$ECG$ records:

$T$-wave represents:

Arrange and select the following events in the correct sequence during the measurement of blood pressure by a sphygmomanometer.
$i.$ Pulsatile sound disappears.
$ii.$ Cuff is inflated to block the brachial artery by external pressure.
$iii.$ First pulsatile sound is heard indicating systolic pressure.
$iv.$ Pressure in the cuff is slowly lowered.
$v.$ Cuff is wrapped tightly around the upper arm.

Which of the following values indicates hypertension?

In the following diagrammatic representation of a standard $ECG$,the '$T$' wave represents:

$QRS$ complex is related to