Background: Takotsubo cardiomyopathy (TC) mimics ST-elevation myocardial infarction without substantial angiographic stenosis. Coronary microvascular dysfunction has been proposed as a possible mechanism in TC. The aim of this study was to evaluate microvascular function in TC using real-time myocardial contrast echocardiography (MCE).
Methods: Real-time MCE was performed within 24 hours of coronary angiographic diagnosis of TC. Myocardial perfusion was evaluated through qualitative and quantitative myocardial contrast echocardiographic analyses comparing normal segments with segments with dysfunctional wall motion (WM).
Results: From January 2007 to January 2008, 11 patients received diagnoses of TC. Of these patients, 9 were prospectively enrolled (mean age, 70.9 +/- 17.5 years; 8 women). Qualitative and quantitative myocardial contrast echocardiographic analyses were feasible in 87% and 81% of segments. Overall, concordance between qualitative MCE and WM for normal versus abnormal analysis was observed in 71% of segments (kappa = 0.442, SE = 0.08). Significantly lower myocardial blood flow velocity (beta) and lower myocardial blood flow (Abeta) were detected in segments with dysfunctional WM compared with those with normal WM (beta = 0.55 +/- 0.39 vs 0.90 +/- 0.77, P = .009; Abeta = 5.31 +/- 3.92 vs 12.38 +/- 13.47, P = .002). In the discordant segments between qualitative MCE and WM, the quantitative perfusion parameters beta and Abeta were significantly lower in segments with dysfunctional WM compared with those with normal WM (beta = 0.22 +/- 0.20 vs 1.79 +/- 0.57, P = .01; Abeta = 1.90 +/- 1.1 vs 24.29 +/- 19.9, P = .02). Recovery of WM abnormalities was detected in all patients during follow-up echocardiography (mean, 60.3 +/- 66.0 days). No contrast-related side effects were reported. During mean follow-up of 5.9 +/- 4.6 months, there were no cardiac events, but 1 noncardiac death (from lung cancer) occurred.
Conclusion: TC is associated with abnormal myocardial perfusion detected with qualitative and quantitative MCE, indicative of microvascular dysfunction.