Pulsus paradoxus refers to decrease in the systolic pressure during inspiration. It occurs due to altered mechanical forces on the heart chambers secondary to many condition. Most common causes of pulsus paradoxus are: - cardiac tamponade - constrictive pericarditis - asthma - right ventricular myocardial infarction - restrictive cardiomyopathy - tension pneumothorax - bilateral pleural effusion - pulmonary embolism - iatrogenic injury - pectus excavatum Reference: https://www.ncbi.nlm.nih.gov/books/NBK482292/ Image via: https://www.verywellhealth.com/pulsus-paradoxus-4587588