Implications of Acute Left Ventricular Remodeling during Squatting Stress Echocardiography

BACKGROUND: We previously demonstrated that squatting induces left ventricular (LV) wall motion abnormalities (WMA) in areas subtended by stenotic coronary arteries. In addition, it was observed that some subjects developed acute changes in LV shape (acute left ventricular remodeling [ALVRM]) during squatting. OBJECTIVE: This study tested the hypothesis that patients with ALVRM during squatting echocardiography have higher incidences of severe coronary artery disease (CAD). METHODS: Echocardiography was performed in all standard views during standing and squatting. End-systolic frames in the apical four-chamber view were analyzed. RESULTS: The subjects were divided into three groups. Group 1 consisted of 12 subjects who developed squatting-induced ALVRM with apical and distal posterior septal akinesis, dilation of the apex and marked LV shape change at end-systole. Group 2 consisted of 20 subjects with distal posterior septal and apical akinesis without ALVRM, during squatting. Group 3 consisted of 64 subjects who developed WMA in areas other than the apex (n = 49), or normal wall motion (n = 15) during squatting. Coronary angiography in group 1 revealed that 6 subjects had left main coronary artery stenosis (LMCAS ≥ 50%), two had severe three vessel disease (≥ 90% stenosis), and one had 100% left anterior descending coronary artery occlusion. Severe CAD was defined for purpose of this study as the presence of LMCAS, or severe three vessel disease (≥ 90% stenosis). Six subjects in group 2 had LMCAS and none had severe three vessel disease (P < 0.05 vs. group 1 for LMCAS and/or three vessel disease). In group 3, eight had LMCAS and none had severe three vessel disease (P < 0.0001 vs. group 1). CONCLUSION: Patients with ALVRM have severe CAD. Therefore, patients who develop ALVRM during squatting require urgent evaluation for revascularization therapy.