Takotsubo cardiomyopathy: overview

Takotsubo cardiomyopathy (TTC) is a unique acute syndrome characterized by transient left ventricular systolic dysfunction in the absence of significant coronary artery disease, occurring mostly in postmenopausal women after emotional and/or physical stress. Given the nonspecific symptoms and signs, a high clinical index of suspicion is necessary to detect the disease in different clinical settings and scenarios. Noninvasive multimodality imaging may be useful to distinguish this cardiomyopathy from other acute cardiac and thoracic diseases. Coronary angiography remains, however, mandatory to differentiate TTC from acute coronary syndromes. This article reviews the clinical features and management of TTC and some new insights.

Takotsubo cardiomyopathy: an integrated multi-imaging approach

Takotsubo cardiomyopathy (TTC) is a distinct clinical entity characterized by the presence of transient left ventricular wall dysfunction without significant culprit obstructive coronary artery disease. Invasive coronary angiography and ventriculography are the 'gold standard' for definitive diagnosis, with an integrated multi-modality imaging approach offering advantages in various clinical scenarios. Echocardiography is a widely available, first-line, non-invasive imaging technique appropriate both in emergency setting to confirm diagnosis, assess for various potential acute complications, and in serial follow-up to track myocardial recovery. Cardiac magnetic resonance (CMR) may be helpful to discriminate TTC from other acute cardiac syndromes with troponin elevation and ventricular dysfunction. Echocardiography, CMR, and nuclear imaging may also provide new insights into possible underlying pathophysiological mechanisms, and myocardial (123)I-metaiodobenzyl-guanidine imaging may have a role for retrospective diagnosis in the subacute phase of late-presenting cases. The potential diagnostic role of coronary computed tomography angiography in the emergency room requires a further study.

A signature of circulating microRNAs differentiates takotsubo cardiomyopathy from acute myocardial infarction

Aims

Takotsubo cardiomyopathy (TTC) remains a potentially life-threatening disease, which is clinically indistinguishable from acute myocardial infarction (MI). Today, no established biomarkers are available for the early diagnosis of TTC and differentiation from MI. MicroRNAs (miRNAs/miRs) emerge as promising sensitive and specific biomarkers for cardiovascular disease. Thus, we sought to identify circulating miRNAs suitable for diagnosis of acute TTC and for distinguishing TTC from acute MI.

Methods and results

After miRNA profiling, eight miRNAs were selected for verification by real-time quantitative reverse transcription polymerase chain reaction in patients with TTC (n = 36), ST-segment elevation acute myocardial infarction (STEMI, n = 27), and healthy controls (n = 28). We quantitatively confirmed up-regulation of miR-16 and miR-26a in patients with TTC compared with healthy subjects (both, P < 0.001), and up-regulation of miR-16, miR-26a, and let-7f compared with STEMI patients (P < 0.0001, P < 0.05, and P < 0.05, respectively). Consistent with previous publications, cardiac specific miR-1 and miR-133a were up-regulated in STEMI patients compared with healthy controls (both, P < 0.0001). Moreover, miR-133a was substantially increased in patients with STEMI compared with TTC (P < 0.05). A unique signature comprising miR-1, miR-16, miR-26a, and miR-133a differentiated TTC from healthy subjects [area under the curve (AUC) 0.835, 95% CI 0.733–0.937, P < 0.0001] and from STEMI patients (AUC 0.881, 95% CI 0.793–0.968, P < 0.0001). This signature yielded a sensitivity of 74.19% and a specificity of 78.57% for TTC vs. healthy subjects, and a sensitivity of 96.77% and a specificity of 70.37% for TTC vs. STEMI patients. Additionally, we noticed a decrease of the endothelin-1 (ET-1)-regulating miRNA-125a-5p in parallel with a robust increase of ET-1 plasma levels in TTC compared with healthy subjects (P < 0.05).

Conclusion

The present study for the first time describes a signature of four circulating miRNAs as a robust biomarker to distinguish TTC from STEMI patients. The significant up-regulation of these stress- and depression-related miRNAs suggests a close connection of TTC with neuropsychiatric disorders. Moreover, decreased levels of miRNA125a-5p as well as increased plasma levels of its target ET-1 are in line with the microvascular spasm hypothesis of the TTC pathomechanism.

[Cardiac magnetic resonance tomography in the diagnostics of restrictive and unclassified cardiopathies]

CLINICAL/METHODICAL ISSUE

Besides ischemic heart disease cardiomyopathies are common causes of heart failure and sudden cardiac death.

STANDARD RADIOLOGICAL METHODS

The diagnostic spectrum in cardiomyopathies comprises non-invasive and invasive examination techniques.

METHODICAL INNOVATIONS

The exact verification of certain cardiomyopathies necessitates knowledge of the latest classification of cardiomyopathies as well as dedicated examination protocols.

PERFORMANCE

Modern imaging modalities, such as echocardiography and cardiac magnetic resonance imaging (MRI) have emerged as useful imaging tools in the investigation of patients suspected of having many different types of cardiomyopathies.

ACHIEVEMENTS

Based on a better understanding of the underlying pathophysiology several diagnostic criteria have been defined using cardiac MRI. In particular there is an increasing importance of cardiac MRI in the description of patients with restrictive and unclassified cardiomyopathies.

PRACTICAL RECOMMENDATIONS

Echocardiography still remains the modality of choice in the diagnostics of unclear left ventricular heart failure. Further diagnostic work-up should include cardiac MRI in case of any lack of clarity.

Spontaneous coronary artery dissection triggered post-ischemic myocardial stunning and takotsubo syndrome: two different names for the same condition

An acute coronary ischemic insult may "cause" prolonged post-ischemic myocardial stunning. In spite of being a major stress factor, acute coronary syndrome is regarded as an exclusion criterion for takotsubo syndrome. We describe the case of a 39-year-old female patient presented with anterior ST-elevation myocardial infarction. Emergency coronary angiography revealed spontaneous coronary artery dissection confirmed with intravascular ultrasound examination. The patient developed clinical, angiographic and cardiac image features consistent with both post-ischemic myocardial stunning and takotsubo syndrome. Complete healing of the coronary dissection occurred with conservative treatment. There was also resolution of the greatest part of the left ventricular dysfunction. The findings in the present case indicate that the post-ischemic myocardial stunning and takotsubo syndrome are two different names for the same clinical condition and that the acute coronary syndrome triggers rather than excludes takotsubo syndrome.

Apicobasal gradient of left ventricular myocardial edema underlies transient T-wave inversion and QT interval prolongation (Wellens' ECG pattern) in Tako-Tsubo cardiomyopathy

BACKGROUND

Tako-Tsubo cardiomyopathy (TTC) presents with chest pain, ST-segment elevation followed by T-wave inversion and QT interval prolongation (Wellens' electrocardiographic [ECG] pattern), and left ventricular dysfunction, which may mimic an acute coronary syndrome.

OBJECTIVE

To assess the pathophysiologic basis of the Wellens' ECG pattern in TTC by characterization of underlying myocardial changes by using cardiac magnetic resonance (CMR).

METHODS

The study population included 20 consecutive patients with TTC (95% women; mean age 65.3 ± 10.4 years) who underwent CMR studies both in the initial phase and after 3-month follow-up by using a protocol that included cine images, T2-weighted sequences for myocardial edema, and post-contrast sequences for late gadolinium enhancement. Quantitative ECG indices of repolarization, such as maximal amplitude of negative T waves, sum of the amplitudes of negative T waves, and maximum corrected QT interval (QTc max), were correlated to CMR findings.

RESULTS

At the time of initial CMR study, there was a significant linear correlation between the apicobasal ratio of T2-weighted signal intensity for myocardial edema and the maximal amplitude of negative T waves (ρ = 0.498; P = .02), sum of the amplitudes of negative T waves (ρ = 0.483; P = .03), and maximum corrected QT interval (ρ = 0.520; P = .02). Repolarization indices were unrelated to either late gadolinium enhancement or quantitative cine parameters. Wellens' ECG abnormalities and myocardial edema showed a parallel time course of development and resolution on initial and follow-up CMR studies.

CONCLUSIONS

Our study results show that the ischemic-like Wellens' ECG pattern in TTC coincides and quantitatively correlates with the apicobasal gradient of myocardial edema as evidenced by using CMR. Dynamic negative T waves and QTc prolongation are likely to reflect the edema-induced transient inhomogeneity and dispersion of repolarization between apical and basal left ventricular regions.

Diagnostic and prognostic value of cardiovascular magnetic resonance in non-ischaemic cardiomyopathies

Cardiovascular Magnetic Resonance (CMR) is recognised as a valuable clinical tool which in a single scan setting can assess ventricular volumes and function, myocardial fibrosis, iron loading, flow quantification, tissue characterisation and myocardial perfusion imaging. The advent of CMR using extrinsic and intrinsic contrast-enhanced protocols for tissue characterisation have dramatically changed the non-invasive work-up of patients with suspected or known cardiomyopathy. Although the technique initially focused on the in vivo identification of myocardial necrosis through the late gadolinium enhancement (LGE) technique, recent work highlighted the ability of CMR to provide more detailed in vivo tissue characterisation to help establish a differential diagnosis of the underlying aetiology, to exclude an ischaemic substrate and to provide important prognostic markers. The potential application of CMR in the clinical approach of a patient with suspected non-ischaemic cardiomyopathy is discussed in this review.

Hyponatremia--an unusual trigger of Takotsubo cardiomyopathy

Takotsubo cardiomyopathy is an acute cardiac entity with clinical manifestations similar to myocardial infarction, accounting for 1-2% of acute coronary syndrome admissions. Its underlying pathophysiology is not yet well established. It is usually associated with acute physical or emotional stress, but the list of potential triggers has grown as the condition attracts the attention of the medical community. In order to diagnose the condition correctly and to gain new insights into it, we need to know its potential triggers as well as its clinical presentation and diagnostic criteria. We report a case of takotsubo cardiomyopathy triggered by hyponatremia.

Investigation of cardiomyopathy using cardiac magnetic resonance imaging part 2: Rare phenotypes

Cardiac magnetic resonance imaging (CMRI) has emerged as a useful tertiary imaging tool in the investigation of patients suspected of many different types of cardiomyopathies. CMRI images are now of a sufficiently robust quality to enable high spatial and temporal resolution image acquisition. This has led to CMRI becoming an effective non-invasive imaging tool for many cardiomyopathies. In this two-part review we outline the typical sequences used to image cardiomyopathy and present the imaging spectrum of cardiomyopathy. Part I focused on the current classification of cardiomyopathy, the basic CMRI sequences used in evaluating cardiomyopathy and the imaging spectrum of common phenotypes. Part II illustrates the imaging spectrum of the more rare phenotypes.

Scintigraphic imaging in Tako-Tsubo cardiomyopathy

Tako-Tsubo cardiomyopathy (TTC, stress cardiomyopathy) is more common in elderly women and its symptoms can be deceptively similar to those of acute myocardial infarction. Although coronary arteries appear normal on coronary angiograms, a shape like a Tako-Tsubo (a Japanese fishing pot for trapping octopuses) can be observed on left ventriculogram. TTC is generally considered to be a trigger for sudden cardiac death. The onset mechanism of TTC is still controversial. Catecholamine cardiotoxicity and/or coronary circulation disturbance due to coronary microvascular spasm and/or neurogenic stunned myocardium as a result of autonomic imbalance are considered to be the most likely causes. In this review, we assess the usefulness of myocardial scintigraphic imaging in TTC patients on the basis of the results obtained from earlier studies and case reports in order to establish a deeper understanding of the pathophysiological mechanism of this syndrome.

Myocardial edema imaging by cardiovascular magnetic resonance: current status and future potential

Cardiovascular magnetic resonance (CMR) imaging is widely established, free of radioactive material or ionizing radiation, and the accepted noninvasive gold standard for numerous noninvasive cardiac markers. Using a technique called T2-weighted imaging, CMR can be used to assess myocardial edema as a reliable marker for acute, potentially reversible myocardial injury. Contrast agents are not required as the myocardial free water content affects the magnetic properties of the tissue, thus providing inherent image contrast. In this review, we illustrate the utility of T2-weighted techniques in the assessment of myocardial edema in a range of clinical scenarios. The detection of myocardial edema is clinically relevant in many acute settings and may be further helpful to better understand the pathophysiology of many non-acute clinical diseases. Currently, T2-weighted CMR represents the only imaging modality that can accurately depict and quantify the presence of myocardial edema in a noninvasive fashion. Thus, T2-weighted imaging should be included in a comprehensive CMR imaging protocol, especially if an acute injury is suspected.

Cardiac MR imaging of nonischemic cardiomyopathies: imaging protocols and spectra of appearances

Recent technologic advances in cardiac magnetic resonance (MR) imaging have resulted in images with high spatial and temporal resolution and excellent myocardial tissue characterization. Cardiac MR is a valuable imaging technique for detection and assessment of the morphology and functional characteristics of the nonischemic cardiomyopathy. It has gained acceptance as a standalone imaging modality that can provide further information beyond the capabilities of traditional modalities such as echocardiography and angiography. Black-blood fast spin-echo MR images allow morphologic assessment of the heart with high spatial resolution, while T2-weighted MR images can depict acute myocardial edema. Contrast material-enhanced images can depict and be used to quantify myocardial edema, infiltration, and fibrosis. This review presents recommended cardiac MR protocols for and the spectrum of imaging appearances of the nonischemic cardiomyopathies.

Prevalence and signal characteristics of late gadolinium enhancement on contrast-enhanced magnetic resonance imaging in patients with takotsubo cardiomyopathy

BACKGROUND

To determine the prevalence and signal intensity (SI) characteristics of late gadolinium enhancement (LGE) on magnetic resonance imaging (MRI) in takotsubo cardiomyopathy (TC).

METHODS AND RESULTS

Cine, black-blood T2-weighted and LGE MR images were acquired in 23 patients with TC within 72 h of onset. Wall motion abnormality (WMA), edema and LGE were evaluated with a 16-segment model. The SI characteristics of LGE were analyzed using SI distribution in remote normal segments as reference. Follow-up MRI was performed 3 months later. Retrospective analysis of LGE MRI was also performed in 10 patients with acute myocardial infarction (AMI) to compare the SI characteristics between TC and AMI. In acute phase, WMA and edema were observed in 236 (64%) and 205 (56%) of 368 segments. LGE was observed in 10 (2.7%) of 368 segments and in 5 (22%) of 23 patients. All LGE lesions in TC exhibited transmural enhancement. The contrast-to-noise ratio (CNR) in TC was significantly lower than that of AMI (3.1±0.3 standard deviations (SD) vs. 6.1±1.2 SD, P<0.01), and CNR value of 4 was useful for distinguishing TC from AMI. Both LGE and WMA disappeared within 12 months.

CONCLUSIONS

Grey myocardial signal on LGE MRI may be observed in patients with TC. However, the extent of LGE is substantially less than that of WMA and edema, and disappears within 12 months.

Takotsubo cardiomyopathy: utility of cardiac computed tomography angiography for acute diagnosis

Takotsubo (stress) cardiomyopathy may present as acute cardiovascular collapse, simulating an acute coronary syndrome or other emergencies such as pulmonary embolism or aortic dissection. The diagnosis relies on demonstration of characteristic wall motion abnormalities in the absence of obstructive coronary lesions and is typically diagnosed with cardiac catheterization. Cardiac computed tomography angiography is well suited to use in the emergency setting to diagnose or exclude thoracic cardiovascular events. We describe a case of Takotsubo cardiomyopathy that occurred during induction of anesthesia, in which emergent cardiac computed tomography angiography confirmed the diagnosis and excluded other potential etiologies of disease.

The role of cardiac magnetic resonance imaging in the assessment of non-ischemic cardiomyopathy

Cardiovascular magnetic resonance imaging (CMR) plays an increasing role in the assessment of patients with various cardiovascular disorders. Given its enhanced spatial resolution, improved tissue characterization, and lack of ionizing radiation, it has become the test of choice in the evaluation of patients with new-onset cardiomyopathy of unknown etiology. In this paper, we will review the role of CMR in the evaluation of patients with various types of non-ischemic cardiomyopathy.

Improved detection of myocardial involvement in acute inflammatory cardiomyopathies using T2 mapping

BACKGROUND

T2-weighted cardiac magnetic resonance imaging is useful in diagnosing acute inflammatory myocardial diseases, such as myocarditis and tako-tsubo cardiomyopathy (TTCM). We hypothesized that quantitative T2 mapping could better delineate myocardial involvement in these disorders versus T2-weighted imaging.

METHODS AND RESULTS

Thirty patients with suspected myocarditis or TTCM, referred for cardiac magnetic resonance imaging, who met established diagnostic criteria underwent myocardial T2 mapping. T2 values were averaged in involved and remote myocardial segments, both defined by a reviewer blinded to T2 data. In myocarditis, T2 was 65.2±3.2 ms in the involved myocardium versus 53.5±2.1 ms in the remote myocardium (P<0.001). In TTCM, T2 was 65.6±4.0 ms in the involved myocardium versus 53.6±2.7 ms in the remote segments (P<0.001). T2 values were similar across remote myocardial segments in patients and all myocardial segments in controls (P>0.05 for all). T2 maps provided diagnostic data even in patients with difficulty breath holding. A T2 cutoff of 59 ms identified areas of myocardial involvement, with sensitivity and specificity of 94% and 97%, respectively. T2 mapping revealed regions of abnormal T2 beyond those identified by wall motion abnormalities or late gadolinium-enhancement positivity. Conventional T2-weighted short tau inversion recovery images were uninterpretable in 7 patients because of artifact and unremarkable in 2 patients who had elevated T2 values. T2-prepared steady-state-free precession images showed areas of signal hyperintensity in only 17 of 30 patients.

CONCLUSIONS

Quantitative T2 mapping reliably identifies myocardial involvement in patients with myocarditis and TTCM. T2 mapping delineated a greater extent of myocardial disease in both conditions compared with that identified by wall motion abnormalities, T2-weighted short tau inversion recovery imaging, T2-prepared steady-state-free precession, or late gadolinium enhancement. Quantitative T2 mapping warrants consideration as a robust technique to identify myocardial injury in patients with acute myocarditis or TTCM.

Three-dimensional entertainment as a novel cause of takotsubo cardiomyopathy

Takotsubo cardiomyopathy (TC) is an uncommon entity. It is known to occur in the setting of extreme catecholamine release and results in left ventricular dysfunction without evidence of angiographically definable coronary artery disease. There have been no published reports of TC occurring with visual stimuli, specifically 3-dimensional (3D) entertainment. We present a 55-year-old woman who presented to her primary care physician's office with extreme palpitations, nausea, vomiting, and malaise <48 hours after watching a 3D action movie at her local theater. Her electrocardiogram demonstrated ST elevations in aVL and V1, prolonged QTc interval, and T-wave inversions in leads I, II, aVL, and V2-V6. Coronary angiography revealed angiographically normal vessels, elevated left ventricular filling pressures, and decreased ejection fraction with a pattern of apical ballooning. The presumed final diagnosis was TC, likely due to visual-auditory-triggered catecholamine release causing impaired coronary microcirculation.

Evolution of acute coronary syndrome with normal coronary arteries and normal cardiac magnetic resonance imaging

BACKGROUND

Acute coronary syndrome (ACS) with normal coronary angiography is a frequent clinical situation with an uncertain prognosis. Cardiac magnetic resonance imaging (CMRI) is a powerful tool for differential diagnosis between myocardial infarction (MI), acute myocarditis and Tako-tsubo cardiomyopathy (TTC). Data are sparse regarding the evolution of patients presenting an ACS with normal coronary arteries and normal CMRI.

AIMS

To evaluate the evolution of patients presenting an ACS with normal coronary arteries and normal CMRI, with a 1-year follow-up.

METHODS

Eighty-seven consecutive patients (mean age, 53 years; 40.2% men) presenting an ACS with troponin elevation and normal coronary arteries by angiography were prospectively included. All patients underwent CMRI at 3-Tesla. Adverse events were recorded with 1-year follow-up.

RESULTS

A likely aetiology for the acute clinical presentation was established by CMRI in 63.2% of patients (22.7% MI, 26.4% acute myocarditis, 11.5% TTC). During follow-up, one patient in the MI group had a stroke (1.2%). In the myocarditis group, there was one initial cardiogenic shock, one episode of congestive heart failure (1.2%) and nine patients had recurrent chest pain without troponin elevation (10.3%). Two TTC group patients initially presented with cardiogenic shock (2.4%); there were no other adverse events in this group during follow-up. In the remaining 36.7% patients, no clear diagnosis could be identified by CMRI, and no adverse events occurred during follow-up.

CONCLUSION

CMRI is a useful tool for the management of ACS presenting with normal coronary angiography, as it helps to ascertain the diagnosis and adapt treatment in a large proportion of cases. Nonetheless, patients with no abnormalities identified by CMRI have an excellent evolution.

Morphologic pattern of late gadolinium enhancement in Takotsubo cardiomyopathy detected by early cardiovascular magnetic resonance

BACKGROUND

Takotsubo cardiomyopathy (TTC) presents clinically as an acute coronary syndrome. It is characterized by transient left ventricular wall dyskinesis-akinesis, without significant epicardial coronary lesions. Late gadolinium enhancement (LGE) sequences on cardiac magnetic resonance (CMR) allow to clarify the pathophysiology in patients with chest pain, elevated troponin, and normal epicardial coronary arteries; in patients with TTC, previous studies have shown absence of LGE.

HYPOTHESIS

Early CMR in Takotsubo patients could show a morphological pattern of LGE improving clinical diagnosis.

METHODS

Between January 2005 and January 2007, 8 consecutive patients with TTC criteria underwent CMR within the first 3 days of admission. Cine, T2-weighted, and LGE images were acquired. Patient follow-up included clinical exam and imaging techniques: echocardiogram on days 3, 7, 30, and 60, and CMR at 3 months.

RESULTS

Six patients had experienced a previous stressful situation. No significant lesions were found on coronary angiography, and wall motion improvement was noted at 15 (7-30) days. Median EFs at admission and recovery were 46.5% and 65%, respectively. Dyskinesis was midapical in 6 cases, apical in 1 case, and mid-ventricular in 1 case. Late gadolinium enhancement showed mild hyperenhancement in areas of abnormal wall motion, whereas normal segments had no contrast enhancement. On follow-up CMR, wall motion was normal without late enhancement.

CONCLUSIONS

Early CMR in TTC demonstrates a special morphological pattern of late gadolinium uptake that might correspond to localized inflammation and edema in the affected area, suggesting diffuse microcirculation damage rather than epicardial vessel involvement.

Dual manganese-enhanced and delayed gadolinium-enhanced MRI detects myocardial border zone injury in a pig ischemia-reperfusion model

BACKGROUND

Gadolinium (Gd)-based delayed-enhancement MRI (DEMRI) identifies nonviable myocardium but is nonspecific and may overestimate nonviable territory. Manganese (Mn(2+))-enhanced MRI (MEMRI) denotes specific Mn(2+) uptake into viable cardiomyocytes. We performed a dual-contrast myocardial assessment in a porcine ischemia-reperfusion (IR) model to test the hypothesis that combined DEMRI and MEMRI identifies viable infarct border zone (BZ) myocardium in vivo.

METHODS AND RESULTS

Sixty-minute left anterior descending coronary artery IR injury was induced in 13 adult swine. Twenty-one days post-IR, 3-T cardiac MRI was performed. MEMRI was obtained after injection of 0.7 mL/kg Mn(2+) contrast agent. DEMRI was then acquired after injection of 0.2 mmol/kg Gd. Left ventricular (LV) mass, infarct, and function were analyzed. Subtraction of MEMRI defect from DEMRI signal identified injured BZ myocardium. Explanted hearts were analyzed by 2,3,5-triphenyltetrazolium chloride stain and tissue electron microscopy to compare infarct, BZ, and remote myocardium. Average LV ejection fraction was reduced (30±7%). MEMRI and DEMRI infarct volumes correlated with 2,3,5-triphenyltetrazolium chloride stain analysis (MEMRI, r=0.78; DEMRI, r=0.75; P<0.004). MEMRI infarct volume percentage was significantly lower than that of DEMRI (14±4% versus 23±4%; P<0.05). BZ MEMRI signal-to-noise ratio (SNR) was intermediate to remote and core infarct SNR (7.5±2.8 versus 13.2±3.4 and 2.9±1.6; P<0.0001), and DEMRI BZ SNR tended to be intermediate to remote and core infarct SNR (8.4±5.4 versus 3.3±0.6 and 14.3±6.6; P>0.05). Tissue electron microscopy analysis exhibited preserved cell structure in BZ cardiomyocytes despite transmural DEMRI enhancement.

CONCLUSIONS

The dual-contrast MEMRI-DEMRI detects BZ viability within DEMRI infarct zones. This approach may identify injured, at-risk myocardium in ischemic cardiomyopathy.

The use of cardiovascular magnetic resonance in acute myocardial infarction

Acute myocardial infarction (MI) results in reversible and irreversible injury to the myocardium, including stunning, edema, myocyte necrosis, and microvascular obstruction. Because of its unique tissue characterization capabilities, cardiovascular magnetic resonance provides a reliable means of visualizing and quantifying the extent of these injuries. Such characterization is readily achieved through a comprehensive examination including function, first-pass perfusion, T2 (edema), and late enhancement imaging sequences. This helps to predict the prognosis, assess the success of reperfusion, detect acute phase complications, localize the area of the acute event, and confirm the diagnosis in clinical scenarios with clinical presentations similar to that of acute MI. Finally, one emerging application is the role cardiovascular magnetic resonance (CMR) may play in detecting some infarcts very early on in their evolution. This article covers the established and emerging clinical applications of CMR in the settings of reperfused and nonreperfused infarcts and in acute myocardial ischemia, the step immediately preceding actual irreversible injury.

Tachycardia-induced cardiomyopathy: evaluation and therapeutic options

Tachycardia-induced cardiomyopathy is caused by sustained rapid ventricular rates and is one of the well-known forms of reversible myocardial dysfunction. The diagnosis is usually made retrospectively after marked improvement in systolic function is noted following control of the heart rate. Physicians should be aware that patients with seemingly idiopathic systolic dysfunction may have tachycardia-induced cardiomyopathy and that controlling the heart rate may result in improvement or even complete restoration of systolic function.

Left ventricular contraction patterns in patients with suspected acute coronary syndrome and normal coronary angiograms: a new look at the takotsubo syndrome

BACKGROUND

Original descriptions of the takotsubo syndrome (TS) included a characteristic left ventricular (LV) contraction pattern, "apical ballooning." Recently, several reports have associated contraction patterns not strictly conforming to the original description with TS. The specifics of the contraction pattern seem to set TS apart from the much larger population of patients with acute coronary syndrome (ACS) but no obstructive coronary artery disease (OCAD). This study was undertaken to compare patients with midventricular and apical dysfunction with those with other LV contraction patterns.

HYPOTHESIS

If TS can present with a variety of patterns of LV dysfunction, then both those with and those without the pattern should have the clinical components previously assigned to the syndrome.

METHODS

We studied LV contraction patterns in consecutive ACS patients referred for consideration of emergent or urgent percutaneous coronary intervention.

RESULTS

Of the 893 patients evaluated in 2008, we excluded 862 on the basis of OCAD, preexisting LV dysfunction, or an obvious alternative cause of symptoms. The remaining 31 (3.5%) also had no OCAD but manifested an LV contraction abnormality. We compared the 15 patients (1.7%) whose ventriculograms met criteria for TS with the 16 patients (1.8%) whose did not. The most common alternative pattern was global hypokinesis, followed by a variety of segmental contraction abnormalities. Patients with the TS pattern were older and had evidence of greater myocardial injury. More than 85% were women.

CONCLUSIONS

The TS pattern identifies a distinct subset of ACS patients with a remarkable predominance of postmenopausal women and is therefore fundamental to the definition of this entity. This distinctive facet of the syndrome is likely to be an important clue to its pathogenesis. We did not encounter patients with other patterns of LV dysfunction that could be thought to represent stress-induced cardiomyopathy. Copyright © 2011 Wiley Periodicals, Inc. The authors have no funding, financial relationships, or conflicts of interest to disclose.

Myocardial infarction with angiographically normal coronary arteries

Myocardial Infarction with Normal Coronary Arteries (MINCA) is an important subgroup of myocardial infarction with a frequency of at least 3-4% of all myocardial infarctions. The interest and awareness of MINCA have increased recently due to the frequent use of coronary angiography, the description of Takotsubo stress cardiomyopathy and new sensitive troponin assays. Since myocarditis may mimic myocardial infarction it is essential to exclude this in patients with myocardial infarction with angiographically normal coronary arteries. Cardiac magnetic resonance imaging is a cornerstone not only to establish the diagnosis but also an important tool in the search for different causes of myocardial damage. In the future, atherosclerotic burden, hemostatic function, characterization of stressors and inflammation will be important targets for research in this group of patients.

Acute chest pain: the role of MR imaging and MR angiography

MR imaging (MRI) and MR angiography (MRA) have gained a high level of diagnostic accuracy in cardiovascular disease. MRI in cardiac disease has been established as the non-invasive standard of reference in many pathologies. However, in acute chest pain the situation is somewhat special since many of the patients presenting in the emergency department suffer from potentially life-threatening disease including acute coronary syndrome, pulmonary embolism, and acute aortic syndrome. Those patients need a fast and definitive evaluation under continuous monitoring of vital parameters. Due to those requirements MRI seems to be less suitable compared to X-ray coronary angiography and multislice computed tomography angiography (CTA). However, MRI allows for a comprehensive assessment of all clinically stable patients providing unique information on the cardiovascular system including ischemia, inflammation and function. Furthermore, MRI and MRA are considered the method of choice in patients with contraindications to CTA and for regular follow-up in known aortic disease. This review addresses specific features of MRI and MRA for different cardiovascular conditions presenting with acute chest pain.

Cardiac magnetic resonance imaging for the diagnosis of patients presenting with chest pain, raised troponin, and unobstructed coronary arteries

To evaluate the incremental diagnostic and prognostic value of cardiac magnetic resonance (CMR) in patients with chest pain, raised troponin and unobstructed coronary arteries, and to compare subsequent event rates between diagnostic groups. 130 patients (mean age: 54 ± 17) presenting with troponin-positive acute chest pain and unobstructed coronary arteries were included. All patients were managed according to European Society of Cardiology guidelines, including echocardiography, and had CMR within 6.2 ± 5.3 days of presentation. During follow-up, major adverse cardiovascular events (MACE) were recorded. CMR provided a diagnosis in 100 of 130 patients (76.9%), with the remaining 30 (23.1%) having a normal examination. CMR diagnosed 37 (28.5%) acute myocardial infarctions, 34 (26.1%) myocarditis, 28 (21.5%) apical ballooning syndromes and 1 (0.8%) hypertrophic cardiomyopathy. When a single diagnosis was suspected by the referring physician, CMR validated this diagnosis in 32 patients (76.2%). CMR provided a formal diagnosis in 61 patients (69.3%) in which the clinical diagnosis was uncertain between at least two possibilities. CMR corrected a wrong diagnosis in 10 patients (7.7%). CMR-suggested diagnosis led to a modification of therapy in 42 patients (32.3%). Median follow-up was 34 months (interquartile range 24-49) in 124 patients. Sixteen patients (12.9%) experienced MACE. MACE rate was not different between patients with a conclusive CMR and normal CMR. In patients with acute troponin-positive chest pain and unobstructed coronary arteries, early CMR has important diagnostic and therapeutic implications. However its association with occurrence of MACE during mid term follow-up was not obvious.

T2-weighted cardiovascular magnetic resonance in acute cardiac disease

Cardiovascular magnetic resonance (CMR) using T2-weighted sequences can visualize myocardial edema. When compared to previous protocols, newer pulse sequences with substantially improved image quality have increased its clinical utility. The assessment of myocardial edema provides useful incremental diagnostic and prognostic information in a variety of clinical settings associated with acute myocardial injury. In patients with acute chest pain, T2-weighted CMR is able to identify acute or recent myocardial ischemic injury and has been employed to distinguish acute coronary syndrome (ACS) from non-ACS as well as acute from chronic myocardial infarction.T2-weighted CMR can also be used to determine the area at risk in reperfused and non-reperfused infarction. When combined with contrast-enhanced imaging, the salvaged area and thus the success of early coronary revascularization can be quantified. Strong evidence for the prognostic value of myocardial salvage has enabled its use as a primary endpoint in clinical trials. The present article reviews the current evidence and clinical applications for T2-weighted CMR in acute cardiac disease and gives an outlook on future developments."The principle of all things is water"Thales of Miletus (624 BC - 546 BC).

A rare case report of mid cavitary takotsubo: the role of magnetic resonance imaging

This is a case report of a female presenting originally with clinical picture of acute coronary syndrome and depressed left ventricular function with no angiographic evidence of coronary artery disease with mid cavitary akinesis and basal as well as apical hyperkinesis after emotional stresses identified by multi-imaging modalities to be mid cavitary Takotsubo. The Incidence and the prevalence of apical ballooning syndrome (Takotsubo) is on the rise with more reports in the literature; however, mid cavitary Takotsubo remains rare and raises questions more than answers as to the reason behind the mid cavitary localization in some patients versus apical involvement.

Arrhythmia occurrence with takotsubo cardiomyopathy: a literature review

AIMS

Takotsubo cardiomyopathy (TC) or the apical ballooning syndrome is a reversible cardiomyopathy mimicking acute myocardial infarction (AMI). Although malignant arrhythmia is considered less likely to occur in TC than with AMI, sporadic reports of malignant arrhythmia with TC, however, have been reported. We reviewed the medical literature on TC and arrhythmias and describe in the summary the reported findings and discuss possible specific scenarios where arrhythmia may be more likely in patients with TC.

METHODS AND RESULTS

Articles were identified on PubMed using the MeSH terms 'Takotsubo Cardiomyopathy' or 'Apical Ballooning Syndrome'. Seventy-four unique case series with five or more TC patients were identified, with a cumulative total of 1876 cases. Twelve series (242 cases) were excluded because Mayo criteria were not met. Twenty-five series (816 cases, 43.5%) reported on arrhythmia and were included in the analysis.

CONCLUSION

Areas for further prospective study include the duration and mechanism of residual risk and optimal risk stratification and modification. The current state of evidence would support beta-blockers in the acute setting to control tachyarrhythmia, although there is little evidence to support their use beyond convalescence when used for this indication alone. Those in heart failure and cardiogenic shock should be managed with established evidence-based therapies for these conditions. The use of internal defibrillators in TC requires consideration only on a case-by-case basis.

Uncharted waters: rare and unclassified cardiomyopathies characterized on cardiac magnetic resonance imaging

Cardiac magnetic resonance imaging (CMR) has undergone considerable technology advances in recent years, so that it is now entering into mainstream cardiac imaging practice. In particular, CMR is proving to be a valuable imaging tool in the detection, morphological assessment and functional assessment of cardiomyopathies. Although our understanding of this broad group of heart disorders continues to expand, it is an evolving group of entities, with the rarer cardiomyopathies remaining poorly understood or even unclassified. In this review, we describe the clinical and pathophysiological aspects of several of the rare/unclassified cardiomyopathies and their appearance on CMR.

Stress cardiomyopathy

Recently, an increasing number of cases of stress cardiomyopathy, mainly occurring in elderly women, have been documented in many parts of the world. In Japan, this disease is known as takotsubo cardiomyopathy (named after the fishing pot used for trapping octopus). Symptoms of this condition are akin to those of acute myocardial infarction, but no obstructive lesions are found in the coronary arteries, and left ventricular apical ballooning is present. Stress cardiomyopathy is now a well-recognized cause of acute heart failure, lethal ventricular arrhythmias, and ventricular rupture. Although the precise mechanism of onset of this condition is still controversial, two major pathogenic mechanisms have been proposed: catecholamine cardiotoxicity and neurogenic stunned myocardium. We summarize the findings of studies conducted to date on stress cardiomyopathy-from bench to bedside and bedside to bench.