In addition, typically, patients with constrictive pericarditis
have respiratory variation in mitral E velocity: a
25% increase with expiration.149 However, up to 50% of
patients with constrictive pericarditis demonstrate ,25%
respiratory variation in mitral E velocity. On the other
hand, patients in respiratory distress, such as those with
asthma, sleep apnea, chronic obstructive lung disease, and
obesity, may show exaggerated respiratory variation in
mitral E velocity due to increased swings in intrathoracic
pressure.