Which of the following clients is at a higher risk of developing osteoarthritis?

A. Atrial fibrillation is characterized by irregularly irregular rhythms with no distinct P-waves. Instead, it has a chaotic baseline with fibrillatory waves. The ventricular response can be irregular and variable. The description provided (regular P-waves in a sawtooth formation) does not match the typical appearance of atrial fibrillation, which lacks regular P-waves and has an irregular rhythm.
B. Atrial flutter is characterized by regular, sawtooth-shaped P-waves known as "F-waves" or "flutter waves." The classic pattern is referred to as "F-waves" with a "sawtooth" appearance, often seen in the inferior leads (II, III, aVF). The atrial rate is typically between 240 to 340 beats per minute, which fits the rate of 260 beats per minute in the description. The ventricular rate can be regular or irregular, depending on the degree of AV node conduction. A

C. Unstable angina is a clinical diagnosis of chest pain due to myocardial ischemia. It is not associated with specific ECG findings related to the P-wave morphology or rate. The ECG findings described do not correspond to unstable angina, which would typically present with ST-segment changes or other signs of myocardial ischemia rather than a specific P-wave pattern.
D. Premature atrial contractions (PACs) are early beats originating from the atria that interrupt the normal rhythm. They usually present as a single early beat with a different morphology of the P-wave compared to the sinus P-waves, but do not result in a regular sawtooth pattern or a sustained rhythm at high rates like the one described.

Myasthenia Gravis

Myasthenia Gravis (MG) is an autoimmune disorder characterized by weakness and rapid fatigue of voluntary muscles. Key features include fluctuating muscle weakness that typically worsens with activity and improves with rest, bilateral ptosis (drooping of the eyelids), and difficulty with swallowing and speaking. The fact that the client's facial muscle strength is better in the morning and worsens throughout the day is a hallmark of MG. The edrophonium (Tensilon) test is specifically used to diagnose MG by temporarily improving muscle strength.

Antibodies at the neuromuscular junction

Myasthenia Gravis is caused by the presence of autoantibodies that target acetylcholine receptors at the neuromuscular junction, leading to impaired communication between nerves and muscles. This is consistent with the described symptoms and the use of the edrophonium (Tensilon) test to diagnose the condition.