January 14, 2007

Cardiac Neoplasms, Primary

Synonyms and related keywords: primary cardiac neoplasms, cardiac tumor, myxoma, Carney complex, atrial myxoma, intracardiac tumor mass, primary neoplasm, rhabdomyoma, fibroma, fibroelastoma, hemangioma, lipoma, teratoma, hamartoma, malignant tumor, benign tumor


INTRODUCTION

Background: The most common primary cardiac tumor is the atrial myxoma, which accounts for 40-50% of all these neoplasms. The remainder of the pathological spectrum includes benign and malignant cell types. Although the overall incidence of the disease is low (0.0001-0.5% in autopsy series), it provides unique diagnostic and therapeutic challenges.

The clinical symptoms caused by cardiac tumors generally are secondary to their mass effect, local invasion, embolization, or constitutional symptoms. An intracardiac tumor mass may obstruct blood flow, compromise valve function, or induce neurological catastrophe secondary to tumor embolization. The location of the tumor determines the type of symptoms produced, which can include syncope, angina, dyspnea, edema, ascites, depression of pump function, cardiomyopathy, and pulmonary hypertension. Some tumors produce no symptoms and are found incidentally as a consequence of secondary symptoms, eg, stroke or evidence of peripheral embolization.

Most benign tumors can be resected completely with excellent outcomes. Consider heart transplantation in those instances when the benign tumor is too large to resect. Resection is the treatment of choice for malignant cardiac tumors; however, long-term results are dismal, even with the addition of adjuvant therapy.

Pathophysiology: Several types of tumors can arise in the heart, depending upon the tissues and structures involved. Primary neoplasms may arise from endocardium, valvular structures, primitive tissue rests, and the conduction system. Secondary or metastatic neoplasms arise from hematologic spread of the originating tissue. The physiologic derangements induced by the tumor are dependent upon the location of the mass and the tissue from which it arises.

Frequency:

Mortality/Morbidity:

Race: Primary cardiac tumors appear to occur equally in all races, unless their presence is connected directly with underlying genetic disorders that demonstrate a race predilection.

Sex: The frequencies of these tumors in males and females are the same.

Age: Cardiac tumors can occur in all age groups.


CLINICAL

History: Myxomas often are asymptomatic, but these tumors can produce symptoms by releasing substances that lead to inflammatory signs, including fever, tachycardia, and tachypnea. Myxomas also present as acute vascular insufficiency of the extremities from embolization. If myxomas are large, they will cause intracardiac obstruction manifested as dyspnea, syncope, or congestive heart failure.

Physical: Often, examination of patients with cardiac tumors yields no abnormal physical findings unless the tumor is large or produces substances that may cause secondary symptoms or findings.

Causes: No distinct cause of cardiac tumors is known.


DIFFERETIALS

Carney Complex


WORKUP

Lab Studies:

Imaging Studies:

Other Tests:

Histologic Findings: Myxomas are gelatinous in nature with rests of spindle cells. If DNA tetraploidy is present, suspect malignancy. Fibroelastomas are composed of endocardium, fibrous tissue, elastic fibers, and smooth muscle cells arranged in a central stock of collagen and a covering of hyperplastic endothelial cells.

Staging: No particular staging exists for cardiac tumors.

TREATMENT

Medical Care: For those tumors presenting with cardiac arrhythmias, standard medical management of the arrhythmia is warranted until the diagnosis is established and definitive therapy undertaken. In the case of paragangliomas, treat hypertension with beta-blockade until resection is undertaken.

Surgical Care: When possible, treatment of choice for cardiac tumors is complete resection. In patients whose tumors are determined to be malignant, adjuvant therapy (ie, chemotherapy, radiation) after resection did not affect the outcome. Cardiac transplantation has been used for benign and malignant tumors. Series using this therapy have been too small to use in predicting outcomes.


MEDICATION

For patients who present with paraganglioma, hypertension, or arrhythmias, beta-blockade is the medical treatment of choice until surgical intervention can be undertaken.

Drug Category: Beta-blockers -- This category of drugs has the potential to suppress ventricular ectopy due to ischemia or excess catecholamines. In the setting of myocardial ischemia, beta-blockers have anti-arrhythmic properties and reduce myocardial oxygen demand secondary to elevations in heart rate and inotropy.
Drug Name
Metoprolol (Lopressor) -- Selective beta1 adrenergic receptor blocker that decreases automaticity of contractions. During IV administration, carefully monitor BP, heart rate, and ECG.
Adult Dose12.5-50 mg PO tid; increase at 1-wk intervals prn to total of 450 mg/d if necessary
Pediatric Dose1-5 mg/kg/d PO divided bid
ContraindicationsDocumented hypersensitivity; uncompensated CHF; bradycardia; asthma; cardiogenic shock; AV conduction abnormalities; chronic obstructive lung disease
InteractionsAluminum salts, barbiturates, NSAIDs, penicillins, calcium salts, cholestyramine, and rifampin may decrease bioavailability and plasma levels, possibly resulting in decreased pharmacologic effects; sparfloxacin, phenothiazines, astemizole, calcium channel blockers, quinidine, flecainide, and contraceptives may increase toxicity; may increase toxicity of digoxin, flecainide, clonidine, epinephrine, nifedipine, prazosin, verapamil, and lidocaine
Pregnancy B - Usually safe but benefits must outweigh the risks.
PrecautionsBeta-adrenergic blockade may reduce signs and symptoms of acute hypoglycemia and may decrease clinical signs of hyperthyroidism; abrupt withdrawal may exacerbate symptoms of hyperthyroidism, including thyroid storm; monitor patient closely and withdraw drug slowly; during IV administration, carefully monitor BP, heart rate, and ECG
Drug Name
Carvedilol (Coreg) -- Nonselective beta-adrenoreceptor blocker with alpha-adrenergic blocking activity of equal potency. No intrinsic sympathomimetic activity has been documented.
Adult Dose3.125-12.5 mg PO bid
Pediatric DoseNot established
ContraindicationsDocumented hypersensitivity; bradycardia; hypotension; severe cardiomyopathy; second- or third-degree heart block; chronic obstructive lung disease; symptomatic hepatic disease
InteractionsInteraction with other anti-arrhythmics and antihypertensives may potentiate clinical effect; may increase blood levels of cyclosporine and digoxin; may diminish hyperglycemic action of glucagon; may alter response to hypoglycemic agents (ie, sulfonylureas); fluoxetine and paroxetine may increase blood level; rifampin may decrease blood level; NSAIDs may blunt antihypertensive effect
Pregnancy C - Safety for use during pregnancy has not been established.
PrecautionsMonitor BP and pulse before taking; use with caution in CHF with slowed AV conduction, peripheral vascular disease, hyperthyroidism, or diabetes mellitus; discontinue if hepatic dysfunction occurs; avoid abrupt withdrawal; discontinue over 1-2 wk
Drug Name
Atenolol (Tenormin) -- Selectively blocks beta1 receptors with little or no effect on beta2 receptors.
Adult Dose25-50 mg PO bid
Pediatric Dose1-2 mg/kg PO qd
ContraindicationsDocumented hypersensitivity; CHF; pulmonary edema; cardiogenic shock; AV conduction abnormalities; heart block (without pacemaker)
InteractionsAluminum salts, barbiturates, calcium salts, cholestyramine, NSAIDs, penicillins, and rifampin may decrease effects; haloperidol, hydralazine, loop diuretics, and MAOIs may increase toxicity
Pregnancy C - Safety for use during pregnancy has not been established.
PrecautionsMonitor BP and pulse before taking; beta-adrenergic blockade may reduce symptoms of acute hypoglycemia and mask signs of hyperthyroidism; abrupt withdrawal may exacerbate symptoms of hyperthyroidism and cause thyroid storm; monitor patients closely and withdraw drug slowly; during IV administration, carefully monitor BP, heart rate, and ECG


FOLLOW-UP

Further Outpatient Care:

Complications:

Prognosis:


MISCELLANEOUS

Medical/Legal Pitfalls:

Special Concerns:

No comments: