**9.5. Coronary angiography and left ventriculography**

The necessity to exclude an acute myocardial infarction in patients presenting with anginalike symptoms and typical ECG-changes predicates the use of coronary angiography. In TTS, the epicardial coronary arteries typically do not have any significant stenoses; however, there is possibility of bystander CAD considering the older age group of the presenting patients. A co-existing CAD has been reported in almost 10% of all TTS cases [50, 51]. The coronary stenosis in this scenario may or may not be hemodynamically significant; however, it is generally insufficient to explain the acute LV dysfunction and regional wall-motion abnormalities transpiring in the Takotsubo syndrome.

The exclusion of occlusive coronary artery disease, acute plaque rupture, thrombus formation and coronary dissection should be followed by a left ventriculography (if not contraindicated). This is necessary to confirm the pattern of LV wall-motion abnormality and diagnose, if any, mitral regurgitation. It also allows direct measurement of the pressure gradient across the LVOT [42], see **Figure 3**.

#### **9.6. Coronary computed tomography angiography**

The role of coronary computed tomography angiography (CCTA) is limited to cases where a delay in access to urgent invasive coronary angiography is expected. Information acquired throughout the cardiac cycle (spiral or helical acquisition mode) during the acute phase could demonstrate the typical pattern of systolic dysfunction [52]; however, this would come at the cost of greater radiation exposure. Retrospective evaluation of patients with typical history of TTS could also theoretically include CCTA to exclude significant coronary stenosis.

#### **9.7. Radionuclide imaging**

Single-photon emission tomography (SPECT) with 201Thallium or 99mTechnetium-labelled radiopharmaceuticals and 123I-metaIodobenzyl-guanidine (mIBG) has been used to demonstrate

**Figure 3.** Laevocardiography of TTS patient with typical apical ballooning triggered by emotional stress.

myocardial perfusion and sympathetic innervation. A reduced mIBG in the dysfunctional myocardial segments during the acute phase is consistent with disturbances in regional sympathetic neuronal activity [53, 54], and its use in diagnosing TTS has been suggested in combination with myocardial perfusion scintigraphy to exclude infarction.

18F-fluorodeoxyglucose (FDG) has been used to study myocardial glucose metabolism by positron emission tomography (PET); however, its current use has been relegated to scientific research [55].
