Medication Summary
The goals of pharmacotherapy are to reduce morbidity and to prevent complications.
Antiarrhythmics
Class Summary
These agents alter the electrophysiologic mechanisms responsible for arrhythmia.
Digoxin (Lanoxicaps, Lanoxin)
Cardiac glycoside with direct inotropic effects and indirect effects on the cardiovascular system. Acts directly on cardiac muscle, increasing myocardial systolic contractions. Indirect actions result in increased carotid sinus nerve activity and enhanced sympathetic withdrawal for any given increase in mean arterial pressure.
Amiodarone (Cordarone, Pacerone)
May inhibit AV conduction and sinus node function. Prolongs action potential and refractory period in myocardium and inhibits adrenergic stimulation. Prior to administration, control ventricular rate and CHF (if present) with digoxin or calcium channel blockers.
Calcium channel blockers
Class Summary
In specialized conducting and automatic cells in the heart, calcium is involved in the generation of the action potential. Calcium channel blockers inhibit movement of calcium ions across the cell membrane, depressing both impulse formation (automaticity) and conduction velocity.
Diltiazem (Cardizem CD, Dilacor, Tiazac, Cardizem LA)
During depolarization, inhibits calcium ions from entering slow channels and voltage-sensitive areas of vascular smooth muscle and myocardium.
Anticoagulants
Class Summary
These agents prevent recurrent or ongoing thromboembolic occlusion of the vertebrobasilar circulation.
Warfarin (Coumadin)
Interferes with hepatic synthesis of vitamin K–dependent coagulation factors. Used for prophylaxis and treatment of venous thrombosis, pulmonary embolism, and thromboembolic disorders. Tailor dose to maintain an INR of 2-3.
Heparin
Augments activity of antithrombin III and prevents conversion of fibrinogen to fibrin. Does not actively lyse but is able to inhibit further thrombogenesis. Prevents reaccumulation of clot after spontaneous fibrinolysis.
Beta-adrenergic blockers
Class Summary
These agents inhibit chronotropic, inotropic, and vasodilatory responses to beta-adrenergic stimulation.
Metoprolol (Lopressor, Toprol XL)
Selective beta1-adrenergic receptor blocker that decreases automaticity of contractions. During IV administration, carefully monitor blood pressure, heart rate, and ECG.
Antibiotics
Class Summary
Must cover all likely pathogens in the context of this clinical setting. Use as prophylaxis against streptococcal infections.
Penicillin G benzathine (Bicillin L-A, Permapen)
Interferes with synthesis of cell wall mucopeptides during active multiplication, which results in bactericidal activity. Used to treat syphilis and for prophylaxis of recurrent streptococcal infections.
Diuretics
Class Summary
Diuretics are used for treatment of pulmonary congestion. Treatment may improve symptoms of venous congestion through elimination of retained fluid and preload reduction.
Furosemide (Lasix)
Increases excretion of water by interfering with chloride-binding cotransport system, which, in turn, inhibits sodium and chloride reabsorption in ascending loop of Henle and distal renal tubule. Dose must be individualized to patient. Depending on response, administer at increments of 20-40 mg, no sooner than 6-8 h after previous dose, until desired diuresis occurs. When treating infants, titrate with increments of 1 mg/kg/dose until a satisfactory effect is achieved.
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Mitral Stenosis. M-mode across the mitral valve showing a flat E-F slope resulting from elevated left atrial pressure throughout diastole due to a significant gradient across the mitral valve. Increased thickness and calcification of anterior leaflet of the mitral valve and decreased opening of the anterior and posterior leaflets in diastole are also shown.
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Mitral Stenosis. Parasternal long-axis view demonstrating calcification and doming in diastole of the anterior valve leaflet and mild restriction in the opening of posterior mitral valve leaflet.
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Mitral Stenosis. Apical 4-chamber view demonstrating restricted opening of the anterior and posterior mitral valve leaflet with diastolic doming of anterior leaflet with left atrial enlargement.
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Mitral Stenosis. Transesophageal echocardiogram with continuous wave Doppler interrogation across the mitral valve demonstrating an increased mean gradient of 16 mm Hg consistent with severe mitral stenosis.
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Mitral Stenosis. Apical 4-chamber view with color Doppler demonstrating aliasing in the atrial side of the mitral valve consistent with increased gradient across the valve. This figure also shows mitral regurgitation and left atrial enlargement.
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Mitral Stenosis. Magnified view of the mitral valve in apical 4-chamber view revealing restricted opening of both leaflets.
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Mitral Stenosis. Transesophageal echocardiogram in an apical 3-chamber view showing calcification and doming of the anterior mitral leaflet and restricted opening of both leaflets.
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Mitral Stenosis. Transesophageal echocardiogram in an apical 3-chamber view with color Doppler interrogation of the mitral valve revealing aliasing, which is consistent with increased gradient across the mitral valve secondary to stenosis. Also shown in this image, a posteriorly directed jet of severe mitral regurgitation.