Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

543 results found
Article

Sigmoid shaped interventricular septum

A sigmoid-shaped interventricular septum is considered an anatomical variant which gives the interventricular septum a sigmoid or S like contour. It may be more common in elderly patients. It has been occasionally be associated with syncope 1 and mild ventricular obstruction 2.
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Single chamber cardiac pacers

Single chamber cardiac pacemakers are cardiac conduction devices with one lead terminating in (most commonly) the right ventricular apex or the right atrium.  Components Includes one of the following:  lead in the right atrium  lead in the right ventricle Function Single chamber atrial pac...
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Single coronary artery

Single coronary arteries are rare (incidence 0.03-0.07%), with a higher incidence in patients with congenital heart disease (in particular truncus arteriosus and pulmonary atresia). They occur when there is a single ostia arising from the aorta with no ectopic ostia. There is a wide variety of c...
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Sinoatrial nodal artery

The sinoatrial (SA) nodal artery is the small artery that supplies the sinoatrial (SA) node of the heart (the pacemaker).  Gross anatomy Origin Right coronary artery in 60% of cases and the left coronary artery in 40% of cases. Course The artery turns posteriorly below the superior vena cav...
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Sinus of Valsalva

The sinuses of Valsalva, also known as aortic sinuses, are the anatomic spaces at the aortic root bounded internally by the aortic valve leaflets and externally by outward bulges of the aortic wall. In typical anatomy, there are three sinuses: right coronary or anterior gives rise to right co...
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Sinus of Valsalva aneurysm

Sinus of Valsalva aneurysms are a cause of thoracic aortic dilatation, arising from one of the aortic sinuses. They can be either congenital or acquired (mycotic). Epidemiology There is a male predilection (M:F ratio being around 3-4:1). They are relatively more common in eastern and Asian pop...
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Small cardiac vein

The small cardiac vein is a vein of the heart which accompanies the acute marginal artery from the RCA. It courses in the right posterior atrioventricular groove and drains into the coronary sinus close to it’s termination but may drain directly into the right atrium. It drains the right ventric...
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Snowman sign (total anomalous pulmonary venous return)

Snowman sign refers to the configuration of the heart and the superior mediastinal borders resembling a snowman. This is seen in total anomalous pulmonary venous return (TAPVR) type I (supracardiac type). It is also referred to as the figure of 8 sign. It is an abnormality of the fetal circulat...
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Sonographic approach to dyspnea (mnemonic)

This mnemonic will help with the sonographic approach to the critically ill patient with dyspnea: CHEST Mnemonic C: collapsed lung (pneumothorax)  absence of anterior lung sliding, lung pulse, B-lines, or z-lines these artifacts arise from the pleural interface; their presence would rule ou...
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Speckle tracking echocardiography

Speckle tracking echocardiography describes the semi-automated analysis of grey scale (B-mode) echocardiographic studies in which the spatial translocation of derived functional units (speckles) allows quantitative analysis of myocardial function. Speckle tracking constitutes a subset of deform...
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Spectral Doppler (ultrasound)

Utilizing automated Fourier analysis to convert returning sound waves into a series of individual frequencies, spectral Doppler refers to ultrasound modalities which yield graphical representations of flow velocity over time.  Terminology The frequency of the sound waves returned to an ultraso...
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Stanford classification of aortic dissection

Along with the DeBakey classification, the Stanford classification is used to separate aortic dissections into those that need surgical repair, and those that usually require only medical management. The Stanford classification divides dissections by the most proximal involvement: type A: A aff...
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Straight left heart border sign

Straight left heart border sign is a recently described finding on chest radiograph. It is a fairly specific (84%) sign of hemopericardium after a penetrating chest trauma, although sensitivity at 40% is relatively poor. Positive predictive value (PPV) was found to be 89% 1. It is different to ...
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Stunned myocardium

Stunned myocardium refers to a situation in which an acute transient myocardial ischemic event results in a prolonged wall motion abnormality which eventually resolves. The term is usually distinguished from "hibernating" myocardium, in which a chronic ischemic process leads to chronic left ven...
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Superior aortic recess

The superior aortic recess is one of the pericardial recesses forming a small space within the pericardium, which arises from the superior margin of the transverse pericardial sinus and surrounds the root of the ascending aorta. Its components are variable and may be further subdivided into: a...
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Superior cavoatrial junction

The superior cavoatrial junction (SCAJ), generally referred to as simply the cavoatrial junction (CAJ), is the junction of the right lateral border of the superior vena cava (SVC) and the superior border of the right atrium. It is an important landmark to recognize because it marks an optimum s...
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Surgical hemostatic material

Surgical hemostatic material is used to control bleeding intraoperatively and is hence frequently intentionally left in the operative bed, not to be confused with a gossypiboma which is caused by foreign material left behind in error. Its use has increased with the advent of minimally invasive s...
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Surgically-created cardiac shunts (mnemonic)

A mnemonic for surgically-created cardiac shunts for congenital heart disease is: Great Flow Really Would Be Perfect​ The mnemonic is ordered by the position of the shunt antegrade to normal blood flow through the heart, proceeding from the systemic venous system into the right heart, and then...
Article

Syphilis

Syphilis is the result of infection with the gram negative spirochete Treponema pallidum, subspecies pallidum. It results in a heterogeneous spectrum of disease with many systems that can potentially be involved, which are discussed separately.  Epidemiology Despite the discovery of penicillin...
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Systemic hypotension

Systemic hypotension - or often just - hypotension - is the presence of an abnormally low blood pressure. This may be relative, so that a poorly-controlled hypertensive patient who runs a normal blood pressure at 160/100, may be severely hypotensive at 80/60. Hypotension is usually defined with...
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Systemic lupus erythematosus (thoracic manifestations)

Thoracic manifestations of systemic lupus erythematosus can be variable.  For a general discussion, and for links to other system specific manifestations, please refer to the article on systemic lupus erythematosus.  Pathology Pleuropulmonary manifestations pleuritis: considered one of the c...
Article

Systolic anterior motion (SAM) of the mitral valve

Systolic anterior motion (SAM) of the mitral valve is defined as displacement of the distal portion of the anterior leaflet of the mitral valve toward the left ventricular outflow tract obstruction. It can occur in patients with and without hypertrophic cardiomyopathy.
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Tachycardia induced cardiomyopathy

Tachycardia induced cardiomyopathy (TIC) (or tachycardiomyopathy) is considered a reversible form of acquired cardiomyopathy where there is impaired left ventricular systolic dysfunction precipitated by a tachycardia or a tachyarrhythmia. Typically there is an impairment left ventricular systol...
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Takeuchi procedure

The Takeuchi procedure refers to a direct anastomosis of the anomalous left coronary artery from the pulmonary artery directly to the aorta was described in the 1970s and currently remains the procedure of choice. An intrapulmonary aortocoronary tunnel or baffle was performed by Takeuchi prior ...
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Takotsubo cardiomyopathy

Takotsubo cardiomyopathy (TC) is a condition characterized by transient regional abnormal cardiac wall motion, not defined to a single coronary arterial territory. It has been described predominantly in postmenopausal women, often following exposure to sudden, unexpected emotional or physical st...
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Taussig-Bing anomaly

Taussig-Bing anomaly is a rare congenital heart malformation and is one of the variants of double outlet right ventricle. It consists of transposition of the aorta to the right ventricle and malposition of the pulmonary artery with subpulmonary ventricular septal defect. History and etymology ...
Article

Tc-99m sestamibi

Tc-99m sestamibi (also known as sesta-methoxyisobutylisonitrile) is one of the technetium radiopharmaceuticals.  Characteristics photon energy: 140 KeV physical half-life: 6 hours normal distribution: thyroid, parathyroid, heart (myocardium) excretion: hepatobiliary and renal target organ:...
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Technetium agents

Technetium agents based on the technetium-99m (Tc-99m) radioisotope are frequently used agents in medical imaging. A radiopharmaceutical labeled with 99mTc constitutes a coordination complex in which ligands bond to a central atom of 99mTc by coordinate covalent bonds 4 . The radioactive techne...
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Temporary ventricular assist devices

Temporary ventricular assist devices (or temporary VADs) are temporary percutaneous devices used in supporting a failing heart in cardiogenic shock or perioperatively. Principle Temporary VADs consist of an inlet, outlet and impeller pump all housed within a catheter. Temporary VADs are insert...
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Tetralogy of Fallot

Tetralogy of Fallot (TOF) is the overall most common cyanotic congenital heart condition with many cases presenting after the newborn period. It has been classically characterized by the combination of ventricular septal defect (VSD), right ventricular outflow tract obstruction (RVOTO), overridi...
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Tetralogy of fallot (mnemonic)

A mnemonic for the underlying anatomic defects in tetralogy of Fallot is: PROVe Mnemonic P: pulmonary stenosis R: right ventricular hypertrophy O: overriding aorta V: ventricular septal defect
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Thallium-201 chloride

Thallium-201 chloride (TlCl) is a radiopharmaceutical used primarily in cardiac imaging. Thallium-201 is an analog of potassium; it is produced in cyclotron by bombarding thallium-203 with protons. Characteristics thallium is a monovalent cation photon energy: 80 keV physical half life: 73 h...
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Thiamine deficiency

Thiamine deficiency is caused by a low level of thiamine (vitamin B1) in the body, and when severe, a deficiency may manifest in adults as beriberi.There are two main forms: wet beriberi: high-output cardiac failure predominates Shoshin beriberi 3: severe acute wet form with high mortality dr...
Article

Third mogul sign

The third mogul sign can be seen on frontal chest radiograph in the presence of left atrial enlargement. It refers to an extra mogul or bump along the upper left cardiac silhouette just below the left main bronchus. The third mogul sign commonly represents the enlarged left atrial appendage, pa...
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Thoracic aorta

The thoracic aorta is the most superior division of the aorta and is divided into three sections: ascending aorta aortic arch descending aorta The thoracic aorta begins at the aortic valve, located obliquely just to the left of the midline at the level of the third intercostal space. It term...
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Thrombolysis in myocardial infarction (TIMI) risk score

The thrombolysis in myocardial infarction (TIMI) risk score is a prognostic risk stratification system that categorizes the risk of death and ischemic events in patients with unstable angina / non-ST elevation myocardial infarction and provides a basis for therapeutic decision making. It is thou...
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Tissue Doppler imaging (echocardiography)

A variant of pulsed wave Doppler, tissue Doppler imaging (TDI) is a modality in echocardiography that allows measurement of the velocity of myocardial movement throughout the cardiac cycle. Physics Color flow, pulsed wave, and continuous wave Doppler are designed to analyze the Doppler shifts ...
Article

Total anomalous pulmonary venous return

Total anomalous pulmonary venous return (TAPVR) is a cyanotic congenital heart anomaly with an abnormal drainage anatomy of the entire pulmonary venous system. This contrasts with partial anomalous pulmonary venous return (PAPVR) where only part of the pulmonary venous anatomy is abnormal. In T...
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Total repair of tetralogy of Fallot

Total repair of tetralogy of Fallot is a corrective surgical procedure that involves closure of the ventricular septal defect (VSD) and relief of right ventricular outflow tract (RVOT) obstruction. Procedure Most patients with tetralogy of Fallot (TOF) undergo elective surgical repair between ...
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Transcatheter aortic valve implantation (TAVI)

Transcatheter aortic valve implantation or replacement (TAVI/TAVR) is a technique to replace the aortic valve through a transvascular or transapical approach. Compared to traditional open aortic valve replacement with sternotomy and a heart-lung bypass machine, the TAVI technique is less invasiv...
Article

Transesophageal echocardiography

A standard transesophageal echocardiography (TOE, or TEE in US English) is a type of ultrasound using an endoscopic transducer, which is advanced into the esophagus, offering generally superior visualization of the great vessels and posterior cardiac structures than the standard transthoracic ap...
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Transient ischemic dilatation

Transient ischemic dilatation (TID) is a paradoxical phenomenon seen in myocardial perfusion SPECT imaging.   With severe balanced coronary artery disease, myocardial ischemia may result in apparent enlargement of the left ventricular cavity during stress. The cause of this is not entirely clea...
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Transposition of the great arteries

Transposition of the great arteries (TGA) (also known as transposition of the great vessels (TGV)) is the most common cyanotic congenital cardiac anomaly presenting during the newborn period, with cyanosis in the first 24 hours of life. It accounts for up to 7% of all congenital cardiac anomalie...
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Transthoracic echocardiography views

A standard transthoracic echocardiogram consists of five standardized windows which are obtained in a standardized sequence 1. Obtaining views from the left parasternal, apical, subcostal, and suprasternal notch windows is mandatory for a complete echocardiography protocol. The right parasternal...
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Transverse pericardial sinus

The transverse pericardial sinus is the transverse communication between the left and right parts of the pericardial space proper behind the two outflow arteries of the heart.   Gross anatomy It is superior to the left atrium and posterior to the intrapericardial parts of the pulmonary trunk a...
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Traumatic aortic injury in the exam

Getting a film with traumatic aortic injury in the exam is one of the many exam set-pieces that can be prepared for.  This is one of the cases you should look and not speak for 10 seconds as there tends to be a lot of findings on the film of patients with a traumatic aortic injury. Description...
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Tricuspid atresia

Tricuspid atresia is a cyanotic congenital cardiac anomaly which is characterized by agenesis of the tricuspid valve and right ventricular inlet. There is almost always an obligatory intra-atrial connection through either an ASD or patent foramen ovale (PFO) in order for circulation to be comple...
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Tricuspid valve

The tricuspid valve (TV) is one of the four cardiac valves. It is one of the two atrioventricular valves (AVs) and allows blood to flow from the right atrium to the right ventricle. It opens during diastole and closes during systole. The valve has anterior, posterior and septal leaflets (cusps),...
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Tricuspid valve regurgitation

Tricuspid valve regurgitation (TR), also known as tricuspid valve insufficiency or tricuspid valve incompetence (TI), is a valvulopathy that describes leaking of the tricuspid valve (TV) during systole that causes blood to flow in the reverse direction from the right ventricle (RV) into the righ...
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Tricuspid valve stenosis

Tricuspid valve stenosis is a valvulopathy that describes narrowing of the opening of the tricuspid valve between the right ventricle and the right atrium. Epidemiology MS is seen more commonly in women and in countries, generally developing nations, where rheumatic fever is common 1,2. Clini...
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Triple-rule-out CT

Triple-rule-out CT (TRO CT) angiography may be ordered in the setting of acute chest pain to examine the thoracic aorta and the coronary and pulmonary arteries. The protocol helps exclude life-threatening causes of acute chest pain, especially if atypical, or if alternative causes to acute coron...
Article

Troponin

Troponin is a protein of key importance in the functioning of skeletal and cardiac muscle. It forms part of the contractile mechanism, and comprises three main subunits: troponin C, troponin I, and troponin T.  Troponin elevation Elevation of serum troponin can occur from a number of causes an...
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Truncus arteriosus

Truncus arteriosus is a cyanotic congenital heart anomaly in which a single trunk supplies both the pulmonary and systemic circulation, instead of a separate aorta and a pulmonary trunk. It is usually classified as a conotruncal anomaly. It accounts for up to 2% of congenital cardiac anomalies ...
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Tuberous sclerosis

Tuberous sclerosis, also known as tuberous sclerosis complex or Bourneville disease, is a neurocutaneous disorder (phakomatosis) characterized by the development of multiple benign tumors of the embryonic ectoderm (e.g. skin, eyes, and nervous system). Epidemiology Tuberous sclerosis has an in...
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Tuberous sclerosis (diagnostic criteria)

The tuberous sclerosis diagnostic criteria have been developed to aid the diagnosis of tuberous sclerosis and have most recently been updated in 2012 by the International Tuberous Sclerosis Complex Consensus Group (at time of writing - 2019) 1.  Criteria Genetic criteria The identification of...
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Twiddler syndrome

Twiddler syndrome occurs when a patient manipulates (rotates) a subcutaneous chest device to the point of detaching and retracting the distal portion of the device. It is most commonly seen with implanted cardiac pacemakers or implantable cardiac defibrillators (ICDs). With continued rotation, ...
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Uhl anomaly

Uhl anomaly is an unusual cardiac disorder which affects the right ventricle where there is an almost complete absence of right ventricular myocardium, normal tricuspid valve, and preserved septal and left ventricular myocardium. Clinical presentation Presentation usually occurs in the neonata...
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Unifocalisation procedure

A unifocalisation procedure is a corrective surgical technique used in patients with complete pulmonary artery atresia with major aortopulmonary collateral arteries (MAPCAs). In this technique, the collateral vessels supplying blood from the aorta directly to the lungs are brought into continuit...
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Unilateral pulmonary vein atresia

Unilateral pulmonary vein atresia is a type of pulmonary vein atresia. Clinical presentation The condition usually present in infancy or childhood with recurrent episodes of pneumonia and/or hemoptysis. Presentation in adulthood does occur but is uncommon. Pathology It results from failure o...
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Unroofed coronary sinus

An unroofed coronary sinus is a rare variant of atrial septal defect (ASD). The atrial wall between the coronary sinus and left atrium is either partially or completely absent, resulting in a left-to-right shunt. It is associated with persistent left-sided SVC and heterotaxy syndromes. Clinica...
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Upper lobe pulmonary venous diversion

Upper lobe pulmonary venous diversion (cephalisation) reflects elevation of left atrial pressure and can occur with pulmonary edema. It produces stag-antler's sign on a frontal chest x-ray. The normal left atrial pressure is 5-10 mmHg. An elevation of left atrial pressure to 10-15 mmHg will res...
Article

Vagoglossopharyngeal neuralgia

Vagoglossopharyngeal neuralgia is an uncommon presentation of glossopharyngeal neuralgia where the typical symptoms of pain are associated with cardiac symptoms including arrhythmias, asystole, and syncope. It is believed to be due to complex interconnections between the nervus intermedius, the...
Article

Valsalva maneuver

The Valsalva maneuver is the forced expiration of air against a closed airway, resulting in increased intra-abdominal, intrathoracic and pharyngeal pressure. It can be performed against a closed glottis or by one closing the mouth and pinching the nose while forcibly exhaling. It is commonly us...
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Valvular heart disease

Valvular heart diseases, or cardiac valvulopathies, describe any acquired or congenital disease affecting one or more of the four cardiac valves. This is a general index article that classifies cardiac valvulopathies depending on which valve(s) is affected 1. See individual articles for in-dept...
Article

Vein of Marshall

The vein of Marshall, oblique vein of Marshall or the oblique vein of the left atrium is a small vein that descends on and drains the posterior wall of the left atrium. It drains directly into the coronary sinus at the same end as the great cardiac vein, marking the origin of the sinus. It repr...
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Venae cordis minimae

The venae cordis minimae (singular: vena cordis minima), meaning "smallest cardiac veins", also known as thebesian veins (as these are eponymous, they are sometimes capitalized as Thebesian veins) are a small group of valveless myocardial coronary veins within the walls of each of the four cardi...
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Ventricular assist device

Ventricular assist devices (VAD) are a mechanical circulatory support device, which is providing an effective therapy for a significant number of patients with advanced heart failure. There are mostly left VADs, although right VADs are also implanted.  Device elements inflow cannulas  electri...
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Ventricular interdependence

Ventricular interdependence (or ventricular coupling) is a phenomenon whereby the function of one ventricle is altered by changes in the filling of the other ventricle. This leads to increase in volume of one ventricle associated with a decreased volume in the opposite ventricle 1. This conditi...
Article

Ventricular septal defect

Ventricular septal defects (VSD) represent defects in the interventricular septum that allow a hemodynamic communication between the right and left ventricles. It typically results in a left-to-right shunt. Epidemiology They represent one of the most common congenital cardiac anomalies and may...
Article

Walking man sign (chest x-ray)

The walking man sign is seen on a lateral chest radiograph and is a sign of left atrial enlargement. It results from posterior displacement of the left main bronchus such that it no longer overlaps the right bronchus. The left and right bronchus thus appear as an inverted 'V', mimicking the legs...
Article

Wall motion score index (echocardiography)

Calculation of the left ventricular wall motion score index (WMSI) with transthoracic echocardiography allows the semi-quantification of left ventricular ejection fraction (LVEF). Calculation of the LVEF with a WMSI demonstrates stronger agreement with measures obtained by cardiac MRI, the gold ...
Article

Watchman device

Watchman device is a permanent left atrial appendage closure device, which is percutaneously implanted to prevent embolization of thrombus from the appendage into the systemic circulation in cases atrial fibrillation. It is used when there is contraindication to anticoagulation or high risk of l...
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Waterston shunt

A Waterston shunt is a form of palliative surgery performed in patients with tetralogy of Fallot prior to the ability to repair the defect. It consists of a shunt formed between the ascending aorta and the right pulmonary artery. This does not relieve the right ventricular outflow obstruction, ...
Article

Wellens syndrome

Wellens syndrome (also referred to as LAD coronary T-wave syndrome) refers to an ECG pattern specific for critical stenosis of the proximal left anterior descending artery. The anomalies described occur in patients with recent anginal chest pain, and do not have chest pain when the ECG is record...
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Wells criteria for pulmonary embolism

The Wells criteria for pulmonary embolism is a risk stratification score and clinical decision rule to estimate the probability for acute pulmonary embolism (PE) in patients in which history and examination suggests acute PE is a diagnostic possibility. It provides a pre-test probability which, ...
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White coat effect

The white coat effect, not to be confused with white coat hypertension, is a measure of change that is commonly defined as the difference between in-clinic and out-of-clinic blood pressure readings 1,2.  Alternatively, the white coat effect can be defined as the increase in the arterial blood p...
Article

Williams syndrome

Williams syndrome (WS) is characterized by some or all of the following features: craniofacial dysmorphism (e.g. elfin facies) oral abnormalities short stature (50% of cases) mild to moderate intellectual disability  supravalvular aortic stenosis 2 pulmonary artery stenosis 3 renal insuff...
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Wolff parkinson white syndrome

The Wolff-Parkinson-White syndrome describes paroxysmal tachydysrhythmias in the presence of a specific accessory pathway (AP) which allows direct electrical connection between the atria and ventricles, which usually exclusively occurs via the atrioventricular node. The accessory pathway is usua...

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