Question

The flat horizontal line in between the waves of ECG represents time when

• A. there is no mechanical activity in the heart but there is electrical activity in the heart
• B. there is no electrical activity in the heart but there is mechanical activity in the heart
• C. there is no mechanical activity in the heart and there is no electrical activity in the heart
• D. there is mechanical activity in the heart and there is electrical activity in the heart

Answer 1

Answer: (B)

Electrocardiogram ECG has P wave, QRS complex and T wave. The P wave is an upward wave and indicates atrial depolarisation, QRS complex indicates ventricular depolarization. T wave is an upward wave and indicates ventricular repolarisation.The flat horizontal line is called the isoelectric line. There is no electrical activity, but there will be mechanical activity. Example: ST segment indicates atrial contraction.