Iran Specialty Board - Cardiology key terms

The ratio of maximal coronary blood flow in a stenotic artery to maximal flow in the same artery if it were normal, estimated from pressure measurements during hyperemia. Values at or below 0.80 identify ischemia-producing lesions that benefit from revascularization.

A resting pressure-derived index of coronary stenosis severity measured during the wave-free period of diastole, when microvascular resistance is low and stable. It avoids adenosine and uses a threshold of 0.89 for revascularization decisions.

Acute myocardial infarction with angiographically normal or near-normal coronary arteries, defined as no stenosis of 50 percent or more, in the absence of an alternative overt cause. Mechanisms include plaque disruption, vasospasm, embolism, and spontaneous coronary artery dissection.

Non-atherosclerotic, non-traumatic separation of the coronary arterial wall by an intramural hematoma, compressing the true lumen. It predominantly affects younger women and is managed conservatively in most cases because percutaneous intervention carries high complication rates.

Assays detecting troponin at concentrations far below conventional methods, used with serial sampling and delta criteria to diagnose or exclude acute myocardial infarction rapidly. Interpretation requires attention to chronic elevations from kidney disease, heart failure, and structural cardiac disease.

Myocardial infarction caused by a supply-demand mismatch, such as severe anemia, tachycardia, hypotension, or sepsis, rather than by acute atherothrombotic plaque rupture. Treatment targets the underlying precipitant, and antithrombotic therapy is not routinely indicated.

The proportion of end-diastolic ventricular volume ejected per beat, calculated as stroke volume divided by end-diastolic volume. It is central to heart failure classification, device eligibility decisions, and cardiotoxicity surveillance.

A clinical heart failure syndrome with an ejection fraction of 50 percent or more and evidence of elevated filling pressures or diastolic dysfunction. It is common in older patients with hypertension, obesity, and atrial fibrillation, and is treated with sodium-glucose cotransporter-2 inhibitors and diuretics.

A combined neprilysin inhibitor and angiotensin receptor blocker that increases natriuretic peptide activity while blocking angiotensin II effects. It reduces mortality and hospitalization in heart failure with reduced ejection fraction and requires a washout when switching from an ACE inhibitor.

A drug class combining an angiotensin receptor blocker with a neprilysin inhibitor, of which sacubitril/valsartan is the prototype. Neprilysin inhibition raises natriuretic peptide levels, promoting natriuresis and vasodilation in heart failure.

An oral glucose-lowering drug class that also reduces heart failure hospitalization and cardiovascular death in patients with reduced or preserved ejection fraction, largely independent of diabetes status. Mechanisms involve natriuresis, improved cardiac energetics, and reduced preload.

An inherited myocardial disorder, most often sarcomeric, characterized by unexplained left ventricular hypertrophy with a nondilated cavity. Dynamic left ventricular outflow tract obstruction, diastolic dysfunction, and sudden death risk drive management decisions.

A drug class, including mavacamten, that reduces actin-myosin cross-bridge formation and thereby lowers dynamic left ventricular outflow tract obstruction in hypertrophic cardiomyopathy. It requires monitoring of ejection fraction because of the risk of systolic dysfunction.

Deposition of misfolded proteins, most commonly transthyretin or immunoglobulin light chains, within the myocardium, producing thickened walls, restrictive physiology, and heart failure. Noninvasive bone scintigraphy can diagnose transthyretin disease without biopsy when plasma cell dyscrasia is excluded.

A myocardial disorder with impaired ventricular filling and normal or reduced cavity size, usually with preserved systolic function and biatrial enlargement. Causes include amyloidosis, sarcoidosis, endomyocardial fibrosis, and infiltrative diseases.

Classification of aortic stenosis using peak velocity, mean gradient, and calculated valve area, with subdivision into low-flow low-gradient and normal-flow low-gradient patterns. Severe disease is defined by a mean gradient of 40 mmHg or more or a valve area of 1.0 cm squared or less.

Severe aortic stenosis with a small calculated valve area, low mean gradient, low stroke volume index, and preserved ejection fraction, typically in older patients with small, hypertrophied ventricles. Dobutamine stress echocardiography is not useful; calcium scoring or CT helps confirm severity.

Catheter-based replacement of the aortic valve, usually via transfemoral access, without sternotomy or cardiopulmonary bypass. It is the preferred approach for most older patients with symptomatic severe aortic stenosis and high or intermediate surgical risk.

Calcific deposition in the mitral annulus, associated with aging, chronic kidney disease, and hypertension. It can cause mitral regurgitation or stenosis and complicates surgical and transcatheter valve intervention because of the risk of annular rupture.

A point-based estimate of stroke risk in atrial fibrillation incorporating heart failure, hypertension, age, diabetes, prior stroke, vascular disease, and sex. It guides decisions about oral anticoagulation, with anticoagulation generally recommended at a score of 2 or more in men and 3 or more in women.

Percutaneous or surgical closure of the left atrial appendage to reduce cardioembolic stroke in atrial fibrillation when long-term anticoagulation is contraindicated or poorly tolerated. Device implantation requires imaging guidance and short-term antithrombotic therapy during endothelialization.

A device that monitors the heart rhythm and delivers antitachycardia pacing or shocks to terminate ventricular arrhythmias. Indications include secondary prevention after sustained ventricular arrhythmia and primary prevention in selected patients with reduced ejection fraction or inherited arrhythmia syndromes.

Biventricular pacing designed to correct dyssynchrony in patients with heart failure and a prolonged QRS duration, typically with left bundle branch block. It improves symptoms and survival in appropriately selected patients with reduced ejection fraction.

Ablation, usually by pulmonary vein isolation, intended to eliminate triggers of atrial fibrillation and maintain sinus rhythm. It is most effective in younger patients with paroxysmal disease and minimal atrial remodeling, and is often performed after failed antiarrhythmic drug therapy.

Catheter-based interruption of sympathetic nerves surrounding the renal arteries, investigated as a treatment for resistant hypertension. Blood pressure reduction in sham-controlled trials has been modest, and the procedure remains adjunctive rather than standard therapy.

Blood pressure above goal despite adherence to three antihypertensive agents of different classes at optimal doses, including a diuretic, or controlled blood pressure requiring four or more agents. Evaluation addresses adherence, secondary causes, and drug interactions.

Autonomous aldosterone production, most often from bilateral adrenal hyperplasia or a unilateral adenoma, causing hypertension with suppressed renin. Screening uses the aldosterone-to-renin ratio, and treatment is mineralocorticoid receptor antagonism or adrenalectomy.

A tear in the aortic intima allowing blood to enter the media and create a false lumen, classified as type A when the ascending aorta is involved. Type A requires urgent surgery, while uncomplicated type B is usually managed medically.

Hemorrhage within the aortic media without a demonstrable intimal tear or false lumen flow, often considered a variant of dissection. Management parallels dissection, with surgery for ascending involvement and medical therapy otherwise.

Catheter placement of a stent in the ductus arteriosus to secure pulmonary blood flow in duct-dependent congenital heart lesions when surgical shunting is unfavorable. It is a temporizing palliation, and prostaglandin infusion remains the initial stabilization.

Continuous infusion used to maintain ductal patency in neonates with duct-dependent congenital heart disease, such as critical coarctation or pulmonary atresia. Apnea is a common adverse effect, so airway readiness is required.

Pulmonary arterial hypertension with reversal of a long-standing left-to-right shunt, producing cyanosis and right-to-left flow. It contraindicates shunt closure, and management uses pulmonary vasodilators and avoidance of systemic hypotension.

Compression of the heart by pericardial fluid, raising intrapericardial pressure and impairing diastolic filling. Clinical clues include hypotension, elevated jugular venous pressure, pulsus paradoxus, and echocardiographic chamber collapse; drainage is urgent.

Needle drainage of pericardial fluid, ideally guided by echocardiography, for tamponade or diagnostic evaluation. Access is usually subxiphoid, and complications include ventricular puncture, arrhythmia, and pneumothorax.

A CT-derived quantification of calcified coronary plaque used to refine cardiovascular risk estimation in asymptomatic adults. A score of zero indicates very low short-term risk and often supports deferring statin therapy in uncertain cases.

A lipoprotein consisting of an LDL-like particle covalently bound to apolipoprotein(a), with concentrations largely genetically determined. Elevated levels independently increase atherosclerotic and aortic valve disease risk and are measured once to refine risk assessment.

An echocardiographic measure of myocardial deformation along the long axis, expressed as a percentage and more sensitive than ejection fraction for early systolic dysfunction. A relative reduction during cardiotoxic therapy often prompts cardioprotective treatment.

Controlled cooling, or active avoidance of fever, after cardiac arrest to limit hypoxic-ischemic brain injury. It is combined with hemodynamic support and delayed neuroprognostication to avoid premature withdrawal of care.

Circulatory or respiratory support in which blood is oxygenated outside the body, used in refractory cardiogenic shock or cardiac arrest. Venoarterial ECMO increases left ventricular afterload and requires careful management of venting and limb perfusion.

A study design in which participants are allocated by chance to interventions, minimizing confounding and allowing causal inference. Key appraisal elements include allocation concealment, blinding, intention-to-treat analysis, and reporting of absolute rather than only relative effects.

The reciprocal of the absolute risk reduction, representing how many patients must receive an intervention for one additional favorable outcome. It conveys clinical impact and depends heavily on baseline risk.