Electrocardiography

electrocardiogramECGEKGelectrocardiographelectrocardiographicelectrocardiogramsECG monitorECGsheart monitorelectrocardiographs
Electrocardiography is the process of producing an electrocardiogram (ECG or EKG), a recording – a graph of voltage versus time – of the electrical activity of the heart using electrodes placed on the skin.wikipedia
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T wave

T-waveTT waves
There are three main components to an ECG: the P wave, which represents the depolarization of the atria; the QRS complex, which represents the depolarization of the ventricles; and the T wave, which represents the repolarization of the ventricles.
In electrocardiography, the T wave represents the repolarization of the ventricles.

P wave (electrocardiography)

P waveP wavesP-wave
There are three main components to an ECG: the P wave, which represents the depolarization of the atria; the QRS complex, which represents the depolarization of the ventricles; and the T wave, which represents the repolarization of the ventricles.
The P wave on the ECG represents atrial depolarization, which results in atrial contraction, or atrial systole.

Atrial fibrillation

atrial fibrilationparoxysmal atrial fibrillationAtrial fibrillation with rapid ventricular response
Changes in the normal ECG pattern occur in numerous cardiac abnormalities, including cardiac rhythm disturbances (such as atrial fibrillation and ventricular tachycardia), inadequate coronary artery blood flow (such as myocardial ischemia and myocardial infarction), and electrolyte disturbances (such as hypokalemia and hyperkalemia).
A diagnosis is made by feeling the pulse and may be confirmed using an electrocardiogram (ECG).

Hyperkalemia

high blood potassiumhyperkalaemiahigh blood potassium levels
Changes in the normal ECG pattern occur in numerous cardiac abnormalities, including cardiac rhythm disturbances (such as atrial fibrillation and ventricular tachycardia), inadequate coronary artery blood flow (such as myocardial ischemia and myocardial infarction), and electrolyte disturbances (such as hypokalemia and hyperkalemia).
High levels can be detected on an electrocardiogram (ECG).

Coronary artery disease

coronary heart diseaseischemic heart diseaseischaemic heart disease
Changes in the normal ECG pattern occur in numerous cardiac abnormalities, including cardiac rhythm disturbances (such as atrial fibrillation and ventricular tachycardia), inadequate coronary artery blood flow (such as myocardial ischemia and myocardial infarction), and electrolyte disturbances (such as hypokalemia and hyperkalemia).
A number of tests may help with diagnoses including: electrocardiogram, cardiac stress testing, coronary computed tomographic angiography, and coronary angiogram, among others.

Hypokalemia

hypokalaemialow blood potassiumhypokalemic
Changes in the normal ECG pattern occur in numerous cardiac abnormalities, including cardiac rhythm disturbances (such as atrial fibrillation and ventricular tachycardia), inadequate coronary artery blood flow (such as myocardial ischemia and myocardial infarction), and electrolyte disturbances (such as hypokalemia and hyperkalemia).
Low levels may also be suspected based on an electrocardiogram (ECG).

Drug-induced QT prolongation

QT prolongationQT interval prolongationQTc prolongation
It is an electrical disturbance which can be seen on an electrocardiogram (ECG).

Holter monitor

Ambulatory ECG monitoringambulatory electrocardiogram monitoringHolter
Continuous monitoring can be conducted by using Holter monitors, internal and external defibrillators and pacemakers, and/or biotelemetry.
In medicine, a Holter monitor (often simply Holter) is a type of ambulatory electrocardiography device, a portable device for cardiac monitoring (the monitoring of the electrical activity of the cardiovascular system) for at least 24 to 48 hours (often for two weeks at a time).

Ventricular tachycardia

polymorphic ventricular tachycardiapulseless ventricular tachycardiamonomorphic ventricular tachycardia
Changes in the normal ECG pattern occur in numerous cardiac abnormalities, including cardiac rhythm disturbances (such as atrial fibrillation and ventricular tachycardia), inadequate coronary artery blood flow (such as myocardial ischemia and myocardial infarction), and electrolyte disturbances (such as hypokalemia and hyperkalemia).
Diagnosis is by an electrocardiogram (ECG) showing a rate of greater than 120 beats per minute and at least three wide QRS complexes in a row.

Artificial cardiac pacemaker

pacemakerartificial pacemakerpacemakers
Continuous monitoring can be conducted by using Holter monitors, internal and external defibrillators and pacemakers, and/or biotelemetry. Among other things, an ECG can be used to measure the rate and rhythm of heartbeats, the size and position of the heart chambers, the presence of any damage to the heart's muscle cells or conduction system, the effects of heart drugs, and the function of implanted pacemakers.
The rescuer selects the pacing rate, and gradually increases the pacing current (measured in mA) until electrical capture (characterized by a wide QRS complex with a tall, broad T wave on the ECG) is achieved, with a corresponding pulse.

Shortness of breath

dyspnearespiratory distressdyspnoea
An electrocardiogram and cardiac enzymes are important both for diagnosis and directing treatment.

Cardiac stress test

exercise stress teststress testcardiac stress tests
To measure the heart's response to the stress the patient may be connected to an electrocardiogram (ECG); in this case the test is most commonly called a cardiac stress test but is known by other names, such as exercise testing, stress testing treadmills, exercise tolerance test, stress test or stress test ECG.

Tricyclic antidepressant overdose

antidepressant overdosetricyclic overdose
An electrocardiogram (ECG) should be included in the assessment when there is concern of an overdose.

Syncope (medicine)

syncopefaintingfainted
A medical history, physical examination, and electrocardiogram (ECG) are the most effective ways to determine the underlying cause.

PR interval

PRPR-short PR
This analysis calculates features such as the PR interval, QT interval, corrected QT (QTc) interval, PR axis, QRS axis, rhythm and more.
In electrocardiography, the PR interval is the period, measured in milliseconds, that extends from the beginning of the P wave (the onset of atrial depolarization) until the beginning of the QRS complex (the onset of ventricular depolarization); it is normally between 120 and 200ms in duration.

Automated ECG interpretation

automated interpretation
Most modern ECG machines include automated interpretation algorithms.
Automated ECG interpretation is the use of artificial intelligence and pattern recognition software and knowledge bases to carry out automatically the interpretation, test reporting, and computer-aided diagnosis of electrocardiogram tracings obtained usually from a patient.

Electrode

electrodescathodemicroelectrode
Electrocardiography is the process of producing an electrocardiogram (ECG or EKG), a recording – a graph of voltage versus time – of the electrical activity of the heart using electrodes placed on the skin.

Hypertrophic cardiomyopathy

hypertrophic obstructive cardiomyopathyAsymmetric septal hypertrophyFeline hypertrophic cardiomyopathy
Hypertrophic cardiomyopathy screening may also be considered in adolescents as part of a sports physical out of concern for sudden cardiac death.
Diagnosis often involves an electrocardiogram, echocardiogram, and stress testing.

Cardiac cycle

heartbeatheart beatventricular systole
In this way, the overall magnitude and direction of the heart's electrical depolarization is captured at each moment throughout the cardiac cycle.
In an electrocardiogram, electrical systole initiates the atrial systole at the P wave deflection of a steady signal; and it starts contractions (systole).

Driven right leg circuit

Driven Right Legright leg driver
Biological signal amplifiers such as ECG (Electrocardiogram) EEG (Electroencephalogram) or EMG circuits measure very small electrical signals emitted by the body, often as small as several micro-volts (millionths of a volt).

Defibrillation

defibrillatordefibrillatorsdefibrillate
Continuous monitoring can be conducted by using Holter monitors, internal and external defibrillators and pacemakers, and/or biotelemetry.
They are used in conjunction with an electrocardiogram, which can be separate or built-in.

Clinical cardiac electrophysiology

Electrophysiological interventionselectrophysiology
These studies are performed to assess arrhythmias, elucidate symptoms, evaluate abnormal electrocardiograms, assess risk of developing arrhythmias in the future, and design treatment.

Atrial flutter

flutteratrial flutter (AFl)
An esophageal lead avails for a more accurate differentiation between certain cardiac arrhythmias, particularly atrial flutter, AV nodal reentrant tachycardia and orthodromic atrioventricular reentrant tachycardia.
Atrial flutter is characterized by a sudden-onset (usually) regular abnormal heart rhythm on an electrocardiogram (ECG) in which the heart rate is fast.

Einthoven's triangle

Einthoven's circle is an imaginary formation of three limb leads in a triangle used in electrocardiography, formed by the two shoulders and the pubis.

Pulseless electrical activity

Electromechanical dissociationPEApulseless electrical activity (PEA)
An ECG does not equate with mechanical pumping activity of the heart, for example, pulseless electrical activity produces an ECG that should pump blood but no pulses are felt (and constitutes a medical emergency and CPR should be performed).
Pulseless electrical activity (PEA) refers to cardiac arrest in which the electrocardiogram shows a heart rhythm that should produce a pulse, but does not.