The SELEQT-HF (SELEnium and CoQ10 NuTrition for Heart Failure) Study Will Evaluate the Effect of Adding Selenium/and coQ10 on Top of Standard HF Therapy in Patients With HF and Will do so Using a Pragmatic, Registry Based Randomized Controlled Trial in the Netherlands.

This randomized controlled trial will be a pragmatic registry based clinical trial (RBRCT), using existing infrastructure on quality reporting of cardiovascular disease management in the Netherlands. This registration platform (Netherlands Heart Registration (NHR) forms the basis of incorporating information of patients with HF in hospitals in the Netherlands. Using the data gathered through this registry, these data will serve as source documentation for the electronic case report form of the current RBRCT and requires only limited additional information. Through the same system, randomization, (Serious) adverse event reporting, endpoint reporting and investigational product allocation will be conducted. Investigational product (selenium/CoQ10 supplementation or placebo) will be distributed from central pharmacy to the home of the patient. Apart from telephone calls at 6 months after randomization and every 12 months thereafter, there will be no study visits and the data gathering will be conducted through routine clinical care and registrations that are already in place. SELEQT-HF is an event driven RBRCT, with an expected median follow up of 2 years.

• Selenium/CoQ10 (Dietary supplement): Oral dosage of twice daily Selenium/CoQ10 (2 x 100 μg selenium tablets (SelenoPrecise 100 μg, Pharma Nord, Denmark) and 2 x 100 mg Q10 capsules (Bio-Quinon 100 mg B.I.D, Pharma Nord, Denmark)
• Matching Placebo (B) (Drug): Matching Placebo

Primary outcomes

• Composite of repeated HF hospitalization, repeated urgent HF visits and cardiovascular death [ongoing, up to ~30 months]: Total (first and subsequent) HF hospitalizations, urgent visits for HF visits and cardiovascular deaths with selenium/coQ10 compared to placebo.

Secondary outcomes

• Total number of events of (repeated) HF hospitalization and (repeated) urgent HF visits [ongoing, up to ~30 months]: Total number of (repeated) HF hospitalization and (repeated) urgent HF visits
• Time to death from any cause [ongoing, up to ~30 months]: time to death from any cause with selenium/coQ10 compared to placebo
• Time to cardiovascular death [ongoing, up to ~30 months]: Time to cardiovascular death with selenium/coQ10 compared to placebo

Other outcomes

• Total number of (repeated) all cause hospitalizations [ongoing, up to ~30 months]: Total number of (repeated) all cause hospitalizations with selenium/coQ10 compared to placebo
• Total number of (repeated) unscheduled cardiovascular hospital visits [ongoing, up to ~30 months]: Total number of (repeated) unscheduled cardiovascular hospital visits with selenium/coQ10 compared to placebo
• Total days alive out of hospital [ongoing, up to ~30 months]: Total days alive out of hospital with selenium/coQ10 compared to placebo
• Side effects associated with study supplement [ongoing, up to 30 months]: Side effects associated with study supplement

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* Age >18 years
* Outpatients with chronic HF, NYHA II - ambulatory IV
* Serum NT-proBNP concentrations >600 pg/mL (71 pmol/L) if in sinus rhythm; >1000pg/mL (118 pmol/L) if in Atrial fibrillation*

Exclusion Criteria:

* History of myocardial infarction, myocarditis, percutaneous intervention, cardiac surgery or stroke <30 days
* The presence of a mechanical assist device
* Scheduled for mechanical assist device or heart transplant
* Other non-cardiac conditions with limited life expectancy (<1 year)
* Amyloid, hypertrophic obstructive or constrictive cardiomyopathy
* End stage kidney disease for which chronic intermittent peritoneal or haemodialysis
* Unable to sign informed consent
* (Unwilling to stop) use of over the counter supplements coQ10/selenium
* Peanut and/or soy allergy

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• Peter van der Meer, prof dr, Principal investigator, University Medical Center Groningen
• Jeroen Schaap, MD,PhD, Principal investigator, Amphia Hospital Breda