We compared Takotsubo cardiomyopathy (transient left ventricular apical ballooning) with acute myocardial infarction (AMI) using two-dimensional echocardiography, 99mTc-tetrofosmin, 99mTc-PYP, 123I-BMIPP and 123I-MIBG myocardial SPECT.
Methods: We examined 7 patients with Takotsubo cardiomyopathy and 7 with AMI at the time of emergency admission (acute phase), and 2-14 days (subacute phase), one month (chronic phase), and 3 months (chronic II phase) after the attack. The left ventricle was divided into nine regions on echocardiograms and SPECT images, and the degree of abnormalities in each region was scored according to five grades from normal (0) to severely abnormal (4).
Results: Coronary angiography showed the absence of stenotic regions in patients with Takotsubo cardiomyopathy, and severely stenotic and/or occlusive lesions in patients with AMI. The total ST segment elevation on electrocardiograms (mm) was 7.8 +/- 3.7 in those with Takotsubo cardiomyopathy, and 7.3 +/- 3.9 in patients with AMI. Abnormal wall motion scores on echocardiograms were 14.2 +/- 4.6, 4.7 +/- 4.0, 1.7 +/- 2.0 and 0.5 +/- 0.4 during the acute, subacute, chronic and chronic II phases, respectively, in patients with Takotsubo cardiomyopathy, and 14.0 +/- 4.3, 11.4 +/- 3.9, 8.8 +/- 3.6 and 5.2 +/- 4.8 in those with AMI. Abnormal myocardial perfusion scores on 99mTc-tetrofosmin images were 11.8 +/- 3.5, 3.2 +/- 3.0, 0.5 +/- 1.2 and 0.2 +/- 0.4 during the acute, subacute, chronic and chronic II phases, in patients with Takotsubo cardiomyopathy, and 16.2 +/- 4.3, 13.9 +/- 4.6, 7.9 +/- 4.6 and 5.0 +/- 4.5, respectively, in those with AMI. Abnormal myocardial fatty acid scores on 123I-BMIPP images were 12.6 +/- 3.7, 6.8 +/- 3.2 and 0.4 +/- 0.6 during the subacute, chronic and chronic II phases, respectively, in patients with Takotsubo cardiomyopathy, and 16.5 +/- 5.1, 14.7 +/- 4.8 and 7.5 +/- 4.5 in those with AMI. Abnormal myocardial sympathetic nerve function scores on 123I-MIBG images were 14.8 +/- 4.0, 8.8 +/- 4.0 and 0.4 +/- 0.6 during the subacute, chronic, chronic II phases, respectively, in patients with Takotsubo cardiomyopathy, and 18.6 +/- 6.5, 16.8 +/- 6.8 and 12.9 +/- 5.2 in those with AMI. Myocardial 99mTc-PYP uptake was abnormal not only in patients with AMI but also in those with Takotsubo cardiomyopathy during the acute phase.
Conclusions: Takotsubo cardiomyopathy might represent a stunned myocardium caused by a disturbance of the coronary microcirculation.