF patients. Such an association was not observed in hyperkalemia regardless of LVEF.

A successful case of electrical storm rescue after acute myocardial infarction

BACKGROUND

Electrical storm (ES) is a heterogeneous clinical emergency that can present with malignant ventricular arrhythmias such as ventricular fibrillation (VF), ventricular tachycardia (VT), requiring the need for cardiac defibrillation. ES is a life-threatening condition with a high mortality rate. Successfully managing ES in the setting of acute myocardial infarction (MI) is expected to be known by physicians on call to reduce in-hospital mortality.

CASE PRESENTATION

A 57-year-old man presenting with acute onset chest pain was found to have an infero-posterior ST-segment elevation myocardial infarction (STEMI) complicated by acute right ventricular MI secondary to total occlusion of the proximal right coronary artery (RCA). The patient developed ES in the form of recurrent VF that was managed successfully with electrical defibrillation, antiarrhythmic therapy with amiodarone and esmolol, endotracheal intubation, sedation, electrolyte replacement, volume resuscitation, comfort care, psychological intervention, and percutaneous coronary intervention (PCI) of the occluded epicardial artery. With these interventions used in quick succession and with the aspiration of a massive RCA thrombus, the patient was reversed to hemodynamic stability, did not have further episodes of VF, and survived the index hospitalization.

CONCLUSION

ES is a rare but fatal complication of acute MI. Residents on night shifts should be better prepared and equipped to deal with this rare condition. We hope our successful experience can benefit physicians on call who take care of acute MI patients that deteriorate with ES.

Targeted potassium levels to decrease arrhythmia burden in high risk patients with cardiovascular diseases (POTCAST): Study protocol for a randomized controlled trial

BACKGROUND

Low plasma potassium (p-K) is associated with increased risk of malignant arrhythmia and observational studies indicate protective effects of p-K in the upper reference level. However, randomized clinical studies are needed to document whether actively increasing p-K to high-normal levels is possible and safe and improves cardiovascular outcomes.

OBJECTIVE

To investigate if increased p-K reduces the risk of malignant arrhythmia and all-cause death in high-risk patients with a cardiovascular disease treated with an implantable cardioverter defibrillator (ICD) for primary or secondary preventive causes. Secondly, to investigate whether high-normal p-K levels can be safely reached and maintained using already available medications and potassium-rich dietary guidance.

METHODS

This is a prospective, randomized, and open-labelled study enrolling patient at high-risk of malignant arrhythmias. According to sample size calculations, 1,000 patients will be randomized 1:1 to either an investigational regiment that aims to increase and maintain p-K at high-normal levels (4.5-5.0 mmol/L) or to usual standard of care and followed for an expected four years. The trial will run until a total of 291 events have occurred providing an α = 0.05 and 1-β = 0.80. The composite primary endpoint includes ventricular tachycardia >125 bpm lasting >30 seconds, any appropriate ICD-therapy, and all-cause mortality. At present, 739 patients have been randomized.

CONCLUSIONS

We present the rationale for the design of the POTCAST trial. The inclusion was initiated 2019 and is expected to be finished 2022. The study will show if easily available treatments to increase p-K may be a new treatment modality to protect against malignant arrythmias.

Dyskalemia in people at increased risk for heart failure: findings from the heart 'OMics' in AGEing (HOMAGE) trial

AIMS

In people at risk of heart failure (HF) enrolled in the Heart 'OMics' in AGEing (HOMAGE) trial, spironolactone reduced circulating markers of collagen synthesis, natriuretic peptides, and blood pressure and improved cardiac structure and function. In the present report, we explored factors associated with dyskalaemia.

METHODS AND RESULTS

The HOMAGE trial was an open-label study comparing spironolactone (up to 50 mg/day) versus standard care in people at risk for HF. After randomization, serum potassium was assessed at 1 and 9 months and was defined as low when ≤3.5 mmol/L (hypokalaemia) and high when ≥5.5 mmol/L (hyperkalaemia). Multivariable logistic regression models were constructed to identify clinical predictors of dyskalaemia. A total of 513 participants (median age 74 years, 75% men, median estimated glomerular filtration rate 71 mL/min/1.73 m² ) had serum potassium available and were included in this analysis. At randomization, 88 had potassium < 4.0 mmol/L, 367 had potassium 4.0-5.0 mmol/L, and 58 had potassium > 5.0 mmol/L. During follow-up, on at least one occasion, a serum potassium < 3.5 mmol/L was observed in 6 (1.2%) and <4.0 mmol/L in 46 (9%) participants, while a potassium > 5.0 mmol/L was observed in 38 (8%) and >5.5 mmol/L in 5 (1.0%) participants. The median (percentile_25-75 ) increase in serum potassium with spironolactone during the study was 0.23 (0.16; 0.29) mmol/L. Because of the low incidence of dyskalaemia, for regression analysis, hypokalaemia and hyperkalaemia thresholds were set at <4.0 and >5.0 mmol/L, respectively. The occurrence of a serum potassium > 5.0 mmol/L during follow-up was positively associated with the presence of diabetes mellitus {odds ratio [OR]: 1.21 [95% confidence interval (CI) 2.14; 3.79]} and randomization to spironolactone (OR: 2.83 [95% CI 1.49; 5.37]). Conversely, the occurrence of a potassium concentration < 4.0 mmol/L was positively associated with the use of thiazides (OR: 2.39 [95% CI 1.32; 4.34]), blood urea concentration (OR: 2.15 [95% CI 1.34; 3.39] per 10 mg/dL), and history of hypertension (OR: 2.32 [95% CI 1.02; 5.29]) and negatively associated with randomization to spironolactone (OR: 0.30 [95% CI 0.18; 0.52]).

CONCLUSIONS

In people at risk for developing HF and with relatively normal renal function, spironolactone reduced the risk of hypokalaemia and, at the doses used, was not associated with the occurrence of clinically meaningful hyperkalaemia.

First 24-Hour Potassium Concentration and Variability and Association with Mortality in Patients Requiring Continuous Renal Replacement Therapy in Intensive Care Units: A Hospital-Based Retrospective Cohort Study

Serum potassium (K+) levels between 3.5 and 5.0 mmol/L are considered safe for patients. The optimal serum K+ level for critically ill patients with acute kidney injury undergoing continuous renal replacement therapy (CRRT) remains unclear. This retrospective study investigated the association between ICU mortality and K+ levels and their variability. Patients aged >20 years with a minimum of two serum K+ levels recorded during CRRT who were admitted to the ICU in a tertiary hospital in central Taiwan between January 01, 2010, and April 30, 2021 were eligible for inclusion. Patients were categorized into different groups based on their mean K+ levels: <3.0, 3.0 to <3.5, 3.5 to <4.0, 4.0 to <4.5, 4.5 to <5.0, and ≥5.0 mmol/L; K+ variability was divided by the quartiles of the average real variation. We analyzed the association between the particular groups and in-hospital mortality by using Cox proportional hazard models. We studied 1991 CRRT patients with 9891 serum K+ values recorded within 24 h after the initiation of CRRT. A J-shaped association was observed between serum K+ levels and mortality, and the lowest mortality was observed in the patients with mean K+ levels between 3.0 and 4.0 mmol/L. The risk of in-hospital death was significantly increased in those with the highest variability (HR and 95% CI = 1.61 [1.13−2.29] for 72 h mortality; 1.39 [1.06−1.82] for 28-day mortality; 1.43 [1.11−1.83] for 90-day mortality, and 1.31 [1.03−1.65] for in-hospital mortality, respectively). Patients receiving CRRT may benefit from a lower serum K+ level and its tighter control. During CRRT, progressively increased mortality was noted in the patients with increasing K+ variability. Thus, the careful and timely correction of dyskalemia among these patients is crucial.

Electrolyte’s imbalance role in atrial fibrillation: Pharmacological management

The contribution of the perpetuation of atrial fibrillation is caused by electrical remodeling in which calcium, sodium and potassium channels could refer to changes in the ion channel protein expression, development of fibrosis, gene transcription and ion channel redistribution. Calcium and magnesium could influence the risk of atrial fibrillation which is the leading cause of cardiac death, heart failure and ischemic stroke. The elevated serum concentration of calcium had a higher range of in-patient’s mortality, increased total cost of hospitalization and increased length of hospital stay as compared to those without hypercalcemia in atrial fibrillation patients. Moreover, chloride channels could affect homeostasis, atrial myocardial metabolism which may participate in the development of atrial fibrillation. Up to a 50% risk of incidence of AF are higher in which left ventricular hypertrophy, sudden cardiovascular death and overall mortality relate to a low serum magnesium level. Additionally, magnesium prevents the occurrence of AF after cardiac surgery, whereas greater levels of serum phosphorus in the large population-based study and the related calcium–phosphorus products were linked with a greater incidence of AF. Numerous clinical studies had shown the high preoperative risk of AF that is linked with lower serum potassium levels. The conventional risk factor of increased risk of new onset of AF events could independently link with high dietary sodium intake which enhances the fibrosis and inflammation in the atrium but the mechanism remains unknown. Many drugs were used to maintain the electrolyte imbalance in AF patients.

Association of serum potassium with decline in residual kidney function in incident hemodialysis patients

BACKGROUND

Hyperkalemia is associated with kidney function decline in patients with non-dialysis dependent chronic kidney disease, but this relationship is unclear for residual kidney function among hemodialysis (HD) patients.

METHODS

We conducted a retrospective cohort study of 6655 patients who started HD from January 2007 to December 2011 and who had data on renal urea clearance (KRU). Serum potassium levels were stratified into four groups (i.e. ≤4.0, >4.0 to ≤ 4.5, >4.5 to ≤ 5.0, >5.0 mEq/L) and 1-year KRU slope for each group was estimated by a linear mixed-effects model.

RESULTS

Higher serum potassium was associated with greater decline in KRU, and the greatest decrease in KRU (-0.20, 95% CI -0.50, -0.06) was observed for baseline potassium > 5.0 mEq/L in the fully adjusted model. Mediation analysis showed that KRU slope mediated 1.78% of the association between serum potassium and mortality.

CONCLUSIONS

In conclusion, hyperkalemia is associated with decline in residual kidney function amongst incident HD patients. These findings may have important clinical implications in the management of hyperkalemia in advanced CKD if confirmed in additional studies including clinical trials.

Associations of Nutritional Behavior and Gut Microbiota with the Risk of COVID-19 in Healthy Young Adults in Poland

The numerous consequences of the coronavirus disease 2019 (COVID-19) pandemic in healthy young people and the lack of clarity as to the long-term disease outcomes have spurred the search for risk factors for SARS-CoV-2 infection. We aimed to evaluate the associations of nutritional behaviors, gut microbiota, and physical activity with the risk of COVID-19 in healthy young nonobese people. Data on body composition, anthropometric measurements, physical activity, dietary intake, and gut microbiota were obtained from 95 adults (mean age, 34.66 ± 5.76 years). A balanced diet rich in vegetables and fruit, including nuts, wholegrain cereal products, and legumes, covers the need for vitamins and minerals. Such a diet can be an effective measure to reduce the risk of COVID-19 in nonobese healthy physically active young people with normal immune function. People with balanced diet and an average daily consumption of >500 g of vegetables and fruit and >10 g of nuts had an 86% lower risk of COVID-19 compared with those whose diet was not balanced and who consumed lower amounts of these products. It is well documented that proper nutrition, physical activity, and maintenance of normal weight facilitate good health by ensuring optimal immune function. The beneficial effects of these interventions should be strongly emphasized during the COVID-19 pandemic.

Association of serum potassium level with early and late mortality in very elderly patients with acute kidney injury

Background

The kidneys play a central role in serum potassium (K ⁺) homeostasis, and their dysfunction leads to electrolyte disorders. We aimed to examine the relationship between different levels of K ⁺ and mortality among very elderly patients with acute kidney injury (AKI).

Methods

We retrospectively enrolled very elderly patients (≥75 years) with AKI from the hospital information system of the Chinese PLA General Hospital from January 1, 2007 to December 31, 2018. All-cause mortality was examined according to six predefined K ⁺ levels: <3.50 mmol/L, 3.50-3.79 mmol/L, 3.80-4.09 mmol/L, 4.10-4.79 mmol/L, 4.80-5.49 mmol/L, and ≥5.50 mmol/L. We estimated the risk of all-cause mortality using the multivariable adjusted Cox proportional hazard model with the normal K ⁺ level at 3.50-3.79 mmol/L as a reference.

Results

In total, 747 patients were deemed suitable for the final evaluation. The median age of the 747 participants was 88 (84-91) years. After 90 days, the mortality rates in the six strata were 28.3%, 21.9%, 30.1%, 35.4%, 45.2%, and 58.3%, respectively. In the multivariable adjusted analysis, patients with K ⁺ levels of 4.10-4.79 mmol/L (hazard ratio [HR]: 1.638; 95% confidence interval [CI]: 1.016-2.642), 4.80-5.49 mmol/L (HR: 2.585; 95% CI: 1.524-4.384), and ≥5.50 mmol/L (HR: 2.587; 95% CI: 1.495-4.479) had an increased risk of all-cause mortality. After 1 year, the mortality rates in the six strata were 44.8%, 41.1%, 45.1%, 51.8%, 63.1%, and 76.3%, respectively. In the multivariable adjusted analysis, patients with K ⁺ levels of 4.10-4.79 mmol/L (HR: 1.452; 95% CI: 1.014-2.079), 4.80-5.49 mmol/L (HR: 2.151; 95% CI: 1.427-3.241), and ≥5.50 mmol/L (HR: 2.341; 95% CI: 1.514-3.620) had an increased risk of all-cause mortality.

Conclusion

Increased serum K ⁺ levels, including levels of 4.10-5.49 mmol/L and ≥5.50 mmol/L, were associated with a significantly increased short- and long-term risk of death. Serum K ⁺ has the potential to be a marker of disease severity among very elderly patients with AKI.

Predictive impacts of chronic kidney disease and cardiac sympathetic nervous activity on lethal arrhythmic events in chronic heart failure

BACKGROUND

The clinical implications of chronic kidney disease (CKD) and cardiac sympathetic nervous activity (CSNA) regarding lethal arrhythmic events have not yet been fully elucidated in patients with chronic heart failure (CHF). We hypothesized that the combination of CKD and abnormal CSNA, assessed by 123 I-metaiodobenzylguanidine (123 I-MIBG) scintigraphy, may provide useful prognostic information for lethal arrhythmic events.

METHODS

We studied 165 consecutive hospitalized CHF patients without dialysis. Cardiac 123 I-MIBG scintigraphy was performed in a clinically stable condition, and abnormal CSNA was defined as a late heart-to-mediastinum ratio of <1.6. CKD was defined as an estimated glomerular filtration rate of <60 ml/min/1.73 m2 . We then investigated the incidence of lethal arrhythmic events (sustained ventricular tachyarrhythmia, appropriate implantable cardioverter-defibrillator therapy, or sudden cardiac death).

RESULTS

During a median follow-up of 5.3 years, lethal arrhythmic events were observed in 40 patients (24.2%). The patients were divided into four groups according to the presence of CKD and CSNA abnormality: non-CKD/normal CSNA (n = 52), CKD/normal CSNA (n = 39), non-CKD/abnormal CSNA (n = 33), and CKD/abnormal CSNA (n = 41). Kaplan-Meier analysis showed that CKD/abnormal CSNA had the highest event rate (log-rank p = .004). Additionally, the Cox proportional hazard analysis revealed that CKD/abnormal CSNA was a predictor for lethal arrhythmic events compared with non-CKD/normal CSNA (hazard ratio, 5.368, p = .001). However, the other two groups did not show significant differences compared with the non-CKD/normal CSNA group.

CONCLUSIONS

The combination of CKD and abnormal CSNA, assessed by 123 I-MIBG scintigraphy, had a high predictive value for lethal arrhythmic events in patients with CHF.

Arrhythmic Risk Assessment of Hypokalaemia Using Human Pluripotent Stem Cell-Derived Cardiac Anisotropic Sheets

Introduction: Hypokalaemia, defined as an extracellular concentration of K⁺ below 3.5 mM, can cause cardiac arrhythmias by triggered or re-entrant mechanisms. Whilst these effects have been reported in animal and human stem cell-based models, to date there has been no investigation in more complex structures such as the human ventricular cardiac anisotropic sheet (hvCAS). Here, we investigated arrhythmogenicity, electrophysiological, and calcium transient (CaT) changes induced by hypokalaemia using this bioengineered platform.

Methods: An optical mapping technique was applied on hvCAS derived from human pluripotent stem cells to visualize electrophysiological and CaT changes under normokalaemic (5 mM KCl) and hypokalaemic (3 mM KCl) conditions.

Results: Hypokalaemia significantly increased the proportion of preparations showing spontaneous arrhythmias from 0/14 to 7/14 (Fisher’s exact test, p = 0.003). Hypokalaemia reduced longitudinal conduction velocity (CV) from 7.81 to 7.18 cm⋅s⁻¹ (n = 9, 7; p = 0.036), transverse CV from 5.72 to 4.69 cm⋅s⁻¹ (n = 12, 11; p = 0.030), prolonged action potential at 90% repolarization (APD₉₀) from 83.46 to 97.45 ms (n = 13, 15; p < 0.001), increased action potential amplitude from 0.888 to 1.195 ΔF (n = 12, 14; p < 0.001) and CaT amplitude from 0.76 to 1.37 ΔF (n = 12, 13; p < 0.001), and shortened effective refractory periods from 242 to 165 ms (n = 12, 13; p < 0.001).

Conclusion: Hypokalaemia exerts pro-arrhythmic effects on hvCAS, which are associated with alterations in CV, repolarization, refractoriness, and calcium handling. These preparations provide a useful platform for investigating electrophysiological substrates and for conducting arrhythmia screening.

Factors Associated with Congenital Heart Disease in Severely Malnourished Children under Five and Their Outcomes at an Urban Hospital, Bangladesh

Congenital heart disease (CHD) is one of the most common types of birth defect with a high morbidity and mortality, particularly in severely malnourished children under five. In this study, we aim to identify the predicting factors for CHD and their outcomes. 694 malnourished children under five years of age admitted between April 2015 and December 2017 constituted the study population. Of them, 64 were cases of CHD, and by comparison 630 were without CHD. CHD was diagnosed clinically and confirmed by echocardiogram. 64% of the cases had a single defect. Cases were more likely to be present with diarrhea, cough, respiratory distress, cyanosis, hypoxemia, hypoglycemia and hypernatremia on admission. The cases also had a high proportion of severe sepsis, bacteremia, heart failure, respiratory failure and death, compared to those without CHD. Cough (95% CI = 1.09–18.92), respiratory distress (95% CI = 1.46–5.39) and hypoxemia (95% CI = 1.59–6.86) were found to be the independent predictors for CHD after regression analysis, and their early identification might be helpful to lessen ramifications, including mortality, in such populations, especially in resource-limited settings.

Hyperkalemia in Patients With Left Ventricular Assist Devices

Background: Both hypo- and hyperkalemia are associated with adverse events in heart failure patients. Their effects on patients with left ventricular assist devices (LVADs) remains unknown.

Methods and Results: The cohort included consecutive patients undergoing LVAD implantation between 2014 and 2018. In all, 170 patients (median age 56 years; 117 males) were stratified according to serum potassium levels 1 month after implantation into 3 groups: hypokalemia (<3.5 mEq/L; n=15), normokalemia (n=146), and hyperkalemia (>5.0 mEq/L; n=9). Compared with the normokalemia group, the adjusted hazard ratios for 1-year mortality were 0.91 (95% confidence interval [CI] 0.21–3.92) for hypokalemia and 4.14 (95% CI 1.47–11.65) for hyperkalemia. In the hyperkalemia group, the prevalence of renin-angiotensin-aldosterone system inhibitors decreased and serum potassium levels normalized following the first month.

Conclusions: Hyperkalemia was associated with increased mortality during LVAD support. Management of serum potassium needs further investigation.

Effect of dynamic stratified potassium supplementation in elderly patients with chronic heart failure and moderate to severe hypokalaemia-a randomised, controlled trial

OBJECTIVE

To compare the effectiveness of dynamic stratified potassium supplementation at high concentrations with enteral potassium supplementation in older patients with chronic heart failure and moderate to severe hypokalaemia.

METHODS

We performed a single-centre, short-term, randomised, controlled, open-labelled, clinical trial, and patients were randomly allocated to the control or intervention group. The intervention group received intermittent infusions of 30 mmol/100 mL potassium chloride. In the control group, 10% potassium chloride was administered orally in a bolus dose. Short-term efficacy and adverse events were compared.

RESULTS

The intervention group received less potassium than that in the control group. T-wave normalisation and U-wave disappearance occurred sooner in the intervention group than in the control group after potassium supplementation. The rate of increase in potassium concentrations gradually became similar in both groups. The initial blood potassium concentration, method of potassium supplementation, potassium supplement dose, and 24-hour urinary potassium excretion significantly affected the rate of increase in blood potassium concentrations after supplementation.

CONCLUSIONS

The efficacy of enteral potassium supplementation is equivalent to that of supplementation with high intravenous potassium concentrations in elderly patients with chronic heart failure and moderate to severe hypokalaemia. High intravenous potassium concentrations may lead to a superior potassium recovery rate.

Low serum potassium levels are associated with the risk of atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) is the most common sustained arrhythmia in clinical practice. AF is associated with approximately a threefold to fivefold increased risk for stroke. Hypokalaemia is associated with ventricular arrhythmias and cardiac arrest. Little is known about the association of serum potassium with atrial fibrillation.

AIMS

The aims of this study are to assess the association of low serum potassium (hypokalaemia) and the risk of AF.

METHODS

Retrospective data were collected for all patients' records, who were hospitalised at department of Internal Medicine of Ziv Medical Centre, Safed, Israel, from January 2013 to December 2017 with AF. Clinical data were obtained from patient's hospital records. We excluded those who were pregnant, diagnosed with malignancy and those with thyrotoxicosis. Control group consisted of patients who were hospitalised in the same period with normal sinus rhythm (NSR). We compared between the two groups in term of age, gender, comorbidities and serum levels of potassium and magnesium.

RESULTS

We enrolled 281 subjects with AF who responded to our study purposes. The control group consistend of 260 with NSR. Hypokalaemia of less than 3.5 mmol/l was found in 16% in the study group vs. 8.4% in control group, p = 0.001. Multivariate regression analysis showed that OR 2.08, 95% CI (1.378-3.138), p = 0.01, and hypokalaemia < 3.5 mmol/l OR1.827, 95%CI (1.50-3.179), p = 0.02 were found to be associated with atrial fibrillation.

CONCLUSION

We found that low serum potassium levels of less than 3.5 mmol/l are associted with increased risk of AF.

Simple Laboratory Test-Based Risk Scores in Coronary Catheterization: Development, Validation, and Comparison to Conventional Risk Factors

BACKGROUND

We developed and validated laboratory test-based risk scores (i.e., lab risk scores) to reclassify mortality risk among patients undergoing their first coronary catheterization.

METHODS

Patients were catheterized between 2009 and 2015 in Calgary, Alberta, Canada (n = 14 135, derivation cohort), and in Edmonton, Alberta, Canada (n = 12 143, validation cohort). Logistic regression with group LASSO (least absolute shrinkage and selection operator) penalty was used to select quintiles of the last laboratory tests (red blood cell count, mean corpuscular hemoglobin concentration, mean corpuscular hemoglobin, mean corpuscular volume, red cell distribution width, platelet count, total white blood cell count, plasma sodium, potassium, chloride, CO2, international normalized ratio, estimated glomerular filtration rate) performed <30 days before catheterization and by age and sex that were significantly associated with death ≤60  and >60 days after catheterization. Follow-up was until 2016. Risk scores were developed from significant tests, internally validated in Calgary among bootstrap samples and externally validated in Edmonton after recalibration using coefficients developed in Calgary. Interaction tests were performed, and net reclassification improvement vs conventional demographic and clinical risk factors was determined.

RESULTS

Lab risk scores were strongly associated with mortality (29-40× for top vs bottom quintile, P for trends <0.01), had good discrimination and were well calibrated in Calgary (C = 0.80-0.85, slope = 0.99-1.01) and Edmonton (C = 0.80-0.82; slope = 1.02-1.05)-similar to demographic and clinical risk factors alone. Associations were attenuated by several comorbidities; however, scores appropriately reclassified 11%-20% of deaths (both follow-up periods) and 6%-9% of survivors (>60 days) after catheterization vs demographic and clinical risk factors.

CONCLUSIONS

In 2 populations of patients undergoing their first coronary catheterization, risk scores based on simple laboratory tests were as powerful as a combination of demographic and clinical risk factors in predicting mortality. Lab risk scores should be used for patients undergoing coronary catheterization.

Low Food Consumption Interferes with the Nutritional Status of Surgical Patients with Neoplasia of the Gastrointestinal Tract

Nutritional support strongly influence the nutritional status of the surgical neoplastic patients. This study aimed to evaluate the influence of food consumption on the perioperative nutritional status of hospitalized patients with neoplasia of the upper (UGIT) and lower (LGIT) gastrointestinal tract. Methods: Observational, longitudinal, and prospective study. Data collected: food consumption, Subjective Global Assessment, anthropometry, laboratory tests. Results: Eighty patients were followed up: 43 (54%) in the UGIT and 37 (46%) in the LGIT. The consumption in the perioperative period was lower than the usual consumption in the UGIT and LGIT groups, respectively, of energy (14.2 ± 6.5; 22.8 ± 11.2 Kcal/kg/d, p < 0.001; 13.6 ± 1.2; 19.0 ± 2.0 Kcal/kg/d; p = 0.014), protein (1.1 ± 0.7; 0.6 ± 0.3 g/kg/d, p < 0.001; 0.8 ± 0.1; 0.5 ± 0.1 g/kg/d; p = 0.058), selenium, zinc and copper. Most patients presented in the UGIT and LGIT groups, respectively, worsening malnutrition and muscle depletion according to the Subjective Global Assessment (61.9%; 51.4%) and hypoalbuminemia, mainly in the UGIT in the postoperative. Conclusion: Low food consumption during the perioperative period associated with prolongation of the postoperative fasting period worsens the nutritional status of patients undergoing surgery of the gastrointestinal tract for neoplasia, especially in the UGIT group.

Serum potassium variability is associated with increased mortality in a large cohort of hospitalized patients

BACKGROUND

Few studies have examined the role of serum potassium concentrations [K+] variability on clinical outcomes is still poorly investigated. Aim of our study was to analyze the association between serum potassium concentrations ([K+]) disorders, with focus on [K+] variability, and mortality in a large, unselected cohort of hospitalized patients.

METHODS

We performed a retrospective observational cohort study on the inpatient population admitted to Fondazione Policlinico Universitario A. Gemelli IRCCS between January 1, 2010 and December 31, 2014 with inclusion of adult patients with [K+] measurements ≥2. The outcome of interest was in-hospital mortality. The exposures of interest were [K+] fluctuations and hypo-hyperkalemia and mixed dyskalemia during hospital stay. [K+] variability was evaluated using the coefficient of variation (CV). Logistic regression models were fitted to obtain odds ratios (ORs) and 95% confidence intervals (CIs) for the association between the exposures of interest and in-hospital death.

RESULTS

Overall, 64,507 patients met our inclusion criteria. During a median follow-up of 8 days, 965 patients (1.5%) died. Multivariable adjusted logistic models suggested a higher risk for death in patients in the 3rd (OR 1.45, 95% CI 1.13, 1.88, p = 0.003) and 4th (OR 3.30, 95% CI 2.64, 4.16, p < 0.001) highest quartiles of [K+] CV compared with those in the lowest quartile with a significant linear trend across quartiles (p-trend <0.001) Results did not change after restricting the analyses to patients with normokaliemia (NK). All [K+] disorders were independently associated with an increased risk of in-hospital death compared with NK.

CONCLUSIONS

High [K+] variability is an independent risk factor of in-hospital mortality, even within the normal [K+] range.

A tale of two extremities: A dynamic case of Covid-19 induced hypokalemia and bradycardia leading into Torsade's de pointes

INTRODUCTION

As researchers and academics around the world scramble ahead to dissect and analyse every aspect of the SARS-CoV2 virus, one such study explored the various underlying electrolyte abnormalities that were precipitated in patients suffering from a confirmed COVID-19 infection. A significant proportion of such patients were noted to be hypokalemic. Hypokalemia can be life threatening as it is known to cause cardiac arrhythmia.

CASE PRESENTATION

Our encounter with said presentation was incidental. The on-call medical team was involved in a cardiac arrest call for a 74-year -old gentleman who developed torsades de pointes, Retrospective analysis of the clinical picture pointed out the fact that he was found to be persistently hypokalemic and bradycardic solely triggered as a result of COVID-19.

CONCLUSION

Although initially thought to be a pulmonary disease but along with time extra-pulmonary manifestations of Covid-19 has demonstrated significant consequences. Electrolyte abnormalities and cardiac dysfunction are examples of such extra-pulmonary pathologies. Therefore, it is important to keep close monitoring for such abnormalities otherwise could lead into life threatening arrythmias.

Discovery of MK-8153, a Potent and Selective ROMK Inhibitor and Novel Diuretic/Natriuretic

A renal outer medullary potassium channel (ROMK, Kir1.1) is a putative drug target for a novel class of diuretics with potential for treating hypertension and heart failure. Our first disclosed clinical ROMK compound, 2 (MK-7145), demonstrated robust diuresis, natriuresis, and blood pressure lowering in preclinical models, with reduced urinary potassium excretion compared to the standard of care diuretics. However, 2 projected to a short human half-life (∼5 h) that could necessitate more frequent than once a day dosing. In addition, a short half-life would confer a high peak-to-trough ratio which could evoke an excessive peak diuretic effect, a common liability associated with loop diuretics such as furosemide. This report describes the discovery of a new ROMK inhibitor 22e (MK-8153), with a longer projected human half-life (∼14 h), which should lead to a reduced peak-to-trough ratio, potentially extrapolating to more extended and better tolerated diuretic effects.

Immediate and Delayed Response of Simulated Human Atrial Myocytes to Clinically-Relevant Hypokalemia

Although plasma electrolyte levels are quickly and precisely regulated in the mammalian cardiovascular system, even small transient changes in K⁺, Na⁺, Ca²⁺, and/or Mg²⁺ can significantly alter physiological responses in the heart, blood vessels, and intrinsic (intracardiac) autonomic nervous system. We have used mathematical models of the human atrial action potential (AP) to explore the electrophysiological mechanisms that underlie changes in resting potential (V_r) and the AP following decreases in plasma K⁺, [K⁺]_o, that were selected to mimic clinical hypokalemia. Such changes may be associated with arrhythmias and are commonly encountered in patients (i) in therapy for hypertension and heart failure; (ii) undergoing renal dialysis; (iii) with any disease with acid-base imbalance; or (iv) post-operatively. Our study emphasizes clinically-relevant hypokalemic conditions, corresponding to [K⁺]_o reductions of approximately 1.5 mM from the normal value of 4 to 4.5 mM. We show how the resulting electrophysiological responses in human atrial myocytes progress within two distinct time frames: (i) Immediately after [K⁺]_o is reduced, the K⁺-sensing mechanism of the background inward rectifier current (I_K1) responds. Specifically, its highly non-linear current-voltage relationship changes significantly as judged by the voltage dependence of its region of outward current. This rapidly alters, and sometimes even depolarizes, V_r and can also markedly prolong the final repolarization phase of the AP, thus modulating excitability and refractoriness. (ii) A second much slower electrophysiological response (developing 5-10 minutes after [K⁺]_o is reduced) results from alterations in the intracellular electrolyte balance. A progressive shift in intracellular [Na⁺]_i causes a change in the outward electrogenic current generated by the Na⁺/K⁺ pump, thereby modifying V_r and AP repolarization and changing the human atrial electrophysiological substrate. In this study, these two effects were investigated quantitatively, using seven published models of the human atrial AP. This highlighted the important role of I_K1 rectification when analyzing both the mechanisms by which [K⁺]_o regulates V_r and how the AP waveform may contribute to "trigger" mechanisms within the proarrhythmic substrate. Our simulations complement and extend previous studies aimed at understanding key factors by which decreases in [K⁺]_o can produce effects that are known to promote atrial arrhythmias in human hearts.

Potassium Metabolism and Management in Patients with CKD

Potassium (K), the main cation inside cells, plays roles in maintaining cellular osmolarity and acid-base equilibrium, as well as nerve stimulation transmission, and regulation of cardiac and muscle functions. It has also recently been shown that K has an antihypertensive effect by promoting sodium excretion, while it is also attracting attention as an important component that can suppress hypertension associated with excessive sodium intake. Since most ingested K is excreted through the kidneys, decreased renal function is a major factor in increased serum levels, and target values for its intake according to the degree of renal dysfunction have been established. In older individuals with impaired renal function, not only hyperkalemia but also hypokalemia due to anorexia, K loss by dialysis, and effects of various drugs are likely to develop. Thus, it is necessary to pay attention to K management tailored to individual conditions. Since abnormalities in K metabolism can also cause lethal arrhythmia or sudden cardiac death, it is extremely important to monitor patients with a high risk of hyper- or hypokalemia and attempt to provide early and appropriate intervention.

Update on management of hypokalemia and goals for the lower potassium level in patients with cardiovascular disease: A review in collaboration with the European Society of Cardiology Working Group on Cardiovascular Pharmacotherapy

Hypokalaemia is common in patients with cardiovascular disease. In this review, we emphasize the importance of tight potassium regulation in patients with cardiovascular disease based on findings from observational studies. To enhance the understanding, we also describe the mechanisms of potassium homeostasis maintenance, the most common causes of hypokalaemia and present strategies for monitoring and management of low potassium levels. We propose elevation of potassium in asymptomatic patients with lower normal concentrations and concurrent cardiovascular disease. These proposals are intended to assist clinicians until more evidence is available.

Management of hyperkalemia during treatment with mineralocorticoid receptor blockers: findings from esaxerenone

The nonsteroidal mineralocorticoid receptor (MR) blocker esaxerenone has demonstrated good antihypertensive activity in a variety of patients, including those with uncomplicated grade I-III hypertension, hypertension with moderate renal dysfunction, hypertension with type 2 diabetes mellitus with albuminuria, and hypertension associated with primary aldosteronism. Hyperkalemia has long been recognized as a potential side effect occurring during treatment with MR blockers, but there is a lack of understanding and guidance about the appropriate management of hyperkalemia during antihypertensive therapy with MR blockers, especially in regard to the newer agent esaxerenone. In this article, we first highlight risk factors for hyperkalemia, including advanced chronic kidney disease, diabetes mellitus, cardiovascular disease, age, and use of renin-angiotensin-aldosterone system inhibitors. Next, we examine approaches to prevention and management, including potassium monitoring, diet, and the use of appropriate therapeutic techniques. Finally, we summarize the currently available data for esaxerenone and hyperkalemia. Proper management of serum potassium is required to ensure safe clinical use of MR blockers, including awareness of at-risk patient groups, choosing appropriate dosages for therapy initiation and dosage titration, and monitoring of serum potassium during therapy. It is critical that physicians take such factors into consideration to optimize MR blocker therapy in patients with hypertension.

Admission serum potassium levels and prognosis of vasospastic angina

Hypokalemia is a common electrolyte disturbance and is related to poor prognosis in patients with cardiovascular disease. However, the role of hypokalemia in patients with vasospastic angina (VSA) has not yet been studied. The present study enrolled 1454 patients diagnosed with VSA according to ergonovine provocation test results and available admission serum potassium data. The primary outcome was a composite of cardiac death, acute coronary syndrome, and new-onset life-threatening arrhythmia. Based on a hypokalemia definition as serum potassium concentration ≤ 3.5 mEq/L, the hypokalaemia group included 70 patients (4.8%). The median potassium levels were 3.4 mEq/L [interquartile range (IQR) 3.3-3.5] in the hypokalemia group and 4.1 mEq/L (IQR 3.9-4.3) in the no-hypokalemia group. The median follow-up duration was 764 days. Primary outcomes occurred in seven patients (10.0%) in the hypokalemia group and 51 patients (3.7%) in the no-hypokalemia group. The Kaplan-Meier analysis showed a higher cumulative incidence of primary outcomes in the hypokalemia group compared to that in the no-hypokalemia group (log-rank P = 0.014). Multivariate Cox regression analysis also showed that hypokalemia was an independent predictor of primary outcomes. In conclusion, hypokalemia at admission was associated with adverse clinical outcomes in VSA.

Diuretic-induced hypokalaemia: an updated review

Diuretic-induced hypokalaemia is a common and potentially life-threatening adverse drug reaction in clinical practice. Previous studies revealed a prevalence of 7%-56% of hypokalaemia in patients taking thiazide diuretics. The clinical manifestations of hypokalaemia due to diuretics are non-specific, varying from asymptomatic to fatal arrhythmia. Diagnosis of hypokalaemia is based on the level of serum potassium. ECG is useful in identifying the more severe consequences. A high dosage of diuretics and concomitant use of other drugs that increase the risk of potassium depletion or cardiac arrhythmias can increase the risk of cardiovascular events and mortality. Thiazide-induced potassium depletion may cause dysglycaemia. The risk of thiazide-induced hypokalaemia is higher in women and in black people. Reducing diuretic dose and potassium supplementation are the most direct and effective therapies for hypokalaemia. Combining with a potassium-sparing diuretic or blocker of the renin-angiotensin system also reduces the risk of hypokalaemia. Lowering salt intake and increasing intake of vegetables and fruits help to reduce blood pressure as well as prevent hypokalaemia.

Serum potassium and outcomes in heart failure with preserved ejection fraction: a post-hoc analysis of the PARAGON-HF trial

AIMS

The relationship between serum potassium concentration and outcomes in patients with heart failure and preserved ejection fraction (HFpEF) is not well-established. The aim of this study was to explore the association between serum potassium and clinical outcomes in the PARAGON-HF trial in which 4822 patients with HFpEF were randomised to treatment with sacubitril/valsartan or valsartan.

METHODS AND RESULTS

The relationship between serum potassium concentrations and the primary study composite outcome of total (first and recurrent) heart failure hospitalisations and cardiovascular death was analysed. Hypo-, normo-, and hyperkalaemia were defined as serum potassium <4 mmol/L, 4-5 mmol/L and >5 mmol/L, respectively. Both screening and time-updated potassium (categorical and continuous spline-transformed) were studied. Patient mean age was 73 years and 52% were women. Patients with higher baseline potassium more often had an ischaemic aetiology and diabetes and mineralocorticoid receptor antagonist treatment. Compared with normokalaemia, both time-updated (but not screening) hypo- and hyperkalaemia were associated with a higher risk of the primary outcome [adjusted hazard ratio (HR) for hypokalaemia 1.55, 95% confidence interval (CI) 1.30-1.85; P < 0.001, and for hyperkalaemia HR 1.21, 95% CI 1.02-1.44; P = 0.025]. Hypokalaemia had a stronger association with a higher risk of all-cause, cardiovascular and non-cardiovascular death than hyperkalaemia. The association of hypokalaemia with increased risk of all-cause and cardiovascular death was most marked in participants with impaired kidney function (interaction P < 0.05). Serum potassium did not significantly differ between sacubitril/valsartan and valsartan throughout the follow-up.

CONCLUSIONS

Both hypo- and hyperkalaemia were associated with heart failure hospitalisation but only hypokalaemia was associated with mortality, especially in the context of renal impairment. Hypokalaemia was as strongly associated with death from non-cardiovascular causes as with cardiovascular death. Collectively, these findings suggest that potassium disturbances are a more of a marker of HFpEF severity rather than a direct cause of death.

Potassium variability during hospitalization and outcomes after discharge in patients with acute myocardial infarction

BACKGROUND

The variability of metabolic biomarkers has been determined to provide incremental prognosis information, but the implications of electrolyte variability remained unclear.

METHODS

We investigate the relationships between electrolyte fluctuation and outcomes in survivors of acute myocardial infarction (n = 4386). Ion variability was calculated as the coefficient of variation, standard deviation, variability independent of the mean (VIM) and range. Hazard ratios (HR) were estimated using the multivariable-adjusted Cox proportional regression method.

RESULTS

During a median follow-up of 12 months, 161 (3.7%) patients died, and heart failure occurred in 550 (12.5%) participants after discharge, respectively. Compared with the bottom quartile, the highest quartile potassium VIM was associated with increased risks of all-cause mortality (HR = 2.35, 95% CI: 1.36-4.06) and heart failure (HR = 1.32, 95% CI: 1.01-1.72) independent of cardiac troponin I (cTnI), N terminal pro B type natriuretic peptide (NT-proBNP), infarction site, mean potassium and other traditional factors, while those associations across sodium VIM quartiles were insignificant. Similar trend remains across the strata of variability by other three indices. These associations were consistent after excluding patients with any extreme electrolyte value and diuretic use.

CONCLUSIONS

Higher potassium variability but not sodium variability was associated with adverse outcomes post-infarction. Our findings highlight that potassium variability remains a robust risk factor for mortality regardless of clinical dysnatraemia and dyskalaemia.

LONG-TERM MORTALITY AND TRAJECTORY OF POTASSIUM MEASUREMENTS FOLLOWING AN EPISODE OF ACUTE SEVERE HYPERKALEMIA

BACKGROUND

Hyperkalemia is a common condition in patients with comorbidities such as chronic kidney disease (CKD) or congestive heart failure. Moreover, severe hyperkalemia is a potentially life-threatening condition that is associated with a higher risk of adverse clinical events such as ventricular arrhythmias and sudden cardiac death. Currently, data regarding the prognostic implications of chronic hyperkalemia are available; however, the information about the long-term clinical consequences after an episode of severe hyperkalemia remains scarce. The objective of the study was to evaluate the association between the trajectory of potassium measurements in patients with acute hyperkalemia and long-term all-cause mortality.

METHODS

This is a retrospective observational study that included patients with acute severe hyperkalemia (K > 6 mEq/L) without hemolysis in the emergency room of Dr. Peset University Hospital in Valencia, Spain searching the lab database from January 2016 to March 2017. The multivariable-adjusted association of serum potassium with mortality was assessed by using comprehensive state-of-the-art regression methods that can accommodate time-dependent exposure modelling.

RESULTS

We found 172 episodes of acute hyperkalemia in 160 patients in the emergency room. The mean age of the sample was 77 ± 12 years and 60.5% were males. The most frequent comorbidities were CKD (71.2%), heart failure (35%) and diabetes mellitus (56.9%). Only 11.9% of the patients were on chronic dialysis. A quarter of the patients did not have previous CKD making hyperkalemia as an unpredictable life-threatening complication. During the acute episode, mean potassium and eGFR were 6.6 ± 0.6 (range: 6,1-9,2), and eGFR: 23 ± 16 (r : 2-84). After a median follow-up of 17.3 (IQR: 2.2-23.7) months, 68 patients died (42.5%). Recurrences of hyperkalemia (K > 5.5 mEq/L) were detected in 39.5%% of the patients who were monitored during follow-up. We found that previous potassium levels during an acute severe hyperkalemia episode were not predictors of mortality. Conversely, the post-discharge longitudinal trajectories of potassium were able to predict all-cause mortality (overall p-value = 0.0015). The effect of transitioning from hyperkalemia to normokalaemia (K > 5.5 to K ≤ 5.5 after the acute episode was significant and inversely associated with the risk of mortality.

CONCLUSION

The potassium levels prior to a severe hyperkalemic event do not predict mortality. Conversely, following an episode of acute severe hyperkalemia, serial kinetic of potassium trajectories predicts the risk of death. Further evidence is needed to confirm these findings and clarify the optimal long-term management of these patients.

Abnormalities of Potassium in Heart Failure: JACC State-of-the-Art Review

Potassium (K⁺) is the most abundant cation in humans and is essential for normal cellular function. Alterations in K⁺ regulation can lead to neuromuscular, gastrointestinal, and cardiac abnormalities. Dyskalemia (i.e., hypokalemia and hyperkalemia) in heart failure is common because of heart failure itself, related comorbidities, and medications. Dyskalemia has important prognostic implications. Hypokalemia is associated with excess morbidity and mortality in heart failure. The lower the K⁺ levels, the higher the risk, starting at K⁺ levels below approximately 4.0 mmol/l, with a steep risk increment with K⁺ levels <3.5 mmol/l. Hyperkalemia (>5.5 mmol/l) has also been associated with increased risk of adverse events; however, this association is prone to reverse-causation bias as stopping renin angiotensin aldosterone system inhibitor therapy in the advent of hyperkalemia likely contributes the observed risk. In this state-of-the-art review, practical and easy-to-implement strategies to deal with both hypokalemia and hyperkalemia are provided as well as guidance for the use of potassium-binders.

Hypertension and Electrolyte Disorders in Patients with COVID-19

The worldwide coronavirus disease 2019 (COVID-19) pandemic is still in progress, but much remains unknown about the disease. In this article, we review the association of hypertension or the renin-angiotensin system (RAS) with COVID-19 and the correlation between electrolyte disorders and disease severity. Underlying hypertension is likely to be associated with severe or critical COVID-19, but the relationship is not clear owing to confounding factors. Angiotensin-converting enzyme 2 (ACE2) plays an important role in the non-classical RAS pathway and binds to a receptor binding domain of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The RAS blockade is known to increase ACE2 levels, but controversy remains regarding the effect of RAS blockade therapy in the course of COVID-19. Some reports have indicated a protective effect of RAS blockade on COVID-19, whereas others have reported an association of RAS blockade therapy with the occurrence of severe complications such as acute kidney injury and admission to the intensive care unit. Electrolyte disorders are not uncommon in patients with COVID-19, and severe COVID-19 has frequently shown hypokalemia, hyponatremia, and hypocalcemia. Electrolyte imbalances are caused by alteration of RAS, gastrointestinal loss, effects of proinflammatory cytokines, and renal tubular dysfunction by the invasion of SARS-CoV-2.

Dyskalemia: a management problem for students

BACKGROUND

Although dyskalemia is common, its management can be problematic for students and general practitioners, especially when it occurs in patients with heart and renal failure. The basic academic knowledge of general medicine students, who have often not yet encountered clinical situations of dyskalemia, remains unclear in this regard.

OBJECTIVES

The purpose of this study was to evaluate the knowledge and reflexive practices of general medicine students in regard to dyskalemia.

METHODS

A cross-sectional survey, based on a self-questionnaire, of all of the students enrolled in general medicine studies at the Faculty of Medicine at the University of Nancy (France) at the end of their degree. The students were asked questions pertaining to specific clinical situations. The answers were compared to the information provided in the medical curriculum as well as to the relevant European guidelines.

RESULTS

We collected 290 of the questionnaires (participation rate: 81.2%). The hyper- and hypokalemia thresholds considered pathological (3.5-5.0 mmol/L) were known by 78% and 67% of the students, respectively. The perception of danger in case of severe hypokalemia was underestimated by 62.7% of them. In most cases, the proposed management of hyperkalemia in heart and renal failure did not comply with the relevant guidelines. The students tended to favor permanent discontinuation of the administration of converting enzyme inhibitors (ACE) and/or mineralocorticoid receptor antagonists (MRA) without considering the need for their reintroduction (51.6%). Sodium polystyrene sulfate was frequently seen as an appropriate first-line treatment for hyperkalemia (45%).

CONCLUSIONS

The knowledge and competence of general medicine students appear to be lacking for hyperkalemia in heart and renal failure, and they are long way from full compliance with the relevant European guidelines. Exposure to complex clinical situations as part of the medical curriculum, therefore, seems essential to improve the way dyskalemia is managed in France.

Preliminary evaluation of the efficacy of intravenous magnesium sulfate for the treatment of ventricular arrhythmias in 16 dogs

OBJECTIVE

To evaluate the efficacy of IV magnesium sulfate in decreasing the number of ventricular ectopic beats or convert ventricular tachyarrhythmia to sinus rhythm in dogs.

DESIGN

Prospective, observational feasibility study.

SETTING

Private referral center.

ANIMALS

Sixteen client-owned dogs exhibiting 1 or more of the following: (1) sustained or paroxysmal ventricular tachycardia (heart rate > 180/min), (2) single or multiform ventricular complexes at > 60 ectopies/min.

INTERVENTIONS

Pretreatment (T1) blood creatinine and electrolyte concentrations were measured. A 60-second lead II ECG strip and systolic arterial blood pressure (SABP) were recorded. Magnesium sulfate 0.1 mmol/kg (0.2 mEq/kg) was administered IV over 5 minutes. Five minutes after completion of the magnesium sulfate injection (T2), electrolyte concentrations were measured again. A second 60-second lead II ECG strip and SABP were recorded. The number of ectopic ventricular and supraventricular beats (sinus beats) that occurred in 60 seconds during the T1 and T2 ECG recordings was compared. T1 and T2 electrolytes and SABP were also compared.

RESULTS

There was an increase in the ionized magnesium concentration, a decrease in the heart rate and the number of ventricular ectopic beats, and an increase in the number of supraventricular beats at T2. Two dogs converted to a sinus rhythm at T2 that was not sustained.

CONCLUSIONS

Intravenous administration of 0.1 mmol/kg (0.2 mEq/kg) magnesium sulfate in dogs with ventricular ectopy decreased the number of ventricular beats and heart rate. However, a specific conclusion regarding the use of magnesium sulfate as a first-line therapy for dogs with ventricular tachyarrhythmias at the investigated dose cannot be made.

Genetics, prevalence, screening and confirmation of primary aldosteronism: a position statement and consensus of the Working Group on Endocrine Hypertension of The European Society of Hypertension

: Autonomous aldosterone overproduction represents the underlying condition of 5-10% of patients with arterial hypertension and carries a significant burden of mortality and morbidity. The diagnostic algorithm for primary aldosteronism is sequentially based on hormonal tests (screening and confirmation tests), followed by lateralization studies (adrenal CT scanning and adrenal venous sampling) to distinguish between unilateral and bilateral disease. Despite the recommendations of the Endocrine Society guideline, primary aldosteronism is largely underdiagnosed and undertreated with high between-centre heterogeneity. Experts from the European Society of Hypertension have critically reviewed the available literature and prepared a consensus document constituting two articles to summarize current knowledge on the epidemiology, diagnosis, treatment, and complications of primary aldosteronism.

Serum potassium in the PARADIGM-HF trial

Aims

The associations between potassium level and outcomes, the effect of sacubitril–valsartan on potassium level, and whether potassium level modified the effect of sacubitril–valsartan in patients with heart failure and a reduced ejection fraction were studied in PARADIGM‐HF. Several outcomes, including cardiovascular death, sudden death, pump failure death, non‐cardiovascular death and heart failure hospitalization, were examined.

Methods and results

A total of 8399 patients were randomized to either enalapril or sacubitril–valsartan. Potassium level at randomization and follow‐up was examined as a continuous and categorical variable (≤3.5, 3.6–4.0, 4.1–4.9, 5.0–5.4 and ≥5.5 mmol/L) in various statistical models. Hyperkalaemia was defined as K⁺ ≥5.5 mmol/L and hypokalaemia as K⁺ ≤3.5 mmol/L. Compared with potassium 4.1–4.9 mmol/L, both hypokalaemia [hazard ratio (HR) 2.40, 95% confidence interval (CI) 1.84–3.14] and hyperkalaemia (HR 1.42, 95% CI 1.10–1.83) were associated with a higher risk for cardiovascular death. However, potassium abnormalities were similarly associated with sudden death and pump failure death, as well as non‐cardiovascular death and heart failure hospitalization. Sacubitril–valsartan had no effect on potassium overall. The benefit of sacubitril–valsartan over enalapril was consistent across the range of baseline potassium levels.

Conclusions

Although both higher and lower potassium levels were independent predictors of cardiovascular death, potassium abnormalities may mainly be markers rather than mediators of risk for death.