Final answer:
A second-degree Mobitz type I AV block, also known as Wenckebach block, is diagnosed by observing the electrocardiogram (ECG) readings. The pattern is characterized by a progressive lengthening of the PR interval until a QRS complex is dropped.
Step-by-step explanation:
A second-degree Mobitz type I AV block, also known as Wenckebach block, is diagnosed by observing the electrocardiogram (ECG) readings. In this type of block, there is a progressive lengthening of the PR interval until a QRS complex is dropped. The dropped QRS complex indicates a failed conduction of the electrical impulse from the atria to the ventricles. This pattern can be seen in the ECG as P waves followed by a missing QRS complex, followed by a normal P wave-QRS complex interval. A 2nd degree Mobitz type I AV block is a common conduction abnormality and can be easily diagnosed through ECG analysis.