17 segment model recommended by American Heart Association (AHA) divides the left ventricle wall into 17 segments to study the wall function and myocardial perfusion.
segment 1: basal anterior
segment 2: basal anteroseptal
segment 3: basal inferoseptal
segment 4: basal infer...
An accessory left atrial appendage is a frequent fortuitous finding in cardiac imaging, encountered in ~10% of patients. They are more often seen as a small diverticular structure projecting from the right upper side of the left atrial wall.
it must not be confused with ...
Acute right heart syndrome (ARHS) is defined as a sudden deterioration in right ventricular (RV) function and failure of the RV to deliver adequate blood flow to the pulmonary circulation. This can result in systemic hypoperfusion.
ARHS can occur in several settings 1
in the setting...
There are numerous causes of acyanotic congenital heart disease and can be divided into those that have increased pulmonary vascularity (pulmonary plethora) and those that do not:
increased pulmonary vascularity
ventricular septal defect (VSD)
atrial septal defect (ASD)
Agatston score is a semi-automated tool to calculate a score based on the extent of coronary artery calcification detected by an unenhanced low-dose CT scan which is routinely performed in patients undergoing cardiac CT. Due to an extensive body of research, it allows for an early risk stratific...
Anomalous course of a coronary artery is a type of congenital coronary artery anomaly. It may represent a benign and incidental finding, but can also be a malignant course predisposing patients to life-threatening myocardial ischaemia or arrhythmias, depending on where the artery runs.
Anomalous left coronary artery from the pulmonary artery (ALCAPA), also known as Bland-White-Garland syndrome (BWG), is a rare congenital coronary artery anomaly and is considered one of the most serious of such anomalies.
There are two forms based on onset of disease each of which has differen...
The aortic annulus is a fibrous ring at the aortic orifice to the front and to the right of the atrioventricular valve and is considered the transition point between the left ventricle and aortic root. It is at the level of the sinus of Valsalva and is the site of aortic valve leaflet insertion....
The aortic isthmus is the part of the aortic arch just distal to the origin of the left subclavian artery at the site of the ductus arteriosus.
This portion of the aorta is partly constricted in the fetus because of the lack of flow within the aortic sac and ascending aorta. It marks the partia...
Aortic valve stenosis (also known as aortic stenosis) is the most common type of valvular heart disease that requires valve replacement. It can be classified according to the anatomical location: supravalvular, valvular and subvalvular 1.
There are several causes of aortic valve ...
Aortopulmonary septal defect (APSD), also known as aortopulmonary window (APW), is a congenital anomaly where there is an abnormal communication between the proximal aorta and the main pulmonary artery in the presence of separate aortic and pulmonary valves.
APSD should not be conf...
Arrhythmogenic right ventricular dysplasia (ARVD) is classified as a type of cardiomyopathy. It is seen particularly in young males, and is one of the more common causes of sudden death in these patients.
The estimated population prevalence is thought to range around 1 in 1000-50...
For the diagnosis of arrthymogenic right ventricular dysplasia to be made patients must have either two major criteria, one major and two minor criteria, or four minor criteria.
global or regional dysfunction and structural alterations:
severe dilatation of the right ventricle ...
In patients with a left ventricular assist device (LVAD), spectral Doppler waveforms are altered due to continuous flow provided by the pump in the device:
waveforms are monophasic with a constant antegrade flow and no flow below the baseline.
the waveform is typically parvus-tardus with a slo...
The arterial switch procedure (or Jatene switch) is an intervention designed to correct D-transposition of the great arteries at the level of the aorta and main pulmonary artery.
First, the left and right coronary arteries are transferred to the posterior artery (the main pulmonary artery, now ...
Atrial escape refers to a chest x-ray sign of massive left atrial enlargement and is an exaggerated version of the double density sign.
Normally, the right border of the left atrium is not visible. As it enlarges it forms a distinct border projecting through the right heart shadow, medial to ...
Atrial septal defects (ASD) are the second most common congenital heart defect after ventricular septal defects and the most common to become symptomatic in adulthood.
They are characterised by an abnormal opening in the atrial septum allowing communication between the right and left atria. Due...
Atrial-oesophageal fistulas are rare pathological connections between the left atrium and the oesophagus.
The presentation is non-specific. Patients may complain of fever, malaise, dysphagia or present with neurological symptoms 3.
The chief cause of atrial-...
Atrioventricular septal defects (AVSDs), also known as atrioventricular canal defects or endocardial cushion defects, comprise of a relatively wide range of defects involving the atrial septum, ventricular septum and one or both of the tricuspid or mitral valve. They can represent 2-7% of congen...
Barth syndrome (BTHS), also referred to as 3-methylglutaconic aciduria type II is an extremely rare X-linked multi-system disorder that is usually diagnosed in infancy.
It is characterised by:
fetal cardiomyopathy: (dilated fetal cardiomyopathy (DCM) +/- endocardial fibroelastosis (EFE) +/- le...
Beck triad is a collection of three clinical signs associated with pericardial tamponade which is due to excess accumulation of fluid within the pericardial sac. The three signs are:
low blood pressure (weak pulse or narrow pulse pressure)
muffled heart sounds
raised jugular venous pressure ...
Bentall procedure is performed for the repair of ascending aortic root lesions. Typically the native aortic root and aortic valve are replaced with a composite graft that comprises of both ascending aortic and aortic valve grafts, into which the coronary arteries are anastomosed.
History and et...
Bicuspid aortic valve (BAV) refers to a spectrum of deformed aortic valves with two functional leaflets or cusps which are often unequal in size.
They are most often congenital while an acquired bicuspid valve occurs when there is fibrous fusion between the right and left cusps of a pre-existin...
Blalock-Taussig shunt, also known as Blalock-Thomas-Taussig shunt, is a palliative procedure performed in patients with tetralogy of Fallot (prior to the ability to repair the defect) to increase the pulmonary blood flow.
Originally the shunt sacrificed the subclavian artery (with a distal lig...
Blocked premature atrial contractions (BPACs) are considered a type cardiac bradyarrhythmia and if occurring in utero is classified under a fetal bradyarrhythmia.
It is seen when a premature atrial contraction occurs very early on and consequently it is not conducted into the v...
A 'boot-shaped' heart ("cœur en sabot" in French) is the description given to the appearance of the heart on plain film in some cases of Tetralogy of Fallot. It describes the appearances of an upturned cardiac apex due to right ventricular hypertrophy and a concave pulmonary arterial s...
A 'box-shaped' heart is a radiographic description given to the cardiac silhouette in some cases of Ebstein anomaly. The classic appearance of this finding is caused by the combination of the following features:
huge right atrium that may fill the entire right hemithorax
shelved appearance of ...
The Cabrol shunt or Cabrol fistula, also known as a perigraft-to-right atrial shunt, is a technique used for uncontrolled bleeding following aortic root operations.
The Cabrol shunt is applied when bleeding from an aortic root reconstruction cannot be controlled by traditional means ...
Carcinoid cardiac lesions are a known complication of carcinoid tumours, and are particularly prevalent in those who develop the carcinoid syndrome (up to 50%).
There is thickening of mural and valvular endothelial surfaces of right-sided cardiac structures. This is thought to occur ...
Cardiac amyloidosis is a significant source of morbidity among patients with systemic amyloidosis, and is the most common cause of restrictive cardiomyopathy outside the tropics.
Amyloidosis represents the extra-cellular deposition of insoluble fibrillar proteinaceous material in various organs...
Cardiac angiosarcomas are the most common sarcoma involving the heart (see cardiac tumours).
Epidemiology and clinical presentation
As these tumours tends to occur in the right atrium and involve the pericardium, patients usually present with right-sided heart failure or cardiac tamponade. Th...
A multi-gated (MUGA) cardiac blood scan scan is a common study performed in patients who are receiving potentially cardiotoxic chemotherapy.
acute myocardial infarction (AMI)
coronary artery disease (CAD)
evaluation after coronary artery bypass graft surgery
cardiomyopathy / my...
Cardiac chamber enlargement can be recognised by cardiac contour changes, new or different interfaces with adjacent lung, and/or displacement of adjacent mediastinal structures. These are discussed separately:
right atrial enlargement
right ventricular enlargement
left atrial enlargement
Cardiac cirrhosis is the end-point of passive hepatic congestion from heart failure.
Causes of cardiac cirrhosis include 1:
ischaemic heart disease (~30%)
valvular heart disease (~25%)
restrictive lung disease (~15%)
pericardial disease (~10%)
Implantable cardiac conduction devices are a very common medical device of the thorax, with over one million implanted in the United States of America alone.
There are two major types of cardiac conduction devices: pacemakers and automatic implantable cardioverter-defibrillators (AICD/ICD), and...
Computed tomography of the heart (or cardiac CT) is routinely performed to gain knowledge about cardiac or coronary anatomy, to detect or diagnose coronary artery disease, to evaluate patency of coronary artery bypass grafts or implanted coronary stents or to evaluate volumetry and cardiac funct...
The cardiac curriculum is one of our curriculum articles and aims to be a collection of articles that represent the core cardiac knowledge.
Topics pertaining to the heart and pericardium, but excluding the mediastinum (see: chest curriculum) and great vessels (see: vascular curricul...
A cardiac fibroma (also known as cardiac fibromatosis, fibrous hamartoma, or fibroelastic hamartoma) represents a collection of fibroblasts interspersed among large amounts of collagen (some authors believe that this tumour is a hamartoma rather than a neoplasm).
Cardiac fibroma i...
Cardiac herniation is refers to herniation of heart outside its expected position. It can be intrathoracic or extrathoracic.
A cardiac herniation secondary to pericardial rupture is rare, but a highly lethal injury with most patients dying before arrival at a hospital.
Diagnosis in ...
Cardiac imaging planes are used to orientate imaging in cardiac MRI, and are reconstructed for cardiac CT. There are three main planes, which are centred on a line (using body imaging planes) from the cardiac apex to the middle of the mitral valve (a.k.a. true long axis) 1,2:
short axis plane
Cardiac lipomas are uncommon benign primary cardiac neoplasms and occur across a wide age range.
They are soft and may grow to a large size without causing symptoms and are usually incidentally discovered. In the pericardial space, they may compress the ventricles or cau...
Cardiac lymphoma is a rare tumour of the myocardium and/or pericardium. It may be considered as primary or secondary.
Primary cardiac lymphoma is a rare occurrence, representing only 10% of primary malignant cardiac tumours (1% of all primary cardiac tumours).
Cardiac MRI consists of using MRI to study heart anatomy and pathology.
Main advantages of cardiac MRI in comparison with other techniques are:
a better definition of soft tissues
use of different types of sequences improves diagnostic accuracy
avoid ionising radiation
Cardiac myxomas, although uncommon are one of commonest primary cardiac tumours and account for ~50% primary benign cardiac tumours.
Cardiac myxomas are the most common primary cardiac tumour in adults but are relatively infrequent in childhood, where cardiac rhabdomyomas are mor...
The cardiac plexus is a plexus of nerves situated at the base of the heart. It is formed by cardiac branches derived from both the sympathetic and parasympathetic nervous systems.
Sympathetic cardiac nerves are derived from T1 to T4 segments and partly from the T5 segment of the ...
Cardiac rhabdomyomas are a type of benign myocardial tumour, and are considered the most common fetal cardiac tumour.
Cardiac rhabdomyomas are often multiple and can represent up to 90% of cardiac tumours in the paediatric population 1. The majority are diagnosed before the age o...
Cardiac rhabdomyosarcoma is a muscular tumour that arises in the heart.
They account for only 4-7% of cardiac sarcomas overall but are the most common cardiac malignancy in infants and children. There is a slight male predilection.
Cardiac rhabdomyosarcoma ha...
Cardiac silhouette refers to the outline of the heart as seen on frontal and lateral chest radiographs and forms part of the cardiomediastinal contour. The size and shape of the cardiac silhouette provide useful clues for underlying disease.
From the frontal projection, t...
Cardiac tamponade is the result of accumulation of fluid, pus, blood, gas, or benign or malignant neoplastic tissue within the pericardial cavity, which can occur either rapidly of gradually over time, but eventually results in impaired cardiac output.
This is to be distinguished from a pericar...
Cardiac tuberculosis refers to the rare infection of the cardiac musculature with Mycobacterium tuberculosis.
Generally associated with and occurring as a complication of mediastinal and pulmonary tuberculosis.
Pericardial and myocardial involvement is known. Endocardial spread may ...
The four heart valves direct the flow of blood during the cardiac cycle.
The heart valves are located in the cardiac fibrous skeleton:
two are atrioventricular (AV) valves: the right-sided tricuspid valve and left-sided mitral (bicuspid) valve
open during diastole to direct blo...
Cardiac venous malformations (also known as cardiac haemangiomas) consists of a slow flow venous malformation and is composed of numerous non-neoplastic endothelial-lined thin-walled channels with interspersed fat and fibrous septae.
It is important to note that according to newer ...
Cardiomegaly is a catch-all term to refer to enlargement of the heart, and should not be confused with causes of enlargement of the cardiomediastinal outline, or enlargement of the cardiac silhouette.
Although in most cases merely 'eye-balling' a chest x-ray will be sufficient in detecting car...
Cardiomyopathy is defined as a "disease of the myocardium with associated cardiac dysfunction" 1.
It has been classified according to several systems
1995 WHO/ISFC cardiomyopathy classification system:
Elliott et al classification system: published by the European Society of Cardio...
Cardiomyopathy classification separates the various cardiomyopathies into several subtypes. A cardiomyopathy is defined as a "disease of the myocardium with associated cardiac dysfunction".
It was initially classified according to the 1995 WHO/ISFC system as follows:
Cardiomyopathy in haemochromatosis refers to an iron overload cardiomyopathy which can occur in those with the condition.
In primary haemochromatosis leading to iron overload, the cardiomyopathy has classically categorised as an infiltrative cause of restrictive cardiomyopathy. While in those w...
Cardiovascular (cardiac) shunts are abnormal connections between the pulmonary and systemic circulations. Most commonly they are the result of congenital heart disease.
Blood can either be shunted from the systemic circulation to pulmonary circulation (left-to-right shunt) or between...
Carotid pacemaker, also known as implantable carotid sinus stimulators, is a device that delivers activation energy through the carotid leads and the leads conduct activation energy to the carotid baroreceptors. This is sometimes offered for drug-resistant hypertension. The baroreceptors send si...
The causes of pulmonary arterial hypertension are protean and can be divided in many ways. A simple and systematic approach is to proceed along the cardiopulmonary pulmonary circulation, as causes are found at each site (for a more official classification system see 2003 third world symposium on...
Pulseless electrical activity is a very disconcerting medical scenario with a very high mortality unless its aetiology can be quickly ascertained and corrected. A mnemonic to remember the different causes of pulseless electrical activity is:
MAD (triple H) Cat
M: massive pulmonary em...
The superior cavo-atrial junction, generally referred to as simply the cavo-atrial 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 recognise because it marks an optimum site f...
Cervical aortic arch is a rare anomaly characterised by an elongated, high-lying aortic arch extending at or above the level of the medial ends of the clavicles.
Patients with cervical aortic arch are usually asymptomatic. Symptomatic patients may present with 1-13:
Chagas disease, also referred as trypanosomiasis, is a tropical parasitic infection with a wide spectrum of clinical manifestations, since it can virtually affect any organ, but there are characteristic radiological features.
Chagas disease is endemic to Central and South America....
The chest x-ray is a ubiquitous tool used in the assessment of a vast number of sick (and potentially sick) patients.
In the early clinical years, it will appear be challenging to interpret. However, with practice and repeated exposure, you will learn to interpret chest x-rays with relative ea...
The circumflex artery (Cx) is a major coronary artery that divides off the left main coronary artery (the other branch being the left anterior descending artery).
The circumflex artery has been referred to with multiple terms:
circumflex artery (Cx)
left circumflex artery (LCx)
To be merged with pericardial agenesis
Congenital absence of the pericardium is rare, and although often asymptomatic, can result in mechanical impairment of cardiac function and even death.
In most cases of isolated absence of the pericardium, patients are asymptomati...
A congenital aortic stenosis broadly refers to a congenital narrowing of the aortic lumen. Although the term can mean narrowing at any point it often refers to a narrowing about the aortic valve. As a broad group there can be some overlap with ascending aortic coarctation depending of the defini...
Congenital coronary artery anomalies (CCAAs) are not common, found only in ~1% (range 0.1-2%) of patients 1,3.The most important finding to look for is the "malignant" course of anomalous coronary artery, namely, does the artery run between big pulsating objects - RVOT and pulmonary ar...
With the advent of echocardiography, and cardiac CT and MRI, the role of chest radiographs in evaluating congenital heart disease has been largely been relegated to one of historical and academic interest, although they continue to crop up in radiology exams. In most instances a definite diagnos...
Congenital pulmonary stenosis (CPS) refers to congenital narrowing of the right ventricular outflow tract, pulmonary valve or pulmonary artery.
The estimated incidence is 1 in 2000 births.
Can be morphologically categorised depending on the relationship to the pulmonar...
Congenital pulmonary venolobar syndrome is a condition comprised of a rare group of cardiac and pulmonary congenital abnormalities occurring variably in combination. The abnormalities include
anomalous pulmonary venous drainage
particularly scimitar syndrome with hypogenic right lung
Congestive cardiac failure (CCF) is a form of cardiac failure which is primarily manifested by the heart inability to pump the volume of blood. It can affect the left (common) or right cardiac chambers or both.
It may be precipitated by intrinsic cardiac or extrinsic factors (which i...
Conotruncal heart defects (CHDs) are group of congenital cardiovascular anomalies. They are a leading cause symptomatic cyanotic cardiac disease diagnosed in utero.
They may account for up to a fifth of all congenital cardiac anomalies diagnosed prenatally 2.
Constrictive pericarditis (or perhaps better termed pericardial constriction) is a type of pericarditis which leads to diastolic dysfunction and potentially symptoms of right heart failure.
No single demographic is affected as there are numerous causes of constrictive pericarditi...
The conus artery is a small early branch off the right coronary artery (RCA) circulation.
The artery has a variable distribution, but usually supplies a region of the anterior interventricular septum and the conus of the main pulmonary artery (hence its name).
Cor pulmonale is defined as an failure of the structure and function of the right ventricle caused by an underlying primary disorder of the respiratory system. It has a generally chronic and slowly progressive course, although acute onset or worsening with life-threatening complications can occu...
Cor triatriatum is an extremely rare and serious congenital cardiac anomaly.
It is thought to account for ~0.1% of all congenital cardiac anomalies 3,4.
Clinical presentation depends on:
degree of stenosis in the fibromuscular membrane
integrity of the ...
Coronary arterial dominance is defined by the vessel which gives rise to the posterior descending artery (PDA), which supplies the myocardium of the inferior 1/3rd of the interventricular septum.
Most hearts (80-85%) are right dominant where the PDA is supplied by the RCA. The remaining 15-20% ...
Coronary arterial ectasia (CAE) refers to diffuse dilatation of the coronary arteries. Under some classification systems there is some overlap with the term coronary arterial aneurysms (which is a more focal dilatation).
It is often defined as dilatation of an arterial segment to a...
The coronary arteries arise just distal (superior) to the aortic valve from the coronary sinuses and supply the myocardium with oxygenated blood. They divide and encircle the heart to cover its surface with a lacy network resembling perhaps a slightly crooked crown.
The typical c...
Coronary artery aneurysms (CAA's) are an uncommon, predominantly incidental finding.
CAA is most common in men 3, likely reflecting the increased rates of atherosclerosis in men compared to women. Prevalence varies in the literature between 0.1-5% 4.
A coronary artery bypass graft (CABG) is placed during a surgical procedure to increase blood flow to the myocardium due to coronary stenoses, usually caused by coronary artery disease. Arteries or veins can be grafted during this procedure.
Long term outcome of coronary artery bypass grafting ...
Coronary artery disease (CAD) is the leading cause of mortality globally.
CAD is asymptomatic in most of the population. When severe enough it can cause angina, or an acute coronary syndrome including myocardial infarction. CAD may also present with heart failure or sudd...
Coronary MR angiography (coronary MRA) is a developing approach to imaging the coronary arteries.
Advantages of coronary MRA include avoidance of the intravenous iodinated contrast and ionizing radiation used in coronary CT angiography and conventional angiography.
A disadvantage of coronary M...
The coronary sinus is the major coronary vein. It returns the majority of the left ventricular blood flow to the right atrium.
The coronary sinus courses along the posterior wall of the left atrium into the left atrioventricular groove. It normally drains into the right atrium. T...
The coronary veins return blood from the myocardium back to the right atrium. Coronary venous anatomy is highly variable, but is generally comprised of:
cardiac veins (drain into the coronary sinus)
great cardiac vein (adjacent to the left anterior descending artery)
Crista terminalis is a smooth muscular ridge in the superior aspect of right atrium. It represents junction between sinus venosus and the heart. It divides the pectinate muscle origin and the right atrial appendages to the right atrium.
Its identification is significant in determination of atri...
A number of entities can present as cyanotic congenital heart disease. These can be divided into those with increased or decreased pulmonary vascularity (pulmonary plethora):
increased pulmonary vascularity
total anomalous pulmonary venous return (TAPVR) (types I and II)
transposition of the ...
Deductive echocardiography is a step-by-step approach in diagnosing and differentiating congenital heart disease.
position of heart
Delayed myocardial enhancement, as seen on cardiac MRI, occurs when gadolinium contrast material seeps into fibrotic or necrotic myocardial tissue. It is due to a number of aetiologies, and has variable appearances.
subendocardial enhancement indicates an ischaemic aetiology
Atrial situs refers to the relative position of cardiac atria in relation to abdominal viscera and the midline.
Identification of atrial situs is an important initial step in the antenatal and postnatal diagnosis of cardiac structural and situs anomalies.
Dextrocardia is a congenital cardiac malrotation in which the heart is situated on the right side of the body (dextroversion) with the apex pointing to the right.
Dextrocardia is believed to occur in approximately 1 in 12,000 people 2.
There are two main types of dextr...
Diagonal branches are branches of the left anterior descending coronary artery. They supply blood flow to the anterior and anterolateral walls of the left ventricle.