The ostium secundum atrial septal defect is the most common type of atrial septal defect, and comprises 6–10% of all congenital heart diseases.

The secundum atrial septal defect usually arises from an enlarged foramen ovale, inadequate growth of the septum secundum, or excessive absorption of the septum primum. About 10 to 20% of individuals with ostium secundum ASDs also have mitral valve prolapse.

An ostium secundum ASD accompanied by an acquired mitral valve stenosis is called Lutembacher's syndrome.

Most individuals with an uncorrected secundum ASD do not have significant symptoms through early adulthood. More than 70% develop symptoms by about 40 years of age. Symptoms are typically decreased exercise tolerance, easy fatigability, palpitations, and syncope.

Complications of an uncorrected secundum ASD include pulmonary hypertension, right-sided heart failure, atrial fibrillation or flutter, stroke, and Eisenmenger's syndrome.

While pulmonary hypertension is unusual before 20 years of age, it is seen in 50% of individuals above the age of 40. Progression to Eisenmenger's syndrome occurs in 5 to 10% of individuals late in the disease process.

Left to right shunting heart defects include:

- Ventricular septal defect (VSD) (30% of all congenital heart defects)

- Atrial septal defect (ASD)

- Atrioventricular septal defect (AVSD)

- Patent ductus arteriosus (PDA)

- Previously, Patent ductus arteriosus (PDA) was listed as acyanotic but in actuality it can be cyanotic due to pulmonary hypertension resulting from the high pressure aorta pumping blood into the pulmonary trunk, which then results in damage to the lungs which can then result in pulmonary hypertension as well as shunting of blood back to the right ventricle. This consequently results in less oxygenation of blood due to alveolar damage as well as oxygenated blood shunting back to the right side of the heart, not allowing the oxygenated blood to pass through the pulmonary vein and back to the left atrium.

- (Edit - this is called Eisenmenger's syndrome and can occur with Atrial septal defect and ventricular septal defect as well (actually more common in ASD and VSD) therefore PDA can still be listed as acyanotic as, acutely, it is)

Others:

- levo-Transposition of the great arteries (l-TGA)

Acyanotic heart defects without shunting include:

- Pulmonary stenosis (a narrowing of the pulmonary valve)

- Aortic stenosis

- Coarctation of the aorta

Major symptoms of Lutembacher's syndrome as a result of ASD and MS can range from heart failure to pulmonary congestion.

- Right ventricular overload and Right-sided heart failure: Both are caused by a large ASD and MS (moderate to severe).

- Palpitations: This is caused by blood flowing from left atrium to the right atrium causing a higher left atrial pressure and leading to mitral stenosis. Both atria will be dilated (stretched or open)leading to future atrial arrhythmias or atrial fibrillation (Riaz).

- Pulmonary congestion: When blood or fluid pools within the lungs; this is usually a symptom of mitral stenosis and a small ASD.

- Loud mitral S1 and wide fixed split of pulmonary S2: The loud sound of the mitral S1 and the wide fixed split of pulmonary S2 is a symptoms of mitral stenosis. The sounds often are caused by a reduced pressure gradient in the mitral area that was caused from decompression of the left atrium from the ASD and a displacement (moving from normal position) of the left ventricular lower portion of the heart to the a large right ventricle. The second heart sound (S2) split is caused by the increase right heart blood flow through the ASD causing a late closing of the pulmonary component of the S2 as well as decreased left ventricular and aortic blood flow.

- III/IV mid diastolic murmur, early systolic murmur: This heart murmur is caused by an increase blood flow through the tricuspid valve due to ASD; it is heard best in the left lower sternal area or the bottom of the heart (apex).

A defect in the ostium primum is occasionally classified as an atrial septal defect, but it is more commonly classified as an atrioventricular septal defect

In a normal heart, oxygen-depleted ("blue") blood is pumped from the right side of the heart, through the pulmonary artery, to the lungs where it is oxygenated. The oxygen-rich ("red") blood then returns to the left heart, via the pulmonary veins, and is pumped through the aorta to the rest of the body, including the heart muscle itself.

With d-TGA, deoxygenated blood from the right heart is pumped immediately through the aorta and circulated to the body and the heart itself, bypassing the lungs altogether, while the left heart pumps oxygenated blood continuously back into the lungs through the pulmonary artery. In effect, two separate "circular" (parallel) circulatory systems are created, rather than the "figure 8" (in series) circulation of a normal cardio-pulmonary system.

An acyanotic heart defect, also known as non-cyanotic heart defect, is a class of congenital heart defects. In these, blood is shunted (flows) from the left side of the heart to the right side of the heart due to a structural defect (hole) in the interventricular septum. People often retain normal levels of oxyhemoglobin saturation in systemic circulation.

This term is outdated, because a person with an acyanotic heart defect may show cyanosis (turn blue due to insufficient oxygen in the blood).

On ECG superior axis deviation is generally found in primum ASD, but an RSR pattern (M pattern) in V1 is characteristic. Fixed splitting of the second heart sound occurs because of equal filling of the left and right atria during all phases of the respiratory cycle.

Patients with Atrial Septal Defects may have Atrial Fibrillation, Atrial Tachycardia, or Atrial Flutter, but these arrythmias are not usually seen until patients grow older. Features also seen on the EKG include Right Atrial Enlargement, PR prolongation and advanced AV block. When you suspect a patient has an ASD based on the findings of an incomplete Right Bundle Branch Block with a rSr' or rSR' the next thing you should do is examine the frontal plane QRS. The frontal plane QRS is the most helpful clue to help you differentiate Secundum ASD from Primum ASD. In Primum defects left axis deviation is seen in most patients with an axis of > -30 degrees and very few patients have right axis deviation. In contrast Secundum defects have an axis between 0 degrees and 180 degrees with most cases to the right of 100 degrees.

In the ECG above, you can see an example of the rSR' pattern in V1 with a R' greater than S with T wave inversion which is commonly seen in volume overload Right Ventricular Hypertrophy.

As Lutembacher's syndrome is known for ASD and MS, most of the symptoms experienced will be associated with ASD and MS. For most people, they will remain asymptomatic (experience no symptoms) but when symptoms are shown, they are due mainly to ASD and will vary depending on the size of the hole in the atria. If the patient has a large ASD, pulmonary congestion (blood or fluid buildup in the lungs) will happen later but if the patient has a small ASD, symptoms will appear early in the disorder. In general, unless the ASD and mitral stenosis causing Lutembacher's syndrome is severe, symptoms may not appear until the second and third decade of the patient's life. As many of the symptoms are asymptomic and may not appear until later in life, the duration or frequency of the symptoms varies. For symptoms such as palipitations, ventricular overload, heart failure, and pulmonary congenstion, these symptoms may be sudden and not that frequent as they are very severe symptoms. For symptoms such as loud mitral S1, pulmonary S2, mid-diastolic murmur, fatigue, reduced exercise tolerance, weight gain, ankle edema, and right upper quadrant pain, and ascities, these symptoms may be less frequent and severe; their duration may be only a few seconds, minutes, or even months.

d-TGA is often accompanied by other heart defects, the most common type being shunts such as atrial septal defect (ASD) including patent foramen ovale (PFO), ventricular septal defect (VSD), and patent ductus arteriosus (PDA). Stenosis of valves or vessels may also be present.

When no other heart defects are present it is called 'simple' d-TGA; when other defects are present it is called 'complex' d-TGA.

Although it may seem counterintuitive, complex d-TGA presents better chance of survival and less developmental risks than simple d-TGA, as well as usually requiring fewer invasive palliative procedures. This is because the left-to-right and bidirectional shunting caused by the defects common to complex d-TGA allow a higher amount of oxygen-rich blood to enter the systemic circulation. However, complex d-TGA may cause a very slight increase to length and risk of the corrective surgery, as most or all other heart defects will normally be repaired at the same time, and the heart becomes "irritated" the more it is manipulated.

Coronary artery anomalies (or malformation of coronary vessels) are congenital abnormalities in the coronary anatomy of the heart. By definition, these abnormalities are variants of anatomy occurring in less than 1% of the general population. They are often found in combination with other congenital heart defects. Many coronary anomalies don't cause symptoms and are recognized only at the time of autopsy.

They can be associated with sudden death. The real risk of death or the best way to treat these patients is not yet known. The Congenital Heart Surgeons' Society has started a long-term ongoing study called anomalous aortic origin of a coronary artery (AAOCA) to identify the best way to treat this defect.

CXR : decreased pulmonary blood flow and oligemic lung field

ECG : left axis deviation

Anomalous aortic origin of a coronary artery (AAOCA) from the inappropriate sinus of Valsalva with an interarterial, intraconal, or intramural course is a rare heart defect associated with an increased risk of sudden death in children.

This type of aneurysm is typically congenital and may be associated with heart defects. It is sometimes associated with Marfan syndrome or Loeys–Dietz syndrome, but may also result from Ehlers–Danlos syndrome, bicuspid aortic valve, atherosclerosis, hypoplastic left heart syndrome, syphilis, cystic medial necrosis, chest injury, or infective endocarditis.

Signs and symptoms of ischemic cardiomyopathy include sudden fatigue, shortness of breath, dizziness and palpitations.

If unruptured, this type of aneurysm may be asymptomatic and therefore go undetected until symptoms appear or medical imaging is performed for other reasons. A ruptured aneurysm typically leads to an aortocardiac shunt and progressively worsening heart failure.

An aneurysm of the aortic sinus may rupture due to infective endocarditis involving the aortic wall and tertiary-stage syphilis.

The manifestations appear depending on the site where the sinus has ruptured. For example, if the sinus ruptures in a low pressure area like the right atrium or right ventricle then a continuous type of murmur is heard. The murmur is located in the left parasternal region mainly confined to the lower sternum. It is also accompanied by a superficial thrill. A ruptured Sinus of Valsalva abscess represents a surgical emergency.

In 2009, The Congenital Heart Surgeons' Society (CHSS) established a North American Registry in order to study a large multi-institutional cohort of patients with AAOCA. This initiative is intended to generate new knowledge concerning the natural history of AAOCA, to describe the outcomes of surgical intervention versus observation in children and young adults with AAOCA, and to generate evidence to support risk stratification among patients with AAOCA and eventually suggest evidence-based guidelines for management.

Tricuspid atresia is a form of congenital heart disease whereby there is a complete absence of the tricuspid valve. Therefore, there is an absence of right atrioventricular connection. This leads to a hypoplastic (undersized) or absent right ventricle.

This defect is contracted during prenatal development, when the heart does not finish developing. It causes the heart to be unable to properly oxygenate the rest of the blood in the body. Because of this, the body does not have enough oxygen to live, so other defects must occur to maintain blood flow.

Because of the lack of an A-V connection, an atrial septal defect (ASD) must be present to fill the left ventricle with blood. Also, since there is a lack of a right ventricle there must be a way to pump blood into the pulmonary arteries, and this is accomplished by a ventricular septal defect (VSD).

The causes of Tricupsid atresia are unknown.

An atrial septal defect (ASD) and a ventricular septal defect (VSD) must both be present to maintain blood flow-from the right atrium, the blood must flow through the ASD to the left atrium to the left ventricle and through the VSD to the right ventricle to allow access to the lungs

Cor triatriatum (or triatrial heart) is a congenital heart defect where the left atrium (cor triatriatum sinistrum) or right atrium (cor triatriatum dextrum) is subdivided by a thin membrane, resulting in three atrial chambers (hence the name).

Cor triatriatum represents 0.1% of all congenital cardiac malformations and may be associated with other cardiac defects in as many as 50% of cases. The membrane may be complete or may contain one or more fenestrations of varying size.

Cor triatrium sinistrum is more common. In this defect there is typically a proximal chamber that receives the pulmonic veins and a distal (true) chamber located more anteriorly where it empties into the mitral valve. The membrane that separates the atrium into two parts varies significantly in size and shape. It may appear similar to a diaphragm or be funnel-shaped, bandlike, entirely intact (imperforate) or contain one or more openings (fenestrations) ranging from small, restrictive-type to large and widely open.

In the pediatric population, this anomaly may be associated with major congenital cardiac lesions such as tetralogy of Fallot, double outlet right ventricle, coarctation of the aorta, partial anomalous pulmonary venous connection, persistent left superior vena cava with unroofed coronary sinus, ventricular septal defect, atrioventricular septal (endocardial cushion) defect, and common atrioventricular canal. Rarely, asplenia or polysplenia has been reported in these patients.

In the adult, cor triatriatum is frequently an isolated finding.

Cor triatriatum dextrum is extremely rare and results from the complete persistence of the right sinus valve of the embryonic heart. The membrane divides the right atrium into a proximal (upper) and a distal (lower) chamber. The upper chamber receives the venous blood from both vena cavae and the lower chamber is in contact with the tricuspid valve and the right atrial appendage.

The natural history of this defect depends on the size of the communicating orifice between the upper and lower atrial chambers. If the communicating orifice is small, the patient is critically ill and may succumb at a young age (usually during infancy) to congestive heart failure and pulmonary edema. If the connection is larger, patients may present in childhood or young adulthood with a clinical picture similar to that of mitral stenosis. Cor triatriatum may also be an incidental finding when it is nonobstructive.

The disorder can be treated surgically by removing the membrane dividing the atrium.

Ischemic cardiomyopathy is a type of cardiomyopathy caused by a narrowing of the coronary arteries which supply blood to the heart. Typically, patients with ischemic cardiomyopathy have a history of acute myocardial infarction, however, it may occur in patients with coronary artery disease, but without a past history of acute myocardial infarction. This cardiomyopathy is one of the leading causes of sudden cardiac death.

This condition can cause complications such as vasospasm, angina pectoris, arrhythmia, ventricular tachycardia. Additionally many patients express discomfort in specific positions, (i.e. lying on the left side for a prolonged period of time).

A myocardial bridge occurs when one of the coronary arteries tunnels through the myocardium rather than resting on top of it. Typically, the arteries rest on top of the heart muscle and feed blood down into smaller vessels that populate throughout the myocardium. But if the muscle grows around one of the larger arteries, then a myocardial bridge is formed. As the heart squeezes to pump blood, the muscle exerts pressure across the bridge and constricts the artery. This defect is present from birth. It can lead to uncomfortable, powerful heartbeats and angina. The incidence of the condition in the general population is estimated at 5% based on autopsy findings, but significance when found in association with other cardiac conditions is unknown.

The condition is diagnosed on a scale based on what percentage of obstruction occurs. If there is less than 50% blockage, then the condition is probably benign. Blockage over 70% usually causes some pain. Small amounts of myocardial bridging often are undetectable, as the blood usually flows through the coronary while the heart is relaxing in diastole.

Even though many types of sick sinus syndrome produce no symptoms, a person may present with one or more of the following signs and symptoms:

- Stokes-Adams attacks – fainting due to asystole or ventricular fibrillation

- Dizziness or light-headedness

- Palpitations

- Chest pain or angina

- Shortness of breath

- Fatigue

- Headache

- Nausea

Third-degree atrioventricular block (AV block), also known as complete heart block, is a medical condition in which the impulse generated in the sinoatrial node (SA node) in the atrium of the heart does not propagate to the ventricles.

Because the impulse is blocked, an accessory pacemaker in the lower chambers will typically activate the ventricles. This is known as an "escape rhythm". Since this accessory pacemaker also activates independently of the impulse generated at the SA node, two independent rhythms can be noted on the electrocardiogram (ECG).

- The P waves with a regular P-to-P interval (in other words, a sinus rhythm) represent the first rhythm.

- The QRS complexes with a regular R-to-R interval represent the second rhythm. The PR interval will be variable, as the hallmark of complete heart block is lack of any apparent relationship between P waves and QRS complexes.

Patients with third-degree AV block typically experience severe bradycardia (an abnormally-low measured heart rate), hypotension, and at times, hemodynamic instability.

Although there are many signs and symptoms associated with PVCs, PVCs may have no symptoms at all. An isolated PVC is hard to catch without the use of a Holter monitor. PVCs may be perceived as a skipped heart beat, a strong beat, or a feeling of suction in the chest. They may also cause chest pain, a faint feeling, fatigue, or hyperventilation after exercise. Several PVCs in a row becomes a form of ventricular tachycardia (VT), which is a potentially fatal abnormal heart rhythm. Overall it has been seen that the symptom felt most by patients experiencing a PVC is the mere perception of a skipped heartbeat. The more frequently these contractions occur, the more likely there are to be symptoms, despite the fact that these beats have little effect of the pumping action of the heart and therefore cause minimal if any symptoms.

Some other possible signs and symptoms of PVCs:

- Abnormal ECG

- Irregular heart beat

- Dyspnea

- Dizziness

- Feeling your heart beat (palpitations)

- Feeling of occasional, forceful beats

- Increased awareness of your heart beat

- Perception of a skipped heartbeat