Kevin A. Bybee

Bio: Kevin A. Bybee is an academic researcher from University of Missouri–Kansas City. The author has contributed to research in topics: Heart failure & Coronary artery disease. The author has an hindex of 23, co-authored 46 publications receiving 4658 citations. Previous affiliations of Kevin A. Bybee include University of Rochester & Mayo Clinic.

Systematic Review: Transient Left Ventricular Apical Ballooning: A Syndrome That Mimics ST-Segment Elevation Myocardial Infarction

Abstract: The transient left ventricular apical ballooning syndrome, also known as takotsubo cardiomyopathy, is characterized by transient wall-motion abnormalities involving the left ventricular apex and mid-ventricle in the absence of obstructive epicardial coronary disease. In this paper, we review case series that report on patients with the transient left ventricular apical ballooning syndrome to better characterize patients presenting with the syndrome. We identified 7 case series that reported on at least 5 consecutive patients with the transient left ventricular apical ballooning syndrome. The syndrome more often affects postmenopausal women (82% to 100%) (mean age, 62 to 75 years). Patients commonly present with ST-segment elevation in the precordial leads, chest pain, relatively minor elevation of cardiac enzyme and biomarker levels, and transient apical systolic left ventricular dysfunction despite the absence of obstructive epicardial coronary disease. An episode of emotional or physiologic stress frequently precedes presentation with the syndrome. The in-hospital mortality rate seems to be low, as does the risk for recurrence.

Clinical characteristics and Thrombolysis In Myocardial Infarction frame counts in women with transient left ventricular apical ballooning syndrome

Abstract: The characteristics of 16 women with transient left ventricular (LV) apical ballooning syndrome in a United States population are presented. Additionally, Thrombolysis In Myocardial Infarction (TIMI) frame counts were evaluated during the acute period. Patients generally presented with anterior ST-elevation acute coronary syndrome in the absence of obstructive coronary disease. All patients had LV apical wall motion abnormalities. An acute emotional or physiologic stressor preceded most cases. TIMI frame counts were abnormal in all patients and often abnormal in all 3 major coronary vessels, suggesting that the diffuse impairment of coronary microcirculatory function may play a role in the pathogenesis of the syndrome.

Stress-Related Cardiomyopathy Syndromes

Abstract: The relationship between the heart and the brain is complex and integral in the maintenance of normal cardiovascular function. Certain pathological conditions can interfere with the normal brain-heart regulatory mechanisms and result in impaired cardiovascular function. The mechanisms through which the central and autonomic nervous systems regulate the heart and the manner in which their impairment adversely affects cardiovascular function have recently been reviewed by Samuels.1 The purpose of this article is to provide an up-to-date review of the clinical presentation of the stress-related cardiomyopathy syndromes, discuss possible causal mechanisms, and highlight the similarities and differences between them.2–16 The stress-related cardiomyopathies appear similar in that they seemingly occur during times of enhanced sympathetic tone and may be precipitated in part or entirely by excessive endogenous or exogenous catecholamine stimulation of the myocardium. Although significant clinical overlap exists in those presenting with stress-associated cardiomyopathy, it is unclear whether myocardial adrenergic hyperstimulation is the only pathophysiological mechanism responsible for these syndromes (Tables 1 and 2⇓). View this table: Table 1. Precipitants of Stress Cardiomyopathy View this table: Table 2. Morphological LV Variants of Stress Cardiomyopathy In the early 1990s, Japanese authors began reporting a unique, reversible cardiomyopathy that appeared to be precipitated by acute emotional stress.2,13,16 They found that these patients were usually postmenopausal women and often developed signs and symptoms of an acute coronary syndrome (ACS) proximate to a strong emotional stressor associated with a transient apical and midventricular wall motion abnormality despite the lack of obstructive coronary artery disease (CAD) at the time of emergent coronary angiography. This syndrome was initially given the name Takotsubo cardiomyopathy (TC) and has subsequently been referred to as the apical ballooning syndrome and broken heart syndrome. It is now recognized that TC can also occur in the setting of acute medical illness and after surgery. TC …

Neurohumoral Features of Myocardial Stunning Due to Sudden Emotional Stress

Abstract: background Reversible left ventricular dysfunction precipitated by emotional stress has been reported, but the mechanism remains unknown. methods We evaluated 19 patients who presented with left ventricular dysfunction after sudden emotional stress. All patients underwent coronary angiography and serial echocardiography; five underwent endomyocardial biopsy. Plasma catecholamine levels in 13 patients with stress-related myocardial dysfunction were compared with those in 7 patients with Killip class III myocardial infarction. results The median age of patients with stress-induced cardiomyopathy was 63 years, and 95 percent were women. Clinical presentations included chest pain, pulmonary edema, and cardiogenic shock. Diffuse T-wave inversion and a prolonged QT interval occurred in most patients. Seventeen patients had mildly elevated serum troponin I levels, but only 1 of 19 had angiographic evidence of clinically significant coronary disease. Severe left ventricular dysfunction was present on admission (median ejection fraction, 0.20; interquartile range, 0.15 to 0.30) and rapidly resolved in all patients (ejection fraction at two to four weeks, 0.60; interquartile range, 0.55 to 0.65; P<0.001). Endomyocardial biopsy showed mononuclear infiltrates and contraction-band necrosis. Plasma catecholamine levels at presentation were markedly higher among patients with stressinduced cardiomyopathy than among those with Killip class III myocardial infarction (median epinephrine level, 1264 pg per milliliter [interquartile range, 916 to 1374] vs. 376 pg per milliliter [interquartile range, 275 to 476]; norepinephrine level, 2284 pg per milliliter [interquartile range, 1709 to 2910] vs. 1100 pg per milliliter [interquartile range, 914 to 1320]; and dopamine level, 111 pg per milliliter [interquartile range, 106 to 146] vs. 61 pg per milliliter [interquartile range, 46 to 77]; P<0.005 for all comparisons). conclusions Emotional stress can precipitate severe, reversible left ventricular dysfunction in patients without coronary disease. Exaggerated sympathetic stimulation is probably central to the cause of this syndrome.

Guidelines for the diagnosis and treatment of non-ST-segment elevation acute coronary syndromes

Abstract: Guidelines and Expert Consensus Documents summarize and evaluate all currently available evidence on a particular issue with the aim to assist physicians in selecting the best management strategies for a typical patient, suffering from a given condition, taking into account the impact on outcome, as well as the risk–benefit ratio of particular diagnostic or therapeutic means. Guidelines are no substitutes for textbooks. The legal implications of medical guidelines have been discussed previously. A great number of Guidelines and Expert Consensus Documents have been issued in recent years by the European Society of Cardiology (ESC) as well as by other societies and organizations. Because of the impact on clinical practice, quality criteria for development of guidelines have been established in order to make all decisions transparent to the user. The recommendations for formulating and issuing ESC Guidelines and Expert Consensus Documents can be found on the ESC website (http://www.escardio.org/knowledge/guidelines/rules). In brief, experts in the field are selected and undertake a comprehensive review of the published evidence for management and/or prevention of a given condition. A critical evaluation of diagnostic and therapeutic procedures is performed including assessment of the risk–benefit ratio. Estimates of expected health outcomes for larger societies are included, where data exist. The level of evidence and the strength of recommendation of particular treatment options are weighed and graded according to pre-defined scales, as outlined in Tables 1 and 2 . View this table: Table 1 Classes of recommendations View this table: Table 2 Levels of evidence The experts of the writing panels have provided disclosure statements of all relationships they may have which might be perceived as real or potential sources of conflicts of interest. These disclosure forms are kept on file at the European Heart House, headquarters of the ESC. Any changes in conflict of interest that arise during the writing period must be notified to the …

Clinical Features and Outcomes of Takotsubo (Stress) Cardiomyopathy

Abstract: BackgroundThe natural history, management, and outcome of takotsubo (stress) cardiomyopathy are incompletely understood. MethodsThe International Takotsubo Registry, a consortium of 26 centers in Europe and the United States, was established to investigate clinical features, prognostic predictors, and outcome of takotsubo cardiomyopathy. Patients were compared with age- and sex-matched patients who had an acute coronary syndrome. ResultsOf 1750 patients with takotsubo cardiomyopathy, 89.8% were women (mean age, 66.8 years). Emotional triggers were not as common as physical triggers (27.7% vs. 36.0%), and 28.5% of patients had no evident trigger. Among patients with takotsubo cardiomyopathy, as compared with an acute coronary syndrome, rates of neurologic or psychiatric disorders were higher (55.8% vs. 25.7%) and the mean left ventricular ejection fraction was markedly lower (40.7±11.2% vs. 51.5±12.3%) (P<0.001 for both comparisons). Rates of severe in-hospital complications including shock and death were ...