Cardiac EAQ
Electrocardiography (ECG) is scheduled for an infant who has tetralogy of Fallot. The mother asks the nurse what type of test this is and why it is done. What is the best response by the nurse?
"Electrical activity in the baby's heart is recorded, then printed on graph paper." Rationale: An ECG not only records electrical impulses in the heart but can also reveal atrial and ventricular hypertrophy. The x-ray procedure that shows the size of a baby's heart is a chest x-ray. The ultrasound procedure that would be used to produce images of the structures in a baby's heart is the echocardiogram. The intravenous injection of contrast material to visualize the flow of blood through the heart is an angiogram.
Which ECG report shows atrial fibrillation?
4 Rationale: Image 4 shows a wavy baseline with atrial electrical activity and an irregular ventricular rhythm which indicates atrial fibrillation. Image 1 shows normal sinus rhythm in which both atrial and ventricular rhythms are essentially regular. There is one P wave before each QRS complex, and all the P waves are of a consistent morphology or shape. Image 2 shows sinus tachycardia. Image 3 shows sinus bradycardia.
A nurse is assessing the ECG rhythm strip. The nurse checks the P wave. Which function of the heart is the nurse assessing?
Atrial depolarization Rationale: The P wave represents atrial depolarization. The QRS complex represents ventricular depolarization. Atrial repolarization also occurs simultaneously to ventricular depolarization, but because of the larger muscle mass of the ventricles, visualization of atrial repolarization is obscured by the QRS complex. The T wave represents ventricular repolarization.
A client presents to the emergency department with weakness, dizziness, and difficulty breathing. The nurse performs an electrocardiogram (ECG) and notices this arrhythmia. Which arrhythmia is the client exhibiting?
Atrial fibrillation (AF) Rationale: AF can be chronic or intermittent. Note the wavy baseline with uncoordinated atrial electrical activity and irregular ventricular rhythm. AF clients who have valvular disease are particularly at risk for venous thromboembolism (VTE). Symptoms depend upon the ventricular rate and, if rapid, the client can experience fatigue, weakness, shortness of breath, dizziness, anxiety, syncope, palpitations, chest discomfort, and hypotension. Clients should be monitored carefully for these complications. Some clients can be asymptomatic. VT is a rapid ventricular rate typically between 140 and 250 beats per min and characterized by wide bizarre QRS complexes. Clients exhibiting junctional tachycardia may have no P waves or inverted P waves and a rate greater than 100. SVT involves the rapid stimulation of atrial tissue at a rate of over 150 beats per min in adults. During SVT, P waves may not be visible, especially if there is a 1:1 conduction with rapid rates because the P waves are embedded in the preceding T wave. SVT may occur in healthy young people, especially women.
A client with a history of heart failure and hypertension is admitted with reports of syncope. Which prescribed medication should the nurse prepare to administer based on the electrocardiogram (ECG) rhythm strip image?
Atropine Rationale: This rhythm strip reflects sinus bradycardia. Sinus bradycardia has PQRST complexes within acceptable limits, but the rate is less than 60 beats per minute. In this strip the PR interval is 0.16, the rhythm is regular, and the rate is 40 beats per minute. Atropine, an anticholinergic that increases the heart rate, is administered when the heart rate is so slow that it causes symptoms. Digoxin is a cardiac glycoside that slows the heart rate. Enalapril is an angiotensin-converting enzyme (ACE) inhibitor that slows the heart rate. Metoprolol is a beta blocker that slows the heart rate.
A 3-year-old child with the diagnosis of tetralogy of Fallot is brought to the United States by a charitable organization for cardiac surgery. What should the nurse expect when conducting an admission assessment of the child?
Clubbing of Fingers Rationale: Hypoxia leads to poor peripheral circulation; clubbing occurs as a result of additional capillary development and tissue hypertrophy of the fingertips. A fever is not expected unless the child has an infection or is dehydrated; the data do not indicate this. The child's respiratory rate will be increased, not decreased. The child's problems are related to decreased oxygenation, not to a clotting deficiency.
A 2-year-old child who is hospitalized for repair of tetralogy of Fallot is seen squatting in the playroom. In response to this behavior, what should the nurse do?
Continue to observe the child if there are no other signs of distress. Rationale: Squatting is a physiologic adaptation for children with tetralogy of Fallot. By squatting, the child decreases the amount of arterial blood that is flowing to the extremities, which in turn decreases venous return to the heart and reduces preload.
The registered nurse is delegating tasks for nursing assistants caring for a client who requires more attention. Which element should be considered when selecting the suitable nursing assistant for delegation of a task?
Critical Thinking Rationale: Critical thinking is of utmost importance for selecting a suitable nursing assistant for delegation of a task in a situation where a client requires more attention, as the delegatee should be able to perform the task effectively. Time, safety, and stability are also the elements for effective delegation, but these are suitable depending on the situation for assigning a task and delegation.
What common finding can the nurse identify in most children with symptomatic cardiac malformations?
Delayed Physical Growth Rationale: Children with cardiac malformations often require more energy to fulfill the activities of daily living; decreased oxygen utilization and increased energy output in the developing child result in a slow growth rate. Mental retardation is not a common finding in children with congenital heart disease. Cardiac anomalies are more often a result of prenatal, rather than genetic, factors. Clubbing is not characteristic of most children with cardiac anomalies, only of those with more severe hypoxia.
A 1-year-old child has a congenital cardiac malformation that causes right-to-left shunting of blood through the heart. What clinical finding should the nurse expect?
Increased hematocrit Rationale: Polycythemia, reflected in an increased hematocrit reading, is a direct attempt by the body to compensate for the decrease in oxygen to all body cells caused by the mixture of oxygenated and deoxygenated circulating blood. Proteinuria is not a characteristic of heart malformations that cause right-to-left shunting of blood; nor is edema. An absence of pedal pulses is characteristic of coarctation of the aorta, an obstructive malformation.
Findings on a client's cardiac monitor indicate a need for an intravenous infusion that contains potassium for a client with hypokalemia. The nurse concludes that what finding on the monitor indicated a need for potassium replacement?
Lowering of the T wave Rationale: Hypokalemia causes a flattening of the T wave on an electrocardiogram, as observed on the monitor, because of its effect on muscle function. Hypokalemia causes a depression of the ST segment. Hypokalemia causes a widening of the QRS complex. Hypokalemia does not cause a deflection of the Q wave.
A nurse is assessing a client's ECG reading. The client's atrial and ventricular heart rates are equal at 88 beats per min. The PR interval is 0.14 seconds, and the QRS width is 0.10 seconds. Rhythm is regular with normal P waves and QRS complexes. How will the nurse interpret this rhythm?
Normal sinus rhythm Rationale: Normal sinus rhythm reflects normal conduction of the sinus impulse through the atria and ventricles. Atrial and ventricular rates are the same and range from 60 to 100 beats per minute. Rhythm is regular or essentially regular. PR interval is 0.12 to 0.20 seconds. QRS interval is 0.04 to 0.10 seconds. P and QRS waves are consistent in shape. Sinus tachycardia results when the sinoatrial (SA) node fires faster than 100 beats per minute. Bradycardia is defined as a heart rate less than 60 beats per minute. Sinus arrhythmia is a cyclical change in heart rate that is associated with respiration. The heart rate slightly increases during inspiration and slightly slows during exhalation because of changes in vagal tone.
A nurse is determining whether or not a client's atrial rhythm is regular when reviewing the ECG rhythm strip. Which consistency of spacing will the nurse use to determine regularity?
P waves Rationale: The P wave represents atrial contraction. Regularity is assessed by using electronic or physical calipers, or a piece of paper and pencil. To determine atrial regularity, identify the P wave and place one caliper point on the peak of the P wave. Locate the next P wave and place the second caliper point on its peak. The second point is left stationary, and the calipers are flipped over. If the first caliper point lands exactly on the next P wave, the atrial rhythm is perfectly regular. If the point lands one small box or less away from the next P wave, the rhythm is essentially regular. If the point lands more than one small box away, the rhythm is considered irregular. The same process can be performed with a simple piece of paper. Place the paper parallel and below the rhythm line, make a hatch mark below the first and second P waves, and then move the paper over to determine if the distance between the second and third P waves is equal to the first and second. When an atrial rhythm is perfectly regular, each P wave is an equal distance from the next P wave. This process is also used to assess ventricular regularity, except that the caliper points are placed on the peak of two consecutive R waves. QRS intervals can lengthen in response to new bundle branch blocks or with ventricular dysrhythmias.
A complete blood count is prescribed for a 5-month-old infant with tetralogy of Fallot. What does the nurse expect to see when reviewing the laboratory results?
Polycythemia Rationale: The body responds to the chronic hypoxia caused by the heart defect by increasing the production of red blood cells (RBCs) in an attempt to increase the oxygen-carrying capacity of the blood. The RBC count will be increased because the body increases erythrocyte production in an attempt to make more cells available to carry oxygen. Agranulocytosis does not result from hypoxia; it occurs when the white blood cell count decreases to a very low level and neutropenia becomes pronounced. Leukopenia occurs when the white blood cells become low and is not associated with tetralogy of Fallot.
Which serum laboratory values in a client with urinary problems may indicate the risk of developing muscle weakness and cardiac arrhythmias?
Potassium of 7.02 mEq/L (7.02 mmol/L) Rationale: The normal level of serum potassium is between 3.5-5.0 mEq/L (3.5 and 5.0 mmol/L). Elevated potassium levels greater than 6 mEq/L (mmol/L) can lead to muscle weakness and cardiac arrhythmias. The normal levels of serum phosphorus are between 2.4-4.4 mg/dL (0.78 and 1.42 mmol/L). The normal levels of serum calcium are usually between 8.6-10.2 mg/dL (2.15 and 2.55 mmol/L). The normal level of serum bicarbonate is between 22 and 26 mEq/L or mmol/L. These findings are not associated with the risk of developing muscle weakness and cardiac arrhythmias.
What should the nursing care of an 8-month-old infant with tetralogy of Fallot include?
Prevention of increased respiratory effort to promote oxygenation Rationale: Preventing respiratory distress minimizes the workload of the heart; this is accomplished with such interventions as positioning, maintaining diet restrictions, administering medications, and promoting conservation of energy. Restriction of fluid intake will promote hemoconcentration; if oral fluids are limited to conserve energy, intravenous fluids may be indicated. Additional iron intake will aggravate the polycythemia that results from hypoxia caused by reduced pulmonary blood flow. Administration of coagulants along with hemoconcentration is conducive to thrombus formation.
A nurse is assessing an ECG rhythm strip. Which component of the tracing will the nurse observe to determine ventricular depolarization?
QRS complex Rationale: The QRS complex represents ventricular depolarization. The classic QRS complex begins with a negative, or downward, deflection immediately after the PR interval. The P wave represents atrial depolarization. Normally a P wave indicates that the sinoatrial node initiated the impulse that depolarized the atrium. The T wave represents ventricular repolarization. The interval from the beginning of the P wave to the next deflection from the baseline is called the PR interval.
The client is experiencing fatigue, difficulty breathing, and dizziness. Which dysrhythmia does the nurse interpret from the cardiac monitor?
Sinus tachycardia Rationale: Sinus tachycardia is regular rhythm but at a rate higher than 100 beats per min. The client may experience shortness of breath, palpitation, fatigue, and dizziness. Atrial flutter (saw-tooth waves) arises from a conduction defect in the atrium resulting in a rapid atrial rate, usually between 200 to 350 times/minute. The atrial rate is faster than the atrioventricular (AV) node can conduct so that not all atrial impulses are conducted through to the ventricle. Sinus bradycardia is a regular rhythm but at a rate lower than 60 beats per minute. Atrial fibrillation is an irregular rhythm that is a result of multiple irritable foci firing in the atria and bombarding the AV node with irregular conduction of impulses through the node.
A client at 28 weeks' gestation with previously diagnosed mitral valve stenosis is being evaluated in the clinic. Which sign or symptom indicates that the client is experiencing cardiac difficulties?
Syncope on exertion Rationale: Syncope on exertion is a definitive sign of cardiac decompensation; cardiac output is not meeting cellular oxygen needs. Systolic murmur may occur in a healthy pregnant woman because of the displacement of the heart, caused by the enlarging uterus that shifts the contents of the thoracic cavity and the increased blood volume and cardiac output. Heart palpitations and a displaced apical pulse both may occur in a healthy pregnant woman because of displacement of the heart caused by enlargement of the uterus that shifts the contents of the thoracic cavity, and the increased blood volume and cardiac output.
A client is receiving continuous ECG monitoring while intravenous medication is being administered for premature ventricular complexes (PVC). Which dysrhythmia does the nurse conclude that the client is experiencing when the following rhythm appears on the ECG monitor?
Ventricular Tachycardia Rationale: Ventricular tachycardia has a rate of 140 to 200 or even 250 beats per min; the rhythm is usually regular but may vary. P waves are unidentifiable. PR intervals are unmeasurable. QRS complexes are wide and bizarre. Atrial flutter is characterized by an atrial rate of 200 to 350 beats per min and a ventricular rate of approximately 150 beats per min; flutter to ventricular responses usually are 2:1, 3:1, or 4:1. Atrial fibrillation is characterized by an atrial rate of 350 to 600 beats per min and a variable ventricular rate; the rhythm is grossly irregular. Ventricular fibrillation reflects a rapid, feeble twitching/quivering of the ventricles; it has an irregular sawtooth configuration with unidentifiable PR intervals and QRS complexes.
