Which of the following is NOT a pathologic change that can lead to CHF?

Reduced cardiac output due to dehydration is not considered a pathologic change that leads to congestive heart failure (CHF). Instead, it is often a temporary condition that can result from various situational factors such as fluid loss from vomiting, diarrhea, or blood loss. While reduced cardiac output can certainly strain the heart, it doesn't fall within the chronic structural or functional changes associated with CHF.

In contrast, changes in myocardial contractility (such as decreased contractile function seen in conditions like myocardial infarction or cardiomyopathy) directly impact how effectively the heart can pump blood, leading to heart failure. Increased preload or afterload of the ventricle refers to situations where the heart is subjected to increased volume or resistance, respectively. Both conditions can exacerbate heart failure by making the heart work harder than normal. Structural integrity of the valves plays a crucial role in maintaining normal forward blood flow; dysfunctional valves due to regurgitation or stenosis can significantly hinder cardiac function and lead to heart failure. All of these factors are directly linked to the pathophysiology of CHF.