What is a consequence of untreated heartworm disease in dogs?

Untreated heartworm disease leads to several physiological changes in the body, primarily affecting the cardiovascular and pulmonary systems. One of the most common consequences is decreased exercise tolerance. As heartworms mature and infest the pulmonary arteries, they cause inflammation and obstruction of blood flow. This can result in pulmonary hypertension and right-sided heart failure, both of which hinder the heart's ability to pump effectively. Consequently, dogs affected by heartworm disease experience shortness of breath, fatigue, and an overall decrease in stamina during physical activity. This reduced capacity to exercise can manifest as difficulty in performing routines that the dog previously handled with ease.

Conversely, options such as increased skin infections, improved blood flow, and enhanced lung function do not accurately reflect the effects of untreated heartworm disease. While an animal with a heartworm infestation may be susceptible to skin infections due to a compromised immune system or decreased health overall, this is not a direct consequence of heartworm disease itself. In addition, heartworm disease would not result in improved blood flow or enhanced lung function; rather, it does the opposite by creating blockages and impairments in the cardiac and respiratory systems.