Atrial Fibrillation
Canadian pharmacy
Atrial fibrillation (AF) is the commonest cardiac arrhythmia, and it is responsible for one million hospital admissions per annum in the United States. The prevalence of atrial fibrillation (AF) increases with age. Among 18,403 civil servants in Britain AF was present in 0.2% of subjects aged 40 to 49 years and 1.1% among those aged 60-64 years. Among patients in a geriatric hospital the prevalence of AF in subjects older than 84 years was found to be 14%. Therefore, as the population continues to age physicians will increasingly will face the therapeutic challenge of atrial fibrillation.

Atrial Fibrillation and Left Ventricular Function

Although originally thought to be a “benign” arrhythmia in the Framingham Heart Study total mortality among subjects with AF was nearly twice that of subjects with out. Increasingly attention is now being focused on the potentially harmful effects of chronic atrial fibrillation on cardiac function. This phenomenon has been called tachycardia-related cardiomyopathy, and in both patients and animal models the syndrome is characterized by reduced left ventricular ejection fraction, ventricular dilatation and, frequently, reversibility of the syndrome if the tachycardia is abolished. Benefits are clearly seen with restoration of sinus rhythm. Van Gelder et al. reported eight patients with chronic atrial fibrillation who were cardioverted then successfully maintained in sinus rhythm throughout a six month follow-up period. At follow-up there was improvement in atrial contribution to left ventricular filling and in ejection fraction and exercise capacity. In cases where sinus rhythm cannot be restored, there is also evidence that palliation by rate and rhythm control provides benefit. Grogan, et al. reported a dramatic improvement in ventricular function following successful of heart rate with AV-nodal blocking drugs in patients with atrial fibrillation whose ventricular dysfunction was so severe that they were initially believed to suffer from idiopathic dilated cardiomyopathy.
Generic diamox online
Pharmacologic control of heart rate is a well established treatment, and often successful, however there are concerns about the safety of anti-arrhythmic drugs. Commonly used drugs include quinidine (Class 1A) and flecainide (Class 1C). Potential dangers of quinidine were recently highlighted by a meta-analysis of six controlled trials of quinidine versus placebo which has raised new concerns about the safety of quinidine therapy in AF patients. Although the meta-analysis found a fair level of efficacy (50% of. the quinidine group remained in sinus rhythm at one year versus 25% of the placebo group.), it also found a mortality of 2.9% among the quinidine treated patients versus 0.8% for those treated with placebo. In the case of flecainide, which is very effective in reducing attacks of paroxysmal AF, the Cardiac Arrhythmia Suppression Trial (CAST) showed that mortality was increased by the drug in patients with prior myocardial infarction.
Allergy medications
Patients with heart failure are those in whom the benefits of rate and rhythm control of atrial fibrillation could be most effective, since in this group some or all of then left ventricular dysfunction might be due to tachycardia-induced cardiomyopathy. The effect of anti-arrhythmic drugs in this group is therefore of great interest. The results of the recently published Stroke Prevention in Atrial Fibrillation Study (SPAF) provide the most compelling direct information regarding potential risks of antiarrhythmic drug therapy. For patients in AF with a history of heart failure, antiarrhythmic drugs increased the risk of cardiac death 3.3 times and the risk of arrhythmic death 5.8 times.