Question

list one possible cause for each of the following cardiac abnormalities.

abnormal t waves

abnormal p-r interval

Answer 1

Abnormal t waves:

• T wave represents repolarization of ventricles in electrocardiography and the interval from the beginning of QRS complex to the apex of T wave is termed as 'absolute refractory period' and the remaining half of T wave is termed as 'relative refractory period'.
• Changes in T wave like low amplitude and inverted T waves are called abnormal T waves, which causes cardiac and non-cardiac conditions.
• A possible cause of abnormal T wave is hyperkalaemia, which means high level of potassium in the body which results in narrow-based and peaked T wave. It thereby increases myocardial potassium channels. So, it causes changes in normal T wave resulting in abnormal T wave.

Abnormal p-r interval:

• P-r interval is the period which extends from the beginning of P wave to the beginning of QRS complex. It is sometimes referred as PQ interval.
• Alterations in p-r interval due to some physiological reasons leads to abnormal p-r interval and can cause heart block.
• One of the possible cause for abnormal p-r interval is atrioventricular reentrant tachycardia, which means a condition of abnormal fast heartbeat rhythm. It causes heart block.

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