Assessment of myocardial perfusion, metabolism and sympathetic function benefits the diagnosis and follow-up of patients with Takotsubo cardiomyopathy

Objectives Takotsubo cardiomyopathy (TC) is a heart syndrome with an acute onset defined by chest symptoms, ST segment elevation on electrocardiograms. Several studies reported the utility of nuclear imaging including I-123-BMIPP, I-123-MIBG and perfusion scintigraphy. However, few data exist regarding the clinical impact of nuclear imaging on diagnosis and follow-up of TC.

Methods We examined 22 patients (aged 68±13) with TC. All patients were studied with resting BMIPP or MIBG in comparison to perfusion imaging. MIBG myocardial scintigraphy was performed 15min and 3 h after the injection. BMIPP were imaged after 20 min after the injection. Total defect score (TDS) was calculated.

Results Coronary angiography showed the absence of stenotic regions in the subjects. Abnormal BMIPP uptake of the myocardium was seen in patients with TC (86%), with complete or partial agreement with perfusion imaging. The degree of damage in BMIPP ranged from moderate to severe at subacute phase, but had almost normalized at chronic phase in patients with TC (TDS; 10±4 vs 1.4±1, p<0.01). Regional MIBG abnormality was observed (100%) in patients with TC and the abnormalities were observed exclusively in the apical region (91%). The discrepancies between apical MIBG decrease and perfusion suggested the stunned myocardium. Global MIBG uptake shown by the heart-to-mediastinum ratio was lower in patients with TC than that of age-matched control subjects (2.3±0.3 vs 2.6±0.2, p<0.05). The MIBG abnormality lasted at least one month after the onset of the disease (TDS; 12±4 in subacute phase vs 11±4 in chronic phase, NS).

Conclusions The serial changes in myocardial fatty acid metabolism and sympathetic nerve function could give us information on the severity of patients with TC. These results demonstrate that nuclear imaging can detect myocardial injury associated with TC and may benefit in monitoring clinical course or response to the treatment