Background: The clinical features of the tako-tsubo cardiomyopathy or transient left apical ballooning syndrome (LABS) are well described but the mechanisms remain unknown. Myocardial stunning is suggested. Whether the coronary microcirculation is involved is still unclear.

Objective: to assess prospectively the coronary microcirculation in LABS, at the acute phase and after functional recovery, using serial transthoracic Doppler coronary flow reserve (T-CFR).

Methods: eleven consecutive patients (all women, mean age 68 ± 10 years) who fulfilled the criteria for LABS (acute chest pain, ECG abnormalities, transient balloon-like left ventricular wall motion abnormalities at the apex of the ventricle, normal coronary angiography and a stressful event), underwent T-CFR in the distal part of the left anterior descending artery, using intravenous adenosine infusion (0.14 µg/kg/min over 2 min), in the acute phase (48 h after symptom onset) and 25 ± 3 days apart. CFR was calculated as the ratio of hyperemic to basal mean diastolic flow velocity. Wall motion score (WMS) was calculated using the 16-segment model, during the same echocardiographic examination (normal WMS = 16).

Results: T-CFR increased between the 2 examinations: from 2.2 ± 0.4 in the acute phase to 2.9 ± 0.3 (p < 0.01), while WMS decreased (from 31 ± 6 in the acute phase to 16.5 ± 0.8, delta WMS = -14 ± 6, p < 0.01). All patients exhibited an increase of CFR between the 2 exams (delta CFR = 0.73 ± 0.4, range from 0.3 to 1.6). There was a close correlation between delta CFR and delta WMS (r = -0.87, p < 0.01). No significant changes of the hemodynamic variables occurred between the 2 examinations.

Conclusion: Serial non-invasive CFR measurements performed in LABS show transient microcirculatory impairment during the acute phase of the syndrome. The wall motion improvement parallel to the dynamic improvement of the microcirculation suggests a role of coronary microcirculatory damage in the pathogenesis of acute and transient wall motion abnormalities in LABS.