AUTHOR AND EDITOR INFORMATION

Section 1 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

INTRODUCTION

Section 2 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Background

The term coronary artery anomaly refers to a wide range of congenital abnormalities involving the origin, course, and structure of epicardial coronary arteries. By definition, these abnormalities occur in less than 1% of the general population. Coronary artery anomalies are frequently found in association with other major congenital cardiac defects. This article, however, is focused on isolated coronary artery anomalies (ie, in the absence of other major congenital cardiac defects). In adults, the clinical interest in coronary anomalies relates to their occasional association with sudden death, myocardial ischemia, congestive heart failure, or endocarditis. In addition, presence of coronary artery anomalies may, at times, create challenges during coronary angiography, percutaneous coronary interventions, and coronary artery surgery.

Pathophysiology

Normal coronary artery anatomy

The coronary arteries are the only branches of the ascending aorta, and they supply blood to all structures within the pericardial cavity. Usually, the 2 coronary artery ostia are located in the center of the left and right (anterior) sinuses of the aortic valve. The posterior sinus of the aortic valve contains no coronary ostium and is often designated as the noncoronary sinus.

Left coronary artery

The left coronary artery originates from the left coronary sinus of the aorta, and, after a single initial trunk (left main coronary artery) of variable length and size, it gives rise to the left anterior descending (LAD) and left circumflex (LCx) coronary artery branches. The LAD coronary artery runs along the anterior interventricular sulcus, provides several superficial (diagonal) and multiple deep (septal perforator) branches, and usually reaches the cardiac apex. In some individuals, a diagonal branch may have a very proximal takeoff such that the left main (LM) gives rise to 3 instead of 2 branches. In this case, the additional artery arising from the LM originates in between the LAD and the LCx coronary arteries and is called the ramus intermedius coronary artery. This artery provides blood supply to the anterior left ventricular free wall.

The LCx coronary artery runs in the left atrioventricular groove and usually has 1 or more branches that reach the obtuse margin of the heart (obtuse marginals). The LAD coronary artery supplies blood to the anterior left ventricular wall through its diagonal branches, the anterior two thirds of the interventricular septum through its septal perforator branches, and commonly the cardiac apex by its terminal branches. The LCx coronary artery supplies blood to the left ventricular lateral and posterior walls through its obtuse marginal branches.

Right coronary artery

The right coronary artery (RCA) originates from the right coronary sinus of the aorta and runs in the right atrioventricular groove to reach the crux (junction of the atrioventricular groove and the posterior interventricular sulcus) of the heart. It supplies blood to the inferior (diaphragmatic) left ventricular wall and often the posterior one third of the interventricular septum as well as the free wall of the right ventricular through its right ventricular (acute marginal) branches. The posterior descending branch of the RCA supplies blood to the posterior one third of the interventricular septum. A posterolateral branch of the RCA provides blood supply to the basal most portion of the posterolateral left ventricular wall.

Arterial dominance

Left or right coronary artery dominance is determined by the origin of the atrioventricular nodal artery at the crux of the heart (see above). The atrioventricular node artery originates from the RCA in approximately 90% of the population and LCx coronary artery in the remaining 10%. The dominant coronary artery also gives off the posterior descending coronary artery that runs in the posterior interventricular sulcus and provides septal perforator branches to the posterior one third of the interventricular septum. In some individuals, both the RCA and the LCx reach the crux and jointly give rise to the posterior descending coronary artery. In such cases, the coronary arterial system is referred to as codominant.

Variations in normal coronary artery anatomy (See Media file 1)

Absence of the left main coronary artery with separate origin of the LAD and LCx coronary arteries from the left coronary sinus of the aorta has been described in roughly 1% of patients undergoing angiography and is considered a normal variant. In addition, one or more infundibular (conal) arteries may arise from separate ostia in the aorta. As many as 5 separate conal artery ostia have been reported in otherwise normal hearts. Minor variations in the location of ostia within the coronary sinuses of the aorta are observed frequently and are of no clinical significance.

Anomalous coronary arteries

The following table presents a classification of major isolated coronary artery anomalies. As seen, coronary artery anomalies may involve abnormalities of number, origin and/or course, termination, or structure of the epicardial coronary arteries.

Abnormal number

In some individuals, certain left ventricular territories may be supplied by more than one coronary artery. Duplications of the LAD coronary artery, LCx coronary artery, and RCA have been reported.

• Dual LAD coronary artery consists of one short and another long artery and has been classified into 4 different subtypes.
• • In the most common form (type I), the short and long LAD coronary arteries originate from the normal LAD coronary artery proper. The shorter artery then runs in the anterior interventricular sulcus and terminates abruptly long before reaching the apex. The longer artery, however, runs on the anterior epicardial surface of the left ventricle and returns to the anterior interventricular sulcus in its distal one third and then continues on to the apex. All diagonal branches originate from the longer artery.
  • In the type II variety, the long LAD coronary artery courses over the anterior surface of the right rather than the left ventricle.
  • In the type III dual LAD coronary artery, the long artery has, at least partly, an intramyocardial (bridging) course. Unlike types I and II, the septal perforators arise from the long LAD and the diagonals arise from the short LAD coronary artery.
  • Finally, in the type IV variety, the short LAD coronary artery arises from the LM coronary artery and the long artery anomalously arises from the RCA and courses to the left side anterior to the right ventricular outflow tract.
• Duplications of the RCA have been reported with both single and double ostium in the right coronary sinus. The duplicate vessels may course together in the right atrioventricular groove and/or have separate courses with one coursing on the epicardial surface of the right ventricle. Both vessels give rise to right ventricular branches and generally 1 of the 2 gives off the posterior descending coronary artery.
• We have recently reported duplication of the LCx, or otherwise described as aberrant origin of one OM branch from the LAD, ramus intermedius, or diagonal branch of the LAD, in a case series of 24 patients (See Media file 2). In this instance, the anomalous OM courses parallel to the LCx coronary artery and supplies blood to the acute margin of the left ventricle.

Anomalous origin (see Media files 3-5)

Abnormalities of the origin of coronary arteries with subsequent normal epicardial course relate to the anomalous location of one or both coronary ostia. These include the origin of LM, LAD, LCx, or RCA from the pulmonary trunk. In addition, coronary arteries may originate directly from the left or right ventricles; the bronchial, internal mammary, subclavian, right carotid, or innominate arteries; the aortic arch; or the descending thoracic aorta. High takeoff of the left or right coronary ostia, defined as the location of the ostium of the left or right coronary artery more than 1 cm above the sinotubular junction, has been described.

Anomalous origin and course

Single coronary artery

• The entire coronary artery system may originate from a single ostium (solitary coronary ostium or single coronary artery) in the aorta. This solitary ostium is either located in the left or right coronary sinus of the aorta. When the LM coronary artery originates from the proximal RCA, or vice versa, the anomalous artery takes 1 of 4 aberrant pathways to reach its proper vascular territory. These pathways are designated as type A (Anterior to the right ventricular outflow tract), type B (Between the aorta and pulmonary trunk), type C (Cristal, coursing through the crista supraventricularis portion of the septum), and type D (Dorsal or posterior to the aorta).
• Single coronary arteries may also include the separate origin of the LAD and LCx coronary arteries from the proximal RCA. In this case, the LAD coronary artery takes one of the type A, B, or C pathways, and the LCx coronary artery takes either the B or D pathway. The LCx coronary artery may also originate from the distal RCA. In that case, the LCx coronary artery is merely a continuation of the RCA in the posterior atrioventricular groove. Overall, a total of 20 possible variations of single coronary artery have been described.

Origin from opposite coronary sinus

• Both the left and right coronary arteries may arise from separate ostia located in the same, either left or right, sinus of the aorta. In such cases, the anomalous vessels take 1 of the 4 possible courses to reach their proper territories similar to what was described above for the single coronary artery (types A-D).

Anomalous course

Otherwise normal coronary arteries may have an intramyocardial course (ie, myocardial bridge). This particular abnormality involves a variable length of the vessel and is observed most commonly in the proximal portion of the LAD coronary artery.

Anomalous termination (see Media file 6)

Major epicardial coronary arteries may terminate abnormally into one of the cardiac chambers, the coronary sinus, or the pulmonary trunk and, thus, produce fistulas. These fistulas can originate from the left coronary artery system (50-60%), right coronary artery system (30-40%), or both (2-5%). Most fistulas (90%) drain into the right heart.

Abnormal coronary structure

Both congenital stenosis and atresia of the coronary arteries have been described. Congenital epicardial coronary artery stenosis is usually caused by a membrane or a fibrotic ridge. Coronary artery atresia is characterized by the presence of an ostial dimple in the left or right aortic sinus that terminates in a cordlike fibrotic structure without a patent lumen. Atresia may also involve individual major epicardial coronary arteries. Hypoplastic coronary arteries have small luminal diameter (usually <1 mm) and reduced length. The latter is often associated with the absence of the posterior descending coronary artery.

Frequency

United States

Coronary artery anomalies are observed in 0.3-1.3% of patients undergoing diagnostic coronary angiography, in approximately 1% of routine autopsy examinations, and in 4-15% of young people who experience sudden death. In the general population, the incidence of a single coronary artery is approximately 0.024%, while coronary artery fistulas are found in 0.2% of patients undergoing coronary angiography. Coronary artery fistulas are present in 0.002% of all patients with congenital heart disease. Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is reported in 0.0003% of the general population. This anomaly is responsible for 18% of all cases of congestive heart failure in children younger than 2 years.

Mortality/Morbidity

Most coronary artery anomalies are clinically silent and do not affect the quality of life or lifespan of the affected individuals. Specific forms of anomaly, such as the origin of the left main coronary artery from the pulmonary trunk, the aberrant course of the arteries between the great vessels in association with anomalous and slitlike ostium, and large coronary artery fistulas, may be associated with sudden death, myocardial ischemia, congestive heart failure, or endocarditis. Hypoplastic coronary arteries and high take-off of coronary ostia have been occasionally reported to have been associated with sudden death. The exact incidence of these associated clinical events is not known.

Sex

No differences have been reported in incidence of specific coronary artery anomalies among male and female subjects.

Age

• Origin of left main coronary artery from the pulmonary trunk manifests during early infancy.
• Other significant coronary anomalies usually result in symptoms during young adult life.
• The remaining anomalies generally are clinically silent and may be discovered incidentally during noninvasive or invasive diagnostic testing for unrelated symptoms.

CLINICAL

Section 3 of 11  

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• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

History

• Most patients with coronary artery anomaly remain asymptomatic either because the anomaly does not produce any symptoms during life or because the first manifestation is sudden death.
• In infants, myocardial ischemia may manifest as episodic crying, tachypnea, or wheezing. The infant may refuse to eat, presumably in order to avoid anginal pain.
• In older individuals, symptoms are reported in less than 30% of patients before a diagnosis of coronary anomaly is made. These generally include palpitation, exertional dyspnea, angina or syncope, fatigue, or fever. These symptoms rarely raise clinical suspicion for diagnosis of coronary artery anomalies.

Physical

Most coronary artery anomalies are discovered incidentally during noninvasive imaging, coronary angiography, or at autopsy and cause no clinical symptoms. However, particular subsets of these anomalies have been associated with sudden death, myocardial ischemia, congestive heart failure, or bacterial endocarditis.

• Sudden death
• • This presentation has been observed in association with the origin of the left main or right coronary arteries from the opposite sinus of Valsalva and the type B (ie, between the aorta and pulmonary trunk) course of the anomalous vessel. This particular anomaly often is associated with a slitlike ostium and an obtuse takeoff of the proximal portion of the aberrant coronary artery. This combination may result in ischemia during exertion due to the stretching of the affected vessel that compromises blood flow at the ostium of the vessel. Increased cardiac output during exercise may also distend the ascending aorta and the pulmonary trunk and contribute to decreased blood flow through the anomalous coronary artery.
  • Sudden death also has been reported with congenital coronary artery structural abnormalities such as stenosis, hypoplasia, or atresia. Such structural abnormalities of the coronary arteries interfere with normal myocardial perfusion. Sudden death also has been reported in association with high takeoff of coronary arteries. The latter may lead to impairment of diastolic coronary artery flow. Ventricular fibrillation has been identified as the terminal event in some patients with coronary artery anomaly who have died suddenly during ambulatory electrocardiographic monitoring.
• Myocardial ischemia
• • In addition to abnormalities mentioned under sudden death, myocardial ischemia also may occur in patients with anomalous origin of the left and, occasionally, right coronary artery from the pulmonary artery or right ventricle. In this type of anomaly, myocardial ischemia primarily occurs because of low coronary perfusion pressure secondary to the relatively low pulmonary diastolic pressure.
  • Myocardial ischemia also may occur in the setting of a single coronary artery when the aberrantly coursing vessel terminates prematurely and the myocardium distal to the vessel is inadequately perfused.
  • Intramyocardial course of coronary arteries (ie, myocardial bridge) occasionally has been associated with myocardial ischemia. The mechanism of myocardial ischemia in this condition is not fully elucidated.
  • Large coronary artery fistulas also may reduce myocardial perfusion and, thus, cause ischemia.
• Congestive heart failure
• • Large coronary artery fistulas may result in right- or left-sided cardiac volume overload with or without symptoms of congestive heart failure. The hemodynamic effects of coronary artery fistulas depend on their site of drainage, diameter, and length. Drainage into the right heart produces left-to-right shunt with dilation of the right heart chambers and increase in pulmonary resistance. Eisenmenger syndrome has not been reported in association with such shunts. Drainage into the left heart produces left ventricular volume overload that may mimic aortic insufficiency clinically.
  • Heart failure also may be the predominant presentation in infants with the origin of the left main coronary artery from the pulmonary trunk. In the latter condition, the left ventricle appears dilated and globally hypokinetic on transthoracic echocardiography.
• Bacterial endocarditis: Coronary artery fistulas may result in an increased risk of infective endocarditis or endarteritis depending on the location of the fistula. The infection commonly involves the receiving chamber of the heart at the entrance site of the anomalous coronary artery.
• Physical findings generally are absent in most congenital coronary artery anomalies. The following signs may be present in patients with either anomalous origin of the left coronary artery from the pulmonary artery or a large coronary artery fistula:
• • Tachypnea and respiratory distress
  • Continuous precordial murmur
  • Systolic murmur of mitral regurgitation
  • S₃ or S₄ gallop rhythms
  • Cardiomegaly
  • Hepatomegaly
  • Edema
  • Peripheral cyanosis
  • Failure to thrive (infants)

Causes

The exact pathogenetic mechanisms for development of congenital coronary artery anomalies are not well understood. According to extensive embryologic studies, formation of a normal coronary arterial system depends on multiple morphologic features, including formation of cardiac sinusoids, development of coronary buds on embryologic aortopulmonary trunk, and selective connection between the 2 systems. Any malformation within these systems may lead to development of coronary artery anomalies.

• Some congenital heart diseases are found in association with coronary artery anomalies. These associations are especially strong in the following:
• • Truncus arteriosus, single coronary artery, and anterior coronary trunk crossing the outflow tract of the right ventricle
  • Transposition of the great arteries and ectopic origin of coronary ostia
  • Pulmonary valve atresia with intact ventricular septum and solitary coronary artery or coronary artery fistula draining into the right ventricle
  • Double outlet right ventricle and unpredictable coronary anatomy
  • Isolated aortic valve anomalies (such as bicuspid aortic valve) and ectopic origin of ostia, left coronary artery dominance, high takeoff of the left coronary artery, and shortening of the left main trunk
  • Tetralogy of Fallot and ectopic origin of the coronary arteries or coronary artery fistula draining into the pulmonary trunk
• Familial clustering: Isolated reports of specific coronary artery anomalies occurring in family members have appeared in recent years. However, to date, no definitive data on coronary inheritance pattern have been reported in humans.

DIFFERENTIALS

Section 4 of 11  

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Other Problems to be Considered

Arrhythmogenic right ventricular dysplasia
Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA)
Sudden death

WORKUP

Section 5 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Imaging Studies

For initial screening purposes, preferred imaging modalities should (1) be noninvasive; (2) be applicable to a wide population, at a reasonable cost, with a minimal level of side effects such as those that could be involved in the use of ionizing radiation; and (3) have reliable diagnostic accuracy.

Noninvasive imaging modalities in patients with coronary artery anomaly are used to either visualize the anomalous vessels or evaluate a heart murmur or symptoms of dyspnea, angina, syncope, or endocarditis. Visualization of anomalous coronary arteries can be achieved by the following noninvasive methods:
 
Transthoracic and transesophageal echocardiography
 
Echocardiography is an attractive screening option in view of its relative simplicity, noninvasiveness, lack of ionizing radiation, relatively low cost, and widespread availability. However, the discriminating power of echocardiography is intrinsically limited (both temporally and geometrically), and few opportunities are available for aligning the echocardiographic imaging planes with the coronary anatomy, which presents curves and phasic movements. Therefore, this technology is less than ideal for firmly diagnosing most types of coronary artery anomalies in adults.   
 
Computed tomographic angiography (CT angio)
 
For studying coronary artery anomalies, CT angio has seen a dramatic rise in interest since the introduction of multidetector computed tomography (MDCT) scanners with 4 detector rows in 1998. The earliest reports on coronary artery anomalies were based on experience with electron-beam computed tomographic (EBCT) scanning, which correlated closely with coronary angiography.

Initial reports concerning the use of MDCT for identifying and characterizing anomalies of coronary origin and course have been quite encouraging, especially considering the benefits of 3-dimensional image reconstruction. Multiple MDCT studies of coronary artery anomalies have already been performed, including studies done to correlate noninvasive findings with that of invasive coronary angiography. Rapid advances in CT angio technology has made this imaging modality a reliable means of defining coronary artery anomalies. However, routine use of CT angio in young patients with suspected coronary anomaly should be discouraged due to exposure to relatively high doses of ionizing radiation. The importance of interpretation skills and proper training in accurate diagnosis of coronary artery anomalies by this modality should be emphasized.
 
Coronary magnetic resonance angiography (MRA)
 
MRA is a noninvasive technique without the disadvantages of CT angio, including ionizing radiation and nephrotoxic contrast agent. As a tomographic imaging technique, MRA allows 3-dimensional reconstruction and omnidirectional visualization of a coronary artery origin and course. In several published series, MRA has been shown to be as accurate as coronary angiography in defining the origin and proximal course of the coronary arteries. However, high resolution definition of the more distal portions of anomalous coronary arteries may be problematic in some patients. Although generally considered safe, MRA is not free of limitations including its inability to be used in patients with claustrophobia or in those with certain metallic implanted devices. Gadolinium-based MR contrast agents have also been implicated in several instances of nephrogenic systemic sclerosis, particularly in patients with advanced kidney disease. 

This modality of imaging is, however, the preferred diagnostic test in younger patients in whom echocardiography has failed to provide adequate definition of the coronary artery anatomy. 
 
Invasive coronary angiography

Definitive diagnosis of coronary artery anomalies at times requires selective arterial angiography via catheterization.

• During coronary angiography, placing a pulmonary artery flotation (Swan-Ganz) catheter to guide assessment of the course of the anomalous vessels is recommended.
• Origin of coronary artery from pulmonary trunk may require pulmonary angiography; however, most arteries are visualized during selective arteriography of vessels originating from the aorta.

Other Tests

• Electrocardiogram (ECG) for evaluation of myocardial ischemia
• Congenital coronary artery anomalies associated with the origin of the left main or right coronary arteries from the opposite sinus of Valsalva and the type B (ie, between the aorta and pulmonary trunk) course of the anomalous vessel are of particular concern in young competitive athletes. Standard testing with ECG under resting or exercise conditions is unlikely to provide clinical evidence of myocardial ischemia and is not a reliable screening test in athletes. Premonitory cardiac symptoms may occur shortly before sudden death (typically associated with anomalous left main coronary artery), suggesting that a history of exertional syncope or chest pain requires exclusion of this anomaly.
• Nuclear myocardial perfusion studies using exercise and single-photon emission computed tomography (SPECT) in association with thallium or technetium-based radiolabeled agents can demonstrate ischemia within the myocardial territory supplied by the anomalous coronary artery. Coronary angiography is then recommended to define coronary anatomy.
• Intracoronary ultrasonography: This invasive study allows evaluation of the mural structure of anomalous coronary arteries in patients in whom invasive coronary angiography fails to clearly demonstrate degree of luminal narrowing or its physiologic significance.

TREATMENT

Section 6 of 11  

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• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Medical Care

The goal of medical therapy is to improve and preserve the hemodynamic status through acting on myocardial contractility, reducing congestion, and decreasing myocardial energy expenditure.

• Cardiac glycosides are a mainstay of inotropic therapy in those patients with congestive heart failure. Digoxin improves cardiac function because of its positive inotropic effect and negative chronotropic effect, but it must be used with caution in patients with myocardial ischemia.
• Dobutamine (primarily a beta1-adrenergic agonist) is particularly useful for treatment of congestive heart failure in children because of its limited effect on heart rate and peripheral vasculature.
• Phosphodiesterase inhibitors (ie, inamrinone, milrinone) can be used as alternatives to dobutamine because of their inotropic effect on the heart and the peripheral vasodilation that reduces the afterload. However, they should be avoided in patients with anomalous origin of a coronary artery from the pulmonary trunk because of the unpredictable vasodilatory effect of these agents on the pulmonary arterial system.
• Loop diuretics (ie, furosemide) may be used in the presence of congestive heart failure.
• Antibiotic prophylaxis for endocarditis is recommended for coronary artery fistulas.
• Beta-adrenergic blocking agents have been used in isolated cases of symptomatic coronary artery anomaly to reduce myocardial oxygen demand and, thus, prevent ischemia.

Surgical Care

Surgery is the only definitive treatment for coronary artery anomalies.

• Coronary arteries originating from the pulmonary trunk are resected optimally from the pulmonary trunk and reimplanted into the ascending aorta. Alternative methods of revascularization include bypass grafts using the internal mammary artery or saphenous veins. In some patients with the origin of the coronary artery from the pulmonary trunk, an intrapulmonary tunnel may be produced to connect the ostium of the anomalous artery to the aorta.
• Coronary artery fistulas can be treated with percutaneous transcatheter occlusion using a detachable balloon, detachable coils, double-umbrella devices, and microparticles of polyvinyl alcohol foam, or they can be treated surgically with a simple ligation. When possible, ligation is performed preferably at the point of entry of the coronary artery to the cardiac chamber. When this is not possible, ligation is performed internally. In patients with multiple lateral communications between the coronary artery and the cardiac chambers, a tangential arteriorrhaphy can be performed. The great risk in coronary ligation is postsurgical myocardial ischemia or infarction.
• Coronary angioplasty with placement of stent is the treatment of choice for myocardial bridges if convincing evidence of myocardial ischemia exists. However, the vast majority of myocardial bridges do not appear to cause myocardial ischemia.
• Coronary artery bypass grafting, preferably using the internal mammary artery, is the surgical treatment of choice for coronary artery atresia.

Consultations

• Pediatric or adult cardiologist
• Cardiothoracic surgeon

Activity

Discourage heavy exercise and competitive sports in patients with significant coronary artery anomalies at least until surgical correction is performed.

MEDICATION

Section 7 of 11  

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• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

The goals of pharmacotherapy are to reduce morbidity and to prevent complications.

Drug Category: Cardiovascular agents

Used to improve and preserve hemodynamic status by acting on myocardial contractility, reducing congestion, and decreasing myocardial energy expenditure.

Drug Name	Dobutamine (Dobutrex)
Description	Produces vasodilation and increases inotropic state. At higher dosages may cause increased heart rate, exacerbating myocardial ischemia.
Adult Dose	0.5 mcg/kg/min IV initially; titrate to desired therapeutic effect
Pediatric Dose	Administer as in adults
Contraindications	Documented hypersensitivity; idiopathic hypertrophic subaortic stenosis; atrial fibrillation or flutter
Interactions	Beta-adrenergic blockers antagonize effects of dobutamine; general anesthetics may increase toxicity
Pregnancy	B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions	Following MI, use with extreme caution; hypovolemic state should be corrected before using this drug

Drug Name	Inamrinone (Inocor)
Description	Formerly amrinone. Bi-pyridine positive inotrope and vasodilator with little chronotropic activity. Different in mode of action from both digitalis glycosides and catecholamines. More likely to cause tachycardia than dobutamine. May exacerbate myocardial ischemia. Adjust dose according to patient response.
Adult Dose	0.75 mg/kg IV bolus slowly over 2-3 min; maintenance infusion is 5-10 mcg/kg/min; not to exceed 10 mg/kg
Pediatric Dose	Administer as in adults
Contraindications	Documented hypersensitivity
Interactions	Coadministration with diuretics may result in hypovolemia and decrease in filling pressure; cardiac glycosides have additive effects on inamrinone
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	Discontinue therapy if symptoms of liver toxicity develop; correct hypokalemic states before administering therapy

Drug Name	Milrinone (Primacor)
Description	Bi-pyridine positive inotrope and vasodilator with little chronotropic activity. Different in mode of action from both digitalis glycosides and catecholamines.
Adult Dose	50 mcg/kg IV loading dose over 10 min followed by continuous infusion at 0.375-0.75 mcg/kg/min
Pediatric Dose	Administer as in adults; although used as DOC in many pediatric intensive care units, safety and efficacy not well established
Contraindications	Documented hypersensitivity
Interactions	Milrinone precipitates in presence of furosemide
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 fluids, electrolyte changes, and renal function during therapy; excessive diuresis may increase potassium loss and predispose digitalized patients to arrhythmias; important to correct hypokalemia with potassium supplementation prior to treatment; patients showing excessive decreases in blood pressure should have infusion rates slowed or stopped; previous vigorous diuretic therapy has caused significant decreases in cardiac filling pressure; cautiously administer milrinone and monitor blood pressure, heart rate, and clinical symptomatology

Drug Name	Metoprolol (Lopressor)
Description	Selective beta1-adrenergic receptor blocker that decreases automaticity of contractions.
Adult Dose	100 mg/d PO or divided bid/tid initial; increase at 1-wk interval prn to a total of 450 mg/d if necessary
Pediatric Dose	1-5 mg/kg/d PO divided bid
Contraindications	Documented hypersensitivity; uncompensated congestive heart failure; bradycardia; asthma; cardiogenic shock; AV conduction abnormalities
Interactions	Aluminum salts, barbiturates, NSAIDs, penicillins, calcium salts, cholestyramine, and rifampin may decrease bioavailability and plasma levels of metoprolol, possibly resulting in decreased pharmacologic effects; toxicity of metoprolol may increase with coadministration of sparfloxacin, phenothiazines, astemizole, calcium channel blockers, quinidine, flecainide, and contraceptives; metoprolol may increase toxicity of digoxin, flecainide, clonidine, epinephrine, nifedipine, prazosin, verapamil, and lidocaine
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 D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus
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; during an IV, carefully monitor BP, heart rate, and ECG

Drug Name	Atenolol (Tenormin)
Description	Selectively blocks beta1 receptors with little or no effect on beta2 types.
Adult Dose	50 mg/d PO; increase to 100 mg/d prn
Pediatric Dose	1-2 mg/kg/dose PO qd
Contraindications	Documented hypersensitivity; congestive heart failure; pulmonary edema; cardiogenic shock; AV conduction abnormalities; heart block (without a pacemaker)
Interactions	Coadministration with aluminum salts, barbiturates, calcium salts, cholestyramine, NSAIDs, penicillins, and rifampin may decrease effects; haloperidol, hydralazine, loop diuretics, and MAOIs may increase toxicity of atenolol
Pregnancy	D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus
Precautions	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

Drug Name	Propranolol (Inderal, Betachron E-R)
Description	Nonselective, beta-adrenergic receptor blocker with membrane-stabilizing activity that decreases automaticity of contractions. Allow time for drug to reach site of action (particularly if circulation is slow). Do not continue doses after desired alteration in rate or rhythm is achieved.
Adult Dose	1-3 mg IV (under careful monitoring); not to exceed 1 mg/min to avoid lowering blood pressure and causing cardiac standstill; administer second dose after 2 min prn; thereafter, do not administer additional drug in <4 h; switch to PO ASAP; 10-30 mg PO tid/qid
Pediatric Dose	2-4 mg/kg/d PO divided bid (ie, 1-2 mg/kg bid) IV use is not recommended; however, for arrhythmias, 0.01-0.1 mg/kg slow push has been recommended; not to exceed 1 mg/dose; change to PO ASAP
Contraindications	Documented hypersensitivity; uncompensated congestive heart failure; bradycardia; cardiogenic shock; AV conduction abnormalities
Interactions	Coadministration with aluminum salts, barbiturates, NSAIDs, penicillins, calcium salts, cholestyramine, and rifampin may decrease propranolol effects; calcium channel blockers, cimetidine, loop diuretics, and MAOIs may increase toxicity of propranolol; toxicity of hydralazine, haloperidol, benzodiazepines, and phenothiazines may increase with propranolol
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	Beta-adrenergic blockade may decrease signs of acute hypoglycemia and hyperthyroidism; abrupt withdrawal may exacerbate symptoms of hyperthyroidism, including thyroid storm; withdraw drug slowly and monitor closely

Drug Category: Diuretics

Loop diuretics decrease plasma volume and edema by causing diuresis. The reduction in plasma volume and stroke volume associated with diuresis decreases cardiac output and, consequently, blood pressure. May improve pulmonary and systemic cardiovascular activity. Should be used cautiously because any drop in intravascular volume may cause a corresponding drop in cardiac output.

FOLLOW-UP

Section 8 of 11  

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• Differentials
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• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Deterrence/Prevention

Antibiotic prophylaxis for endocarditis is recommended in the presence of fistulas.

Complications

The following complications are associated with certain types of congenital coronary anomalies:

• Sudden cardiac death
• Myocardial ischemia, including acute myocardial infarction
• Congestive heart failure
• Endocarditis

Prognosis

• Most coronary artery anomalies are clinically silent and do not affect the outcome of patients.
• Certain anomalies are associated with sudden death, myocardial ischemia, congestive heart failure, or endocarditis at an early age.

Patient Education

• Patients with coronary anomalies and symptoms of myocardial ischemia or congestive heart failure should avoid strenuous physical activity.
• Antibiotic prophylaxis is recommended in patients with fistulas.

MISCELLANEOUS

Section 9 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Medical/Legal Pitfalls

Coronary artery anomalies may result in sudden death in high-profile athletes. Awareness of such an association may prevent unnecessary litigation.

MULTIMEDIA

Section 10 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Media file 1:  Coronary angiography showing separate origin of the left anterior descending (LAD) and left circumflex (LCx) coronary arteries from the left coronary sinus of the aorta (absent left main).
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Media file 2:  Coronary angiography showing the anomalous origin of the left main (LM) coronary artery from proximal right coronary artery (RCA) with subsequent retroaortic (dorsal [type D]) course to the left side.
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Media type:  Image

Media file 3:  Selective left coronary artery angiogram demonstrating anomalous origin of obtuse marginal (OM) coronary artery from proximal left anterior descending (LAD) coronary artery. LM=left main, LCx=left circumflex.
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Media type:  Image

Media file 4:  Coronary angiography showing the anomalous origin of the right coronary artery (RCA) from the left anterior descending (LAD) coronary artery with subsequent anterior course (anterior [type A]) to the right atrioventricular groove.
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Media type:  Image

Media file 5:  Coronary angiography showing the origin of the right coronary artery (RCA) as the continuation of the left circumflex (LCx) coronary artery.
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Media type:  Image

Media file 6:  Coronary angiography showing the presence of a fistula originating from a diagonal (diag) branch of the left anterior descending coronary artery with anomalous communication with the pulmonary artery (PA).
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Media type:  Image

REFERENCES

Section 11 of 11

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

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Article Last Updated: Mar 13, 2008