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cardiovascular disease  (CVD)

disease affecting the heart peripheral blood vessels or both

coroary heart disease  (CHD)

a type of CVD; the single largest killer of americans


communication between two or more vessels

Poiseyille's law

a law of physiology stating that blood flow through a vessel is directly proportional to the radius of the vessel to the fourth power

cardiac cycle

the period of time from the end of one cardiac contraction to the end of the next


the period of time when the myocardium is relaxed and cardiac filling and coronary perfusion occur


the period of the cardiac cycle when the myocardium is contracting

ejection fraction

ratio of blood pumped from the ventricle to the amount remaining at the end of diastole

stroke volume

the amount of blood ejected by the heart in one cardiaccontraction


the pressure within the ventricles at the end of diastole; commonly called the end-diastolic volume

Starling's law of the heart

law of physiology stating that the more the myocardium is stretched, up to a certain amount, the more forceful the subsequent contraction will be

cardiac output

the amount of blood pumped by the heart in 1 minute


the resistance against which the heart must pump


pertaining to the heart


pertaining to cardiac contractile force


pertaining to the speed of impulse transmission

intercalated discs

specialized bands of tissue inserted between myocardial cells that increase the rate in which the action potential is spread from cell to cell


group of cardiac muscle cells that physiologicaly function as a unit

cardiac depolarization

a reversal of charges at a cell membrane so that the inside of the cell becomes positive in relation to the outside; the opposite of the cell's resting state in which the inside of the cell is negative in relation to the outside

resting potential

the normal electrical state of cardiac cells

action potential

the stimulation of myocardial cells, as evidenced by a change in the membrane electrical charge, that subsequently spread across the myocardium


return of a muscle cell to its preexcitation resting state


ability of the cells to respond to an electrical stimulus


ability of the cells to propagate the electrical implulse from one cell to another


pacemaker cells' capability of self-depolarization


ability of muscle cells to contract, or shorten

rhythm strip

electrocardiogram printout

electrocardiogram (ECG)

the graphic recording of the heart's electrical activity.  It may be displayed either on paper or on an oscilloscope


deflection on the ECG produced by factors other than the heart's electrical activity

bipolar limb leads

electrocardiogram leads applied to the arms and legs that contain two electrodes of opposite (positive and negative) polarity; leads I, II, and III.

Einthoven's triangle

the triangle around the heart formed by the bipolar limb leads

augmented limb leads

another term for unipolar limb leads (see the following definition), reflecting the fact that the ground lead is disconnected, which increases the ampliude of deflection on the ECG tracing

unipolar limb leads

elerocardiogram leads applied to the arms and legs, consisting of one polarized (positive) electrode and a nonpolarized referenced point that is created by the ECG machine combining two additional electrodes; also called augmented limg leads; lead aVR, aVL, and aVF

precordial (chest) leads

electrocardiogram leads applied to the chest in a pattern that permits a view of the horizontal plane of the hert; leads V1, V2, V3, V4, V5, and V6

QT interval

period from the beginning of the QRS to the end of the T wave

corrected QT (QTc)

The QT interval divided by the square root of the R-R interval

prolonged QT interval

QT interval greater than 0.44 sec.

refractory period

the period of time when myocardial cells have not yet completely reploarized an cannot be stimulated again

absolute refractory period

the period of the cardiac cyle when stimulation will not produce any depoloarization whatever

relative refractory period

the period of the cardiac cycle when a suffiiently strong stimulus may produce depolarization


a heart rate greater than 100 beats per minute


a heart rate less than 60 beats per minute

normal sinus rhythm

the normal heart rhythm


any deviation from the normal electrical rhythm of the heart


the absence of cardiac electrical activity; often used interchangeable with dysrhythmia

ectopic focus

nonpacemaker heart cell that automatically depolarizes (plural: ectopic foci)

ectopic beat

cardiac depolarization resulting from depolarization of ectopic focus

noncompensatory pause

pause following an ectopic beat where the SA node is depoloarized and the underlyin cadence of the heart is interrupted


the sound of turbulent blood flow through a vessel; usually associated with atherosclerotic disease

compensatory pause

the pause following anectopic beat where the SA node is unaffected and the cadence of the heart is uninterrupted

interpolated beat

a PVC that falls between two sinus beats without effectively interrupting this rhythm

coupling interval

distance between the preceding beat and the PVC

aberrant conduction

conduction of the electrical impulse through the heart's conductive system in an abnormal fashion

bundle branch block

a knd of interventricular heart block in which conduction through either the right or left bundle branches is blocked or delayed

bundle of Kent

an accessory AV conduction pathway that is thought to be responsible for the ECG findings of preexcitation syndrome


the process of passng an elctrical current through a fibrillating heart to depolarize a critical mass of myocardial cells.  This allows them to repolarize uniformly, resulting in an organized rhythm

synchronized cardioversion

the passage of an electric current through the beart during a specific part of the cardiac cycle to terminate certain kinds of dysrhythmias

acute coronry syndrome (ACS)

a spectrum of coronary artery disease processes from myocardial ischemia and myocardial injury to myocardial infarction and includes the clinical entities of stable and unstable angina and acute myocardial infarction

angina pectoris

cheat pain that results when the heart's oxygen requirements exceed oxygen supply available from blood

Prinzmetal's angina

variant of angina pectoris caused by vasospasm of the coronary arteries, not blockage per se; also called vasospastic angina or atypical angna


restoring blood flow to ischemic tissue

myocardial infarction (MI)

death and subequent necrosis of the heart muscle caused by inadequate blood supply; also acute myocardial infarction (AMI)

transmural infarction

myocardia infarction that affects the full thickness of the myocardium and almost always results in a pathological Q wave in the affected leads

ST-segment elevation myocardial infarction (STEMI)

a transmural (Q wave) myocardial infarction in which Q waves may appear fairly late in the infarction, but ST segment elevation occurs almost immediately; usually caused by complete obstruction of a coronary artery, involving the full thickness of the heart wall

subendocardial infarction

myocardial infarcton that affects only the deeper levels of the myocardium; also called non-Q wave infarction because it typically does not result in a significant Q wave in the affected lead

non-ST-segment elevation myocardial infarction (NSTEMI)

a subendocardial myocardial infarction that typically presents with normal or depressed ST segments and no Q wave development; usually caused by partial obstruction of a coronary artery and involving less than the full thickness of the heart wall

percutaneous coronary intervention (PCI)

placement of a catheter into an artery and its advancement to the heart to aid in visualizing the coronary arteries

coronary arteriogram/coronary angiogram

administration of a radiographic contrast dye into the coronary arteries via a catheter advanced from a remove artery to permit radiographic visualization of the coronary arteries and any possible obstructions or lesions to these arteries

percutaneious transluminal coronary angioplasty (PTCA)

insertion and inflation of a balloon into an artery to dilate an obstructed artery

primary coronary stenting

insertion of a wire mesh scaffold to prop open an artery recently cleared by angioplasty

coronary artery bypass grafting (CABG)

a surgical procedure in which the saphenous vein from one leg or an internal mammary artery is harvested and used to construct a bypass around the bloacked area of an artery that is not amenable to clearing by PCI techniques.  Also called aortocoronary grafting

heart failure

clinical syndrome in which the heart's mechanical performance is compromised so that cardiac output cannot meet the body's needs

pulmonary embolism (PE)

blood clot in one of the pulmonary arteries

congestive heart failure (CHF)

condition in which the heart's reduced stroke volume causes an overload of fluid in the body's other tissues

paroxysmal nocturnal dyspnea (PNA)

a sudden episode of difficult breathing that occurs after lying down; most commonly caused by left-heart failure

cardiac tamponade

accumulation of excess fluid inside the pericardium

hypertensive emergency

an acute elevation of blood pressure that requires the blood pressure to be lowered within 1 hour; characterized by end-organ changes such as hypertensive encephalopathy, renal failure or blindness

hypertensive encephalopathy

a cerebral disorder of hypertension indicated by severe headache, nausea, vomiting, and altered mental status.  Neurologic symptoms may include blindness, muscle twitches, inability to speak, weakness, and paralysis

cardiac shock

the inability of the heart to meet the metabolic needs of the body, resulting in inaduquate tissue perfusion

cardiac arrest

the absence of ventricular contraction

sudden death

death within 1 hour after the onset of symptoms


duration from the beginning of the cardiac arrest until effective CPR is established

total downtime

duration from the beginning of the arrest until the patient's delivery to the emergency department


provision of efforts to return a spontaneous pulse and breathing

return of psontaneous circulation (ROSC)

resuscitation results in the patient's having a spontaneous pulse


when a patient is resuscitated and survives to be discharged from the hospital


a progressive, degenerative disease of the midsize and large arteries


a thickening, loss of elastivity, and hardening of the walls of the arteries from calcium deposits


severe pain in the calf muscle due to inadequate bood supply.  It typically occurs with exertion and subsides with rest


the ballooning of an arterial wall, resulting from a defect or weakness in the wall

dissecting aortic aneurysm

aneurysm caused when blood gets between and separates the layers of the aortic wall

cystic medial necrosis

a death or degeneration of a part of an artery wall

acute pulmonary embolism

blockage that occurs when a blood clot or other particle lodges in a pulmonary artery

acute arterial occlusion

the sudden occlusion of arterial blood flow


inflammation of blood vessels

peripheral arterial atherosclerotic diease

a progressive degenerative disease of the midsize and large arteries

deep venous thrombosis

a blood clot in a vein

varicose veins

dilated superficial veins, usually in the lower extremity


a force that has both magnitude and direction

QRS axis

reduction of all the heart's electrical forces to a single vector represented by an arrow moving in a single plane

right axis deviation

a calculated axis of the heart's electrical energy that equals or exceeds +105o (or in a simplified formula, from +90 to +180o)

left axis

a calculated axis of the heart's electrical energy that equals or exceeds -30o (or in a simplified formula, from 0 to -90o)

indeterminate axis

a calculated axis of the heart's electrical energy from -90o to -180o. (Indeterminate exis is often considered to be extreme right axis deviation.)

myocardial ischemia

deprivation of oxygen and other nutrients to the myocardium (heart muscle), typically causing abnormalities in repolarization

myocardial injury

injury to the myocardium (heart muscle), typically following myocardial ischemia that results from loss of blood and oxygen supply to the tissue.  The injured myocardium tends to be partially or completely depolarized

current of injury (injury current)

the flow of current between the pathologically depolarized area of myocardial injury and the normally depolarized areas of the myocardium


a morror image seen typically on the opposite wall of the injured area


stretching; enlargement without any additional cells