The American journal of medicine
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Long-term activation of the sympathetic nervous system exerts adverse biologic effects that are mediated through alpha(1), beta(1) and beta(2) receptors and that contribute importantly to the progression of heart failure. As a result, beta blockers are no longer considered to be contraindicated for use in these patients but instead now play a critical role in the successful management of chronic heart failure. ⋯ The database supporting the use of beta blockers is now as persuasive (and arguably more persuasive) than the database supporting the use of ACE inhibitors in heart failure (which comprises about 7,000 patients). Yet, the benefits of beta blockers are seen in patients already receiving ACE inhibitors, suggesting that combined blockade of two neurohormonal systems (renin-angiotensin system and sympathetic nervous system) can produce additive effects.
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Echocardiography is advocated by some as a useful diagnostic test for patients with suspected pulmonary embolism (PE), but its diagnostic accuracy is unknown. The present study was undertaken to determine prospectively the sensitivity and specificity of transthoracic echocardiography in the diagnosis of PE. ⋯ In unselected patients with suspected PE, transthoracic echocardiography fails to identify some 50% of patients with angiographically proven PE. Although echocardiographic findings of RV strain, paired with a high clinical likelihood, support a diagnosis of PE, the transthoracic echocardiography has to have a better sensitivity to be used as a screening test to rule out PE.