NCLEX RN Practice Question 429-433

A client’s electrocardiogram strip shows atrial and ventricular rates of 110 beats/min. The PR interval is 0.14 second, the QRS complex measures 0.08 second, and the PP and RR intervals are regular. How should the nurse correctly interpret this rhythm?

1. Sinus dysrhythmia
2. Sinus tachycardia
3. Sinus bradycardia
4. Normal sinus rhythm

PACEMAKERS

Description:

Temporary or permanent device that provides electrical stimulation and maintains the heart rate when the client’s intrinsic pacemaker fails to provide a perfusing rhythm

Settings

A synchronous (demand) pacemaker senses the client’s rhythm and paces only if the client’s intrinsic rate falls below the set pacemaker rate for stimulating depolarization.
An asynchronous (fixed rate) pacemaker paces at a preset rate regardless of the client’s intrinsic rhythm and is used when the client is asystolic or profoundly bradycardic.
Overdrive pacing suppresses the underlying rhythm in tachydysrhythmias so that the sinus node will regain control of the heart.

Spikes

When a pacing stimulus is delivered to the heart, a spike (straight vertical line) is seen on the monitor or electrocardiogram strip.
Spikes precede the chamber being paced; a spike preceding a P wave indicates that the atrium is paced and a spike preceding the QRS indicates that the ventricle is being paced.
An atrial spike followed by a P wave indicates atrial depolarization and a ventricular spike followed by a QRS complex represents ventricular depolarization; this is referred to as capture.
If the electrode is in the atrium, the spike is before the P wave; if the electrode is in the ventricle, the spike is before the QRS complex.

Temporary pacemakers

Noninvasive transcutaneous pacing
Noninvasive transcutaneous pacing is used as a temporary emergency measure in the profoundly bradycardic or asystolic client until invasive pacing can be initiated.
Large electrode pads are placed on the client’s chest and back and connected to an external pulse generator.
Wash the skin with soap and water before applying electrodes.
It is not necessary to shave the hair or apply alcohol or tinctures to the skin.
Place the posterior electrode between the spine and left scapula behind the heart, avoiding placement over bone

A nurse is caring for a client who has just had implantation of an automatic internal cardioverterdefibrillator. The nurse immediately would assess which of the following items based on priority?

1. Anxiety level of the client and family
2. Presence of a Medic-Alert card for the client to carry
3. Knowledge of restrictions of postdischarge physical activity
4. Activation status of the device, heart rate cutoff, and number of shocks it is programmed to deliver

Implantable cardioverter-defibrillator (ICD)

Description

An ICD monitors cardiac rhythm and detects and terminates episodes of VT and VF.
The ICD senses VT or VF and delivers 25 to 30 J up to four times, if necessary.
An ICD is used in clients with episodes of spontaneous sustained VT or VF unrelated to an MI or in clients whose medication therapy has been unsuccessful in controlling life-threatening dysrhythmias.
Transvenous electrode leads are placed in the right atrium and ventricle in contact with the endocardium; leads are used for sensing, pacing, and delivery of cardioversion or defibrillation.
The generator is most commonly implanted in the left pectoral region.

Client education

Instruct the client in the basic functions of the ICD.
Knowthe rate cutoff of the ICD and the number of consecutive shocks that it will deliver.
Wear loose-fitting clothing over the ICD generator site.
Avoid contact sports to prevent trauma to the ICD generator and lead wires.
Report any fever, redness, swelling, or drainage from the insertion site.
Report symptoms of fainting, nausea, weakness, blackouts, and rapid pulse rates to the physician.
During shock discharge, the client may feel faint or short of breath
Instruct the client to sit or lie down if he or she feels a shock and to notify the physician.
Advise the client to maintain a log of the date, time, and activity preceding the shock, the symptoms preceding the shock, and postshock sensations.
Instruct the client and family in how to access emergency medical system.
Encourage the family to learn CPR.
Instruct the client to avoid electromagnetic fields directly over the ICD because they can inactivate the device.
Instruct the client to move away from the magnetic field immediately if beeping tones are heard, and to notify the physician.
Keep an ICD identification card in the wallet and obtain and wear a Medic-Alert bracelet.
Inform all health care providers that an ICD has been inserted; certain diagnostic tests, such as an MRI, and procedures using diathermy or electrocautery interfere with ICD function.
Advise the client of restrictions on activities such as driving and operating dangerous equipment.

A nurse is evaluating a client’s response to cardioversion. Which of the following observations would be of highest priority to the nurse?

1. Blood pressure
2. Status of airway
3. Oxygen flow rate
4. Level of consciousness

Cardioversion

Description

Cardioversion is synchronized countershock to convert an undesirable rhythm to a stable rhythm.
Cardioversion can be an elective procedure performed by the physician for stable tachydysrhythmias resistant to medical therapies or an emergent procedure for hemodynamically unstable ventricular or supraventricular tachydysrhythmias.
A lower amount of energy is used than with defibrillation.
The defibrillator is synchronized to the client’s R wave to avoid discharging the shock during the vulnerable period (T wave).
If the defibrillator were not synchronized, it could discharge on the T wave and cause VF.

Preprocedure interventions

Obtain an informed consent if an elective procedure.
Administer sedation as prescribed.
If an elective procedure, hold digoxin (Lanoxin) 48 hours preprocedure as prescribed to prevent postcardioversion ventricular irritability.
If an elective procedure for atrial fibrillation or atrial flutter, the client should receive anticoagulant therapy for 4 to 6 weeks preprocedure.

During the procedure

Ensure that the skin is clean and dry in the area where the electrode paddles will be placed.
Stop the oxygen during the procedure to avoid the hazard of fire.
Be sure that no one is touching the bed or the client when delivering the countershock.

Postprocedure interventions

Priority assessment includes ability of the client to maintain the airway and breathing.
Resume oxygen administration as prescribed.
Assess vital signs.
Assess level of consciousness.
Monitor cardiac rhythm.
Monitor for indications of successful response, such as conversion to sinus rhythm, strong peripheral pulses, an adequate BP, and adequate urine output.
Assess the skin on the chest for evidence of burns from the edges of the paddles.

A nurse would evaluate that defibrillation of a client was most successful if which of the following observations was made?

1. Arousable, sinus rhythm, BP 116/72 mm Hg
2. Arousable, marked bradycardia, BP 86/54 mm Hg
3. Nonarousable, supraventricular tachycardia, BP 122/60 mm Hg
4. Nonarousable, sinus rhythm, BP 88/60mmHg

Defibrillation

Defibrillation is an asynchronous countershockused to terminate pulseless ventricular tachycardia(VT) or VF.
Three rapid consecutive shocks are delivered,with the first at an energy of 200 J.
If unsuccessful, the shock is repeated at 200 to 300 J.
The third and subsequent shocks will be 360 J.

Before defibrillating a client be sure that theoxygen is shut off to avoid the hazard of fire and besure that no one is touching the bed or the client.

A client in ventricular fibrillation is about to be defibrillated. A nurse knows that to convert this rhythm effectively, the machine should be set at which of the following energy levels (in joules, J) for the first delivery?

1. 50 J
2. 100 J
3. 200 J
4. 360 J

Ventricular fibrillation

Description

Impulses from many irritable foci in the ventricles fire in a totally disorganized manner.
VF is a chaotic rapid rhythm in which the ventricles quiver and there is no cardiac output.
VF is fatal if not successfully terminated within 3 to 5 minutes.
Client lacks a pulse, BP, respirations, and heart sounds.

Interventions

Defibrillate the client immediately, up to 3 times consecutively at 200, 300, and 360 joules (J).
Initiate CPR.
Administer oxygen as prescribed.
Administer antidysrhythmic therapy as prescribed.