The American journal of cardiology
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Data from 2 decades of clinical electrophysiologic studies have allowed great progress in the evaluation and treatment of patients with sustained ventricular arrhythmias and the appropriate identification of those patients at high risk for subsequent sudden death. The goals of treatment of the patient with ventricular arrhythmias are to suppress symptoms and prevent a fatal event. ⋯ Although low-risk groups may benefit from reassurance or medications such as beta-blockers or verapamil, high-risk groups have been more difficult to treat. Recent randomized trials of implantable cardioverter defibrillators (ICDs) for ventricular arrhythmias suggest that they may provide better protection for high-risk patients than do antiarrhythmic medications.
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Although atrial fibrillation is the most common sustained arrhythmia that requires medical attention, it remains a challenge to treat. Nevertheless, considerable progress has been made toward developing curative, catheter-based treatments for selected patients with atrial fibrillation. The most significant clinical observation during electrophysiologic testing in patients with atrial fibrillation has been a recognition of the importance of the pulmonary veins for the initiation of this arrhythmia. ⋯ In addition, ablation strategies that are designed to electrically isolate the pulmonary veins from the bulk of the left atrium are likely to lead to improvements in the long-term outcome of ablation. For patients with permanent atrial fibrillation, considerable progress has been made in the restoration of sinus rhythm by linear ablation strategies in the left atrium. It is likely that a comprehensive nonpharmacologic treatment for atrial fibrillation will incorporate the lessons learned from each of these approaches and lead to a genuine cure of this vexing arrhythmia.
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Biventricular pacing has been proposed to resynchronize ventricular contraction in patients with congestive heart failure (CHF) and interventricular conduction delay. However, the sudden death rate is still high despite the improvement in cardiac performance. Devices combining biventricular pacing with implantable cardioverter defibrillator (ICD) backup are now under clinical investigation to demonstrate whether they can decrease sudden death. ⋯ Functional class improved from 2.8 +/- 0.7 to 1.6 +/- 0.5 (p <0.001) 3 months after implant. Thus, ischemic patients with reduced left ventricular ejection fraction and ventricular tachyarrhythmias seem good candidates for biventricular pacing with ICD backup. The sudden death risk for those with idiopathic dilated cardiomyopathy, however, is difficult to stratify, and the choice of ICD backup has to be considered on the basis of patient safety, as well as of costs.
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Randomized Controlled Trial Comparative Study Clinical Trial
Comparison of intravenous flecainide, propafenone, and amiodarone for conversion of acute atrial fibrillation to sinus rhythm.
In a prospective, single-blind trial, we randomized 150 consecutive symptomatic patients with acute (< or = 48 hours' duration) atrial fibrillation to receive intravenous flecainide, propafenone, or amiodarone. Flecainide and propafenone were administered as a bolus dose of 2 mg/kg in 20 minutes. A second bolus dose of 1 mg/kg in 20 minutes was administered if conversion to sinus rhythm was not achieved after 8 hours. ⋯ Median time to conversion to sinus rhythm was different among groups (p < 0.001), and it was lower in the flecainide (25 minutes; range 4 to 660) and propafenone (30 minutes; range 10 to 660) groups than in the amiodarone group (333 minutes; range 15 to 710; p < 0.001 for both comparisons). Flecainide, at the doses administered in this study, is more effective than propafenone and amiodarone for conversion of acute atrial fibrillation to sinus rhythm. Propafenone and amiodarone have similar conversion rates, although propafenone was faster in achieving the conversion to sinus rhythm.
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Comparative Study
Diabetes mellitus, impaired fasting glucose, atherosclerotic risk factors, and prevalence of coronary heart disease.
Patients with diabetes mellitus (DM), both diagnosed (history of) and undiagnosed (by fasting glucose [FG] only), as well as impaired FG have an increased risk of coronary heart disease (CHD), compared with those with normal FG. Elevations in FG levels, even in normoglycemic subjects (<110 mg/dl), may be significantly related to CHD morbidity and mortality. Improving lipid profiles and blood pressure can decrease both CHD morbidity and mortality in these patients. ⋯ Thus, patients with impaired FG, DM-FG, and history of DM should be considered at higher risk for CHD morbidity and mortality. However, hyperglycemia, per se, does not explain the excess risk. In addition to glucose, lipid profiles and blood pressure should be periodically monitored and appropriate treatment provided to reduce morbidity and mortality from CHD.