Diuretic therapy for hypertension and the risk of primary cardiac arrest

Aqueous extract of Peristrophe bivalvis (L.) Merr. leaf reversed the detrimental effects of nitric oxide synthase inhibitor on blood lipid profile and glucose level

There is evidence that nitric oxide (NO) modulates the metabolism of glucose and lipid, and some antihypertensive medications have been shown to affect glucose and lipid metabolism. Peristrophe bivalvis is a medicinal plant that has been shown to have antihypertensive properties. The study investigated the effect of aqueous extract of Peristrophe bivalvis leaf (APB) on fasting blood glucose level (FBG) and lipid profile in rats pretreated with nitro-L-arginine methyl ester (L-NAME). Male Wistar rats (150-170 g, n=30) were randomly divided into two groups: control (CT, n=5) and L-NAME pretreated (n=25). CT received 5 mL/kg of distilled water [DW]) while L-NAME pretreated group received 60 mg/kg of L-NAME (L-NAME60) for eight weeks. After eight weeks, the L-NAME pretreated group was randomly subdivided into L-NAME group (LN), L-NAME recovery group (LRE), L-NAME ramipril group (LRA), and L-NAME APB group (LAPB). The groups received L-NAME60+DW, DW, L-NAME60+10 mg/kg ramipril, and L-NAME60+APB (200 mg/kg), respectively, for five weeks. Serum NO, lipid profile, cyclic guanosine monophosphate (cGMP), and insulin were measured by spectrophotometry, assay kits, and ELISA, respectively. Data were analysed using ANOVA at p < 0.05. At the eighth week, a fall in FBG and an increase in triglyceride, total cholesterol, and low-density lipoprotein cholesterol were recorded in L8 compared to CT. The same effects were also noticed in the thirteenth week in LN. However, FBG was significantly increased and lipid levels were decreased in LAPB compared to LN. A significant increase was observed in cGMP level in LAPB compared to LN. The study showed that APB corrected the hyperlipidemia and hypoglycemia caused by L-NAME, and this effect might be via the activation of cGMP.

Chlorthalidone vs Hydrochlorothiazide for Hypertension Treatment After Myocardial Infarction or Stroke: A Secondary Analysis of a Randomized Clinical Trial

Importance

Patients with prior myocardial infarction (MI) or stroke have a greater risk of recurrent cardiovascular (CV) events.

Objective

To evaluate the association of chlorthalidone (CTD) vs hydrochlorothiazide (HCTZ) with CV outcomes and noncancer deaths in participants with and without prior MI or stroke.

Design, Setting, and Participants

This was a prespecified secondary analysis of the Diuretic Comparison Project (DCP), a pragmatic randomized clinical trial conducted within 72 participating Veterans Affairs health care systems from June 2016 to June 2021, in which patients aged 65 years or older with hypertension taking HCTZ at baseline were randomized to continue HCTZ or switch to CTD at pharmacologically comparable doses. This secondary analysis was performed from January 3, 2023, to February 29, 2024.

Exposures

Pharmacologically comparable daily dose of HCTZ or CTD and history of MI or stroke.

Main Outcomes and Measures

Outcome ascertainment was performed from randomization to the end of the study. The primary outcome consisted of a composite of stroke, MI, urgent coronary revascularization because of unstable angina, acute heart failure hospitalization, or noncancer death. Additional outcomes included achieved blood pressure and hypokalemia (potassium level <3.1 mEq/L; to convert to mmol/L, multiply by 1.0).

Results

The DCP randomized 13 523 participants to CTD or HCTZ, with a mean (SD) study duration of 2.4 (1.4) years. At baseline, median age was 72 years (IQR, 69-75 years), and 96.8% were male. Treatment effect was evaluated in subgroups of participants with (n = 1455) and without (n = 12 068) prior MI or stroke at baseline. There was a significant adjusted interaction between treatment group and history of MI or stroke. Participants with prior MI or stroke randomized to CTD had a lower risk of the primary outcome than those receiving HCTZ (105 of 733 [14.3%] vs 140 of 722 [19.4%]; hazard ratio [HR], 0.73; 95% CI, 0.57-0.94; P = .01) compared with participants without prior MI or stroke, among whom incidence of the primary outcome was slightly higher in the CTD arm compared with the HCTZ arm (597 of 6023 [9.9%] vs 535 of 6045 [8.9%]; HR, 1.12; 95% CI, 1.00-1.26; P = .054) (P = .01 for interaction). The incidence of a nadir potassium level less than 3.1 mEq/L and hospitalization for hypokalemia differed among those with and without prior MI or stroke when comparing those randomized to CTD vs HCTZ, with a difference only among those without prior MI or stroke (potassium level <3.1 mEq/L: prior MI or stroke, 43 of 733 [5.9%] vs 37 of 722 [5.1%] [P = .57]; no prior MI or stroke, 292 of 6023 [4.9%] vs 206 of 6045 [3.4%] [P < .001]; hospitalization for hypokalemia: prior MI or stroke, 14 of 733 [1.9%] vs 16 of 722 [2.2%] [P = .72]; no prior MI or stroke: 84 of 6023 [1.4%] vs 57 of 6045 [0.9%] [P = .02]).

Conclusions and Relevance

Results of this secondary analysis of the DCP trial suggest that CTD may be associated with reduced major adverse CV events and noncancer deaths in patients with prior MI or stroke compared with HCTZ.

Trial Registration

ClinicalTrials.gov Identifier: NCT02185417.

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).

Thiazide diuretics alone or combined with potassium-sparing diuretics to treat hypertension: a systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

The magnitude of blood pressure (BP)-lowering effects and decrease of the adverse effects of thiazide diuretics provided by potassium-sparing diuretics remain uncertain. The aim of this study was to compare the BP-lowering efficacy and the incidence of adverse effects of high (T+) and low-dose (T-) thiazide diuretics, alone or combined with high (PS+) or low-dose (PS-) potassium-sparing diuretics in patients with primary hypertension.

METHODS

A systematic literature search was performed in PubMed/MEDLINE, the Cochrane Central Register of Controlled Trials, Embase, Web of Science, Scopus and LILACS. Randomized double-blind placebo or active-controlled trials (RCT) with 3 weeks to 1 year of follow-up were included. Sample size, mean and standard deviation from baseline, follow-up and change from baseline values were extracted by two independent reviewers. Pairwise random effect models and Bayesian network meta-analysis models were used to compare the effects of treatments. The risk of bias in individual studies was assessed using the Rob 1.0 tool. The primary outcome was the mean difference in office SBP. Secondary outcomes were the mean difference in biochemical parameters and the incidence of nonmelanoma skin cancer.

RESULTS

Two hundred and seventy-six double-blind RCTs involving 58 807 participants (mean age: 55 years; 45% women) were included. All treatment groups were more effective than placebo in lowering BP, with mean differences (MDs) of change from baseline ranging from -7.66 mmHg [95% credible interval (95% CrI), -8.53 to -6.79] for T- to -12.77 mmHg (95% CrI, -15.22 to -10.31) for T+PS-. T+ alone or combined with potassium-sparing was more effective in reducing BP than T-. The surface under the cumulative ranking curve (SUCRA) estimated ranking showed that the best effectiveness in lowering SBP was found for T+PS- (0.69), T+PS+ (0.65) and T+ (0.54). Compared with placebo, all treatments (except T-PS-) were associated with more potassium reduction and T+ compared with all other treatments and T- when compared with T-PS-. Compared with placebo, all active treatments (except T+PS+) showed higher elevations of uric acid. The increase of plasma glucose promoted by thiazides alone was reduced by potassium-sparing agents.

CONCLUSION

Thiazides with potassium-sparing diuretics are associated with increased BP-lowering efficacy compared with thiazides alone while minimizing hypokalaemia and hyperglycaemia. These findings demonstrate that thiazide and potassium-sparing diuretic combination is preferable to thiazide alone in treating hypertension.

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.

Thiazide diuretics alone or in combination with a potassium-sparing diuretic on blood pressure-lowering in patients with primary hypertension: protocol for a systematic review and network meta-analysis

BACKGROUND

The use of thiazide (T) diuretics for the treatment of hypertension may be associated with adverse metabolic effects, which can be minimized by combining thiazides with potassium-sparing (PS) diuretics. The additional blood pressure (BP)-lowering effect provided by the addition of a PS diuretic is unclear. Due to a large number of drugs in the T diuretics class, and the possible difference between them, there is a need to identify the best available evidence for health decision-making. This systematic review with network meta-analysis aims to compare the antihypertensive efficacy of T diuretics alone or in combination with a PS diuretic in patients with primary hypertension, as well as the safety of such drugs through the measurement of drug-related adverse events.

METHODS

A comprehensive electronic search will be conducted in six electronic bibliographic databases (PubMed/MEDLINE, Cochrane Library, Embase, Web of Science, Scopus, Lilacs), a registration database ( ClinicalTrials.gov ), and Educational Resources Information Center (ERIC [ProQuest]), published from inception to the date of the search. The search will be updated towards the end of the review. A hand search of the reference sections of the included studies and cited studies will also be performed. In case of missing data, authors will be contacted by e-mail or academic social networking sites whenever possible. To be included in the review, studies must be double-blind randomized controlled trials evaluating T diuretics alone or in combination with PS diuretics in patients with primary hypertension. The primary outcome measure will be office BP. Ambulatory BP monitoring (ABPM), non-melanoma skin cancer, major adverse cardiovascular events, laboratory parameters, and the number of withdrawals will be included as secondary outcomes. The results will be quantitatively summarized using differences between the mean change from baseline or differences between means for quantitative outcomes and relative risk for dichotomous outcomes. Results will be presented as mean or relative risk with credible intervals through a league table. The treatments will also be ranked using the surface under the cumulative ranking curve method. The risk of bias will be assessed through the RoB 1.0 tool.

DISCUSSION

To the best of our knowledge, this review will be the first to synthesize currently available evidence on the antihypertensive efficacy of different T diuretics alone or in combination with PS diuretics in adults with hypertension. The goals of hypertension treatment are to control high BP and to reduce associated cardiovascular morbidity and mortality, using the most appropriate therapy. Thiazides are widely used for pharmacological treatment due to their demonstrated effectiveness in reducing BP, favorable safety profile, and low cost. The results of this study will provide evidence regarding the best therapeutic strategies with T and PS diuretics, evidencing interventions with better antihypertensive efficacy and safety profile.

TRIAL REGISTRATION

This systematic review and network meta-analysis was prospectively registered at the PROSPERO database ( CRD42018118492 ).

A Carvedilol Analogue, VK-II-86, Prevents Hypokalaemia-induced Ventricular Arrhythmia through Novel multi-Channel Effects

BACKGROUND AND PURPOSE

QT prolongation and intracellular Ca²⁺ loading with diastolic Ca²⁺ release via ryanodine receptors (RyR2) are the predominant mechanisms underlying hypokalaemia-induced ventricular arrhythmia. We investigated the antiarrhythmic actions of two RyR2 inhibitors: dantrolene and VK-II-86, a carvedilol analogue with no β-blocking activity, in hypokalaemia.

EXPERIMENTAL APPROACH

Surface ECG and ventricular action potentials (APs) were recorded from whole-heart murine Langendorff preparations. Ventricular arrhythmia incidence was compared in hearts perfused with low [K⁺ ], and those pre-treated with dantrolene or VK-II-86. Whole-cell patch clamping was used in murine and canine ventricular cardiomyocytes to study the effects of dantrolene and VK-II-86 on AP parameters in low [K⁺ ] and the effects of VK-II-86 on the inward rectifier current (I_K1 ), late sodium current (I_{Na_L} ) and the L-type Ca²⁺ current (I_Ca ). Effects of VK-II-86 on I_Kr were investigated in transfected HEK-293 cells. A fluorogenic probe quantified the effects of VK-II-86 on oxidative stress in hypokalaemia.

KEY RESULTS

Dantrolene reduced the incidence of ventricular arrhythmias induced by low [K⁺ ] in explanted murine hearts by 94%, whereas VK-II-86 prevented all arrhythmias. VK-II-86 prevented hypokalaemia-induced AP prolongation and depolarization, but did not alter AP parameters in normokalaemia. Hypokalaemia was associated with a significant reduction of I_K1 and I_Kr , and increase in I_Na-L , and I_Ca . VK-II-86 prevented all hypokalaemia-induced changes in ion channel activity and oxidative stress.

CONCLUSIONS AND IMPLICATIONS

VK-II-86 prevents hypokalaemia-induced arrhythmogenesis by normalising calcium homeostasis and repolarization reserve. VK-II-86 may provide an exciting treatment in hypokalaemia and other arrhythmias caused by delayed repolarization or Ca²⁺ overload.

Comparison of Clinical Outcomes and Safety Associated With Chlorthalidone vs Hydrochlorothiazide in Older Adults With Varying Levels of Kidney Function

IMPORTANCE

Thiazide diuretics are commonly prescribed for the treatment of hypertension, a disease highly prevalent among older individuals and in those with chronic kidney disease. How specific thiazide diuretics compare in regard to safety and clinical outcomes in these populations remains unknown.

OBJECTIVE

To compare safety and clinical outcomes associated with chlorthalidone or hydrochlorothiazide use among older adults with varying levels of kidney function.

DESIGN, SETTING, AND PARTICIPANTS

This population-based retrospective cohort study was conducted in Ontario, Canada, from 2007 to 2015. Participants included adults aged 66 years or older who initiated chlorthalidone or hydrochlorothiazide during this period. Data were analyzed from December 2019 through September 2020.

EXPOSURES

New chlorthalidone users were matched 1:4 with new hydrochlorothiazide users by a high-dimensional propensity score. Time-to-event models accounting for competing risks examined the associations between chlorthalidone vs hydrochlorothiazide use and the outcomes of interest overall and within estimated glomerular filtration rate (eGFR) categories (≥60, 45-59, and <45 mL/min/1.73 m2).

MAIN OUTCOMES AND MEASURES

The outcomes of interest were adverse kidney events (ie, eGFR decline ≥30%, dialysis, or kidney transplantation), cardiovascular events (composite of myocardial infarction, coronary revascularization, heart failure, or atrial fibrillation), all-cause mortality, and electrolyte anomalies (ie, sodium or potassium levels outside reference ranges).

RESULTS

After propensity score matching, the study cohort included 12 722 adults (mean [SD] age, 74 [7] years; 7063 [56%] women; 5659 [44%] men; mean [SD] eGFR, 69 [19] mL/min/1.73 m2), including 2936 who received chlorthalidone and 9786 who received hydrochlorothiazide. Chlorthalidone use was associated with a higher risk of eGFR decline of 30% or greater (hazard ratio [HR], 1.24 [95% CI, 1.13-1.36]) and cardiovascular events (HR, 1.12 [95% CI, 1.04-1.22]) across all eGFR categories compared with hydrochlorothiazide use. Chlorthalidone use was also associated with a higher risk of hypokalemia compared with hydrochlorothiazide use, which was more pronounced among those with higher eGFR (eGFR ≥60 mL/min/1.73 m2: HR, 1.86 [95% CI, 1.67-2.08]; eGFR 45-59 mL/min/1.73 m2: HR, 1.57 [95% CI, 1.25-1.96]; eGFR <45 mL/min/1.73 m2: HR, 1.10 [95% CI, 0.84-1.45]; P for interaction = .001). No significant differences were observed between chlorthalidone and hydrochlorothiazide for dialysis or kidney transplantation (HR, 1.44 [95% CI, 0.88-2.36]), all-cause mortality (HR, 1.10 [95% CI, 0.93-1.29]), hyperkalemia (HR, 1.05 [95% CI, 0.79-1.39]), or hyponatremia (HR, 1.14 [95% CI, CI 0.98-1.32]).

CONCLUSIONS AND RELEVANCE

This cohort study found that among older adults, chlorthalidone use was associated with a higher risk of eGFR decline, cardiovascular events, and hypokalemia compared with hydrochlorothiazide use. The excess risk of hypokalemia with chlorthalidone was attenuated in participants with reduced kidney function. Placed in context with prior observational studies comparing the safety and clinical outcomes associated with thiazide diuretics, these results suggest that there is no evidence to prefer chlorthalidone over hydrochlorothiazide.

Race-Specific Comparisons of Antihypertensive and Metabolic Effects of Hydrochlorothiazide and Chlorthalidone

BACKGROUND

Chlorthalidone is recommended over hydrochlorothiazide (HCTZ) as the preferred thiazide, but the supporting evidence is not robust at routinely used doses, or in whites vs blacks, in whom differences in response to thiazides are well known. We compare the efficacy and safety of HCTZ and chlorthalidone as first-line therapies for white and black hypertensive patients.

METHODS

We compared treatment-related outcomes between the HCTZ arm (12.5 mg for 2-3 weeks; 25 mg for additional 6 weeks) of the Pharmacogenomic Evaluation of Antihypertensive Responses (PEAR, n = 376) and chlorthalidone arm (15 mg for 2 weeks; 25 mg for additional 6 weeks) of PEAR-2 (n = 326) clinical trials, in 17-65-year-old mild-moderate uncomplicated hypertensive whites and blacks.

RESULTS

Mean systolic/diastolic blood pressure (SBP/DBP) reduction with HCTZ vs chlorthalidone: 8 ± 8/4 ± 5 vs 12 ± 9/7 ± 5 mm Hg in whites (P < 10^-6 SBP and DBP); 12 ± 10/7 ± 6 vs 15 ± 10/9 ± 6 in blacks (P = .008 SBP, P = .054 DBP). Treatment with HCTZ vs chlorthalidone in whites resulted in significantly fewer patients achieving target BP (<140/90 mm Hg) (44% vs 57%, P = .018) and clinical response rate (≥10 mm Hg DBP reduction); and significantly higher nonresponse rate (<6 mm Hg DBP reduction); but no significant differences in rates among blacks (eg, target-BP rate: 56% vs 63%, P = .31). HCTZ treatment led to significantly lower rates of hypokalemia and hyperuricemia in whites and blacks, vs chlorthalidone, and significantly lower odds of requiring potassium supplementation among blacks (odds ratio 0.16; 95% confidence interval, 0.07-0.37; P = 3.4e^-7).

CONCLUSION

Compared with HCTZ, chlorthalidone showed greater blood pressure lowering and adverse metabolic effects in whites, but similar blood pressure lowering and greater adverse effects in blacks; suggesting that the recent guideline recommendations to choose chlorthalidone over HCTZ may not be warranted in blacks.

Certain beta blockers (e.g., bisoprolol) may be reevaluated in hypertension guidelines for patients with left ventricular hypertrophy to diminish the ventricular arrhythmic risk

Hypertensive left ventricular hypertrophy (HTN LVH) is associated with almost threefold increased risk of ventricular tachycardia (VT)/ventricular fibrillation (VF). Furthermore, HTN LVH increases the risk of sudden cardiac death (SCD). The reverse LV remodeling due to efficient antihypertensive therapy lowers the incidence rates of cardiovascular events and SCD and the vast majority of available arterial hypertension (HTN) guidelines recommend renin angiotensin system (RAS) blockers and calcium channel blockers (CCBs) for HTN LVH aiming for LVH regression. On the other hand, beta blockers (BBs) as a class are not recommended in HTN LVH due to their insufficient capacity to reverse LVH remodeling even though they are recommended as the first-line drugs for prevention/treatment of VT/VF (in general, unrelated to HTN LVH). Moreover, BBs are the best antiarrhythmic (against VT/VF) among antihypertensive drugs. Despite that, BBs are currently not recommended for LVH treatment in HTN Guidelines. It is important to prevent VT/VF in patients at high risk, such as those with HTN LVH. Therefore, certain BBs (such as Bisoprolol) may be reevaluated in guidelines for HTN (in the section of HTN LVH).

The Association Between Variability in Electrolytes and the In-Hospital Mortality in Critically Ill Children in Pediatric Intensive Care Units

Objective: This study aimed to explore the association between the variability in electrolytes and the in-hospital mortality in critically ill children admitted into intensive care units (ICUs). Design: This is a retrospective case-control study. Setting and Participants: Total of 11,245 children have been admitted to ICUs of Children's Hospital of Zhejiang University from 2010 to 2018. Methods: The coefficient of variation (CV), standard deviation (SD), and variability independent of the mean (VIM) were calculated as variability indices. High variability was defined as having values in the highest quartile for each parameter. Age, sex, diagnoses of disease, and surgical treatment were adjusted in the multivariable-adjusted logistic regression model. Results: A total of 11,245 children were included, and 660 patients died in the hospital. The median (P25, P75) potassium, sodium, and chloride of all patients were 3.8 (3.58, 4.09), 136.83 (135.11, 138.60), and 108.67 (105.71, 111.17), respectively. U-shaped relationships between the mean, lowest, and highest levels of potassium, sodium, and chloride and the in-hospital mortality were observed. The lowest mortality was noted when serum potassium, sodium, and chloride were between ~3.5 and 5.0, 135 and 145, and 105 and 115 mmol/l, respectively. The areas under the curve (AUCs) of three indices of variability in electrolytes were larger than those of the mean and lowest levels of electrolytes in predicting the in-hospital mortality. In the multivariable-adjusted model, the odds ratios and 95% confidence interval (CI) of the in-hospital mortality were 3.14 (2.44-4.04) for one parameter, 5.85 (4.54-7.53) for two parameters, and 10.32 (7.81-13.64) for three parameters compared with subjects having no parameters of high variability measured as the CV. The results were consistent when the variability was determined using the SD and VIM (all P for trend <0.001). Consistent results were noted in various subgroup analyses. Conclusions: This study showed that individuals with higher variability of each parameter were related with higher risk of in-hospital mortality. There was a linear association between the number of high variability parameters and the in-hospital mortality. The variability of electrolytes might be a good predictor for in-hospital mortality of children in ICUs.

Hydrochlorothiazide therapy: impact on early recurrence of atrial fibrillation after catheter ablation?

BACKGROUND

Hypokalemia has been linked to electrocardiogram changes and afterdepolarization-mediated arrhythmias. However, the association between hypokalemia and atrial fibrillation (AF) has not been well studied. Hydrochlorothiazide (HCT) diuretic therapy was shown to be associated with hypokalemia in multiple studies. We aimed to determine whether HCT therapy is associated with early recurrence of AF after radiofrequency (RF) catheter ablation during a 3-month follow-up.

METHODS

We performed a retrospective registry analysis of our internal AF ablation registry, containing 807 consecutive patients that underwent RF ablation for symptomatic AF. Propensity score matching was used to match 156 patients on HCT therapy with 156 controls. Furthermore, we performed propensity score matching between the first and the fourth quartile of baseline serum potassium (K) concentrations in the initial population (N.=807).

RESULTS

We observed a small but statistically significant difference in baseline mean potassium levels between the HCT group and the control group (4.03 mmol/L vs. 4.19 mmol/L respectively, P=0.001). There was no difference in short term recurrence of atrial fibrillation in the HCT group compared to the propensity score matched control group (41.0% [N.=64] vs. 45.5% [N.=71], P=0.424). In the comparison between the first and the fourth quartile of baseline serum potassium values, no difference in AF recurrence (38.2% [N.=63] vs. 37.0% [N.=61], P=0.820) during a 3-month follow-up after ablation was observed between both groups.

CONCLUSIONS

Patients on HCT therapy showed no difference in short term recurrence of AF after ablation compared to propensity matched controls.

Synthesis and biological evaluation of novel biphenyl-furocoumarin derivatives as vasodilator agents

A series of novel biphenyl-furocoumarin derivatives were synthesized based on the nuclear structure of imperatorin and identified by IR, ¹H NMR, ¹³C NMR and MS, and evaluated for their ability to relax vessel on isolated rat mesenteric artery, basilar artery and renal artery, respectively. The majority of compounds demonstrated potent vasodilatation, and compound 8e expressed the highest activity (EC₅₀ = 0.56 μM) in MA. Compounds with fluorine at 2-position of 5-phenyl get better activity than others with chlorine or bromine, and the compounds containing a bulky structure had relatively low activity, such as 8c (EC₅₀ = 22.39 μM) in MA. As a follow-up, 8e, 10e, and 8c were docked into L-calcium channel (PDB code: 3G43) to explain the difference in the activity of the compounds.

Antihypertensive therapy and sudden cardiac death, should we expect the unexpected?

Hypertension (HTN) and sudden cardiac death (SCD) constitute major public health problems accounting for millions of deaths each year worldwide. Both HTN and HTN-induced left ventricular hypertrophy (LVH) have been shown to be independent risk factors for SCD. However, the association between antihypertensive pharmacotherapy and risk of SCD has been under-investigated. Given that antihypertensive pharmacotherapy effectively reduces overall cardiovascular mortality, it would be expected to protect patients from SCD. Nevertheless, available data demonstrate that antihypertensive medications (primarily thiazide diuretics), while effective in reducing the incidence of myocardial infarction, do not confer protection from SCD. The purpose of this review was to present the relationship between HTN, LVH, and SCD and to describe the potential association between antihypertensive pharmacotherapy and risk of SCD.

Admission Serum Potassium Levels in Hospitalized Patients and One-Year Mortality

Background: The aim of this study was to assess the relationship between admission serum potassium and one-year mortality in all adult hospitalized patients. Methods: All adult hospitalized patients who had an admission serum potassium level between the years 2011 and 2013 at a tertiary referral hospital were enrolled. End-stage kidney disease patients were excluded. Admission serum potassium was categorized into levels of ≤2.9, 3.0–3.4, 3.5–3.9, 4.0–4.4, 4.5–4.9, 5.0–5.4, and ≥5.5 mEq/L. Cox proportional hazard analysis was performed to assess the independent association between admission serum potassium and one-year mortality after hospital admission, using an admission potassium level of 4.0–4.4 mEq/L as the reference group. Results: A total of 73,983 patients with mean admission potassium of 4.2 ± 0.5 mEq/L were studied. Of these, 12.6% died within a year after hospital admission, with the lowest one-year mortality associated with an admission serum potassium of 4.0–4.4 mEq/L. After adjustment for age, sex, race, estimated glomerular filtration rate (eGFR), principal diagnosis, comorbidities, medications, acute kidney injury, mechanical ventilation, and other electrolytes at hospital admission, both a low admission serum potassium ≤3.9 mEq/L and elevated admission potassium ≥5.0 mEq/L were significantly associated with an increased risk of one-year mortality, when compared with an admission serum potassium of 4.0–4.4 mEq/L. Subgroup analysis of chronic kidney disease and cardiovascular disease patients showed similar results. Conclusion: This study demonstrated that hypokalemia ≤3.9 mEq/L and hyperkalemia ≥5.0 mEq/L at the time of hospital admission were associated with higher one-year mortality.

Österreichischer Blutdruckkonsens 2019

Erhöhter Blutdruck bleibt eine Hauptursache von kardiovaskulären Erkrankungen, Behinderung und frühzeitiger Sterblichkeit in Österreich, wobei die Raten an Diagnose, Behandlung und Kontrolle auch in rezenten Studien suboptimal sind. Das Management von Bluthochdruck ist eine häufige Herausforderung für Ärztinnen und Ärzte vieler Fachrichtungen. In einem Versuch, diagnostische und therapeutische Strategien zu standardisieren und letztendlich die Rate an gut kontrollierten Hypertoniker/innen zu erhöhen und dadurch kardiovaskuläre Erkrankungen zu verhindern, haben 13 österreichische medizinische Fachgesellschaften die vorhandene Evidenz zur Prävention, Diagnose, Abklärung, Therapie und Konsequenzen erhöhten Blutdrucks gesichtet. Das hier vorgestellte Ergebnis ist der erste Österreichische Blutdruckkonsens. Die Autoren und die beteiligten Fachgesellschaften sind davon überzeugt, daß es einer gemeinsamen nationalen Anstrengung bedarf, die Blutdruck-assoziierte Morbidität und Mortalität in unserem Land zu verringern.

Antipsychotic drugs and sudden cardiac death: A literature review of the challenges in the prediction, management, and future steps

Sudden cardiac death (SCD) is relatively uncommon, yet it is a deadly consequence of some antipsychotic medications in patients with psychiatric disorders. The widespread concerns about the adverse cardiac effects associated with antipsychotics and their unpredictable nature have led to a restriction on the use of some antipsychotic medications. Recent progress has been made in the identification of important genetic factors that may contribute to the adverse complication of antipsychotic drugs, suggesting that high-risk individuals can be identified prior to initiating therapy. In addition, some high-tech smart wearable medical devices have recently been developed, allowing users to record and analyze the electrocardiogram (ECG) in couple with artificial intelligence (AI) technologies, and notifying of irregular heart rhythms or arrhythmias, a medical condition well documented in most SCD cases. In this literature review, we summarize recent advances in understanding the link between SCD and antipsychotic drug usage, as well as in utilizing wearable medical devices for monitoring of cardiac arrhythmias. New strategies for improving the care of patients receiving antipsychotic medications are proposed. As it is now possible to evaluate the risk of SCD in patients on antipsychotic medications, preventative measures and close monitoring may be used to detect the early signs of adverse cardiac events and SCD.

Impact of Hormone Therapy on Laboratory Values in Transgender Patients

BACKGROUND

For transgender individuals taking hormone therapy (HT), data on laboratory values are limited, and the effects on laboratory values cannot be easily predicted. We evaluated the impact on common laboratory analytes in transgender individuals before and after initiation of HT.

METHODS

We conducted a retrospective chart review of transgender patients identified at transgender-specific clinics at an urban county hospital and community clinic. Laboratory data were collected on hormone concentrations, hematologic parameters, electrolytes, lipids, and liver and renal markers before and after initiation of HT.

RESULTS

We identified 183 transgender women (TW) and 119 transgender men (TM) for whom laboratory data were available. In all, 87 TW and 62 TM had baseline laboratory data, and data were also available for 133 TW and 89 TM on HT for &gt;6 months. The most significant changes were seen in red blood cell count, hemoglobin concentration, hematocrit, and creatinine levels after &gt;6 months of HT, which increased in TM and decreased in TW after HT (P &lt; 0.005; d index &gt; 0.6). Alkaline phosphatase, aspartate aminotransferase, and alanine aminotransferase levels increased in TM; however, the effect size was small (d index &lt; 0.5). Calcium, albumin, and alkaline phosphatase levels significantly decreased in TW (P &lt; 0.001; d &gt; 0.6). Additionally, TM were found to have increased triglycerides and decreased HDL levels (P &lt; 0.005; d &gt; 0.6).

CONCLUSIONS

Changes occur in several common laboratory parameters for patients on HT. Some laboratory values changed to match the gender identity, whereas others remained unchanged or were intermediate from the baseline values. These findings will help guide interpretation of laboratory test results in transgender patients taking HT.

Risk factor paradox: No prognostic impact of arterial hypertension and smoking in patients with ventricular tachyarrhythmias

BACKGROUND

Data regarding the outcome of patients with ventricular tachyarrhythmias related to arterial hypertension (AHT) and smoking is limited. The study sought to assess the prognostic impact of AHT and smoking on survival in patients presenting with ventricular tachyarrhythmias.

METHODS

All consecutive patients surviving ventricular tachycardia (VT) and ventricular fibrillation (VF) upon admission to the University Medical Center Mannheim (UMM), Germany from 2002 to 2016 were included and stratified according to AHT and smoking by propensity score matching. The primary prognostic endpoint was all-cause mortality at 30 months.

RESULTS

A total of 988 AHT-matched patients (494 each, with and without AHT) and a total of 872 smoking-matched patients (436 each, with and without smoking) were included. The rates of VT and VF were similar in both groups (VT: AHT 60% vs. no AHT 60%; smokers 61% vs. non-smokers 62%; VF: AHT 35% vs. no AHT 38%; smokers 39% vs. non-smokers 38%). Neither AHT nor smoking were associated with the primary endpoint of long-term all-cause mortality at 30 months (long-term mortality rates: AHT/no AHT, 26% vs. 28%; log-rank p = 0.525; smoking/non-smoking, 22% vs. 25%; log-rank p = 0.683).

CONCLUSIONS

Paradoxically, neither AHT nor smoking were associated with differences of long-term all-cause mortality in patients presenting with ventricular tachyarrhythmias.

Antipsychotics and cardiovascular risk: A case/non-case study

Severe mental disorders have been reported to be associated with an increased cardiovascular risk. To measure the potential risk excess as compared, not with the baseline cardiovascular risk for the general population, but with the cardiovascular risk associated with drug iatrogenia. 197 reported cases of cardiovascular adverse reaction to antipsychotic drugs as compared to the reported cases of this type of adverse reactions to drugs other than antipsychotics entered in the Spanish Pharmacovigilance System database (FEDRA) (1995-2018) in an observational case/non-case study. Risk estimates of association were reporting odds ratio (ROR), and, chi-square test (χ²). Overall disproportionality for the whole drug class was found [ROR 2.3 (95% CI 2.0-2.7)], χ² = 127.07]. When the two types of antipsychotics (typical and atypical) were analysed separately, we also found statistically significant disproportionality, and this disproportionality is similar between both groups, with disproportionality measures around 2.30, with the confidence intervals not including the 1. The disproportionality observed suggests a risk excess that might be greater than expected, which holds particularly true for torsade de pointes, sudden death and cardiac arrhythmias in patients treated with any of the two types of antipsychotics. There was no significant risk for ischaemic heart disease.

Hypokalemia-Induced Arrhythmias and Heart Failure: New Insights and Implications for Therapy

Routine use of diuretics and neurohumoral activation make hypokalemia (serum K⁺ < 3. 5 mM) a prevalent electrolyte disorder among heart failure patients, contributing to the increased risk of ventricular arrhythmias and sudden cardiac death in heart failure. Recent experimental studies have suggested that hypokalemia-induced arrhythmias are initiated by the reduced activity of the Na⁺/K⁺-ATPase (NKA), subsequently leading to Ca²⁺ overload, Ca²⁺/Calmodulin-dependent kinase II (CaMKII) activation, and development of afterdepolarizations. In this article, we review the current mechanistic evidence of hypokalemia-induced triggered arrhythmias and discuss how molecular changes in heart failure might lower the threshold for these arrhythmias. Finally, we discuss how recent insights into hypokalemia-induced arrhythmias could have potential implications for future antiarrhythmic treatment strategies.

Hypertension and cardiac arrhythmias: a consensus document from the European Heart Rhythm Association (EHRA) and ESC Council on Hypertension, endorsed by the Heart Rhythm Society (HRS), Asia-Pacific Heart Rhythm Society (APHRS) and Sociedad Latinoamericana de Estimulación Cardíaca y Electrofisiología (SOLEACE)

Hypertension is a common cardiovascular risk factor leading to heart failure (HF), coronary artery disease, stroke, peripheral artery disease and chronic renal insufficiency. Hypertensive heart disease can manifest as many cardiac arrhythmias, most commonly being atrial fibrillation (AF). Both supraventricular and ventricular arrhythmias may occur in hypertensive patients, especially in those with left ventricular hypertrophy (LVH) or HF. Also, some of the antihypertensive drugs commonly used to reduce blood pressure, such as thiazide diuretics, may result in electrolyte abnormalities (e.g. hypokalaemia, hypomagnesemia), further contributing to arrhythmias, whereas effective control of blood pressure may prevent the development of the arrhythmias such as AF. In recognizing this close relationship between hypertension and arrhythmias, the European Heart Rhythm Association (EHRA) and the European Society of Cardiology (ESC) Council on Hypertension convened a Task Force, with representation from the Heart Rhythm Society (HRS), Asia-Pacific Heart Rhythm Society (APHRS), and Sociedad Latinoamericana de Estimulación Cardíaca y Electrofisiología (SOLEACE), with the remit to comprehensively review the available evidence to publish a joint consensus document on hypertension and cardiac arrhythmias, and to provide up-to-date consensus recommendations for use in clinical practice. The ultimate judgment regarding care of a particular patient must be made by the healthcare provider and the patient in light of all of the circumstances presented by that patient.

Pharmacogenomics study of thiazide diuretics and QT interval in multi-ethnic populations: the cohorts for heart and aging research in genomic epidemiology

Thiazide diuretics, commonly used antihypertensives, may cause QT interval (QT) prolongation, a risk factor for highly fatal and difficult to predict ventricular arrhythmias. We examined whether common single-nucleotide polymorphisms (SNPs) modified the association between thiazide use and QT or its component parts (QRS interval, JT interval) by performing ancestry-specific, trans-ethnic and cross-phenotype genome-wide analyses of European (66%), African American (15%) and Hispanic (19%) populations (N=78 199), leveraging longitudinal data, incorporating corrected standard errors to account for underestimation of interaction estimate variances and evaluating evidence for pathway enrichment. Although no loci achieved genome-wide significance (P<5 × 10-8), we found suggestive evidence (P<5 × 10-6) for SNPs modifying the thiazide-QT association at 22 loci, including ion transport loci (for example, NELL1, KCNQ3). The biologic plausibility of our suggestive results and simulations demonstrating modest power to detect interaction effects at genome-wide significant levels indicate that larger studies and innovative statistical methods are warranted in future efforts evaluating thiazide-SNP interactions.

Evidence of Drug-Nutrient Interactions with Chronic Use of Commonly Prescribed Medications: An Update

The long-term use of prescription and over-the-counter drugs can induce subclinical and clinically relevant micronutrient deficiencies, which may develop gradually over months or even years. Given the large number of medications currently available, the number of research studies examining potential drug-nutrient interactions is quite limited. A comprehensive, updated review of the potential drug-nutrient interactions with chronic use of the most often prescribed medications for commonly diagnosed conditions among the general U.S. adult population is presented. For the majority of the interactions described in this paper, more high-quality intervention trials are needed to better understand their clinical importance and potential consequences. A number of these studies have identified potential risk factors that may make certain populations more susceptible, but guidelines on how to best manage and/or prevent drug-induced nutrient inadequacies are lacking. Although widespread supplementation is not currently recommended, it is important to ensure at-risk patients reach their recommended intakes for vitamins and minerals. In conjunction with an overall healthy diet, appropriate dietary supplementation may be a practical and efficacious way to maintain or improve micronutrient status in patients at risk of deficiencies, such as those taking medications known to compromise nutritional status. The summary evidence presented in this review will help inform future research efforts and, ultimately, guide recommendations for patient care.

The impact of serum potassium-influencing antihypertensive drugs on the risk of out-of-hospital cardiac arrest: A case-control study

AIMS

Sudden cardiac arrest (SCA) is a complex multifactorial event and most commonly caused by ventricular tachycardia/ fibrillation (VT/ VF). Some antihypertensive drugs could induce hypokalaemia or hyperkalaemia, which may increase susceptibility to VT/VF and SCA.

OBJECTIVE

To assess the association between different classes of antihypertensive drugs classified according to their potential impact on serum potassium levels and the occurrence of out-of-hospital cardiac arrest (OHCA) based on VT/VF.

METHODS

A case-control study was performed among current users of antihypertensive drugs. Cases were OHCA victims with electrocardiogram documented VT/VF drawn from the AmsteRdam REsuscitation STudies (ARREST) registry, and controls were non-OHCA individuals from the PHARMO database. Antihypertensive drugs were classified into: (i) antihypertensives with neutral effect on serum potassium levels; (ii) hypokalaemia-inducing antihypertensives; (iii) hyperkalaemia-inducing antihypertensives; (iv) combination of antihypertensives with hypo- and hyperkalaemic effects.

RESULTS

We included 1345 cases and 4145 controls. The risk of OHCA was significantly increased among users of hypokalaemia-inducing antihypertensives [adjusted odds ratio (OR) 1.39; 95% confidence interval (CI) 1.10-1.76] and among users of a combination of antihypertensives with hypo- and hyperkalaemic effects (adjusted OR 1.42; 95%CI 1.17-1.72) vs. users of antihypertensives with neutral effect. There was no difference in OHCA risk between users of hyperkalaemia-inducing antihypertensives vs. users of antihypertensive drugs with neutral effect (adjusted OR 1.15; 95%CI 0.95-1.40).

CONCLUSION

The risk of OHCA is significantly increased in patients who were current users of hypokalaemia-inducing antihypertensives and patients using a combination of antihypertensives with hypo- and hyperkalaemic effects.

Role of abnormal repolarization in the mechanism of cardiac arrhythmia

In cardiac patients, life-threatening tachyarrhythmia is often precipitated by abnormal changes in ventricular repolarization and refractoriness. Repolarization abnormalities typically evolve as a consequence of impaired function of outward K⁺ currents in cardiac myocytes, which may be caused by genetic defects or result from various acquired pathophysiological conditions, including electrical remodelling in cardiac disease, ion channel modulation by clinically used pharmacological agents, and systemic electrolyte disorders seen in heart failure, such as hypokalaemia. Cardiac electrical instability attributed to abnormal repolarization relies on the complex interplay between a provocative arrhythmic trigger and vulnerable arrhythmic substrate, with a central role played by the excessive prolongation of ventricular action potential duration, impaired intracellular Ca²⁺ handling, and slowed impulse conduction. This review outlines the electrical activity of ventricular myocytes in normal conditions and cardiac disease, describes classical electrophysiological mechanisms of cardiac arrhythmia, and provides an update on repolarization-related surrogates currently used to assess arrhythmic propensity, including spatial dispersion of repolarization, activation-repolarization coupling, electrical restitution, TRIaD (triangulation, reverse use dependence, instability, and dispersion), and the electromechanical window. This is followed by a discussion of the mechanisms that account for the dependence of arrhythmic vulnerability on the location of the ventricular pacing site. Finally, the review clarifies the electrophysiological basis for cardiac arrhythmia produced by hypokalaemia, and gives insight into the clinical importance and pathophysiology of drug-induced arrhythmia, with particular focus on class Ia (quinidine, procainamide) and Ic (flecainide) Na⁺ channel blockers, and class III antiarrhythmic agents that block the delayed rectifier K⁺ channel (dofetilide).

Increased afterload following myocardial infarction promotes conduction-dependent arrhythmias that are unmasked by hypokalemia

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Although the pathophysiological significance of hypertension in post-MI patients is established, mechanisms by which increased afterload alters the electrophysiological substrate and promotes arrhythmias after MI is unknown.

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We developed a new porcine model of MI/iAL that exhibits widespread interstitial fibrosis, increased profibrotic gene expression, and propensity to pacing-induced arrhythmias when challenged with hypokalemia.

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Investigation of the electrophysiological substrate revealed the dependence of these arrhythmias on hypokalemia-mediated conduction and not repolarization abnormalities.

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A steep negative slope of rate-dependent conduction slowing in MI/iAL is consistent with a high safety factor for propagation of slow wavefronts before onset of sustained ventricular tachycardia/ventricular fibrillation.

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Fibrosis in MI/iAL promotes the successful propagation of critically slow wavefronts leading to re-entrant arrhythmias that are unmasked by hypokalemia.

Although the pathophysiological significance of resistant hypertension in post–myocardial infarction (MI) patients is established, the mechanisms by which increased afterload in that setting worsens outcome are unclear. With regard to sudden cardiac death, whether increased afterload alters the electrophysiological substrate after MI is unknown. We established a new large animal model of chronic post-MI remodeling with increased afterload that exhibits widespread deposition of fibrosis in remote areas from the anterior MI, mimicking the disease phenotype of patients with advanced ischemic heart disease. We identified the mode of initiation and mechanism of arrhythmias that were consistently unmasked by hypokalemia in this clinically relevant model.

Maintenance of negative fluid balance can improve endothelial and cardiac functions in primary hypertensive patients

PURPOSE

The issue of unidentified volume expansion is well recognized as a cause for resistance to antihypertensive therapy. The aim of study is to identify contribution of negative fluid balance to hypertension control and impact on endothelial and cardiac functions among primary hypertensive patients who do not have kidney failure.

MATERIALS AND METHODS

This is a prospective interventional study with one-year follow-up. Preceded by volume status measurements were performed by a body composition monitor (BCM), the patients were put on ambulatory blood pressure monitoring for 24 hours. Then, echocardiographic assessments and flow-mediated dilation (FMD) and carotid intima-media thickness (CIMT) measurements were completed. Patients in one of the two groups were kept negative hydrated during trial with diuretic treatment.

RESULTS

At the end of one-year follow-up, patients in negative hydrated group were found to have significantly lower CIMT, left ventricle mass index, left ventricular end-diastolic diameter, mean systolic and diastolic BP, non-dipper patient ratio, and higher FMD. In negatively hydrated group, target organ damage significantly reduced during trial.

CONCLUSIONS

The significance of negative hydration status with respect to blood pressure control, endothelial and cardiac functions within primary hypertensive patients who do not suffer from kidney failure has been demonstrated.

Large-scale detection of drug off-targets: hypotheses for drug repurposing and understanding side-effects

Background

Promiscuity in molecular interactions between small-molecules, including drugs, and proteins is widespread. Such unintended interactions can be exploited to suggest drug repurposing possibilities as well as to identify potential molecular mechanisms responsible for observed side-effects.

Methods

We perform a large-scale analysis to detect binding-site molecular interaction field similarities between the binding-sites of the primary target of 400 drugs against a dataset of 14082 cavities within 7895 different proteins representing a non-redundant dataset of all proteins with known structure. Statistically-significant cases with high levels of similarities represent potential cases where the drugs that bind the original target may in principle bind the suggested off-target. Such cases are further analysed with docking simulations to verify if indeed the drug could, in principle, bind the off-target. Diverse sources of data are integrated to associated potential cross-reactivity targets with side-effects.

Results

We observe that promiscuous binding-sites tend to display higher levels of hydrophobic and aromatic similarities. Focusing on the most statistically significant similarities (Z-score ≥ 3.0) and corroborating docking results (RMSD < 2.0 Å), we find 2923 cases involving 140 unique drugs and 1216 unique potential cross-reactivity protein targets. We highlight a few cases with a potential for drug repurposing (acetazolamide as a chorismate pyruvate lyase inhibitor, raloxifene as a bacterial quorum sensing inhibitor) as well as to explain the side-effects of zanamivir and captopril. A web-interface permits to explore the detected similarities for each of the 400 binding-sites of the primary drug targets and visualise them for the most statistically significant cases.

Conclusions

The detection of molecular interaction field similarities provide the opportunity to suggest drug repurposing opportunities as well as to identify potential molecular mechanisms responsible for side-effects. All methods utilized are freely available and can be readily applied to new query binding-sites. All data is freely available and represents an invaluable source to identify further candidates for repurposing and suggest potential mechanisms responsible for side-effects.

Electronic supplementary material

The online version of this article (doi:10.1186/s40360-017-0128-7) contains supplementary material, which is available to authorized users.

Effects of Long-Acting Loop Diuretics in Heart Failure With Reduced Ejection Fraction Patients With Cardiac Resynchronization Therapy

There have been no reports evaluating the impact of long-acting loop diuretics (LLD) on the outcome of heart failure (HF) and arrhythmia treatment in HF with reduced ejection fraction (HFrEF) patients implanted with a cardiac resynchronization therapy (CRT) device.This was a prospective, single-blind, randomized crossover study. We allocated 21 consecutive CRT implanted patients into 2 groups. The furosemide group received furosemide as a first treatment and azosemide as a second treatment. The azosemide group received this treatment in the reverse order. The first treatment was given to each group for 6 months and the second treatment continued for an additional 6 months. We combined the data of each medication regimen in each group and analyzed it at baseline, 6 months, and 1 year. The primary endpoints were the variation of fluid index and thoracic impedance measured by CRT at 6 months.The baseline characteristics were similar for both groups. The difference in the primary endpoints was not statistically significant between the 2 medication arms (fluid index: -29.6 ± 64.4 versus 16.2 ± 48.2; P = 0.22, thoracic impedance: -0.49 ± 17.8 versus 2.45 ± 12.5; P = 0.56). Likewise, the clinical outcome of HF and the CRT derived parameters in both arms were comparable.HFrEF patients taking LLD after CRT implantation might be comparable to those taking short-acting loop diuretics in the treatment of HF and HF-associated arrhythmias.

Preoperative serum potassium predicts the clinical outcome after non-cardiac surgery

BACKGROUND

Potassium disorders have been linked to adverse outcomes in various medical conditions. However, the association of preoperative serum potassium with postoperative outcome is not well established. We aimed to examine the association between preoperative potassium with a 30-day mortality and adverse cardiovascular event (MACE).

METHODS

We conducted a cohort study using a prospectively collected database of patients, undergoing surgical procedures from 1998 to 2013 in the VA Western New York Healthcare System, which are reported to the Veterans Affairs Surgical Quality Improvement Program (VASQIP). The patients were categorized into three groups based on their documented preoperative potassium concentrations. Hypokalemia was defined as serum potassium concentration <4 mmol/L and hyperkalemia was defined as serum potassium concentrations >5.5 mmol/L. The values within the range of 4.0-5.5 mmol/L were considered as normokalemia and used as the control group. Statistical analyses included Chi-square test, analysis of variance and multivariate logistic regression to estimate the risk of MACE within 30 days of surgery.

RESULTS

Study included 5959 veterans who underwent surgery between 1998 and 2013. The patients in the hyperkalemics group had lower kidney function compared to the other two groups. The frequency of MACE was 13.6% in hypokalemics and 21.9% in hyperkalemics that were both significantly higher than 4.9% in controls. In multivariate logistic regression the hazard risk (HR) ratios of MACE were (2.17, 95% CI 1.75-2.70) for hypokalemics and (3.23, 95% CI 2.10-4.95) for hyperkalemics when compared to normokalemic controls.

CONCLUSIONS

Preoperative hypokalemia and hyperkalemia are both independent predictors of MACE within 30 days.

Hypokalemia in women and methadone therapy are the strongest non-cardiologic factors associated with QT prolongation in an emergency department setting

BACKGROUND

Our primary objective was to determine the adjusted quantitative associations of clinical predictors with QT prolongation, a defining cause of Torsades de Pointes (TdP).

METHODS

A retrospective cohort study was performed on consecutive emergency department patients identified by ECG acquisition date, and heart rate corrected QT (QTc) and QRS durations. QTc was modeled as a function of clinical predictors with multiple linear regression.

RESULTS

1010 patients were included. The strongest predictors of QTc and their coefficients were: antidysrhythmic (26.1ms, 95% CI 15.6-36.6) and methadone (43.6ms, 95% CI 28.1-59.2) therapies, and genetic long QT syndrome diagnosis (32.6ms, 95% CI -4.7-70.0). The association of QTc with serum potassium was approximated by a two piecewise linear function that differed by sex. For potassium below 3.9mmol/L, QTc increased by 43.0ms (95% CI 26.2-59.7) and 29.5ms (95% CI 19.1-40.0) for every 1mmol/L decrease in potassium in women and men, respectively. TdP occurred in only 4/686 (0.6%) of patients with QTc≥500 and QRS<120, but mortality during the visit including hospitalization was 8.0%.

CONCLUSIONS

QTc duration is highly sensitive to hypokalemia, particularly in women. Methadone prolongs QTc remarkably compared to other non-cardiologic medicines. QTc>500 with normal QRS often signifies profound illness and substantial mortality risk, though not necessarily imminent TdP.

High-Dose Citalopram and Escitalopram and the Risk of Out-of-Hospital Death

OBJECTIVE

Studies demonstrating that higher doses of citalopram (> 40 mg) and escitalopram (> 20 mg) prolong the corrected QT interval prompted regulatory agency warnings, which are controversial, given the absence of confirmatory clinical outcome studies. We compared the risk of potential arrhythmia-related deaths for high doses of these selective serotonin reuptake inhibitors (SSRIs) to that for equivalent doses of fluoxetine, paroxetine, and sertraline.

METHODS

The Tennessee Medicaid retrospective cohort study included 54,220 persons 30-74 years of age without cancer or other life-threatening illness who were prescribed high-dose SSRIs from 1998 through 2011. The mean age was 47 years, and 76% were female. Demographic characteristics and comorbidity for individual SSRIs were comparable. Because arrhythmia-related deaths are typically sudden and occur outside the hospital, we analyzed out-of-hospital sudden unexpected death as well as sudden cardiac deaths, a more specific indicator of proarrhythmic effects.

RESULTS

The adjusted risk of sudden unexpected death for citalopram did not differ significantly from that for the other SSRIs. The respective hazard ratios (HRs) for citalopram versus escitalopram, fluoxetine, paroxetine, and sertraline were 0.84 (95% CI, 0.40-1.75), 1.24 (95% CI, 0.75-2.05), 0.75 (95% CI, 0.45-1.24), and 1.53 (95% CI, 0.91-2.55). There were no significant differences for sudden cardiac death or all study deaths, nor were there significant differences among high-risk patients (≥ 60 years of age, upper quartile baseline cardiovascular risk). Escitalopram users had no significantly increased risk for any study end point.

CONCLUSIONS

We found no evidence that risk of sudden unexpected death, sudden cardiac death, or total mortality for high-dose citalopram and escitalopram differed significantly from that for comparable doses of fluoxetine, paroxetine, and sertraline.

Long-term prognosis associated with early repolarisation pattern in Chinese population with atherosclerotic risk factors

BACKGROUND

Recent evidence has linked early repolarisation pattern (ERP) to sudden cardiac death (SCD) in patients without structural heart disease. However, no studies have clarified the prognostic value of ERP in people at high risk for atherosclerotic heart disease.

METHODS

We prospectively assessed the prognostic significance of ERP on ECGs in a community-based population of 18 231 subjects with atherosclerotic risk factors (49.3% men, mean age 64.0 years). Mean follow-up was 7.6 years. Cox models were used to estimate the hazard ratios (HRs) adjusted for possible confounding factors.

RESULTS

Compared with those without ERP, subjects with ERP had a significantly increased risk of developing SCD (HR 1.91, 95% CI 1.30 to 2.82), death from coronary heart disease (CHD) (HR 1.80, 95% CI 1.45 to 2.22) and death from any cause (HR 1.35, 95% CI 1.22 to 1.50). ERP was not associated with an increased risk of non-sudden CHD death and non-CHD death. ERP with J wave pattern in inferior leads, high amplitude of J wave pattern, notching configuration and horizontal or descending ST segment indicated a higher risk for SCD. ERP was associated with an absolute risk increase of 52.3 additional SCDs per 100 000 person-years in the population at high risk for atherosclerotic heart disease.

CONCLUSIONS

ERP is associated with a significantly increased risk for SCD, CHD death and death from any cause in people with atherosclerotic risk factors. The observed association between ERP and all-cause mortality appears to be driven by an association with CHD death, in particular SCD.

Diuretics in the treatment of hypertension

Diuretics have long been used for the treatment of hypertension. Thiazide diuretics are the most commonly prescribed diuretics for hypertension, but other classes of diuretics may be useful in alternative circumstances. Although diuretics are no longer considered the preferred agent for treatment of hypertension in adults and children, they remain acceptable first-line options. Diuretics effectively decrease blood pressure in hypertensive patients, and in adults with hypertension reduce the risk of adverse cardiovascular outcomes. Because of varied pharmacokinetic and pharmacodynamic differences, chlorthalidone may be the preferred thiazide diuretic in the treatment of primary hypertension. Other types of diuretics (e.g., loop, potassium sparing) may be useful for the treatment of hypertension related to chronic kidney disease (CKD) and other varied conditions. Common side effects of thiazides are mostly dose-related and involve electrolyte and metabolic abnormalities.

Serum potassium levels, cardiac arrhythmias, and mortality following non-ST-elevation myocardial infarction or unstable angina: insights from MERLIN-TIMI 36

BACKGROUND

In acute coronary syndrome (ACS), potassium levels <3.5 mEq/L are associated with ventricular arrhythmias. Current guidelines therefore recommend a potassium target >4.0 mEq/L in ACS. Our study evaluated the association between potassium levels, cardiac arrhythmias, and cardiovascular death in patients with non-ST-segment elevation myocardial infarction or unstable angina.

METHODS

Potassium levels were measured in 6515 patients prior to randomization to receive either ranolazine or a placebo in the MERLIN-TIMI 36 trial. A seven-day continuous electrocardiographic assessment was obtained to determine the incidence of non-sustained ventricular tachycardia (NSVT) and ventricular pauses. The association between potassium levels and cardiovascular death was evaluated using a Cox proportional hazards regression model with multivariable adjustment.

RESULTS

NSVT lasting for at least eight consecutive beats occurred more frequently at potassium levels <3.5 mEq/L than at potassium levels ⩾5 mEq/L (10.1 vs. 4.5%, p=0.03 for trend), whereas the inverse pattern was observed for ventricular pauses >3 s, which occurred more frequently at potassium levels ⩾5 mEq/L than at potassium levels <3.5 mEq/L (5.9 vs. 2.0%, p=0.03 for trend). There was a U-shaped relationship between the potassium level at admission and both early and late risk of cardiovascular death. Compared with patients with potassium levels of 3.5 to <4 mEq/L, a potassium level <3.5 mEq/L was associated with an increased risk of cardiovascular death at day 14 (2.4 vs. 0.8%, HR_adj 3.1, p=0.02) and at one year (6.4 vs. 3.0%, HR_adj 2.2, p=0.01). The risk of cardiovascular death at one year was also significantly increased at potassium levels ⩾4.5 mEq/L and a similar trend was noted at potassium levels ⩾5 mEq/L.

CONCLUSIONS

The lowest risk of cardiovascular death was observed in patients with admission potassium levels between 3.5 and 4.5 mEq/L. Both lower and higher levels of potassium were associated with tachyarrhythmias and bradyarrhythmias, suggesting a potential mechanistic explanation for the increased risk of cardiovascular death at the extremes of potassium homeostasis.

Diuretics in primary hypertension - Reloaded

Diuretics have long been cherished as drugs of choice for uncomplicated primary hypertension. Robust mortality and morbidity data is available for diuretics to back this strategy. Off-late the interest for diuretics has waned off perhaps due to availability of more effective drugs but more likely due to perceived lack of tolerance and side-effect profile of high-dose of diuretics required for mortality benefit. Low-dose diuretics particularly thiazide diuretics are safer but lack the mortality benefit shown by high-dose. However, indapamide and low dose chlorthalidone have fewer side-effects but continue to provide mortality benefit.

PDA-Based Documentation of Medication Interventions in an Ambulatory Care Setting

Background:

Although personal digital assistant (PDA)-based documentation systems are available for documentation of clinical pharmacy services, none is specific to documentation of drug-related problems (DRPs) in the ambulatory care setting.

Objective:

To describe types of medication interventions performed by pharmacists in an urban ambulatory care clinic within a teaching hospital, determine predictors of preselected DRPs, and describe physician acceptance rates.

Methods:

Following development of a PDA-based documentation system, this 6 month prospective study documented interventions performed by a clinical pharmacy team. Descriptive statistics were employed to describe the type and frequency of interventions and physician acceptance rates. Multivariate logistic regression analysis was used to determine significant predictors for preselected DRPs.

Results:

Over a 6 month period, 965 interventions were documented. The patients' mean ± SD age was 61.8 ± 15.51 years, 72.3% of patients were female, and the mean number of medications was 7.1 ± 3.95 per intervention. The most common interventions were laboratory monitoring (56.2%), patient education (14.5%), and changes in drug therapy (12.4%). The use of antihypertensive agents was a predictor for the DRPs “dose too high” and “dose too low” (p = 0.001 and p = 0.003, respectively). Of the applicable interventions, 89.8% (246/274) were accepted by the physician.

Conclusions:

Pharmacists in this urban ambulatory care clinic offered a variety of recommendations that were well received by physicians.

Evaluation of STAT medication ordering process in a community hospital

Background:

In most health care facilities, problems related to delays in STAT medication order processing time are of common concern.

Objective:

The purpose of this study was to evaluate processing time for STAT orders at Kimball Medical Center.

Methods:

All STAT orders were reviewed to determine processing time; order processing time was also stratified by physician order entry (physician entered (PE) orders vs. non-physician entered (NPE) orders). Collected data included medication ordered, indication, time ordered, time verified by pharmacist, time sent from pharmacy, and time charted as given to the patient.

Results:

A total of 502 STAT orders were reviewed and 389 orders were included for analysis. Overall, median time was 29 minutes, IQR 16–63; p<0.0001.). The time needed to process NPE orders was significantly less than that needed for PE orders (median 27 vs. 34 minutes; p=0.026). In terms of NPE orders, the median total time required to process STAT orders for medications available in the Automated Dispensing Devices (ADM) was within 30 minutes, while that required to process orders for medications not available in the ADM was significantly greater than 30 minutes. For PE orders, the median total time required to process orders for medications available in the ADM (i.e., not requiring pharmacy involvement) was significantly greater than 30 minutes. [Median time = 34 minutes (p<0.001)].

Conclusion:

We conclude that STAT order processing time may be improved by increasing the availability of medications in ADM, and pharmacy involvement in the verification process.

Clinical Utility of Potassium-Sparing Diuretics to Maintain Normal Serum Potassium in Peritoneal Dialysis Patients

♦ BACKGROUND: Hypokalemia is a vexing problem in end-stage renal disease patients on peritoneal dialysis (PD), and oral potassium supplements (OPS) have limited palatability. Potassium-sparing diuretics (KSD) (spironolactone, amiloride) may be effective in these patients. ♦ METHODS: We performed a cross-sectional review of 75 current or past (vintage > 6 months) PD patients with regard to serum potassium (K+), OPS, and KSD utilization. We reviewed charts for multiple clinical and laboratory variables, including dialysis adequacy, residual renal function, nutritional status and co-existing medical therapy. ♦ RESULTS: The cohort was middle-aged with a mean age of 49.2 years (standard deviation [SD] = 14.7) and overweight with a body mass index of 29.5 (6.7) kg/m². Of all the participants, 57.3% were female, 73.3% African-American, and 48% diabetic with an overall PD vintage of 28.2 (24.3) months at the time of enrollment. Weekly Kt/V was 2.12 (0.43), creatinine clearance was 73.5 (33.6) L/week/1.73 m² with total daily exchange volume of 10.8 (2.7) L. Residual urine output (RUO) measured at 440 (494) mL (anuric 30.6%). Three-month averaged serum K⁺ measured at 4 (0.5) mmol/L with 36% of the participants receiving K⁺ supplements (median: 20 [0;20] mmol/day) and 41.3% KSD (spironolactone dose: 25 - 200 mg/day; amiloride dose: 5 - 10 mg/day). Serum K⁺ correlated positively with weekly Kt/V (r = 0.239; p = 0.039), PD vintage (r = 0.272; p = 0.018) but not with PD modality, daily exchange volume, RUO, or KSD use. However, KSD use was associated with decreased use of OPS (r = -0.646; p < 0.0001). ♦ CONCLUSIONS: Potassium-sparing diuretics were effective in this cohort of PD patients and decreased the need for OPS utilization.

Ventricular tachyarrhythmia and sudden cardiac death with domperidone use in Parkinson's disease

AIM

Domperidone is preferentially used over other antiemetic agents to treat digestive symptoms in Parkinson's disease (PD). Concerns have been raised regarding an increased risk of ventricular tachyarrhythmia and sudden cardiac death (VT/SCD) associated with domperidone in the general population. However, the risk in PD is unknown.

METHODS

We conducted a multicentre retrospective cohort study using administrative databases from seven Canadian provinces and the UK Clinical Practice Research Datalink. Using a nested case-control analysis, we estimated the rate ratios (RRs) of VT/SCD associated with domperidone use compared to no use in patients newly-diagnosed with PD. VT/SCD events were identified using administrative medical records and vital statistics with a manual review of all potential cases. Meta-analytic methods were used to estimate overall effects across sites.

RESULTS

Among 214 962 patients with PD, 2907 cases of VT/SCD were identified during 886 581 person-years of follow-up (incidence rate 3.28 per 1000 persons per year). Current use of domperidone was associated with a non-statistically significant 22% increased risk of VT/SCD (RR 1.22; 95% CI 0.99-1.50) compared with no use. The risk was significantly elevated in those with a history of cardiovascular disease (RR 1.38; 95% CI 1.07-1.78), but not in those without (RR 1.21; 95% CI 0.81-1.81). Dose and duration of use did not affect the magnitude of the risk.

CONCLUSION

Domperidone use may increase the risk of VT/SCD in patients with PD, particularly those with a history of cardiovascular disease. This risk may be underestimated because of imprecision in identifying VT/SCD events.

Approach to Antihypertensive Therapy

Antihypertensive agents are commonly prescribed by physicians to prevent the long-term mortality from chronic hypertension. They are also given to improve survival in a number of conditions (eg, heart failure, coronary artery disease), independent of the effect on blood pressure. Several classes of antihypertensives are available with unique pharmacologic characteristics and adverse effects. Not all agents in the same class have identical effects, and careful selection of drugs based on the comorbid conditions is recommended.

Electrolyte and acid-base abnormalities associated with purging behaviors

OBJECTIVE

Eating disorders that are associated with purging behaviors are complicated by frequent blood electrolyte and acid-base abnormalities. Herein, we review the major electrolyte and acid-base abnormalities and their treatment methods. The body of rigorous, eating disorder-specific literature on this topical area is not robust enough to perform a systematic review as defined by PRISMA guidelines. Therefore, a qualitative review of mostly medical literature was conducted.

RESULTS

Hypokalemia, hyponatremia, and sodium chloride-responsive metabolic alkalosis are the most common serum changes that occur as a result of purging behaviors. They vary depending on the mode and frequency of purging behaviors. They can all potentially cause dangerous medical complications and are in need of definitive medical treatment.

DISCUSSION

Eating disorders that are associated with purging behaviors are associated with a number of electrolyte and acid-base changes which are complex in their origin, documented to be medically dangerous and this definitive treatment is necessary to help achieve a successful treatment outcome, and in need of definitive treatment as described herein.

Not just chlorthalidone: evidence-based, single tablet, diuretic alternatives to hydrochlorothiazide for hypertension

Accounting for 15 % of deaths worldwide, hypertension is often treated with hydrochlorothiazide (HCTZ) (50 million prescriptions annually). HCTZ has a <24-h duration of action, is less potent than chlorthalidone and all major antihypertensive drug classes, and is inferior to four antihypertensive drugs for cardiovascular event (CVE) reduction. If there were alternative diuretics, why prescribe HCTZ? Chlorthalidone is often offered as an alternative to HCTZ, but has limited pharmaceutical formulations. However, there are seven evidence-based, single-tablet, alternative diuretics. For reducing CVE, the following are superior to their comparators: chlorthalidone versus four antihypertensives in multiple hypertensive populations; indapamide versus placebo in elderly Chinese (and versus enalapril for left ventricular hypertrophy), triamterene-HCTZ versus placebo in elderly Europeans, amiloride-HCTZ versus three antihypertensives, and indapamide-perindopril versus placebo in three populations. Additionally, chlorthalidone-azilsartan and spironolactone-HCTZ are potent combinations The aldosterone antagonist component of the latter combination has been shown to reduce total mortality by 30 % in heart failure. Five of these seven have multiple dose formulations. Six cost $4-$77 monthly. In conclusion, based on both scientific and practical grounds, new prescriptions for HCTZ are rarely justified.

Molecular Basis of Hypokalemia-Induced Ventricular Fibrillation

BACKGROUND

Hypokalemia is known to promote ventricular arrhythmias, especially in combination with class III antiarrhythmic drugs like dofetilide. Here, we evaluated the underlying molecular mechanisms.

METHODS AND RESULTS

Arrhythmias were recorded in isolated rabbit and rat hearts or patch-clamped ventricular myocytes exposed to hypokalemia (1.0-3.5 mmol/L) in the absence or presence of dofetilide (1 μmol/L). Spontaneous early afterdepolarizations (EADs) and ventricular tachycardia/fibrillation occurred in 50% of hearts at 2.7 mmol/L [K] in the absence of dofetilide and 3.3 mmol/L [K] in its presence. Pretreatment with the Ca-calmodulin kinase II (CaMKII) inhibitor KN-93, but not its inactive analogue KN-92, abolished EADs and hypokalemia-induced ventricular tachycardia/fibrillation, as did the selective late Na current (INa) blocker GS-967. In intact hearts, moderate hypokalemia (2.7 mmol/L) significantly increased tissue CaMKII activity. Computer modeling revealed that EAD generation by hypokalemia (with or without dofetilide) required Na-K pump inhibition to induce intracellular Na and Ca overload with consequent CaMKII activation enhancing late INa and the L-type Ca current. K current suppression by hypokalemia and dofetilide alone in the absence of CaMKII activation were ineffective at causing EADs.

CONCLUSIONS

We conclude that Na-K pump inhibition by even moderate hypokalemia plays a critical role in promoting EAD-mediated arrhythmias by inducing a positive feedback cycle activating CaMKII and enhancing late INa. Class III antiarrhythmic drugs like dofetilide sensitize the heart to this positive feedback loop.

Misconceptions and facts about treating hypertension

Hypertension is a powerful risk factor strongly linked to adverse cardiovascular outcomes. Because of its high prevalence, health care providers at many levels are involved in treating hypertension. Distinct progress has been made in improving the rates of hypertension awareness and treatment over years, but the overall control of hypertension remains inadequate. Several recent guidelines from different sources have been put forward in an attempt to bridge the gap between existing evidence and clinical practice. Despite this effort, several misconceptions about treating hypertensive cardiovascular disease continue to persist among clinicians. This review highlights some of the misconceptions regarding antihypertensive therapy.