Cardiac emergencies and the Pediatrician Thomas R. Burklow, MD Asst C., Pediatric Cardiology Walter Reed Army Medical Center National Capital Consortium.

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