digoxin and Embolism

Atrial fibrillation (AF), the most common form of sustained arrhythmia, is associated with a frightening risk of embolic complications, tachycardia-related ventricular dysfunction, and often disabling symptoms. Pharmacologic therapy is the treatment used most commonly to restore and maintain sinus rhythm, to prevent recurrences, or to control ventricular response rate.. This article reviews published data on pharmacologic treatment and discusses alternative systems to classify AF and to choose appropriate pharmacologic therapy.. AF is either paroxysmal or chronic. Attacks of paroxysmal AF can differ in duration, frequency, and functional tolerance. In the new classification system described, 3 clinical aspects of paroxysmal AF are distinguished on the basis of their implications for therapy. Chronic AF usually occurs in association with clinical conditions that cause atrial distention. The risk of chronic AF is significantly increased by the presence of congestive heart failure or rheumatic heart disease. Mortality rate is greater among patients with chronic AF regardless of the presence of coexisting cardiac disease. The various options available for the treatment of chronic AF include restoration of sinus rhythm or control of ventricular rate. Cardioversion may be accomplished with pharmacologic or electrical treatment. For patients in whom cardioversion is not indicated or who have not responded to this therapy, antiarrhythmic agents used to control ventricular response rate include nondihydropyridine calcium antagonists, digoxin, or beta-blockers. For patients who are successfully cardioverted, sodium channel blockers or potassium channel blockers such as sotalol, amiodarone, or a pure class III agent such as dofetilide, a selective potassium channel blocker, may be used to prevent recurrent AF to maintain normal sinus rhythm.. The ultimate choice of the antiarrhythmic drug will depend on the presence or absence of structural heart disease. An additional concern with chronic AF is the risk of arterial embolization resulting from atrial stasis and the formation of thrombi. In patients with chronic AF the risk of embolic stroke is increased 6-fold. Therefore anticoagulant therapy should be considered in patients at high risk for embolization. Selection of the appropriate treatment should be based on the concepts recently developed by the Sicilian Gambit Group (based on the specific channels blocked by the antiarrhythmic agent) and on clinical experience gained over the years with antiarrhythmic agents. For example, termination of AF is best accomplished with either a sodium channel blocker (class I agent) or a potassium channel blocker (class III agent). In contrast, ventricular response rate is readily controlled by a beta-blocker (propranolol) or a calcium channel blocker (verapamil). Alternatively, antiarrhythmic drug therapy may be chosen based on the Vaughan-Williams classification, which identifies the cellular electrophysiologic effects of the drug.

Topics: Adrenergic beta-Antagonists; Anti-Arrhythmia Agents; Atrial Fibrillation; Calcium Channel Blockers; Chronic Disease; Digoxin; Dihydropyridines; Drug Administration Routes; Electrocardiography; Embolism; Heart Rate; Humans; Practice Guidelines as Topic; Prognosis; Propranolol; Secondary Prevention; Tachycardia, Paroxysmal; Verapamil

Because of its prevalence in the population and its associated underlying diseases and morbidity, atrial fibrillation (AF) is an important and costly health problem. Advancing age, diabetes, heart failure, valvular disease, hypertension, and myocardial infarction predict the occurrence of AF within a population. The management of AF is complex and involves prevention of thromboembolic complications and treatment of arrhythmia-related symptoms. Stroke occurs in 4.5% of untreated patients with AF per year. Independent risk factors for stroke in nonrheumatic patients with AF are advanced age; a history of prior embolism, hypertension, or diabetes; and echocardiographic findings of left atrial enlargement and left ventricular dysfunction. Warfarin decreases stroke by two-thirds and death by one-third; aspirin is only about half as effective overall and is insufficient therapy for those with risk factors for stroke. Options for thromboembolic prophylaxis are use of warfarin for all in whom it is safe or, alternatively, warfarin for those with risk factors and aspirin for those without risk factors. One-half of the patients with AF are 75 years of age or older. The uniform applicability and relative safety of warfarin therapy in this age-group are controversial. Specific therapy for the arrhythmia should be dictated by the need to control symptoms. Symptomatic treatments include rate-control medications and strategies designed to terminate and prevent arrhythmia recurrence. Digoxin, beta-adrenergic blockers, verapamil, and diltiazem slow excessive ventricular rates in patients with AF and may favorably manage comorbid conditions. The efficacy of anti-arrhythmic medications is only 40 to 70% per year in preventing recurrences of AF, and these agents, except amiodarone, may increase the risk of sudden death in patients with certain types of organic heart disease and AF. The use of nonpharmacologic symptomatic therapies such as atrioventricular node modification or ablation with a rate-response pacemaker or surgical intervention is increasing.

Topics: Adrenergic beta-Antagonists; Adult; Age Factors; Aged; Anti-Arrhythmia Agents; Aspirin; Atrial Fibrillation; Catheter Ablation; Cerebrovascular Disorders; Diabetes Complications; Digoxin; Diltiazem; Embolism; Humans; Hypertension; Thromboembolism; Verapamil; Warfarin

Topics: Acrylates; Blood Urea Nitrogen; Charcoal; Creatinine; Digoxin; Embolism; Female; Gels; Hemoperfusion; Humans; Middle Aged; Poisoning; Renal Dialysis; Uremia; Uric Acid; Water-Electrolyte Balance

The authors report on a 47-years old woman with bacterial endocarditis involving both the mitral and aortic valves. At first echocardiographic examination, the mitral vegetation was small, while the aortic one was large highly mobile. Despite adequate antibiotic therapy, the aortic vegetation had become bigger and the valve regurgitation, initially mild to moderate, resulted severe and was associated with left heart failure. While awaiting surgery, the patient sustained an acute non Q wave myocardial infarction with ST segment elevation in inferior and anterolateral leads, complicated by ventricular arrhythmias. Thirty-six hours later, the patient received mitral and aortic valve replacement: at surgical view, the aortic vegetations was found to be very close to the right coronary orifice. After a period of further antibiotic therapy, the woman discharged and at a six months follow-up, she was fairly well. The authors review the mechanisms of acute coronary insufficiency in infective endocarditis and suggest an embolic pathogenesis in the case reported. Taking into account the possible life threatening embolic complications, it seems reasonable not to delay surgery when antibiotic therapy fails to reduce the size and mobility of valve vegetations.

Topics: Aortic Valve; Aortic Valve Insufficiency; Cardiotonic Agents; Digoxin; Diuretics; Echocardiography, Doppler, Color; Echocardiography, Transesophageal; Electrocardiography; Embolism; Endocarditis, Bacterial; Female; Follow-Up Studies; Furosemide; Heart Valve Prosthesis; Humans; Middle Aged; Mitral Valve; Mitral Valve Insufficiency; Myocardial Infarction; Penicillin G; Penicillins; Streptococcal Infections; Time Factors

Topics: Amphotericin B; Atrial Fibrillation; Candidiasis; Digoxin; Embolism; Endocarditis; Female; Flucytosine; Heart Valve Prosthesis; Humans; Middle Aged; Mitral Valve; Warfarin

Topics: Cardiac Surgical Procedures; Digoxin; Drug Therapy; Electrocardiography; Embolism; Heart Diseases; Humans; Mitral Valve Stenosis; Penicillins; Radiography, Thoracic; Rheumatic Heart Disease; Thoracic Surgery; Thrombosis; Vectorcardiography