72,234 articles
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.
Heart rate response to exercise and training
Heart rate response to exercise and training describes how heart rate rises during exercise, how endurance training lowers resting heart rate, and how quickly heart rate recovers afterward.
Heart rate variability
Heart rate variability (HRV), also called heart period variability, measures beat-to-beat R-R interval variation on the ECG as a non-invasive marker of autonomic nervous system function, analyzed in time and frequency domains (SDNN, RMSSD, LF, HF bands) and applied in cardiology, mental health, and sepsis prediction.
Heart Rhythm
Heart Rhythm: Elsevier monthly journal (ISSN 1547-5271) launched May 2004, official journal of the Heart Rhythm Society and Cardiac Electrophysiology Society, covering cardiac arrhythmias and electrophysiology.
Heart Rhythm Society
Heart Rhythm Society (HRS), formerly NASPE (North American Society of Pacing and Electrophysiology), founded 1979 in Boston; professional society for cardiac pacing and electrophysiology, renamed 2004, 9,700+ members in 93 countries, based in Washington, DC.
HEART score
The HEART score is a bedside risk tool for emergency department chest pain patients, scoring History, ECG, Age, Risk factors, and Troponin to predict major cardiac events within 6 weeks.
Heart sounds
Heart sounds are transient noises from valve closure heard during auscultation. The first two sounds, S1 and S2, are normal, while S3 and S4 are usually abnormal.
Heart transplantation
Heart transplantation: surgical replacement of a failing heart with a donor heart. First done by Barnard in 1967; 1-year survival now near 90%; main risks are rejection, vasculopathy, and immunosuppression side effects.
Heart valve
Heart valve: the four cardiac valves (mitral, tricuspid, aortic, pulmonary), passive pressure-driven leaflet/cusp mechanics, valve disease epidemiology, repair versus replacement, TAVI, and 2024-2025 trial changes.
Heart valve dysplasia
Heart valve dysplasia is a congenital malformation in which one or more heart valves is thickened and malformed, causing regurgitation or stenosis. Includes X-linked FLNA-related cardiac valvular dysplasia and canine tricuspid valve dysplasia.
Heart Valve Prosthesis Implantation
Heart valve prosthesis implantation replaces diseased native valves with mechanical or bioprosthetic devices, surgically since 1952 and by transcatheter methods (TAVI/TAVR) since the early 2000s, with anticoagulation and durability trade-offs.
Heart-type fatty acid binding protein
Heart-type fatty acid binding protein (H-FABP, FABP3) is a 14-15 kDa cytosolic fatty acid transporter abundant in heart and skeletal muscle, used as an early biomarker of myocardial infarction but inferior to high-sensitivity troponin.
Heart–liver transplantation
Heart–liver transplantation is a surgical procedure that replaces both the heart and liver with organs from a single donor, used for combined heart and liver failure and first performed in 1984.
Heart–lung transplantation
Heart–lung transplantation is an operation replacing a patient's heart and both lungs en bloc with donor organs, first done successfully at Stanford in 1981 and now rare, under 50 cases a year worldwide.
Heartburn
Heartburn (pyrosis, acid indigestion): burning chest pain from stomach acid refluxing into the esophagus via a weak lower esophageal sphincter. Over 60 million Americans affected monthly; frequent episodes suggest GERD; treated with antacids, H2 blockers, PPIs.
Heartland bandavirus
Heartland bandavirus (Heartland virus, HRTV) is a tick-borne Bandavirus in Phenuiviridae, discovered in Missouri in 2009, spread mainly by the lone star tick, causing fever with leukopenia and thrombocytopenia; no vaccine or specific treatment exists.
Heartwater
Heartwater, also known as cowdriosis, is a tick-borne rickettsial disease of ruminants caused by Ehrlichia ruminantium and transmitted by Amblyomma ticks across sub-Saharan Africa and the Caribbean.
Heat adaptation of archaeal membranes
Heat adaptation of archaeal membranes is how thermophilic archaea grow at extreme temperatures, through ether-linked isoprenoid lipids, tetraether monolayers, and adjustable cyclization that keep membranes intact above 80°C.
Heat exhaustion
Heat exhaustion is a heat-related illness from excessive water and salt loss through sweating, causing headache, nausea, dizziness, and heavy sweating; treated with cooling and fluids, it can progress to heat stroke if untreated.
Heat fatigue, transient
Heat fatigue, transient (ICD-11 NF01.3) is a mild acute heat effect: impaired performance of skilled sensorimotor, mental, or vigilance tasks in the heat, greatest in unacclimatized workers, prevented by acclimatization and training.
Heat shock protein
Heat shock proteins, also known as stress proteins, are molecular chaperones produced by cells under heat and other stresses, helping other proteins fold and boosting heat tolerance.
Heat stroke
Heat stroke is a life-threatening emergency with core temperature above 40 °C (104 °F) and CNS dysfunction, in classic (passive heat exposure) and exertional (exercise) forms; treatment is rapid cold-water immersion, with about 5% case fatality.
Heat syncope
Heat syncope (熱失神) is fainting or dizziness from prolonged standing or sudden standing in heat, caused by reduced cerebral blood flow; a mild, self-limiting heat illness treated with rest, cooling, and oral fluids.
Heat-killed Clostridium tyrobutyricum protein
Heat-killed Clostridium tyrobutyricum protein, strain ASM#19/SD20/06, is Superbrewed Food's ≥80% protein bacterial biomass ingredient, GRAS per FDA GRN 1129 (no questions, Feb 22, 2024), for foods at 5–90%.
Heat-Shock Response
The heat-shock response is a conserved cellular program triggered by heat and other stresses, in which heat shock proteins refold damaged proteins and protect the cell.
Heath
Heath (heathland): open shrubland on free-draining, infertile acidic soils dominated by ericoid dwarf shrubs like Calluna vulgaris; a human-made European cultural landscape maintained by grazing and burning, threatened by nitrogen deposition and succession to forest.
Heather Allore
Heather Allore is an American biostatistician at Yale School of Medicine known for gerontological biostatistics and studies of disability, falls, and dementia in older adults.