ELECTRO CARDIOGRAPHY – ECG

ECG is the process of recording electrical activity of heart over a period of time by placing electrodes on the skin of chest and limbs of a patient. The electrodes measure tiny changes in electrical activity of the heart muscles during each heartbeat.

REPRESENTATION OF NORMAL ECG

Depolarization in the context of biology refers to sudden change in the cells when the cells are subjected to dramatic electric changes. Most cells maintain a negative environment compared to the exterior surrounding. In the process of depolarization in the cell the negative internal charge becomes positive for a brief period.

 ECGof a 26 year old person

The change from negative to positive in the internal environment of cell allows transmission of electric impulses within a cell or between cells. The communicative function of polarization is essential for the function of many cells in the organism.

ECG has 12 electrodes. 10 electrodes are placed on the skin of chest and limbs. The overall magnitude of electrical potential is recorded from 12 different points. The heart’s depolarization is captured throughout the cardiac cycle.

ELECTROCARDIOGAPHY

During each heartbeat in a healthy person depolarization takes place in a progressive way. The orderly pattern of depolarization gives rise to ECG tracing. ECG can be used to study the rate and rhythm of heart beats, the size and position of heart chambers, the effect of any cardiac drugs, presence of any damage to heart muscles and the performance of pacemaker in the body.

ECG tests are conducted to diagnose heart attack, blocks in arteries, extra heart sound, cardiac murmur, fainting, fit of a person and to study the effect of heart medication.

A heartbeat between 60 and 100 means the person has normal heartbeat. Heartbeat less than 60 is said to be resting heartbeat. When heartbeat goes above 100 it is tachycardiac. Athletes having heartbeat less than 60 is normal.