The P and T wave are in shape of a curve while the QRS complex is in straight lines. What is the reason this is happening?


1 Answer 1


P wave represents atrial depolarization (hence atrial contraction).

Atrial depolarization takes only a split second, therefore its corresponding wave will be smooth and rounded.

Variations from this shape could be consequences of various heart diseases: for example,a spiked P wave is called P pulmonale and suggests right atrial enlargement.

T wave represents ventricular repolarization: a normal T wave looks like an

upright low amplitude broad hump following the QRS complex.

Abnormalities in T wave could be the signs for multiple heart diseases, varying from myocardial ischemia to hyperkalemia.

In particular, peaked T waves suggest an hyperkalemia diagnosis.

T wave abnormalities are well documented here

The QRS complex corresponds to ventricular depolarization, which is faster and more intense than atrial or ventricular repolarization: hence a normal QRS complex is peaked.

In conclusion, P wave and T wave are rounded because these correspond to low-intensity electrical events while the QRS complex is provoked by an intense electrical event.


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