In today's VETgirl online veterinary CE podcast, we review the features and outcome in dogs that were treated with sildenafil -; yes, Viagra -; for the treatment of pulmonary hypertension. Pulmonary hypertension (PH) is a condition of elevated pulmonary artery pressure that is currently divided into five distinct groups in humans based on etiology by the World Health Organization (WHO). Similar divisions by the veterinary community (American College of Veterinary Internal Medicine Consensus Statement) are currently in process. The current WHO divisions include: