Tricuspid Atresia

KEY FEATURES

ESSENTIALS OF DIAGNOSIS

• History of either cyanosis (70%) or congestive heart failure (30%)

• Cyanotic patient with absent right ventricular impulse and prominent left ventricular impulse

• Oligemic lung fields, right atrial and left ventricular prominence without right ventricular enlargement in retrosternal air space on chest radiograph

• Evidence of left ventricular hypertrophy, absent or atretic tricuspid valve, atrial septal defect (ASD), small right ventricle

GENERAL CONSIDERATIONS

• Includes a spectrum of morphologic tricuspid valve abnormalities

• Survival requires the presence of an interatrial communication, such as a patent foramen ovale or ASD

• Other associated cardiac defects:

  • – Ventricular septal defects (VSDs) may result in right ventricular outflow tract obstruction

  • – Patent ductus arteriosus

  • – Transposition of the great arteries

  • – Truncus arteriosus

  • – Double-outlet right or left ventricle

  • – Anomalous entry of the coronary sinus into the left atrium

  • – Coarctation of the aorta

• The left ventricle functions as a univentricle and receives the entire systemic, coronary, and pulmonary venous return

• Congestive heart failure may develop in the setting of increased pulmonary blood flow

CLINICAL PRESENTATION

SYMPTOMS AND SIGNS

• The clinical presentation depends on the magnitude of pulmonary blood flow

• Neonates with reduced pulmonary blood flow present early with profound cyanosis

• Infants with increased pulmonary blood flow may present later with symptoms of congestive heart failure (dyspnea, fatigue, and difficulty feeding); cyanosis may or may not be present

• Other symptoms:

  • – Recurrent respiratory tract infections

  • – Failure to thrive

PHYSICAL EXAM FINDINGS

Reduced pulmonary blood flow:

• Tachypnea

• Central cyanosis

• Normal pulses

• Holosystolic murmur of a VSD at the lower sternal border

• Systolic ejection murmur (or no murmur) and single S₂ in patients with pulmonary atresia

Increased pulmonary blood flow:

• Minimal or absent cyanosis

• Elevated jugular venous pressure

• Hyperdynamic precordial impulse

• Single or split S₂

• S₃ may be present

• Holosystolic murmur of a VSD at the lower sternal border

• Mid-diastolic rumble at the apex due to increased flow across the mitral valve

• Pulmonary rales and/or peripheral edema may be present

DIFFERENTIAL DIAGNOSIS

• Ebstein’s anomaly with intermittent cyanosis

• Pulmonary atresia with intact ventricular septum

• Complete transposition of the great arteries

• Other causes of cyanosis and heart failure

DIAGNOSTIC EVALUATION

LABORATORY TESTS

• Arterial blood gases and pulse oximetry: demonstrate oxygen desaturation

• Microcytic anemia in patients who have had chronic phlebotomy without iron replacement

• Coagulation abnormalities

• Hyperuricemia

ELECTROCARDIOGRAPHY

• Right atrial enlargement

• Abnormal superior QRS vector (usually left-axis deviation in the frontal plane) or, less commonly, normal axis or right-axis deviation

• Left ventricular hypertrophy

• Decreased right ventricular forces

• Atrial arrhythmias occasionally seen in older ...