The electrocardiographic paradox of tako-tsubo cardiomyopathy–comparison with acute ischemic syndromes and consideration of molecular biology and electrophysiology to understand the electrical-mechanical mismatching

Broken Heart Syndrome: Evolving Molecular Mechanisms and Principles of Management

Broken Heart Syndrome, also known as Takotsubo Syndrome (TS), is sudden and transient dysfunction of the left and/or right ventricle which often mimics Acute Coronary Syndrome (ACS). Japan was the first country to describe this syndrome in the 1990s, and since then it has received a lot of attention from researchers all around the world. Although TS was once thought to be a harmless condition, recent evidence suggests that it may be linked to serious complications and mortality on par with Acute Coronary Syndrome (ACS). The understanding of TS has evolved over the past few years. However, its exact etiology is still poorly understood. It can be classified into two main types: Primary and Secondary TS. Primary TS occurs when the symptoms of myocardial damage, which is typically preceded by emotional stress, are the reason for hospitalization. Secondary TS is seen in patients hospitalized for some other medical, surgical, obstetric, anesthetic, or psychiatric conditions, and the dysfunction develops as a secondary complication due to the activation of the sympathetic nervous system and the release of catecholamines. The etiopathogenesis is now proposed to include adrenergic hormones/stress, decreased estrogen levels, altered microcirculation, endothelial dysfunction, altered inflammatory response via cardiac macrophages, and disturbances in the brain-heart axis. The role of genetics in disease progression is becoming the focus of several upcoming studies. This review focuses on potential pathophysiological mechanisms for reversible myocardial dysfunction observed in TS, and comprehensively describes its epidemiology, clinical presentation, novel diagnostic biomarkers, and evolving principles of management. We advocate for more research into molecular mechanisms and promote the application of current evidence for precise individualized treatment.

The Exact Definition of the Boundary between the Rapid and Slow Ejection Phases on ECGs and Accurate Location of the j Point

The aim of the study was to describe the boundary between the phases of rapid and slow ejection in the cardiac cycle and to define the exact location of the j point on ECGs.

Electrocardiographic and Seasonal Patterns Allow Accurate Differentiation of Tako-Tsubo Cardiomyopathy from Acute Anterior Myocardial Infarction: Results of a Multicenter Study and Systematic Overview of Available Studies

Background. Though several studies about prevalence, etiology, clinical characteristics, preceding events, clinical management, and outcome of Tako-Tsubo cardiomyopathy (TTC) exist, the current knowledge of TTC remains limited. Objective. In 2006, TTC was classified among the acquired forms of cardiomyopathy. On the basis of pathophysiological implications, we analyzed whether the presence of ST-segment elevation in lead -aVR (i.e., ST-segment depression in aVR) and the simultaneous absence of ST-segment elevation in lead V1 allow a reliable differentiation of TTC from acute anterior ST-segment elevation myocardial infarction (STEMI). A further investigative feature is the seasonal variation of TTC. Since acute cardiovascular events exhibit definite chronobiological patterns, various small studies have tried to evaluate whether this is also the case for TTC. Because results are conflicting, we also conducted a multicenter study and analyzed the findings in context with a systematic overview of available studies. Methods. We compared the ECG patterns of 115 patients with TTC, who were admitted to five large acute cardiac care centers associated with university hospitals in Southwestern Germany between January 2001 and June 2011, with those of 100 patients with acute anterior ST-segment elevation myocardial infarction (STEMI) treated in one of these centers. In addition, we performed a computer-assisted MEDLINE search of the literature from January 2000 to September 2011 and analyzed the chronobiological patterns of available TTC cases, including our TTC cohort. Results. Testing the predefined diagnostic criteria was superior to any other electrocardiographic finding and differentiated TTC from anterior STEMI with a sensitivity of 73%, a specificity of 84%, a positive predictive value of 63%, and a negative predictive value of 89%. Beyond that, the onset of TTC showed a clear variation as a function of season and month. While events occurred most frequently during summer (38.4%, p < 0.01), the event rate was the lowest in autumn (16.4%) and winter (21.9%). Chronobiological analyses on a monthly basis identified a significant annual rhythmic pattern in TTC, which peaked in August (11.9%; p < 0.01) and had its nadir in November (6.3%). Conclusions. Our data illustrate that the ST-segment changes in leads aVR and V1 represent a simple and accurate ECG criterion to differentiate TTC from anterior STEMI in patients who are admitted within 12 h of symptom onset. Similarly, the results of our seasonal analysis indicate a distinct chronobiological variation in TTC occurrence. TTC, thereby, differs from major acute cardiovascular diseases, especially acute myocardial infarction (AMI), which is characterized by winter peaks and troughs in summer. If these results are confirmed in large independent cohorts, they may yield diagnostic implications, changing the regular invasive AMI management in TTC patients.

Takotsubo cardiomyopathy: queries of the current era

: Takotsubo cardiomyopathy (TTS), also known as left ventricular apical ballooning syndrome, is an acute, usually reversible heart failure syndrome that most often affects postmenopausal women experiencing an emotionally stressful event. It is characterized by sudden left ventricular dysfunction and wall motion abnormalities involving the apical and mid segments. TTS has been increasingly recognized in recent years, and more and more information about the pathophysiology, diagnosis, and treatment of these patients has been reported. However, much is still unknown. TTS has a wide variety of clinical subtypes and has been described in several clinical contexts. Moreover, TTS simulates ST-segment elevation myocardial infarction and acute myocarditis, and it can be difficult to obtain a certain diagnosis. As a result, clinical decisions are challenging, and many patients currently receive an inappropriate management strategy. The aim of this review is to critically analyze the evidence about this disease reported in the literature, with particular focus on the pathophysiological processes, the diagnostic elements that can help the clinician differentiate it from other diseases, and the best management of these patients.

International Expert Consensus Document on Takotsubo Syndrome (Part II): Diagnostic Workup, Outcome, and Management

The clinical expert consensus statement on takotsubo syndrome (TTS) part II focuses on the diagnostic workup, outcome, and management. The recommendations are based on interpretation of the limited clinical trial data currently available and experience of international TTS experts. It summarizes the diagnostic approach, which may facilitate correct and timely diagnosis. Furthermore, the document covers areas where controversies still exist in risk stratification and management of TTS. Based on available data the document provides recommendations on optimal care of such patients for practising physicians.

Arrhythmias in takotsubo cardiomyopathy

Acute emotional or physical stress can trigger a catecholamine-mediated myocardial stunning known as takotstubo cardiomyopathy (TCM). Although TCM is generally reversible, it can be associated with significant morbidity, including secondarily to cardiac arrhythmia. Lethal arrhythmias such as heart block, ventricular tachycardia, and ventricular fibrillation have been described. Repolarization abnormalities associated with TCM can lead to characteristic T-wave abnormalities and QT prolongation that place patients at increased risk for ventricular arrhythmia, including torsades de pointes. This article focuses on the arrhythmic complications associated with TCM and explores the underlying etiology of these arrhythmias.

Computational modeling of Takotsubo cardiomyopathy: effect of spatially varying β-adrenergic stimulation in the rat left ventricle

In Takotsubo cardiomyopathy, the left ventricle shows apical ballooning combined with basal hypercontractility. Both clinical observations in humans and recent experimental work on isolated rat ventricular myocytes suggest the dominant mechanisms of this syndrome are related to acute catecholamine overload. However, relating observed differences in single cells to the capacity of such alterations to result in the extreme changes in ventricular shape seen in Takotsubo syndrome is difficult. By using a computational model of the rat left ventricle, we investigate which mechanisms can give rise to the typical shape of the ventricle observed in this syndrome. Three potential dominant mechanisms related to effects of β-adrenergic stimulation were considered: apical-basal variation of calcium transients due to differences in L-type and sarco(endo)plasmic reticulum Ca²⁺-ATPase activation, apical-basal variation of calcium sensitivity due to differences in troponin I phosphorylation, and apical-basal variation in maximal active tension due to, e.g., the negative inotropic effects of p38 MAPK. Furthermore, we investigated the interaction of these spatial variations in the presence of a failing Frank-Starling mechanism. We conclude that a large portion of the apex needs to be affected by severe changes in calcium regulation or contractile function to result in apical ballooning, and smooth linear variation from apex to base is unlikely to result in the typical ventricular shape observed in this syndrome. A failing Frank-Starling mechanism significantly increases apical ballooning at end systole and may be an important additional factor underpinning Takotsubo syndrome.

Pathophysiology of takotsubo syndrome: temporal phases of cardiovascular responses to extreme stress

Takotsubo syndrome (TTS), also known as takotsubo cardiomyopathy, is an acute heart failure syndrome that typically occurs after a period of great emotional stress. The archetypal patient is a postmenopausal woman who presents with chest pain, ST-segment elevation and acute hypokinesia of the apical and middle segment of the left ventricle that extends beyond the territory of a single coronary artery, coupled with hyperkinesia of the basal myocardium. Recent preclinical and clinical studies have shown the importance of high catecholamine levels in precipitating TTS. We propose that this is caused by activation of β-adrenoceptors and the subsequent activation of a negatively-inotropic pathway, perhaps to protect the heart from catecholamine overload. We explore the pathophysiology of TTS according to its "phases", both preclinically and clinically. This will show that the condition is not one of static apical hypokinesia that simply improves, but rather a dynamic condition that changes as the disease progresses. We hope that further exploration of TTS using its "phases" will aid in its characterization, diagnosis and treatment.

Stress cardiomyopathy: yet another type of neurocardiogenic injury: 'stress cardiomyopathy'

Tako-tsubo syndrome pertains to rare acquired cardiomyopathies, characterized by left ventricular dyskinesia and symptomatology typical for acute myocardial infarction (AMI). Despite its low incidence and relatively benign course, stress cardiomyopathy should be thoroughly differentiated from AMI. The importance of tako-tsubo consists of the fact that its manifestation initially resembles AMI. Despite seemingly low incidence of tako-tsubo, acute coronary syndromes globally constitute a major epidemiological issue and both clinical entities should be accurately differentiated. Many patients present with only mild troponin release, certain extent of regional wall motion abnormalities (RWMA) and absence of hemodynamically significant coronary artery stenosis. In such instances, a careful interview aimed at preceding emotional or physical traumatic event should be undertaken. The subsequent verification of the diagnosis is based upon prompt recovery of contractile function. Although precise diagnostic criteria were formulated, symptomatology of tako-tsubo might be clinically misleading due to the possibility of concomitant coronary vasospasm, atypical pattern of RWMA and presence of non-significant coronary disease. For this reason, its exact rate might be underestimated. Stress cardiomyopathy reflects merely a single aspect of a much wider range of neurocardiogenic injury, which encompasses cardiac dysfunction associated with subarachnoid hemorrhage, intracranial hypertension and cerebral ischemia. Both psychological and physical insult to central nervous system may trigger a disastrous response of sympathetic nervous system, eventually leading to end-organ catecholamine-mediated damage. This review sought to delineate the phenomenon of tako-tsubo cardiomyopathy and deliver evidence for common pathophysiology of the broad spectrum of neurocardiogenic injury.

Mechanisms of stress (takotsubo) cardiomyopathy

Stress cardiomyopathy is a form of reversible systolic dysfunction of the mid and apical left ventricle with pathologic changes of the electrocardiogram in the absence of an obstructive coronary artery disease. The prevalence of stress cardiomyopathy among patients with symptoms suggestive of myocardial infarction is 0.7% to 2.5%, and it is found predominantly in postmenopausal women (90%). No large studies have confirmed the cause of stress cardiomyopathy. Published data suggest that substantially elevated plasma catecholamine levels, due to emotional or physical stress, may be relevant.

Reversible T-wave inversions and neurogenic myocardial stunning in a patient with recurrent stress-induced cardiomyopathy

A 72-year-old female was diagnosed as a stress-induced cardiomyopathy from apical ballooning pattern of left ventricular dysfunction without coronary artery stenosis after the mental stress. ECG showed the transient T-wave inversions after the ST-segment elevations. By the mental stress after 1 year, she showed a transient dysfunction with similar ECG changes again. T-wave inversions recovered earlier, and cardiac sympathetic dysfunction showed a lighter response corresponding to the less severe dysfunction than those after the first onset. Wellens' ECG pattern was associated with the degree of neurogenic myocardial stunning with sympathetic hyperinnervation caused by mental stress.

Interpretation of acute myocardial infarction with persistent 'hyperacute T waves' by cardiac magnetic resonance

Peaked and tall T waves represent a hyperacute electrocardiogram (ECG) manifestation of coronary artery occlusion which usually evolves into ST-segment elevation. We sought to investigate using cardiac magnetic resonance (CMR) the myocardial tissue changes underlying an atypical ECG pattern of presentation of left anterior descending artery (LAD) occlusion consisting of persistent hyperacute T waves and mild ST-segment depression. This ECG pattern is often associated with the presence of collateral circulation, which may modulate myocyte action potential changes in response to ischemia and prevent the appearance of ST-segment elevation. However, CMR findings resembled those of typical anterior myocardial infarction with nearly transmural necrosis in the large myocardial area supplied by LAD. Accordingly, persistent hyperacute T waves should be regarded as an equivalent to ST-segment elevation and immediate reperfusion therapy should be considered.

ST-segment deviation pattern of takotsubo cardiomyopathy similar to acute pericarditis: diffuse ST-segment elevation

BACKGROUND

Possible similarities or differences in the ST- and PR-segment deviations in the electrocardiogram of takotsubo cardiomyopathy (TTC) and acute pericarditis (AP) are not well defined.

METHODS

We compared different parameters of the admission electrocardiogram in eight patients with TTC and eight patients with AP with ST-segment elevation in the acute phase.

RESULTS

We found significant differences in the maximal magnitude of the T wave in the precordial leads, but not in the ST- and PR-segment deviation patterns between the two patient groups. All the patients in the two groups showed consistent ST-segment depression in lead aVR and absence of ST-segment elevation in lead V1.

CONCLUSIONS

The ST- and PR-segment deviation patterns in TTC are similar to that of AP, namely diffuse ST-segment elevations with reciprocal changes in aVR and V1 and PR-segment elevation in aVR accompanied by PR-segment depression in the inferior leads, possibly indicating that TTC has ECG characteristics of circumferential subepicardial ischemia in the acute phase.

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.

Myocardial edema underlies dynamic T-wave inversion (Wellens' ECG pattern) in patients with reversible left ventricular dysfunction

BACKGROUND

The Wellens' electrocardiogram (ECG) pattern of dynamic T-wave inversion in the anterior leads is observed in clinical conditions characterized by reversible left ventricular (LV) dysfunction (stunned myocardium), either ischemic or nonischemic. The pathophysiologic basis of this ECG pattern remains to be elucidated.

OBJECTIVE

The purpose of this study was to report the contrast-enhanced cardiac magnetic resonance (CE-CMR) findings in 4 cases of Wellens' ECG pattern associated with transient LV dysfunction from a variety of clinical conditions such as myocardial bridge, coronary artery dissection, cholecystitis, and takotsubo syndrome.

METHODS

All patients underwent CE-CMR at the time of acute clinical manifestations and after 6 to 8 weeks of follow-up to assess the presence and dynamics of LV myocardial changes.

RESULTS

In all patients, the Wellens' ECG abnormalities were associated with increased signal intensity of the LV myocardium on T2-weighted sequences suggesting myocardial edema, in the absence of late enhancement on postcontrast sequences. Repolarization abnormalities and myocardial edema had a parallel time course with persistence beyond recovery of mechanical abnormalities. T-wave inversion was associated with transient prolongation of the QTc interval in all cases.

CONCLUSION

The study results suggest that myocardial edema rather than systolic dysfunction underlies the Wellens' ECG pattern, regardless of the causative mechanism.