ECG, EEG, NCS

ECG

Electrocardiography is the process of producing an electrocardiogram (ECG or EKG[a]), a recording – a graph of voltage versus time – of the electrical activity of the heart using electrodes placed on the skin. These electrodes detect the small electrical changes that are a consequence of cardiac muscle depolarization followed by repolarization during each cardiac cycle (heartbeat). 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).

In a conventional 12-lead ECG, ten electrodes are placed on the patient’s limbs and on the surface of the chest. The overall magnitude of the heart’s electrical potential is then measured from twelve different angles (“leads”) and is recorded over a period of time (usually ten seconds). In this way, the overall magnitude and direction of the heart’s electrical depolarization is captured at each moment throughout the cardiac cycle.

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.

EEG

An electroencephalogram (EEG) is a test used to find problems related to electrical activity of the brain. An EEG tracks and records brain wave patterns. Small metal discs with thin wires (electrodes) are placed on the scalp, and then send signals to a computer to record the results.

what is an EEG?

An electroencephalogram (EEG) is a test used to evaluate the electrical activity in the brain. Brain cells communicate with each other through electrical impulses. An EEG can be used to help detect potential problems associated with this activity.

An EEG tracks and records brain wave patterns. Small flat metal discs called electrodes are attached to the scalp with wires. The electrodes analyze the electrical impulses in the brain and send signals to a computer that records the results.

The electrical impulses in an EEG recording look like wavy lines with peaks and valleys. These lines allow doctors to quickly assess whether there are abnormal patterns. Any irregularities may be a sign of seizures or other brain disorders.

An EEG is used to detect problems in the electrical activity of the brain that may be associated with certain brain disorders. The measurements given by an EEG are used to confirm or rule out various conditions, including:

NCS-Nerve conduction Study

A nerve conduction velocity (NCV) test — also called a nerve conduction study (NCS) — measures how fast an electrical impulse moves through your nerve. NCV can identify nerve damage. During the test, your nerve is stimulated, usually with electrode patches attached to your skin.

MNerve conduction studies are done to: Find and evaluate damage to all the nerves that lead away from the brain and spinal cord to the smaller nerves that branch out from them. Help diagnose nerve disorders, such as carpal tunnel syndrome or Guillain-Barré syndrome.

2D-ECHO

Abstract. 4D (3D spatial+time) echocardiography is gaining widespread acceptance at clinical institutions for its high temporal resolution and relatively low cost. We describe a novel method for computing dense 3D myocardial motion with high accuracy.

2D Echocardiography or 2D Echo of heart is a test in which ultrasound technique is used to take pictures of heart. It displays a cross sectional ‘slice’ of the beating heart, showing chambers, valves and the major blood vessels of heart.