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 ECGs, a person is connected to the machine with three electrical leads

Answer

To solve the question "Choose the correct statement," we will analyze each option provided and determine which one is accurate based on our understanding of ECG (electrocardiogram) readings.

### Step-by-Step Solution:

1. **Analyze Option A**: "The T wave in an ECG represents excitation of ventricles."
- The T wave actually represents the relaxation of the ventricles, not their excitation. Therefore, this statement is **incorrect**.

2. **Analyze Option B**: "The sum of P and T waves in a given time period can determine the heartbeat rate of the individual."
- The heart rate is determined by the QRS complex, not the sum of the P and T waves. Thus, this statement is also **incorrect**.

3. **Analyze Option C**: "The end of the P wave marks the end of the systole."
- The P wave represents the excitation of the atria leading to atrial systole, but it does not mark the end of systole. Therefore, this statement is **incorrect**.

4. **Analyze Option D**: "In a standard ECG, a person is connected to the machine with three electrical leads."
- This statement is accurate. In a standard ECG setup, three leads (Lead I, Lead II, and Lead III) are used to connect the patient to the ECG machine. Thus, this statement is **correct**.

### Conclusion:
The correct statement is **Option D**: "In a standard ECG, a person is connected to the machine with three electrical leads."

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