| A | B |
|---|
| Anterior MI | infarction of the anterior wall of the heart, most often caused by occlusion of the Left Anterior Desending coronary artery |
| Anterior Surface | the plane of the heart that faces forward, abutting the chest wall |
| Anterobasal MI | anterior wall infarction localized to the base (top) of the heart |
| Anterolateral MI | Anterior wall infarction localized to the area of the lateral wall |
| Anteroseptal MI | Anterior wall infarction localized to the area of the septum |
| Aorta | artery that carries oxygenated blood from the left ventricle to distal parts of the body |
| Aorta Valve | the valve that controls passage of blood from the left ventricle to the aorta |
| Apex | the lower point of the heart |
| Apical MI | infarction localized to the apex (bottom) of the heart |
| Artifact | electrical activity displayed on graph paper that is superimposed on cardiac tracings, interfering with interpretation of the rhythm; can be caused by outside electrical sources, muscle tremors, patient movement; also called interference |
| Asystole | the absense of any cardiac electrical activity; appears as a straight line on graph paper |
| Atria | the upper two chambers of the heart |
| Atria Arrhythmia | a cardiac arrhythmia originating from the conduction system within the atria |
| Atrial Fibrillation | the cardiac arrhythmia in which the atria are controlled by numerous irritable foci, thereby causing ineffectual, chaotic atrial activity and irregular ventricular response |
| Atrial Flutter | the cardiac arrhythmia in which an irritable focus in the atria produces radip, repetive dischage, resulting in rhythmic atrial depolarizations at a rate of 250-350 beats per minute, some of which are usually blocked by the AV node to keep the ventricular rate in a more normal range |
| Atrial Hypertrophy | enlargement of myocardial wall in one or more of the atria |
| Atrial Pacemaker | pacemaker that stimulates only the atrial |
| Atrial Tachycardia | the cardiac arrhythmia in which a single irritable focus in the atria takes over control of the heart to produce a rate of 150-250 beats per minute; this arrhythmia is often paroxysmal in nature, that is, it starts and stops suddenly -- in that instance it is call Paraxysmal Atrial Tachycardia (PAT) |
| Atrioventricular Dissociation | a conduction defect that causes the atria and venticles to depolarize and function independently; AV Dissociation |
| Augemented Leads | unipolar leads that measure electrical flow on the frontal plance from the center of the heart to each of three limb electrodes: Leads aVR, aVL, and aVF |
| Automaticity | the unique ability of cardiac pacemaker cells to initiate spontaneous excitation impulses |
| Autonomic Nevous System | the system responsible for control of involuntary bodily functions, including cardiac and vascular activity; branches are sympathetic nervous system and parasympathetic nervous system |
| AV | artiventricular |
| AV Heart Block | arrhythmias caused by disturbances in conduction through the AV node |
| AV Junction | that part of the cardiac conduction system that connects the atria and the ventricles; contains the AV node and the nonbranching part of the Bundle of His |
| AV Node | a part of the cardiac conduction system located within the AV junction; does not contain pacemaking cells; its purpose is to slow conduction of impulses through the AV junction |
| AV Sequential Pacemaker | a type of artifical pacemaker that senses ventricular activity and, in its absence, paces atria and ventricles in a normal sequence |
| AV Synchronous Pacemaker | a type of artificial pacemaker that sense both atria and ventricles, and paces the ventricles when a spontaneous P wave is not followed by a QRS. The ventricls are depolarized in synchrony with P waves so that atrial and centricular contractions are coordinated |
| Axis | sum direction of electrical flow through the heart. The asix of a given leas is the lead axis. The sum direction of electrical flow through the heart as a whole is the mean QRS axis |
| Axis Deviation | shift in mean QRS axis reflecting myocardial damage, enlargement, or conduction defect |
| Base | the upper end of the heart |
| Baseline | the isolectric line; the line on EKG graph paper thaat indicates lack of electrical activity, and from which all other cardiac wave impulses deviate |
| Bigeminy | a pattern of cardiac electrical activity in which every other beat is an ectopic, usually a PVC |
| Biological Death | the second phase of death, following clinical death; defined by brain death, usually following 4-6 minutes of cardiac arrest if no resuscitation is instituted |
| Biphasic | a single EKG wave that has two deflections, one upright and the other inverted |
| Bipolar Lead | a lead composed of one positive and one negative electrode |
| Block | a defect in conduction within the heart's electrical system |
| Bolus | a single loading dose of a drug; used to achieve a rapid high therapeutic blood level prior to instituting IV drip therapy |
| Bradyarrhythmia | any cardiac arrhythmia with a reate below 60 beats per minute |
| Bradycardia | a heart reate less than 60 beats per minute |
| Bundle Branches | the portion of the cardiac conduction system within the ventricles that conducts impules from the Bundle of His to the Purkinje fibers; consists of right and left bundle branches |
| Bundle Branch Block | a conduction disturbance that prevents or delays passage of implues from the Bundle of His through to the Purkinje networks; can involve the right or left bundle branch, or less frequently, both |
| Bundle of His | that part of the cardiac conduction system that conducts impulses from the AV Junction through to the bundle branches |
| Calibration | the act of standardizing the graphic display of electrical activity; the calibration mark should measure 1 millivolt on the graph paper |
| Capture | the act of responding to an electrical stimulus with depolarizations; generally refers to an arrhythmia's response to an artificial pacemaker |
| Cardiac Arrest | the cessation of cardiac function, resulting in sudden drop in perfusion and resultant clinical death |
| Cardiac Cycle | the interval from the beginning of one heartbeat to the beginning of the next; on the EKG it emcompasses the PQRST complex |
| Cardiac Output | the amount of blood pumped by the left ventricle in 1 minute; it is calculated by multiplying the stroke volume by the heart rate, and is measured in liters per minute |
| Cardioversion | a maneuver used to convert various tachyarrhythmias to more viable rhythms; consists of application of electrical countershock (DC current) to the chest wall; the electrical discharge usually synchronized to fall on the R wave, thus avoiding the relative refractory period |
| Carotid Sinus Massage | a maneuver used to convert various supraventricular tachycardias to a more viable rhythm; consists of gentle massage with fingertips over the carotid sinus in the neck |
| Central Terminal | an electrically neutral reference point created by combining two or more electrodes. It is used to oppose the positive electrode in unipolar leads |
| Chordas Tendonae | specialized fibers that connect valve leaflets to papillary muscles to prevent back-flow during contractions |
| Classical Second Degree Heart Block | the term formerly used to describe the type of AV heart block that is now called Type II Second Degress Heart Block, in which the AV node intermittently blocks sinus impulses, preventing them from being conducted through to the ventricles |
| Clinical Death | the absence of pulse and blood pressure; occurs immediately following cardiac arres |
| Compensatory Pause | the time lag following an ectopic beat before the next normal beat occurs; is identified by measureing the interval from the R wave immediately preceding the ectopic to the R wave immediately following it; a fully compensatory pause (such as occurs following most PVCs) will be exactly two times the normal R-R interval |
| Competition | condition in which an artificial pacemaker competes with the patient;s intrinsic pacemaker for control of the heart |
| Complete Heart Block | Third Degree AV Block; a form of AV dissociation |
| Conduction Ratio | the number of P waves to QRS complexes. One P wave for every QRS complex is a 1:1 conduction ratio. Three P waves from every QRS complex would be a 3:1 conduction ratio |
| Conduction System | the pathways of conductive tissues within the heart that facilitate passage of electrical impules throughout the myocardium |
| Conductivity | the property of some cardiac cells that enables them to transmit electrical impusses |
| Contractility | the ability of heart muscle to contract in respose to electrical stimulation |
| Conventional 12-Lead EKG | electrocardiogram that provides images of cardiac electrical activity from 12 perspectives simultaneously |
| Coronary Arteries | Those blood vessels that supply the ehart muscle itself. The major branches are the Left Coronary Artery (with the Left Anterior Descending branches and the Circumflex branch) and the Right Coronary Artery |
| Coronary Sinus | the reentry point within the right atruum where deoxygenated blood returns after having supplied the heart muscle itself |
| Defibrillation | application of electrical countershock (DC current) to the chest wall to terminate vertricular tachyarrhythmias |
| Demand Pacemaker | pacemaker thtat senses patient's intrinsic complexes and fires only when needed |
| Depolarization | the electrical process of discharging polarized cells, ussually resulting in muscle contraction |
| Diaphragmatic Surface | the plane of the heart that faces downward, resting aginst the diaphragm |
| Diastole | the phase of the cardiac cycle in which chambers are relasing |
| Digitalis Toxicity | excessive blood levels of the heart drug Digitalis |
| Dissociation | independent function of two parts, generally the atria and ventricles |
| Dual-Chamber Pacemaker | paces both artia and ventricles |
| Dysrhythmia | arrhythmia |
| ECG | electrocardiogram; EKG |
| Ectopic | originating from a focus other than the primary pacemaker |
| Einthoven's Triangle | the triangle created by an imaginary line connecting the three chest electrodes used to create the standard limb leads |
| EKG | electrocardiogram; ECG |
| Electrocardogram | EKG, ECG; graphic representation of the electrical activity in the ehart |
| Electrode | metal wire attached to the patient's body for the purpose of conveying electrical impulses to a machine for recording or displaying |
| Endocardium | the inner layer of the heart wall that contains the branches of the heart's electrical system |
| Epicardium | the outside layer of the heart wall that contains the coronary blood vessels and nerves |
| Equiphasic | a single EKG wave that has two deflections of equal magnitude, one upright and the other inverted |
| Escape | the mechanism that allows a lower pacemaker site to assume pacemaking responsibility when a higher site fails |
| Evolving Infarction | the changing EKG picture associated with the passage of time followng myocardial infarction |
| Failure to Capture | situation in which the pacemaker fires but the patient's heart does not respond with depolarization |
| Fibrillation | chacotic, ineffective movement of the heart muscle |
| First Degree Heart Block | a type of AV heart block characterized by prolonged but consistent conduction of atrial impulsses through to the ventricles |
| Fixed-Rate Pacemaker | pacemaker that is set at a pre-determined rate and fires regardless of the pateint's underlying rhythm |
| Flutter | rhythmic, rapid beating of the heart muscle |
| Gallop Rhythm | heart sounds that are grouped together so they sound like galloping horses |
| Heart Block | AV heart block |
| Heart Rate | the number of heartbeats per minute |
| Heart Sounds | sounds associated with flow of blood through heart chambers and closing of heart valves. The four components as S1: closure of mitral and tricuspid valves; S2: closure of aotric and pulmonic valves; S3: abnormally rapid ventriclar filling; S4: abnormally forceful atrial contraction |
| His-Purkinje System | the lower part of the cardiac conduction system that transmits implueses throughout the centricles; located in the interventricular septum and centricular walls |
| Hyperkalemia | high blood potassium level |
| Hypertrophy | enlargement of myocardial wall in one or more of the chambers of the heart |
| Hypokalemia | low blood potassium level |
| Idioventricular Rhythm | a ventricular escape rhythm; characterized by a rate of less than 40 beats per minute |
| Inferior MI | infarction of the inferior wall of the heart. most often casued by occulsion of the right coronary artery |
| Interior Vena Cava | vein that carries deoxygenated blood from the lower body back to the right atrium |
| Interference | electrical activity displayed on graph paper that is superimposed on cardiac tracings, interfering with interpretatin of the rhythms; can be casued by outside electrical sources, muscle tremors, patient movement; also called artifact |
| Interpolation | the placement of an ectopic (especially PVCs) between two normal beats without distrubing the regularity of the underlying rhythm |
| Interval | distance between two points on an EKG tracing |
| Interventricular Septum | the muscular wall dividing the right and left ventricles |
| Intratrial Pathways | branches of the cardiac conduction system that service the artia |
| Intraventricular Conduction Defect | disturbance in conduction involving one or more of the bundle branches. Also called Bundle Branch Block |
| Ischemic Changes | changes on the EKG that reflect myocardial ischemia: ST elevation, ST depression, Q wave deepening, and T wave inversion |
| Isolectric Line | the line created on EKG graph paper when no lectrical current is flowing; see also Baseline |
| Junction | that part of the cardiac conduction system that connects the artria and the ventricles |
| Junction Escape Rhythm | an arrhythmia resulting from failure of a higher pacemaker site, allowing the AV junction to pace the heart at a bradycardia rate |
| Junction Tachycardia | a rapid arrhythmia originating in the AV junction |
| Lateral MI | infarction of the lateral wall of the heart, most often casued by occlusion of the Left Anterior Descending coronary artery |
| Lateral Surface | the plane of the heart that faces the side, just above the diaphragmatic surgace |
| Lead | an electrocardiographic view of the heart, gained by recording the electrical activity between two or more electrodes |
| MCL1 | Modified Chest Left; a monitoring lead that minics V1 and is useful in differentiatin tachycardia |
| MI | tissue death caused by lack of oxygen to the myocardium |
| Millivolts | a measure of electricity; 1 volt equals 1000 millivolts |
| Mitral Vavle | the valve that controls passage of blood from the left atrium to the left ventricle |
| Monitor | the machine on which electrocardiographic impulses are displayed; oscilloscope |
| Monitoring Lead | a lead that clearly shows individual wave forms and is useful for monitoring cardiac rhythm, most often Lead II or MCL1 |
| Multifocal | term used to describe ectopic beats that originate from more than one irritable focus |
| Murmurs | heart sounds caused by abnormal turbulence associated with high flow rates, damaged vavles, dilated chambers, or backward flow |
| Myocardial Infarction | tissue death caused by lack of oxygen to the myocardium |
| Myocardial Injury | damage caused by sustained lack of oxygen |
| Myocardial Ischemia | initial tissue response to lack of oxygen |
| Myocardium | the center layer of the heart wall consisting of cardiac muscle fibers |
| Noise | electrical interference displayed on graph paper that interferes with interpretation of the underlying arrhythmia |
| Non-Q Infarction | myocardial infarction that fails to produce classic Q wave changes, most often because the infarcted areas is limited to partial thickness of teh myocardium; subendocardial infarction |
| Normal Sinus Rhythm | the usual cardiac electric pattern of health people |
| Oscilloscope | display device with a screen for viewing EKG and other physiological information; monitor |
| PAC | Premature Atrial Contractions; an ectopic beat created when an irritable focus in the atrium assumes pacemaking responsibility for a single beat |
| Pacemaker | the source of electrical stimulation for cardiac rhythm |
| Pacemaker, Artifical | a device to produce artifical electrical stimuli to myocardial tissue to cause myocardial depolarization |
| Pacemaker Electrodes | the conducting wire that connects to the myocardium to deliver the pacemaker stimulus |
| Pacemaker Site | the site of origin of the electrical stimulation that is causing the cardiac rhythm |
| Papillary Muscles | specialized muscles in the ventricle that attach to heart valves by way of chordae tendonac, enabling the valves to open and close |
| Palpitations | the feeling the patient senses when the heart is beating abnormally |
| Parasympathetic Nervous System | a branch of the autonomic nervous system involved in control of involuntary bodily functions; despress cardiac activity in opposition to the sympathetic branch of teh ANS; efffects include slowing of heart rate and conduction and diminished myocardial irritability |
| Paroxysmal | sudden onset and cessation; often used to describe Atrial Tachycardia if is is characterized by abrupt onset and termination |
| PAT | Paroxysmal Atrial Tachycardia; the term used to describe an Atrial Tachycardia sharacterized by abrupt onset and cessation |
| Pericarditis | inflammation of the pericardial cac surronding the heart. Causes ischemic changes on EKG and can thus be misinterpreted to be MI |
| Pericardium | a thin layer of tissue that forms the pericardial sac to encase the heart in lubricating fluid |
| Permanent Pacemaker | pacemaker that is surgically implanted within the patient's body for an extended time |
| PJC | premature junctional contraction; an ectopic beat originating from an irritable focus in the AV Junction |
| Posterior Surface | the plane of the heart that faces backward, abutting the spine |
| Precordial Leads | leads that measure electrical flow on the horizontal plane, from the center of the heart to locations around the anterior and lateral chest walls. The V leads: V1, V2, V3, V4, V5, and V6 |
| Premature Atrial Contraction | an ectopic beat originating from an irritable focus in the atria |
| Premature Junctional Contraction | an ectopic beat originating from an irritable focus in the AV Junction |
| Premature Ventricular Contraction | an ectopic beat originating from an irritable focus in the ventricles |
| PQRST | a single cardiac cycle on the EKG graph paper; includes the P wave, QRS conples, and T wave, and any segments and intervals between |
| PRI | distance between two points on an EKG tracing |
| PR Interval | the time interval on EKG graph paper measured from the beginning of the P wave to the beginning of the R wave; includes both P wave and the PR segment; indicates time of atrial depolarization |
| PR Segment | the time interval on EKG graph paper measured from the end of the P wave to the beginning of the R wave; indicates delay in AV node |
| Pulmonary Artery | artery that carries deoxygenated blood from the right entricle to the lungs |
| Pulmonary Vein | vein that carries oxygenated blood from the lungs back to the left atruim |
| Pulmonic Valve | the valve that controls passage of blood from the right ventricle to the pulmonary artery |
| Pulse Generator | the power source (battery unit) that drives the pacemaker |
| Pump (Sodium) | the chemical phenomenon that takes place at a cellular level within the cariac electrical conduction system, in which sodium and potassium trade places across the cell wall, thereby initiating the flow of electrical current within the heart |
| Purkinje System | the part of the cardiac conductive system that transmits impulses from the bundle branches to the myocardial cells in the centricles; consists of Purkinje fibers and terminal branches |
| PVC | Premature Ventricular Contractions; an ectopic beat originating from an irritable focus in the ventricles |
| P Wave | the first wave form in the normal cardiac cycle; indicates atrial depolarization |
| QRS Complex | the wave from on an EKG that represents ventricular depolarization' includes the Q, R, and S waves |
| QT Interval | the time interval from the beginnning of the QRS complex to the end of teh T wave; varies with heart rate |
| Quadrigeminy | a cardiac rhythm in which ectopics replace every fourth nomral beat, resulting in a cycle of three normal beats and one ectopic, repeated continously |
| Q Wave | the first negative deflection following the P wave, but before the R wave |
| Reciporcal Changes | EKG deflections seen in leads that are opposite of each other, and thus are mirror images. For example, ST elevation in a facing lead would be ST depression in an opposite lead. Reciprocal changes in anterior leads are used to locate posterior infarctions |
| Refractory Period | that portion of the cardiac cycle in which the heart is unable to respond to electrical stimulation because it has not yet recovered from the preceding depolarization; consists of the Absolute Refractory Period (QRS complex and upslope of the T wave) and the Relative Refractory Period (downslope of the T wave) |
| Relative Refractory Period | the terminal portion of the cardiac refractory period, during which a strong enough electrical stimulus could discharge the heart, resulting inefficient and potentially dangerous arrthythmias; located on the downslope of teh T wave |
| Repolarization | the process of recharging depolarized cels back to their "ready" (polarized) state |
| Retrograde Conduction | electrical current that arises from the area of the AV junction and travels backward up toward the SA node to depolarize the atria in the opposite direction of normal |
| Rhythm | the regularity of a cardiac pattern; generally used to refer to the arrhythmia inself, rather than its rhythmicity (i.e., :The patient's rhythm is Atrial Fibrillation") even though Atrial Fibrillation is an irregular arrhythmia; synonymous with arrhythmia |
| "R on T" Phenomenon | the situation in which the R wave of a PVC occurs on or near the downslope of the preceding T wave, thereby falling in the vulnerable phase of that cardiac cycle, the RElative Refractory Period, and threatening to cause premature discharge and result in an ineffective pattern such as Ventricular Tachycardia or Ventricular Fibrillation. |
| Runaway Pacemaker | a pacemaker malfunction that causes it to fire at an excessive rate |
| R Wave | the first upright deflection following the P wave, or the first positive wave of teh QRS complex |
| Second Degree Heart Block, Type I | a type of second degree heart block in which sinus impulses are delayed at the AV node for increasinly long periods, until conduction is blocked completely, then the cycle repeats itself; Wenchebach. (Formerly called Mobitz Type I) |
| Second Degree Heart Block, Type II | a type of second degree heart block in which the AV node selectively blocks some beats while allowing others to pass through to the centricles. The EKG chows more P waves than QRS complexes; some P waves are not followed by QRS complexes. (Formerly called Classic Second Degree Heart Block, or Mobitz Type II |
| Septum | the wall that divides the heart nto right and left sides. The thin wall between the atria is called the interatrial septum. The thicker wall between the ventricles is the interventricular septum |
| Single-Chamber Pacemaker | paces only the atria or the ventricles, but not both |
| Sinus Arrhythmia | the arrhythmia in which the pacemaker is located in the SA Node but discharges irregularly; usually correlated with respirations; rate increases on inspiration and decreased on expiration |
| Sinus Bradycardia | the arrhythmia in which the pacemaker is located in the SA Node but discharges at a rate less than 60 beats per minute |
| Sinus Node | the normal pacemaker of the heart; located at the junction of teh superior vena cava and the right atrium; SA Node; SinoAtrial Node |
| Sinus Rhythm | any rhythm that originates in the Sinus (SA) Node; used loosely to refer to Normal Sinus Rhythm |
| Sinus Tachycardia | the arrhythmia in which the pacemaker is located in the SANode byt discharges at a rate greater than 100 beats per minute |
| Sodium Pump | the chemical phenomenon that takes place at a cellular level within the cariac electrical conduction system, in which sodium and potassium trade places across the cell wall, thereby initiating the flow of electrical current within the heart |
| Standardization | the act of calibrating the EKG machine or oscilloscope to a standard ( 1 millivolt) |
| Standard Limb Leads | the bipolar leads showing the frontal plane: Leads I, II, and III |
| Stroke Volume | the amount of blood ejected with each contraction of the left ventricle |
| ST Segment | the portion of the cardiac cycle between the S wave and T wave |
| Subendocardial Infarction | infarcted area too small to extend all the way through the ventricular wall; also called a less-than-transmural infarction, or non-Q infarction, since the damage is ofter insufficient to create the classic Q wave change seen with larger infarctions |
| Superior Vena Cava | vein that carries deoxygenated blood from the upper body back to the right atrium |
| Supraventricular | originating above the ventricles |
| Supraventricular Tachycardia | term used to describe a rapid arrhythmia that is regular, has no visible P waves, and has a rate range common to other arrhythmias, thereby making more accurate identification impossible; commonly applied to Atrial TAchycardia, and Atril Flutter with 1:1 response; loosely used to refer to any tachycardia that originated above the ventricles |
| S Wave | the second negative deflection following the P wave, or the first negative deflection following the R wave |
| Sympathetic Nervous System | one of the two main branches of teh autonomic nervous system, which controls involuntary bodily functions; stimulates cardiac activity in opposition to the parasympathetic branch; effects include increased heart rate and conduction and increased myocardial irritability |
| Tachyarrhythmia | any cardiac arrhthymia with a ventricular rate greater than 100 beats per minute |
| Tachycardia | heart rate greater than 100 beats per minute |
| Temporary Pacemaker | pacemaker used in acute setting to stabillize and maintain patient for short periods |
| Thirf Degree Heart Block | the arrhythmia in which all atrial impulses are prevented from reaching the ventricles because of a complete block at the AV node; constitutes a form of AV dissociation because atria and ventricles function totally independent of each other; Complete Heart Block (CHB) |
| Transcutaneous Pacemaker | pacemaker stimulus delivered across the skin via external pads |
| Transmural Infarction | infarcted area large enough to extend completely through the wall of the ventricle |
| Transvenous Pacemaker | pacemaker wire inserted through a vein |
| Tricuspid Valve | the valve that controls passage of blood from the right atrium to the right ventricle |
| Trigeminy | a pattern in which ectopics occur every third beat, producing a repetitive cycle of two normal heart beats and one ectopic |
| Uniphasic | a single EKG wave that has only one phase, either upright or inverted |
| Unipolar Lead | a lead that has only one charged electrode (positive electrode). The opposing pole is created by combining other electrodes into an electrically neutral reference point (central terminal) |
| U Wave | low voltage wave following the T wave, havng the same polarity as the T wave. Usually not apparent, but becomes more pronounced in hypokalemia |
| Variable Conduction | a changing conduction ratio within a given strip. For example, rather than having a consistent ratio of 2 Ps for every QRS comples (a 2:1) acrose an entire strip, a variable conduction would show 2:1, then 3:2, then back to 2:1, or maybe 4:3, all within the same strip |
| Vector | direction of flow of cardiac electrical activity; represented by an arrow with the point indicating the positive pole and the size of arrow indicating magnitude of current |
| Ventricle | the lower two chambers of the heart |
| Ventricular Depolarization | discharge of electrical activity throughout the ventricles to stimulate ventricular contraction; produces the QRS complex on an EKG |
| Ventricular Fibrillation | the arrhythmia in which the ventricles are controlled by numerous irritable foci, producing chaotic, ineffective muscle activity rather than the normal contraction |
| Ventricular Flutter | the arrhythmia in which a single irritable focus in the ventricles depolarized the heart at a rate greater than 250 beats per minute; usually considered to be a rapid form of Ventricular Tachycardia |
| Ventricular Hypertrophy | enlargement of myocardial wall in one or more of the ventricles |
| Ventricular Pacemaker | pacemaker that stimulates only the ventricles |
| Ventricular Standstill | the arrhythmia in which the ventricles are not depolarized by any electrical stiumlation, and therefore do not contract; if atrial activity is presentl it is not conducted through the AV node; if no atrial activity is present it is called Asystole |
| Ventricular Tachycardia | the arrhythmia in which a single irritable focus in the ventricle depolarized the heart at a rate of 150-250 beats per minute |
| Vulnerable Period | the period in the cardiac cycle when the heart is most susceptible to premature dischage with a resultant ineffective pattern if is receives a strong enough electricaly stimulus; the Relative Refreactor Period; corresponds with the downslope of the T wave |
| Wandering Pacemaker | the arrhythmia in which the pacemaker stie shifts from the SA node to the atruim and back again, sometimes dropping as low as the AV junction |
| Waves | deflections on the electrocardiograph caused by changes in electrical activity in the heart |
| Wenchebach | the form of second degree AV block in which the node progressively holds each impulse longer until one is eventually not conducted, then the cycle starts over; Tpe I Second Degree Heart Block |
