Optimization of pharmacotherapy in chronic heart failure: is heart rate adequately addressed?

Heart rate control and its predictors in patients with heart failure and sinus rhythm. Data from the European Society of Cardiology Long-Term Registry

BACKGROUND

Higher resting heart rate (HR) in patients with heart failure (HF) and sinus rhythm (SR) is associated with increased mortality. In patients hospitalized for HF, the aim herein, was to assess the use and dosage of guideline-recommended HR lowering medications, HR control at discharge and predictors of HR control.

METHODS

In the present study, were Polish participants of the European Society of Cardiology HF Long-Term (ESC-HF-LT) Registry. Those selected were hospitalized for HF, with reduced ejection fraction (HFrEF) and SR at discharge (n = 236). The patients were divided in two groups ( < 70 and ≥ 70 bpm). Logistic regression was used to identify the predictors of HR ≥ 70 bpm.

RESULTS

Of patients with HFrEF and SR, 59% had HR ≥ 70 bpm at hospital discharge. At discharge, 96% and only 0.5% of the patients with HFrEF and SR received beta-blocker and ivabradine, respectively. In the HF groups < 70 and ≥ 70 bpm, only 11% and 4% of patients received beta-blocker target doses, respectively. There was no difference in the use of other guideline-recommended medications. Age, New York Heart Association class, HR on admission and lack of HR lowering medications were predictors of discharge HR ≥ 70 bpm.

CONCLUSIONS

Heart rate control after hospitalization for HFrEF is unsatisfactory, which may be attributed to suboptimal doses of beta-blockers, and negligence in use other HR lowering drugs (including ivabradine).

Resting heart rate in ambulatory heart failure with reduced ejection fraction treated with beta-blockers

AIMS

Current guidelines recommend beta-blocker therapy in chronic heart failure with reduced ejection fraction (HFrEF) titrated according to tolerated target dose. The efficiency of this strategy to obtain adequate heart rate (HR) control remains unclear in clinical practice. The aim of this study was to determine, in a real-world setting, the proportion of HFrEF patients who fail to achieve beta-blocker target doses, whether target doses of beta-blockers have a relationship with the adequacy in reducing resting HR over time.

METHODS AND RESULTS

Beta-blocker dose and resting HR of consecutive ambulatory patients with a diagnosis of HFrEF (ejection fraction ≤ 35%) in sinus rhythm were reviewed at the first outpatient contact in the Cleveland Clinic Health System from the year 2000 to 2015. Patients who did not receive beta-blocker therapy, have congenital heart disease and hypertrophic cardiomyopathy, were not in sinus rhythm, or have a history of heart transplant were excluded. Patients were followed up until their last known visit at the Cleveland Clinic. Median resting HR was 71 b.p.m. [inter-quartile range (IQR) 60-84 b.p.m.] in 8041 patients (median age 65; 68% male) with 67% on carvedilol, 32% on metoprolol succinate, and 1% on bisoprolol. In 3674 subjects (56%), resting HR was ≥70 b.p.m. At final follow-up after a median of 21 months (IQR 0.1-7.2 years), resting HR was 72 b.p.m. (IQR 60-84 b.p.m.) in the subset of patients with persistently low ejection fraction ≤ 35%. HR ≥ 70 b.p.m. was observed in 55% of this group. Beta-blocker target dose was achieved in 19%, 5%, and 15% of those receiving carvedilol, metoprolol succinate, and bisoprolol, respectively. In the subset of patients who experienced beta-blocker up-titration, reduced mortality or hospitalization due to heart failure was observed in patients who experienced the lowest HR after titration.

CONCLUSIONS

In our single-centre experience, the majority of patients with chronic HFrEF treated with beta-blocker therapy did not achieve target doses over time, and a substantial proportion had inadequate control of resting HR. There was no relationship between achieved beta-blocker target dose and resting HR control.

Treatment optimization of beta-blockers in chronic heart failure therapy

Although evidence based guidelines recommend optimal use of beta blockers in all patients with chronic heart failure unless contraindicated, they are often underutilized and/or prescribed below the recommended dosage in the majority of patients with heart failure. To our knowledge, however, the optimal use of beta-blockers in chronic heart failure is not investigated in Ethiopia. Therefore, the aim of our study was to investigate the utilization and optimization of beta blockers in the management of patients with chronic heart failure in Ethiopia. A prospective observational study was conducted among ambulatory patients with chronic heart failure in Ethiopia. We included adult patients with a diagnosis of heart failure with a baseline left ventricular ejection fraction < 40% who had been on follow-up for at least 6 months. Patients were recruited into the study during their appointment for medication refilling using simple random sampling technique. All patients were followed for at least 6 months to determine the optimal use of beta blockers. The optimal use of beta blockers was determined according to evidence based guidelines. After explaining the purpose of the study, we obtained written informed consent from all participants. Data were collected through patient interview and review of patients' medical records. Binary logistic regression analysis was performed to identify factors associated with utilization of beta blockers. A total of 288 patients were included in the study. Out of the total, 67% of the patients were receiving beta blockers. Among the patients who received beta blockers, 34.2% were taking guideline recommended beta blockers while 65.8% were taking atenolol, which is not guideline recommended beta blocker. Among the patients who received guideline recommended beta blockers, only 3% were taking optimal dose. Prior hospitalization [Adjusted Odds ratio (AOR) 0.38, 95% confidence interval (CI) 0.19-0.76], dose of furosemide > 40 mg (AOR 0.39, 95% CI 0.20-0.76), ischemic heart disease (AOR 3.27, 95% CI 1.66-6.45), atrial fibrillation (AOR 4.41, 95% CI 1.38-14.13) were significantly associated with the utilization of beta-blockers. Despite proven benefit, beta blockers were not optimally used in most of the participants in this study. The presence of ischemic heart disease and atrial fibrillation were positively associated with the utilization of beta blockers while hospitalization and higher diuretic dose were negatively associated with the utilization of beta blockers. Clinicians should attempt to use evidence based beta blockers at guideline recommended target doses that have been shown to have morbidity and mortality benefit in chronic heart failure. Moreover, more effort needs to be done to minimize the potentially modifiable risk factors for underutilization of beta blocker in chronic heart failure therapy.

Advances in the management of heart failure: the role of ivabradine

A high resting heart rate (≥70–75 b.p.m.) is a risk factor for patients with heart failure (HF) with reduced ejection fraction (EF), probably in the sense of accelerated atherosclerosis, with an increased morbidity and mortality. Beta-blockers not only reduce heart rate but also have negative inotropic and blood pressure-lowering effects, and therefore, in many patients, they cannot be given in the recommended dose. Ivabradine specifically inhibits the pacemaker current (funny current, I_f) of the sinoatrial node cells, resulting in therapeutic heart rate lowering without any negative inotropic and blood pressure-lowering effect. According to the European Society of Cardiology guidelines, ivabradine should be considered to reduce the risk of HF hospitalization and cardiovascular death in symptomatic patients with a reduced left ventricular EF ≤35% and sinus rhythm ≥70 b.p.m. despite treatment with an evidence-based dose of beta-blocker or a dose below the recommended dose (recommendation class “IIa” = weight of evidence/opinion is in favor of usefulness/efficacy: “should be considered”; level of evidence “B” = data derived from a single randomized clinical trial or large nonrandomized studies). Using a heart rate cutoff of ≥ 75 b.p.m., as licensed by the European Medicines Agency, treatment with ivabradine 5–7.5 mg b.i.d. reduces cardiovascular mortality by 17%, HF mortality by 39% and HF hospitalization rate by 30%. A high resting heart rate is not only a risk factor in HF with reduced EF but also at least a risk marker in HF with preserved EF, in acute HF and also in special forms of HF. In this review, we discuss the proven role of ivabradine in the validated indication “HF with reduced EF” together with interesting preliminary findings, and the potential role of ivabradine in further, specific forms of HF.

Relation of Elevated Heart Rate in Patients With Heart Failure With Reduced Ejection Fraction to One-Year Outcomes and Costs

There are limited data describing outcomes associated with an elevated heart rate in patients with heart failure with reduced ejection fraction (HFrEF) in routine clinical practice. We identified patients with HFrEF at Duke University Hospital undergoing echocardiograms and heart rate assessments without paced rhythms or atrial fibrillation. Outcomes (all-cause mortality or hospitalization and medical costs per day alive) were assessed using electronic medical records, hospital cost accounting data, and national death records. Patients were stratified by heart rate (<70 and ≥70 beats/min) and compared using generalized linear models specified with gamma error distributions and log links for costs and proportional hazard models for mortality/hospitalization. Of 722 eligible patients, 582 patients (81%) were treated with β blockers. The median heart rate was 81 beats/min (25th and 75th percentiles 69 to 96) and 527 patients (73%) had a heart rate ≥70 beats/min. After multivariate adjustment, a heart rate ≥70 beats/min was associated with increased 1-year all-cause mortality or hospitalization, hazard ratio 1.37 (95% CI 1.07 to 1.75) and increased medical costs per day alive, cost ratio 2.03 (95% CI 1.53 to 2.69). In conclusion, at a large tertiary care center, despite broad use of β blockers, a heart rate ≥70 beats/min was observed in 73% of patients with HFrEF and associated with worse 1-year outcomes and increased direct medical costs per day alive.

Ivabradine in Management of Heart Failure: a Critical Appraisal

Elevated resting heart rate has been linked to poor outcomes in patients with chronic systolic heart failure. Blockade of funny current channel with ivabradine reduces heart rate without inotropic effects. Ivabradine was recently approved by US Food and Drug Administration for patients with stable, symptomatic chronic heart failure (HF) with left ventricular ejection fraction (LVEF) ≤35 %, who are in sinus rhythm with resting heart rate (HR) ≥ 70 bpm and either are on maximally tolerated doses of beta-blockers, or have a contraindication to beta-blockers. This article will review and evaluate the data supporting the use of ivabradine in patients with HF and explore its mechanisms and physiologic effects.

The Role of Ivabradine and Trimetazidine in the New ESC HF Guidelines

The prevalence of heart failure (HF) is increasing, representing a major cause of death and disability, and a growing financial burden on healthcare systems. Despite the use of effective treatments with both drugs and devices, mortality remains high. There is therefore a need for new and effective therapeutic agents. Ivabradine is a specific sinus node inhibiting agent that was approved in 2005 by the European Medicines Agency, alone or in combination with a beta-blocker. Trimetazidine is a cytoprotective, anti-ischaemic agent established in the treatment of angina pectoris. In the 2012 European Society of Cardiology (ESC) guidelines for diagnosis and treatment of HF, ivabradine was recommended in symptomatic HF patients who are in sinus rhythm with left ventricular ejection fraction ≤35 % and heart rate higher than 70 beats per minute, despite optimal medical therapy, including maximally tolerated dose of beta-blocker. The role of trimetazidine in this setting was not mentioned. In the 2016 ESC guidelines, recommendations for ivabradine are unchanged but trimetazidine is included for the treatment of angina pectoris with HF. This article discusses the need for new therapeutic options in HF and reviews clinical evidence in support of these two therapeutic options.

[Update on therapy of chronic heart failure. Innovations and studies from last year]

Chronic heart failure is one of the most common chronic diseases worldwide with increasing prevalence and incidence. Due to the high morbidity and mortality a standardized and evidence-based therapy is crucial. The present review article gives an overview about the innovations in 2014 based on the current guidelines of the European Society of Cardiology. First, improvements in established medication regimens regarding beta blockers and mineralocorticoid receptor antagonists as well as treatment options for heart rate reduction will be explained. Second, new pharmacological developments, such as angiotensin receptor neprilysin inhibition will be discussed. Finally, new insights into common comorbidities of patients with chronic heart failure, such as atrial fibrillation and hyperkalemia will be presented.

Low systolic blood pressure and high resting heart rate as predictors of outcome in patients with peripartum cardiomyopathy

BACKGROUND

Patients with peripartum cardiomyopathy (PPCM) present with low blood pressure (SBP) often preventing uptitration of heart failure medication. We aimed to study prediction of risk and the contribution of high resting heart rate (HR) and low SBP to risk in recent onset of PPCM.

METHODS

Clinical assessment with HR and SBP, echocardiography and laboratory results were obtained at baseline and at six months on 206 patients with recent onset PPCM enrolled at two tertiary care centers in South Africa. Poor outcome was defined as the combined endpoint of death, LVEF<35% or remaining in New York Heart Association (NYHA) functional class III/IV at six months. Complete LV recovery was defined as LVEF ≥ 55% at six months.

RESULTS

Poor outcome was observed in 110 of 220 patients (53%), with 26 patients dying at six months (12.6%). There were 98 (47.5%) patients with SBP ≤ 110 mmHg. Patients with high HR (HR ≥ 100) and low SBP (< 110 mmHg) tended to have worse outcomes than patients below the HR median and high SBP. PPCM patients with low SBP and high HR were less likely to be on ACE-inhibitors (n = 35, 69% versus n = 129, 84%, p = 0.024) and on the beta blocker carvedilol (n = 24, 47% versus n = 98, 64%, p = 0.047). Low SBP, high HR and left ventricular end diastolic diameter at baseline were predictors of poor outcome. Patients with low SBP and high HR had the highest mortality (p = 0.0023).

CONCLUSIONS

These findings suggest increased risk in patients with PPCM presenting with low SBP and high HR on standard heart failure medication possibly having implications on HF management.

Resting heart rate: risk indicator and emerging risk factor in cardiovascular disease

Resting heart rate is central to cardiac output and is influenced by changes occurring in numerous diseases. It predicts longevity and cardiovascular diseases, and current evidence suggests that it is also an important marker of outcome in cardiovascular disease, including heart failure. Beta-blockers improve outcomes in heart failure; however, they have effects outside reducing heart rate. Ivabradine has demonstrated efficacy in reducing rehospitalizations and mortality in heart failure and in improving exercise tolerance and reducing angina attacks in patients with coronary artery disease, whereas selective heart rate reduction may also prove to be beneficial in therapeutic areas outside those in which ivabradine has already demonstrated clinical efficacy. This review provides an update on the associations between heart rate and cardiovascular outcomes in various conditions, the experimental effects of heart rate reduction with ivabradine, and the potential new indications in cardiovascular disease.

Addition of ivabradine to β-blocker improves exercise capacity in systolic heart failure patients in a prospective, open-label study

INTRODUCTION

Difficulties initiating and uptitrating β-blockers due to tolerability can complicate management of heart failure. Among other actions, β-blockers reduce heart rate, which is an important cardiovascular risk factor in heart failure. A new therapeutic strategy is ivabradine, which reduces resting heart rate and is associated with improved outcomes.

METHODS

A 5-month, prospective, open-label, nonrandomized single-center study was performed in 69 patients. All patients had chronic heart failure with left ventricular systolic dysfunction in sinus rhythm, each were initiated on 3.125 mg twice daily (bid) carvedilol alone (n = 36) or 3.125 mg bid carvedilol/5 mg bid ivabradine (n = 33), on top of background therapy including angiotensin-converting enzyme inhibitor (88%), diuretics (86%), antiplatelet agents (91%), and statins (90%). Dosages were uptitrated every 2 weeks to 25 mg bid carvedilol in both groups and 7.5 mg bid ivabradine maximum in the carvedilol/ivabradine group. Uptitration of carvedilol lasted 1.9 ± 0.4 months with carvedilol/ivabradine and 2.8 ± 0.6 months with carvedilol alone (P < 0.05).

RESULTS

The patients receiving ivabradine had lower resting heart rate at 5 months (61.6 ± 3.1 versus 70.2 ± 4.4 bpm, P < 0.05). Adding ivabradine to carvedilol in patients with heart failure was associated with increases in the 6-min walk test and ejection fraction (all P < 0.05). Treatment tolerability was satisfactory. Patients receiving ivabradine and carvedilol had lower heart rates and better exercise capacity than those on carvedilol alone.

CONCLUSION

Adding ivabradine to carvedilol in patients with chronic heart failure improves the uptitration of β-blocker. The results merit further verification in a prospective double-blind study.

Novel and nonpharmacologic approaches to cardio-protection in hypertension

Hypertension has wide (30-45 %) prevalence in the general population and is related to important increases in overall cardiovascular morbidity and mortality. Despite lifestyle modifications and optimal medical therapy (three drugs, one being diuretic), about 5-20 % of hypertensives are affected by resistant hypertension. Chronic high blood pressure has adverse effects on the heart and other organs such as the kidneys and vasculature. Renal sympathetic denervation and baroreceptor stimulation are invasive approaches initially investigated to treat resistant hypertension. Their pleiotropic effects appear promising in cardiovascular remodeling, heart failure and arrhythmias and could potentially affect cardiovascular morbidity and mortality.

Ivabradine treatment in a chronic heart failure patient cohort: symptom reduction and improvement in quality of life in clinical practice

Introduction

In the prospective, open-label multicenter INTENSIFY study, the effectiveness and tolerability of ivabradine as well as its impact on quality of life (QOL) in chronic systolic heart failure (CHF) patients were evaluated over a 4-month period.

Methods

In CHF patients with an indication for treatment with ivabradine, resting heart rate (HR), heart failure symptoms [New York Heart Association (NYHA) class, signs of decompensation], left ventricular ejection fraction, brain natriuretic peptide (BNP) values, QOL, and concomitant medication with focus on beta-blocker therapy were documented at baseline, after 4 weeks, and after 4 months. The results were analyzed using descriptive statistical methods.

Results

Thousand nine hundred and fifty-six patients with CHF were included. Their mean age was 67 ± 11.7 years and 56.9% were male. 77.8% were receiving beta-blockers. Other concomitant medications included angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (83%), diuretics (61%), aldosterone antagonists (18%), and cardiac glycosides (8%). At baseline, the mean HR of patients was 85 ± 11.8 bpm, 51.1% and 37.2% of patients were classified as NYHA II and III, respectively, and 22.7% showed signs of decompensation. BNP concentrations were tracked in a subgroup, and values exceeding 400 pg/mL were noted in 53.9% of patients. The mean value of the European quality of life-5 dimensions (EQ-5D) QOL index was 0.64 ± 0.28. After 4 months of treatment with ivabradine, HR was reduced to 67 ± 8.9 bpm. Furthermore, the proportion of patients presenting with signs of decompensation decreased to 5.4% and the proportion of patients with BNP levels >400 pg/mL dropped to 26.7%, accompanied by a shift in NYHA classification towards lower grading (24.0% and 60.5% in NYHA I and II, respectively). EQ-5D index improved to 0.79 ± 0.21.

Conclusion

Over 4 months of treatment, ivabradine effectively reduced HR and symptoms in CHF patients in this study reflecting daily clinical practice. These benefits were accompanied by improved QOL and good general tolerability.

Electronic supplementary material

The online version of this article (doi:10.1007/s12325-014-0147-3) contains supplementary material, which is available to authorized users.

Comparison of clinical profile and management of outpatients with heart failure with reduced left ventricular ejection fraction treated by general practitioners and cardiologists in contemporary Poland: the results from the DATA-HELP registry

OBJECTIVE

We sought to determine and compare clinical profile and management of outpatients with heart failure with reduced ejection fraction (HFREF) treated by cardiologists and general practitioners (GPs) in Poland.

METHODS

All the 790 randomly selected cardiologists and GPs in the DATA-HELP registry, which included 5563 patients, filled out questionnaires about 10 consecutive outpatients with HFREF.

RESULTS

Outpatients managed by GPs were older (69±10 vs 66±12 years), and the prevalence of men was less marked (58% vs 67%). They also had higher left ventricular ejection fraction (38±6% vs 35±8%) and had more pulmonary congestion (63% vs 49%) and peripheral oedema (66% vs 51%), compared with those treated by cardiologists (all p<0.001). Hypertension (74% vs 66%), previous stroke and/or transient ischaemic attack (21% vs 16%), diabetes (40% vs 30%), and chronic obstructive pulmonary disease (14% vs 11%) were more common in outpatients of GPs (all p<0.001). GPs were less likely to prescribe β-blocker (95% vs 97%, p<0.01), mineralocorticoid receptor antagonist (MRA) (56% vs 64%, p<0.001), and loop diuretic (61% vs 64%, p<0.05) or use PCI (33% vs 44%, p<0.001), CABG (11% vs 16%, p<0.001), ICD (4% vs 10%, p<0.001), or CRT (1% vs 5%, p<0.001). Prescription of renin-angiotensin system inhibitors (94% vs 94%, p>0.2) and digoxin (20% vs 21%, p>0.2) by GPs and cardiologists was similar.

CONCLUSION

In contemporary Poland, most outpatients with HFREF receive drugs that improve survival and undergo revascularisation procedures, although devices are rare, but the clinical profiles and management of those treated by GPs and cardiologists differ. Outpatients treated by GPs are older and have more co-morbidities. Outpatients treated by cardiologists more commonly receive β-blocker, MRA, ICD, and CRT, and undergo coronary revascularisations.

[Acute and chronic heart failure in light of the new ESC guidelines]

In June 2012, the New Guidelines for the Treatment of Acute and Chronic Heart Failure of the European Society of Cardiology were published. According to the EMPHASIS-HF trial, mineralocorticoid receptor antagonists are indicated in all stages of symptomatic chronic heart failure under treatment with β-blockers and ACE inhibitors. Based on the SHIFT trial, patients with class NYHA II-IV heart failure, an ejection fraction <35%, and sinus rhythm with a heart rate of >70/min despite pharmacological treatment including β-blockers at the maximum tolerated dose should be treated with ivabradin. The RAFT trial justified the extended indication for CRT systems. In acute heart failure, the RELAX-AHF trial showed promising results with serelaxin. This manuscript summarizes the innovations of the new guidelines and the underlying clinical trials.

Registry in Germany focusing on level-specific and evidence-based decision finding in the treatment of heart failure: REFLECT-HF

BACKGROUND

In Germany, care for patients with chronic heart failure (HF) is provided by hospital-based cardiologists (HBC), office-based cardiologists (OBC) and general practitioners (GP). We aimed to compare patient characteristics, diagnostic approaches and therapeutic decisions.

METHODS

Multi-centre, cross-sectional, observational survey at 48 physicians. Patients (n = 384) were required to have previously diagnosed HF and NYHA class ≥ II and/or a left ventricular ejection fraction of <50 %. A total of 384 patients were included at 5 HBCs, 26 OBCs and 18 GPs.

RESULTS

A mean of 18.8 % of all patients at HBCs practices had heart failure, compared to a smaller proportion of 13.9 and 6.7 % at OBCs and GPs, respectively. Echo facility was available for all HBCs and OBCs, but for 16.7 % of GPs (p < 0.0001 for trend). Patients at HBCs had a higher NYHA class (65.6 % had class III/IV; p < 0.0001) compared to 36.8 % at OBCs and 39.3 % at GPs. Usage of three guideline-recommended pharmaceutical treatments was more than 80 %: diuretics (83.1 %), renin-angiotensin system blocking agents (91.4 %) and betablockers (90.1 %) with no differences between physician groups. Mineralocorticoid receptor antagonists (MRAs, overall 47.7 %) were more frequently prescribed by OBCs (54.7 %; p = 0.0007 for trend) than HBCs (43.8 %) and GPs (31.0 %). Ivabradin was not frequently used (11.0 % at OBCs, 4.9 % at HBCs and 0 % at GPs; p = 0.0163 for trend). The proportion of patients with CRT (8.6 %), ICD (23.5 %) and CABG (23.1 %) was not statistically different between groups.

CONCLUSION

REFLECT-HF demonstrates that there are some differences in evidence-based treatment decisions between the three main health services (HBC, OBC and GP) providing care for patients with HF in Germany. Advocating adherence to guideline recommendations and earlier adoption of these evidence-based treatments across all levels of care might further improve patient care.

Ivabradine: potential clinical applications in critically ill patients

It has been extensively demonstrated that an elevated heart rate is a modifiable, independent risk factor for cardiovascular events. A high heart rate increases myocardial oxygen consumption and reduces diastolic perfusion time. It can also increase ventricular diastolic pressures and induce ventricular arrhythmias. Critical care patients are prone to develop a stress induced cardiac impairment and consequently an increase in sympathetic tone. This in turn increases heart rate. In this setting, however, heart rate lowering might be difficult because the effects of inotropic drugs could be hindered by heart rate reducing drugs like beta-blockers. Ivabradine is a new selective antagonist of funny channels. It lowers heart rate, reducing the diastolic depolarization slope. Moreover, ivabradine is not active on sympathetic pathways, thus avoiding any interference with inotropic amines. We reviewed the literature available regarding heart rate control in critical care patients, focusing our interest on the use of ivabradine to assess the potential benefits of the drug in this particular setting.

Reduction of heart rate by omega-3 fatty acids and the potential underlying mechanisms

An elevated resting heart rate is one of the strongest predictors of cardiovascular mortality and is independently associated with sudden cardiac death (SCD). Agents capable of reducing heart rate without significant side effects are therefore of particular interest for the prevention of SCD. Recent human and animal studies have shown that omega-3 fatty acids can reduce heart rate. Our work has shown that omega-3 fatty acids significantly reduce membrane electrical excitability of the cardiac myocyte by lowering its resting membrane potential and the duration of the refractory period through inhibition of ion channels. We propose that these actions may be the underlying mechanisms for the omega-3 fatty acid-induced reduction of heart rate observed in both humans and animals. The heart rate-lowering capability of omega-3 fatty acids may contribute to their preventive effect against SCD.