CARDIAC VALVE OVERVIEW
The Leaflet Lounge
Kristina Mack MSN-ED, BSN, RN, CCRN-CMC, CV-BC
October 2026
LET'S REVIEW BASIC ANATOMY & PHYSIOLOGY…
Deoxygenated blood comes from the vena cava and empties into the right atrium.
The deoxygenated blood is then pumped from the right atrium and into the right ventricle through the tricuspid valve.
Deoxygenated blood is then pumped from the right ventricle and into the pulmonary arteries through the pulmonic valve to advance into the lungs. Here in the lungs is where the carbon dioxide and oxygen exchange occurs.
Oxygenated blood comes from the pulmonary veins and empties into the left atrium.
The oxygenated blood then moves from the left atrium and into the left ventricle through the mitral valve.
The oxygenated blood is then pumped from the left ventricle into the aorta through the aortic valve to supply blood flow to the rest of the body.
SYSTOLE VS. DIASTOLE:�
THE ATRIA AND VENTRICLES HAVE DIFFERENT TIMES IN THE CARDIAC CYCLE FOR SYSTOLE AND DIASTOLE.
SYSTOLE 🡪 THINK CONTRACTION & PUMPING
DIASTOLE 🡪 THINK RELAXATION & FILLING
WHAT MAKES THE LUB-DUB SOUNDS?�
The LUB-DUB (S1 & S2) sound we hear when auscultating heart sounds is the sound of the valves CLOSING.
LUB correlates with ventricular systole
DUB correlates with ventricular diastole
ATRIOVENTRICULAR AND SEMILUNAR VALVES:
These valves differ in their location, structure, and the phase of the cardiac cycle in which they operate.
Atrioventricular (AV) Valves 🡪
Semilunar Valves 🡪
SYSTOLE | DIASTOLE |
CONTRACTION | RELAXATION |
PUMPING | FILLING |
LUB (S1) | DUB (S2) |
SQUEEZE | DECOMPRESSING |
CLOSURE OF THE ATRIOVENTICULAR VALVES | CLOSURE OF THE SEMILUNAR VALVES |
VS.
VENTRICULAR
LEAFLETS
Valve leaflets are thin and flexible flaps within the heart valves that are composed of fibrous and connective tissue (including collagen and elastin) and covered in endothelial cells to reduce friction.
Their function is to passively open and close in response to pressure changes. When open, they allow forward blood flow. When closed, they prevent backflow of blood to ensure unidirectional blood circulation.
The tricuspid, pulmonic, and aortic valve normally have three leaflets.
The mitral valve normally has two leaflets.
Problems with the leaflets occur due to multiple factors such as aging, congenital abnormalities/ conditions, infection, and underlying conditions such as chronic kidney disease, diabetes, myocardial infarction, radiation therapy, congenital valve defects, and genetic syndromes (Marfan syndrome, Ehlers-Danlos syndrome, and Ebstein anomaly).
Think about it…. The leaflets are made of fibrous and connective tissues!
What syndromes and diseases affect fibrous and connective tissue??
Possible problems
of valve leaflets include:
Atresia 🡪 a severe congenital abnormality, occurring during fetal development, where the valve is missing entirely
Prolapse 🡪 a specific type of regurgitation where the leaflet bulges or becomes flopped backwards; this most commonly occurs with the mitral valve
Regurgitation 🡪 “leaky valve”; leaflets don’t close tightly enough which then allows blood to flow backward in the heart
Stenosis 🡪 leaflets become stiff, thickened, or calcified over time leading to a narrowing of the valve opening causing a forward flow problem
ATRESIA
Aortic Atresia (AA) is a rare congenital heart defect where the aortic valve is absent or severely underdeveloped. Exact cause is unknown but thought to related to genetic and environmental factors during fetal development.
AA is life-threatening and treatment involves surgery to create a new aortic valve, create connection form the left ventricle to the aorta, and to enlarge the left ventricle if it is underdeveloped. AA is more common in males than females.
Symptoms of cyanosis, failure to thrive, cardiac murmur, fatigue, and difficulty breathing will present in the first few days of life.
Due to the blood flow interruption, oxygenated blood flows from the lungs to the left atrium. Because the left ventricle cannot pump into the aorta due to the absent valve, the blood flows through an opening in the septal wall (ASD/ VSD) and into the right side of the heart. The right ventricle then pumps mixed blood into the lungs via the pulmonary artery and then to the rest of the body though the Patent Ductus Arteriosus (PDA).
Pulmonary Atresia (PA) is a congenital heart defect and malformation where the pulmonary valve orifice does not develop or does not form appropriately. This leads to the obstruction of blood flow from the right ventricle and into the lungs.
To survive, the body will use a bypass route called the foramen ovale, or use an ASD, to move blood from the right atrium to the left atrium. Additionally, the PDA is used for gas exchange to occur.
Symptoms of PA include cyanosis, fatigue, difficulty breathing, failure to thrive with poor feeding, and pale, cool, clammy skin.
These patients need surgery to correct the malformation and improve blood flow. Medications are given to keep the temporary pathways open (i.e. PFA, ASD, PDA).
Tricuspid Atresia (TA) is a rare and life-threatening congenital heart defect where the tricuspid valve does not develop properly. This leads to the inability of blood flow to go from the right atrium to the right ventricle.
These patients will have an underdeveloped right ventricle, they may have an underdeveloped pulmonary artery, and these patients will have low oxygen levels.
Instead of blood flowing from the right atrium into the right ventricle, it flows from the right atria through an atrial septal defect (ASD) into the left atrium. Some forms of TA can present without patent ductus arteriosus (PDA), but it is less common and life-threatening.
Medication is given to keep the PDA from closing so that some blood flow can move from the aorta to the pulmonary artery for gas exchange to occur. Normally after birth, the ASD and PDA close.
Mitral Atresia (MA) is a rare congenital heart defect where the mitral valve does not develop properly. This valve will be blocked or absent leading to prevention of oxygenated blood to flow from the left atrium and into the left ventricle. This creates an underdeveloped and small (hypoplastic) left ventricle.
MA is often associated with other heart defects such as hypoplastic left heart syndrome, coarctation of the aorta, and transposition of the great arteries.
Symptoms include cyanosis, shortness of breath, heart murmur, failure to thrive, and poor feeding. Treatment involves surgery to create a pathway for oxygenated blood to flow from the left atrium and into the left ventricle.
An ASD, such as PFO, may be present to allow blood flow from the left atrium and into the right atrium and a PDA for blood to reach the rest of the body.
Hypoplastic Left Heart Syndrome (HLHS) is a rare but severe congenital heart defect. It affects the left ventricle, mitral valve, aortic valve, and ascending aorta.
In HLHS, the left side of the heart does not appropriately form during pregnancy which leads to ineffective pumping of blood from the left side to the rest of the body.
PROLAPSE
Tricuspid Valve Prolapse (TVP) 🡪 Improper closure of the valve leads to backward flow of blood from the RV into the RA. It can be caused by myocardial infarction, congenital defects, rheumatic heart disease, or be idiopathic. Most cases are benign and asymptomatic. Severe cases can lead to right-sided heart failure and require repair/ replacement via open-heart surgery or transcatheter approach.
Pulmonic Valve Prolapse (PVP) 🡪 Improper closure of the valve leads to backward flow of blood from the lungs into the RV. PVP is most associated with Pulmonary Hypertension. Left ventricular heart failure and COPD are also linked to PVP. It can also be due to congenital heart defects (i.e., tetralogy of Fallot), myocardial infarction, Lupus, and bacterial endocarditis. Mild cases often require no treatment. Increased severity of symptoms may require surgical repair/ replacement via open-heart surgery or transcatheter approach.
Mitral Valve Prolapse (MVP) 🡪 This is the most common valve prolapse. The mitral valve’s flaps bulge back into the left atrium and can lead to mitral valve regurgitation but not always. Primary MVP occurs with thinning, scarring, or thickening of the supporting tissue of the leaflets. Secondary MVP is linked to conditions causing damage to the surroundings structures as in MI, hypertrophic cardiomyopathy, and rheumatic heart disease. Most patients do not require treatment, but open-heart surgery or a transcatheter procedure for valve repair/ replacement may be necessary in severe cases.
Aortic Valve Prolapse 🡪 This is an uncommon condition where the valve leaflets are weakened, unhinged, or enlarged causing them to bulge backward - leading to improper valve closure. Patients may experience shortness of breath, fatigue, weakness, chest pain/ discomfort, and palpitations. Common causes of this condition include bicuspid aortic valve, aortic root disease, connective tissue disorders, and infections (i.e. endocarditis).
NOW LET’S FOCUS ON
STENOSIS
AND
REGURGITATION
OF THE
TRICUSPID, MITRAL, PULMONIC, AND
AORTIC VALVE.
TRICUSPID VALVE
Tricuspid Regurgitation (TR) is a disease causing the valve to not fully close. Because of this leak, blood will flow backward into the right atrium. This can lead to the right heart having to work harder to pump blood to the lungs. The ventricle will enlarge and weaken over time leading to heart failure.
Treatment options include medications, open-heart surgery, and minimally invasive procedures such as transcatheter clip-based repair or valve-in-valve replacement.
Moderate to severe TR can lead to heart failure, atrial fibrillation, organ damage, reduced quality of life, and in some of cases, death.
These patients present with fatigue, shortness of breath, abdominal and lower peripheral swelling, jugular vein distention, and atrial fibrillation.
The relationship between A-Fib and TR is a two-way street. Long-term A-Fib can lead to right atrium enlargement. This enlargement causes the valve to stretch leading to a leaky valve. This is called secondary or functional TR.
Additionally, a patient with long-standing TR can develop A-Fib due to atrial enlargement and remodeling from the increased pressure in the right atrium because of the backflow of blood.
Tricuspid stenosis (TS) is a valvular abnormality that is rare and is characterized by valve narrowing causing a forward flow problem. Tricuspid stenosis is typically classified into three categories: acquired, congenital, and iatrogenic. It may be caused by various reasons such as rheumatic heart disease, systemic lupus erythematosus, carcinoid syndrome, and congenital defects.
Isolated tricuspid stenosis is uncommon and typically occurs with other valvular abnormalities, most frequently mitral valve pathology, as a complication of rheumatic heart disease.
Because there is a forward flow problem, blood volume is increased in the right atrium leading to elevated right atrial pressures, systemic congestion, and reduced right ventricular output.
Just as in tricuspid regurgitation, tricuspid stenosis causes the right heart to work harder to pump blood to the lungs. The ventricle will enlarge and weaken over time leading to heart failure.
These patients will present with symptoms such as fatigue, shortness of breath, exertional dyspnea, and systemic congestion (enlarged liver, ascites, swelling in the lower extremities). Prognosis of the patient is dependent on the underlying cause and severity of ventricular dysfunction.
Treatment includes medications to reduce symptoms and improve blood flow, as well as valve replacement.
�
MITRAL VALVE
Mitral Regurgitation (MR) is a disease causing the valve to not fully close. Other names include mitral insufficiency and mitral incompetence. Because of this leak, blood will flow backward into the left atrium leading to enlargement. This enlargement can cause atrial fibrillation. Other symptoms include shortness of breath, fatigue, weakness, and peripheral edema.
Primary MR is an issue in the valve itself. Secondary MR is caused by changes to the muscle such as those caused by coronary artery disease, cardiomyopathy, and myocardial infarction. Other causes include tissue damage and rheumatic fever.
When left untreated, patients may develop atrial fibrillation, heart failure, and pulmonary hypertension. Treatment options include medications to lower blood pressure, removed excess fluid, and manage arrhythmias. Severe cases may be treated with open-heart surgery using ring annuloplasty, valve leaflet repair, and/or incorporation of artificial chords. Moderate to severe cases may be treated with a minimally-invasive transcatheter procedure such as clip-based repair (TEER/ MitraClip) or valve-in-valve replacement (TMVR).
Mitral Stenosis (MS) is narrowing of the mitral valve causing restriction of blood flow from the left atrium into the left ventricle. This is a forward flow problem.
Patients usually experience symptoms of shortness of breath, fatigue, peripheral edema, palpitations, and respiratory complications.
It is most commonly caused by rheumatic fever. It can also be caused by heavy calcium buildup around the valve that occurs over time and radiation or congenital defects.
Treatment includes medications such as diuretics, beta-blockers or calcium channel blockers, and anti-coagulants. Diuretics reduce the fluid buildup in the lungs. Beta-blockers or calcium channel blockers are used to reduce the heart rate. Blood thinners are given to prevent blood clots and stroke because.
Patients may also be treated with a catheter-based procedure called balloon valvuloplasty to widen the valve without open-heart surgery. Severe cases may be treated with open-heart surgery by repairing the leaflets or replacing the valve itself with a mechanical or biological valve.
AORTIC VALVE
Aortic Regurgitation (AR), also called Aortic Insufficiency, is a condition of the heart where the aortic valve fails to close appropriately which allows the blood to flow backward into the left ventricle. Because of this failure, the heart must work harder.
Patient usually experience symptoms such as dyspnea, chest pain, syncope, palpitations, fatigue, cough, and peripheral edema. Typically, these symptoms develop slowly and can progress silently for years before causing symptoms.
AR is most caused by valve decline due to aging. Other causes include congenital defects, rheumatic heart disease, hypertension, endocarditis, thoracic aortic aneurysm, aortic dissection, and thoracic trauma.
For mild cases, treatment is managed with medications such as beta-blockers and ACE inhibitors. These medications work to lower blood pressure, decrease workload of the heart and prevent remodeling. Severe cases are treated with surgical repair or replacement.
TAVR has been used off-label to treat AR, but this increases risk of valve migration and leakage because of the lack of calcium for the device to attach to.
Aortic Stenosis (AS) is a condition defined by narrowing of the aortic valve, primarily caused by calcium buildup, that restricts blood flow from the left ventricle to the aorta. Because of this, there is a forward flow problem. The most common cause is calcific/ degenerative due to aging. Other causes include congenital defects, rheumatic fever, or radiation-induced.
When left untreated, severe pressure gradient will eventually impair stroke volume causing a decrease in cardiac output. The body attempts to compensate by thickening the left ventricular wall (concentric hypertrophy) which leads to diastolic stiffness (reduction of chamber compliance) and increases the filling pressure.
Symptoms are often gradual. Severe narrowing leads to symptoms of chest pain, dyspnea, dizziness, syncope, fatigue, weakness, exercise intolerance, and palpitations.
The treatment is dependent on severity. Mild to moderate cases are regularly monitored. There are no available medications to reverse the narrowed valve, but patients may be put on medications to manage their symptoms, control their blood pressure, and reduce the risk of heart failure.
Severe and symptomatic AS is treated with open-heart surgical aortic valve replacement (SAVR) or transcatheter aortic valve replacement (TAVR).
AS may be classified by the location of the narrowing:
AS is also classified by severity:
PULMONIC VALVE
Pulmonic Regurgitation (PR) is a condition where the valve fails to properly close. This failure leads to oxygen-poor blood to leak backward from the pulmonary artery into the right ventricle.
The most common cause of PR in adults is pulmonary hypertension, but it can also be caused by congenital heart defects (i.e., Tetralogy of Fallot), rheumatic heart disease, infective endocarditis, and carcinoid syndrome (rare condition triggered by neuroendocrine tumors secreting excess hormones, primarily serotonin, directly into the bloodstream.
In most cases, this condition is asymptomatic, but moderate to severe regurgitation can lead to dyspnea, fatigue, chest pain, palpitations, syncope, and peripheral edema.
Treatment typically focuses on managing the underlying causes. Medications are given to lower pulmonary artery pressure (vasodilators like phosphodiesterase-5 inhibitors, endothelin receptor antagonists, prostacyclins, and calcium channel blockers). Supportive medications such as diuretics and blood thinners may be prescribed as well. Severe and symptomatic cases may require surgery to repair or replace the valve.
Pulmonic Stenosis (PS) is narrowing of the pulmonic valve causing right ventricular thickening and increased workload of the heart.
Symptoms are dependent on the severity of the narrowing. Mild cases are typically benign. With moderate to severe narrowing, patients may present with dyspnea, fatigue, decreased exertion tolerance, palpitations, peripheral edema, and cyanosis.
The different types of PS are valvular, sub-valvular, supravalvular, and acquired. Valvular is the most common form and defined as narrowing at the valve itself. It is often due to thickened or fused leaflets. Sub-valvular is narrowing just below the valve in the right ventricle, and supravalvular is just above in the pulmonary artery. Acquired PS is rare but can develop later in life due to specific conditions such as rheumatic fever and carcinoid syndrome.
Treatment includes balloon valvuloplasty, surgical valvotomy, and valve replacement with a biological or mechanical valve. With balloon valvuloplasty a catheter directs a small ballon to inflate and stretch the narrowed valve. Surgical valvotomy is an open-heart surgical procedure where the surgeon cuts the fused valve leaflets, therefore widening the opening.
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