Cardiac Stress Imaging is a group of diagnostic tests that evaluate the heart under “stress” (exercise or medication-induced) and at rest. It is used to detect problems with blood flow to the myocardium (heart muscle) and to assess cardiac function during increased demand. It belongs to cardiovascular diagnostics and commonly supports evaluation of chest pain, dyspnea (shortness of breath), and known or suspected coronary artery disease (CAD). It is frequently used in outpatient cardiology, emergency department risk assessment pathways, and pre-operative cardiac evaluation.

Cardiac Enzymes are blood-based biomarkers used to detect injury to heart muscle (myocardium). They are most commonly discussed in emergency and inpatient cardiology when evaluating chest pain and suspected acute coronary syndrome (ACS). In practice, the term often includes non-enzyme proteins such as cardiac troponins because they serve the same diagnostic purpose. They are used alongside the electrocardiogram (ECG), clinical history, and imaging to assess myocardial injury and myocardial infarction (MI).

Contractility is the intrinsic ability of cardiac muscle to generate force and shorten during systole. It is a core physiology concept used to describe how strongly the ventricle can contract at a given preload and afterload. Clinically, Contractility is discussed in heart failure, shock, ischemia, and during use of inotropes. It is commonly inferred from bedside findings, echocardiography, and hemodynamic data rather than measured directly.

Preload is the stretch of cardiac muscle at the end of filling, just before contraction. It is a physiology concept most closely related to ventricular end-diastolic volume and pressure. Preload is commonly discussed in heart failure, shock, and perioperative and critical care cardiology. Clinicians use it to interpret hemodynamics and to predict how stroke volume may change with volume shifts.

Afterload is the force the ventricle must overcome to eject blood during systole. It is a core cardiovascular physiology concept used in bedside assessment and hemodynamic reasoning. It is discussed in conditions like hypertension, heart failure, and valvular disease. It is commonly referenced when interpreting blood pressure, echocardiography, and invasive hemodynamics.

Hemodynamics is the study of blood flow and pressure in the cardiovascular system. It describes how the heart pumps blood through arteries, capillaries, and veins. It is a core physiology concept used in cardiology, critical care, anesthesia, and cardiothoracic surgery. It is commonly applied at the bedside, on echocardiography, and during cardiac catheterization.

Cardiac Index is a hemodynamic measure of blood flow from the heart adjusted for body size. It is calculated as cardiac output divided by body surface area (BSA). It is used in cardiovascular physiology, critical care, and perioperative medicine to describe global circulatory performance. It is most commonly discussed in shock, heart failure, and invasive or noninvasive hemodynamic monitoring.

Endocardial Cushion Defect is a congenital heart defect involving abnormal formation of the atrioventricular (AV) septum and AV valves. It is an anatomic and developmental cardiac condition rather than a diagnostic test or a treatment. It is most commonly discussed in pediatric cardiology, congenital heart disease clinics, and cardiothoracic surgery planning. It is closely related to atrioventricular septal defect (AVSD), including defects of the atrial and/or ventricular septum and AV valve structure.

Pericardial Effusion is an abnormal accumulation of fluid in the pericardial space around the heart. It is an anatomic and pathologic concept that can reflect many underlying diseases. It is commonly identified on transthoracic echocardiography (TTE) and may be supported by computed tomography (CT) or cardiac magnetic resonance (CMR). Its clinical importance ranges from incidental imaging findings to life-threatening cardiac tamponade.

Cardiac Tamponade is a life-threatening form of obstructive shock caused by pressure on the heart from fluid, blood, or air within the pericardial sac. It is a hemodynamic syndrome rather than a single disease, defined by impaired cardiac filling and reduced cardiac output. It sits at the intersection of cardiac anatomy (pericardium) and acute cardiovascular pathology (shock). It is commonly discussed in emergency medicine, cardiology, intensive care, and perioperative cardiothoracic care.