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Repolarization alternans is a harbinger of sudden cardiac death, particularly when it becomes spatially discordant. Alternans, a beat-to-beat alternation in the action potential duration (APD) and intracellular Ca (Cai), can arise from either tissue heterogeneities or dynamic factors. Distinguishing between these mechanisms in normal cardiac tissue is(More)
The etiology of rotator cuff disease is multifactorial. One theory behind the high incidence of rotator cuff tears in the shoulder is that the supraspinatus/infraspinatus tendon contains a zone of relative avascularity in the area proximal to its insertion at the greater tuberosity. Tobacco smoking is known to contribute to microvascular disease, and it can(More)
OBJECTIVES The goal of this study was to evaluate the diagnostic performance of a comprehensive, multicomponent cardiac magnetic resonance (CMR) study for assessment of left atrial (LA) and left atrial appendage (LAA) thrombus. BACKGROUND Pre-operative evaluation for pulmonary vein isolation (PVI) typically requires tomographic imaging to define pulmonary(More)
BACKGROUND Catheter ablation of ventricular tachycardia (VT) can be technically challenging due to difficulty with catheter positioning in the left ventricle (LV) and achieving stable contact. The Hansen Sensei Robotic system (HRS) has been used in atrial fibrillation but its utility in VT is unclear. OBJECTIVE The purpose of this study was to test the(More)
BACKGROUND During development, AV conduction switches from base-to-apex to apex-to-base conduction after emergence of the conduction system. We hypothesize that after this transition, the bulk of the AV ring, although no longer required for AV conduction, remains transiently able to conduct, providing a potential arrhythmia substrate. We studied AV(More)
How stable are neural activity patterns compared across periods of sleep? We evaluated this question in adult zebra finches, whose premotor neurons in the nucleus robustus arcopallialis (RA) exhibit sequences of bursts during daytime singing that are characterized by precise timing relative to song syllables. Each burst has a highly regulated pattern of(More)
BACKGROUND The presence of circadian variations in sympathetic outflow from the stellate ganglia is unclear. OBJECTIVES The purpose of this study was to continuously record stellate ganglion nerve activity (SGNA) in ambulatory dogs. METHODS We performed continuous 24-hour left (N = 3) or bilateral (N = 3) SGNA recordings in normal ambulatory dogs using(More)
T-wave alternans, an important arrhythmogenic factor, has recently been described in human fetuses. Here we sought to determine whether alternans can be induced in the embryonic mouse hearts, despite its underdeveloped sarcoplasmic reticulum (SR) and, if so, to analyze the response to pharmacological and autonomic interventions. Immunohistochemistry(More)
Differentiation of chronic pancreatitis and pancreatic carcinoma can be a clinical and radiologic dilemma. Several patients with chronic pancreatitis can undergo unnecessary major abdominal surgery for benign lesions. This pictorial review illustrates the computed tomographic findings and histopathologic features of lesions mimicking pancreatic neoplasm in(More)