25,729 articles
Healthcare in Nigeria
Healthcare in Nigeria: pluralistic public-private system, decentralized across federal, state, and local government, funded mostly by out-of-pocket payments (76%), with NHIA mandatory insurance since 2022, low spending, and workforce shortages.
Healthcare in South Africa
Healthcare in South Africa: a two-tier public–private system serving about 84% of people publicly, spending 8.27% of GDP, carrying the world's largest HIV population, and reforming financing through the National Health Insurance Act phased in 2024–2028.
Healthcare Near Miss
Healthcare near miss (close call): a patient safety event that presented a risk but caused no patient harm. WHO classifies incidents as near miss, no harm, or harmful; near misses are up to 300 times more common than adverse events but underreported.
Healthy diet
Healthy diet: eating pattern protecting against malnutrition and noncommunicable diseases; WHO principles of adequacy, balance, moderation, diversity; quantitative limits on sugars, fats, salt; DASH and Mediterranean top-rated patterns.
HEALTHY trial
HEALTHY trial (NCT00458029): NIDDK-funded US cluster-randomized primary prevention trial in 42 middle schools, 7 sites, testing a 4-component school intervention against type 2 diabetes risk factors; primary obesity outcome null, secondary adiposity outcomes improved.
Healthy, Hunger-Free Kids Act of 2010
Healthy, Hunger-Free Kids Act of 2010 (P.L. 111-296, S. 3307), US law signed December 13, 2010 reauthorizing child nutrition and WIC programs; set stricter school meal standards, created the Community Eligibility Provision, and its milk rules were reversed by the 2026 Whole Milk for Healthy Kids Act.
Hearing
Hearing: the sense converting sound waves into electrical signals via the ear canal, eardrum, malleus-incus-stapes chain, and cochlear hair cells, with tonotopic coding carried by the auditory nerve to the brain; distinct from balance, the inner ear's other function.
Hearing aid
Hearing aid: wearable medical device amplifying sound for impaired hearing; air- and bone-conduction types, digital signal processing, FDA OTC category since October 2022, styles from BTE to CIC, and global use by only 17% of those who could benefit.
Hearing loss
Hearing loss (deafness): reduced hearing versus 20 dB thresholds, from mild to profound. Types sensorineural, conductive, mixed; 430 million need rehabilitation; first gene therapy (Otarmeni, OTOF) approved 2026.
Hearing range
Hearing range, the span of frequencies and intensities an ear detects; humans hear about 20 Hz to 20 kHz (adults often 15–17 kHz upper limit), best sensitivity 2000–5000 Hz, declining with age.
Hearing research
Hearing Research (Hear Res, ISSN 0378-5955) is an Elsevier peer-reviewed journal founded 1978 in the Netherlands, covering peripheral and central auditory mechanisms, hearing loss, hearing aids, and cochlear implants; 2025 JIF 3.0, Q1.
Hearing screening
Hearing screening, also called newborn hearing screening, uses quick tests such as OAE and AABR to identify infants with permanent hearing loss for early intervention.
Heart and Stroke Foundation of Canada
The Heart and Stroke Foundation of Canada (French: Fondation des maladies du cœur et de l'AVC du Canada), known as Heart & Stroke, is a Canadian charity founded in 1952 that funds heart and brain research.
Heart and vessels
Heart and Vessels (Heart Vessels), English-language peer-reviewed Japanese cardiology journal founded 1985, Springer, ISSN 0910-8327, official journal of the Sakakibara Heart Foundation, MEDLINE-indexed since 1985, 2025 impact factor 1.5.
Heart auscultation
Heart auscultation, also called cardiac auscultation, is the physical examination technique of listening to heart sounds with a stethoscope to detect murmurs, gallops, friction rubs, clicks, and rhythm abnormalities.
Heart block
Heart block (atrioventricular block) is impaired electrical conduction from the atria to the ventricles, graded first to third degree on ECG; causes include degenerative disease, ischemia, and Lyme disease, and higher grades usually need a pacemaker.
Heart failure
Heart failure: clinical syndrome of breathlessness, fatigue, and congestion from cardiac structural or functional abnormality, corroborated by raised natriuretic peptides; classified by ejection fraction (HFrEF, HFpEF), treated with four-pillar drug therapy and, in advanced stages, LVAD or transplant.
Heart failure diagnosis and staging
Heart failure diagnosis and staging is the process of confirming heart failure, classifying it by ejection fraction, and grading it with NYHA class and ACC/AHA stage.
Heart Failure Society of America
Heart Failure Society of America (HFSA), founded 1995, is the first multidisciplinary US specialty society for heart failure, co-publishing ACC/AHA/HFSA guidelines, the Journal of Cardiac Failure, HF-Cert certification, and the Annual Scientific Meeting.
Heart failure with comorbid conditions
Heart failure with comorbid conditions is the management of heart failure in patients who also have diabetes, chronic kidney disease, atrial fibrillation, or iron deficiency, which raise mortality.
Heart failure with mildly reduced ejection fraction
Heart failure with mildly reduced ejection fraction (HFmrEF) is a heart failure classification with a left ventricular ejection fraction of 41% to 49%, between the reduced and preserved categories.
Heart failure with preserved ejection fraction
Heart failure with preserved ejection fraction (HFpEF), also called diastolic heart failure, is a type in which the heart pumps normally but is too stiff to fill, causing congestion.
Heart failure with reduced ejection fraction
Heart failure with reduced ejection fraction, or systolic heart failure, is the heart failure form in which the left ventricle ejects 40% or less of its blood each beat.
Heart Function Tests
Heart function tests measure cardiac electrical activity, pumping strength, valves, and blood flow: ECG, BNP blood tests, echocardiography, cardiac CT and MRI, stress testing, and angiography, with guideline-based selection by patient risk.
Heart murmur
Heart murmur: an extra heart sound from turbulent blood flow, heard on auscultation. Innocent murmurs are common in children; abnormal ones signal valve disease, confirmed by echocardiography.
Heart nanotechnology
Heart nanotechnology applies 1–100 nm materials to cardiac drug delivery, imaging, biosensors, gene therapy, and tissue engineering; also called cardiovascular nanomedicine, it remains mostly preclinical, with about 1% of the nanodrug market versus 20% for cancer.
Heart Protection Study
MRC/BHF Heart Protection Study (HPS): UK randomized 2×2 factorial trial of simvastatin 40 mg and antioxidant vitamins in 20,536 high-risk people; simvastatin cut major vascular events 24%, vitamins showed no benefit.
Heart rate
Heart rate, or pulse, is the number of heartbeats per minute; normal at rest is 60–100 bpm. Set by the sinoatrial node pacemaker and tuned by autonomic, hormonal, and mechanical inputs; measured manually or by wearables and chest straps.
Heart rate across the lifespan
Heart rate across the lifespan describes how heart rate changes with age: about 150 beats per minute in infancy, near 70 in adulthood, with maximum rate declining steadily.
Heart rate monitor
Heart rate monitor: device measuring beats per minute, via chest-strap ECG electrodes or wrist-worn optical PPG in smartwatches and fitness trackers. Chest straps are the validation criterion; wrist accuracy falls as exercise intensity rises.