Disrhythmias
Which is a disadvantage of a centralized monitoring system? 1 It cannot diagnose dysrhythmias. 2 It measures the patients' heart rate remotely. 3 It cannot rapidly detect myocardial ischemia. Correct4 It requires continuous observation of patients' electrocardiograms (ECGs).
A centralized monitoring system is a type of telemetry monitoring system. It requires continuous observation of a group of patients' electrocardiograms at a central location. Centralized monitoring systems observe heart rate and rhythm remotely, at a site distant from the patient. A centralized monitoring system helps to detect dysrhythmias, ischemia, or infarction in patients.
A patient is experiencing third-degree AV block. Which electrocardiogram (ECG) findings are characteristic of this rhythm? Select all that apply. Correct1 The PR interval is variable. Correct2 The P wave has a normal shape. 3 The ventricular rate is irregular. 4 The atrial rate is more than 100 beats/min. Correct5 The atrial and ventricular rhythms are regular but unrelated
A third-degree AV block is often called a complete heart block because no atrial impulses are conducted through the AV node to the ventricles. In such situations, the atria and ventricles beat independently because the AV node is completely blocked to the sinus impulse and, therefore, it is not conducted to the ventricles. One of the characteristics of a third-degree heart block is that the P waves have no association with the QRS complexes and appear throughout the QRS waveform. The P wave has a normal shape. The atrial and ventricular rhythms are regular, but these are not related to each other. The atrial rate is usually a sinus rate of 60 to 100 beats/min.STUDY TIP: Avoid planning other activities that will add stress to your life between now and the time you take the licensure examination. Enough will happen spontaneously; do not plan to add to it.
The nurse is reviewing the electrocardiograms of four patients. Which conclusion would the nurse make about these electrocardiograms? 1 Patient A has atrial flutter. 2 Patient C has sinus bradycardia. 3 Patient D has sinus tachycardia. Correct4 Patient B has accelerated junctional rhythm
An accelerated junctional rhythm has a rate in the range of 61 to 100 beats/min and abnormal and inverted P waves. This describes Patient B. The atrial rate of 400 beats/min indicates atrial fibrillation, not atrial flutter. The heart rate of 150 beats/min, normal P wave, and normal PR interval indicate sinus tachycardia, not sinus bradycardia. The heart rate of 50 beats/min, normal P wave, and normal PR interval indicate sinus bradycardia, not sinus tachycardia.
A patient has an atrial rate of 450 beats per minute and a ventricular rate of 150 beats per minute. Which condition is the patient likely experiencing? Incorrect1 Atrial flutter Correct2 Atrial fibrillation 3 Ventricular fibrillation 4 Premature ventricular contractions
Atrial fibrillation is characterized by alterations in electrical conductivity of the atrium. The atrial rate is as high as 350 beats per minute to 600 beats per minute. Atrial fibrillation with controlled ventricular response is observed at a ventricular rate of 60 beats per minute to 100 beats per minute. A ventricular rate above 100 beats per minute is considered as atrial fibrillation with uncontrolled ventricular response. The atrial rate and ventricular rate in atrial flutter occur at the ratio of 2:1. The atrial rate is observed between 200 beats per minute to 350 beats per minute and the ventricular rate occurs at 150 beats per minute. Ventricular fibrillation elicits dysrhythmia and P wave and QRS complex cannot be predicted. Premature ventricular contractions elicit dysrhythmia with deflections in the heart rate.
A patient's electrocardiogram (ECG) now shows no P waves, fine and wavy lines between the QRS complexes, QRS complexes that measure 0.08 sec, and QRS complexes that occur irregularly with a rate of 120 beats/minute. Which interpretation of the rhythm would the nurse make? Correct1 Atrial fibrillation 2 Sinus tachycardia 3 Ventricular fibrillation 4 Ventricular tachycardia
Atrial fibrillation is represented on the cardiac monitor by irregular R-R intervals and small fibrillatory (f) waves. There are no normal P waves because the atria are not contracting truly, just fibrillating. Sinus tachycardia is a sinus rate above 100 beats/minute with normal P waves. Ventricular fibrillation is seen on the ECG without a visible P wave; an unmeasurable heart rate, PR, or QRS; and an irregular and chaotic rhythm. Ventricular tachycardia is seen as three or more premature ventricular contractions (PVCs) that have distorted QRS complexes with a regular or irregular rhythm; the P wave is usually buried in the QRS complex without a measurable PR interval.
Which property of heart cells is defined as the ability of the heart to respond mechanically to an impulse? 1 Automaticity 2 Excitability 3 Conductivity Correct4 Contractility
Contractility enables the cardiac cells to respond mechanically to an impulse. Automaticity provides the ability to initiate an impulse spontaneously and continuously. Excitability enables the cardiac cells to be electrically stimulated. Conductivity allows transmission of an impulse along a membrane in an orderly manner
A patient is diagnosed with pulseless ventricular tachycardia. In which order would the nurse perform the steps of defibrillation? Correct1.Turn the defibrillator on and select the proper energy level. Correct2.Check to see that the synchronizer switch is turned off. Correct3.Apply conductive materials to the chest. Incorrect4.Deliver the charge by depressing buttons on both paddles simultaneously. Incorrect5.Charge the defibrillator using the button on the defibrillator or the paddles. Incorrect6.Position the paddles firmly on the chest wall over the conductive material. Incorrect7.Call and look to see that everyone is "all clear.
Defibrillation is the treatment of choice for pulseless ventricular tachycardia. The nurse would first turn the defibrillator on and select the proper energy level, then check to see that the synchronizer switch is turned off. The nurse then would apply conductive materials to the chest and charge the defibrillator using the button on the defibrillator or the paddles. The nurse would then position the paddles firmly on the chest wall over the conductive material. The nurse would then check to see that everyone is "all clear." Finally, the nurse would deliver the charge by depressing buttons on both paddles simultaneously.
Which conditions are possible causes of the artifact in a patient's electrocardiogram (ECG) tracing? Select all that apply. Correct1 The patient is shivering. 2 The patient has dry skin. 3 The conductive gel is moist. Correct4 Electrical interference is present. Correct5 The leads and electrodes are not secure
Muscle activity caused by shivering of the patient, electrical interference, or loose leads and electrodes can cause distorted baseline and waveforms called an artifact on the ECG. Oily skin is wiped dry with alcohol to prepare the patient for ECG. Electrodes may have to be replaced if conductive gel has dried out.
Which factors contribute to artifact on a patient's telemetry monitor? 1 Disabled automaticity 2 Stimulation of the vagus nerve fibers 3 Electrodes placed in the incorrect lead Correct4 Excessive hair under the electrode pads
One reason that artifact is seen on the monitor is when leads and electrodes are not secure. Electrode pads may not be secure if there is excessive hair under the pads, the skin is oily, or diaphoresis is present. Disabled automaticity would cause an atrial dysrhythmia. Stimulation of the vagus nerve fibers causes a decrease in heart rate, not artifact. Electrodes placed in the incorrect place will measure electricity in a different plane of the heart and may have a different wave form than expected.
Which observation on a patient's telemetry electrocardiogram (ECG) monitor is a cause for concern? 1 Upright P wave 2 Flat ST segment 3 Upright T wave Correct4 Prolonged QT interval
Prolonged QT interval is cause for concern. QT disturbance may be caused by drugs, electrolyte imbalances, and changes in heart rate. Upright P wave, flat ST segment, and upright T wave are normal findings.
The nurse reviews a patient's electrocardiogram (ECG) tracing. Which interpretation would the nurse make? 1 Sinus tachycardia Correct2 Sinus bradycardia 3 Premature atrial contraction 4 Premature ventricular contraction
Sinus bradycardia is a heart rhythm that originates from the sinus node. With this rhythm, the P wave precedes each QRS complex, and it has a normal shape and duration, normal PR interval, and QRS complex. The patient with sinus bradycardia generally has a heart rate of less than 60 beats/minute. Patients with sinus tachycardia have a heart rate in the range of 101 to 200 beats/minute. Patients with premature atrial contraction generally have an irregular rhythm and a different-shaped P wave. Patients with premature ventricular contraction have wide and distorted QRS complexes.
A patient's electrocardiogram (ECG) shows a heart rate of 150 beats/minute and a normal P wave preceding each QRS complex. Which interpretation would the nurse make of these findings? 1 Atrial fibrillation Correct2 Sinus tachycardia 3 Ventricular fibrillation 4 Premature atrial contractions
Sinus tachycardia includes a heart rate of 101 beats to 180 beats per minute. The electrocardiographic study of sinus tachycardia shows a normal P wave preceding each QRS complex with normal time and duration. In atrial fibrillation, the P waves are chaotic and fibrillatory and the QRS complex is normal. The electrocardiographic study of ventricular fibrillation elicits the absence of P waves, and the PR interval and QRS interval cannot be measured. In premature atrial contraction, there are distorted P waves in the ECG.
In which order do electrical impulses travel through the heart? Correct1.Sinoatrial node Correct2.Internodal pathways Correct3.Atrioventricular node Correct4.Bundle of His Correct5.Purkinje fibers
The conduction system of the heart consists of specialized neuromuscular tissue. The electrical impulse of the heart begins at the sinoatrial node in the upper right atrium. This impulse travels through the intermodal fibers and spreads over the atrial musculature. This causes atrial contraction. The impulse then reaches the atrioventricular (AV) node. From the AV node, the impulse moves down through the bundle of His and ends at the Purkinje fibers. Impulses from the Purkinje fibers cause ventricular contractions.
Which electrocardiogram (ECG) characteristics would the nurse use to interpret that a patient is in normal sinus rhythm (NSR)? Select all that apply. Correct1 The R-R intervals are relatively consistent. Correct2 One P wave precedes each QRS complex. 3 Four to five complexes occur in a six-second strip. 4 The ST segment is higher than PR interval. Correct5 The T wave is upright.
The consistency of the R-R interval indicates regular rhythm. A normal P wave before each complex indicates that the impulse originated in the SA node. The T wave is upright and represents ventricular repolarization. The number of complexes in a six-second strip is multiplied by 10 to approximate the heart rate; therefore a normal heart rate (60 to 100) is six to ten complexes in a six-second strip. Four to five complexes in a six-second strip would calculate to a heart rate of 40 to 50, which is bradycardia. An elevation of the ST segment is a sign of cardiac ischemia and is not a characteristic of NSR.
After synchronized cardioversion, a patient's electrocardiogram (ECG) tracing reveals the following. Which interpretation would the nurse make? Correct1 The cardioversion was successful. 2 The cardioversion will need to be repeated. 3 The ECG tracing indicates hyperkalemia. 4 The patient is in an accelerated junctional rhythm
The patient has converted to a normal sinus rhythm (NSR). The cardioversion was successful and does not need to be repeated. Hyperkalemia is characterized by a peaked T wave. The T wave in this tracing is normal. Accelerated junctional rhythm is characterized by an absent P wave and inverted P wave before or following the QRS complex.
In which part of the cardiac cycle is an ectopic impulse the greatest risk to the patient? Incorrect1 1 2 3 3 4 Correct4 5
The patient is at greatest risk if the ectopic impulse falls on the T wave of a preceding beat. This is called the R-on-T phenomenon. This is especially dangerous because the premature ventricular contraction (PVC) is firing during the relative refractory period of ventricular repolarization. Excitability of the heart cells increases during this time, and the risk for the PVC to start ventricular tachycardia (VT) or ventricular fibrillation (VF) is great.
A patient has the following electrocardiogram (ECG) tracing. Which action would the nurse take? 1 Call a Code Blue. Correct2 Continue to monitor the patient. 3 Evaluate the patient's electrolyte laboratory results. 4 Document the rhythm as type I second-degree atrioventricular (AV) block
The patient is in a first-degree AV Block, a benign rhythm. The patient is not in a lethal rhythm, so do not call a Code Blue. It is not necessary to evaluate electrolytes. It is not a type I second-degree AV block.
Which information in a patient's admission history may be the cause of the patient's sinus bradycardia? Select all that apply. Correct1 Hypothermia 2 Hyperglycemia 3 Hyperthyroidism Correct4 Calcium channel blockers Correct5 Increased intracranial pressure
The possible causes of sinus bradycardia include hypothermia, treatment with calcium channel blockers, and increased intracranial pressure. Hypothermia may cause reduced venous return, thereby causing bradycardia. Calcium channel blockers cause bradycardia by decreasing automaticity of the SA node and delaying the AV node conduction. The drug also reduces myocardial contractility. Increased intracranial pressure may suppress the cardiac centers in the brain, thus reducing the heart rate. Hyperglycemia causes tachycardia by causing systemic dehydration and acidosis. Hyperthyroidism increases the levels of thyroid hormone and increases the metabolism, resulting in tachycardia.
Which statement made by the student nurse indicates the need for additional teaching about electrocardiograms (ECGs)? 1 Leads I, II, and III are bipolar. 2 Leads aVR, aVL, and aVF are unipolar. Correct3 Six bipolar leads (V1 through V6) measure the electrical forces in the horizontal plane. 4 A 12-lead ECG may show changes that suggest an electrolyte imbalance.
The six leads that measure the electrical forces in the horizontal plane are unipolar leads, not bipolar leads. Leads I, II, and III are bipolar in nature and indicate that they possess both positive and negative charges. Leads aVR, aVL, and aVF are unipolar. A 12-lead ECG may show changes suggesting structural changes, conduction disturbances, damage, electrolyte imbalance, or drug toxicity.
The nurse obtains the following six-second electrocardiogram (ECG) rhythm strip. Which interpretation would the nurse make of these findings? 1 Sinus arrhythmia Correct2 Third-degree atrioventricular (AV) block 3 Wenckebach phenomenon
Third-degree AV block represents a loss of communication between the atrium and ventricles from AV node dissociation. This is depicted on the rhythm strip as no relationship between the P waves (representing atrial contraction) and QRS complexes (representing ventricular contraction). The atria are beating totally on their own at 70 beats/min, whereas the ventricles are pacing themselves at 40 beats/min. Sinus arrhythmia is seen with a slower heart rate with exhalation and an increased heart rate with inhalation. In Wenckebach heart block, there is a gradual lengthening of the PR interval until an atrial impulse is nonconducted and a QRS complex is blocked or missing. PVCs are the early occurrence of wide, distorted QRS complexes.
Which electrocardiogram (ECG) findings are consistent with type II second-degree atrioventricular (AV) block? Select all that apply. Correct1 Atrial rhythm is regular. 2 Ventricular rate is regular. Correct3 PR intervals are consistent. 4 QRS complex is less than 0.12 second. Correct5 There are more P waves than QRS complexes.
Type II second-degree AV block (Mobitz II) is a more critical type of heart block that requires early recognition and intervention. There is more than one P wave for each QRS complex, usually in the ratio of 2:1, 3:1, or more. There is no progressive lengthening of the PR interval, which remains the same throughout, with the exception of the dropped beat(s). Atrial rhythm is regular, while ventricular rhythm may be irregular. QRS complex is greater than 0.12 second because of the presence of bundle branch block.
The nurse reviews the following electrocardiogram (ECG) tracing. Which condition is the likely cause of these findings? 1 Medications 2 Dehydration 3 Fluid overload Correct4 Myocardial ischemia
Typical ECG changes that are seen in myocardial ischemia include ST segment depression and/or T wave inversion. Medications, fluid overload, and dehydration do not often affect the ST segment position on the ECG tracing.
