166 articles
Accessory pathway
Accessory pathway: an abnormal atrioventricular muscle bridge bypassing the AV node, causing pre-excitation (WPW pattern), AVRT, and risk of pre-excited AF; risk-stratified by EP study and cured by catheter ablation.
Accessory tricuspid valve tissue
Accessory tricuspid valve tissue (ORPHA:95462, ICD-10 Q22.8) is a rare congenital tricuspid valve malformation, usually with other congenital heart defects, causing murmurs, dyspnea, cyanosis, or outflow obstruction; treated by surgical excision.
Afterload
Afterload: the mechanical load opposing ventricular ejection, defined as aortic input impedance with steady (SVR) and pulsatile components; also lumped as effective arterial elastance Ea = end-systolic pressure/stroke volume.
Ajmaline
Ajmaline is a class 1A antiarrhythmic alkaloid from the roots of Rauvolfia serpentina, used in Europe and Japan to treat and diagnose abnormal heart rhythms.
Anomalous aortic origin of a coronary artery
Anomalous aortic origin of a coronary artery (AAOCA, ACAOS) is a congenital defect where a coronary artery arises from the wrong aortic sinus; found in up to 1% of people, a leading cause of sudden cardiac death in young athletes, managed by risk stratification and unroofing surgery.
Anomalous aortic origin of the left coronary artery
AAOLCA, anomalous aortic origin of the left coronary artery from the right aortic sinus, a rare congenital coronary anomaly; rarer than the right-coronary form but carrying higher risk of ischemia and sudden cardiac death in young athletes, treated by unroofing surgery.
Anomalous left coronary artery from the pulmonary artery
ALCAPA, or Bland-White-Garland syndrome, is a rare congenital defect where the left coronary artery arises from the pulmonary artery, causing coronary steal, infant heart failure, and over 90% first-year mortality without surgery.
Anomalous origin of coronary artery from the pulmonary artery
Anomalous origin of coronary artery from the pulmonary artery (ACAPA; ALCAPA, Bland-White-Garland syndrome, or ARCAPA): a rare congenital defect causing coronary steal, infant heart failure, about 90% first-year mortality untreated, and surgical reimplantation as the preferred repair.
Anomalous pulmonary venous connection
Anomalous pulmonary venous connection, also called anomalous pulmonary venous return, is a congenital heart defect in which pulmonary veins drain into the systemic venous circulation instead of the left atrium.
Antiarrhythmic agent
Antiarrhythmic agents are drugs for abnormal heart rhythms, grouped by the Vaughan Williams classes I–IV (sodium channel, beta-blocker, potassium channel, calcium channel blockers), extended in 2018 with classes 0 and V–VII; CAST showed class Ic drugs raise post-infarction mortality.
Aortic valve
Aortic valve: the three-cusp semilunar valve between the left ventricle and aorta. Covers anatomy, embryology, bicuspid valve, stenosis and regurgitation criteria, and SAVR, TAVI, and repair options.
Aortopulmonary space
Aortopulmonary space (aortopulmonary window): a mediastinal compartment between aortic arch and left pulmonary artery, and a rare congenital hole between aorta and pulmonary artery requiring patch repair.
Apex beat
Apex beat (apical impulse, point of maximal impulse): the palpable left ventricular impulse, normally in the fifth left intercostal space at the midclavicular line; palpable in about 50% of adults and used to assess cardiomegaly and ventricular character.
Arteriovenous oxygen difference
Arteriovenous oxygen difference (a-v O2 diff, C(a-v)O2): difference between arterial and venous blood oxygen content, about 5 mL/100 mL at rest and 15-20 during exercise; basis of the Fick cardiac output method.
Athletic heart syndrome
Athletic heart syndrome, or exercise-induced cardiac remodeling, is the physiological heart enlargement and electrical change from repetitive strenuous training, first described by Henschen in 1899, and distinguished from cardiomyopathy by reversibility with detraining.
Atrial natriuretic peptide
Atrial natriuretic peptide (ANP, atrial natriuretic factor), a 28-amino-acid cardiac hormone discovered by de Bold in 1981, released on atrial stretch, acting via NPR-A and cGMP to drive natriuresis, vasodilation, and RAAS inhibition.
Atrial septal aneurysm
Atrial septal aneurysm (interatrial septal aneurysm): congenital bulging of the heart's atrial septum over 10 mm into an atrium. Found in about 2.4% of adults by echocardiography; with patent foramen ovale it raises cryptogenic stroke and recurrence risk.
Atrial tachycardia
Atrial tachycardia (AT) is a supraventricular arrhythmia with regular atrial rates above 100 bpm and P waves originating outside the sinus node, caused by automaticity, triggered activity, or microreentry; classified as focal or macroreentrant, treated with drugs and catheter ablation.
Atrioventricular node
The atrioventricular node, or AV node, is a mass of cardiac muscle at the base of the atrial septum that conducts electrical impulses from the atria to the ventricles.
Atrioventricular reentrant tachycardia
Atrioventricular reentrant tachycardia (AVRT), the reentrant arrhythmia of Wolff-Parkinson-White syndrome, uses an accessory pathway plus the AV node as a macroreentrant circuit; orthodromic forms are narrow-complex, antidromic wide-complex, and radiofrequency ablation is curative.
Atrioventricular septal defect
Atrioventricular septal defect (AVSD), also called AV canal or endocardial cushion defect, is a congenital heart defect with holes between heart chambers and a common five-leaflet AV valve, common in Down syndrome, repaired surgically in infancy.
Atrioventricular septum
Atrioventricular septum: septal heart structure between right atrium and left ventricle at the crux, partly membranous and partly muscular. Defects (AVSD) cause 0.24–0.31/1000 live-birth congenital heart disease, strongly linked to Down syndrome; repair mortality about 3%.
Atrium (heart)
Atrium (heart): the two upper heart chambers (right and left atrium) that collect incoming blood. Distinct right pectinate muscles versus smooth left walls, three-phase reservoir-conduit-booster function, and the left atrial appendage as the main AF thrombus site.
Baby Fae
Baby Fae (Stephanie Fae Beauclair, 1984) was the first infant to receive a cross-species heart transplant, a baboon heart implanted by Leonard Bailey at Loma Linda; she lived 21 days.
Bainbridge reflex
Bainbridge reflex (atrial reflex): heart rate rises when venous return and atrial stretch increase, via vagal afferents to the medulla and vagal withdrawal plus sympathetic outflow. Described by F. A. Bainbridge in 1915 in dogs; weaker in humans; linked to respiratory sinus arrhythmia.
Baroreceptor
Baroreceptor: stretch-sensing mechanoreceptor nerve ending in the carotid sinus, aortic arch, and cardiopulmonary circulation; fires via PIEZO, ENaC, ASIC, and TRP channels to the medullary baroreflex, buffering arterial blood pressure.
Beta-1 adrenergic receptor
Beta-1 adrenergic receptor (ADRB1), a cardiac Gs-coupled GPCR activated by norepinephrine; target of beta-1 selective blockers like metoprolol and bisoprolol; gene on chromosome 10q24-q26.
Bezold–Jarisch reflex
Bezold–Jarisch reflex (BJR): cardioinhibitory reflex from left ventricular inferoposterior receptors via vagal C fibers causing bradycardia, vasodilation, hypotension; key in spinal anesthesia asystole, vasovagal syncope, inferior MI.
Bifascicular block
Bifascicular block, also called bifascicular heart block, is an ECG conduction disorder affecting two of three His-Purkinje fascicles (RBBB plus LAFB or LPFB, or LBBB), risking complete AV block, syncope, and pacemaker decisions.
Bigeminy
Bigeminy: a heart rhythm in which every normal beat is followed by a premature ectopic beat, atrial or ventricular. Also called bigeminal rhythm. Causes include heart disease, stimulants and electrolyte imbalance; diagnosed by ECG and Holter; ablation succeeds in 75% or more of cases.