Medication Summary
Medications used in the management of ventricular septal defects (VSDs) associated with evidence of left ventricular volume overload include diuretics, angiotensin-converting enzyme (ACE) inhibitors, and cardiac glycosides.
Diuretics, Loop
Class Summary
Diuretics promote the excretion of water and electrolytes by the kidneys. They are used in the treatment of hypertension; heart failure; and hepatic, renal, or pulmonary disease when salt and water retention has resulted in edema or ascites.
Furosemide (Lasix)
Furosemide increases excretion of water by interfering with the chloride-binding cotransport system, which inhibits sodium and chloride reabsorption in the ascending loop of Henle and the distal renal tubule. Dosing must be individualized. Depending on the response, administer furosemide in increments of 20-40 mg no sooner than 6-8 hours after the previous dose until the desired diuresis occurs. In infants, titrate in increments of 1 mg/kg until a satisfactory effect is achieved.
ACE Inhibitors
Class Summary
ACE inhibitors are used to treat congestive heart failure (CHF). They may be of use to treat systemic afterload.
Captopril
Captopril prevents conversion of angiotensin I to angiotensin II, a potent vasoconstrictor, lowering aldosterone secretion. It can be useful in reducing systemic afterload.
Enalapril (Vasotec)
Enalapril is considered a reasonable first drug of choice in this group because of its increased dosing interval (q12-24h). A competitive ACE inhibitor, it reduces angiotensin II levels, decreasing aldosterone secretion. Enalapril is available in a liquid suspension.
Lisinopril (Prinivil, Zestril)
Lisinopril is considered a reasonable first drug of choice in this group because of its increased dosing interval (q12-24h). It prevents the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor, resulting in lower aldosterone secretion.
Inotropic Agents
Class Summary
Cardiac glycosides possess positive inotropic activity, which is mediated by inhibition of sodium-potassium adenosine triphosphatase (ATPase). The also reduce conductivity in the heart, particularly through the atrioventricular (AV) node; therefore, they have a negative chronotropic effect. Cardiac glycosides have similar pharmacologic effects but differ considerably in their speed of onset and duration of action. These agents are used to slow the heart rate in supraventricular arrhythmias, especially atrial fibrillation. They are also administered in chronic heart failure.
Digoxin (Lanoxin)
Digoxin is a cardiac glycoside with direct inotropic effects, in addition to indirect effects on the cardiovascular system. It acts directly on cardiac muscle, increasing myocardial systolic contractions. Its indirect actions increase the activity of the carotid sinus nerve and enhance sympathetic withdrawal for any given increase in mean arterial pressure.
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Ventricular Septal Defects. A: Image shows a ventricular septum viewed from the right side. It has the following four components: inlet septum from the tricuspid annulus to the attachments of the tricuspid valve (I); trabecular septum from inlet to apex and up to the smooth-walled outlet (T); outlet septum, which extends to the pulmonary valve (O); and membranous septum. B: Anatomic positions of the defects are as follows: outlet defect (a); papillary muscle of the conus (b); perimembranous defect (c); marginal muscular defects (d); central muscular defects (e); inlet defect (f); and apical muscular defects (g).
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Ventricular Septal Defects. Schematic representation of the location of various types of ventricular septal defects (VSDs) from the right ventricular aspect. A = Doubly committed subarterial ventricular septal defect; B = Perimembranous ventricular septal defect; C = Inlet or atrioventricular canal-type ventricular septal defect; D = Muscular ventricular septal defect.
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Ventricular Septal Defects. Supracristal ventricular septal defect (VSD) on computed tomography scanning. Top image: Parasternal long-axis view shows the defect just below the aortic root. Middle image: The plane of sound is tilted to view the right ventricular (RV) outflow tract, and the defect is observed below the pulmonic valve. Bottom image: Parasternal short-axis view shows the ventricular septal defect between the aortic root (Ao) and the pulmonic valve (PV). LA = left atrium; LV = left ventricle; PA = pulmonary artery; RA = right atrium.
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Ventricular Septal Defects. Echocardiogram from a child with a perimembranous ventricular septal defect (VSD). Note the defect at the 10 o'clock position in the parasternal short-axis view. AO = aortic root; LA = left atrium; LV = left ventricle; PA = pulmonary artery; RA = right atrium; RV = right ventricle.
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Ventricular Septal Defects. Apical four-chamber views on computed tomography scanning. A: Image shows a large inlet defect. The defect is posterior and at the level of the atrioventricular valves. B: Image shows a small midmuscular ventricular septal defect. LA = left atrium; LV = left ventricle; PA = pulmonary artery; RA = right atrium; RV = right ventricle.