Sat27November0445PM 37

Which of the following clinical conditions are associated with changes to the electrocardiograph?

True / False

Hypothermia and bradycardia, J waves and a shortened Q-T interval Incorrect answer selected

Hypokalaemia and a prolonged Q-T interval Incorrect answer selected

Hypoparathyroidism and a prolonged Q-T interval Correct

Hyperkalaemia and absent P waves Correct

Pericarditis and inverted T waves Correct

Explanation

The Q-T interval is measured from the first deflection of the QRS complex to the end of the T wave.

The Q-T interval is increased (prolonged) with

Hypocalcaemia

Myocarditis

Ischaemic heart disease

Hypothermia and

Following antiarrhythmic drugs.

It is decreased (shortened) by

Hypercalcaemia

Digoxin

Inotropes and

Elevated catecholamine levels.

Hypoparathyroidism is associated with hypocalcaemia thus the Q-T interval may be prolonged.

Hyperkalaemia is associated with tall or peaked T waves, widened QRS complexes, and the loss of R and P waves.

Hypokalaemia may lengthen the Q-T interval and is also associated with prominent U waves, flattened or inverted T waves, ST depression and a prolonged P-R interval.

In pericarditis there is concave (upwards) S-T elevation in all the leads except aVR. The S-T segments gradually become isoelectric and the T waves invert after two to three weeks eventually reverting to normal.

Hypothermia is associated with J waves (towards the end of the QRS) and a prolonged Q-T interval.

In addition a variety of arrhythmias have been seen, ranging from sinus bradycardia and atrial fibrillation to ventricular fibrillation and cardiac arrest.

Answer Statistics

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Average score: 57.77%

Times answered: 233