The American journal of cardiology
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The renin-angiotensin system (RAS) plays a major role in the control of blood pressure and cardiovascular homeostasis and is involved in the pathogenesis of a number of cardiovascular disorders. The efficacy of angiotensin-converting enzyme (ACE) inhibitors in the treatment of hypertension and congestive heart failure has led to the widespread clinical use of ACE inhibitors in primary or secondary prevention of heart disease. ⋯ Whereas the circulating endocrine RAS appears to be responsible for mediation of acute effects, the tissue RAS seems to be involved in more chronic situations, such as secondary structural changes of the cardiovascular system, and therefore could contribute to the pathogenesis of hypertension as well as other cardiovascular disorders, such as cardiac hypertrophy, coronary artery disease, and atherosclerosis. Several experimental and clinical findings suggest that reversal of cardiovascular structural changes secondary to cardiovascular disease and enhancement of renal sodium excretion by ACE inhibitors are important long-term antihypertensive actions possibly mediated by inhibition of the tissue RAS.
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It is often difficult to predict outcome in hospitalized patients with pericardial effusion. To address this issue, the prognostic value of echocardiography was studied in 187 hospitalized patients diagnosed with pericardial effusions over a 1-year period. The index echocardiogram showed that 11 effusions were large (6%), 39 were moderate (21%), and 137 were small (73%). ⋯ By univariate analysis, each echocardiographic sign was associated with both cardiac tamponade and the combined end point (p less than or equal to 0.01 for comparisons with size and right-sided chamber collapse; p less than or equal to 0.07 for comparisons with IVC plethora). When the data were analyzed with logistic regression modeling, effusion size was the most powerful predictor of outcome (cardiac tamponade: odds ratio 51, 95% confidence interval 3.5-729, p = 0.004; combined end point: odds ratio 78, 95% confidence interval 14-421, p = 0.0001), and neither right-sided chamber collapse nor IVC plethora with blunted response to respiration retained significant associations. It is concluded that echocardiographically determined effusion size is a powerful predictor of outcome in hospitalized patients with pericardial effusion, and that right-sided chamber collapse and IVC plethora with blunted response to respiration add little if any additional prognostic information.
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Several formulas have been proposed to adjust the QT interval for heart rate, the most commonly used being the QT correction formula (QTc = QT/square root of RR) proposed in 1920 by Bazett. The QTc formula was derived from observations in only 39 young subjects. Recently, the adequacy of Bazett's formula has been questioned. ⋯ The linear regression model yielded a correction formula (for a reference RR interval of 1 second): QTLC = QT + 0.154 (1-RR) that applies for men and women. This equation corrects QT more reliably than the Bazett's formula, which overcorrects the QT interval at fast heart rates and undercorrects it at low heart rates. Lower and upper limits of normal QT values in relation to RR were generated.(ABSTRACT TRUNCATED AT 250 WORDS)
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Meta Analysis
Short- and long-term efficacy and safety of flecainide acetate for supraventricular arrhythmias.
This report summarizes efficacy and safety data on the use of flecainide acetate for supraventricular arrhythmias. For this purpose, 60 original articles were identified by a literature search representing data from 1,835 treatment courses. In 18 trials, flecainide was administered intravenously; in 19, orally; and in 23, both forms of therapy were applied. ⋯ Ectopic atrial tachycardia responded in 86% and 95% of patients treated with flecainide acutely or chronically. Data concerning drug-related side effects were available for 1,794 of 1,835 treatment courses (98%). Overall, 352 of 1,794 patients (20%) reported at least one non-cardiac or cardiac adverse experience.(ABSTRACT TRUNCATED AT 250 WORDS)