eMedicine Specialties > Emergency Medicine > Cardiovascular
Cardiomyopathy, Restrictive: Treatment & Medication
Updated: Jul 3, 2008
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
Treatment
Emergency Department Care
With the possible exception of chelation therapy for hemochromatosis and corticoidsteroid therapy for sarcoidosis, restrictive cardiomyopathy has no specific treatment. ED care is symptom directed. The mainstay of treatment options include diuretics, vasodilators, angiotensin-converting enzyme inhibitors as indicated, as well as anticoagulation (if not contraindicated).
Consultations
Cardiology consultation is suggested in order to optimize management and establish a definitive diagnosis.
Medication
As mentioned above, treatment of restrictive cardiomyopathy is symptomatic. Treatment goals include decreasing systemic and pulmonary congestion, lowering ventricular filling pressure, augmenting systolic pump function, and reducing risk for embolism.
Loop diuretics
Diuretics are used to reduce pulmonary and systemic congestion. Initiate therapy with a low dosage because relatively high levels of ventricular filling pressure must be maintained for adequate diastolic filling.
Furosemide (Lasix)
Increases excretion of water by interfering with chloride-binding cotransport system resulting from inhibition of reabsorption of sodium and chloride in ascending loop of Henle and distal renal tubule.
Adult
40-160 mg/d IV/IM
Pediatric
1 mg/kg IV/IM; increase by 1 mg/kg/dose q6-12h; not to exceed 6 mg/kg
Metformin decreases concentrations; interferes with hypoglycemic effect of antidiabetic agents and antagonizes muscle-relaxing effect of tubocurarine; concurrent aminoglycosides may increase auditory toxicity—hearing loss of varying degrees may occur; may enhance anticoagulant activity of warfarin; may increase plasma levels and toxicity of lithium
Documented hypersensitivity; hepatic coma; anuria; severe electrolyte depletion
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Measure serum electrolytes, CO2, glucose, creatinine, uric acid, calcium, and BUN frequently during first few months of therapy and periodically thereafter
Inotropic agents
Digitalis and other positive inotropic agents generally are not indicated unless systolic pump function and contractility are impaired. Digitalis must be used with caution in patients with amyloid cardiomyopathy as they may be digoxin sensitive (arrhythmogenic) because of amyloid fibril binding of digoxin.
Digoxin (Lanoxin)
Added to regimen to enhance myocardial contractility. Cardiac glycoside with direct inotropic effects in addition to indirect effects on cardiovascular system.
Adult
0.125-0.375 mg PO qd
Pediatric
<10 years: Not established
>10 years: 10-15 mcg/kg PO
Maintenance dosing: 25-35% of loading dose
Medications that may increase digoxin levels include alprazolam, benzodiazepines, bepridil, captopril, cyclosporine, propafenone, propantheline, quinidine, diltiazem, aminoglycosides, oral amiodarone, anticholinergics, diphenoxylate, erythromycin, felodipine, flecainide, hydroxychloroquine, itraconazole, nifedipine, omeprazole, quinine, ibuprofen, indomethacin, esmolol, tetracycline, tolbutamide, and verapamil
Medications that may decrease serum digoxin levels include aminoglutethimide, antihistamines, cholestyramine, neomycin, penicillamine, aminoglycosides, oral colestipol, hydantoins, hypoglycemic agents, antineoplastic treatment combinations (including carmustine, bleomycin, methotrexate, cytarabine, doxorubicin, cyclophosphamide, vincristine, procarbazine), aluminum or magnesium antacids, rifampin, sucralfate, sulfasalazine, barbiturates, kaolin/pectin, and aminosalicylic acid
Documented hypersensitivity; beriberi; heart disease; idiopathic hypertrophic subaortic stenosis; constrictive pericarditis; carotid sinus syndrome
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Hypokalemia may reduce positive inotropic effect; IV calcium may produce arrhythmias in digitalized patients; hypercalcemia predisposes patient to digitalis toxicity, and hypocalcemia can make digoxin ineffective until serum calcium levels normal; magnesium replacement therapy must be instituted in patients with hypomagnesemia to prevent digitalis toxicity; patients diagnosed with incomplete AV block may progress to complete block when treated with digoxin; exercise caution in hypothyroidism, hypoxia, and acute myocarditis
Vasodilators
These agents are used to reduce ventricular filling pressure. Avoid excessive decrease in preload and diastolic filling.
Hydralazine (Apresoline)
Decreases systemic resistance through direct vasodilation of arterioles.
Adult
10-20 mg/dose IV q4-6h prn initially; increase to 40 mg/dose prn; change to PO therapy as soon as possible
Pediatric
0.1-0.2 mg/kg/dose IV q4-6h prn; not to exceed 20 mg or 1.7-3.5 mg/kg/d divided in 4-6 doses
MAOIs and beta-blockers may increase toxicity; indomethacin may decrease pharmacologic effects
Documented hypersensitivity; mitral valve rheumatic heart disease
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Has been implicated in myocardial infarction; caution in suspected coronary artery disease
Isosorbide dinitrate and hydralazine (BiDil)
Fixed-dose combination of isosorbide dinitrate (20 mg/tab), a vasodilator with effects on both arteries and veins, and hydralazine (37.5 mg/tab), a predominantly arterial vasodilator. Indicated for heart failure in blacks, based in part on results from African American Heart Failure Trial. Two previous trials in the general population of patients with severe heart failure found no benefit but suggested benefit in patients who are black. Compared with placebo, blacks showed 43% reduction in mortality rate, 39% decrease in hospitalization rate, and decrease in symptoms from heart failure.
Adult
1 tab PO tid; may titrate upward, not to exceed 2 tab tid
Pediatric
Not established
Hydralazine may increase propranolol, metoprolol, and lisinopril AUC and Cmax; isosorbide dinitrate may cause additive vasodilating effects with other vasodilators (eg, sildenafil [Viagra], vardenafil [Levitra]), especially when coadministered with alcohol
Documented hypersensitivity; allergy to organic nitrates
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
May cause symptomatic hypotension even with small doses; careful hemodynamic monitoring required if administered in patients with acute MI
Hydralazine: May cause SLE-like symptoms, including glomerulonephritis, tachycardia, hypotension, and peripheral neuritis (pyridoxine therapy may be required)
Isosorbide dinitrate: If hypotension exists, may aggravate angina associated with hypertrophic cardiomyopathy
Anticoagulants
These agents are used to prevent embolism from ventricular thrombus.
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.
Adult
5-15 mg/d PO qd for 2-5 d; adjust dose according to desired INR
Pediatric
0.05-0.34 mg/kg/d PO; adjust dose according to desired INR
Infants may require doses at, or near, high end of this range
Drugs that may decrease anticoagulant effects include griseofulvin, carbamazepine, glutethimide, estrogens, nafcillin, phenytoin, rifampin, barbiturates, cholestyramine, colestipol, vitamin K, spironolactone, oral contraceptives, and sucralfate
Medications that may increase anticoagulant effects include oral antibiotics, phenylbutazone, salicylates, sulfonamides, chloral hydrate, clofibrate, diazoxide, anabolic steroids, ketoconazole, ethacrynic acid, miconazole, nalidixic acid, sulfonylureas, allopurinol, chloramphenicol, cimetidine, disulfiram, metronidazole, phenylbutazone, phenytoin, propoxyphene, sulfonamides, gemfibrozil, acetaminophen, and sulindac
Documented hypersensitivity; severe liver or kidney disease; open wounds; GI ulcers
Pregnancy
D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus
Precautions
Do not switch brands after achieving satisfactory therapeutic response; caution in active tuberculosis or diabetes and in patients with protein C or S deficiency (they are at risk of developing skin necrosis)
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.
Adult
Loading dose: 40-170 U/kg IV
Maintenance dose: 15-25 U/kg/h IV; increase dose by 5 U/kg/h IV q4h prn as indicated by aPTT results
Pediatric
Loading dose: 50 U/kg IV
Maintenance dose: 15-25 U/kg/h IV; increase dose by 2-4 U/kg/h IV q6-8h prn as indicated by aPTT results
Digoxin, nicotine, tetracycline, and antihistamines may decrease effects; NSAIDs, aspirin, dextran, dipyridamole, and hydroxychloroquine may increase toxicity
Documented hypersensitivity; subacute bacterial endocarditis; active bleeding; history of heparin-induced thrombocytopenia
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
In neonates, preservative-free heparin recommended to avoid possible toxic reaction (gasping syndrome) to benzyl alcohol, which is used as preservative; caution in severe hypotension and shock
More on Cardiomyopathy, Restrictive |
| Overview: Cardiomyopathy, Restrictive |
| Differential Diagnoses & Workup: Cardiomyopathy, Restrictive |
 Treatment & Medication: Cardiomyopathy, Restrictive |
| Follow-up: Cardiomyopathy, Restrictive |
| References |
| « Previous Page | Next Page » |
References
Braunwald E, Abelmann WH. Atlas of Heart Diseases. Vol 2. 1994:53-61.
Davies MJ, Mann JM. Systemic pathology. In: The Cardiovascular System. Vol 10. 1995:1409-16.
Goldstein JA. Differentiation of constrictive pericarditis and restrictive cardiomyopathy. ACC Ed Highlights. 1998;Fall:14-22.
Higano ST, Azrak E, Tahirkheli NK, Kern MJ. Hemodynamic rounds series II: hemodynamics of constrictive physiology: influence of respiratory dynamics on ventricular pressures. Catheter Cardiovasc Interv. Apr 1999;46(4):473-86. [Medline].
Kasper DL, Braunwald E, Fauci AS, eds. Harrison's Principles of Internal Medicine. McGraw-Hill; 2005:chap 221.
Kushwaha SS, Fallon JT, Fuster V. Restrictive cardiomyopathy. N Engl J Med. Jan 23 1997;336(4):267-76. [Medline].
Schlant RC, Alexander RW, eds. The Heart. McGraw-Hill; 1994:1637-45.
Tintinalli JE, Kelen GD, Stapczynski JS, eds. Emergency Medicine: A Comprehensive Study Guide. McGraw-Hill;2004:381.
Wald DS, Gray HH. Restrictive cardiomyopathy in systemic amyloidosis. QJM. May 2003;96(5):380-2. [Medline].
Willerson JT, Cohn JN, ed. Cardiovascular Medicine. Churchill Livingstone; 1995:871-86.
Further Reading
Keywords
diastolic dysfunction, restrictive cardiomyopathy, endomyocardial fibrosis, EMF, dip and plateau configuration, dip and plateau pattern, square root pattern, square root configuration, heart failure, cardiac cirrhosis, thromboembolism, low-output cardiac failure
