Body Fluids and Circulation Question 51
51. Match the Column-I with Column-II. [2019]
Column-I Column-II
(a) P-wave
(i) Depolarisation of ventricles
(b) QRS complex (ii) Repolarisation of ventricles
(c) $T$ - wave (iii) Coronary ischemia
(d) Reduction in the size of (iv) Depolarisation of T-wave atria (v) Repolarisation of atria
Show Answer
Answer : a
Hints & Solutions
(a) Electrocardiogram is a diagnostic tool, used to assess the electrical and muscular functions of the heart. It consists of waveform components which indicate electrical events during one heart beat. These waveforms are labelled P, Q, R, S, T and U.
- $\quad P$ wave indicates atrial depolarisation i.e. that the atria are contracting, pumping blood into the ventricles.
- The QRS complex represents ventricular depolarisation and contraction.
- T wave is upwards waveform representing ventricular repolarisation. The normal $T$ wave is slightly asymmetric with a steeper downward slope. Reduction in the size of $T$ wave represents insufficient supply of oxygen i.e. coronary ischemia. Coronary ischemia is an intermediate condition in coronary artery disease during which the heart tissue is slowly or suddenly starved of oxygen and other nutrients.
