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Cardiac emergencies and the Pediatrician
Thomas R. Burklow, MDAsst C., Pediatric CardiologyWalter Reed Army Medical CenterNational Capital Consortium
Cardiac emergencies
Congestive heart failureHypercyanotic spellsTachyarrhythmiasHypertensive crisis
How do you know you are dealing with a cardiac emergency?
Case Presentation #1
4 month old presents to ER with cc: “cold symptoms”
5 day history of increasing cough; afebrile, no rhinorrhea, no ill contacts.
PMH: unremarkable. vigorous feeder (25-30oz/d) until the last couple of days.
FHx: father had a “leaky valve” but was cleared to join the Marines
Physical Examination
VS: HR 165, RR 60, normal BP throughout; RA O2 sat mid 80’s, increases to 97% on 1/4 L/ O2
Small for age male, nondysmorphic, mild cyanosis, moderate increased work of breathing
Left chest prominent Prominent PMI, RRR, S2 obscured by murmur,
gr III pansystolic SRM over apex to left axilla Liver edge 4 cm below RCM 1+ pulses throughout
Electrocardiogram
Chest X ray
What is the pathological condition which is present in this infant?
What information supports this supposition?
What do you do?
Clinical manifestations
Infant feeding
difficulties failure to thrive diaphoresis tachycardia tachypnea
Child breathlessness tachycardia tachypnea peripheral
edema cardiomegaly
What causes congestive heart failure?
Excessive work load: pressure or volume
Normal workload faced by a damaged myocardium
Etiologies
Neonate dysfunction volume pressure
Infant Volume Dysfunction
Child Palliated congenital
heart disease AV valve
regurgitation Acute rheumatic
fever Myocarditis Endocarditis
Neonatal congestive heart failure
Dysfunction Myocarditis Cardiomyopathy—think inborn error of metabolism Coronary artery anomaly Arrhythmias
Volume Unrestrictive ventricular septal defect(s) Truncus arteriosus
Pressure—think ductal-dependent left-sided obstruction
Hypoplastic left heart syndrome Critical aortic stenosis Critical coarctation of the aorta
CHF in infants and children
Dysfunction Myocarditis Cardiomyopathy—think inborn error of metabolism Coronary artery anomaly Palliated congenital heart disease Arrhythmias
Volume Unrestrictive ventricular septal defect(s) Severe atrioventricular valve dysfunction Truncus arteriosus Palliated congenital heart disease
How do you know what entity you are dealing with?...
Age An apparently well neonate who develops CHF
at 1-2 weeks...consider a ductal-dependent lesion
An apparently well child without known heart disease develops CHF…consider myocarditis
Fetal history of “irregular heart beats” Duration of symptoms Prior history of surgery Family history Travel history
Assessment--physical examination
Identify signs and symptoms of congestive heart failure
Blood pressures Pulse oximetry Presence of murmur MAY be helpful
Treatment
Digitalis oral: 8-10 mcg/kg/day I.V.: 80% of oral dose Because of varying metabolism, appropriate dose
varies by age Rapid digitalization
May be performed over 12-24 hours, 6-12 hours in dire situations
Calculate TDD (varies by age); administer 1/2 of TDD, followed by 1/4, then 1/4 of TDD
Case example: patient weight is 5.5 kg
Case example
5.5 kg in a 4 month old Oral TDD for 1 month-2 years is 30-50 mcg/kg
TDD is 220 mcg Administer 110 mcg now, then 55 mcg in 12
hours, then 55 mcg in 6 hours IV dose is 80% of the above amounts
Maintenance digoxin is approximately 1/4 of TDD, divided b.i.d., or at 50 mcg/cc, 0.1 cc/kg per dose b.i.d.
Digoxin toxicity
Levels are helpful only in cases of suspected toxicity, not for management
GI symptoms are common presenting symptoms: nausea, vomiting, anorexia
Most common sign of cardiac toxicity is arrhythmia: bradycardia, AV block, PVCs
Treatment includes holding doses for 1-2 half lives, atropine for sinus bradycardia, and “FAB” fragments in cases of significant toxicity
Other medications
Diuretics Furosemide (Lasix); 0.5-1.0 mg/kg/dose Chlorothiazide (Diuril); 20-50 mg/kg/day Spironolactone (Aldactone); 1-2 mg/kg/day
Afterload reduction Captopril (Capoten); 0.1-0.5 mg/kg/dose t.i.d. Enalapril (Vasotec); 0.1 mg/kg/day
Beta-blocker Labetolol Carvediolol
A couple words regarding critical left sided obstructive lesion…
Critical obstruction to cardiac output
Hypoplastic left heart syndrome Critical aortic stenosis Critical coarctation of the aorta
The common endpoint for these three lesions is loss of systemic cardiac output when the ductus closes….
Physiology of hypoplastic left heart
STOP
Prostaglandin
PGE1
Powerful ductal dilator Mechanism of ductal closure
High oxygen tension Circulating prostaglandins Genetic predetermination
Prostaglandin dosing
Starting dose: 0.1 mcg/kg/min
Or… One ampule is 500 mcg/1 cc Mix one amp in 82 cc of normal saline Run resulting mixture at 1 cc/kg/hr, this will
be equivalent to 0.1 mcg/kg/min
Case presentation #2
Two month old African-american infant presents to the 2 month well baby visit
Mother has no concerns: feeding well, no tachypnea.
Family history is unremarkable
Physical Examination
VS: HR 180; RR 25, BP 85/45, room air oxygen saturations 84%
Ht 25th percentile, Wt 25th percentile General features: non-dysmorphic
infant female Abdomen: Liver edge palpable at
RCM Ext: 2+ radial and femoral pulses
Cardiovascular examination
Prominent right ventricular impulse, subxiphoid
Normal S1 with a single S2 Harsh systolic murmur noted at the left
mid-upper sternal border, with radiation to back and axilla
Diastole: quiet Extra cardiac sounds: none
Electrocardiogram
Chest radiograph
While discussing the most likely diagnosis with the parents, you are called away. However, you are urgently called back to the examination room by the clinic nurse. The parents state that while the infant was crying, her complexion became intensely dark (“she’s never done this before”) and becamely listless…
The pulse oximeter is reading a HR of 170 and an pulse oximetry reading of less than 70%. Upon auscultation, you note the murmur is diminished in intensity.
?
Hypercyanotic spell
a.k.a. “Tet spell”, “paroxysmal hyperpnea” Etiology uncertain
“Infundibular spasm” Decrease in systemic vascular resistance
Goal of therapy is to increase pulmonary blood flow
PVRPVR
SVRSVR
Recognition of hypercyanotic spell
Symptoms include: irritability, crying, loss of consciousness
Physical examination may demonstrate tachypnea, deepening of cyanosis, and loss of systolic ejection murmur
Laboratory data would reveal metabolic acidosis
Treatment
Soothing Knee-chest positioning Morphine, 0.1-0.2 mg/kg IV or SC Oxygen (perhaps limited value) Intravenous volume expansion, 10 cc/kg isotonic Sodium bicarbonate 1-2 mEq/kg/dose Propanolol, 0.15-0.25 mg/kg IV over 2-5 minutes Phenylephrine, 0.1 mg/kg IM or SC General anesthesia
The End…for now