The natural history of takotsubo syndrome: a two-year follow-up study with myocardial sympathetic and perfusion G-SPECT imaging

A Review of Nuclear Imaging in Takotsubo Cardiomyopathy

Takotsubo cardiomyopathy or Takotsubo Syndrome (TTS) is a reversible left ventricular dysfunction syndrome that is increasingly being recognized. Recent advances in nuclear imaging have allowed us to study TTS in greater detail. We searched the PubMed and Medline databases and identified 53 publications with 221 patients reporting nuclear imaging findings in TTS. The age of the patients ranged from 17 to 87 years and were predominantly women (88.2%). The TTS variant was apical (typical) in 170 (76.9%), mid-ventricular in 23 (10.4%), and basal (reverse TTS) in 2 (0.9%). Cardiac perfusion was assessed using ^99mTc sestamibi (MIBI) SPECT, ^99mTc tetrofosmin SPECT, ²⁰¹Tl SPECT, ⁸²Rb PET, ²⁰¹Tl SPECT, and ¹³N ammonia PET. Additional studies used were ¹²³I MIBG SPECT, ¹²³I BMIPP SPECT, ¹⁸F FDG PET, ⁶⁷Ga citrate, and ¹¹C hydroxy-ephedrine. A perfusion defect was seen in 69 (31.2%), and an inverse perfusion–metabolism mismatch (normal or near-normal perfusion with absent myocardial metabolic activity) was seen in 183 (82.8%) patients. Nuclear imaging has a significant role in evaluating, diagnosing, and prognosticating patients with TTS. As nuclear imaging technology evolves, we will surely gain more insights into this fascinating disorder.

Novel Imaging and Genetic Risk Markers in Takotsubo Syndrome

Takotsubo syndrome (TTS) is an increasingly recognized condition burdened by significant acute and long-term adverse events. The availability of novel techniques expanded the knowledge on TTS and allowed a more accurate risk-stratification, potentially guiding clinical management. The present review aims to summarize the recent advances in TTS prognostic evaluation with a specific focus on novel imaging and genetic markers. Parametric deformation analysis by speckle-tracking echocardiography, as well as tissue characterization by cardiac magnetic resonance imaging T1 and T2 mapping techniques, currently appear the most clinically valuable applications. Notwithstanding, computed tomography and nuclear imaging studies provided limited but promising data. A genetic predisposition to TTS has been hypothesized, though available evidence is still not sufficient. Although a genetic predisposition appears likely, further studies are needed to fully characterize the genetic background of TTS, in order to identify genetic markers that could assist in predicting disease recurrences and help in familial screening.

[Clinical Manifestation of Stressful Cardiomyopathy (Takotsubo Syndrome) and the Problem of Differential Diagnosis with Acute Myocardial Infarction]

The presented data show that tacotsubo syndrome (TS) is characterized by the absence of coronary artery obstruction, cardiac contractile dysfunction, apical ballooning, and heart failure, and in some patients, ST-segment elevation and prolongation of the QTc interval. Every tenth patient with TS develops ventricular arrhythmias. Most of TS patients have elevated markers of necrosis (troponin I, troponin Т, and creatine kinase МВ (CK-МВ), which are considerably lower than in patients with acute myocardial infarction (AMI) with ST-segment elevation. The level of N-terminal pro-B-type natriuretic peptide (NT-proBNP), in contrast, is considerably higher in patients with TS than with AMI. Differential diagnosis of TS and AMI should be based on a multifaceted approach using coronary angiography, echocardiography, analysis of ECG, magnetic resonance imaging, single-photon emission computed tomography, and measurement of troponins, CK-MB, and NT-proBNP.

Comparison of the first episode with the first recurrent episode of takotsubo syndrome in 128 patients from the world literature: Pathophysiologic connotations

BACKGROUND

The pathophysiology of takotsubo syndrome (TTS) and its recurrence (REC-TTS) is still elusive. Various ventriculographic "ballooning" patterns in response to a variety of triggers are observed in patients with REC-TTS. Although patients with and without REC-TTS have been previously compared, no comparison of patients' 1st TTS episode (1stTTS) with the 1st REC-TTS episode (1stREC-TTS) has been attempted.

METHODS

All patients with ≥1 REC-TTS episodes with patient-based data (45 variables) from the world literature, retrieved via PubMed, were meta-analyzed, and the patients' 1st REC-TTS and stREC-TTS were compared.

RESULTS

The time interval between the 1stTTS and 1stREC-TTS of the meta-analyzed 128 patients, 117 (91.4%) female, was 30.4 ± 36.1 months, with 47 (36.7%) patients having a neurological and/or psychiatric comorbidity(ies). Among 113 patients with paired 1stTTS and 1stREC-TTS data on the ventriculographic "ballooning" appearance, 101 (78.9%) had a different variant during the 1stTTS as compared with the 1stREC-TTS. Six patients (4.7%) died during hospitalization. Thirty patients (23.4%) were taking a β-blocker prior to their 1strTTS. Among 19 variables compared between the 1st TTS and 1st REC-TTS episodes, only mean age (by 2.5 years) and use of β-blockers were statistically significantly different. The precipitating triggers, and the in-hospital adverse events were similar in the 1st TTS and 1st REC-TTS episodes.

CONCLUSIONS

A comparison of the 1st TTS and 1st REC-TTS episodes of patients with REC-TTS, revealed large variation in the ventriculographic "ballooning" patterns, similarity in the TTS triggers, and no difference in the in-hospital adverse events. There was no protective effect for imparted by β-blockers in REC-TTS.

The role of multimodality imaging in takotsubo cardiomyopathy

Takotsubo cardiomyopathy (TC) is a syndrome of transient left ventricular (LV) dysfunction mimicking acute coronary syndrome. Although the mechanisms underlying the occurrence of TC are unknown, several imaging techniques contribute to its diagnosis. Here we review the current knowledge about TC, in particular, the pathophysiology and the role of imaging including nuclear cardiovascular medicine.

Cardioprotective properties of opioid receptor agonists in rats with stress-induced cardiac injury

The objectives of this study were to investigate the role of endogenous opioids in the mediation of stress-induced cardiomyopathy (SIC), and to evaluate which opioid receptors regulate heart resistance to immobilization stress. Wistar rats were subjected to 24 h immobilization stress. Stress-induced heart injury was assessed by 99mTc-pyrophosphate accumulation in the heart. The opioid receptor (OR) antagonists (naltrexone, NxMB - naltrexone methyl bromide, MR 2266, ICI 174.864) and agonists (DALDA, DAMGO, DSLET, U-50,488) were administered intraperitoneally prior to immobilization and 12 h after the start of stress. In addition, the selective micro OR agonists PL017 and DAMGO were administered intracerebroventricularly prior to stress. Finally pretreatment with guanethidine was used. Naltrexone did not alter the cardiac 99mTc-PP accumulation in stressed rats. NxMB aggravated stress-induced cardiomyopathy (P=0.005) (SIC). The selective micro OR agonist DALDA, which does not cross the blood-brain barrier, completely prevented (P=0.006) SIC. The micro OR agonist DAMGO exhibited weaker effect than DALDA. The selective delta ligand (DSLET) and kappa OR ligand (U-50,488) did not alter stress-induced 99mTc-pyrophosphate accumulation in the heart. Intracerebroventricular administration of the micro OR agonists aggravated SIC. Pretreatment with guanethidine abolished this effect (P=0.01). Guanethidine alone exhibited cardioprotective properties. A stimulation of central micro OR promotes an appearance of SIC. In contrast, stimulation of peripheral micro OR contributes to an increase in cardiac tolerance to stress.

Impact of gender on in-hospital outcomes in patients with Takotsubo syndrome: A nationwide analysis from 2006 to 2014

BACKGROUND

Takotsubo syndrome (TTS) is characterized by acute, transient systolic dysfunction of the left ventricle not attributed to coronary artery disease (CAD).

HYPOTHESIS

There are differences in hospital outcomes in patients admitted with TTS based on their gender.

METHODS

The National Inpatient Sample database was searched for patients admitted with a principal diagnosis of TTS from 2006 to 2014 using the ICD9-CM code 429.83. Using Pearson's χ² and Student's t test analyses, the P-value was calculated for differences among baseline characteristics of patients. Multivariate regression models were then created to adjust for potential confounders.

RESULTS

A total of 39 662 admissions with TTS were identified, 91.7% female and 8.3% male with mean age of 66.5 and 61.6 years, respectively. The incidence of TTS increased progressively from 2006 to 2014. Female patients were more likely to have hypertension, hypothyroidism, or depression. Males were more likely to use tobacco, or have known CAD. Males had almost 4-fold higher probability of in-hospital mortality compared to females (3.7% vs 1.1%; P<0.001). Certain complications including cardiogenic shock, ventricular fibrillation/tachycardia, and acute kidney injury were more common in males.

CONCLUSIONS

There are distinct gender differences in clinical characteristics of patients admitted with TTS. Although TTS is more common in females, it is associated with higher morbidity and mortality in males.

Roles of cardiac sympathetic neuroimaging in autonomic medicine

Sympathetic neuroimaging is based on the injection of compounds that either radiolabel sites of the cell membrane norepinephrine transporter (NET) or that are taken up into sympathetic nerves via the NET and radiolabel intra-neuronal catecholamine storage sites. Detection of the radioactivity is by planar or tomographic radionuclide imaging. The heart stands out among body organs in terms of the intensity of radiolabeling of sympathetic nerves, and virtually all of sympathetic neuroimaging focuses on the left ventricular myocardium. The most common cardiac sympathetic neuroimaging method worldwide is ¹²³I-metaiodobenzylguanidine (¹²³I-MIBG) scanning. ¹²³I-MIBG scanning is used routinely in Europe and East Asia in the diagnostic evaluation of neurogenic orthostatic hypotension (nOH), to distinguish Lewy body diseases (e.g., Parkinson disease with orthostatic hypotension (OH), pure autonomic failure) from non-Lewy body diseases (e.g., multiple system atrophy) and to distinguish dementia with Lewy bodies from Alzheimer's disease. In the USA, ¹²³I-MIBG scanning has been approved by the Food and Drug Administration for the evaluation of pheochromocytoma and some forms of heart failure-but not for the above-mentioned differential diagnoses. Positron emission tomographic methods based on imaging agents such as ¹⁸F-dopamine are categorized as research tools, despite more than a quarter century of clinical experience with these modalities. Considering that ¹²³I-MIBG scanning is available at most academic medical centers in the USA, cardiac sympathetic neuroimaging by this methodology merits consideration as an autonomic test, especially in patients with nOH.