Medical Glossary.

An advanced form of echocardiography that creates three-dimensional images of the heart in real time. Particularly valuable for assessing mitral valve anatomy before repair and guiding transcatheter structural interventions.

An aneurysm in the section of the aorta that passes through the abdomen, usually below the renal arteries. More common in men over 65 and smokers. Can be treated with open surgical repair or endovascular stent grafting (EVAR).

Clinical practice guidelines jointly issued by the American College of Cardiology and the American Heart Association. These evidence-based recommendations standardize the diagnosis and treatment of cardiovascular conditions across the United States.

Angiotensin-Converting Enzyme inhibitor. A class of medications that relax blood vessels and reduce blood pressure by blocking the formation of angiotensin II. Cornerstone therapy for heart failure and after heart attacks.

A 24-hour test using a portable cuff that takes blood pressure readings at regular intervals during daily activities and sleep. Provides a more accurate picture of blood pressure control than single office measurements.

A potent antiarrhythmic medication used to treat and prevent various heart rhythm disorders, particularly atrial fibrillation and ventricular tachycardia. Effective but requires monitoring for potential side effects on the thyroid, lungs, and liver.

A surgical technique used during valve repair in which a ring or band is sewn around the valve annulus (the ring of tissue supporting the valve) to restore its normal shape and improve leaflet coaptation.

A medication that reduces the blood's ability to form clots. Commonly prescribed after mechanical valve replacement and for atrial fibrillation. Examples include warfarin, apixaban (Eliquis), and rivaroxaban (Xarelto).

The ongoing monitoring and adjustment of blood-thinning medications after surgery. Patients with mechanical valves require lifelong warfarin management with regular INR testing. Bridging therapy may be needed for procedures.

Medications that prevent blood platelets from clumping together to form clots. Aspirin and clopidogrel (Plavix) are the most common. Essential after coronary stent placement and often used after bypass surgery.

The largest artery in the body, originating from the left ventricle and distributing oxygenated blood to all parts of the body. Divided into the ascending aorta, aortic arch, descending thoracic aorta, and abdominal aorta.

An abnormal bulging or dilation of the aorta, the body's largest artery. Can occur in the thoracic (chest) or abdominal sections. If left untreated, an aneurysm can rupture, which is a life-threatening emergency.

A complex surgical procedure to replace the curved portion of the aorta that gives rise to the brain and arm arteries. Often performed under deep hypothermic circulatory arrest. One of the most technically demanding cardiac operations.

A tear in the inner layer of the aortic wall that allows blood to flow between the layers, creating a false channel. Type A dissections (involving the ascending aorta) require emergency surgery. A life-threatening cardiovascular emergency.

The section of the aorta closest to the heart, encompassing the aortic valve, sinuses of Valsalva, and coronary artery origins. Dilation of the aortic root can lead to aortic regurgitation and may require surgical intervention.

Narrowing of the aortic valve that restricts blood flow from the heart to the body. The most common valvular heart disease in adults over 65, often caused by age-related calcium buildup on the valve leaflets.

The valve between the left ventricle and the aorta that normally has three leaflets (cusps). Opens to allow blood to flow into the aorta during contraction and closes to prevent backflow. The most commonly replaced heart valve.

Angiotensin Receptor Blocker. A class of blood pressure medications that block the action of angiotensin II at its receptor. Often used as an alternative to ACE inhibitors in patients who experience cough as a side effect.

The gradual buildup of fatty deposits (plaque) inside artery walls. Over decades, plaque narrows the arteries and restricts blood flow. When it occurs in the coronary arteries, it is called coronary artery disease.

The most common heart rhythm disorder, in which the upper chambers (atria) beat irregularly and often rapidly. Increases the risk of stroke by up to five times. May be treated with medications, ablation, or the Maze procedure.

A heart rhythm disorder similar to atrial fibrillation but with a more organized, regular rapid rhythm in the atria. Often treated with catheter ablation, which has a high success rate for typical flutter.

A complex cardiac surgery that replaces the aortic root, aortic valve, and ascending aorta with a composite graft containing a mechanical or bioprosthetic valve. The coronary arteries are reimplanted into the new graft.

A class of medications that slow the heart rate and lower blood pressure by blocking the effects of adrenaline. Widely used after heart attacks, in heart failure, for arrhythmias, and to protect the aorta in Marfan syndrome.

A congenital heart defect in which the aortic valve has two leaflets instead of the normal three. Present in roughly 1-2% of the population, it can lead to aortic stenosis, regurgitation, or aortic aneurysm over time.

A replacement heart valve made from animal tissue (usually pig or cow). Bioprosthetic valves typically last 10 to 20 years and do not require lifelong blood-thinning medication, making them a common choice for older patients.

The administration of donated blood products during or after cardiac surgery. Needed when blood loss exceeds the body's ability to compensate. Many cardiac surgical programs employ blood conservation strategies to minimize transfusion.

B-type Natriuretic Peptide. A blood test used to help diagnose and monitor heart failure. BNP is a hormone released by the heart when it is under stress from volume overload. Elevated levels suggest the heart is struggling.

An abnormally slow heart rate, typically below 60 beats per minute. Can cause dizziness, fatigue, and fainting. When symptomatic, a pacemaker is usually required to maintain an adequate heart rate.

Coronary Artery Bypass Grafting. An open-heart surgery that creates new routes for blood to flow around blocked coronary arteries. Surgeons use arteries or veins from other parts of the body as grafts to bypass the blockages.

A CT scan that measures the amount of calcified plaque in the coronary arteries. Expressed as an Agatston score. A score of zero suggests very low risk, while scores above 400 indicate significant coronary atherosclerosis.

The placement of tubes (cannulae) into blood vessels or the heart to connect the patient to the cardiopulmonary bypass machine. Sites include the aorta, right atrium, femoral artery, and femoral vein.

The sudden cessation of effective heart pumping, leading to loss of consciousness and death within minutes without treatment. Different from a heart attack. Survival depends on immediate CPR and defibrillation.

A procedure in which a thin tube (catheter) is threaded through a blood vessel to the heart. Allows direct measurement of pressures inside the heart and injection of contrast dye to visualize the coronary arteries (coronary angiography).

Computed Tomography of the heart using rapid, ECG-gated scanning. Provides detailed anatomical images for planning TAVR, evaluating the aorta, and measuring coronary calcium. Increasingly used for preoperative surgical planning.

Magnetic Resonance Imaging of the heart. Uses magnetic fields and radio waves to create detailed images of heart structure and function. The gold standard for measuring ejection fraction and detecting scar tissue (fibrosis) in the heart muscle.

The volume of blood the heart pumps per minute, calculated as heart rate multiplied by stroke volume. A normal cardiac output is about 4 to 8 liters per minute. Reduced cardiac output is the hallmark of heart failure.

A medically supervised program of exercise, education, and counseling designed to help patients recover after heart surgery, heart attack, or heart failure. Typically lasts 12 weeks and significantly improves outcomes and quality of life.

A specialized pacemaker (CRT or BiV pacer) that coordinates the contractions of the left and right ventricles in patients with heart failure and electrical conduction delays. Can improve symptoms and ejection fraction.

A life-threatening condition in which the heart suddenly cannot pump enough blood to meet the body's needs, usually following a massive heart attack. Requires emergency treatment with medications, mechanical support devices, or surgery.

A disease of the heart muscle that makes it harder for the heart to pump blood. Types include dilated (enlarged, weakened), hypertrophic (thickened), and restrictive (stiff). Can be inherited or acquired.

A technique that temporarily takes over the function of the heart and lungs during surgery, allowing the surgeon to operate on a still, bloodless heart. Uses a heart-lung machine to oxygenate and circulate blood.

A specialized exercise test (CPET) that measures oxygen consumption and carbon dioxide production during exertion. Provides an objective measure of functional capacity and helps determine candidacy for heart surgery or transplant.

The surgical specialty focused on diseases of the heart, lungs, esophagus, and other organs within the chest. Cardiothoracic surgeons perform CABG, valve surgery, aortic surgery, heart transplants, and lung cancer operations.

A procedure to restore a normal heart rhythm by delivering a controlled electric shock to the heart (electrical cardioversion) or using medications (pharmacological cardioversion). Commonly used for atrial fibrillation and atrial flutter.

A minimally invasive procedure that uses heat (radiofrequency) or cold (cryoablation) energy delivered through a catheter to destroy small areas of heart tissue causing abnormal electrical signals. Commonly used to treat atrial fibrillation.

A scoring system used to estimate the risk of stroke in patients with atrial fibrillation. Incorporates factors such as age, sex, heart failure, hypertension, diabetes, and prior stroke. Guides decisions about anticoagulation therapy.

A flexible tube inserted through the chest wall after heart surgery to drain blood, fluid, and air from around the heart and lungs. Typically removed within one to three days after surgery when drainage decreases.

Thin, cord-like tendons that connect the mitral and tricuspid valve leaflets to the papillary muscles of the ventricles. They prevent the valve leaflets from prolapsing backward during contraction. Rupture can cause acute valve regurgitation.

A complete blockage of a coronary artery that has been present for at least three months. These are among the most challenging lesions for interventional cardiologists and may require specialized PCI techniques or CABG.

One of the three major coronary arteries, branching from the left main coronary artery and supplying blood to the lateral and posterior walls of the left ventricle. Blockages are treated with PCI or bypassed during CABG.

Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation trial. Demonstrated significant benefit of MitraClip over medical therapy alone in select heart failure patients.

A personalized model of cardiovascular care that provides patients with direct access to top specialists, extended consultations, and coordinated second opinions. Focuses on giving patients the time and attention needed for complex cardiac decisions.

An additional surgical procedure performed at the same time as the primary operation. For example, a Maze procedure for atrial fibrillation performed during a mitral valve repair. Reduces the need for a separate surgery.

Heart defects present from birth, ranging from simple holes between heart chambers to complex malformations. Advances in surgery have dramatically improved survival, and many patients now live into adulthood requiring ongoing cardiac care.

An X-ray imaging procedure that uses contrast dye injected through a catheter to visualize the inside of coronary arteries and identify blockages. The gold standard for diagnosing coronary artery disease.

The network of blood vessels on the surface of the heart that supply the heart muscle with oxygen-rich blood. The three main coronary arteries are the LAD, circumflex, and right coronary artery.

A condition caused by the buildup of plaque (atherosclerosis) inside the coronary arteries, which supply blood to the heart muscle. The leading cause of heart attacks and the most common reason for coronary bypass surgery.

A surgical technique used during CABG to remove atherosclerotic plaque from within a severely diseased coronary artery. Performed when the artery is too diffusely diseased for a standard bypass graft anastomosis.

A noninvasive imaging test that uses a CT scanner and contrast dye to create detailed 3D images of the heart and blood vessels. Can evaluate coronary arteries, aortic disease, and cardiac anatomy without catheterization.

A valve-sparing aortic root replacement surgery that replaces the diseased aorta while preserving the patient's own aortic valve. Avoids the need for lifelong anticoagulation. Particularly beneficial for younger patients.

A common but often underrecognized condition affecting up to 25 percent of patients after cardiac surgery. Symptoms include persistent sadness, loss of interest, fatigue, and sleep disturbances. Screening and early treatment improve outcomes.

The use of a left ventricular assist device (LVAD) as a permanent treatment for end-stage heart failure in patients who are not candidates for heart transplant. The device remains implanted for the rest of the patient's life.

A condition in which the left ventricle becomes enlarged and weakened, reducing its ability to pump blood effectively. The most common type of cardiomyopathy and a leading cause of heart failure and heart transplant.

A medication that helps the kidneys remove excess fluid and salt from the body through urine. Used to treat fluid retention (edema) in heart failure. Furosemide (Lasix) is the most commonly prescribed loop diuretic.

Direct Oral Anticoagulant. A newer class of blood thinners including apixaban (Eliquis), rivaroxaban (Xarelto), dabigatran (Pradaxa), and edoxaban (Savaysa). Do not require routine blood monitoring. Not approved for mechanical heart valves.

A component of echocardiography that measures the speed and direction of blood flow through the heart and blood vessels. Color Doppler shows flow direction, while spectral Doppler measures velocity and calculates pressure gradients.

Limitations on operating a motor vehicle following cardiac surgery, typically lasting four to eight weeks after sternotomy. Restrictions exist because of sternal precautions, potential medication side effects, and reaction time concerns.

A small metal mesh tube coated with medication that is placed inside a coronary artery during PCI. The drug slowly releases over time to prevent scar tissue from regrowing and re-narrowing the artery (restenosis).

The combination of aspirin plus a P2Y12 inhibitor (such as clopidogrel, prasugrel, or ticagrelor). Required for a period after coronary stenting to prevent stent thrombosis. Duration varies based on stent type and patient risk.

An ultrasound of the heart that uses sound waves to create real-time images of the heart's chambers, valves, and blood flow. The most commonly used imaging test for evaluating heart valve disease and heart function.

Extracorporeal Membrane Oxygenation. A form of life support that takes over the work of the heart and lungs by pumping blood through an artificial lung outside the body. Used in severe cardiac or respiratory failure as a temporary measure.

A measurement of how much blood the left ventricle pumps out with each contraction, expressed as a percentage. A normal ejection fraction is 55-70%. Below 40% is considered reduced and indicates weakened heart muscle function.

A test (ECG or EKG) that records the electrical activity of the heart using electrodes placed on the skin. Takes only a few minutes and can detect arrhythmias, heart attacks, and other cardiac conditions.

A test in which catheters with electrodes are placed inside the heart to map its electrical system. Identifies the origin and mechanism of arrhythmias and is often performed immediately before catheter ablation.

An infection of the inner lining of the heart chambers and valves, usually caused by bacteria entering the bloodstream. Can destroy valve tissue and may require emergency surgery to replace the infected valve.

The smooth inner lining of the heart chambers and valves. Infection of the endocardium (endocarditis) can damage heart valves. The endocardium plays a role in regulating heart muscle contraction.

Persistent blood flow outside the stent graft but within the aneurysm sac after an endovascular aortic repair. Classified into types I through V depending on the source. Some endoleaks require reintervention.

European System for Cardiac Operative Risk Evaluation. A scoring system that predicts the risk of death after heart surgery. EuroSCORE II is the current version, incorporating patient, cardiac, and operative factors.

Endovascular Aneurysm Repair. A minimally invasive procedure to treat abdominal aortic aneurysms using a stent graft placed through small incisions in the groin. Offers faster recovery than open surgical repair.

The practice of making clinical decisions based on the best available research evidence, combined with clinical expertise and patient values. The foundation of modern cardiovascular guidelines and Heart Team decision-making.

A series of clinical trials evaluating the Medtronic CoreValve/Evolut TAVR system. The Evolut Low Risk trial demonstrated TAVR was noninferior to surgery even in low-risk patients, further expanding the indications for transcatheter valve replacement.

Evaluation of XIENCE versus Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization trial. Compared PCI with drug-eluting stents to CABG for left main coronary disease. Results continue to inform Heart Team decisions.

Real-time continuous X-ray imaging used during cardiac catheterization, PCI, TAVR, and device implantation. Allows the interventionalist to see catheters, wires, and devices as they are positioned inside the heart and blood vessels.

Scheduled post-surgical visits with the cardiac surgeon and cardiologist to monitor healing, adjust medications, review imaging, and manage any complications. Typically at 2 weeks, 6 weeks, 3 months, and annually after cardiac surgery.

A pressure-based measurement (FFR) taken during cardiac catheterization to determine whether a coronary artery blockage is actually limiting blood flow. An FFR value of 0.80 or less indicates a significant blockage that would benefit from treatment.

An evaluation of a patient's physiological reserve and vulnerability to stress. Measures grip strength, walking speed, nutritional status, and cognitive function. Frailty is a stronger predictor of surgical outcomes than age alone.

Future Revascularization Evaluation in Patients with Diabetes Mellitus: Optimal Management of Multivessel Disease trial. Demonstrated that CABG was superior to PCI in diabetic patients with multivessel coronary artery disease.

A scoring system that estimates the risk of major bleeding in patients taking anticoagulants. Considers factors like hypertension, abnormal kidney/liver function, prior stroke, and alcohol use. Helps balance bleeding versus stroke risk.

A delay or complete interruption in the electrical signals traveling from the atria to the ventricles. Classified as first, second, or third degree. Third-degree (complete) heart block usually requires a permanent pacemaker.

A chronic condition in which the heart cannot pump blood efficiently enough to meet the body's needs. Can affect the left side, right side, or both. Symptoms include fatigue, shortness of breath, and fluid retention.

A multidisciplinary group of cardiac surgeons, interventional cardiologists, imaging specialists, and other clinicians who collaborate to determine the optimal treatment strategy for each patient. Recommended by ACC/AHA guidelines for complex cardiac decisions.

A surgical procedure to replace a failing heart with a healthy donor heart. Reserved for patients with end-stage heart failure who have exhausted other treatment options. Requires lifelong immunosuppressive medication.

A surgical procedure that replaces the ascending aorta and the underside (lesser curvature) of the aortic arch. Less extensive than a full arch replacement and commonly performed during Type A dissection repair.

Measurement of blood flow and pressures within the heart and blood vessels. Performed during cardiac catheterization to evaluate valve severity, heart function, and pulmonary pressures. Guides surgical decision-making.

An injectable anticoagulant used during cardiac surgery, catheter procedures, and in hospitals to prevent blood clots. Acts rapidly and can be reversed with protamine. Unfractionated heparin and low-molecular-weight forms are available.

Heart Failure with Preserved Ejection Fraction (EF 50% or greater). Previously called diastolic heart failure. The heart muscle contracts normally but is stiff and cannot relax and fill properly. An increasingly recognized condition.

Heart Failure with Reduced Ejection Fraction (EF 40% or less). Previously called systolic heart failure. The heart muscle is weakened and cannot contract forcefully enough. Treated with medications, devices, or transplant.

A portable device worn continuously for 24 to 48 hours that records the heart's electrical activity. Used to detect intermittent arrhythmias that may not appear on a standard ECG during a brief office visit.

Persistently elevated blood pressure, defined as systolic pressure of 130 mmHg or higher or diastolic pressure of 80 mmHg or higher. A major risk factor for coronary artery disease, heart failure, aortic aneurysm, and stroke.

A genetic condition in which the heart muscle becomes abnormally thick, making it harder for the heart to pump blood. Can obstruct blood flow from the left ventricle (HOCM). A leading cause of sudden cardiac death in young athletes.

A surgical technique in which the patient's body temperature is lowered significantly and blood circulation is temporarily stopped. Provides a bloodless surgical field for complex aortic arch operations, protecting the brain and organs.

Implantable Cardioverter-Defibrillator. A device similar to a pacemaker that can also detect and treat life-threatening fast heart rhythms (ventricular tachycardia or fibrillation) by delivering an electric shock to restore normal rhythm.

The period spent in the Intensive Care Unit immediately after cardiac surgery for close monitoring. Patients are typically on a ventilator initially and have multiple monitoring lines. ICU stay after routine heart surgery averages one to two days.

The process of providing a patient with comprehensive information about a proposed procedure, including risks, benefits, alternatives, and expected outcomes, before obtaining their voluntary agreement to proceed.

International Normalized Ratio. A blood test that measures how long it takes blood to clot, used to monitor patients on warfarin. The target INR range depends on the indication — typically 2.0 to 3.0 for atrial fibrillation and 2.5 to 3.5 for mechanical valves.

A subspecialty of cardiology focused on catheter-based treatments for heart disease. Interventional cardiologists perform PCI, TAVR, MitraClip, and other structural heart procedures using minimally invasive techniques.

A mechanical device inserted through the femoral artery into the aorta that inflates and deflates in sync with the heartbeat. Helps the heart pump more blood and is used to support patients in cardiogenic shock or before surgery.

International Study of Comparative Health Effectiveness with Medical and Invasive Approaches trial. Showed that in patients with stable coronary artery disease, an initial conservative (medication) strategy was comparable to early invasive treatment (PCI or CABG).

Intravascular Ultrasound. A catheter-based imaging technique that uses ultrasound from inside a coronary artery to visualize plaque and vessel wall detail. Helps guide stent placement and assess stent expansion during PCI.

Left Anterior Descending artery. The largest and most important coronary artery, supplying blood to the front and bottom of the left ventricle. Often called the "widow-maker" because a complete blockage can be life-threatening.

A cardiac MRI technique that uses a gadolinium-based contrast agent to identify areas of scar tissue or fibrosis in the heart muscle. Bright areas on the scan indicate damaged tissue. Used to assess viability and diagnose cardiomyopathies.

A procedure to seal off the left atrial appendage, a small pouch in the heart where blood clots commonly form in patients with atrial fibrillation. Devices such as the WATCHMAN can reduce stroke risk without long-term blood thinners.

The upper left chamber of the heart that receives oxygenated blood from the lungs via the pulmonary veins. Blood flows from the left atrium through the mitral valve into the left ventricle. Enlarges in mitral valve disease and atrial fibrillation.

Significant narrowing of the left main coronary artery, which supplies blood to roughly two-thirds of the heart. Considered high-risk because a blockage here threatens a large portion of heart muscle. Often treated with CABG.

The thick-walled, muscular lower left chamber of the heart responsible for pumping oxygenated blood to the entire body through the aorta. The main pumping chamber and the one most commonly affected by heart attacks and heart failure.

Left Internal Mammary Artery. An artery running along the inside of the chest wall that is the gold standard graft for coronary bypass surgery to the LAD. LIMA grafts have the best long-term patency rates of any bypass conduit.

A statistical method used to predict the probability of a specific outcome (such as operative mortality) based on multiple patient variables. The mathematical foundation behind risk calculators like the STS score and EuroSCORE.

Left Ventricular Assist Device. A mechanical pump surgically implanted in the chest to help a weakened left ventricle pump blood to the body. Used as a bridge to heart transplant or as long-term (destination) therapy.

A genetic connective tissue disorder that affects the heart, blood vessels, bones, and eyes. Patients with Marfan syndrome are at high risk for aortic aneurysm and dissection and often require prophylactic aortic surgery.

A surgical treatment for atrial fibrillation performed during open-heart surgery. Creates a pattern of scar tissue (a "maze") in the atria that redirects electrical impulses along a controlled path, restoring normal rhythm.

A replacement heart valve made from durable synthetic materials such as carbon and titanium. Mechanical valves can last a lifetime but require permanent anticoagulation therapy (blood thinners) to prevent blood clots.

A statistical method that combines results from multiple independent studies to produce a more precise estimate of a treatment effect. Provides the highest level of evidence when synthesizing results from several randomized controlled trials.

Heart surgery performed through small incisions between the ribs rather than a full sternotomy. Includes mini-thoracotomy and port-access approaches. Offers reduced pain, shorter hospital stays, and faster recovery.

A catheter-based device used to treat mitral regurgitation without open-heart surgery. A small clip is delivered through a vein and attached to the mitral valve leaflets to reduce backward blood flow.

A condition in which the mitral valve does not close tightly, allowing blood to flow backward into the left atrium during each heartbeat. Can be classified as primary (degenerative) or secondary (functional).

The valve between the left atrium and left ventricle that has two leaflets (anterior and posterior). Prevents blood from flowing backward into the atrium when the ventricle contracts. The most commonly repaired heart valve.

A condition in which the mitral valve leaflets bulge (prolapse) into the left atrium during the heart's contraction. Often benign, but can progress to significant mitral regurgitation requiring surgical repair.

A surgical procedure that fixes a patient's own mitral valve rather than replacing it. Techniques include annuloplasty ring placement, leaflet resection, and chordal reconstruction. Repair is generally preferred over replacement when feasible.

An open-heart procedure to remove a diseased mitral valve and replace it with a mechanical or bioprosthetic valve. Typically performed when repair is not feasible due to the extent of valve damage.

Commonly known as a heart attack. Occurs when blood flow to a section of heart muscle is blocked long enough to cause permanent damage. Symptoms include chest pain, shortness of breath, and sweating. A medical emergency requiring immediate treatment.

The muscular middle layer of the heart wall responsible for contraction and pumping blood. Damage to the myocardium from a heart attack is called myocardial infarction. Heart failure results when the myocardium becomes too weak or stiff.

Nordic-Baltic-British Left Main Revascularisation trial. Compared PCI to CABG for left main coronary disease and found CABG was superior over five years. Along with EXCEL, informs the treatment debate for left main disease.

Non-ST-Elevation Myocardial Infarction. A type of heart attack caused by a partial blockage of a coronary artery. Less immediately life-threatening than a STEMI but still requires urgent evaluation and treatment.

A stress test that uses a small amount of radioactive tracer injected into the bloodstream to create images of blood flow to the heart at rest and during stress. Detects areas of reduced perfusion indicating coronary artery disease.

The New York Heart Association system for classifying heart failure severity based on symptoms during physical activity. Ranges from Class I (no limitation) to Class IV (symptoms at rest). Used to guide treatment decisions and track progression.

Optical Coherence Tomography. A catheter-based imaging technique that uses near-infrared light to create very high-resolution images of the coronary artery wall. Provides ten times the resolution of IVUS for assessing plaque and stent results.

Coronary artery bypass surgery performed on a beating heart without using a heart-lung machine. Special stabilizers hold the area of the heart being operated on still. May reduce complications associated with cardiopulmonary bypass.

Death occurring during or within 30 days of a surgical procedure, or during the same hospitalization. The primary outcome used to compare surgical performance and is reported in national quality databases.

A small battery-powered device implanted under the skin that sends electrical impulses to the heart to maintain a regular heartbeat. Used to treat slow heart rhythms (bradycardia) or certain types of heart block.

Placement of Aortic Transcatheter Valves trial. The landmark series of randomized controlled trials that established TAVR as a treatment for aortic stenosis. PARTNER 1 proved TAVR for inoperable patients; subsequent trials expanded to lower-risk groups.

An approach to healthcare that respects and responds to individual patient preferences, needs, and values. In cardiac surgery, this means ensuring patients understand all treatment options, risks, and expected outcomes before making decisions.

Percutaneous Coronary Intervention, also called coronary angioplasty with stenting. A catheter-based procedure that opens blocked coronary arteries using a balloon and places a stent to keep the artery open.

Surgical removal of part or all of the pericardium, the sac surrounding the heart. Performed for constrictive pericarditis, a condition in which a thickened, scarred pericardium compresses the heart and restricts filling.

A double-layered sac that surrounds and protects the heart, containing a small amount of lubricating fluid. Inflammation (pericarditis) or fluid accumulation (pericardial effusion) in this space can impair heart function.

Positron Emission Tomography of the heart. Uses radioactive tracers to assess myocardial blood flow and viability. Can determine whether areas of weakened heart muscle are still alive and would benefit from revascularization.

An accumulation of fluid in the space between the lungs and chest wall. A common finding after heart surgery that usually resolves on its own. Large effusions may cause shortness of breath and require drainage with a needle or chest tube.

New-onset atrial fibrillation occurring after cardiac surgery, affecting 20 to 40 percent of patients. Usually temporary, peaking on the second or third postoperative day. Managed with rate control, rhythm control, or anticoagulation as needed.

A program of exercise, nutrition optimization, and psychological preparation undertaken before surgery to improve a patient's fitness and resilience. Studies show prehabilitation can reduce complications and speed recovery.

Abnormally high blood pressure in the arteries of the lungs. Can be caused by left heart disease, lung disease, or occur without a known cause (idiopathic). Places strain on the right ventricle and can lead to right heart failure.

The valve between the right ventricle and the pulmonary artery. Controls blood flow from the heart to the lungs. Pulmonary valve disease is less common than aortic or mitral valve disease in adults.

Standardized measures used to evaluate the performance of cardiac surgical programs, including mortality rates, complication rates, readmission rates, and patient satisfaction. Reported to national databases such as the STS National Database.

The gold standard research study design (RCT) in which participants are randomly assigned to a treatment or control group. Minimizes bias and provides the strongest evidence for determining whether a treatment is effective.

Unplanned return to the hospital within 30 days of discharge after cardiac surgery. Common reasons include infection, arrhythmia, fluid retention, and pleural effusions. Reducing readmissions is a major focus of quality improvement programs.

A repeat open-heart operation in a patient who has had prior cardiac surgery. Technically more challenging due to scar tissue (adhesions) from the previous surgery. Requires careful planning to avoid injury during re-entry.

A procedure using a Swan-Ganz catheter to measure pressures in the right side of the heart and pulmonary arteries. Essential for diagnosing pulmonary hypertension and evaluating patients before heart transplant or LVAD.

The lower right chamber of the heart that pumps deoxygenated blood to the lungs through the pulmonary artery. Has thinner walls than the left ventricle and is sensitive to increases in pulmonary pressure.

The process of categorizing patients into risk groups (low, intermediate, high, extreme) based on their likelihood of complications from a procedure. Guides the choice between surgical and catheter-based treatments.

Heart surgery performed using robotic arms controlled by the surgeon from a console, allowing enhanced precision through very small incisions. Used for select mitral valve repairs, CABG, and atrial septal defect closures.

The great saphenous vein runs along the inner leg from the ankle to the groin. It is the most commonly used vein conduit for coronary artery bypass grafting. Can be harvested with open or endoscopic techniques.

A vein harvested from the leg and used as a bypass conduit during CABG surgery. Vein grafts are the most commonly used conduit after the LIMA, though they have lower long-term patency rates than arterial grafts.

Surgical Aortic Valve Replacement. An open-heart procedure to remove a diseased aortic valve and replace it with a mechanical or bioprosthetic valve. Performed through a sternotomy while the patient is on cardiopulmonary bypass.

An evaluation by an independent specialist to confirm a diagnosis or review a proposed treatment plan. Particularly valuable for complex cardiac conditions where different treatment approaches exist. Can provide peace of mind and uncover alternatives.

An open-heart surgery to remove a portion of thickened heart muscle (septum) that obstructs blood flow in patients with hypertrophic obstructive cardiomyopathy (HOCM). Considered the gold standard treatment for symptomatic obstruction.

Sodium-glucose cotransporter 2 inhibitor. Originally developed for diabetes, these medications (empagliflozin, dapagliflozin) have shown significant benefits in heart failure, reducing hospitalizations and cardiovascular death regardless of diabetes status.

A collaborative process in which patients and clinicians make healthcare decisions together, considering the best available evidence alongside the patient's values, preferences, and goals. Central to Heart Team deliberations.

A class of medications that lower LDL ("bad") cholesterol by inhibiting an enzyme in the liver. Statins also stabilize arterial plaque and reduce inflammation. Proven to reduce heart attacks, strokes, and cardiovascular death.

ST-Elevation Myocardial Infarction. The most severe type of heart attack, caused by a complete blockage of a coronary artery. Diagnosed by characteristic changes on an ECG and requires emergency PCI or thrombolytic therapy.

Activity restrictions following a sternotomy to protect the healing breastbone. Typically include avoiding lifting more than 5 to 10 pounds, not pushing or pulling heavy objects, and not driving for 6 to 8 weeks after surgery.

A surgical incision through the breastbone (sternum) to access the heart and major blood vessels. The traditional approach for most open-heart surgeries including CABG and valve replacement. Requires sternal precautions during recovery.

An echocardiogram performed before and immediately after exercise or pharmacological stress. Detects wall motion abnormalities that develop under stress, indicating areas of the heart with inadequate blood supply.

A test that monitors heart function during physical exertion (treadmill or stationary bike) or with medication that simulates exercise. Detects areas of the heart that may not receive adequate blood flow during increased demand.

Sudden interruption of blood supply to the brain, causing brain cell death. Can be ischemic (blocked artery) or hemorrhagic (bleeding). Atrial fibrillation is a leading cause of ischemic stroke, which is why anticoagulation is prescribed.

A category of conditions involving defects or abnormalities in the heart's valves, walls, chambers, or blood vessels. Includes valve disease, septal defects, and hypertrophic cardiomyopathy. Treated with surgery or transcatheter approaches.

The gradual wear and failure of a bioprosthetic heart valve over time. Manifests as increasing stenosis or regurgitation. The main limitation of bioprosthetic valves and a focus of ongoing research into valve durability.

The Society of Thoracic Surgeons risk score. A widely used tool that estimates the risk of mortality and major complications after cardiac surgery based on patient-specific factors. Helps guide surgical decision-making and informed consent.

The Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy registry. Tracks outcomes for all TAVR procedures in the United States. Provides real-world data on safety and efficacy beyond clinical trials.

Unexpected death caused by sudden loss of heart function, usually due to ventricular fibrillation. Different from a heart attack, which is a blockage of blood flow. Survival depends on immediate CPR and defibrillation.

An infection that develops at or near the surgical incision within 30 days of the operation, or within a year if an implant is placed. Deep sternal wound infection (mediastinitis) is a serious complication of open-heart surgery.

The well-established principle that hospitals and surgeons who perform a higher volume of complex procedures tend to achieve better patient outcomes. An important consideration when choosing where to have cardiac surgery.

A scoring system that grades the complexity of coronary artery disease based on angiographic findings. Higher scores indicate more complex disease and generally favor CABG over PCI. Used by Heart Teams to guide treatment decisions.

Synergy between PCI with Taxus and Cardiac Surgery trial. A landmark study comparing PCI to CABG in patients with complex coronary artery disease. Gave rise to the SYNTAX score and demonstrated CABG superiority in high-complexity disease.

Transcatheter Aortic Valve Replacement. A minimally invasive procedure to replace a diseased aortic valve without open-heart surgery. A catheter is threaded through a blood vessel (usually the femoral artery) and a new valve is expanded inside the old one.

Transesophageal Echocardiogram. An ultrasound performed by passing a probe into the esophagus, directly behind the heart. Provides higher-resolution images than TTE, especially of the mitral valve, left atrial appendage, and aorta.

Thoracic Endovascular Aortic Repair. A minimally invasive procedure that uses a stent graft delivered through the femoral artery to repair a thoracic aortic aneurysm or dissection, avoiding open chest surgery.

An aneurysm located in the portion of the aorta within the chest. May involve the aortic root, ascending aorta, aortic arch, or descending aorta. Surgery is typically recommended when the diameter exceeds 5.0 to 5.5 cm.

Backward leaking of blood through the tricuspid valve from the right ventricle into the right atrium. Often secondary to left-sided heart disease or pulmonary hypertension. Severe cases may require surgical repair or replacement.

The valve between the right atrium and right ventricle with three leaflets. Prevents blood from flowing backward into the right atrium. Tricuspid regurgitation is increasingly recognized as a condition requiring intervention.

Significant blockages in all three major coronary arteries: the LAD, circumflex, and right coronary artery. Generally considered an indication for CABG surgery rather than PCI, especially in patients with diabetes.

A protein released into the blood when heart muscle is damaged. The most sensitive and specific blood test for diagnosing a heart attack. Elevated levels indicate myocardial injury and guide treatment decisions.

Transthoracic Echocardiogram. The standard noninvasive ultrasound of the heart performed by placing a probe on the chest wall. Provides images of heart chambers, valves, wall motion, and ejection fraction. The most commonly ordered cardiac imaging study.

An aortic dissection that involves the ascending aorta, regardless of where the tear originates. Classified using the Stanford system. This is a surgical emergency with high mortality if untreated, requiring immediate open-heart repair.

An aortic dissection confined to the descending aorta (beyond the left subclavian artery). Often managed initially with blood pressure control and medication. Complicated cases may require TEVAR or open surgical repair.

A transcatheter procedure used to treat a failing bioprosthetic valve by deploying a new valve inside the deteriorated one, avoiding the need for repeat open-heart surgery. Can be performed for aortic, mitral, or tricuspid positions.

A broad term for conditions in which one or more of the heart's four valves do not function properly. Valves may be stenotic (too narrow), regurgitant (leaky), or both. Affects millions of adults worldwide and increases with age.

A chaotic, disorganized electrical activity in the ventricles that causes the heart to quiver instead of pumping blood. A medical emergency that leads to cardiac arrest and death within minutes if not treated with defibrillation.

The muscular wall separating the left and right ventricles. A hole in this wall (ventricular septal defect) can be congenital or occur after a heart attack. Abnormal thickening occurs in hypertrophic cardiomyopathy.

A fast, abnormal heart rhythm originating in the ventricles. Can be life-threatening if sustained and may degenerate into ventricular fibrillation. Treated with medications, catheter ablation, or an ICD.

A blood-thinning medication (brand name Coumadin) that inhibits vitamin K-dependent clotting factors. Required for life after mechanical valve implantation. Requires regular INR blood testing to maintain the proper dose.

A congenital condition in which an extra electrical pathway between the atria and ventricles causes rapid heartbeats (tachycardia). Can usually be cured with catheter ablation to destroy the accessory pathway.

Post-surgical care of the incision site to prevent infection and promote healing. Involves keeping the wound clean and dry, monitoring for signs of infection (redness, swelling, drainage), and following up with the surgical team.