ECG Full Form

Latest: NEET 2024 Paper Analysis

Recommended: NEET Rank Predictor 2024

See more: NEET Result 2024

ECG

ECG is the short form of Electrocardiography. It is the test by which a doctor can identify the problem in heart rhythm and it’s activity so as to provide better and accurate treatment to the patient’s problem. The sensors of the machine are attached to the skin of the patient which record the heart’s electrical signal produced with every beat. The cardiologist suggests the patient for ECG if he finds any irregularities in the heart rhythm. It is done when a patient suffers from arrhythmias, coronary heart disease, heart attack, chest pain, heart palpitations, shortness of breath, fluctuating high or low pulse rate.

Interpretation of Electrocardiograph

Electrocardiograph is the machine which measures the heart’s electrical conduction. The theory of ECG includes;

• Heart’s depolarisation towards the electrodes having positive charge which produce positive deflection
• Heart’s depolarisation towards the electrode having negative charge (away from electrode having positive charge) which produces negative deflection
• Heart’s repolarisation towards the electrodes having positive charge which produce negative deflection
• Heart’s repolarisation towards the electrodes having negative charge (away from electrodes having positive charge) which produce positive deflection

Normal heart rhythm produces four waves and they are; P wave (represents depolarisation of arteries), QRS complex wave (represents depolarisation of ventricles), T wave (represents repolarisation of ventricles) and U wave (represents repolarisation of papillary muscles). Any abnormality in the heart’s structure or its surroundings causes change in these four waves patterns.

ECGs are recorded on the graph or the grid in which the x-axis (horizontal) represents the time per second while the y-axis (vertical) represents voltage in millivolt (1mm representing 40 milliseconds on horizontal axis and 0.1 millivolts on vertical axis).

Description of waves

P wave: The duration of P wave is less than 80 millisecond which represents the atrial depolarization which spreads from SA node and reaches towards AV node as well as from right atrium towards left atrium.

PR or PQ interval: The duration of PR interval lasts in a range of 120 millisecond to 200millisecond and is measured from P wave beginning till QRS complex wave beginning. This interval specifies the time taken by the electrical impulse to travel from SA (sinoatrial) node through atrioventricular node (AV node).

QRS complex wave: The duration of QRS complex wave lies in a range of 80 to 100 milliseconds which represents the depolarization of ventricles (right and left ventricles). They have more amplitude as compared to P waves as the ventricles have large muscle mass than the atria.

J point: It is the point where the ST segment begins with the ending of QRS complex waves.

ST segment: This segment unites the T wave with QRS complex and depicts the period of depolarization of ventricles and isoelectric during which ventricular systolic i.e. Contraction of ventricles takes place.

T wave: The duration of T wave is 160 milliseconds in which the ventricular contractile fibres get repolarized and is a dome shaped wave.

Corrected QT interval: The time for this interval is less than 440 milliseconds which begins from the QRS complex and ends with the T wave.

U wave: It is caused by interventricular septum repolarisation with low amplitude and this wave is usually negligible.

Relationship between action potential and Electrocardiograph

The action potential is associated with the charged particles (sodium, potassium, calcium and chlorine) passage across the cardiac cell membrane. The movement of these charged ions across the membrane results in the electrical signals production which are measured and recorded at the body’s surface through an instrument called an Electrocardiograph and the record obtained is known as Electrocardiogram or ECG.

Types of ECG tests

It is of two types that a doctor can suggest;

• Holter monitor: This checks the heart’s electrical activity for 24 hours a day or 1-2 days. This is suggested by the doctor when insufficient blood flows to the heart or you have heart palpitations or abnormal heart rhythm. It is a painless process.

• Event monitor: This is suggested by the doctor when you have signs and symptoms only now and then i.e. for a shorter period of time.

Performance of ECG 

• The doctor or the lab technician who is doing ECG will ask you to lie down on a bed
• Then he cleans the patient’s chest, arms and legs
• Now he will attach the small patched electrodes of the machine to the above mentioned areas of the patient’s body
• These electrodes are in turn attached to the machine which records the electrical signal of the heart into wavy lines that are printed on paper
• Finally the doctor read the results and diagnosed the patient

You have to remain calm, warm and still during the test. The person who is performing the test may also ask the patient to hold his breath for a few seconds. There is no risk in performing this ECG test but you have to cooperate with the doctor.

Conclusion

ECG or Electrocardiograph is the test which records the heart’s electrical activity. It is used when a person have abnormal heart rate, or a patient suffers from the symptoms like dizziness and weakness, myocardial ischemia, coronary artery disease, cardiac arrhythmias, electrolyte imbalance, ventricular tachycardia chest pain and many more. ECG is done with the help of small patched electrodes which is placed on arms, chest and legs of the patient which in turn gives the graph which is then recorded on the paper. The waves which depict the ECG readings are P wave, QRS complex wave, T wave and U wave.