Atrial fibrillation for

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. 

Digitalis is the drug of choice in atrial fibrillation for controlling ventricular rate. Its effect is due to the prolongation of the refractory period of the conducting tissue. The dose in so adjusted as to maintain the ventricular rate of 60 to 80 beats per minute at rest and approximately 100 beats per minute during light exercise. 

A 44-year-old man with no significant cardiac history was given clozapine and 12 days later had bibasal crackles in the chest and ST segment elevation in leads V2 and V3 of the electrocardiogram. He then developed ventricular tachycardia and needed resuscitation. He also developed atrial fibrillation for 24 hours, which subsequently resolved. 

Gage BF, van Walraven C, Pearce LA et al. (2004). Selecting patients with atrial fibrillation for anticoagulation. Stroke risk stratification in patients taking aspirin. Circulation 110 2287-2292 Giles MF, Rothwell PM (2007). Risk of stroke early after transient ischaemic attack a systematic review and meta-analysis. Lancet Neurology 6 1063-1072... 

A 56-year-old man was given adenosine 12 mg for a narrow-complex tachycardia on four occasions, and on each occasion developed transient atrial fibrillation for a few minutes thereafter. He had a concealed left-sided accessory pathway, which was successfully ablated (23). 

The use of oral amiodarone in preventing recurrence of atrial fibrillation, for preventing recurrence after cardioversion or for pharmacological cardioversion of atrial fibrillation, has been reviewed (18). There is insufficient evidence to support its use as a first-line drug for... 

In 208 patients with atrial fibrillation of various duration, including 50 with chronic atrial fibrillation, randomized to amiodarone or placebo, 80% converted to sinus rhythm after amiodarone compared with 40% of those given placebo (20). Amiodarone was given as an intravenous loading dose of 300 mg for 1 hour and 20 mg/kg for 24 hours, followed by 600 mg/day orally for 1 week and 400 mg/day for 3 weeks. Those who converted to sinus rhythm had had atrial fibrillation for a shorter duration and had smaller atria than those who did not convert. The shorter the duration of fibrillation and the smaller the atria the sooner conversion occurred. There was significant hypotension in 12 of the 118 patients who received amiodarone during the first hour of intravenous administration, but in all cases this responded to intravenous fluids alone. There was phlebitis at the site of infusion in... 

A 63-year-old woman with a non-ischemic dilated cardiomyopathy possibly caused by alcohol had paroxysmal atrial fibrillation for which she took sotalol 80 mg bd. She took oseltamivir 75 mg bd for presumed influenza and after 4 days developed ventricular fibrillation. Sinus rhythm was restored with multiple shocks and intravenous magnesium. The serum potassium was normal at 4.1 mmol/1. Electrocardiography showed a QT, interval of 521 ms. The QT interval gradually shortened after withdrawal of both sotalol and oseltamivir. 

Cardiovascular A 56-year-old man with hypertension had a 62% total body surface area burn and developed atrial fibrillation, for which he was given digoxin [IT ]. Pyloroplasty for a bleeding ulcer led to postoperative ileus for which intravenous metoclopramide 20 mg was given every 6 hours. Beginning on day 54, he had seven episodes of bradycardia and 15 episodes of asystole over 48 hours. Some episodes required atropine, while others resolved spontaneously. Some attacks converted initially to a junctional rhythm, and all ultimately reverted to sinus tachycardia. Serial electrocardiograms were normal. Digoxin and metoclopramide were withdrawn and several hours later the brady-dysrhythmias resolved. Metoclopramide... 

After taking rimonabant for 3 weeks a man developed dizziness, palpitation, and exertional dyspnea. He had atrial fibrillation, for which no other causes were found. Rimonabant was withdrawn and 10 days later the rhythm had reverted to sinus rhythm with first-degree atrioventricular block. 

Delirium occurred in a 69-year-old woman who had been taking paroxetine regularly for 5 years after she took flecainide for atrial fibrillation for 2 weeks her serum flecainide concentration was markedly raised and the delirium resolved 3 days after flecainide withdrawal... 

QuinidJne. Quinidine, an alkaloid obtained from cinchona bark (Sinchona sp.), is the dextrorotatory stereoisomer of quinine [130-95-0] (see Alkaloids). The first use of quinidine for the treatment of atrial fibrillation was reported in 1918 (12). The sulfate, gluconate, and polygalacturonate salts are used in clinical practice. The dmg is given mainly by the oral (po) route, rarely by the intravenous (iv) route of adniinistration. It is the most frequentiy prescribed po antiarrhythmic agent in the United States. The clinical uses of quinidine include suppression of atrial and ventricular extrasystoles and serious ventricular arrhythmias (1 3). 

Dlgltoxin. Digitoxin is a cardiac glycoside obtained from Digitalis purpurea. Digitoxin is indicated in the treatment of atrial flutter, atrial fibrillation, and supraventricular tachycardia. Its electrophysiologic and adverse effects are similar to those described for digoxin (87). 

Verapamil. Verapamil hydrochloride (see Table 1) is a synthetic papaverine [58-74-2] C2qH2 N04, derivative that was originally studied as a smooth muscle relaxant. It was later found to have properties of a new class of dmgs that inhibited transmembrane calcium movements. It is a (+),(—) racemic mixture. The (+)-isomer has local anesthetic properties and may exert effects on the fast sodium channel and slow phase 0 depolarization of the action potential. The (—)-isomer affects the slow calcium channel. Verapamil is an effective antiarrhythmic agent for supraventricular AV nodal reentrant arrhythmias (V1-2) and for controlling the ventricular response to atrial fibrillation (1,2,71—73). 

Newly developed class III drugs comprise dofetilide, a specific Ik, blocker, and ibutilide, which blocks IKl and activates the slow iNa- Both drugs lack hemodynamic side effects. These drugs are scheduled for the treatment of atrial fibrillation and atrial flutter. As with class HI drugs, they can induce torsade de pointes arrhythmia. 

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... 

Kvl.5 In human atria, the Kvl.5 presents the ultrarapid delayed rectifier that contributes to the repolarization in the early phase of cardiac action potential. Selective blockers of Kvl.5 channels could be potentially beneficial in the treatment of atrial fibrillation because blocking Kvl. 5 could delay repolarization and prolong refractoriness selectively in cardiac myocytes. Examples for Kvl.5 blockers include AVE0118, S9947, and analogs of diphenyl phosphine oxide (DPO). 

The cardiotonics are used to treat HF and atrial fibrillation. Atrial fibrillation is a cardiac arrhythmia characterized by rapid contractions of the atrial myocardium, resulting in an irregular and often rapid ventricular rate. See Chapter 40 for more information on various arrhythmias and treatment. 

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... 

Expert opinion is a source, frequently elicited by survey, that is used to obtain information where no or few data are available. For example, in our experience with a multicountry evaluation of health care resource utilization in atrial fibrillation, very few country-specific published data were available on this subject. Thus the decision-analytic model was supplemented with data from a physician expert panel survey to determine initial management approach (rate control vs. cardioversion) first-, second-, and third-line agents doses and durations of therapy type and frequency of studies that would be performed to initiate and monitor therapy type and frequency of adverse events, by body system and the resources used to manage them place of treatment and adverse consequences of lack of atrial fibrillation control and cost of these consequences, for example, stroke, congestive heart failure. This method may also be used in testing the robustness of the analysis [30]. 

The Heparin in Acute Embolic Stroke Trial (HAEST) was a multicenter, randomized trial of the effect of LMWH (dalteparin 100 lU/kg sc twice daily) or aspirin (160 mg once daily) for the acute treatment of 449 patients with ischemic stroke and atrial fibrillation (AF). The primary outcome was the rate of recurrent stroke within 14 days. No difference in rates of early recurrence (8.5% dalteparin treated vs. 7.5% aspirin treated) or good 3-month functional outcome was found. The frequency of early slCH was 2.7% on dalteparin versus 1.8% on aspirin. 

Risk factors for stroke and efficacy of antithrombotic therapy in atrial fibrillation. Analysis of pooled data from five randomized controlled trials. Arch Intern Med 1994 154 1449-1457. 

Current recommendations are for the addition of digoxin for patients who remain symptomatic despite an optimal HF regimen consisting of an ACE inhibitor or ARB, (3 -blocker, and diuretic. In patients with concomitant atrial fibrillation, digoxin may be added to slow ventricular rate regardless of HF symptomology. 

Compare and contrast the risk factors for and the features, mechanisms, etiologies, symptoms, and goals of therapy of (1) sinus bradycardia (2) atrioventricular (AV) nodal blockade (3) atrial fibrillation (AF) (4) paroxysmal supraventricular tachycardia (PSVT) ... 

Abnormal initiation of electrical impulses occurs as a result of abnormal automaticity. If the automaticity of the SA node increases, this results in an increased rate of generation of impulses and a rapid heart rate (sinus tachycardia). If other cardiac fibers become abnormally automatic, such that the rate of initiation of spontaneous impulses exceeds that of the SA node, other types of tachyarrhythmias may occur. Many cardiac fibers possess the capability for automaticity, including the atrial tissue, the AV node, the Purkinje fibers, and the ventricular tissue. In addition, fibers with the capability of initiating and conducting electrical impulses are present in the pulmonary veins. Abnormal atrial automaticity may result in premature atrial contractions or may precipitate atrial tachycardia or atrial fibrillation (AF) abnormal AV nodal automaticity may result in junctional tachycardia (the AV node is also sometimes referred to as the AV junction). Abnormal automaticity in the ventricles may result in ventricular premature depolarizations (VPDs) or may precipitate ventricular tachycardia (VT) or ventricular fibrillation (VF). In addition, abnormal automaticity originating from the pulmonary veins is a precipitant of AF. 

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice. It is important for clinicians to understand AF, because it is associated with substantial morbidity and mortality and because many strategies for drug therapy are available. Drugs used to treat AF often have a narrow therapeutic index and a broad adverse effect profile. 

TABLE 6-5. Drugs for Ventricular Rate Control in Atrial Fibrillation... 

FIGURE 6-5. Decision algorithm for ventricular rate control using intravenous drug therapy for patients presenting with the first detected episode or an episode of persistent atrial fibrillation that is hemody-namically stable. 

FIGURE 6-6. Decision algorithm for long-term ventricular rate control with oral drug therapy for patients with paroxysmal or permanent atrial fibrillation, bpm, beats per minute CCB, calcium channel blocker (diltiazem or verapamil) HF, heart failure LV, left ventricular function LVEF, left ventricular ejection fraction. (Algorithm adapted with permission from Tisdale JE, Moser LR. Tachyarrhythmias. In Mueller BA, Bertch KE, Dunsworth TS, et al. (eds.) Pharmacotherapy Self-Assessment Program, 4th ed. Kansas City American College of Clinical Pharmacy 2001 ... 

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