Which sinus arrhythmia can occur after an inferior wall myocardial infarction?

Sinus bradycardia is indeed the correct answer in the context of an inferior wall myocardial infarction. This type of arrhythmia is characterized by a slower than normal heart rate, typically below 60 beats per minute.

In cases of inferior wall myocardial infarction, there can be damage to the areas of the heart that influence heart rate, particularly because the right coronary artery often supplies the inferior wall and can impact the vagal tone and conduction pathways. The increase in vagal tone or damage to the conduction system may lead to a decrease in the heart rate, resulting in sinus bradycardia.

This is differential from other types of arrhythmias listed in the choices, like sinus tachycardia which is an increased heart rate, or sinus rhythm which indicates a normal heart rate, typically around 60-100 beats per minute. Sinus arrest, on the other hand, refers to a pause in the sinus node activity that may not typically follow an inferior wall infarct. Thus, understanding the relationship between the inferior wall myocardial infarction and its potential effects on heart rate regulation emphasizes why sinus bradycardia is the correct and relevant arrhythmia in this context.