QT interval
The best method to test the correct functioning of the heart's electrical signals is to take an ECG. Electro cardiogram or ECG is a very popular method of measuring the electrical activity of heart. In diagnosing all cardiovascular problems ECG is the main test out of many others to correctly assess the situation.
Heart is a main organ that pumps blood throughout the body. The electrical signals that make blood clot in brain the heart contract and work properly are located at the atrial node of the heart. This part is called the pacemaker. ECG makes a record of these electrical signals. A typical consists of a wave like patterns. A singular wave of an ECG can be seen above in the diagram. One whole heart cycle of one beat consists of two waves namely the Q wave and the T wave, as shown in the diagram. In cardiology, the ECG is interpreted in terms of the QT interval. The time taken to start the Q wave and to end the T wave is known as the QT interval. It symbolizes the polarization and the depolarization of both the ventricles. A long QT interval is a pointer for ventricular tachyarrhythmia and indicates a risk for abrupt death.
The QT interval is dependent on the rate of heart as is obvious. The faster the heart is beating the shorter will the QT interval. Generally the readings of a normal QT interval are improved to observe any risks of ventricular arrhythmia. Normally the corrections of these intervals are done through computers. The clinical importance of QT intervals is great especially in cardiology diseases like long QT syndrome. The measurement of QT varies from individual to individual. This is because every person's cardiogram is different and the end of the T wave is not always clear. Sometimes it just gradually fuses with the baseline. Therefore the methods for measurement of this interval are different for example superimposed median beat method is used due to the convenience of fast computers to measure ECG in 12 channels simultaneously. The other method normally used is called the threshold method.
A normal QT interval has a wide range and cannot be classified as a rigid standard. However, many research studies have shown that a normal QT interval for men is equal to or less than 430ms and equal to or less than 450ms for women. The intervals are coming too long or too short from these standards then the risk of getting ventricular arrhythmias is great. Sometimes, it comes as a genetic problem such as short or long QT syndrome. In this genital disease the re-polarization of the heart is delayed because of a defect in genes. Other than these intervals are also affected by adverse drug reactions that affect the working of a heart. Drugs like haloperidol, ziprasodone etc are able to delay the intervals. Also pathological conditions can affect the intervals in an ECG. Low functioning of the thyroid gland, hypocalcaemia etc can lead to ventricular dysrhythmias.
The best method to test the correct functioning of the heart's electrical signals is to take an ECG. Electro cardiogram or ECG is a very popular method of measuring the electrical activity of heart. In diagnosing all cardiovascular problems ECG is the main test out of many others to correctly assess the situation.
Heart is a main organ that pumps blood throughout the body. The electrical signals that make blood clot in brain the heart contract and work properly are located at the atrial node of the heart. This part is called the pacemaker. ECG makes a record of these electrical signals. A typical consists of a wave like patterns. A singular wave of an ECG can be seen above in the diagram. One whole heart cycle of one beat consists of two waves namely the Q wave and the T wave, as shown in the diagram. In cardiology, the ECG is interpreted in terms of the QT interval. The time taken to start the Q wave and to end the T wave is known as the QT interval. It symbolizes the polarization and the depolarization of both the ventricles. A long QT interval is a pointer for ventricular tachyarrhythmia and indicates a risk for abrupt death.
The QT interval is dependent on the rate of heart as is obvious. The faster the heart is beating the shorter will the QT interval. Generally the readings of a normal QT interval are improved to observe any risks of ventricular arrhythmia. Normally the corrections of these intervals are done through computers. The clinical importance of QT intervals is great especially in cardiology diseases like long QT syndrome. The measurement of QT varies from individual to individual. This is because every person's cardiogram is different and the end of the T wave is not always clear. Sometimes it just gradually fuses with the baseline. Therefore the methods for measurement of this interval are different for example superimposed median beat method is used due to the convenience of fast computers to measure ECG in 12 channels simultaneously. The other method normally used is called the threshold method.
A normal QT interval has a wide range and cannot be classified as a rigid standard. However, many research studies have shown that a normal QT interval for men is equal to or less than 430ms and equal to or less than 450ms for women. The intervals are coming too long or too short from these standards then the risk of getting ventricular arrhythmias is great. Sometimes, it comes as a genetic problem such as short or long QT syndrome. In this genital disease the re-polarization of the heart is delayed because of a defect in genes. Other than these intervals are also affected by adverse drug reactions that affect the working of a heart. Drugs like haloperidol, ziprasodone etc are able to delay the intervals. Also pathological conditions can affect the intervals in an ECG. Low functioning of the thyroid gland, hypocalcaemia etc can lead to ventricular dysrhythmias.
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