Introduction: Dyskinesis is diagnosed by outward systolic bulging, but a similar inferior wall (IW) motion is sometimes observed in patients without infarction. Such diastolic flattening of the IW is followed by systolic rounding and outward bulging, consistent with extrinsic diastolic compression that is overcome by systolic contraction.
Hypothesis: Pseudodyskinesis (PD) (paradoxical IW motion) is associated with preserved systolic wall thickening and does not reflect ischemic dysfunction.
Methods: We compared 100 consecutive patients having a pattern of PD on transthoracic echocardiography with control groups of 50 patients with documented inferior myocardial infarction and 50 healthy individuals. Percent systolic thickening of the inferior, anterior, septal, and lateral left ventricular (LV) walls was measured in a midventricular short-axis view, and LV cross-sectional shape was evaluated by the ratio of two perpendicular diameters. Diaphragmatic position was evaluated on chest radiograph.
Results: Systolic IW thickening was not significantly different in PD from that of normal (58.2 +/- 6.2% vs 53.0 +/- 4.6%) and of non-IW in the same patients (50.4 +/- 6.8%). The LV was circular (diameter ratio = 1.0) in systole and diastole in healthy individuals; in PD, it was noncircular in diastole consistent with IW compression (P < .01), and circular in systole; in inferior myocardial infarction, it was circular in diastole and noncircular in systole (P < .01) consistent with decreased IW contraction. The left hemidiaphragm was more elevated in PD (78% vs 8.5%, P < .01).
Conclusions: In PD, the IW thickens normally to produce a circular LV cavity in systole. This motion, consistent with extrinsic compression, is important to distinguish from inferior myocardial infarction.