Question

In a standard ECG, which one of the following alphabets is the correct representation of the respective of the human heart?

• A. R - repolarisation of ventricles
• B. S - start of systole
• C. T - end of diastole
• D. P - depolarization of the atria

Answer 1

Answer: (D)

P - depolarization of the atria

The P wave represents the wave of depolarization that spreads from the SA node throughout the atria, and is usually 0.08 to 0.1 seconds in duration. The QRS complex represents ventricular depolarization. The duration of the QRS complex is normally 0.06 to 0.1 seconds. ST segment following the QRS is the time at which the entire ventricle is depolarized. The ST segment is important in the diagnosis of ventricular ischemia or hypoxia. The T wave represents ventricular repolarization and is longer in duration than depolarization. The Q-T interval represents the time for both ventricular depolarization and repolarization to occur, and therefore roughly estimates the duration of an average ventricular action potential.