In general, the normal adult PR interval is 0.12~0.2 seconds, and the PR interval in the elderly can be slightly prolonged, but not more than 0.22 seconds.
PR interval represents the time from the beginning of atrial depolarization to the beginning of ventricular depolarization. PR interval is related to age and heart rate, the younger the age and the faster the heart rate, the PR interval will be shortened accordingly. In general, the normal adult PR interval is 0.12-0.2 seconds, the elderly and bradycardia people, PR interval can be slightly prolonged, but the longest does not exceed 0.22 seconds.
PR interval prolongation is common in atrioventricular block, the patient’s electrocardiogram is characterized by PR interval >0.20 seconds, which can be specifically divided into one degree, two degrees of type I, two degrees of type II, and three degrees of atrioventricular block; shortening of PR interval is common in preexcitation syndrome, short P-R syndrome, and the electrocardiogram of preexcitation syndrome is characterized by PR interval <0.12 seconds, QRS interval ≥ 0.12 seconds, PJ interval <0.26 seconds.
If the patient’s electrocardiogram shows that the PR interval is not within the normal range, it is recommended that he or she go to the hospital and be treated under a physician’s evaluation to avoid the prolongation of pathologic factors such as arrhythmia, acute pericarditis, and hyperkalemia.