Atrial fibrillation prevention

Atrial Overdrive Pacing for Atrial Fibrillation Prevention... 

In summary, the lowest risk of atrial fibrillation is achieved with maintenance of both AV and interventricnlar synchrony where possible. However, the benefits appear to be relatively small and only become evident years after pacemaker implant. Mnltisite and alternate site pacing as well as pacing algorithms have not yet proven to be of significant benefit in atrial fibrillation prevention. 

Komatsu T, Ozawa M, Tachibana H, Sato Y, Orii M, Kunugida F, Nakamura M. Combination therapy with amiodarone and enalapril in patients with paroxysmal atrial fibrillation prevents the development of structural atrial remodelling. Int Heart J 2008 49(4) 435-47. 

Coumarin is also widely used for long-term anticoagulation in chronic atrial fibrillation (particularly to avoid cardioembolic strokes), to prevent DVT or PE in patients with chronic hypercoagulability (e.g., congenital AT or protein C deficiency), or to prevent... 

The uses of the antiarrhythmic drug are given in the Summaiy Drug Table Antiarrhythmic Drug3. In general these drugp are used to prevent and treat cardiac arrhythmias, such as premature ventricular contractions (PVCs), ventricular tachycardia (VT), premature atrial contractions (PACs), paroxysmal atrial tachycardia (PAT), atrial fibrillation, and atrial flutter. Some of the antiarrhythmic dru are used for other... 

Prevention and treatment of atrial fibrillation with embolization... 

Hart RG, Halperin JL, Pearce LA, Anderson DC, Kronmal RA, McBride R, Nasco E, Sherman DG, Talbert RL, Marler JR. Lessons from the stroke prevention in atrial fibrillation trials. Ann Intern Med 2003 138 831-838. 

FIGURE 6-9. Decision algorithm for stroke prevention in atrial fibrillation.27 Risk factors for stroke prior transient ischemic attack or stroke hypertension heart failure rheumatic heart valve disease prosthetic heart valve. Target International Normalized Ratio = 2.5 (range 2 to 3). 

Warfarin has been the primary oral anticoagulant used in the United States for the past 60 years. Warfarin is the anticoagulant of choice when long-term or extended anticoagulation is required. Warfarin is FDA-approved for the prevention and treatment of VTE, as well as the prevention of thromboembolic complications in patients with myocardial infarction, atrial fibrillation, and heart valve replacement. While very effective, warfarin has a narrow therapeutic index, requiring frequent dose adjustments and careful patient monitoring.15,29... 

Warfarin has not been adequately studied in non-cardioembolic stroke, but it is often recommended in patients after antiplatelet agents fail. One small retrospective study suggests that warfarin is better than aspirin.30 More recent clinical trials have not found oral anticoagulation in those patients without atrial fibrillation or carotid stenosis to be better than antiplatelet therapy. In the majority of patients without atrial fibrillation, antiplatelet therapy is recommended over warfarin. In patients with atrial fibrillation, long-term anticoagulation with warfarin is recommended and is effective in both primary and secondary prevention of stroke.12 The goal International Normalized Ratio (INR) for this indication is 2 to 3. 

The growth and spread of thyroid carcinoma is stimulated hy TSH. An important component of thyroid carcinoma management is the use ofLT4 to suppress TSH secretion. Early in therapy, patients receive the lowest LT4 dose sufficient to fully suppress TSH to undetectable levels. Controlled trials show that suppressive LT4 therapy reduces tumor growth and improves survival. These patients are purposefully overtreated with LT4 and rendered subclinically hyperthyroid. Postmenopausal women should receive aggressive osteoporosis therapy to prevent LT4-induced bone loss. Other thyrotoxic complications, such as atrial fibrillation, should be monitored and managed appropriately. 

Anticoagulant drugs include heparin and warfarin (Coumadin ) —agents used to prevent deep vein thrombosis. They are also used to prevent formation of emboli due to atrial fibrillation, valvular heart disease, and other cardiac disorders. Heparin, which is not absorbed by the gastrointestinal tract, is available only by injection its effect is immediate. 

FIGURE 6-2. Algorithm for the treatment of acute (top portion) paroxysmal supraventricular tachycardia and chronic prevention of recurrences (bottom portion). Note For empiric bridge therapy prior to radiofrequency ablation procedures, calcium channel blockers (or other atrioventricular [AV] nodal blockers) should not be used if the patient has AV reentry with an accessory pathway. (AAD, antiarrhythmic drugs AF, atrial fibrillation AP, accessory pathway AVN, atrioventricular nodal AVNRT, atrioventricular nodal reentrant tachycardia AVRT, atrioventricular reentrant tachycardia DCC, direct-current cardioversion ECG, electrocardiographic monitoring EPS, electrophysiologic studies PRN, as needed VT, ventricular tachycardia.)... 

Warfarin is the antithrombotic agent of first choice for secondary prevention in patients with atrial fibrillation and a presumed cardiac source of embolism. 

Reiffel JA. Will direct thrombin inhibitors replace warfarin for preventing embolic events in atrial fibrillation Curr Opin Cardiol 2004 19 58-63. 

Pindolol, like nadolol, is a nonselective 8-adrenoblocker. It possesses antianginal, antihypotensive, and antiarrythmic action. It is used for arterial hypertension, angina stress (preventing attacks), supraventricular tachycardia, tachsystohc form of atrial fibrillation, and superventricular extrasystole. Synonyms of this drug are carvisken, visken, and others. 

Qninidine exhibits all of the pharmacological properties of qninine, including antimalar-ial, fever-redncing, and other properties. Quinidine is used in varions forms of arrhythmia for preventing tachycardia and atrial fibrillation, and particularly for preventing ciliary fibrillation, paroxysmal snpraventricnlar tachycardia, extrasystole, and ventricular tachycardia. However, it is a toxic drug and is nsed relatively rarely. 

Verapamil is used for preventing angina pectoris attacks, arterial hypertension, and treating and preventing supraventricular arrhythmia (paroxysmal supraventricular tachycardia, atrial fibrillation, atrial flutter, extrasystole). Synonyms of this drug are isoptin, calan, fmoptin, falicard, manidone, and many others. 

Atrial fibrillation For the prevention of paroxysmal atrial fibrillation/flutter (PAF) associated with disabling symptoms and paroxysmal supraventricular tachycardias (PSVT), including atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia, and other supraventricular tachycardias of unspecified mechanism associated with disabling symptoms in patients without structural heart disease. 

The SPAF III Writing Committee for the Stroke Prevention in Atrial Fibrillation Investigators. Patients with nonvalvular atrial fibrillation at low risk of stroke dur-... 

Kondstaal P. Anticoagulants for preventing stroke in patients with nonrheumatic atrial fibrillation and a history of stroke or transient ischemic attacks. Cochrane Database Syst Rev 1999. Issue 4. 

Unlabeled Uses Control of hemodynamicallystableventriculartachycardia, control of rapid ventricular rate due to accessory pathway conduction in preexcited atrial arrhythmias, conversion of atrial fibrillation to normal sinus rhythm, in cardiac arrest with persistent ventricular tachycardia or ventricular fibrillation, paroxysmal supraventricular tachycardia, polymorphic ventricular tachycardia or wide complex tachycardia of uncertain origin, prevention of postoperative atrial fibrillation... 

Rapid loading dose for the management and treatment of CHF control ofventricular rate In patients with atrial fibrillation-, treatment and prevention of recurrent paroxysmal atrial tachycardia PO Initially, 0.5-0.75 mg, additional doses of 0.125-0.375 mg at 6-to8-hr intervals. Range 0.75-1.25 mg. IV 0.6-1 mg. 

Maintenance dosage for CHF control of ventricular rate in patients with atrial fibrillation treatment and prevention of recurrent paroxysmal atrial tachycardia PO, IV... 

Prevention of venous thrombosis, pulmonary embolism, peripheral arterial embolism, atrial fibrillation with embolism Subcutaneous 5000 units q8-12h. 

Maintenance of normal sinus rhythm after conversion of atrial fibrillation or flutter, prevention of premature atrial, AV, and ventricular contractions paroxysmal atrial tachycardia paroxysmal AV functional rhythm atrial fibrillation atrial flatter paroxysmal ventricular tachycardia not associated with complete heart block PO 100-600 mg q4-6h. (Long-acting) 324-972 mg q8-12h. IV 200-400 mg. 

Arrhythmias, including prevention of recurrent paroxysmal supraventricular tachycardia and control of ventricular resting rate in chronic atrial fibrillation or flutter (with di-goxin) PO 240-480 mg/day in 3-4 divided doses. 

It is indicated in prevention of atrial arrhythmia, atrial fibrillation or flutter, paroxysmal supraventricular tachycardia, ventricular premature beats and ventricular tachycardia. 

Low doses (100-200 mg/d) of amiodarone are effective in maintaining normal sinus rhythm in patients with atrial fibrillation. The drug is effective in the prevention of recurrent ventricular tachycardia. It is not associated with an increase in mortality in patients with coronary artery disease or heart failure. In many centers, the implanted cardioverter-defibrillator (ICD) has succeeded drug therapy as the primary treatment modality for ventricular tachycardia, but amiodarone may be used for ventricular tachycardia as adjuvant therapy to decrease the frequency of uncomfortable cardioverter-defibrillator discharges. The drug increases the pacing and defibrillation threshold and these devices require retesting after a maintenance dose has been achieved. 

Treatment of atrial fibrillation is initiated to relieve patient symptoms and prevent the complications of thromboembolism and tachycardia-induced heart failure, the result of prolonged uncontrolled heart rates. The initial treatment objective is control of the ventricular response. This is usually achieved by use of a calcium channel-blocking drug alone or in combination with a 13-adrenergic blocker. Digoxin may be of value in the presence of heart failure. A second objective is a restoration and maintenance of normal sinus rhythm. Several studies show that rate control (maintenance of ventricular rate in the range of 60-80 bpm) has a better benefit-to-risk outcome than rhythm control (conversion to normal sinus rhythm) in the long-term health of patients with atrial fibrillation. If rhythm control is deemed desirable, sinus rhythm is usually restored by DC cardioversion in the USA in... 

A major focus of drug development has been to develop orally active anticoagulants that do not require monitoring. Rivaroxiban is the first oral factor Xa inhibitor to reach phase III clinical trials. The safety and efficacy of rivaroxiban appears to be at least equivalent, and possibly superior, to LMW heparins for prevention of deep vein thrombosis no routine monitoring is required. This drug is also in clinical trials for treatment of deep vein thrombosis and prevention of stroke in atrial fibrillation. 

Kitamura, K., Shibata, R., Tsuji, Y., Shimano, M., Inden, Y., and Murohara, T. (2011). Eicosapentaenoic acid prevents atrial fibrillation associated with heart failure in a rabbit model. Am. J. Physiol. Heart Circ. Physiol. 300, H1814-H1821. 

Stroke Prevention in Atrial Fibrillation Study Group of Investigators Special Report. N. Eng J. Med., 863 (March 22, 1990). 

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