[Show abstract][Hide abstract] ABSTRACT: Multiple endocrine neoplasia 2 (MEN 2) is a hereditary syndrome associated with medullary thyroid carcinoma, pheochromocytoma (PCC), and hyperparathyroidism. PCCs in patients with MEN 2 are usually found in the adrenals after the manifestation of medullary thyroid cancer and are commonly bilateral and hormonally active. Unfortunately, a diagnosis of MEN 2 or PCC often is delayed until after the patient has developed an advanced MEN 2-related tumor. We present unusual electrocardiographic changes on exercise testing in MEN 2 syndrome. Transient peaked T waves and shortening QT during exercise stress testing may provide an early clue for undiagnosed PCC.<Learning objective: Stress testing is not just for the diagnosis of ischemia but it may be used to evaluate patients with symptoms that suggest exercise-induced arrhythmias. The pheochromacytoma is a disorder characterized by excess of catecholamines and is usually difficult to diagnose. Excessive sympathetic stimulation is toxic to myocytes and this toxicity may reveal itself as ECG changes such as peaked T waves and shortening of QT interval. Such changes on ECG during sympathetic stimulation such as exercise testing should raise the suspicion of pheochromacytoma.
[Show abstract][Hide abstract] ABSTRACT: Obesity has reached global pandemic that threatens the health of millions of people and is associated with numerous morbidities such as hypertension, type II diabetes mellitus, dyslipidemia, cor pulmonale, gallbladder disease, obstructive sleep apnea (OSA), certain cancers, osteoarthritis, increased surgical risk and postoperative complications, lower extremity venous and/or lymphatic problems, pulmonary embolism, stroke/cerebrovascular diseases and coronary arterial disease. Despite all these adverse associations, numerous studies and meta-analyses have documented an "obesity paradox" in which overweight and obese population with established cardiovascular disease have a better prognosis than do their lean counterparts. There are potential and plausible explanations offered by literature for these puzzling data; however, it still remains uncertain whether this phenomenon is attributable to a real protective effect of high body fat mass. In recent years, the survival advantage of patients with OSA, combined with the potential cardioprotective effects of chronic intermittent hypoxia, raise the possibility that apneas during sleep may activate preconditioning-like cardioprotective effect. Chronic intermittent hypoxia, one of the physiological markers of OSA, is characterized by transient periods of oxygen desaturation followed by reoxygenation, and is a major cause of its systemic harmful (oxidative stress, inflammation, sympathetic activity, vasculature remodelling and endothelial dysfunction) and/or protective (preconditioning-like cardioprotective) effects. Since many OSA subjects are obese, and obesity is an independent risk factor for many comorbidities associated with OSA; and also most OSA has never been diagnosed in obese patients, we hypothesed that the chronic intermittent hypoxia caused by OSA in obese patients may be one of the underlying mechanisms in morbi-mortality paradox of obesity.
Full-text · Article · Jan 2011 · Medical Hypotheses