Paradoxical septal motion is defined as movement of the interventricular septum away from the left ventricular free wall during systole which is the opposite of its normal movement which is inward toward the left ventricle / or the left ventricular free wall during systole.

• Arrhythmogenic RV dysplasia
• Atrial septal defect
• Constrictive pericarditis
• Following heart surgery. There may be altered LV function and lack of restraint on the pericardium if it is opened.
• Hibernation of the septal myocardium
• Myocardial infarction of the septal myocardium
• Ischemic heart disease involving the septal myocardium
• Left bundle branch block in 14/17 cases ^[1], particularly if the QRS is > 150 ms or if there is septal fibrosis
• Mitral stenosis
• Pericardial effusion (large)
• Following a pericardial incision
• Pulmonary embolism
• Pulmonary hypertension
• Repaired Tetralogy of Fallot
• Right ventricular hypertrophy
• Right ventricular pacing, particularly from the right ventricular outflow tract due to contraction of the RV before the LV
• Right ventricular tumor
• Right ventricular volume overload
• Stunning of the septal myocardium
• Wolff-Parkinson-White type B syndrome

Certain surgical procedures are independently associated with a higher risk of PSM:^[2]

• Aortic valve surgery (p=0.02)
• Mitral valve surgery (p<0.001)
• Longer cardiopulmonary bypass time (p < 0.001)

• Coronary artery bypass grafting (CABG) than non-CABG surgery (p = 0.003)
• Off-pump coronary artery bypass (OPCAB)

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