Stunned myocardium in transient left ventricular apical ballooning: A serial study of dual I-123 BMIPP and Tl-201 SPECT

Background. This study was designed to assess the influence of coronary endothelial function and the serial changes of dual myocardial single photon emission computed tomography (SPECT) imaging in transient left ventricular (LV) apical ballooning. Methods and Results. We evaluated 35 consecutive patients (8 men and 27 women; mean age, 71 ±13 years) with transient LV apical ballooning. All patients underwent coronary angiography with acetylcholine provocation 1 month after onset. Iodine 123 β-methyl-p-iodophenyl-pentadecanoic acid (BMIPP) and thallium 201 dual myocardial SPECT was serially performed on day 1 of admission and 1 month and 6 months later. In 8 of 35 patients (23%), epicardial coronary spasm was induced by acetylcholine infusion. At the peak acetylcholine dose (100 μg), diffuse coronary vasoconstriction developed in 19 of 35 patients (54%). Of 19 patients, 13 had diffuse coronary vasoconstriction with chest pain and ST-segment depression. The total defect score of I-123 BMIPP and Tl-201 SPECT showed marked perfusion-fatty acid metabolic mismatches (13.7±3.6 vs 8.7±2.3, P<.001) at the LV apex during the acute phase but few mismatched areas (2.1±1.1 vs 1.5±1.4, P = not significant) at 6 months. Conclusions. Transient LV apical ballooning might be caused by stress-induced coronary epicardial spasm or endothelial dysfunction, resulting in myocardial stunning.