AUTHORS 

Jamie Colombo, DO, Assistant Professor of Pediatric Cardiology, University of Arizona, Tucson

Preston J. Boyer, MD, Pediatric Resident, University of Arizona, Tucson

Shelby White, MD, FACC, Assistant Professor of Pediatric Cardiology, University of Virginia, Charlottesville

PEER REVIEWER

Larry B. Mellick, MD, MS, FAAP, FACEP, Vice Chairman for Academic Affairs, Interim Section Chief of Pediatric Emergency Medicine, Assistant Residency Director, Professor of Emergency Medicine, University of South Alabama, Mobile

EXECUTIVE SUMMARY

Critical congential heart disease (CCHD) refers to heart defects present at birth that, when left untreated, can present emergently within the first year of life with a significant risk of mortal­ity without prompt intervention. Two-thirds of these infants will die in the first year without appropriate intervention.

The three most common presentations of CCHD are important to keep in mind: shock, cya­nosis, and respiratory distress.

Shock in the infant can manifest early, with poor feeding and fussiness, and progress to lethargy. The hallmark of shock is hypoperfusion, often present­ing with poor capillary refill and weak pulses. Cardiogenic shock also can have nonspecific signs, such as tachycardia, cyanosis, restlessness, oliguria, bradycardia, or altered mental status, and may overlap with presentations of heart failure with diaphoresis, edema, and hepatomegaly.

Cyanosis related to congential heart disease (CHD) is central in nature, which typically can be observed in the mucous membranes or the trunk. The differential diagnosis for cyanosis in the infant includes persistent pulmonary hypertension, CHD, and primary lung disease; however, cyanosis without respira­tory distress is almost always associated with structural CHD and should prompt a diagnostic workup for cardiac disease. Hypoxia due to lung disease should improve with the administration of oxy­gen, whereas hypoxia that remains despite the use of 100% oxygen could indicate CHD.

Respiratory distress as a result of CHD can be a manifestation of cardiogenic shock in neonates or due to overcircula­tion related to a large left-to-right shunt lesion. Overcirculation typically presents after 6 weeks of age and is a result of excessive pulmonary blood flow.

Infants with coarctation of the aorta typically present in the first two to six weeks of life, and more commonly between days three through seven of life, when the ductus arteriosus begins to close, resulting in the development of aortic arch obstruc­tion and reduced systemic perfusion. As a result, patients can begin to manifest signs of hypoperfusion to the lower body, diaphoresis with feeds, tachypnea, retractions, and cyanosis. Infants who present acutely during this period can have concurrent signs of renal failure, such as oliguria or anuria, mesenteric ischemia, and metabolic acidosis. Common physical findings are a gal­lop and absent, delayed, or weak pulses in the lower extremities. A high blood pres­sure gradient between upper and lower extremities (> 20 mmHg) can be present. Also there can be a disparity between upper and lower extremity pulse oximetry readings.   

Tetralogy of Fallot represents between 3 and 10% of all CHD. Classically, it has been defined by four dis­tinct anomalies: ventricular septal defect, overriding aorta, right ventricular outflow tract obstruction, and right ventricular hypertrophy.  Infants with the most severe right ventricular outflow tract obstruction are dependent on the ductus arteriosus for pulmonary blood flow. They present with profound cyanosis during the first weeks of life as the ductus begins to close. Clubbing, dyspnea, or hypoxic spells also can be present in an older infant or child.

An infant with tetralogy of Fallot may present with periods of intense fussiness and cyanosis, which are typical of hypoxic spells (“tet spell”). These are demonstrated by rapid and deep respira­tions, irritability and prolonged crying, cyanosis (increased from baseline), and decreased intensity of the murmur. Severe spells can lead to seizures, flaccid tone, stroke, or death. Treatment starts with calming the child by relieving pain or anxiety. Increase sys­temic vascular resistance and reduce the right-to-left shunting by holding the infant in a knee-chest position to increase the intraabdomi­nal pressure.  Morphine, which can be administered intramuscularly or subcutaneously, and midazolam, which can be given intranasally, can help the child remain calm and help suppress the respiratory center to reverse the right-to-left shunting.  Volume can be infused to optimize preload. In severe hypoxic spells with acidosis, treatment with sodium bicar­bonate, ketamine, or propranolol also may be helpful. 

Early initiation of prostaglandin E1 (PGE) is important in the course of CCHD or tetralogy of Fallot with severe pulmonary stenosis or pulmonary atresia because many CHD cases that present in the first two to four weeks of life are depen­dent on the ductus arteriosus. The most common risks of PGE include apnea and hypotension, so the infant should be monitored closely to observe for any hypercapnia or hypoxia.