What potential complications can arise from untreated atrial septal defects?

Untreated atrial septal defects (ASDs) can lead to significant complications, including pulmonary hypertension and right heart failure, primarily due to the increased blood flow to the right side of the heart and the lungs.

When an ASD is present, there is an abnormal opening between the left and right atria, allowing oxygen-rich blood to mix with oxygen-poor blood. This results in an overload of blood returning to the right atrium and subsequently the right ventricle. Over time, this increased blood flow can cause elevated pressure in the pulmonary arteries (pulmonary hypertension), as the lungs are receiving more blood than they can efficiently process. This condition strains the heart and can lead to right heart failure, where the right side of the heart struggles to pump blood effectively.

In terms of the other options, while complications such as stroke and arrhythmia are possible in certain cardiac conditions, they are less directly tied to untreated ASDs than pulmonary hypertension and right heart failure. A heart murmur and tachycardia can be observed during physical examination but are not complications; rather, they are clinical findings associated with ASD. Myocardial infarction and cardiomyopathy are more relevant to other conditions such as coronary artery disease or prolonged volume overload from