Prognostic value of myocardial flow reserve obtained by 82-rubidium positron emission tomography in long-term follow-up after heart transplantation.

BACKGROUND: Cardiac allograft vasculopathy (CAV) is a leading cause of death following heart transplantation (HTx) and non-invasive prognostic methods in long-term CAV surveillance are needed. We evaluated the prognostic value of myocardial flow reserve (MFR) obtained by 82-rubidium (82Rb) positron emission tomography (PET). METHODS: Recipients undergoing dynamic rest-stress 82Rb PET between April 2013 and June 2017 were retrospectively evaluated in a single-center study. Evaluation by PET included quantitative myocardial blood flow and semiquantitative myocardial perfusion imaging. Patients were grouped by MFR (MFR ≤ 2.0 vs MFR > 2.0) and the primary outcome was all-cause mortality. RESULTS: A total of 50 patients (68% men, median age 57 [IQR: 43 to 68]) were included. Median time from HTx to PET was 10.0 (6.7 to 16.0) years. In 58% of patients CAV was documented prior to PET. During a median follow-up of 3.6 (2.3 to 4.3) years 12 events occurred. Survival probability by Kaplan-Meier method was significantly higher in the high-MFR group (log-rank P = .02). Revascularization (n = 1), new CAV diagnosis (n = 1), and graft failure (n = 4) were more frequent in low-MFR patients. No retransplantation occurred. CONCLUSIONS: Myocardial flow reserve appears to offer prognostic value in selected long-term HTx recipients and holds promise as a non-invasive method for CAV surveillance possibly guiding management strategy.

Biomarkers in patients with Takotsubo cardiomyopathy compared to patients with acute anterior ST-elevation myocardial infarction.

Background: Takotsubo cardiomyopathy (TTC) is a syndrome of acute non-coronary heart failure with similar symptoms and electrocardiograms to acute anterior ST-elevation myocardial infarction (STEMI). Little is known about the pathophysiology of TTC. We assessed admission plasma concentrations of biomarkers reflecting neuroendocrine response (copeptin, mid-regional-pro-adrenomedullin, pro-atrial-natriuretic-peptide, soluble thrombomodulin (sTM), syndecan-1) and inflammation (suppression-of-tumorigenicity 2 (ST2), high-sensitive C-reactive-protein) in TTC patients and compared to patients with acute anterior STEMI.Materials and methods: Twenty TTC patients were matched with 40 STEMI patients by age, gender and left ventricular ejection fraction. Blood was sampled upon hospital admission immediately before acute coronary angiography.Results: The groups had similar comorbidities. TTC patients had higher plasma concentrations of sTM: 7.94 (5.89;9.61) vs. 6.42 (5.50;7.82)ng/ml, p = 0.04 and ST2 (53 (32;157) vs. 45 (31;55)ng/ml, p = 0.008) and higher heart rate: 101 ([Formula: see text]33) vs. 76([Formula: see text]14)bpm, p = 0.0001, but lower concentrations of copeptin (10.4 (7.6;39) vs. 92.3 (13;197)pmol/l, p < 0.05) and troponin T (348 (98;759) vs. 1190 (261;4105)ng/l, p = 0.04).Conclusion: TTC patients had higher plasma concentrations of sTM and ST2, higher heart rate and lower copeptin and troponin T concentrations compared to acute anterior STEMI patients. This study contributes to the hypothesis that TTC patients have endothelial cell damage and are hemodynamically more stable than patients with acute anterior STEMI on admission.

Subacute cardiac rubidium-82 positron emission tomography (82Rb-PET) to assess myocardial area at risk, final infarct size, and myocardial salvage after STEMI.

BACKGROUND: Determining infarct size and myocardial salvage in patients with ST-segment elevation myocardial infarction (STEMI) is important when assessing the efficacy of new reperfusion strategies. We investigated whether rest 82Rb-PET myocardial perfusion imaging can estimate area at risk, final infarct size, and myocardial salvage index when compared to cardiac SPECT and magnetic resonance (CMR). METHODS: Twelve STEMI patients were injected with 99mTc-Sestamibi intravenously immediate prior to reperfusion. SPECT, 82Rb-PET, and CMR imaging were performed post-reperfusion and at a 3-month follow-up. An automated algorithm determined area at risk, final infarct size, and hence myocardial salvage index. RESULTS: SPECT, CMR, and PET were performed 2.2 ± 0.5, 34 ± 8.5, and 32 ± 24.4 h after reperfusion, respectively. Mean (± SD) area at risk were 35.2 ± 16.6%, 34.7 ± 11.3%, and 28.1 ± 16.1% of the left ventricle (LV) in SPECT, CMR, and PET, respectively, P = 0.04 for difference. Mean final infarct size estimates were 12.3 ± 15.4%, 13.7 ± 10.4%, and 11.9 ± 14.6% of the LV in SPECT, CMR, and PET imaging, respectively, P = .72. Myocardial salvage indices were 0.64 ± 0.33 (SPECT), 0.65 ± 0.20 (CMR), and 0.63 ± 0.28 (PET), (P = .78). CONCLUSIONS: 82Rb-PET underestimates area at risk in patients with STEMI when compared to SPECT and CMR. However, our findings suggest that PET imaging seems feasible when assessing the clinical important parameters of final infarct size and myocardial salvage index, although with great variability, in a selected STEMI population with large infarcts. These findings should be confirmed in a larger population.

Coronary microvascular function and myocardial fibrosis in women with angina pectoris and no obstructive coronary artery disease: the iPOWER study.

BACKGROUND: Even in absence of obstructive coronary artery disease women with angina pectoris have a poor prognosis possibly due to coronary microvascular disease. Coronary microvascular disease can be assessed by transthoracic Doppler echocardiography measuring coronary flow velocity reserve (CFVR) and by positron emission tomography measuring myocardial blood flow reserve (MBFR). Diffuse myocardial fibrosis can be assessed by cardiovascular magnetic resonance (CMR) T1 mapping. We hypothesized that coronary microvascular disease is associated with diffuse myocardial fibrosis. METHODS: Women with angina, a clinically indicated coronary angiogram with <50 % stenosis and no diabetes were included. CFVR was measured using dipyridamole (0.84 mg/kg) and MBFR using adenosine (0.84 mg/kg). Focal fibrosis was assessed by 1.5 T CMR late gadolinium enhancement (0.1 mmol/kg) and diffuse myocardial fibrosis by T1 mapping using a modified Look-Locker pulse sequence measuring T1 and extracellular volume fraction (ECV). RESULTS: CFVR and CMR were performed in 64 women, mean (SD) age 62.5 (8.3) years. MBFR was performed in a subgroup of 54 (84 %) of these women. Mean native T1 was 1023 (86) and ECV (%) was 33.7 (3.5); none had focal fibrosis. Median (IQR) CFVR was 2.3 (1.9; 2.7), 23 (36 %) had CFVR < 2 indicating coronary microvascular disease, and median MBFR was 2.7 (2.2; 3.0) and 19 (35 %) had a MBFR value below 2.5. No significant correlations were found between CFVR and ECV or native T1 (R 2 = 0.02; p = 0.27 and R 2 = 0.004; p = 0.61, respectively). There were also no correlations between MBFR and ECV or native T1 (R 2 = 0.1; p = 0.13 and R 2 = 0.004, p = 0.64, respectively). CFVR and MBFR were correlated to hypertension and heart rate. CONCLUSION: In women with angina and no obstructive coronary artery disease we found no association between measures of coronary microvascular disease and myocardial fibrosis, suggesting that myocardial ischemia induced by coronary microvascular disease does not elicit myocardial fibrosis in this population. The examined parameters seem to provide independent information about myocardial and coronary disease.

Myocardial perfusion of infarcted and normal myocardium in propofol-anesthetized minipigs using (82)Rubidium PET.

Cardiac Rubidium-82 ((82)Rb) positron-emission-tomography (PET) is a good method for quantification of myocardial blood flow in man. Quantification of myocardial blood flow in animals to evaluate new treatment strategies or to understand underlying disease is also of great interest but raises some challenges. Animals, which have been anesthetized during PET acquisition, might react differently to used stress medications, and therefore difficulties might exist while evaluating the resulting PET images using standard software packages from commercial vendors optimized for human hearts. Furthermore propofol, used for anesthesia, can influence myocardial perfusion and coronary flow reserve due to its vasorelaxant effect, and interactions might exist between propofol and used stress agents, potentially affecting the result of the examination. We present cardiac (82)Rb-PET studies performed in propofol-anesthetized minipigs with normal and infarcted myocardium stressed with both adenosine and dipyridamole. Despite the mentioned challenges, we were able to trace the small minipig heart with software designed for human cardiac PET and to achieve blood flow measurements comparable with results in humans with both adenosine and dipyridamole. We found dipyridamole to be a superior stress agent for this experimental setup. Finally, we were able to clearly identify the myocardial perfusion defect after an induced myocardial infarction.

Neuroticism, depression and anxiety in takotsubo cardiomyopathy.

BACKGROUND: Takotsubo cardiomypathy (TTC) causes acute reversible heart failure. Prior studies have indicated that the syndrome is associated with traits such as social inhibition, chronic psychological stress, and anxio-depressive disorders. The objective of this study was to further characterize key psychological/psychopathological traits of patients with TTC. METHODS: A survey of three groups was conducted: I) Female post-recovery TTC patients admitted between October 1(st) 2009 and December 10(th) 2014, II) Age, gender and geographically matched ST-elevation myocardial infarction (STEMI) patients, and III) Age, gender and geographically matched individuals from the background population. The following questionnaires were used in the survey: the WHO-5 Well-Being Index, Eysenck's Neuroticism Scale, the Major Depression Inventory, and the anxiety subscale of Symptoms Checklist (SCL-90). RESULTS: In total, 173 of 230 invitees (75 %) participated in the study. In comparison to the background controls, TTC patients reported significantly less well-being, more neuroticism, more depression, and more anxiety. The levels of well-being, depression and neuroticism were comparable between TTC and STEMI patients, but the level of anxiety was higher in the TTC patients. There was a negative correlation between the time since TTC admission and the total scores on the psychopathology rating scales. CONCLUSIONS: Patients with TTC reported significantly higher anxiety levels compared to both STEMI patients and background controls. However, unlike the STEMI patients, the TTC patients appeared to improve psychologically during the post-recovery phase. This may be a consolation for TTC patients in acute psychological distress.

Coronary flow velocity reserve by echocardiography: feasibility, reproducibility and agreement with PET in overweight and obese patients with stable and revascularized coronary artery disease.

BACKGROUND: Coronary flow velocity reserve (CFVR) measured by transthoracic Doppler echocardiography of the LAD is used to assess microvascular function but validation studies in clinical settings are lacking. We aimed to assess feasibility, reproducibility and agreement with myocardial flow reserve (MFR) measured by PET in overweight and obese patients. METHODS: Participants with revascularized coronary artery disease were examined by CFVR. Subgroups were examined by repeated CFVR (reproducibility) or Rubidium-82-PET (agreement). To account for time variation, results were computed for scans performed within a week (1-week) and for all scans regardless of time gap (total) and to account for scar tissue for patients with and without previous myocardial infarction (MI). RESULTS: Eighty-six patients with median BMI 30.9 (IQR 29.4-32.9) kg × m(-2) and CFVR 2.29 (1.90-2.63) were included. CFVR was feasible in 83 (97 %) using a contrast agent in 14 %. For reproducibility overall (n = 21) limits of agreement (LOA) were (-0.75;0.71), within-subjects coefficient of variation (CV) 11 %, and reliability 0.84. For reproducibility within 1-week (n = 13) LOA were (-0.33;0.25), within-subjects CV 5 %, and reliability 0.97. Agreement with MFR of the LAD territory (n = 35) was without significant bias and overall LOA were (-1.40;1.46). Agreement was best for examinations performed within 1-week of participants without MI of the LAD-territory (n = 12); LOA = (-0.68;0.88). CONCLUSIONS: CFVR was highly feasible with a good reproducibility on par with other contemporary measures applied in cardiology. Agreement with MFR was acceptable, though discrepancy related to prior MI has to be considered. CFVR of LAD is a valid tool in overweight and obese patients.

Takotsubo syndrome: State-of-the-art review by an expert panel - Part 1.

Takotsubo syndrome (TTS) is an acute cardiac condition independent of epicardial coronary obstruction that mimics acute coronary syndrome and is characterized by acute heart failure with reversible ventricular motion abnormalities. This consensus paper is the result of a multinational effort aiming to summarize the current state of the art on TTS. Experts in the field provide a thorough and detailed review of this syndrome. Several novel and unique sections are emphasized in this document, including the current state of the art on genetics of takotsubo syndrome, microRNAs (miRs), racial differences, role of cardiac spectroscopy and intracoronary imaging, as well as mechanical circulatory support. In part 1 of this two-part manuscript, we discuss how TTS came to be known, several patterns and forms it can take in patients, epidemiology and pathophysiology of the syndrome, and clinical presentation.

Takotsubo syndrome: State-of-the-art review by an expert panel - Part 2.

In part 2 of this two-part manuscript on takotsubo syndrome (TTS), we discuss typical biomarkers (particularly excess catecholamines and what kinds of electrocardiographic information operators should look for) and numerous complications the syndrome can cause. This consensus paper is the result of a multinational effort aiming to summarize the current state of the art on TTS. Several novel and unique sections are emphasized in this document, including the current state of the art on genetics of takotsubo syndrome, microRNAs (miRs), racial differences, role of cardiac spectroscopy and intracoronary imaging, as well as mechanical circulatory support. New structured algorithms are also proposed to aid clinicians in the decision-making process as well as future directions for research given the current lack of evidence-based medical approaches.

Transthoracic Doppler echocardiography compared with positron emission tomography for assessment of coronary microvascular dysfunction: The iPOWER study.

BACKGROUND: Coronary microvascular function can be assessed by transthoracic Doppler echocardiography as a coronary flow velocity reserve (TTDE CFVR) and by positron emission tomography as a myocardial blood flow reserve (PET MBFR). PET MBFR is regarded the noninvasive reference standard for measuring coronary microvascular function but has limited availability. We compared TTDE CFVR with PET MBFR in women with angina pectoris and no obstructive coronary artery disease and assessed repeatability of TTDE CFVR. METHODS: From a cohort of women with angina and no obstructive coronary artery stenosis at invasive coronary angiography, TTDE CFVR by dipyridamole induced stress and MBFR by rubidium-82 PET with adenosine was successfully measured in 107 subjects. Repeatability of TTDE CFVR was assessed in 10 symptomatic women and in 10 healthy individuals. RESULTS: MBFR was systematically higher than CFVR. Median MBFR (interquartile range, IQR) was 2.68 (2.29-3.10) and CFVR (IQR) was 2.31 (1.89-2.72). Pearson's correlation coefficient was 0.36 (p<0.01). Limits of agreement (2·standard deviation) assessed by the Bland-Altman (confidence interval, CI) method was 1.49 (1.29;1.69) and unaffected by time-interval between examinations. Results were similar when adjusting for rate pressure product or focusing on perfusion of the left anterior descending artery region. Limits of agreement (CI) for repeated CFVR in 10 healthy individuals and in 10 women with angina was 0.44 (0.21;0.68) and 0.48 (0.22; 0.74), respectively. CONCLUSION: CFVR had a good repeatability, but the agreement between CFVR and MBFR was modest. Divergence could be due to methodology differences; TTDE estimates flow velocities whereas PET estimates myocardial blood flow.

[Takotsubo cardiomyopathy is an acute cardiac syndrome induced by stress].

Takotsubo cardiomyopathy (TTC) is an acute cardiac syndrome, characterized by transient left ventricular dysfunction often following a stressful event in post-menopausal women. Symptoms are indistinguishable from myocardial infarction. However, TTC patients do not have a culprit lesion on acute angiography, and regional akinesia is not limited to a single vascular territory. As opposed to other cardiomyopathies TTC is completely reversible, albeit with a 5% mortality rate as well as a 10% re-occurrence rate. This article summarizes the current knowledge about aetiology, diagnostics and treatment.

Multimodality Cardiac Imaging for the Assessment of Left Atrial Function and the Association With Atrial Arrhythmias.

Several cardiac imaging modalities are able to visualize the left atrium (LA) and, therefore, allow for quantification of both structural and functional properties of this cardiac chamber. In echocardiography, only the maximal LA volume is included in the assessment of diastolic function at the current moment. Numerous studies, however, have shown that functional measures may be superior to the maximal LA volume in several aspects and to possess clinical value even in the absence of structural abnormalities. Such functional measures could prove particularly useful in the setting of predicting atrial fibrillation, which will be a point of focus in this review. Pivotal cardiac magnetic resonance imaging studies have revealed high correlation between LA fibrosis and risk of atrial fibrillation recurrence after catheter ablation, and subsequent multimodality imaging studies have uncovered an inverse relationship between LA reservoir function and degree of LA fibrosis. This has sparked an increased interest into the application of advanced imaging modalities, including both speckle tracking echocardiography and tissue tracking by cardiac magnetic resonance imaging. Even though increasing evidence has supported the use of functional measures and proven its superiority to the maximal LA volume, they have still not been adopted in clinical guidelines. The reason for this discrepancy may rely on the fact that there is little to no agreement on how to technically perform deformation analysis of the LA. Such technical considerations, limitations, and alternate imaging prospects will be addressed in this review.

(123)I-MIBG Scintigraphy in the Subacute State of Takotsubo Cardiomyopathy.

OBJECTIVES: The study sought to investigate adrenergic activity in patients with takotsubo cardiomyopathy (TTC). BACKGROUND: TTC is a specific type of reversible heart failure possibly caused by excessive catecholamine stimulation of the myocardium. Scintigraphic iodine-123-meta-iodobenzylguanidine (mIBG) imaging of the heart and measurement of plasma catecholamines can be used to assess adrenergic activity in vivo. The authors hypothesized that sympathetic nerve activity is increased in the subacute state of TTC, and this study used cardiac mIBG imaging and plasma levels of norepinephrine and epinephrine as markers to assess this hypothesis. METHODS: In this study, 32 patients with TTC and 20 controls were examined at admission and again on follow-up with echocardiography, mIBG scintigraphy, and plasma catecholamine measurements. RESULTS: Ejection fraction (EF) was initially 36 ± 9% but increased to >60% (p = 0.0004) in all patients with TTC. In the control subjects EF was initially higher (51 ± 11%; p = 0.0004) than in the patients with TTC. However, EF of the patients with TTC exceeded that of the control subjects on follow-up (56 ± 8%; p = 0.0007). The mIBG imaging showed a lower late (4-h) heart-to-mediastinum ratio (H/Mlate) (2.00 ± 0.38) and a higher washout rate (WR) (45 ± 12%) in the subacute state of TTC, both when compared with follow-up (H/Mlate: 2.42 ± 0.45; p = 0.0004; WR: 33 ± 14%; p = 0.0004) and when compared with the control group in the subacute state (H/Mlate: 2.34 ± 0.60, p = 0.035; WR: 33 ± 19%, p = 0.026). On follow-up, no differences in mIBG parameters were observed between the TTC and control groups (H/Mlate: 2.41 ± 0.51, p = 0.93; WR: 30 ± 13%, p = 0.48) group. In the TTC group, plasma epinephrine levels were elevated in the subacute state (Log2[epinephrine]: 6.13 ± 1.04 pg/ml), both when compared with follow-up (5.25 ± 0.62 pg/ml; p = 0.0004) and when compared with the control group in the subacute state (5.46 ± 0.69 pg/ml; p = 0.044), and these levels remained elevated in the TTC group on follow-up compared with the control group (4.56 ± 0.95 pg/ml; p = 0.014). No significant differences in plasma norepinephrine levels were observed. CONCLUSIONS: The present study supports a possible role of adrenergic hyperactivity in TTC.

Basal hyperaemia is the primary abnormality of perfusion in Takotsubo cardiomyopathy: a quantitative cardiac perfusion positron emission tomography study.

AIMS: Takotsubo cardiomyopathy (TTC) is characterized by acute completely reversible regional left ventricle (LV) akinesia and decreased tracer uptake in the akinetic region on semi-quantitative perfusion imaging. The latter may be due to normoperfusion of the akinetic mid/apical area and basal hyperperfusion. Our aim was to examine abnormalities of perfusion in TTC, and we hypothesized that basal hyperperfusion is the primary perfusion abnormality in the acute state. METHOD AND RESULTS: Twenty-five patients were diagnosed with TTC due to (i) acute onset of symptoms, (ii) typical apical ballooning, (iii) absence of significant coronary disease, and (iv) complete remission on 4-month follow-up. The patients underwent coronary angiography (CAG), echocardiography, cardiac magnetic resonance imaging (CMR), and (13)NH3/(82)Rb positron emission tomography (PET) in the acute state and-except CAG-on follow-up. Patients initially had severe heart failure, mid/apical oedema but no infarction, and a rise in cardiac biomarkers. On initial perfusion PET imaging, eight patients appeared to have normal, whereas 17 patients had impaired LV perfusion. In the latter, flow in the basal region was increased in the acute state (1.5 ± 0.1 vs. 1.2 ± 0.1 mL/g/minRPP-corrected, P < 0.01), whereas midventricular (1.7 ± 0.1 vs. 1.6 ± 0.1 mL/g/minRPP-corrected, P = 0.21) and apical (1.4 ± 0.1 vs. 1.5 ± 0.1 mL/g/minRPP-corrected, P = 0.36) flow was unchanged between acute and follow-up, and within normal range. CONCLUSION: Our results suggest an abnormal LV perfusion distribution in the acute state of TTC with basal hyperperfusion and a normoperfused akinetic region. The proportion of patients without visualized perfusion abnormalities in the acute state may represent a subgroup with fast remission.

The clinical value of cardiac sympathetic imaging in heart failure.

The autonomic nervous system plays an important role in the pathology of heart failure. The single-photon emission computed tomography tracer iodine-123-metaiodobenzylguanidine ((123) I-MIBG) can be used to investigate the activity of the predominant neurotransmitter of the sympathetic nervous system, norepinephrine. Also, positron emission tomography tracers are being developed for the same purpose. With (123) I-MIBG as a starting point, this brief review introduces the modalities used for cardiac sympathetic imaging.

Takotsubo cardiomyopathy, a two-stage recovery of left ventricular systolic and diastolic function as determined by cardiac magnetic resonance imaging.

AIMS: Takotsubo cardiomyopathy (TTC) is an entity mimicking acute myocardial infarction, characterized by transient severe systolic heart failure. Echocardiographic studies suggest that diastolic dysfunction is present in TTC at presentation; however, no reports exist regarding the time course of left ventricular (LV) recovery. This study describes the recovery of LV systolic and diastolic function in TTC. We hypothesized that, in TTC, there is diastolic dysfunction at admission, and that recovery is delayed compared with systolic function. METHODS AND RESULTS: We enrolled (consecutively 2010-12) 16 patients (mean age 66, range 39-84 years) diagnosed with TTC and 20 healthy matched controls. We performed cardiac magnetic resonance imaging (CMR) at admission, pre-discharge, and 3-month follow-up. Diastolic function was assessed by LV peak filling rate (LVPFR) and left atrial (LA) emptying volumes. At admission, LV ejection fraction was low, increased at pre-discharge (37 ± 6 vs. 58 ± 6%, P < 0.001), and normalized at follow-up (to 65 ± 5%, P = 0.01). LVPFR did not increase during hospitalization (80 ± 3 vs. 89 ± 4 mL/s/m(2), P = 0.21), but was normalized at follow-up (to 206 ± 19, P < 0.001; controls, 214 ± 13, P = 0.23). During hospitalization, LA passive emptying volume remained low (6 ± 2 vs. 8 ± 3 mL/m(2), P = 0.05) and LA active emptying volume remained high (17 ± 3 vs. 16 ± 3 mL/m(2), P = 0.71), whereas LA conduit volume increased (7 ± 3 vs. 23 ± 4 mL/m(2), P < 0.001). T2-weighted imaging demonstrated non-coronary distributed apical oedema without contrast enhancement. CONCLUSION: Patients with TTC undergo fast systolic recovery. However, at discharge, profound diastolic dysfunction is demonstrated by CMR. At follow-up, both LV systolic and diastolic function is normalized in patients with recovered TTC.

Cardiac 99mTc sestamibi SPECT and ¹8F FDG PET as viability markers in Takotsubo cardiomyopathy.

In patients with heart failure (HF) due to coronary disease, a combined evaluation of perfusion and glucose metabolism by cardiac single photon emission computed tomography (SPECT)/positron emission tomography (PET) can be used to distinguish viable from non-viable myocardium, and current guidelines recommend cardiac SPECT and fluorodeoxyglucose (FDG) PET for viability assessment. Takotsubo cardiomyopathy (TTC) is a disease characterized by acute but reversible HF leaving no scarring. To explore how robust the semi-quantitative viability criteria used in cardiac SPECT and FDG PET stands their ground in a population with TTC. From 1 September 2009 to 1 October 2012, 24 patients suspected of TTC were enrolled in a multimodality cardiac imaging research project. Echocardiography, (99m)Tc SPECT, and (18)F FDG PET were performed during the acute admission and at follow-up 4 months later. Nineteen patients had a final diagnosis of TTC consistent with Mayo Clinic Diagnostic Criteria. Three of these patients were excluded from further analysis, since wall motion abnormalities were not persistent at the time of nuclear imaging. The remaining sixteen patients exhibited a distinct pattern with HF, "apical ballooning" and a perfusion-metabolism defect in the midventricular/apical region. When viability criteria were applied, they identified significant scarring/limited hibernation in the akinetic part of the left ventricle. However, full recovery was found in all TTC patients on follow-up. Using the current guideline-endorsed viability criteria for semiquantitative cardiac SPECT and FDG PET, these modalities failed to demonstrate the presence of viability in the acute state of TTC.