A 9-month-old infant with known tetralogy of Fallot has an acute episode of increased cyanosis, restlessness, and hyperpnea after waking from a nap. During the spell, the systolic ejection murmur becomes softer. What is the most appropriate initial management step?
A 3-day-old neonate presents with profound cyanosis, with an oxygen saturation of 70%. A chest x-ray is obtained, which reveals a normal heart size and decreased pulmonary vascular markings. Based on this combination of clinical and radiographic findings, which of the following is the most likely diagnosis?
A 7-year-old child with a history of chronic kidney disease presents to the emergency department with a blood pressure of 160/110 mm Hg, severe headache, and vomiting. A diagnosis of hypertensive emergency is made, and he is admitted to the pediatric intensive care unit for intravenous antihypertensive therapy. What is the recommended therapeutic goal for blood pressure reduction over the first 8 hours?
A 4-month-old infant presents with incessant tachycardia and a dilated cardiomyopathy. ECG shows a narrow complex tachycardia at 190 bpm with atrioventricular dissociation. The diagnosis of congenital junctional ectopic tachycardia (JET) is made. Chronic therapy is initiated. Which of the following is a known, important complication of catheter ablation for this condition?
An 8-year-old girl with Marfan syndrome is being followed by cardiology. On examination, she has a late systolic murmur at the apex. Echocardiography shows single leaflet prolapse > 2 mm beyond the long-axis annular plane, with valve leaflet thickening of 6 mm. How would her condition be classified?
A 14-year-old girl with Noonan syndrome is followed by cardiology for known valvular pulmonary stenosis. She is asymptomatic. On physical exam, a prominent presystolic ‘a’ wave is noted in her jugular venous pulse. Her electrocardiogram confirms right ventricular hypertrophy. The prominent ‘a’ wave is a sign of what physiologic consequence of her condition?
A newborn with tuberous sclerosis is found on a screening echocardiogram to have a large cardiac rhabdomyoma causing significant left ventricular outflow tract obstruction and symptomatic heart failure. While observation is typical for asymptomatic tumors, what medication may be administered to this symptomatic patient to enhance tumor resolution?
A 6-year-old boy with a history of a completely repaired tetralogy of Fallot with a prosthetic pulmonary valve 3 years ago is scheduled for a dental extraction. He has no residual defects. According to the 2007 AHA guidelines cited, what is the appropriate recommendation regarding antimicrobial prophylaxis?
A healthy 13-year-old competitive swimmer is noted to have a resting heart rate of 55 beats/min during a sports physical. He is asymptomatic and has excellent exercise tolerance. His ECG confirms sinus bradycardia. What is the most likely clinical significance of this finding?
A neonatologist administers verapamil to a 2-day-old infant for a supraventricular tachycardia. The infant subsequently develops profound myocardial depression and hypotension. What developmental characteristic of the neonatal myocardium best explains this heightened sensitivity to calcium channel blockers?