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Cardiodromes: Using recognizable sets of signs & symptoms to understand & manage congenital heart defects


JEMS Clinical Review Features

This clinical review feature article is presented in conjunction with the Department of Emergency Medicine Education at the University of Texas Southwestern Medical Center, Dallas.

Learning Objectives

>>„Identify and discuss four cardiodromes that can be used to classify congenital heart defects.„

>>„Identify the proper assessment for patients with congenital heart defects.

>>„Identify common complications and management for patients with congenital heart defects.

>>„Recognize subtle presentations for patients with congenital heart defects.

Glossary Terms

A recognizable pattern or syndrome associated with the heart; a related set of signs and symptoms associated with the heart.

Congenital heart defect (CHD):Defects of the heart_s structures and blood vessels present at birth.

Dysmorphic:A physical characteristic that is abnormally formed.„Hypoplastic left heart syndrome:„A CHD in which the left side of the heart and its structures are underdeveloped.

Polycythemia:An increased number of red blood cells; this can be a primary finding or may occur secondary to low oxygen levels associated with heart and lung diseases.

Pulmonary hypertension:Abnormally high pressure within the pulmonary circulation.

Tetralogy of Fallot:A CHD characterized by four malformations: pulmonary stenosis, ventricular septal defect, malposition of the aorta (overrides both the left and right sides of the heart), and hypertrophy of the right ventricle.

Case Study

You respond to a ball park for a report of "a person down" on the field. You arrive to find a 21-year-old male who presents with shortness of breath and palpitations. Your assessment reveals that he_s awake and alert, tachypneic at 28 bpm, and pale, cool and diaphoretic. The patient_s radial pulse is weak and thready on palpation. The monitor reveals a supraventricular tachycardia (SVT) at a rate of 178, blood pressure of 88/42 and SpO of 88%. Lung sounds reveal fine crackles„at the bases, and abnormal heart sounds are heard on auscultation.„

History reveals the patient had heart surgery when he was two years old and had to see a cardiologist when he was younger, but he does not know why. He last saw his cardiologist when he was 16.„

As you prepare for synchronized cardioversion, the patient attempts a vagal maneuver without success. He is then cardioverted with 50 joules without effect. Subsequent attempts also fail to convert his dysrhythmia, leaving his HR at 194.„

Your base station physician advises you to transport the patient to a local hospital 11 minutes away from the park. The patient is transported with 100% oxygen via non-rebreather and an IV TKO. On arrival at the emergency department (ED), the patient is administered adenosine with no changes in his cardiac status.


Every year, 35,000 babies are born with acongenital heart defect„(CHD).This represents eight out of every 1,000 children. They may have one defect or several abnormalities involving the chambers, valves or„

blood vessels. Some defects are mild and easily repaired, whereas others are life-threatening, either immediately or over time.„

The good news is that many patients with CHDs that were once considered uniformly fatal during infancy are now living well into adulthood. It_s estimated that 400,000 adults currently have a CHD. The bad news is that only a handful of adult cardiologists focus specifically on the care of adult CHD (ACHD) patients, even though 8,500Ï9,000 CHD patients turn 18 every year, and half of all CHD patients will require significant medical intervention for their condition at some point in their adult life.„

CHDs are a significant cause of death in both pediatric and adult populations. It has been well established that most infant deaths in the U.S. are caused by congenital cardiovascular defects. Older children and adults with cardiovascular defects usually die from a complication of their condition, typically the result of defect-induced cardiac ischemia, dysrhythmia, sepsis orpulmonary hypertension, often leading to sudden death or progressive heart failure.„

For some conditions, death due to complications occurs at an average age of 37. Adults with CHD may also have other organ problems that complicate their care. With the large number of children with these defects, and the growing numbers of ACHD patients, there_s an increasing need for emergency responders to understand CHDs and the different effects they have on pediatric and adult populations. They should become familiar with the most common defects and be armed with the knowledge that enables them to properly assess and treat all patients, regardless of the complexity of their defect.

Classification of CHDs

There are more than 15 classified CHDs, each with its own anatomic variations. This broad range can make assessment and diagnosis difficult, especially in the emergency environment. For this reason, several attempts at broad classification of CHDs have been made.„

The classical approach involves using the physical characteristic of cyanosis to either classify patients as cyanotic or acyanotic. Although this approach is conceptually useful for identifying types of circulatory problems, it_s unreliable in terms of actual patient presentation. An example would be a patient with a cyanotic-type defect who presents with normal skin color because of increased production of red blood cells that occurs as a compensatory mechanism for persistent hypoxemia (compensatorypolycythemia).

A more accurate assessment approach would be to determine blood flow patterns and whether the condition causes pulmonary blood flow to be increased or decreased, leads to ventricular outflow obstructions, or creates mixed blood flow patterns. However, this model does not offer an easy way to assess and manage CHD patients as a whole. This makes it relatively useless in the prehospital setting, where it_s often impossible to determine defect type.„

A field-appropriate approach to classifying clinical presentations may be the use ofcardiodromes.These recognizable patterns or categories can offer management guidelines regardless of defect, facilitating the assessment and treatment of patients. This is conceptually similar to the use of toxidromes in the management of patients with toxic exposures. In the case of toxidromes, the toxins involved may be difficult to determine, but patient presentation dictates the type of exposure and, therefore, the management necessary. Similarly, patients with CHDs will have only a handful of presenting signs and symptoms, although the list of possible defects that caused these complications may be long.„

There are essentially four cardiodromes for CHDs that are useful for patient management, and they can be remembered using the mnemonic CHDS: C = congestive heart failure (CHF), H = hypoxemic, D = ductal-dependant cardiogenic shock (DDCS), and S = survivors cardiodromes.Table 1summarizes the characteristics of each.„

Initial Assessment

Field management of patients with CHDs relies on recognizing the patient_s condition, providing correct interventions and rapidly transporting to appropriate facilities for further evaluation and treatment. To appropriately manage these patients, emergency providers must understand the CHD patient_s presentations, which may be atypical.„

Patients with severe problems can appear to be in minor or no distress, but all symptoms should be documented, even if they appear benign. Because CHDs are often repaired in stages, infants between corrective surgeries may be best treated when vague symptoms are assumed to represent a serious problem. Five to 15% of these infants will die, and of the patients who are symptomatic, symptoms are often vague, including upper airway congestion, decreased feeding and irritability. Further, rapid deterioration of the CHD patient is not uncommon. Thus, good documentation, early recognition and transport are essential.„

The general appearance of the patient may assist in determining what underlying conditions can be present. Approximately 30% of neonates with a CHD have some other associated genetic defect, such as Down syndrome. Providers should always consider the possibility of cardiac involvement in patients who have observabledysmorphicfeatures.„

The CHD patient may have pale or mottled skin when compensating for decreased cardiac output. Cyanosis may or may not be present. "Cyanotic lesions" can appear on patients who have right ventricular outflow tract obstruction or decreased pulmonary blood flow, such ashypoplastic left heart syndromeorTetralogy of Fallot.Patients may develop polycythemia from prolonged tissue hypoxia (or delayed cord clamping after birth) and may not show obvious signs of cyanosis.„

It takes a reduction of 3 g/dL of hemoglobin before the patient becomes cyanotic, which means that SpO readings can be as low as 60% before cyanosis is present. Assessment of mucus membranes is a„

good way to assess for cyanosis.„

Patients with Tetralogy of Fallot may have "tet," or hypercyanotic, spells that cause excessive tachypnea and diaphoresis because of a sudden spasm within the right ventricle. Also, diaphoresis may be present as a result of increased catecholamine release, which happens because of increased sympathetic activity during compensation of decreased cardiac output.„

EMS providers should be especially concerned by a child or adult CHD patient who experiences a syncopal episode, because research suggests it_s predictive of imminent death. Also, poor feeding in infants is often associated with a ductal lesion,„which interferes with circulation to thelungs. Patients with ductal lesions are typically fatigued and have minimal energy„to be able to take in enough calories for growth. This fatigue often accompanies hypoxemia and poor oxygen delivery. Reports from parents and other caretakers may reveal periods of restlessness or irritability, which can occur from decreased cardiac output, hypoxemia or chest pain in a neonate or infant.

Signs of CHF are common, particularly peripheral edema. Patients may have symptoms of pulmonary hypertension, such as dyspnea, palpitations, chest pain, syncope and signs of CHF.

The wide variation in presentations related to severe reduction in cardiac output means the prehospital provider should be sure their assessment is thorough. In addition to documenting associated signs and symptoms, obtaining a history will greatly assist the receiving hospital in determining their course of treatment. Inquire about surgeries, especially in the first few months of life, such as whether the surgery was part of a series, and if so, whether that series was completed. Current medication regimens will also assist in the CHD diagnosis.„

If you suspect CHD, ask about current or recent antibiotic therapy. Because of the high risk for these patients developing bacterial endocarditis, you shouldn_t assume the chief complaint is going to be related to a valve, muscle or vessel. Also ask about dental and other minor procedures, fever and chills.

Remember, CHD symptoms and complications can be difficult for a caregiver who_s already under stress from their child_s primary condition. Look for signs that might indicate abuse, which is more common in„

the chronic-care child.

Measuring Vital Signs

During the physical exam, lung sounds should be auscultated early. Crackles heard at the bases may indicate the presence of pulmonary edema. If conditions allow, the prehospital provider should auscultate heart sounds. Abnormal heart sounds may or may not be present, especially in postductal lesions. The presence of a heart murmur could indicate possible fluid overload or heart-valve insufficiency, found in several CHDs. However, a heart murmur alone may be a benign sign in neonates, so assessment of additional abnormalities is essential.„

Assess for signs of increased work of breathing, such as retractions, grunting and nasal flaring. Patients with increased respiratory effort generally have a primary„respiratory problem, whereas those with effortless tachypnea are typically compensating for decreased cardiac output.

A blood pressure reading should be obtained on all four extremities of the CHD patient. If the readings are higher in the upper extremities, suspect possible coarctation of the aorta. This congenital constriction of the aorta impedes blood flow below the level of the constriction and increases blood pressure above it. Blood flow distal to the constriction is diminished, causing decreased perfusion to the lower extremities, claudication(cramping in the calves secondary to decreased blood flow), cold feet, and lower blood pressure in the legs than arms. Above the constriction, blood pressure is higher than in the legs, causing headaches and nosebleeds.„

Deformities of the heart also alter electrical conduction pathways. Apply the ECG to all patients who have, or are suspected of having, a CHD. Although these patients are often predisposed to SVT, some are predisposed to AV blocks, and third-degree blocks are poorly tolerated in the CHD patient.

One of the most common findings in the ECG is a new onset dysrhythmia. These patients often have abnormal readings depending on their type of congenital defect. These dysrhythmias may be attributed to scar formation at the surgical site, the underlying cardiac defect itself, or secondary conditions (e.g., chamber enlargement). The most common dysrhythmia associated with CHDs is SVT. Patients may present with new onset SVT and have sustained this rhythm for several days before becoming symptomatic. Right axis deviation and bundle branch blocks are also not uncommon. Sudden cardiac death from ventricular tachycardia is less prevalent, but does occur.

Pulse oximetry is an important tool for assessing patients with CHDs. Not only does it identify those with low SpO, current research also supports its use in screening„for severe CHDs in newborns. This research suggests that a newborn with a confirmed SpO less than 95% needs further evaluation to rule out a complex CHD. Patients who have hypoplastic left heart syndrome, Tetralogy of Fallot after an incomplete surgical intervention, or tricuspid atresia, typically have low pulse oximetry readings. Following the application of a few minutes of 100% oxygen, the provider will notice a major difference between the lung disease patient and CHD patient. The former will show improved skin signs and an SpO reading that approaches 100%. The CHD patient will remain cyanotic and have minimal improvement in his SpO readings.


The most important treatment step that can be made is to recognize that seemingly minor problems should be treated as though they_re serious. After this, prehospital care of patients with CHD is mainly supportive. Patients should be placed on supplemental oxygen and IV access should be obtained.„

In the case of a CHF type presentation, treatment should be aimed at reducing the consequences of fluid overload and follow the ordinary treatment regimen for heart failure. Treatment should include placing the patient in a Fowler_s or high Fowler_s position to reduce the consequences of pulmonary edema on breathing. Patients should be placed on high-flow oxygen„with consideration given to CPAP or endotracheal intubation depending on the„severity of the dyspnea. Nitroglycerin should be administered to adults to help reduce ventricular preload and, therefore, help clear the pulmonary edema. Morphine can be administered for discomfort (and arguably for potentially beneficial hemodynamic effects). Lasix can be administered to help reduce overall fluid volume and preload, also resulting in a reduction of pulmonary or systemic edema. Finally, a loss in cardiac contractility may occur in patients with chronic consequences of their heart defect and may be prescribed, or acutely require an inotrope, such as Digoxin, to improve their cardiac output.„

For hypoxemic patients, management is mainly supportive. With a patient history indicative of a "tet" spell, placing the patient in a knee-chest position and administering morphine sulfate may help end the episode. It_s also important for the health-care provider to understand that the administration of high-flow O is beneficial to the patient, although no changes in the patient_s SpO level or cyanotic appearance may be seen.„

Ductal dependant lesions need immediate administration of Prostaglandin E1, which is traditionally given in hospital. Field management is supportive with rapid transport.„

In CHD survivors with arrhythmic presentations, EMS providers should recognize that, due to sinus node dysfunction, there are challenges regarding the effectiveness of anti-dysrhythmic drugs. Additionally, pacing may be a problem due to changes in cardiac anatomy. Therefore, our traditional methods of treatment may„be ineffective.„

Also, increased survival rates of patients with a CHD means an increase in the number of pregnant women who have a CHD. In some patients, this represents a risk of problems associated with volume shifts and cardiac compromise in the mother and genetic and cardiovascular problems in the infant that may present on delivery. In one study of pregnant patients with cyanotic CHDs, many experienced cardiovascular complications, and almost half of the pregnancies resulted in live births. A slight majority of these„pregnancies resulted in spontaneous abortions. Therefore, all pregnant ACHD patients who are experiencing problems should be transported to an ED capable of caring for their condition.„

Case Wrap up

Because other treatments failed, a cardiologist orders morphine, which improves the patient_s oxygen saturation and reduces his symptomology. The patient is prepared for surgery for pulmonary valve repair. His diagnosis is pulmonary regurgitation. The patient_s history included repair of Tetralogy of Fallot at two years old.


Patients with repaired CHDs are living longer, posing new challenges for prehospital providers. When responding to emergencies involving CHD patients, field providers must remember that ACHD symptoms often don_t become apparent until a person is in their 40s and that long-term complications of some cardiac-defect repairs may present atypically. Because classical assessment tools for heart failure have not been linked to CHD patients, categorizing CHDs in clinical cardiodromes may assist in identifying what type of condition is present and guide management.JEMS

James F. Goss,MHA, MICP, is program director and lead paramedic instructor for NCTI in Riverside, Calif. He_s also assistant professor of emergency medical care at Loma Linda University in Loma Linda, Calif., and a frequent contributor to JEMS. Contact him atjgoss@llu.edu.

CarrieCobos,BS, RN, CEN, CFRN, is an EMS educator for the Los Angeles Fire Department, an emergency nurse at Loma Linda University Medical Center, and a graduate of the Loma Linda University Emergency Medical Care (EMC) program.„

Sevan Gerard,BS, MICP, is a firefighter/paramedic with the Los Angeles Fire Department and a graduate of the Loma Linda University Emergency Medical Care program.

Cynthia Navis,MICP, is a Los Angeles-based paramedic and an EMS educator for the National College of Technical Instruction.„

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