Question 1: Interpret the rhythm strip above (comment on regularity, rate, P wave, PR interval and QRS)?

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1 It is your first month on your NICU rotation and you are prerounding on your patients. The nurse takes you aside and says she s been seeing something funny on the cardiac monitor. You walk to the bedside of a full term, twin, who was discordant for weight and admitted for polycythemia and hypoglycemia yesterday. You look at the monitor and see this: Question 1: Interpret the rhythm strip above (comment on regularity, rate, P wave, PR interval and QRS)? Rate: newborn rate, HR > 100 Rhythm: regular except for premature beat P wave: should be p wave before every QRS, but morphology of p wave before PAC may be different. PR interval: minimum of 70 ms to a maximum of 140 ms, with a mean of 100 ms. QRS: narrow, less than 0.10 sec Interpretation: premature atrial contraction Question 2: Is this finding something you need to evaluate further? Order an ECG and as long as there is nothing concerning on it, then you do not need a further workup. If patient continues to have frequent PACs, then a follow-up ECG at 1 month may be performed. Relatively long periods of blocked atrial bigeminy may simulate sinus bradycardia. The distinction is important since blocked atrial bigeminy is most often benign while severe sinus bradycardia may accompany systemic illness. Question 3: Later in the day, you are reviewing the vitals for the same patient and notice that the blood pressure is 66/22 when previously it was 70/35. As you are walking

2 back to check on the patient, what is on your differential for widened pulse pressure in a neonate? DDx widened pulse pressure: Sepsis Fever Anemia Thyrotoxicosis Cardiac lesions o Coarctation of the Aorta (with a PDA) o PDA o Aortic regurgitation o AV fistula o Truncus arteriosus o Aortopulmonary window o Surgical shunts (ex: BT shunt) Bradycardia Question 4: You are at the bedside of the patient and you are trying to narrow down your differential. Fortunately, the patient is not showing any signs of sepsis, anemia or thyrotoxicosis. What would you look for on exam? How does the physical exam in Coarctation of the Aorta (CoA) change in an older patient? 1. Overall state lethargic vs active; may be restless and feed poorly. 2. Tachycardia 3. Pulses: palpate both brachial and femoral at same time to see if there is a delay after the brachial pulse before the femoral pulse (also known as brachial-femoral delay). This is a sign of CoA. However if there is a PDA present then you may not detect a delay. 4. Comparing the extremities: Is the upper extremity warmer than the lower extremity? Do you see differential cyanosis (bluish coloration of the lower but not the upper extremity and the head) or a difference in oxygen saturations? 5. Auscultation: with CoA and PDA you would not necessarily hear a murmur. A classic PDA murmur is a continuous machine-like murmur loudest at LUSB; however, in a newborn, you may only hear the systolic component. With a bidirectional PDA you won t hear a murmur. Lastly, you may hear a short diastolic murmur with aortic regurgitation, and a soft S1 because of elevated filling pressures closing the MV in diastole. 6. In teenager: You would typically diagnosis it via elevated blood pressure or brachial-femoral delay. It is rare nowadays to diagnosis CoA via rib notching on CXR since patients are diagnosed earlier.

3 Question 5: You think you notice a difference between the brachial and femoral pulses and you are concerned about the pulse pressure. What other tests can you order? 4-extremity BPs (to see if there is higher BP in upper extremities compared to lower), ECG (see #6), pre and post ductal sats (to see if lower extremities have lower sat 2/2 to right to left PDA flow), CXR (should be normal in neonate, unless they are developing heart failure), ECHO (see #7). Question 6: You order an ECG. What would you expect to find in this neonate? What if your patient were a teenager? NEONATE: normal and age-appropriate RV hypertrophy. RVH may be exacerbated by rapid constriction of a PDA, which then leads to acute increase in LV afterload, LV pressure that causes left to right shunting across the PFO and RV dilatation. TEENAGER: with late onset or diagnosis of CoA of the aorta the EKG may be normal or may reveal LV hypertrophy, and may show signs of LV ischemia or strain (increased voltage and ST and T wave changes in precordial leads). See figure on right. Question 7: You also consult cardiology to obtain an ECHO and see proximal narrowing of the proximal descending aorta near the ductus, confirming Coarctation of the Aorta (CoA). There was a PDA. You do not see any ventricular hypertrophy or dilatation of any chambers of the heart. Now that you know the baby has CoA, you wonder how that may have developed. What is the embryology of CoA? 1. Migration or extension of ductal tissue into the wall of the fetal thoracic aorta. 2. Reduced antegrade intrauterine blood flow causing underdevelopment of the isthmus. If flow through ductus is increased and through isthmus is decreased, the point at the junction of the two arteries will become exaggerated and form the shelf characteristic of CoA.

4 3. Migration of left seventh intersegmental artery that forms the left subclavian artery (Rudolph s) Question 8: What is the most common location for CoA and in what other locations can it occur? Most commonly the narrowing is of the descending aorta at the insertion of the ductus arteriosus, ie juxtaductal Narrowing can be anywhere from discrete thoracic lesions, long segmental defects, tubular hypoplasia and rarely coarctation of the abdominal aorta. Question 9: What other cardiac defects would you worry about in someone with CoA? In large study of 1892 patients from Boston Childrens, only 7% did not have any other cardiac anomaly besides bicuspid aortic valve o 1/3 had complex cardiac defects (single ventricle, AV canal, d-tga) o 1/5 had VSDs o Rest had other lesions: bicuspid aortic valve, ASD, PDA, MR, AS, AR Question 10: Now that you know your patient has CoA, what syndromes do you consider? Turner syndrome (most common) Kabuki syndrome (see below) PHACE syndrome (see below) Not syndrome but circle of Willis abnormality (Rudolph s) Kabuki syndrome is another condition in which aortic CoA is a common feature. 25% have CoA but other cardiac anomalies can occur. In addition, ASDs, VSDs, partial anomalous pulmonary venous return, or valvular pulmonic stenosis can be seen. Clinically, affected children exhibit long palpebral fissures with eversion of the lower third of the eyelid, arched eyebrows, prominent ears (often with ear pits), and persistence of the fetal fingertip pads. Renal ultrasonography can reveal kidney anomalies. At this time, the genetic cause of Kabuki syndrome is unknown. PHACE defined: Posterior fossa- These are brain malformations that are present at birth. Hemangioma- The hemangioma usually covers a large area on the skin of the head or neck (greater than 5 cm). The term "segmental" is sometimes used to describe these hemangiomas. Arterial lesions Abnormalities of the blood vessels in the neck or head.

5 Cardiac abnormalities/aortic CoA These are abnormalities of the heart or the blood vessels that are attached to the heart. Eye abnormalities. Question 11: The baby is maintaining his blood pressure with palpable femoral pulses, cap refill < 3 seconds even in the lower extremity and active. What are your next steps? 1. Consider PGE 2. Refer or speak with cardiothoracic surgeon to see when it should be repaired. **END** Sources: 1. Schwartz PJ, Garson A Jr, Paul T, Stramba-Badiale M, Vetter VL, Wren C; Guidelines for the interpretation of the neonatal electrocardiogram. A task force of the European Society of Cardiology. European Society of Cardiology. Eur Heart J Sep;23(17): Uptodate: Clinical manifestations and diagnosis of coarctation of the aorta. 3. Beck AE and Louanne Hudgins. Congenital Cardiac Malformations in the Neonate: Isolated or Syndromic? Neoreviews 2003; 4:e105-e110; doi: /neo.4-4-e Rudolph, Andrew. Congenital Diseases of the Heart: Clinical-Physiologic Considerations Third edition.