Abstract 1072: Myocardial and Microvascular Stunning in Apical Ballooning Syndrome

Abstract

Apical Ballooning Syndrome (ABS) is characterized by chest pain, ST segment elevation at ECG, normal coronary arteries and transient left ventricular (LV) apical a-dyskinesia that typically recovers within a few weeks. Limited and conflicting data about microvascular flow pattern in ABS exist so far. Eight consecutive patients (all women, 72±14 years) presenting with ABS were evaluated by Myocardial Contrast Echocardiography (MCE) at rest, during adenosine test and at 1 month follow-up. Myocardial dysfunction was assessed by Wall Motion Score Index (WMSI) and endocardial length of contractile dysfunction defect (CDD), while myocardial perfusion by Contrast Score Index (CSI) and endocardial length of perfusion defect (PD). MCE study was performed during the infusion of contrast medium (Sonovue, Bracco) at rest and at peak of 90 seconds-infusion of adenosine (140 μg/Kg/min) to elicit coronary microvascular response. LV perfusion defect was present in apical dysfunctional myocardium in all patients. Compared to resting condition, during adenosine WMSI decreased from 1.90±0.29 to 1.72±0.32 (p<.01) and CDD from 40.3±15.5% to 33.2±15.3% of LV endocardial length (p<.001). Similarly, during adenosine test, CSI decreased from 1.55±0.21 to 1.36±0.16, (p<.01) and PD from 23.8±8.6% to 18.6±6.5% of LV endocardial length (p<.05). At follow-up, both myocardial and microvascular dysfunction reverted to normal. Our early results indicate that ABS is characterized by a condition of regional myocardial and microvascular dysfunction partially reversible during adenosine infusion and entirely reversible at 1-month follow-up. These observations suggest that myocardial stunning associated with microvascular stunning could represent a common pathophysiologic pattern in ABS.