Final answer:
The most likely diagnosis based on the given ECG is Sinus Rhythm with Premature Junctional Contractions (B).
Step-by-step explanation:
The most likely diagnosis based on the given ECG is Sinus Rhythm with Premature Junctional Contractions (B).
Looking at the ECG, we can see an abnormal electrical pattern prior to the QRS complexes, which indicates the presence of premature junctional contractions. These contractions occur when the electrical signal that normally originates from the sinus node is interrupted or overridden by an ectopic focus in the junctional region of the heart.
Other options like Sinus Bradycardia (A), Sinus Tachycardia (C), and Atrial Fibrillation (D) do not match the characteristics observed in the given ECG.