Abstract
The heart and lungs, the primary organs of the circulatory and respiratory systems, respectively, are housed within the thorax, also known as the thoracic cavity. This chapter provides an overview of common congenital heart diseases in dogs and their effects on cardiac function, particularly with respect to volume and pressure overload. An assessment of the cardiovascular system begins with observation of the patient. Acquired heart disease is not present at birth but develops over time, most commonly in middle-aged to older dogs, and takes one of two forms: acquired valvular diseases; acquired disorders of the heart muscle (cardiomyopathy). Airway sounds occur when air flows through space and creates vibrations. Both the upper and lower airways should be auscultated in every patient to appreciate airway sounds. Both percussion and auscultation are valuable tools for detecting thoracic cavity diseases.