eMedicine Specialties > Cardiology > Myocardial Disease and Cardiomyopathies
Cardiomyopathy, Restrictive: Treatment & Medication
Updated: Oct 9, 2008
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
Treatment
Medical Care
The goal of treatment in restrictive cardiomyopathy (RCM) is to reduce symptoms by lowering elevated filling pressures without significantly reducing the cardiac output. Presently, no drugs selectively enhance myocardial relaxation. Therefore, current therapy consists predominately of low-dose diuretics to lower the preload. Small initial doses should be administered to avoid hypotension because these patients are frequently extremely sensitive to alterations in left ventricular volume. Higher doses may be needed if the serum albumin level is low secondary to concomitant nephrotic syndrome.
- ACE inhibitors and angiotensin II inhibitors are poorly tolerated in patients with amyloidosis. Even small doses may result in profound hypotension, probably secondary to an autonomic neuropathy.
- Beta-blockers and calcium channel blockers are not documented to improve day-to-day symptoms or to favorably alter the natural history in patients with diastolic heart failure.
- No published data are available on the use of intravenous inotropic or vasodilator drugs.
- Patients with a history of embolization or atrial fibrillation should be anticoagulated. In patients with atrial fibrillation, the rate should be controlled adequately. Removal of the atrial contribution to ventricular filling may worsen the existing diastolic dysfunction, and a rapid ventricular response may further compromise diastolic filling, creating a crisis. Therefore, maintaining sinus rhythm is important, and medications such as amiodarone and beta-blocker are often used. Digoxin should be used with caution because it is potentially arrhythmogenic, particularly in patients with amyloidosis.
- Specific therapy
- Antiplasma cell therapy with melphalan may slow the progress of systemic amyloidosis by stopping production of the paraprotein responsible for the formation of amyloid. The prognosis of patients with primary systemic amyloidosis remains poor, with a median survival of approximately 2 years despite intervention with alkylating-based chemotherapy in selected cases. In specific cases, chemotherapy has dramatic benefits, with improvement in systemic and cardiac manifestations.
- Medical therapy with corticosteroids, cytotoxic agents (eg, hydroxyurea), and interferon is appropriate during the early phase of Loeffler endocarditis and improves symptoms and survival.
- Chelation therapy or venesection is effective in patients with hemochromatosis to decrease the iron overload.
- The treatment of Loeffler endocarditis consists of correctly identifying the condition before the end-stage fibrosis occurs; administration of corticosteroids, cytotoxic agents (eg, hydroxyurea), and interferon to suppress the intense eosinophilic infiltration of the myocardium; and conventional heart failure medication.
Surgical Care
- Patients with idiopathic restrictive cardiomyopathy (RCM) may have fibrosis of the sinoatrial and atrioventricular nodes that result in complete heart block, and, therefore, require permanent pacing. If cardioversion to treat atrial fibrillation is attempted, particularly in patients with amyloidosis, the abnormal sinus node may fail as an effective pacemaker. Patients with sinus node dysfunction and/or advanced conduction system disease also require treatment with implantation of a pacemaker.
- Cardiac transplantation can be considered in highly selected patients with refractory symptoms in idiopathic or familial RCM and amyloidosis. When noncardiac organ involvement is absent, a few patients with amyloidosis have undergone successful cardiac transplantation, combined with postoperative high-dose chemotherapy, to abolish recurrent amyloid production.
- Loeffler endocarditis: Surgical therapy, with excision of the fibrotic endocardium and replacement of the mitral and tricuspid calves, is palliative in the fibrotic stage of the disease but may provide symptomatic improvement. The operative mortality rate is in the range of 15-25%.
- Combined heart and liver transplantation in patients with heart and liver failure due to hemochromatosis has been successful in small numbers of patients. However, early morbidity and mortality is higher in dual organ transplantation than in single organ transplantation.
- Transplantation is a treatment option for cardiac sarcoidosis, but recurrence of sarcoid granulomas can occur in the transplanted heart.
- A surgical approach offers a cure for pericardial constriction but carries a potential for significant morbidity for RCM. Thus, establishing a clear diagnosis is crucial, and the advent of current sophisticated imaging technology helps in that regard. Fewer patients are now needing exploratory open-heart surgery to establish the correct diagnosis.
- Stem cell transplantation used in conjunction with high-dose chemotherapy is still considered experimental by most cardiologists. Its routine use has not yet been established.
- Finally, whether patients who have radiation-induced cardiac diseases are candidates for heart transplant is uncertain. Concerns have been raised as to whether their immune system would allow them to receive the immunosuppressive therapy necessary following the surgical procedure and whether relapse of their malignancy might occur.
Medication
The goals of pharmacotherapy for restrictive cardiomyopathy are to reduce morbidity and prevent complications.
Diuretics
Symptomatic treatment may improve symptoms of venous congestion through elimination of retained fluid and preload reduction.
Hydrochlorothiazide (HydroDIURIL, Esidrix, Microzide)
Inhibits reabsorption of sodium in distal tubules, causing increased excretion of sodium and water as well as potassium and hydrogen ions.
Adult
12.5-100 mg PO qd or in divided doses; may administer qod
Pediatric
Not established
Thiazides may decrease effects of anticoagulants, antigout agents, and sulfonylureas; thiazides may increase toxicity of allopurinol, anesthetics, antineoplastics, calcium salts, loop diuretics, lithium, diazoxide, digitalis, amphotericin B, and nondepolarizing muscle relaxants; ACTH, corticosteroids, and amphotericin B increase hypokalemia risk; orthostatic hypotension may occur with alcohol ingestion
Documented hypersensitivity; anuria; renal decompensation
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Caution in patients with renal and hepatic disease, gout, diabetes mellitus, asthma, postsympathectomy, excessive fluid loss, and SLE; not recommended in breastfeeding women; monitor electrolytes and BUN; potassium supplements or potassium-sparing diuretics may be needed; discontinue if electrolyte disorder develops rapidly; adverse effects include electrolyte disorders (especially hypokalemia), hyperglycemia, hyperuricemia, photosensitivity, orthostatic hypotension, GI disturbances, and adverse lipid values
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 the previous dose until desired diuresis occurs. When treating infants, titrate with 1-mg/kg/dose increments until satisfactory effect achieved.
Adult
20-80 mg/d PO/IV/IM; may repeat or increase after 6-8 h; not to exceed 600 mg/d; watch for volume depletion, electrolyte imbalance, and orthostatic hypotension
Pediatric
Not established
Metformin decreases furosemide concentrations; interferes with hypoglycemic effect of antidiabetic agents and antagonizes muscle-relaxing effect of tubocurarine; auditory toxicity appears to be increased with coadministration of aminoglycosides; hearing loss of varying degrees may occur; anticoagulant activity of warfarin may be enhanced when taken concurrently; increased plasma lithium levels and toxicity are possible when taken concurrently; alcohol and CNS depressants may increase orthostatic hypotension; antagonized by indomethacin; may alter excretion of salicylates; hypokalemia may occur with corticosteroids or ACTH; potentiates antihypertensive effects of succinylcholine
Documented hypersensitivity; hepatic coma; anuria; state of 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
Perform frequent serum electrolyte, CO2, glucose, creatinine, uric acid, calcium, and BUN determinations during first few months of therapy and periodically thereafter; caution in renal or hepatic dysfunction, diabetes, gout, SLE, breastfeeding, and elderly patients; potassium supplementation may be needed; discontinue if progressive renal dysfunction occurs; adverse effects include excessive diuresis, fluid or electrolyte imbalance, GI upset, dizziness, vertigo, paresthesias, orthostatic hypotension, hyperglycemia, jaundice, hyperuricemia, rash, photosensitivity, tinnitus, hearing loss, blood dyscrasias, and renal calcification in premature infants
Nitrates
Used to reduce preload in diastolic dysfunction.
Long-acting Nitroglycerin (Deponit, Nitrostat, Nitrol, Nitro-Bid)
Causes relaxation of vascular smooth muscle by stimulating intracellular cyclic guanosine monophosphate production. Result is a decrease in blood pressure.
Available as lingual pump spray, sublingual tablets, oral tablets, patches, and ointments.
Adult
Spray: 1-2 sprays; dose may be repeated q3-5min as hemodynamics permit; not to exceed 3 sprays in 15 min
Ointment (15 mg/in): Apply 1/2 in every am to chest wall; repeat in 6 h; may increase to 1 in, then to 2 in bid
Patch: Apply 0.2-mg/h patch or 0.4-mg/h patch for 12-14 h/d; remove patch for 10-12 h/d
Sublingual tablets: 0.3- to 0.6-mg tab, 1 tab SL, may repeat in 5 min; not to exceed 3 tab in 15 min
Pediatric
Not recommended
Aspirin may increase nitrate serum concentrations; marked symptomatic orthostatic hypotension may occur with coadministration of calcium channel blockers (dose adjustment of either agent may be necessary); hypotension potentiated by sildenafil, calcium channel blockers, alcohol, vasodilators, antihypertensives, beta-blockers, phenothiazines, and aspirin; may antagonize alteplase or heparin; drugs that cause dry mouth (eg, TCAs, anticholinergics) may interfere with SL dissolution; avoid ergots; tolerance to other forms of nitrates may blunt effects; may interfere with cholesterol tests
Documented hypersensitivity; early MI; severe anemia; shock; postural hypotension; head trauma; increased intracranial pressure; concomitant sildenafil; closed-angle glaucoma; cerebral hemorrhage
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
Caution in acute MI, hypotensive or volume-depleted patients, elderly patients, breastfeeding women, and patients with hypertrophic cardiomyopathy; monitor in heart failure; avoid abrupt cessation; discontinue if blurred vision or dry mouth occurs; adverse reactions include headache, weakness, vertigo, palpitations, orthostatic hypotension, tachycardia, syncope, flushing, rash, and exfoliative dermatitis
Cardiac glycosides
Used to treat atrial fibrillation and systolic dysfunction in RCM.
Digoxin (Lanoxin, Lanoxicaps)
Cardiac glycoside with direct inotropic effects in addition to 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.
Adult
Loading dose: 0.5-0.75 mg PO over 12-24h; 0.25-1.0 mg IV over 12-24h
Maintenance dose: 0.125 mg/d PO
Pediatric
Not established
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 of digitalis; IV calcium may produce arrhythmias in digitalized patients; hypercalcemia predisposes patients to digitalis toxicity; hypocalcemia can make digoxin ineffective until serum calcium levels are 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; caution in patients with hypothyroidism, hypoxia, and acute myocarditis; in patients with renal dysfunction, reduce dose; caution in premature infants, neonates, and breastfeeding women; adverse reactions include GI effects (eg, anorexia, vomiting, diarrhea), CNS effects (eg, blurred or yellow vision, mental disturbances, confusion, headache, weakness, dizziness, apathy), gynecomastia, rash, heart block, and arrhythmias; in children, arrhythmia is the earliest sign of toxicity
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
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Further Reading
Keywords
restrictive cardiomyopathy, RCM, myocardium, Loeffler's endocarditis, chronic endomyocardial fibrosis, diastolic heart failure, primary amyloidosis, eosinophilic, hemochromatosis, glycogen storage disease
