Short-term studies indicate that administering drugs to slow ventricular response during AF in symptomatic patients yields benefits. The usual maximum dose is a total of 360 mg daily divided over four times a day.

These patients usually have significantly less physician office visits and hospitalizations. It can then be increased by 50 mcg/kg/min every 30 minutes to a max dose of 200 mcg/kg/min. However, the dose is usually not more than 450 mg per day. The role of clonidine in slowing the ventricular rate in AF is thought to be due to its central sympatholytic activity. For example, carvedilol is a less potent beta-adrenergic blocking agent compared with metoprolol. Y�x���釾�y���������O���ś��油xشww����jS_�o��w�?����qs�]�ǿ����mU��/{��is)/��͈�a��۫����|�=�!��b{��i�7������;5H��{�� �ã��V�qn�V�e{�_ݫo�����#tٛq�O/jb�h��A��A{��5��˭�g���O`�������o9�$�����i�zj��0��JY4�,����^�W�v����|��(,��e1�c7�}�m7�]�s�,? Digoxin is often added to beta-blockers or calcium channel blockers to avoid using high doses of either of the latter two agents. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule.

All these agents act by slowing AV nodal conduction and prolonging AV nodal refractoriness. Storage Therefore one can conclude from these trials that ventricular rate control of AF is an effective and acceptable treatment approach for some patients with AF. Adverse effects of beta-blockers can be seen at standard doses or as a result of toxicity. In a post hoc analysis of long-term rate control in the AFFIRM trial, patients initially treated with a beta-blocker were significantly less likely than those treated with calcium channel blockers to have their drug regimen changed. endobj Ozcan, C, Jahangir, A, Friedman, PA. “Long-term survival after ablation of the atrioventricular node and implantation of a permanent pacemaker in patients with atrial fibrillation”. The use of beta-blockers for AF rate control carries an added benefit in patients with other cardiovascular diseases, such as coronary artery disease, and diastolic and systolic heart failure. Dronedarone’s rate-controlling properties may be of benefit in patients with nonpermanent (paroxysmal or persistent) AF and associated cardiovascular risk factors. Dronedarone: Dronedarone is a multichannel blocking, antiarrhythmic agent developed as an analogue of amiodarone that inhibits sodium, potassium, and calcium channels and has antiadrenergic activity. Furthermore no standard method for assessment of heart rate control has been established to guide management of patients with AF. Amiodarone: Intravenous amiodarone may be an effective short-term agent for ventricular rate in acutely ill or postoperative patients. Metoprolol succinate, atenolol, bisoprolol, and nadolol have the advantages of longer half-lives and a single daily dosing, as well as affordability. For a less aggressive approach, infuse at 50 mcg/kg/min without a bolus being used. Farshi, R, Kistner, D, Sarma, JS. Patient symptoms and quality of life are improved in patients who undergo AV nodal ablation and permanent pacemaker implantation when adequate rate control could not be achieved with drug therapy. All rights reserved. However, in patients with exertional symptoms and persistent or permanent AF, the heart rate during exercise also should be assessed. Intravenous amiodarone may be an effective short-term option for ventricular rate in critically ill or pos-operative patients.
Beta-blockers also may reduce the incidence of AF recurrence caused by surges in sympathetic tone, such as during exercise or perioperative states. Thus one cannot conclude from these data that resting heart rates >100 bpm in AF are acceptable.

There are three important reasons to control the ventricular rate in patients presenting with atrial fibrillation (AF). Depending on associated risk factors for thromboembolism, chronic anticoagulation therapy should be administered to reduce the risk of stroke regardless of the chosen goal of AF therapy, whether rhythm control or rate control, or the specific AF therapies (pharmacologic or nonpharmacologic). Some refractory cases may necessitate the use of a beta-blocker and calcium channel blocker together with or without digoxin. Plasma digoxin levels should be monitored periodically to avoid digoxin toxicity in high-risk individuals. The ACC/AHA/HRS guidelines recommend that intravenous amiodarone be used for heart rate control in patients with AF and heart failure who do not have an accessory pathway (class I indication), and also suggest that intravenous amiodarone can be useful to control the heart rate in patients with AF when other measures are unsuccessful or contraindicated (class IIa indication). }�)s�h&�����q ��F�o�RP �V���ư@�ck�~�7B�\O�ÏϼX�G�rI������Nq���Ei-jjaω�v�� ���ͨmՏ7Wh���� f{�ŞV�=�pՌe���uj��eS�(�����ě{%t�ߟ ���X��o�6�����,��>�c Rate control allows persistence of AF and the use of drugs that slow conduction through the AV node.

This, however, must be done with caution and only in patients without heart failure symptoms or hypotension. When approaching a patient with AF and a rapid ventricular response, one must consider the urgency of therapy, as well as whether acute rate control or rhythm control would be more appropriate. Due to of the risk of toxicity and long-term side effects, amiodarone is used for chronic rate control only in refractory cases when other therapies are contraindicated or fail to result in adequate rate control. The bolus of 500 mcg/kg can be repeated up to two more times before every increase in infusion rate. That amount typically is the starting dose for hypertension treatment, too. If you miss a dose of this medicine, take it as soon as possible. When rates are not adequately controlled on a beta-blocker plus digoxin or calcium channel blocker plus digoxin, a third rate-control agent (a beta-blocker in those receiving a calcium channel blocker and vice versa) can be added. Small studies have shown some benefit in rate control with IV magnesium sulfate (2.5 g over 20 minutes followed by 2.5 g over 2 hours) when compared with a placebo.