9 An increase in the heart rate would cause the Pwave to Pwa

9.   An increase in the heart rate would cause the P-wave to P-wave distance to:
1)   Increase
2)   Decrease      
3)   Stay the same
Explain your choice

Solution

9. Answer: P-wave to P-wave distance, (i.e, PP interval) decreases with increase in heart rate.

Explanation: Heart rate amounts to number of heart beats per minute. P wave on the ECG chart denotes atrial depolarization and the P-P interval is the interval between the two P waves. This interval is measures in terms of millimeters on ECG paper. In a rthymic heart, PP interval (atricular rate) is equal to RR interval (ventricular rate), and both are used to measure the heart beat. On ECG paper, these waves; P-wave, QRS wave are seperated by boxex. As the heart beats faster, the ECG ocsillations are faster and the distance between one P-wave to another P-wave decreases, or the boxes between the two consecutive waves decreases.