Choose the correct statement:

Options

A. The T-wave in an ECG represents excitation of ventricles
B. The sum of P and T waves in a given time period can determine the heart beat rate of an individual
C. The end of the P Wave marks the end of the systole
D. In a standard ECG, a person is connected to the machine with three electrical leads

Answer

To solve the question "Choose the correct statement," we will analyze each of the provided statements regarding the electrocardiogram (ECG) and its components.

### Step-by-Step Solution:

1. **Analyze the First Statement:**
- The first statement claims that "the T wave in an ECG represents excitation of ventricles."
- **Explanation:** The T wave actually represents the repolarization (relaxation) of the ventricles, not their excitation (depolarization). Therefore, this statement is **incorrect**.

2. **Analyze the Second Statement:**
- The second statement states that "the sum of P and T wave in a given time period can determine the heartbeat rate of an individual."
- **Explanation:** The heartbeat rate is determined by the intervals between the P wave and QRS complex, not by the sum of the P and T waves. The P wave represents atrial depolarization, while the QRS complex represents ventricular depolarization. Thus, this statement is also **incorrect**.

3. **Analyze the Third Statement:**
- The third statement claims that "the end of V wave represents the end of the systole."
- **Explanation:** The V wave is not a standard term in ECG interpretation. The P wave marks the beginning of atrial systole, while the end of systole is not represented by the V wave. Therefore, this statement is **incorrect**.

4. **Analyze the Fourth Statement:**
- The fourth statement indicates that "in a standard ECG, a person is connected to a machine with three electrical leads."
- **Explanation:** This statement is correct. A standard ECG does involve connecting a patient to a machine using multiple leads (often three or more) to record the electrical activity of the heart. Thus, this statement is **correct**.

### Conclusion:
The correct statement is the fourth one, which describes the setup of a standard ECG.

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