Chapter 5. Cardiology

Clinical Summary

Bradycardia is a heart rate below normal range for age with many etiologies. Bradycardia of <60 beats per minute (bpm) associated with poor systemic perfusion is clinically significant. Signs include poor skin perfusion with pallor, cyanosis, cool mottled extremities, prolonged capillary refill, thready, weak, or absent peripheral pulses, and discrepancy in volume between peripheral and central pulses. Patients are irritable, lethargic, confused, or have decreased level of consciousness. Severe bradycardia may cause respiratory difficulty, decreased pulse pressure of >20 mm Hg, hypotension (decompensated shock), and decreased or no urine output. There are several types of bradyarrhythmias including sinus bradycardia, sinus node arrest with a slow junctional or ventricular escape rhythm, and atrioventricular (AV) block.

ECG is necessary to exclude second-degree or complete heart block (CHB), and findings include a slow heart rate with P waves that may or may not be visible. QRS duration is normal or prolonged (depending on the location of the intrinsic cardiac pacemaker). Dissociation of P waves and QRS is seen in CHB. P wave with a normal PR interval preceding each QRS complex is seen in sinus bradycardia.

Emergency Department Treatment and Disposition

Stabilize ABCs and observe and reassess patients with bradycardia not associated with evidence of poor systemic perfusion and admit for continued observation. Consult cardiology for asymptomatic bradycardia from drug ingestion, complete AV block, acquired or congenital heart disease (CHD), or patients with refractory bradycardia that require pacing.

If cardiorespiratory compromise is present, emergent intervention to establish a patent airway and assist breathing with delivery of 100% oxygen. Perform chest compressions if the patient fails to improve (patient remains unresponsive or flaccid with poor systemic perfusion), the heart rate remains <80 bpm in neonates or <60 bpm in infants and children. If there is no response to effective oxygenation and ventilation, give epinephrine. A continuous epinephrine, isuprel, or dopamine infusion titrated to effect may be required. For symptomatic bradycardia due to vagal stimulation, cholinergic drug toxicity, or primary AV block, give atropine as the drug of choice. Atropine usually is not effective for hypoxic-ischemic induced bradycardia. Vagally induced bradycardia usually resolves once the stimulation is withdrawn. Atropine is very effective if used prophylactically before vagal stimulation in procedures such as endotracheal intubation.

Pacing is not helpful in children with bradycardia secondary to postarrest hypoxic-ischemic myocardial insult. It may be helpful for bradycardia caused by acquired or CHD causing CHB or sinus node dysfunction. Options include transcutaneous, transvenous, or transesophageal pacing.

Pearls

1. Asymptomatic sinus bradycardia can occur as a normal variant during deep sleep and is also common in highly trained athletes.

2. Most common causes of symptomatic bradycardia are hypoxemia and vagal stimulation, and if not corrected may degenerate into full cardiac arrest.

Clinical Summary

First-degree AV block is prolongation of the PR interval beyond the norm for age. PR interval is determined by the point of conduction from the sinus node to the onset of QRS. The PR interval and QRS duration are age-dependent measures of AV conduction. Impaired conduction is classified as first-degree, second-degree, or third-degree heart block. The normal PR interval changes with both age and heart rate, but it is more age dependent. The AV node is usually the site of conduction delay, although it may occur in the atrium or the infranodal level. ECG findings of first-degree AV block includes a regular rhythm that originates in the sinus node with a prolonged PR interval and a normal QRS morphology, and etiologies are mentioned in Table 5.3.

Emergency Department Treatment and Disposition

Consult cardiology and hospitalize patients with first-degree heart block associated with underlying serious heart disease (eg, acute rheumatic fever, myocarditis) for evaluation and appropriate therapy.

Pearl

1. First-degree AV block alone does not lead to hemodynamic compromise and does not need any specific therapy.

Clinical Summary

Second-degree AV block is when one or more (but not all) of the atrial impulses fail to conduct to the ventricles because of impaired conduction. Two distinct types of second-degree AV blocks are type I, second-degree AV block (also known as Mobitz I or Wenckebach periodicity) and type II second-degree AV block (also known as Mobitz II). Mobitz type I heart block can occur as a normal variant (without any symptoms) in children. Causes of second-degree AV block include myocarditis, atrial septal defect, acute rheumatic fever, Ebstein anomaly, cardiomyopathy, structural congenital heart disease, drug toxicity (eg, digitalis, beta-blockers), increased vagal tone (any etiology), and following surgery near the AV junction. Patients with Mobitz type II may present with syncope or heart failure. Diagnosis is confirmed by ECG. A chest radiograph may show cardiomegaly, depending on the underlying etiology (eg, myocarditis, cardiomyopathy).

Emergency Department Treatment and Disposition

Evaluate patient and consult cardiology to determine the underlying etiology for the second-degree heart block. Admit newly diagnosed patients, those with postcardiac surgery heart block, and symptomatic patients (eg, syncope or dizzy spells) as they may need pacemaker implantation. Treat the underlying cause in patients with Mobitz type I AV block. The prognosis of Mobitz type II AV block associated with a wide QRS complex may progress to complete heart block (CHB). If signs of hypoperfusion are present with slow ventricular rates, give atropine emergently. Alternatively, Isoproterenol can be used with caution (eg, in patients with digoxin toxicity). Transcutaneous cardiac pacing may be required for patients who do not respond to atropine. A permanent transvenous cardiac pacemaker is required if symptoms of presyncope or syncope occur.

Pearls

1. Mobitz type I heart block is often transient (eg, seen with myocarditis).

2. Mobitz type II heart block is usually permanent, and implies structural damage to the infranodal conducting system.

Clinical Summary

Third-degree AV block, or CHB, occurs when no impulses from the atria reach the ventricles. Because the impulse is blocked, an accessory pacemaker will typically activate the ventricles (an escape rhythm). Third-degree heart block is rare in the pediatric age group. Signs and symptoms in patients with an otherwise normal heart vary. Patients may be bradycardic and asymptomatic. Older children may present with syncope (syncope from a high-degree AV block not related to positional changes or exertion is called a Stokes-Adams attack). Older infants may present with night terrors, irritability, or tiredness with frequent naps. Acquired heart block is frequently symptomatic, or present with syncope, congestive heart failure (CHF), shock, or sudden death. Peripheral pulses may be prominent secondary to large compensatory stroke volume. Chest radiograph may show cardiomegaly secondary to increased diastolic ventricular filling.

Emergency Department Treatment and Disposition

Admit symptomatic patients (eg, syncope, CHF) or those newly diagnosed with CHB. Symptomatic newborns (eg, heart failure, evidence of hydrops) with CHB with ventricular rates ≤50 bpm require cardiac pacing. Adrenergic agents (epinephrine or isoproterenol) or a vagolytic agent (atropine) may be tried to increase the heart rate while awaiting placement of the pacemaker. Cardiac pacing (transthoracic, transcutaneous, or transvenous) is also required in symptomatic patients with CHB and CHD. Temporary pacing may be required in postoperative CHB following surgery for CHD.

Pearls

1. Autoimmune disease accounts for 60% to 70% of all cases of congenital CHB.

2. About 25% to 33% of cases of CHB occur in patients with associated structural heart disease.

3. Complete heart block may not present at birth in infants born to mothers with systemic lupus erythematosus (SLE), and may develop within the first 3 to 6 months after birth. Unlike other manifestations of neonatal lupus that resolve, CHB is permanent and patients often require cardiac pacing.

4. An implantable pacemaker is used to prevent sudden death in symptomatic patents with CHB.

Clinical Summary

Long QT syndrome (LQTS) is a pathologically prolonged corrected QT interval that may be acquired, but more often is congenital and inherited. Prolongation of the QTc interval results from a prolongation of the refractory period of the myocardium (during which the atrium is still firing at its regular pace), leading to torsades de pointes (“R-on-T phenomenon,” a malignant form of ventricular tachycardia [VT]). Patients present with syncope or presyncope episodes (recurrent, often precipitated by exercise, fright, or being startled), seizures or episodes of paroxysmal VT (often with torsades de pointes morphology that can progress to ventricular fibrillation and sudden death). LQTS may be an incidental ECG finding. There may be a family history of sudden death in young relatives, syncope with exercise or emotional stress, seizures, arrhythmias, and hearing impairment (congenital LQTS). The QT interval may be so prolonged in neonates that it may lead to second-degree or complete heart block.

Emergency Department Treatment and Disposition

Treatment of VT associated with LQTS includes support of airway, breathing, and circulation (ABCs) and providing oxygen and ventilation as needed. Intravenous lidocaine, or amiodarone, or procainamide can be used. If the above medical therapy fails, synchronized cardioversion is used for stable patients with VT with palpable pulses and defibrillation for patients with pulseless VT as per PALS protocols.

Consult cardiology for any patient with LQTS. ECG features of LQTS include low heart rate for age, notched T waves, and T-wave alternans. Stress testing (exertional LQTS), or 24-hour Holter monitoring (intermittent LQTS) may help in arriving at the final diagnosis. Long-term goals of therapy of LQTS include beta-blockade (propranolol is drug of choice) to prevent VT from progressing to ventricular fibrillation and sudden death and to blunt heart rate response to exercise. Therapy should be continued for life. A pacemaker may be required in some patients to overcome profound bradycardia (a common association). Exercise restriction, and avoiding drugs that are known to cause prolongation of the QT interval (see Syncope) are recommended. Advise parents to learn cardiopulmonary resuscitation (as exercise restriction and drug therapy may be ineffective for some children). An implantable cardioverter-defibrillator may be considered in patients with continued episodes of syncope in spite of therapy, and in those with a history of cardiac arrest.

Pearls

1. Patients with LQTS may have a normal ECG in the emergency department (ED).

2. Congenital LQTS results in a mortality rate in excess of 90% if not diagnosed and properly treated.

3. LQTS in association with hypertrophic cardiomyopathy accounts for up to half of the cases of sudden cardiac death.

4. Children with LQTS are predisposed to episodic ventricular arrhythmias, torsades de pointes, syncope, and generalized seizures.

5. Patients with LQTS may develop fatal ventricular arrhythmias, especially if exposed to some medications such as antihistamines, macrolide antibiotics, or phenothiazines.

6. All family members of a patient with LQTS should undergo a 12-lead ECG (and cardiac evaluation as indicated).

7. Any patient presenting with VT (especially torsades de pointes or a polymorphic type) should have a corrected QT interval determined while in sinus rhythm.

Clinical Summary

Syncope is a sudden and brief loss of consciousness accompanied by a loss of postural tone with spontaneous recovery. It result from a sudden decrease or brief cessation of cerebral blood flow.

Vasovagal syncope (neurocardiogenic syncope, fainting spell) is the most common and includes emotional fainting, situational syncope, syncope with panic, and syncope associated with exercise in athletes (without heart disease). Vasovagal syncope is usually seen in adolescents and most often occurs after prolonged standing (eg, crowded, warm environment), or with noxious stimuli, strong emotions, or fatigue.

Orthostatic syncope occurs while standing or during a rapid change from supine or sitting position to standing. Measure orthostatic blood pressure (BP) 3 minutes after patient stands up following a supine period of 5 minutes (orthostatic changes present if BP changes >15 mm Hg and HR changes >10 bpm). Predisposing events include dehydration, acute blood loss, or vasodilator drugs.

Cardiac syncope results from hypoxemia due to cyanotic heart disease or decreased cardiac output secondary to arrhythmia, obstructive lesion, or myocardial dysfunction. Syncope occurs during physical exertion (eg, LQTS). Syncope occurs suddenly without warning.

Breath-holding spells are commonly seen between 1 and 5 years of age (peaks around 2 years of age) and resolves spontaneously by school age. There are two major types: cyanotic type (about 80%) and pallid type (about 20%). Provoking events include pain, anger, frustration, vigorous crying followed by forced expiration and apnea (breath-holding spell). Unconsciousness occurs due to decreased cardiac output. Generalized clonic jerks, opisthotonus, and bradycardia and incontinence may occur. Normal physical examination (including cardiac and neurologic) is a hallmark.

Emergency Department Treatment and Disposition

Determine the degree of hemodynamic stability including orthostatic BP and HR measurements. Specific treatment of syncope depends on the underlying etiology (eg, LQTS). Routine basic laboratory tests (eg, CBC, electrolytes, glucose) are rarely helpful. Obtain additional tests as guided by the history and examination (eg, toxicology screen, carboxyhemoglobin). Exclude pregnancy in adolescent girls. Obtain a 12-lead ECG (with rhythm strip) in all patients (in spite of its low yield) because findings can lead to specific therapy (eg, pacemaker for complete heart block, beta-blocker for LQTS). Arrhythmias that lead to syncope may not be present. Consider 24-hour Holter monitoring. Consult cardiology if cardiac syncope is likely based on history/examination or abnormal ECG findings or syncope with chest pain, arrhythmias, or palpitations, or a family history of sudden death. Consult neurology if seizures cannot be excluded based on the history or with an abnormal neurologic examination.

Reassure and educate patients about the benign nature of vasovagal syncope, identifying and avoiding precipitating factors (eg, dehydration, ensure intake of salty foods during intense physical activity). Advise patients to learn to recognize prodromal symptoms and assume a sitting or supine position with elevation of the feet. For orthostatic syncope, provide fluid therapy to patients with volume depletion. Encourage patients to get up slowly after lying or sitting and discontinue or reduce the dose of any medication that may be responsible.

Admit patients presenting with recurrent syncope of undetermined etiology, cardiac syncope (eg, LQTS tachyarrhythmia, or symptoms suggestive of arrhythmias [eg, syncope associated with palpitations, exertional syncope], atrioventricular block, valvular or congenital heart disease, pacemaker malfunction, congestive heart failure, cyanotic spells).

Pearls

1. Syncope is a symptom, not a disease.

2. A thorough history and physical examination are essential for the evaluation of syncope and may lead to or suggest a diagnosis that can be evaluated with directed testing.

3. Vasovagal syncope is the most common cause of fainting in children and adolescents and accounts for >50% of cases of childhood syncope.

4. Dizziness, vertigo, and presyncope do not result in loss of consciousness or postural tone.

Clinical Summary

Sinus tachycardia (ST) is a rate of sinus node discharge higher than normal for the patient’s age (see Table 5.1). The usual upper limit in infants and young children (up to 5 years old) is up to 200 bpm. The upper limit in older children is up to 180 bpm. Tachycardia is a physiological response to the body’s need for increased cardiac output (CO) or oxygen delivery (tachycardia is the first sign of hypovolemia: CO = SV × HR; thus to maintain cardiac output, a compensatory increase in HR occurs, as the child’s ability to increase stroke volume [SV] is limited). ST is a nonspecific sign of an underlying condition rather than a true arrhythmia. On an ECG, all P waves are normal in configuration (upright in lead II), all QRS complexes are preceded by a P wave. The P-, QRS-, and T-wave morphology are normal.

Emergency Department Treatment and Disposition

Use continuous cardiac and pulse oximetry monitoring for patients presenting with ST near the range of supraventricular tachycardia (SVT) (eg, HR approaching 200 bpm), and treat the underlying cause of ST: antipyretics for fever, oxygen therapy for hypoxia, fluid therapy for hypovolemia, pain management. Do not attempt to decrease heart rate with pharmacologic or electrical intervention. ST usually resolves once the stressor ceases and the heart rate returns to normal levels with appropriate treatment of the underlying cause.

Pearls

1. ST is the most common rhythm disturbance in children.

2. Treatment of ST involves treatment of the underlying cause.

3. Persistent ST without an apparent inciting cause may be indicative of occult cardiac disease (eg, myocarditis) or an unrecognized noncardiac condition (eg, hypovolemia).

Clinical Summary

Supraventricular tachycardia (SVT) is a heart rate in infants and young children >220 bpm (range: 220–320 bpm) and heart rate in older children >180 bpm (range: 180–250 bpm), most commonly caused by a reentry mechanism involving atrioventricular [AV] nodal reentry, accessory pathways, or increased automaticity. SVT due to accessory pathway conduction (eg, Wolff-Parkinson-White syndrome [WPW syndrome]) is the predominant mechanism in the fetus and young infant. AV nodal reentry typically appears in 5- to 10-year-old children, and is the predominant mechanism in adults. Primary atrial tachycardia (eg, atrial flutter or fibrillation) accounts for 10% to 15% of SVT at all ages. Associated structural heart disease (eg, Ebstein anomaly, corrected transposition of the aorta) is present in about 20% of cases. Other etiologies include drugs (eg, cold medications containing sympathomimetics), hyperthyroidism, myocarditis, cardiomyopathy, or infections.

Infants usually present with nonspecific symptoms of poor feeding, irritability, or restlessness. If SVT persists for many hours at rapid rates, signs of congestive heart failure (eg, tachypnea, tachycardia, hepatomegaly) or cardiogenic shock/cardiovascular collapse (eg, an acutely ill infant with prolonged capillary refill, thready pulses, poor tissue perfusion, ashen color, and metabolic acidosis) develop. Infants may be completely asymptomatic and SVT may be detected during a routine examination. Older children may present with pounding or racing heartbeat, dizziness, diaphoresis, or tiredness. Episodes of SVT are often paroxysmal. Older children may give a history of episodes of a racing heartbeat that starts and stops suddenly. Chest pain is not a usual presenting symptom of SVT. Clinically the heart rate may be too rapid to count.

Most first episodes of childhood SVT occur in the first 2 months of life. About 60% of cases happen in infants <4 months of age and 80% of cases in infants <12 months of age. ECG is required to confirm the diagnosis. P waves may not be visible (obscured by the ST segment), which helps distinguish it from sinus tachycardia; narrow QRS complex is seen in 90% of cases and wide QRS complex is seen in 10% of cases (aberrant SVT). With persistent tachycardia, ST- and T-wave changes consistent with myocardial ischemia may be seen. Features of WPW syndrome may be seen once the episode of SVT terminates, and may include a short PR interval, a delta wave (slow upstroke of QRS complex), and a wide QRS complex. WPW syndrome sometimes closely resembles bundle branch block and must be distinguished.

A chest radiograph may show the presence of cardiomegaly, suggesting CHF or underlying structural heart disease.

Emergency Department Treatment and Disposition

Evaluate the hemodynamic status and stabilize as indicated providing high-flow oxygen, continuous cardiac, blood pressure, and pulse oximetry monitoring. Consult cardiology for echocardiography in patients with a first episode of SVT to exclude structural heart disease and to start long-term maintenance therapy (eg, digoxin, propranolol, procainamide, or amiodarone) as indicated with either a first episode or recurrent episodes of SVT. Possible electrophysiology testing and radiofrequency catheter ablation is needed for patients with refractory SVT, those requiring multiple medications, or those with undesirable side effects from medications.

ED treatment for SVT without circulatory compromise (stable patient) involves vagal maneuvers that heighten the vagal tone to the AV node. Application of an ice bag to the face in infants or submersion of the face in ice cold water in older children can be tried first (Caution: Application of ice to infants should be brief [10 to 20 seconds max], and a cloth or plastic barrier should be used to avoid the occurrence of fat necrosis. Avoid repeated applications of ice to the same location.). Other maneuvers include Valsalva maneuver (asking patient to strain as if straining at stool), unilateral carotid massage (massage at the junction of the carotid artery and the mandible). Ocular pressure should not be used (because of the risk of retinal detachment).

Medical therapy includes adenosine and verapamil. Do not use verapamil in infants <1 year of age (life-threatening side effects include profound bradycardia, hypotension, cardiac arrest), in children with CHF, myocardial depression, or those receiving beta-blockers. For SVT with circulatory compromise or severe CHF (unstable patient with shock, acidosis), adenosine can be tried first if immediate vascular access is available. If not, perform synchronized cardioversion to terminate SVT quickly. Consider sedation in older children (if the patient is conscious and time and clinical condition allow; however, sedation must not delay cardioversion). Reconsider the diagnosis of SVT if conversion to sinus rhythm does not occur; patient may actually have sinus tachycardia. Admit any patient presenting with hemodynamic instability to the intensive care unit (ICU). Admit patients with a first episode of SVT (eg, for parental and patient education, beginning maintenance therapy, especially in neonates and infants with possible recurrences of SVT) for further management.

Discharge patients with previously diagnosed SVT once converted to sinus rhythm with a follow-up appointment with the cardiologist or primary care physician.

Pearls

1. SVT is the most common dysrhythmia seen in the pediatric age group.

2. Aberrant SVT presents with a wide QRS complex and may resemble VT. If uncertain, all wide-complex tachycardias are assumed to be VT.

3. A diagnosis of sepsis may be mistakenly made in an infant with SVT presenting with poor feeding, irritability, rapid breathing, or shock.

4. Do not delay cardioversion in severely compromised patients while trying to establish vascular access.

5. Do not prescribe sympathomimetics (common in over-the-counter decongestants) for the treatment of upper respiratory infections in children with SVT, and advise patients also to avoid caffeine.

Clinical Summary

Atrial flutter (AF) is an atrial rate >300 bpm (range: 240–450 bpm) with a ventricular response with varying degrees of block (eg, 2:1, 3:1, 4:1), and normal QRS complexes. It is most commonly caused by an ectopic pacemaker in the atrium leading to “circus movement” (reentry mechanism) within the atrium. It is most commonly seen in newborns with a structurally normal heart; however, it can happen at any age following heart surgery involving the atria (eg, repair of atrial septal defect). Atrial flutter in the newborns behaves differently than in older children. Atrial flutter is characterized by a F wave with saw tooth configuration on ECG. The ventricular rate determines eventual cardiac output; a too rapid ventricular rate may decrease cardiac output.

Emergency Department Treatment and Disposition

Evaluate hemodynamic status and stabilize the patient as indicated including high-flow oxygen, continuous cardiac, blood pressure, and pulse oximetry monitoring. Consult cardiology for echocardiography in patients with a first episode of AF to exclude associated structural heart disease or a thrombus in the atrium. Atrial flutter without circulatory compromise requires digitalization provided it is not from digitalis toxicity. Digitalis increases the AV block and thereby slows the ventricular rate. Propranolol may be added to digoxin. Amiodarone is also effective in acute treatment. Atrial flutter with circulatory compromise or severe CHF may require electric cardioversion. Patients who are on digoxin cannot undergo cardioversion. Rapid atrial pacing with a catheter in the esophagus or in the right atrium can be effective when cardioversion is contraindicated. Long-term maintenance therapy (eg, digoxin, propranolol, or amiodarone) is usually indicated in patients with either a first episode or recurrent episodes of AF.

Pearls

1. Atrial flutter is the second most common arrhythmia in neonates after supraventricular tachycardia.

2. Recurrence of AF is less likely in neonates and infants after successful conversion.

3. Suspect a significant cardiac pathology (eg, myocarditis) with AF in an older child with a structurally normal heart.

4. Exclude thrombus in the atrium before cardioversion to prevent embolization.

Clinical Summary

Premature ventricular contractions (PVCs), also known as ventricular premature contraction and ventricular extrasystoles, are premature, wide, and bizarre-shaped QRS complexes originating from ventricular tissue. PVCs are commonly seen in asymptomatic healthy adolescents but can be seen in any age group including newborns. Patients present with palpitations or “skipped beats,” chest discomfort, chest pain, syncope, dizziness, and difficulty breathing. Sometimes irregular heartbeat is detected during routine examination or as an incidental finding in ECG. Frequent PVCs in the presence of compromised cardiac function may produce signs of CHF. ECG findings include widened, bizarre QRS complexes that are not preceded by P waves. P wave may show AV dissociation or retrograde conduction or may be absent. The T-wave polarity usually is opposite to the major QRS deflection. A compensatory pause often follows a PVC. A rhythmic pattern of PVC with a fixed ratio with normal beats is referred to as bigeminy (1:1), trigeminy (2:1), or quadrigeminy (3:1). PVCs could be unifocal or multifocal. If three or more PVCs occur together and lasts for 10 seconds or less then it is described as nonsustained ventricular tachycardia (VT). A 24-hour Holter monitor, exercise stress testing, and echocardiography may be considered per consultation with the cardiologist.

Emergency Department Treatment and Disposition

Patients with “benign” PVCs do not require any treatment. Educate the patient/family about the benign nature and about avoiding stimulants (eg, excess caffeine intake, sympathomimetic agents). Cardiology consultation and hospitalization is necessary for “serious” PVCs, for patients presenting with cardiac symptoms (eg, syncope, chest pain) with PVCs, and patients with new onset of PVCs with underlying heart disease. Treatment may include lidocaine, procainamide, propranolol, or amiodarone.

Pearl

1. If a PVC falls on the T wave of the preceding normal complex (R-on-T phenomenon), it may initiate VT.

Clinical Summary

Tetralogy of Fallot (TOF) is most common cyanotic heart disease and consists of a spectrum of anatomic abnormalities (“tetrad”) that includes a large unrestrictive malaligned ventricular septal defect (VSD), right ventricular (RV) outflow tract obstruction (infundibular pulmonary stenosis [PS]), RV hypertrophy, and overriding of the aorta. The severity of PS ranges from mild to severe PS or to pulmonary atresia. Clinical presentation of TOF depends on the nature and degree of infundibular PS. An ejection systolic murmur is usually heard at the mid-upper left sternal border (murmur of PS) and may radiate toward the back. The loudness of the murmur depends on the volume of blood flowing across the outflow tract. Varying degrees of cyanosis due to right-to-left shunt resulting in an oxygen saturation of 75% to 85% is seen. Cyanosis shows minimal improvement with O2 supplementation. Other findings include increased RV impulse at the lower left sternal border (due to RV hypertrophy), loud single heart sound (pulmonary closure sound very soft) and digital clubbing. Cyanotic spells in infants and children with TOF are referred as hypercyanotic spells (also known as Tetralogy spells or “Tet spells”. Increased RV outflow tract obstruction exaggerates a right-to-left shunt, resulting in a decrease in pulmonary blood flow and a hypercyanotic spell (nearly all of the blood in the RV crosses through the VSD and enters the aorta). Complete blood count shows polycythemia (compensatory due to chronic hypoxemia). The ECG shows RV hypertrophy with right axis deviation. Radiography in infants may be normal or may show only decreased pulmonary vascular markings. In older children a “Boot-shaped heart” is seen.

Emergency Department Treatment and Disposition

Admit patients with hypercyanotic spells requiring more than O2 therapy and positional interventions to abate the spell and patients with complications related to prolonged hypoxemia (eg, seizures). Consult cardiology for further management of the hypercyanotic spell. Maintenance medical therapy may be required to control recurrent hypercyanotic spells (eg, propranolol) awaiting surgical intervention.

Pearls

1. Two hallmarks of TOF are a PS murmur and cyanosis.

2. Hypercyanotic spells of TOF are very dramatic in their presentation. Failure to recognize without immediate intervention may result in hypoxic seizures, profound metabolic acidosis, cerebrovascular accident (due to polycythemia/hyperviscosity), deterioration in cardiac rhythm, and death.

3. Increasing cyanosis in a child with a history of heart disease or history of squatting with exertion is an important clue indicating a potential hypercyanotic spell.

4. A notable absence or lessening of a previously heard heart murmur in a cyanotic child is the most important clue suggesting a hypercyanotic spell.

Clinical Summary

Hypoplastic left heart syndrome (HLHS) refers to a spectrum of CHDs that have very small LV and other associated anatomic abnormalities. There is inadequate anterograde flow to support the systemic circulation because of the hypoplasia of the left heart. Because systemic circulation is supported by the right side of the heart through the ductus arteriosus, these lesions are referred to as ductal-dependent lesions. Examples of ductal-dependent systemic blood flow lesions include HLHS, critical coarctation of the aorta and aortic arch interruption. Examples of right-sided ductal-dependent lesions (pulmonary circulation dependent on patency of the ductus arteriosus) include pulmonary atresia with intact ventricular septum, tricuspid atresia and critical pulmonary stenosis; HLHS, a representative of ductal-dependent lesions, is one of the most serious cardiac anomalies presenting in infancy. A neonate born with HLHS appears normal with normal Apgar scores because systemic perfusion and oxygenation are normal in utero. Typically, on day 2 or 3 of life, signs of poor systemic perfusion occur as the ductus arteriosus closes. All patients with HLHS have a single, loud second heart sound and variable heart murmurs that are usually not diagnostic. The ECG may show right atrial enlargement (˜30%–40%), right ventricular hypertrophy (˜80%–90%) and diminished left ventricular forces (˜30%–40%). Radiograph typically shows marked cardiomegaly with normal to increased pulmonary markings.

Emergency Department Treatment and Disposition

All ductal-dependent cardiac lesions present in a similar fashion (like HLHS), and the initial medical management is identical in all. Support the ABCs and provide continuous cardiac and pulse oximetry. Maintain ductal patency with an infusion of prostaglandin E1 (PGE1). Treat metabolic acidosis by fluid therapy and sodium bicarbonate (acidosis leads to increased systemic vascular resistance, and in turn increases pulmonary blood flow). Avoid any maneuvers that decrease pulmonary vascular resistance and pulmonary pressure as these will steal blood flow from the systemic circulation (eg, supplemental O2 therapy [O2 acts as pulmonary vasodilator] and hyperventilation [low PCO2 acts as pulmonary vasodilator]). Aim at the “ideal arterial blood gas with 7.4/40/40” (pH 7.4, PO2 40 mm Hg, PCO2 40 mm Hg). This is usually achieved with low (or no) mechanical ventilatory support on room air. After initial stabilization, all patients require admission to the pediatric ICU for subsequent management. Consult cardiology (after stabilization) to confirm the diagnosis by two-dimensional echocardiography and subsequent referral for surgical management.

Pearls

1. A ductal-dependent cardiac lesion must be considered in any neonate (up to 28 days old) with sudden onset of shock, severe hypoxemia, acidosis, or intense cyanosis (systemic circulatory collapse).

2. Neonates presenting with shock should be treated as having ductal-dependent lesions until proved otherwise; PGE1 infusion, by maintaining patency of the ductus arteriosus, is life-saving in such infants.

Clinical Summary

Infective endocarditis (IE), may be classified as acute or subacute or as native valve endocarditis, prosthetic valve endocarditis, or endocarditis in intravenous drug abusers. Gram-positive cocci account for 90% of culture-positive endocarditis; about 5% to 7% of cases are culture-negative. Etiologic agents include Streptococcus viridans (most common in all age groups), Staphylococcus aureus (second most common) followed by coagulase-negative S epidermidis, Enterococcus species, Streptococcus pneumoniae, HACEK group (Haemophilus species, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae) and Fungi (Candida species, Aspergillus species). Endocarditis in childhood is seen with preexisting CHD and includes patients with complex cyanotic congenital heart disease (eg, tetralogy of Fallot), post–cardiac surgery (eg, palliative shunt procedures) and patients with a previous history of endocarditis. Endocarditis can also occur without underlying CHD; predisposing factors include infected indwelling central venous catheters. Intravenous drug abuse is not a common predisposing factor in younger children. Bacteremia may occur during severe burns, any bacterial infection (eg, cellulitis, pneumonia, urinary tract infection), or following any dental or surgical procedures, any instrumentation of mucosal surfaces, or spontaneously following activities such as brushing teeth. Clinical features of IE are mentioned in Table 5.16. The Duke criteria (refer to American Heart Association website) are a combination of major and minor criteria that help in arriving at the diagnosis of IE. Differential diagnosis of IE includes malignancy, collagen vascular diseases, and other infections affecting the heart (eg, acute rheumatic fever).

Emergency Department Treatment and Disposition

Admit all patients with suspected IE for confirmation of the diagnosis, IV antibiotic therapy, and continuous cardiac monitoring and critical care in those who are acutely ill. Blood cultures is the gold standard for diagnosis and is positive in >95% of cases. Take at least three sets of blood cultures from separate venipuncture sites with as large a quantity of blood as possible. Obtain CBC (normocytic normochromic anemia, leukocytosis), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and urinalysis (microscopic hematuria, proteinuria). Antibiotic therapy (2–6 weeks in duration) should be guided by the identification of the pathogen and sensitivity and it is best not to administer antibiotics in the ED while awaiting culture results. Duration of therapy varies from 2 to 6 weeks.

Pearls

1. Suspect endocarditis in any patient with a heart murmur and persistent unexplained high fever, especially with underlying CHD or condition that increases the risk of bacteremia, or in any febrile IV drug abuser (even in the absence of a heart murmur).

2. Patients with CHD presenting to the ED with evidence of soft tissue infections (eg, abscess) must receive appropriate antibiotic coverage prior to débridement or incision and drainage.

Clinical Summary

Acute pericarditis, an acute inflammation of the parietal and visceral surfaces of the pericardium, may be infectious or noninfectious and can be associated with pericardial effusion. Viral infections are the most common etiology, particularly in infancy (eg, Coxsackie B virus, Adenovirus, enteroviruses, echoviruses, cytomegalovirus, HIV, influenza virus). Other etiologies include but are not limited to acute rheumatic fever, purulent pericarditis (eg, S aureus, S pneumoniae, Haemophilus influenzae, Neisseria meningitides, and streptococci), tuberculosis (constrictive pericarditis), heart surgery (postpericardiotomy syndrome), collagen vascular diseases (eg, rheumatoid arthritis), and uremia (uremic pericarditis). Pericardial effusion may be sero-fibrinous, hemorrhagic, or purulent. Effusion may be completely absorbed or may result in pericardial thickening or chronic constriction (constrictive pericarditis). A rapid accumulation of a large amount of fluid produces cardiac tamponade that is classically associated with a triad of low arterial blood pressure, jugular venous distention, and distant, muffled heart sounds (Beck triad). Narrowed pulse pressure and pulsus paradoxus may be observed. Cardiac tamponade occurs more commonly with purulent pericarditis.

History may reveal preceding upper respiratory tract infection. Fever and chest pain may be present. Chest pain may be relieved by leaning forward and may be made worse by supine position or deep inspiration. Pericardial friction rub (a grating to-and-fro sound in phase with the heart sounds) is the cardinal physical sign. Heart murmur is usually absent. Presence of a cardiac murmur should alert the consideration of acute rheumatic fever or endocarditis.

Emergency Department Treatment and Disposition

Obtain ECG, chest radiograph, and cardiology consult. ECG reveals low-voltage QRS complex (caused by pericardial effusion) and diffuse ST-segment elevation in all precordial and limb leads. Chest radiograph will show varying degrees of cardiomegaly and increased pulmonary vascular markings (with cardiac tamponade). Echocardiography is most useful to diagnose pericardial effusion.

Stabilize patients with hemodynamic compromise. For cardiac tamponade, perform urgent decompression by surgical drainage or pericardiocentesis. Give fluid boluses with Plasmanate to increase central venous pressure and improve cardiac filling, which can provide temporary emergency stabilization. Admit patients with hemodynamic compromise or expected to have progressive disease to the ICU. Give salicylates for precordial pain and rheumatic pericarditis. Corticosteroid therapy may be indicated in severe rheumatic carditis or postpericardiotomy syndrome. For viral pericarditis there is no specific treatment; pericardiocentesis or surgical drainage is mandatory to identify the cause of pericarditis, especially when purulent or tuberculous pericarditis is suspected. A drainage catheter may be left in place.

Pearls

1. Viral infection is the most common cause of acute pericarditis. A history of upper respiratory tract infection along with a symptom of chest pain that is relieved on leaning forward is helpful in making a diagnosis.

2. Most serious complication of pericarditis is pericardial effusion and cardiac tamponade, the presence of which is an indication for urgent pericardiocentesis.

Clinical Summary

Acute myocarditis is caused by acute inflammation of the myocardium and may be infectious or noninfectious in origin. Viral infection is the most common cause, and pathogens include Coxsackie virus B, Adenovirus, enteroviruses, echoviruses, cytomegalovirus, HIV, and influenza. Rarely, bacteria, rickettsia, fungi, protozoa, and parasites are the causative agents. Other etiologies include immune-mediated diseases (eg, acute rheumatic fever, Kawasaki disease, collagen vascular diseases) and toxic myocarditis (eg, drug ingestion, diphtheria exotoxin).

Older children may have a history of preceding upper respiratory tract or gastrointestinal infection. The illness may have a sudden onset in newborns and small infants with anorexia, vomiting, lethargy, respiratory distress, and circulatory shock. Arrhythmias including supraventricular tachycardia or ventricular ectopic beats may be audible. The mortality rate is as high as 75% in symptomatic neonates with acute viral myocarditis although the majority of patients with mild disease recover completely. Some patients develop subacute or chronic myocarditis with persistent cardiomegaly and congestive heart failure.

Emergency Department Treatment and Disposition

Obtain ECG, chest radiography, and consult cardiology. Cardiomegaly of varying degrees is seen on chest x-ray. ECG reveals low-voltage QRS complex, ST-T changes, QT prolongation, and arrhythmias, especially premature ventricular contractions. Echocardiography reveals cardiac chamber enlargement and impaired left ventricle function. Occasionally, a thrombus in the left ventricle can be found. Cardiac troponin levels and MB isoenzyme of creatine kinase may be elevated. Endomyocardial biopsy is the best confirmatory test though not practical in every situation.

Admit hemodynamically unstable patients and those with aggressive arrhythmias to ICU. Attempt virus identification by viral cultures from the blood, stool, or throat washing. Bed rest and limitation of activity is recommended during the acute phase. Treat arrhythmias aggressively. When the clinical diagnosis of myocarditis is suspected, it is now recommended to treat with high-dose IV γ-globulin in the hospital.

Pearls

1. Myocarditis severe enough to be recognized clinically is rare; mild and subclinical cases are more prevalent.

2. Maintain a high index of suspicion as there is a high mortality rate, especially in childhood.

3. Acute myocarditis results in aggressive arrhythmias that may be hard to treat.

Clinical Summary

Acute rheumatic fever (ARF) is an immunogenic multisystem disease that occurs as a delayed sequel of group A streptococcal infection of the pharynx but not the skin. Important predisposing factors include family history of ARF, low socioeconomic status, and age between 6 and 15 years. ARF is diagnosed by the use of revised Jones criteria. History of streptococcal pharyngitis is commonly present 1 to 5 weeks before the onset of symptoms or may be as long as 2 to 6 months in case of isolated chorea.

Arthritis is the most common manifestation usually involving large joints either simultaneously or in succession with a characteristic migratory nature. Signs of carditis include (in increasing order of severity) tachycardia out of proportion to the degree of fever, a heart murmur of valvulitis caused by mitral or aortic valve regurgitation, pericarditis (friction rub, pericardial effusion, ECG changes), or signs of congestive heart failure (severe carditis). Erythema marginatum is characterized by nonpruritic serpiginous or annular erythematous rashes most prominent on the trunk and the inner proximal portions of the extremities but never on the face. Subcutaneous nodules are hard, painless, nonpruritic, freely mobile swellings of 0.2 to 2 cm in diameter found symmetrically, singly or in clusters, on the extensor surfaces of both large and small joints, over the scalp, or along the spine.

Sydenham chorea (St. Vitus dance) is more common in prepubertal girls and can be the only manifestation of ARF. It is a neuropsychiatric disorder consisting of both neurologic signs (choreic movement and hypotonia) and psychiatric signs (emotional lability, hyperactivity, separation anxiety, obsessions, and compulsions).

Laboratory evidence of elevated ESR and CRP are objective evidence of an inflammatory process. Positive throat culture or rapid streptococcal antigen tests are less reliable than antibody tests. Antibody tests include ASO titer, anti-DNAase B, and the Streptozyme test. Nonspecific symptoms include abdominal pain, rapid sleeping heart rate, malaise, anemia, epistaxis, and precordial pain. The differential includes juvenile rheumatoid arthritis, systemic lupus erythematosus, mixed connective tissue disorder, reactive arthritis, serum sickness, infectious arthritis, and hematologic disorders such as leukemia. Only carditis causes permanent cardiac damage.

Emergency Department Treatment and Disposition

Evaluate hemodynamic status and stabilize as indicated including the use of high-flow oxygen, continuous cardiac, blood pressure, and pulse oximetry monitoring. Admit patients for further workup and management when a diagnosis of ARF is made or clinically suspected. Consult cardiology for echocardiography in patients with a murmur to diagnose the severity of carditis. Antibiotics to eradicate streptococci (eg, benzathine penicillin G given IM to patients not allergic to penicillin) and anti-inflammatory therapies (eg, salicylates and steroids) are the mainstay of therapy but should not be started until a definite diagnosis is made.

Pearls

1. The revised Jones criteria are used for the diagnosis of ARF.

2. Maintain a high index of clinical suspicion for ARF as it is uncommon in the United States and it must be differentiated from other rheumatologic conditions.

Clinical Summary

Acute or chronic pain in the precordial region that could radiate to the neck, arm, or jaw associated with nausea and typically precipitated by exercise is a common presenting symptom in the ED. Relative frequency and causes in children are listed in Table 5.18.

The initial history should be directed at determining the nature of pain, associated symptoms, and concurrent or precipitating events that may help clarify the noncardiac origin of the pain, including focusing on important past and family histories. Before turning the focus to the chest, perform a through physical examination, including observations whether the child is in severe distress from pain, in emotional stress, or hyperventilating. A typical angina pain is located in the precordial or substernal area and radiates to the neck, jaw, arms, back, or abdomen. Patient describes pain as a deep, heavy pressure; the feeling of choking; or a squeezing sensation. Exercise, cold stress, emotional upset, or a large meal typically precipitates angina pain.

Emergency Department Treatment and Disposition

A three-step diagnostic approach is recommended. First, look for the three most common causes of chest pain: costochondritis, musculoskeletal causes, and respiratory diseases. Next, check for cardiac causes, with cardiac exam, chest x-ray, and ECG, if clinically indicated. Last, if a cardiac cause is not found, look for disease in other systems, including psychogenic and idiopathic causes.

Direct treatment at correcting or improving the cause once a specific cause of chest pain is identified. Consult cardiology when chest pain is anginal or there are any abnormal findings in chest x-ray or ECG, with a positive family history for cardiomyopathy, LQTS, or another hereditary disease associated with cardiac abnormalities. Cardiac evaluation requires further studies such as echo, exercise stress test, Holter monitoring, or even cardiac catheterization and, depending on the cause, treatment will be medical or surgical. Most musculoskeletal and nonorganic causes of chest pain can be treated with rest, acetaminophen, or nonsteroidal anti-inflammatory agents. If respiratory causes of chest pain are found, treatment is directed at those causes.

Pearls

1. Chest pain is often benign in children. No cause can be found in a majority of patients, even after a moderately extensive investigation.

2. History is the most important; most cases of chest pain in children originate in organ systems other than the cardiovascular system.

3. Chest pain in children <12 years of age usually has a cardiorespiratory cause; psychogenic causes are more likely in children >12 years of age.

4. ED physicians should make every effort to find a specific cause before making a referral to a specialist or reassuring the child and the parents of the benign nature of the complaint.

Clinical Summary

In congestive heart failure (CHF), the heart is unable to pump enough blood to the body to meet its needs. CHF may result from congenital or acquired heart diseases with volume or pressure overload or from myocardial insufficiency. Volume overload lesions like a ventricular septal defect (VSD); patent ductus arteriosus (PDA); atrioventricular septal defects (AV canal), and systemic arteriovenous fistula are the most common causes of CHF in the first 6 months of life. Large left-to-right shunts do not cause CHF before 6 to 8 weeks of age because the pulmonary vascular resistance does not fall low enough to cause a large shunt until this age. Atrial septal defect rarely causes CHF, and children with cyanotic heart diseases do not develop CHF unless they have a large systemic-to-pulmonary artery shunt like a VSD, PDA, or a surgical shunt. Pulmonary venous congestion in left-sided heart failure leads to tachypnea, dyspnea with exertion, poor feeding, orthopnea in older children, and wheezing and pulmonary crackles. Systemic venous congestion in right-sided heart failure results in hepatomegaly and periorbital edema. Tachycardia, gallop rhythm, and a weak, thready pulse are common findings. Distended neck veins and ankle edema may be seen in older children, but are not seen in infants. Splenomegaly is not indicative of chronic CHF.

Emergency Department Treatment and Disposition

Obtain ECG and chest radiograph and consult a cardiologist. Cardiomegaly is almost always present on chest x-ray, often with increased pulmonary vascular markings. ECG may help determine the type of defect but is not helpful in deciding whether CHF is present. Echocardiogram reveals cardiac chamber enlargement and impaired left ventricle function and may help determine the cause of CHF. Hospitalize patients presenting in acute or chronic decompensated heart failure with hemodynamic compromise for inpatient therapy to bring CHF back to a compensated state.

Management of CHF consists of elimination of underlying causes (eg, VSD), elimination of predisposing or contributing causes (eg, anemia, arrhythmia, infection) and control of heart failure. In the ED, a heart failure state can be controlled by the use of multiple drugs, usually inotropes, diuretics, and afterload-reducing agents along with general supportive measures. A cardiac chair or infant seat is used to relieve respiratory distress. Oxygen with humidity is used in infants with respiratory distress but care must be taken if a congenital heart disease is suspected, as oxygen may increase the shunt and make CHF worse.

Pearls

1. CHF may result from congenital or acquired heart diseases; knowing the etiologies at various age groups may provide clues for making the proper diagnosis.

2. Signs and symptoms of CHF are different in infants and older children. Infants present with poor feeding of recent onset, tachypnea that worsens during feeding, poor weight gain, and cold sweat on the forehead. Older children may complain of shortness of breath, especially with activity, easy fatigability, puffy eyelids, or swollen feet.

3. Cardiomegaly on chest radiograph is nearly a prerequisite sign of CHF.