MICROANATOMY

Detailed explanation-1: -The P wave and PR segment is an integral part of an electrocardiogram (ECG). It represents the electrical depolarization of the atria of the heart. It is typically a small positive deflection from the isoelectric baseline that occurs just before the QRS complex.

Detailed explanation-2: -In sinus rhythm, the observed Ta wave in the PR segment represents the early part of atrial repolarization. Generally, part of the Ta wave is superimposed onto the QRS complex and the ST-segment (4).

Detailed explanation-3: -Final answer: Depolarization of atria is represented by P-wave.

Detailed explanation-4: -’P’ wave is the first wave in an ECG and is a positive wave. It indicates the activation of the SA nodes. ‘T’ wave too is a positive wave and is the final wave in an ECG though sometimes an additional U wave may be seen. It represents ventricular relaxation.

Detailed explanation-5: -Atrial depolarization is reflected by the P wave, and ventricular depolarization is reflected by the QRS complex, whereas the T wave reflects ventricular repolarization, see Figure 6.10. Atrial repolarization cannot usually be discerned from the ECG since it coincides with the much larger QRS complex.