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Cardiology > Congenital Heart Disease in the Adult
Congenitally Corrected Transposition
Article Last Updated: Dec 19, 2005
AUTHOR AND EDITOR INFORMATION
Section 1 of 11
Author: Stacy D Fisher, MD, Consulting Staff, Department of Cardiology, Mid-Atlantic Cardiovascular Associates, Sinai Hospital of Baltimore
Stacy D Fisher is a member of the following medical societies: American Medical Association, Phi Beta Kappa, and Sigma Xi
Coauthor(s):
Martin Englehardt, MD, PhD, Clinical Fellow in Cardiology, Department of Medicine, University of Maryland Medical Center;
Wojciech Zareba, MD, PhD, FACC, Associate Director of Heart Research, Associate Professor, Department of Medicine, Division of Cardiology, University of Rochester Medical Center;
Roger Vermilion, MD, Director of Pediatric Echocardiography, Department of Pediatrics, Pediatric Cardiology Unit, Children's Hospital at Strong Memorial Hospital; Associate Professor, University of Rochester School of Medicine
Editors: Park W Willis IV, MD, Sarah Graham Distinguished Professor of Medicine and Pediatrics, University of North Carolina at Chapel Hill School of Medicine; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Marschall S Runge, MD, PhD, Marion Covington Distinguished Professor of Medicine, Vice Dean for Clinical Affairs, Chairman, Department of Medicine, University of North Carolina at Chapel Hill School of Medicine; Amer Suleman, MD, Consultant in Electrophysiology and Cardiovascular Medicine, Department of Internal Medicine, Division of Cardiology, Medical City Dallas Hospital; John Geibel, MD, DSc, MA, Professor, Department of Surgery, Section of Gastrointestinal Medicine and Department of Cellular and Molecular Physiology, Yale University School of Medicine; Director of Surgical Research, Department of Surgery, Yale-New Haven Hospital
Author and Editor Disclosure
Synonyms and related keywords:
congenitally corrected transposition, S-transposition, D-transposition, L-transposition, transposition of the great vessels, atrioventricular and ventriculoarterial discordance, congenital heart defect, multiple cardiac morphological abnormalities and conduction defects, congenital heart disease, cardiac anomalies, complete heart block, heart failure due to right ventricular decompensation or tricuspid valve regurgitation, congenitally corrected transposition of the great arteries, atrial situs, ventricular septal defect, conduction system abnormalities, coronary anatomy, left ventricular outflow tract obstruction, abnormal tricuspid valve morphology, straddling left AV valve, overriding left AV valve, coarctation of the aorta, interruption of the aortic arch, aortic stenosis, subaortic stenosis, hypoplasia of one ventricle, common arterial trunk, abnormal conduction tissue
Background
Congenitally corrected transposition of the great vessels is a rare congenital heart defect associated with multiple cardiac morphological abnormalities and conduction defects.
Pathophysiology
During embryological development, left-handed looping of the heart tube results in atrioventricular (AV) discordance, and the aortopulmonary septum fails to rotate 180°, resulting in ventriculoarterial discordance. Blood flows in an effective sequence, hence the name corrected; however, the right ventricle supports the systemic circulation in this disorder.
Venous blood returns from the body into the right atrium before passing through the mitral valve into a morphological left ventricle. Blood then enters the lungs via the pulmonic valve into the main pulmonary artery. Pulmonary venous blood returns to the left atrium and then passes through the tricuspid valve to the morphological right ventricle, exiting to the aorta via the aortic valve. The aorta is positioned anterior and to the left of the pulmonary artery. In effect, the ventricles are transposed.
Frequency
United States
Data from the Baltimore-Washington Infant Study supported the fact that congenitally corrected transposition is a rare disorder. As many as 40 infants per 100,000 live births are affected by congenitally corrected transposition of the great vessels; this is fewer than 1% of all congenital heart defects.
International
This disorder is reported in 0.5% of patients with congenital heart disease, and the literature reports fewer than 1000 cases. Most pediatric cardiologists have seen multiple cases of congenitally corrected transposition of the great vessels; however, the true prevalence of the malformation is not known.
Mortality/Morbidity
- Ten-year survival rate ranges from 64-83% from the time of diagnosis and is dependent on associated anomalies.
- Freedom reported an operative mortality rate of 6% and a 15-year actuarial survival rate of 48% in a cohort of patients with congenitally corrected transposition of the great vessels at the Hospital for Sick Children in Toronto.
- A rare patient without associated cardiac anomalies may have a much more benign course, and literature documents many examples of these patients being diagnosed in the sixth and seventh decades of life.
- A median age at death of 40 years has been reported in both patients who have undergone operation and those who have not.
History
Symptoms usually reflect associated cardiac anomalies. The uncommon patient with isolated congenitally corrected transposition of the great vessels should be asymptomatic early in life. The diagnosis may be established via a chest radiograph or electrocardiogram performed for another reason; otherwise, this condition is usually diagnosed later in childhood or in early adult life when patients present with complete heart block or heart failure due to right ventricular decompensation or systemic tricuspid valve regurgitation. The most common presenting features are (1) bradycardia related to high-degree AV heart block; (2) a single loud second heart sound, which is often palpable to the left of the sternum, arising from the anteriorly positioned aortic valve; (3) heart murmur due to associated ventricular septal defect, pulmonic stenosis, or tricuspid regurgitation; (4) cyanosis; (5) heart failure; or (6) tachyarrhythmia. Associated cardiac structural findings include the following:
- Atrial situs: The atria are situs solitus in 85-90% of patients.
- Ventricular septal defect: This is the most common associated cardiac malformation, with an incidence of 60-70% in clinical series and nearly 80% in reviews of autopsied cases.
- The defect is usually large and perimembranous in location but can occur in any position along the ventricular septum.
- The perimembranous ventricular septal defect tends to be subpulmonary.
- Subarterial ventricular septal defects, roofed by the semilunar valves, have been described in Asian patients but are uncommon in the Western world.
- The resulting left-to-right shunt is usually large.
- Conduction system abnormalities
- The sinus node is positioned normally but the anatomical situation precludes normal conduction because the AV conduction tissue is profoundly abnormal. The normal AV node cannot give rise to the penetrating AV bundle. An anomalous second AV node is the functional AV conduction system in many patients, generally located beneath the opening of the right atrial appendage at the lateral margin between the pulmonic valve and the mitral valve; thus, the node has an anterior position and gives rise to the AV bundle immediately underneath the right anterior pulmonic valve leaflet. This accessory node is not always present and may be hypoplastic or nonfunctional.
- Complete heart block occurs in 30% of patients and may be present at birth or develop at a rate of 2% per year. Other conduction disturbances described include sick sinus syndrome, atrial flutter, re-entrant AV tachycardia due to an accessory pathway along the tricuspid valve annulus, and ventricular tachycardia.
- Coronary anatomy
- The coronary arteries have a mirror image location.
- Dabizzi et al found coronary artery-ventricular concordance in 11 of 13 patients who underwent angiography. Early entrapment of coronaries in fat or myocardium is also common in this cohort of patients.
- Left ventricular outflow tract obstruction
- Left ventricular outflow tract obstruction (pulmonary outflow tract) occurs in 30-50% of patients and is typically associated with a ventricular septal defect. Freedom reported that, of patients with pulmonary outflow tract obstruction and a ventricular septal defect, approximately one third have tricuspid valve deformities.
- Multiple obstructive lesions have been described, including wedging of the outflow tract by inverted mitral and tricuspid valves, fixed infundibular and valvar pulmonic stenosis, tissue bags derived from intact or perforated membranous septum, blood cysts attached to the pulmonary valve, or a subpulmonic tag originating from both sides of the ventricular septum.
- Abnormal tricuspid valve morphology: Incidence is 90% in autopsy series, but clinically relevant abnormalities are less common and include dysplasia (malformed or imperforate leaflets), apical displacement of the septal leaflet, or straddling and overriding of an inlet ventricular septal defect.
- Straddling or overriding left AV valve (also abnormalities of cusp number or tension apparatus)
- Coarctation of the aorta
- Interruption of the aortic arch
- Aortic or subaortic stenosis
- Hypoplasia of one ventricle: Usually, the disturbed AV valve is ipsilateral to the hypoplastic chamber.
- Common arterial trunk (functional or anatomic aortic atresia)
- Abnormal conduction tissue
Physical
The physical findings depend on the associated anomalies.
- In patients with large left-to-right shunts, the precordium is hyperdynamic, with evidence of cardiac enlargement.
- Individuals with pulmonic stenosis tend to have a relatively quiet precordium, and cyanosis is prominent.
- A loud and often palpable single second heart sound is commonly present at the left sternal border and is related to the anterior and leftward position of the aorta.
- The murmur of left AV valve (tricuspid) regurgitation may be mistaken for the typical pansystolic murmur of ventricular septal defect since it is often maximal at the fourth intercostal space near the sternum rather than at the apex, reflecting the side by side orientation of the ventricles in congenitally corrected transposition with the ventricular septum in the sagittal plane.
- Although the murmur of pulmonary stenosis is often heard well at the pulmonary area, it may be loudest lower on the left side or at the aortic area, because of the inferior and posteriorly displaced pulmonary valve.
Causes
Causes and exposures associated with congenitally corrected transposition of the great arteries have not been identified clearly.
- A substantial number of patients with congenital heart disease have a deletion of chromosome band 22q11. These deletions have been associated with abnormalities of the pulmonary arteries and aortic arch or its major branches regardless of the intracardiac anatomy (Goldmuntz, 1998). Rarely, these deletions are found in patients with transposition of the great vessels. In one series, none of 45 patients with transposition had the deletion.
Cyanosis
Ventricular Septal Defect
Lab Studies
- Cyanotic conditions may be associated with elevations in red cell volume reflected in the hemoglobin and hematocrit. This elevation is a reactive process to the body's demand for oxygen and is not a primary polycythemia. CBC count, clotting profile, renal function, and ferritin and uric acid levels should be measured.
Imaging Studies
- Echocardiography either in utero or by transthoracic or transesophageal imaging generally confirms the diagnosis (see Images 1-2).
- Chest radiography reveals parallel great vessels. The upper left heart border is formed by the aorta and appears straight, and the pulmonary artery knob is absent because of the rightward, posterior displacement of the artery.
- Transesophageal echocardiography (TEE) may be needed to assess ventricular function, AV valve regurgitation, and pulmonary outflow tract if this information is not provided by transthoracic imaging, particularly in the patient who has undergone an operation.
- Nuclear cardiology assessment of ventricular function may be indicated. Radionuclide angiography and MRI usually better report right ventricular function compared with echocardiography. MRI evaluates ventricular volumes, ventricular function, or conduit function.
Other Tests
- Electrocardiography is affected by the associated cardiac anomalies but commonly shows AV block, atrial arrhythmias, and abnormal initial ventricular activation due to disordered anatomy of the conduction system. With ventricular inversion, the ventricular bundle branches are inverted and the initial activation is oriented from right-to-left. This results in reversal of the normal Q-wave pattern in the precordial leads such that Q waves are present in the right precordial leads but absent in the left precordial leads.
- A Holter monitor is used for assessment of AV block and atrial arrhythmia.
Procedures
- Cardiac catheterization carries a significant risk of inducing transient or complete heart block.
- Use caution. Transient or permanent complete heart block may be induced in this condition because the conduction system lies just below the pulmonic valve.
- Always use a balloon-tipped catheter to approach the pulmonic valve. Always have transvenous pacing capability available during this procedure.
- Limit catheterization to assessment of pulmonic stenosis, shunt volume, pulmonary vascular resistance before and in response to therapy, and angiography in preparation for reparative surgery.
Histologic Findings
Anderson et al identified both a normal-appearing AV node in the usual position without connections to a penetrating bundle and an accessory AV node located in the right atrium at the junction of the mitral valve and the left border of the right atrial appendage. This second AV node connects directly to an aberrantly located penetrating bundle. The bundle passes laterally onto the pulmonary outflow tract just below the pulmonic valve, then descends to the interventricular septum, remaining on the right side of the septum rather than the left side (ie, normal system). The course varies depending on the integrity of the ventricular septum.
Medical Care
- Connelly et al reported infective endocarditis in as many as 11% of a 52-patient series. Antibiotic prophylaxis is indicated according to the recommendations of the American Heart Association.
- Management of heart failure may entail use of diuretic drugs, digitalis, beta-blockers, and/or angiotensin-converting enzyme (ACE) inhibitor therapy. All are helpful for symptomatic therapy in particular individuals, but none are demonstrated to improve mortality rate in patients with congenital heart disease.
Surgical Care
Surgery is recommended only for symptomatic associated lesions and when significant hemodynamic benefit is expected.
- Common postoperative complications include complete heart block and progressive tricuspid regurgitation, even when these anatomic structures are not manipulated directly.
- The altered location of a fragile conduction system and the mirror image coronary anatomy may complicate surgical repair. The right-sided coronary artery often divides into the anterior descending and circumflex branches, which supply the morphological left ventricle. This complicates placement of a conduit in patients to relieve pulmonic stenosis.
- Ventricular septal defect closure is generally performed when symptoms of CHF or failure to thrive do not respond to medical therapy or when pulmonary vascular pressures are increasing. Operative mortality rate among 15 patients with ventricular septal defect reported by Termignon et al was 13%, with 33% requiring permanent pacemaker implantation for complete heart block. Two patients had late deaths and 6 required reoperation for tricuspid valve replacement.
- Tricuspid valve replacement can be performed for severe tricuspid incompetence. Repair of the dysplastic or displaced valve is not usually feasible.
- Switch procedures attempt to correct the underlying malformation anatomically, trying to minimize the risk of heart block or tricuspid incompetence.
- The atrial and ventricular double switch procedure is performed when pulmonic stenosis and a large ventricular septal defect are present. Feasibility of the repair depends on the location of the ventricular septal defect. The repair requires proximity of a ventricular septal defect to the aorta. Chordal malattachments or deformation of the mitral valve inhibiting support of systemic pressures may exclude this option.
- The Rastelli procedure, originally described by Gian Carlo Rastelli in 1969, for patients with D-transposition of the great arteries, large ventricular septal defect, and naturally occurring pulmonary outflow obstruction involves routing the left ventricle to the aorta via a prosthetic baffle through the ventricular septal defect into the right ventricle to the aortic valve and placing a conduit from the right ventricle to the pulmonary artery bifurcation. In patients with moderate pulmonary stenosis, self-palliation has occurred and infants can survive for many years without intervention.
- The atrial switch for L-transposition takes the form of the Senning or Mustard procedure with additional repair of any ventricular septal defect. These procedures involve intra-atrial baffles to route venous blood toward the left ventricle and pulmonary artery, and oxygenated blood from the pulmonary veins into the right ventricle and out to the body. The Senning procedure is technically advanced to better preserve intrinsic AV nodal function. The right ventricle and tricuspid valve remain systemic.
- The arterial switch operation is the most current procedure available, generally performed within 2 weeks of birth. In this procedure, the left ventricle must have tolerated near-systemic pressures prior to the switch. Pulmonary artery banding prior to a definitive repair can prepare the ventricle if a sufficient ventricular septal defect is not present; however, based on results from repair of complete transposition of the great arteries, long-term outcome after atrial switch is a concern. Late complications include atrial arrhythmias and vena cava or pulmonary venous obstruction.
- In a study of 52 patients reported by Termignon et al, the operative mortality rate of a classic repair of congenitally corrected transposition of the great arteries and ventricular septal defect was 16% and the rate of complete heart block was 24% after the repair. Six additional late deaths and 5 patients who required reoperation for tricuspid valve replacement were also listed. Survival rates were 83% at 1 year and 55% at 5 years after the repair.
- Early pacemaker placement is recommended in the setting of complete heart block either during or after surgical intervention or if any significant associated defect, such as cardiomegaly, decreased right ventricular function, symptomatic bradycardia, or heart failure, is present.
- Percutaneous pulmonary valvuloplasty is not recommended in patients with transposition of the great vessels because of expected complete heart block.
Activity
The reduced ability of the right ventricle to support systemic pressure and associated anomalies limit activity. The 1994 Bethesda Conference included patients with congenitally corrected transposition of the great vessels, and specific recommendations to limit activity were not made. Individual assessment should include serial evaluations of right ventricular function.
Medications include antibiotic prophylaxis for procedures or dental work and standard therapy for heart failure (diuretic drugs, digitalis, beta-blockers, and ACE inhibitors). All are helpful for symptomatic therapy, but none are demonstrated to improve mortality rates.
Drug Category: Antibiotics
Empiric antimicrobial therapy should cover all likely pathogens in the context of this clinical setting.
| Drug Name | Amoxicillin (Amoxil, Trimox) |
| Description | Interferes with synthesis of cell wall mucopeptides during active multiplication, resulting in bactericidal activity against susceptible bacteria. Recommended prophylactic regimen for dental, oral, or upper respiratory procedures per American Heart Association guidelines. |
| Adult Dose | 2 g PO 1 h before procedure |
| Pediatric Dose | 50 mg/kg PO 1 h before procedure; not to exceed 2 g/dose |
| Contraindications | Documented hypersensitivity |
| Interactions | Reduces efficacy of oral contraceptives; may increase PT in patients on warfarin |
| Pregnancy | B - Usually safe but benefits must outweigh the risks.
|
| Precautions | Adjust dose in renal impairment |
| Drug Name | Ampicillin (Omnipen, Principen) |
| Description | For prophylaxis in patients undergoing dental, oral, or respiratory tract procedures. Patients unable to take oral medications may be given ampicillin IV. |
| Adult Dose | 2 g IV/IM 30 min prior to procedure |
| Pediatric Dose | 50 mg/kg IV/IM 30 min prior to procedure |
| Contraindications | Documented hypersensitivity |
| Interactions | Probenecid and disulfiram elevate levels; allopurinol decreases effects and has additive effects on ampicillin rash; may decrease effects of oral contraceptives |
| Pregnancy | B - Usually safe but benefits must outweigh the risks.
|
| Precautions | Adjust dose in renal failure; evaluate rash and differentiate from hypersensitivity reaction |
| Drug Name | Clindamycin (Cleocin) |
| Description | Used in penicillin-allergic patients undergoing dental, oral, or respiratory tract procedures. |
| Adult Dose | 600 mg PO/IV 1 h prior to procedure |
| Pediatric Dose | 20 mg/kg PO/IV 1 h prior to procedure; not to exceed 600 mg/d |
| Contraindications | Documented hypersensitivity; regional enteritis; ulcerative colitis; hepatic impairment; antibiotic-associated colitis |
| Interactions | Increases duration of neuromuscular blockade induced by tubocurarine and pancuronium; erythromycin may antagonize effects; antidiarrheals may delay absorption |
| Pregnancy | B - Usually safe but benefits must outweigh the risks.
|
| Precautions | Adjust dose in severe hepatic dysfunction; no adjustment necessary in renal insufficiency; associated with severe and possibly fatal colitis |
Drug Category: Diuretics
These agents are used for treatment of pulmonary or hepatic congestion and peripheral edema due to heart failure.
| Drug Name | Furosemide (Lasix) |
| Description | Increases excretion of water by interfering with chloride-binding cotransport system in kidney, which, in turn, inhibits sodium and chloride reabsorption in ascending loop of Henle and distal renal tubule. Titrate dose according to response. Available as 20-, 40-, and 80-mg tablets. |
| Adult Dose | 20-80 mg/d PO/IV, titrate up to 600 mg/d divided tid/qid |
| Pediatric Dose | 2 mg/kg/dose PO initial, titrate 1 mg/kg q6-8h; not to exceed 6 mg/kg/dose; do not administer more often than q6h |
| Contraindications | Documented hypersensitivity; hepatic coma; anuria; severe electrolyte depletion |
| Interactions | Metformin decreases concentrations; interferes with hypoglycemic effect of diabetic therapeutic agents and antagonizes muscle-relaxing effect of tubocurarine; aminoglycosides increase risk of auditory toxicity—hearing loss of varying degrees may occur; may increase anticoagulant activity of warfarin; may increase plasma lithium levels and toxicity |
| Pregnancy | C - Safety for use during pregnancy has not been established.
|
| Precautions | Perform frequent serum electrolyte, carbon dioxide, glucose, creatinine, uric acid, calcium, and BUN determinations during first few months of therapy and periodically thereafter; caution in heart disease, arrhythmias may occur |
Drug Category: Angiotensin converting enzyme inhibitors
These agents offer a mortality benefit in CHF and left ventricular dysfunction in patients with structurally normal hearts.
| Drug Name | Lisinopril (Prinivil, Zestril) |
| Description | Prevents conversion of angiotensin I to angiotensin II, a potent vasoconstrictor, resulting in lower aldosterone secretion. Not recommended in patients with one kidney. |
| Adult Dose | 20-40 mg/d PO, increase as BP permits |
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity |
| Interactions | May increase digoxin, lithium, and allopurinol levels; probenecid may increase levels; diuretics increase hypotensive effects; NSAIDs may reduce hypotensive effects |
| Pregnancy | C - Safety for use during pregnancy has not been established.
|
| Precautions | Category D in second and third trimester of pregnancy; caution in renal impairment, valvular stenosis, or severe CHF; monitor electrolytes because of risk for hyperkalemia |
| Drug Name | Ramipril (Altace) |
| Description | Prevents conversion of angiotensin I to angiotensin II, a potent vasoconstrictor, resulting in lower aldosterone secretion. |
| Adult Dose | 10 mg PO qd |
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity; history of angioedema |
| Interactions | May increase digoxin, lithium, and allopurinol levels; probenecid may increase levels; diuretics increase hypotensive effects; NSAIDs may reduce hypotensive effects |
| Pregnancy | C - Safety for use during pregnancy has not been established.
|
| Precautions | Category D in second and third trimester of pregnancy; caution in renal impairment, valvular stenosis, or severe CHF; monitor electrolytes because of risk for hyperkalemia |
| Drug Name | Captopril (Capoten) |
| Description | Prevents conversion of angiotensin I to angiotensin II, a potent vasoconstrictor, resulting in lower aldosterone secretion. |
| Adult Dose | Dosage goal: 50 mg PO tid Range: 6.25-100 mg PO tid |
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity |
| Interactions | NSAIDs may reduce hypotensive effects; may increase digoxin, lithium, and allopurinol levels; rifampin decreases levels; probenecid may increase levels; diuretics may increase hypotensive effects |
| Pregnancy | C - Safety for use during pregnancy has not been established.
|
| Precautions | Category D in second and third trimester of pregnancy; caution in renal impairment, valvular stenosis, or severe CHF; monitor electrolytes because of risk for hyperkalemia |
| Drug Name | Enalapril (Vasotec) |
| Description | Competitive inhibitor of ACE. Reduces angiotensin II levels, decreases aldosterone secretion. |
| Adult Dose | 2.5 mg PO bid initial, titrate to goal of 20 mg PO bid |
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity; history of angioedema; hyperkalemia; pregnancy |
| Interactions | NSAIDs may reduce hypotensive effects; may increase digoxin, lithium, and allopurinol levels; rifampin decreases levels; probenecid may increase levels; diuretics may increase hypotensive effects |
| Pregnancy | C - Safety for use during pregnancy has not been established.
|
| Precautions | Category D in second and third trimester of pregnancy; caution in renal impairment, valvular stenosis, or severe CHF; monitor electrolytes because of risk for hyperkalemia |
| Drug Name | Quinapril (Accupril) |
| Description | Prevents conversion of angiotensin I to angiotensin II, a potent vasoconstrictor, resulting in lower aldosterone secretion. |
| Adult Dose | 10-20 mg PO qd initial, adjust with at least 2-wk intervals; most adults will take 20, 40, or 80 mg in single or divided doses |
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity; history of angioedema |
| Interactions | NSAIDs may reduce hypotensive effects; may increase digoxin, lithium, and allopurinol levels; rifampin decreases levels; probenecid may increase levels; diuretics may increase hypotensive effects |
| Pregnancy | D - Unsafe in pregnancy
|
| Precautions | Caution in renal impairment, valvular stenosis, or severe CHF; monitor electrolytes because of risk for hyperkalemia |
Drug Category: Cardiac glycosides
These agents inhibit sodium-potassium adenosine triphosphatase (ATPase), increasing intracellular calcium. Used in treatment of mild to moderately severe CHF.
| Drug Name | Digoxin (Lanoxin) |
| Description | Cardiac glycoside with direct inotropic effects in addition to indirect effects on cardiovascular system. Acts directly on cardiac muscle, increasing myocardial systolic contractions through intracellular calcium release. Its indirect actions result in increased carotid sinus nerve activity and enhanced sympathetic withdrawal for any given increase in mean arterial pressure. |
| Adult Dose | 0.125-0.5 mg PO qd |
| Pediatric Dose | Divided dosing recommended and must be titrated by response; dosed according to renal function and body size 5-10 years: 20-35 mcg/kg PO >10 years: 10-15 mcg/kg PO Maintenance: 25-35% of PO loading dose |
| Contraindications | Documented hypersensitivity; beriberi heart disease; idiopathic hypertrophic subaortic stenosis; constrictive pericarditis; carotid sinus syndrome; ventricular fibrillation |
| Interactions | 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 may increase levels; 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 may decrease serum levels |
| Pregnancy | C - Safety for use during pregnancy has not been established.
|
| Precautions | Hypokalemia may reduce positive inotropic effect of digitalis; IV calcium may produce arrhythmias in digitalized patients; hypercalcemia predisposes patient to digitalis toxicity; hypocalcemia can make digoxin ineffective until serum calcium levels are normal; institute magnesium replacement therapy 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; adjust dose in renal impairment |
Drug Category: Beta-blockers
These agents have not been studied in patients with right systemic ventricle heart failure. Beta-blockers have mortality benefits in the general heart failure population and must be considered in the population of patients with complex congenital heart disease. Initiate beta-blockers only in patients whose condition is stable, without CHF symptoms, and titrate slowly.
| Drug Name | Metoprolol (Lopressor, Toprol XL) |
| Description | Selective beta1-adrenergic receptor blocker that decreases automaticity of contractions. During IV administration, carefully monitor BP, heart rate, and ECG. |
| Adult Dose | 25 mg PO bid, titrate as tolerated; not to exceed 100 mg PO bid |
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity; uncompensated CHF; bradycardia; asthma; cardiogenic shock; AV conduction abnormalities |
| Interactions | Aluminum salts, barbiturates, NSAIDs, penicillins, calcium salts, cholestyramine, and rifampin may decrease bioavailability and plasma levels, possibly resulting in decreased pharmacologic effects; sparfloxacin, phenothiazines, astemizole (recalled from US market), calcium channel blockers, quinidine, flecainide, and oral 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.
|
| Precautions | Beta-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) |
| Description | Used to reduce disease progression in CHF. Effects include beta-blockade, alpha1-blockade, and antioxidant properties. |
| Adult Dose | 3.125 mg PO bid initial, titrate slowly (1- to 3-wk intervals) up to 25 mg PO bid |
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity; uncompensated CHF; bradycardia; asthma; cardiogenic shock; AV conduction abnormalities not treated with permanent pacemaker therapy |
| Interactions | Aluminum salts, barbiturates, NSAIDs, penicillins, calcium salts, cholestyramine, and rifampin may decrease bioavailability and plasma levels, possibly resulting in decreased pharmacologic effects; sparfloxacin, phenothiazines, astemizole (recalled from US market), calcium channel blockers, quinidine, flecainide, and oral 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.
|
| Precautions | Beta-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 |
Deterrence/Prevention:
- Serial echocardiograms to monitor right ventricular (ie, systemic ventricular) size and function, and tricuspid (systemic AV) valve regurgitation can help to time operative repair and assess effects of medical intervention. Data are emerging using right ventricular radionuclide angiography and magnetic resonance angiography for both perfusion and function assessments. Multiple gated acquisition (MUGA) scans can also accurately describe right ventricular function and dimension.
- Guidelines for the Clinical Application of Echocardiography by an ACC/AHA Task Force suggest that class I indications for follow-up echocardiograms in patients with known congenital heart disease include any change in clinical findings, any uncertainty of the original diagnosis or of the structural abnormalities or hemodynamics, or periodic monitoring for those whose ventricular function and AV valve regurgitation must be followed.
- The timing of periodic monitoring is not specified. Most centers monitor patients with serial echocardiography; more frequent examinations are warranted for any change in clinical status.
- Dobutamine stress echocardiography may also be helpful. In asymptomatic children after arterial switch surgery, baseline left ventricular function is often mildly impaired with reversible areas of ischemia revealed, despite normal coronary perfusion.
Complications:
- Major postoperative residual complications include contractile dysfunction of the systemic right ventricle, progressive tricuspid (systemic AV) regurgitation, complete heart block, atrial or ventricular arrhythmias, and infective endocarditis. Patients may develop conduit or homograph dysfunction postoperatively.
- Systemic AV valve regurgitation is well described after surgery even when the valve has not been directly manipulated.
Prognosis:
- Prognosis depends on AV conduction, arrhythmias, structural abnormalities, and degree of hemodynamic disturbance.
- Sudden death may be related to the onset of complete heart block or atrial or ventricular arrhythmias.
- Right ventricular failure can develop over time. Poor prognostic indicators include cyanosis, polycythemia, pulmonary vascular obstructive disease, tricuspid regurgitation, younger age at surgery, larger preoperative shunt size, and lower right ventricular ejection fraction.
Patient Education:
- Pregnancy counseling
- Infective endocarditis prophylaxis
- Moderate and not heavy exercise routines
Medical/Legal Pitfalls
- Cardiac catheterization carries a high risk of inducing complete heart block. Use a balloon-tipped catheter to approach the pulmonic valve and have immediate access to transvenous pacing available during the procedure.
- Failure to recommend permanent pacemaker implantation for symptomatic bradycardia is a potential pitfall.
- Failure to diagnose associated anomalies, including coronary artery anomalies, may have a significant impact on intended surgery.
- Performing phlebotomy on a patient when hematocrit is less than 70 (unless the patient is symptomatic) and performing phlebotomy without volume replacement are potential pitfalls.
- Monitoring iron levels is important in patients who require repeated phlebotomy. Early therapy is recommended for low levels; however, once-a-day dosing with cessation as soon as the hemoglobin level starts to rise is important. Iron therapy at routine doses (ie, 3 times per day) is rarely indicated, and close monitoring in patients with cyanosis is essential to avoid thrombocytosis.
- Failure to recommend antibiotic prophylaxis for infective endocarditis is a potential pitfall.
Special Concerns
- Pregnancy
- The ability of the right ventricle to sustain systemic pressures is of even greater concern in the case of pregnancy, when blood volume increases to approximately 50% above normal by 32 weeks' gestation.
- A retrospective study by Therrien et al of 45 pregnancies in 19 women with congenitally corrected transposition of the great arteries revealed heart failure in 3 patients, worsening cyanosis in 1 patient, and cerebrovascular accident in 1 patient. No maternal deaths occurred. Pregnancies resulted in 27 live births (5 premature), 12 miscarriages, and 6 elective terminations. One live infant had congenital heart disease (hypoplastic left heart syndrome). Maternal cyanosis was the greatest predictor of miscarriage.
- Genoni et al reported retrospectively on the risk of pregnancy in 342 patients with transposition of the great arteries who have undergone atrial repair. Of 231 known late survivors, 48 were women older than 18 years who were interviewed about possible reproductive plans and previous pregnancies. Of the 48 women, 66% remained asymptomatic, 29% had mild-to-moderate cardiac symptoms, and 5% suffered from severe cardiac symptoms (New York Heart Association grade III-IV). Thirty-six of the 48 women wished to bear children. At the time this study was reported, pregnancies in the 48 women had resulted in 10 live births, 2 spontaneous first trimester abortions, and 1 induced abortion at 16 weeks. During pregnancy, 1 case of cardiac deterioration was noted. No evidence existed of congenital heart disease in the children.
- Rheumatic fever with involvement of the tricuspid valve may be an issue in this patient population.
| Media file 1:
Subcostal view of a 1-year-old child with L-transposition of the great arteries, valvular and subvalvular pulmonic stenosis, and a moderate outlet ventriculoseptal defect (VSD). Note the ventriculoarterial discordance. Note the posterior, rightward position of the pulmonary artery. [PA = pulmonary artery, LV = left ventricle, RV = right ventricle]. |
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Media type: Photo
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| Media file 2:
Apical image revealing atrioventricular discordance. Note the pulmonary venous return into the left atrium, with sequential flow through the tricuspid valve to the right ventricle. The right ventricle is systemic. [LA = left atrium, RA = right atrium, LV = left ventricle, RV = right ventricle]. |
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| Media file 3:
Post-Rastelli repair with left ventricle to aortic baffle through a ventriculoseptal defect (VSD) complicated by subaortic stenosis. |
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Media type: CT
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| Media file 4:
This image demonstrates a calcified pulmonary homograft anterior and adjacent to the chest wall (right ventricle to pulmonary artery bifurcation) with significant homograft stenosis and prior pulmonary valvular endocarditis (same patient as in Image 3). |
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Media type: CT
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Congenitally Corrected Transposition excerpt Article Last Updated: Dec 19, 2005
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