Final answer:
The P wave is present in all beats except one, with narrow QRS complexes indicating a regular rhythm at 70 beats per minute with a premature junctional beat. A PJC typically introduces a small variation in the normal rhythmic pattern on an ECG.
Step-by-step explanation:
The correct statement based on the provided ECG description of Normal Sinus Rhythm with a Premature Junctional Contraction (PJC) is A. A Premature Junctional Contraction is an early heartbeat that starts in the part of the heart known as the atrioventricular junction. It’s characterized by an absent or inverted P wave, or a P wave that comes after the QRS complex, and the presence of a narrow QRS complex. The rest of the ECG shows a normal sinus rhythm, which means the P wave is present and followed by a QRS complex in all other beats, indicating a regular rhythm, generally at a rate between 60-100 beats per minute. The presence of one PJC would mean that one beat occurs earlier than expected, which is not a sign of a significant underlying disorder if it occurs infrequently and in absence of heart disease.
A comprehensive look at an ECG can reveal information about the heart’s electrical activity and rhythm. The P wave indicates atrial depolarization, the QRS complex indicates ventricular depolarization, and the T wave indicates ventricular repolarization. In a normal sinus rhythm, there is a consistent pattern of P wave followed by a QRS complex, indicating the normal sequence of electrical activity and muscle contractions from the atria to the ventricles. Regularity, rate, and the morphology of the complexes and intervals on an ECG helps in diagnosing various arrhythmias or irregularities.