eMedicine Specialties > Pediatrics: Cardiac Disease and Critical Care Medicine > Cardiology
Atrioventricular Septal Defect, Unbalanced: Treatment & Medication
Updated: Aug 27, 2008
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
- Multimedia
Treatment
Medical Care
- Generally, treat congestive heart failure (CHF) with digoxin, diuretics, and ACE inhibitors as needed before surgical palliation and/or repair.
- The most important prerepair medical care involves the decision-making process regarding univentricular versus biventricular repair. A successful biventricular repair requires creation of 2 competent atrioventricular valves (AVVs), and both ventricles must be large enough to carry a full cardiac output.
- Preoperative left ventricular (LV) volume calculations can greatly underestimate the potential volume of the LV once the right ventricle (RV) is unloaded.
- In 1997, Van Son and colleagues predicted postoperative LV volumes based on preoperative echocardiography in patients with RV-dominant unbalanced atrioventricular (AV) septal defects.9 They found that a preoperative indexed volume of greater than 15 mL/m2 was sufficient for a biventricular repair. They also noted that the commonly held notion that the LV should be apex forming is misleading; this is not essential for a successful biventricular repair.
- The use of echocardiography to derive an AVV index has been described. The advantage to this approach is that it is less affected by volume load differences than ventricular cavity volumes. They suggest that a left-to-right AVV area ratio of less than 0.67 in the presence of a large ventricular septal defect (VSD) or ductal-dependent circulation precludes biventricular repair.10
- Neither of these strategies takes into account potential for growth, particularly in small infants.11
Surgical Care
- Surgical techniques for the treatment of patients with AV septal defects have evolved considerably since Lillehei first reported successful repair of an AVC defect using cross-circulation in 1955.12 Results have remarkably improved over the past 20 years.
- Most patients who are eligible for a biventricular repair undergo repair before age 6 months (as with other patients with balanced AV septal defects). Most institutions are comfortable performing a biventricular repair in symptomatic patients aged 3-4 months or younger and can do so with a mortality rate of less than 3%.13
- The following 2 surgical approaches are commonly used with excellent results to repair balanced AV septal defects:
- The 2-patch technique uses a synthetic (eg, Dacron, Gore-Tex) ventricular patch and a separate pericardial atrial patch.
- The 1-patch technique, usually pericardial, covers both the ventricular and atrial components.
- In one study that compared the 2-patch technique with a modified 1-patch technique, the outcomes were similar.14 The modified 1-patch technique was performed with shorter cross-clamp and cardiopulmonary bypass times.
- In patients with severe hypoplasia of one ventricle, the single-ventricle pathway offers the best long-term results, although it is palliative at best. Drinkwater and Laks reported on 34 patients with unbalanced AV septal defects who underwent cavopulmonary shunt procedures between 1988 and 1996.15 Of these patients, 25 (73%) were RV-dominant. The hospital mortality rate was 9% (3 of 34 patients). Of 31 survivors, 3 late deaths occurred (9.6% of patients). Of the 16 patients who underwent completion of the Fontan operation, 1 died in the hospital and 5 late deaths occurred.
- In the early postoperative period, nitric oxide may be beneficial for those patients who have elevated pulmonary vascular resistance.16
Consultations
- Pediatric cardiologist
- Pediatric cardiothoracic surgeon
- Geneticist, if indicated
Diet
- No specific diet is needed.
- Maximizing nutrition and caloric intake is important in every child with CHF symptoms and before surgical repair and/or palliation.
- Increased caloric density of formula is often required for growth.
Activity
- Activity restrictions must be determined on a patient-by-patient basis and vary considerably, depending on whether a 1-ventricle or 2-ventricle repair is achieved.
- In addition, residual defects such as AVV regurgitation or LV outflow tract obstruction may influence exercise performance.
- After staged completion, patients who underwent single-ventricle repair may experience as much as 80% of normal exercise tolerance.
Medication
No specific or recommended drug therapy is available for unbalanced atrioventricular (AV) septal defects. If evidence of pulmonary overcirculation is present, management of congestive heart failure (CHF) with digoxin, diuretics, and ACE inhibitors may be indicated. ACE inhibitors may also be indicated for atrioventricular valve (AVV) regurgitation.
Cardiac glycosides
These agents theoretically provide a positive inotropic effect. They are used to treat acute and chronic CHF.
Digoxin (Lanoxin)
Frequently used cardiac glycoside that inhibits the sarcolemmal sodium-potassium ATPase, leading to an increase in intracellular calcium concentration and increased myocardial contractility.
Adult
0.125-0.5 mg/d PO
Pediatric
Preterm infant: 5-7.5 mcg/kg/d PO divided bid
Term infant: 6-10 mcg/kg/d PO divided bid
1 month to 2 years: 10-15 mcg/kg/d PO divided bid
2-5 years: 7.5-10 mcg/kg/d PO divided bid
5-10 years: 5-10 mcg/kg/d PO divided bid
>10 years: 2.5-5 mcg/kg/d PO as a single daily dose
Quinidine, quinine, verapamil, propafenone, diltiazem, erythromycin, itraconazole, indomethacin, and amiodarone increase plasma concentrations
Prokinetic agents (eg, cisapride, metoclopramide), antacids, kaolin-pectin, and resin-binding agents (eg, cholestyramine) can decrease absorption
Coadministration with IV calcium may produce arrhythmias
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, and procarbazine), aluminum or magnesium antacids, rifampin, sucralfate, sulfasalazine, barbiturates, kaolin/pectin, and aminosalicylic acid
Documented hypersensitivity; AV block; idiopathic hypertrophic subaortic stenosis; constrictive pericarditis; hypokalemia; renal failure
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 hypokalemia (monitor serum potassium levels); reduce dose with renal dysfunction; CNS effects (eg, drowsiness) and GI effects (eg, nausea/vomiting) are more common adverse effects; digoxin can cause cardiac arrhythmias; hypokalemia, hypomagnesemia, hypercalcemia, and hypermagnesemia predispose to digoxin toxicity
Loop diuretics
These agents inhibit electrolyte reabsorption in the ascending loop of Henle, thereby promoting diuresis. They are used to treat heart failure or hepatic, renal, or pulmonary disease when sodium and water retention has resulted in edema or ascites.
Furosemide (Lasix)
Increases excretion of water by interfering with chloride-binding cotransport system that inhibits sodium and chloride reabsorption in the ascending loop of Henle and distal tubule.
Adult
20-80 mg/d PO/IV/IM divided q6-12h
Pediatric
1-4 mg/kg/d PO divided q6-24h
1-2 mg/kg/dose IV q6-24h
Increases nephrotoxicity of cephalosporins; ototoxicity can be increased by concomitant use of aminoglycosides; anticoagulant activity of warfarin may be enhanced
Metformin decreases furosemide concentrations; furosemide 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); increased plasma lithium levels and toxicity are possible when lithium is taken concurrently
Documented hypersensitivity; hypokalemia; anuria; renal failure
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
Monitor serum electrolytes; may produce intravascular dehydration, severe hypokalemia, and significant hypochloremic metabolic alkalosis; may produce hyperuricemia; may produce deafness due to rapid injection, high doses, or concurrent administration of other ototoxic agents
ACE inhibitors
ACE inhibitors are beneficial in all stages of chronic heart failure. Pharmacologic effects result in decreased systemic vascular resistance, reducing blood pressure, preload, and afterload.
Captopril (Capoten)
Inhibits activity of ACE, thereby preventing conversion of angiotensin I to angiotensin II (a potent vasoconstrictor). Decreased levels of angiotensin II lead to increased plasma renin levels and decreased aldosterone levels.
Adult
6.25-12.5 mg PO tid; not to exceed 150 mg PO tid
Pediatric
Neonates: 0.05-0.1 mg/kg/dose PO q6-24h; may titrate dose to 0.5 mg/kg/dose
Infants: 0.15-0.3 mg/kg/dose PO q6-24h; may titrate dose, not to exceed 6 mg/kg/d divided bid/tid/qid
Children: 0.3-0.5 mg/kg/dose PO q6-24h; may titrate dose, not to exceed 6 mg/kg/d divided bid/tid/qid
NSAIDs may reduce hypotensive effects of captopril; hypotensive effects may be enhanced when given concurrently with diuretics; rifampin decreases captopril levels; may increase digoxin, lithium, and allopurinol levels
Documented hypersensitivity
Pregnancy
D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus
Precautions
Caution with renal impairment, LV outflow tract obstruction, and valvular stenosis; decrease dose if sodium and water are depleted
Enalapril (Vasotec)
Prevents conversion of angiotensin I to angiotensin II, a potent vasoconstrictor, resulting in increased levels of plasma renin and a reduction in aldosterone secretion.
Helps control blood pressure and proteinuria. Decreases pulmonary-to-systemic flow ratio in the catheterization laboratory and increases systemic blood flow in patients with relatively low pulmonary vascular resistance. Has favorable clinical effect when administered over a long period. Helps prevent potassium loss in distal tubules. The body conserves potassium; thus, less oral potassium supplementation needed.
Patients who develop a cough, angioedema, bronchospasm, or other hypersensitivity reactions after starting ACEIs should be switched to an angiotensin-receptor blocker.
Adult
2.5-5 mg/d PO; increase prn
Dosing range: 10-40 mg/d PO qd or divided bid
Alternatively, 1.25 mg/dose IV over 5 min q6h
Pediatric
0.1-0.3 mg/kg/d PO qd or divided bid
NSAIDs may reduce hypotensive effects of enalapril; ACE inhibitors may increase digoxin, lithium, and allopurinol levels; rifampin decreases enalapril levels; probenecid may increase enalapril levels; the hypotensive effects of ACE inhibitors may be enhanced when given concurrently with diuretics
Documented hypersensitivity
Pregnancy
D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus
Precautions
Caution in renal impairment, valvular stenosis, or severe CHF
More on Atrioventricular Septal Defect, Unbalanced |
| Overview: Atrioventricular Septal Defect, Unbalanced |
| Differential Diagnoses & Workup: Atrioventricular Septal Defect, Unbalanced |
 Treatment & Medication: Atrioventricular Septal Defect, Unbalanced |
| Follow-up: Atrioventricular Septal Defect, Unbalanced |
| Multimedia: Atrioventricular Septal Defect, Unbalanced |
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References
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Journois D, Baufreton C, Mauriat P, et al. Effects of inhaled nitric oxide administration on early postoperative mortality in patients operated for correction of atrioventricular canal defects. Chest. Nov 2005;128(5):3537-44. [Medline].
Emanuel R, Somerville J, Inns A, Withers R. Evidence of congenital heart disease in the offspring of parents with atrioventricular defects. Br Heart J. Feb 1983;49(2):144-7. [Medline].
Apfel HD, Gersony WM. Clinical evaluation, medical management and outcome of atrioventricular canal defects. Prog Pediatr Cardiol. 1999;10:129-36.
Bricker J, McNamara D, Garson A. Defects of the atrial septum including the atrioventricular canal. In: Science and Practice of Pediatric Cardiology. Lippincott Williams & Wilkins;1990:1036-1051.
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Nadas AS. Endocardial cushion defects. In: Flyer DC, ed. Nadas' Pediatric Cardiology. Hanley & Belfus Inc; 1992:577-86.
Further Reading
Keywords
unbalanced atrioventricular septal defect, AVSD, AV canal, AVC, unbalanced endocardial cushion defects, left ventricular–type septal defect, LV-type septal defect, left ventricular–type canal, LV-type canal, left ventricular–dominant AV septal defect, LV-dominant AV septal defect, left ventricular–dominant AV canal, LV-dominant AV canal, atrioventricular canal, atrioventricular septal defect, right ventricular–type septal defect, RV-type septal defect, right ventricular–type canal, RV-type canal, right ventricular–dominant AV septal defect, RV-dominant AV septal defect, right ventricular–dominant AV canal, RV-dominant AV canal, congestive heart failure, pulmonary artery banding, Down syndrome, tachypnea, failure to thrive, pulmonary outflow tract obstruction, coarctation of the aorta, trisomy 21
