Distinguish between the ECG trace of the patient with hypokalemia and the patient with hyperkalemia.

Outline the events that occur within the heart that correspond to the QRS complex.

Severe hypokalemia can lead to ventricular fibrillation. Describe the medical response to ventricular fibrillation.

Sometimes hyperkalemia occurs as a body tries to respond to low blood pH. State the normal range of blood pH in the human body.

Explain how low blood pH causes hyperventilation (rapid breathing).

a. hypokalemia has a flat T-wave whereas hyperkalemia has a heightened T-wave OWTTE
OR
hypokalemia S-T interval longer Accept vice versa

b. hypokalemia has narrower/faster QRS complex compared to hyperkalemia  Accept vice versa

c. hypokalemia trace/baseline «overall» lower than hyperkalemia Accept vice versa

a. arrival of signal at AV node 

b. transmission via conducting fibres/bundle of His/Purkinje fibres 

c. ventricles depolarize 

d. atrioventricular valves close
OR
semilunar valves open 

e. ventricular systole/contraction 

f. contraction begins at apex/base

a. use a defibrillator 

b. place electrodes on exposed chest of victim 

c. in a line with the heart in the middle of a diagonal line between the two paddles 

d. the device determines whether fibrillation is happening 

e. if it is, an electric discharge is given off to restore a normal heart rhythm

around 7.4 or 7.35 to 7.45

a. increased CO₂ lowers blood pH 

b. chemoreceptors in carotid/aorta detect lower pH 

c. signal/impulses to medulla «oblongata»
OR
signal/impulses to respiratory centre 

d. «from medulla/respiratory centre» to intercostal muscles/diaphragm 

e. ventilation rate increase occurs to expel CO₂