The end of the T-wave in ECG mark the

Options

A. beginning of Ventricular systole
B. end of Ventricular systole
C. beginning of atrial diastole
D. end of atrial diastole

Answer

To determine what the end of the T-wave in an ECG marks, we can analyze the options provided step by step.

### Step-by-Step Solution:

1. **Understanding the T-Wave**: The T-wave in an ECG represents the repolarization of the ventricles. It occurs after the QRS complex, which indicates ventricular depolarization and contraction.

**Hint**: Remember that the T-wave is associated with the recovery phase of the ventricles.

2. **Evaluating Option 1 - Beginning of Ventricular Systole**: This option states that the end of the T-wave marks the beginning of ventricular systole. This is incorrect because ventricular systole begins with the QRS complex, not at the end of the T-wave.

**Hint**: Recall that ventricular systole is associated with the contraction of the ventricles, which is reflected in the QRS complex.

3. **Evaluating Option 2 - End of Ventricular Systole**: This option suggests that the end of the T-wave marks the end of ventricular systole. This is correct because the T-wave represents the repolarization of the ventricles, which occurs after they have contracted (during systole).

**Hint**: Consider the sequence of electrical events in the heart; the T-wave follows the contraction phase.

4. **Evaluating Option 3 - Beginning of Atrial Diastole**: This option states that the end of the T-wave marks the beginning of atrial diastole. This is incorrect because atrial diastole occurs independently of the T-wave and is not directly marked by it.

**Hint**: Atrial diastole is related to the relaxation of the atria, which happens at a different point in the cardiac cycle.

5. **Evaluating Option 4 - End of Atrial Diastole**: This option suggests that the end of the T-wave marks the end of atrial diastole. This is also incorrect, as the end of atrial diastole is marked by the P-wave, which indicates atrial depolarization.

**Hint**: The P-wave represents the electrical activity associated with the atria contracting, which is separate from the T-wave.

### Conclusion:
The correct answer is **Option 2 - End of Ventricular Systole**. The end of the T-wave in an ECG marks the completion of the ventricular contraction phase.