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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We report our experience with flecainide and propafenone therapy for inducible supraventricular tachycardias and paroxysmal supraventricular tachycardias due to atrioventricular (AV) nodal reentry or the Wolff-Parkinson-White syndrome. We performed an electropharmacologic test (ET) that consisted of first inducing a clinical arrhythmia by transesophageal atrial pacing (TAP) protocol. This was followed by intravenous drug administration and TAP reevaluation, either after acute intravenous administration or in oral steady-state. ⋯ In 15 patients, both flecainide and propafenone were tested, 8 receiving flecainide after a negative ET with propafenone, and 7 receiving propafenone after a negative ET with flecainide. In the first group, the ET was positive in 7 (87.5%), and in the second group, it was positive in 3 (42.9%). In a follow-up of 40.1 +/- 11 months, 38 (65.5%) patients had positive outcomes, 5 (8.6%) had to stop receiving the drugs because of side effects, 3 (5.2%) stopped because of inefficacy, and 12 (20.7%) dropped out.(ABSTRACT TRUNCATED AT 250 WORDS)