Chapter 1
Tools to diagnose cardiac conditions in children

• History
  • General principles of the cardiovascular history
  • Chief complaint and/or presenting sign
• Physical examination
  • Vital signs
  • Cardiac examination
  • Percussion
  • Abdominal examination
• Laboratory examination
  • Electrocardiography
  • Chest X‐ray
  • Pulse oximetry
  • Blood counts
  • Echocardiography
  • Magnetic resonance imaging and angiography
  • Computed tomography
  • Cardiac catheterization
  • Exercise testing
• Additional reading

Much of the information presented in this chapter relates best to older infants and children. Diagnosis in newborn infants is more difficult, because the patient may be very ill and in need of an urgent diagnosis for prompt treatment. In this age group, echocardiography is often the initial diagnostic method. The unique challenges in newborns are discussed in Chapter 8.

The history and physical examination are the keystones for diagnosis of cardiac problems. A variety of other diagnostic techniques can be employed beyond the history and physical examination. With each technique, different aspects of the cardiovascular system are viewed, and by combining the data derived, an accurate assessment of the patient's condition can be obtained.

HISTORY

General principles of the cardiovascular history

The suspicion of a cardiovascular abnormality may be raised initially by specific symptoms, but more commonly the presenting feature is the discovery of a cardiac murmur. Many children with a cardiac abnormality are asymptomatic because the malformation does not result in major hemodynamic alterations. Even with a significant cardiac problem, the child may be asymptomatic because the myocardium is capable of responding normally to the stresses placed upon it by the altered hemodynamics. A comparable lesion in an adult might produce symptoms because of coexistent coronary arterial disease or myocardial fibrosis.

In obtaining the history of a child suspected of cardiac disease, one seeks three types of data: those suggesting a diagnosis, assessment of severity, and the etiology of the condition.

Diagnostic clues

Diagnostic clues and other more general factors include the following.

Gender. Certain cardiac malformations have a definite gender predominance. Atrial septal defect (ASD) and patent ductus arteriosus (PDA) are two to three times more likely in female than in male children. Coarctation of the aorta, aortic stenosis, and transposition of the great arteries occur more commonly in male children.

Age. The age at which a cardiac murmur or a symptom develops may give a diagnostic clue. The murmurs of congenital aortic stenosis and pulmonary stenosis are often heard on the first examination after birth. Ventricular septal defect (VSD) is usually first recognized because of symptoms and murmur at two weeks of age. The murmur of an ASD may not be discovered until the preschool examination. A functional (innocent) murmur is found in at least half of school‐age children.

Severity of the cardiac condition

Information that suggests the condition's severity (e.g. dyspnea or fatigue) should be sought.

Etiology

The examiner should seek information that suggests an etiology of cardiac condition (e.g. maternal lupus).

Chief complaint and/or presenting sign

Certain presenting complaints and signs are more common in particular cardiac disorders and the “index of suspicion” aids the medical professional in organizing the data to make a differential diagnosis. For many of the signs and symptoms discussed later, noncardiac causes are often more likely than cardiac causes (e.g. acute dyspnea in a previously healthy four‐month‐old infant with no murmur is more likely a result of bronchiolitis than of congestive heart failure). Therefore, a complete history must be integrated with the physical examination and other diagnostic studies to arrive at the correct cardiac diagnosis.

The most common symptoms or signs found in an outpatient setting are murmur, chest pain, palpitations, and near‐syncope (fainting).

Murmur

Murmur is the most common presenting finding because virtually all children and adults with a normal heart have an innocent (normal) murmur sometime during their lifetime. Certain features are associated with an innocent murmur; the child is asymptomatic and murmurs appearing after infancy tend to be innocent. The murmur of ASD is one important exception.

Chest pain

Chest pain is a common and benign symptom in older children and adolescents, estimated to occur at some time in 70% of school‐aged children. About 1 in 200 visits to a pediatric emergency room is for chest pain.

Chest pain rarely occurs with cardiovascular disease during childhood. Myocardial ischemic syndromes (e.g. Kawasaki disease with coronary artery aneurysms; hypertrophic cardiomyopathy) may lead to true angina. Patients with connective tissue disorders (e.g. Marfan syndrome) may have chest (or back) pain from aortic dissection. Although pericarditis may cause chest pain, it is almost always associated with fever and other signs of inflammation. Occasionally, chest pain accompanies supraventricular tachycardia. Most children with congenital cardiac malformations, including those who are fully recovered from surgery, do not have chest pain, and most children and adolescents who present with chest pain as their chief complaint do not have a cardiac malformation or disease.

Most chest pain is benign. It is usually transient, appearing abruptly, lasting from 30 seconds to five minutes, and localized to the parasternal area. It is distinguished from angina by the absence of diaphoresis, nausea, emesis, and paresthesias in an ulnar distribution. Benign chest pain is typically well localized, sharp in character (not “crushing” like angina), short in duration (seconds to minutes), often aggravated by certain positions or movements, and occasionally can be induced by palpation over the area. Benign chest pain may also occur as a result of chest wall tenderness. These characteristics are strong evidence against cardiac cause for the pain. Some noncardiac conditions (e.g. asthma) may be associated with childhood chest pain. Benign pain is often described as “functional” because an organic cause cannot be found.

Palpitations

Palpitations, the sensation of irregular heartbeats, “skipped beats,” or, more commonly, rapid beats, are also common in the school‐aged child and adolescent. They frequently occur in patients with other symptoms, such as chest pain, but often not simultaneously with the other symptoms. Palpitations are often found to be associated with normal sinus rhythm when an electrocardiogram is monitored during the symptom. Palpitations are not usually present in patients with known premature beats. Palpitations of sudden onset (approximately the time span of a single beat) and sudden termination suggest tachyarrhythmia.

Syncope and orthostatic intolerance

Syncope is a sudden, brief loss of consciousness associated with loss of postural tone, with a spontaneous recovery. It is a common presenting symptom to the cardiology clinic, present in up to 15% of children, especially during the adolescent years. Life‐threatening etiologies are rare but possible, and, when present, are often cardiac in nature. Worrisome historical features, such as lack of any prodrome, occurrence during exercise, or antecedent strong palpitations necessitate a more extensive work‐up. Cardiac causes for syncope include electrical (i.e. long QT syndrome [LQTS], Brugada) and structural (hypertrophic cardiomyopathy, coronary anomalies, aortic stenosis, pulmonary hypertension) conditions. Further clues as to these diagnoses may come from the family history, which should be explored for sudden death, syncope, seizures, sudden infant death syndrome (SIDS), swimming deaths, and single‐occupant motor vehicle fatalities.

Despite the concern a syncopal episode often generates, benign etiologies are often the culprit, with vasovagal syncope being the most common pediatric diagnosis (>80% of pediatric syncope). Vasovagal syncope occurs when the autonomic nervous system overreacts to a trigger, such as dehydration, pain, or emotional upset, with the result being bradycardia and/or vasodilation and thus significant cerebral hypoperfusion, leading to loss of consciousness and tone. With a fall to the ground, gravity no longer hinders restoration of cerebral perfusion and the patient quickly reawakens. Further history obtained from these patients typically includes inadequate fluid and salt intake, preceding postural change or prolonged upright body position, and, importantly, prodromal dizziness prior to syncope. Frequent postural dizziness without syncope often also is present. When persistent and sufficiently distressing to the patient, this is referred to as orthostatic intolerance. Orthostatic intolerance is quite common in teenagers...