Dysrhythmias

The nurse should evaluate that defibrillation of a client was most successful if which observation was made? 1. Arousable, sinus rhythm, blood pressure (BP) 116/72 mm Hg 2. Nonarousable, sinus rhythm, BP 88/60 mm Hg 3. Arousable, marked bradycardia, BP 86/54 mm Hg 4. Nonarousable, supraventricular tachycardia, BP 122/60 mm Hg

1 Rationale: After defibrillation, the client requires continuous monitoring of electrocardiographic rhythm, hemodynamic status, and neurological status. Respiratory and metabolic acidosis develop during ventricular fibrillation because of lack of respiration and cardiac output. These can cause cerebral and cardiopulmonary complications. Arousable status, adequate BP, and a sinus rhythm indicate successful response to defibrillation.

The nurse is watching the cardiac monitor, and a client's rhythm suddenly changes. There are no P waves; instead, there are fibrillatory waves before each QRS complex. How should the nurse correctly interpret the client's heart rhythm? 1. Atrial fibrillation 2. Sinus tachycardia 3. Ventricular fibrillation 4. Ventricular tachycardia

1 Rationale: Atrial fibrillation is characterized by a loss of P waves and fibrillatory waves before each QRS complex. The atria quiver, which can lead to thrombus formation. Test-Taking Strategy: .Focus on the subject, interpreting a heart rhythm. Note the data in the question. Noting the words There are no P waves should direct you to the correct option. Loss of P waves is characteristic of this dysrhythmia.

A client's electrocardiogram strip shows atrial and ventricular rates of 110beats/minute. The PR interval is 0.14 seconds, the QRS complex measures 0.08seconds, and the PP and RR intervals are regular. How should the nurse correctly interpret this rhythm? 1. Sinus tachycardia 2. Sinus bradycardia 3. Sinus dysrhythmia 4. Normal sinus rhythm

1 Rationale: Sinus tachycardia has the characteristics of normal sinus rhythm, including a regular PP interval and normal- width PR and QRS intervals; however, the rate is the differentiating factor. In sinus tachycardia, the atrial and ventricular rates are greater than 100 beats/minute.

A client has frequent bursts of ventricular tachycardia on the cardiac monitor. What should the nurse be most concerned about with this dysrhythmia? 1. It can develop into ventricular fibrillation at any time. 2. It is almost impossible to convert to a normal rhythm. 3. It is uncomfortable for the client, giving a sense of impending doom. 4. It produces a high cardiac output that quickly leads to cerebral and myocardial ischemia.

1 Rationale: Ventricular tachycardia is a life-threatening dysrhythmia that results from an irritable ectopic focus that takes over as the pacemaker for the heart. The low cardiac output that results can lead quickly to cerebral and myocardial ischemia. Clients frequently experience a feeling of impending doom. Ventricular tachycardia is treated with antidysrhythmic medications, cardioversion (if the client is awake), or defibrillation (loss of consciousness). Ventricular tachycardia can deteriorate into ventricular fibrillation at any time.

A client with atrial fibrillation is receiving a continuous heparin infusion at 1000 units/hour. The nurse determines that the client is receiving the therapeutic effect based on which results? 1. Prothrombin time of 12.5 seconds 2. Activated partial thromboplastin time of 60 seconds 3. Activated partial thromboplastin time of 28 seconds 4. Activated partial thromboplastin time longer than 120 seconds.

2 Rationale: Common laboratory ranges for activated partial thromboplastin time (aPTT) are 30 to 40 seconds. Because the aPTT should be 1.5 to 2.5 times the normal value, the cli- e n t 's a P TT w o u l d b e c o n s i d e r e d t h e r a p e u t i c i f i t w a s 6 0 s e c o n d s . Prothrombin time assesses response to warfarin therapy.

The nurse is evaluating a client's response to cardioversion. Which assessment would be the priority? 1. Blood pressure 2. Status of airway 3. Oxygen flow rate 4. Level of consciousness

2 Rationale: Nursing responsibilities after cardioversion include maintenance first of a patent airway, and then oxygen administration, assessment of vital signs and level of consciousness, and dysrhythmia detection.

A client is having frequent premature ventricular contractions. The nurse should place priority on assessment of which item? 1. Sensation of palpitations 2. Causative factors, such as caffeine 3. Blood pressure and oxygen saturation 4. Precipitating factors, such as infection

3 Rationale: Premature ventricular contractions can cause hemodynamic compromise. Therefore, the priority is to monitor the blood pressure and oxygen saturation. The shortened ventricular filling time can lead to decreased cardiac output. The client may be asymptomatic or may feel palpitations. Premature ventricular contractions can be caused by cardiac disorders; states of hypoxemia; any number of physiological stressors, such as infection, illness, surgery, or trauma; and intake of caffeine, nicotine, or alcohol.

A client is wearing a continuous cardiac monitor, which begins to sound its alarm. The nurse sees no electrocardiographic complexes on the screen. Which is the priority nursing action? 1. Call a code. 2. Call the health care provider. 3. Check the client's status and lead placement. 4. Press the recorder button on the electrocardiogram console.

3 Rationale: Sudden loss of electrocardiographic complexes indicates ventricular asystole or possibly electrode displacement. Accurate assessment of the client and equipment is necessary to determine the cause and identify the appropriate intervention. The remaining options are secondary to client assessment.

The client has developed atrial fibrillation, with a ventricular rate of 150 beats/minute. The nurse should assess the client for which associated signs and/or symptoms? 1. Flat neck veins 2. Nausea and vomiting 3. Hypotension and dizziness 4. Hypertension and headache

3 Rationale: The client with uncontrolled atrial fibrillation with a ventricular rate more than 100 beats/minute is at risk for low cardiac output because of loss of atrial kick. The nurse assesses the client for palpitations, chest pain or discomfort, hypotension, pulse deficit, fatigue, weakness, dizziness, syncope, shortness of breath, and distended neck veins.

The nurse notes that a client with sinus rhythm has a premature ventricular contraction that falls on the T wave of the preceding beat. The client's rhythm suddenly changes to one with no P waves, no definable QRS complexes, and coarse wavy lines of varying amplitude. How should the nurse correctly interpret this rhythm? 1. Asystole 2. Atrial fibrillation 3. Ventricular fibrillation 4. Ventricular tachycardia

3 Rationale: Ventricular fibrillation is characterized by irregular chaotic undulations of varying amplitudes. Ventricular fibrillation has no measurable rate and no visible P waves or QRS complexes and results from electrical chaos in the ventricles.

The nurse is watching the cardiac monitor and notices that the rhythm suddenly changes. There are no P waves, the QRS complexes are wide, and the ventricular rate is regular but more than 140 beats/minute. The nurse determines that the client is experiencing which dysrhythmia? 1. Sinus tachycardia 2. Ventricular fibrillation 3. Ventricular tachycardia 4. Premature ventricular contractions

3 Rationale: Ventricular tachycardia is characterized by the absence of P waves, wide QRS complexes (longer than 0.12 seconds), and typically a rate between 140 and 180 impulses/minute. The rhythm is regular.

The nurse is reviewing an electrocardiogram rhythm strip. The P waves and QRS complexes are regular. The PR interval is 0.16 seconds, and QRS complexes measure 0.06 seconds. The overall heart rate is 64 beats/minute. Which action should the nurse take? 1. Check vital signs. 2. Check laboratory test results. 3. Notify the health care provider. 4. Continue to monitor for any rhythm change.

4 Rationale: Normal sinus rhythm is defined as a regular rhythm, with an overall rate of 60 to 100 beats/minute. The PR and QRS measurements are normal, measuring between 0.12 and 0.20 seconds and 0.04 and 0.10 seconds, respectively. There are no irregularities in this rhythm currently, so there is no immediate need to check vital signs or laboratory results, or to notify the health care provider. Therefore, the nurse would continue to monitor the client for any rhythm change.

A client in sinus bradycardia, with a heart rate of 45 beats/minute, complains of dizziness and has a blood pressure of 82/60 mm Hg. Which prescription should the nurse anticipate will be prescribed? 1. Administer digoxin. 2. Defibrillate the client. 3. Continue to monitor the client. 4. Prepare for transcutaneous pacing.

4 Rationale: Sinus bradycardia is noted with a heart rate less than 60 beats per minute. This rhythm becomes a concern when the client becomes symptomatic. Hypotension and dizziness are signs of decreased cardiac output. Transcutaneous pacing provides a temporary measure to increase the heart rate and thus perfusion in the symptomatic client. Defibrillation is used for treatment of pulseless ventricular tachycardia and ventricular fibrillation. Digoxin will further decrease the client's heart rate. Continuing to monitor the client delays necessary intervention.

A client in ventricular fibrillation is about to be defibrillated. To convert this rhythm effectively, the monophasic defibrillator machine should be set at which energy level (in joules, J) for the first delivery? 1. 50 J 2. 120J 3. 200J 4. 360 J

4 Rationale: The energy level used for all defibrillation attempts with a monophasic defibrillator is 360 joules.

The nurse is caring for a client who has just had implantation of an automatic internal cardioverter defibrillator. The nurse should assess which item based on priority? 1. Anxiety level of the client and family 2. Presence of a MedicAlert card for the client to carry 3. Knowledge of restrictions on post discharge physical activity 4. Activation status of the device, heart rate cutoff, and number of shocks it is programmed to deliver

4 Rationale: The nurse who is caring for the client after insertion of an automatic internal cardioverter defibrillator needs to assess device settings, similar to after insertion of a permanent pacemaker. Specifically, the nurse needs to know whether the device is activated, the heart rate cutoff above which it will fire, and the number of shocks it is programmed to deliver. The remaining options are also nursing interventions but are not the priority.

A client who is receiving digoxin daily has a serum potassium level of 3 mEq/L (3 mmol/L) and is complaining of anorexia. The health care provider prescribes a serum digoxin level to be done. The nurse checks the results and should expect to note which level that is outside of the therapeutic range? 1. 0.3ng/mL 2. 0.5 ng/mL 3.0.8ng/mL 4. 1.0 ng/mL

4 Rationale: The optimal therapeutic range for digoxin is 0.5 to 0.8 ng/mL. If the client is experiencing symptoms such as anorexia and is experiencing hypokalemia as evidenced by a low potassium level, digoxin toxicity is a concern. Therefore, option 4 is correct because it is outside of the therapeutic level and an elevated level.

The nurse is assisting to defibrillate a client in ventricular fibrillation. After placing the pad on the client's chest and before discharge, which intervention is a priority? 1. Ensure that the client has been intubated. 2. Set the defibrillator to the "synchronize" mode. 3. Administer an amiodarone bolus intravenously. 4. Confirm that the rhythm is actually ventricular fibrillation.

4 Rationale: Until the defibrillator is attached and charged, the client is resuscitated by using cardiopulmonary resuscitation. Once the defibrillator has been attached, the electrocardiogram is checked to verify that the rhythm is ventricular fibrillation or pulseless ventricular tachycardia. Leads also are checked for any loose connections. A nitroglycerin patch, if present, is removed. The client does not have to be intubated to be defibrillated. The machine is not set to the synchronous mode because there is no underlying rhythm with which to synchronize. Amiodarone may be given subsequently but is not required before defibrillation.

To determine whether there is a delay in impulse conduction through the atria, the nurse will measure the duration of the patients a. P wave. b. Q wave. c. P-R interval. d. QRS complex.

ANS: A The P wave represents the depolarization of the atria. The P-R interval represents depolarization of the atria, atrioventricular (AV) node, bundle of His, bundle branches, and the Purkinje fibers. The QRS represents ventricular depolarization. The Q wave is the first negative deflection following the P wave and should be narrow and short.

The nurse notes that a patients cardiac monitor shows that every other beat is earlier than expected, has no visible P wave, and has a QRS complex that is wide and bizarre in shape. How will the nurse document the rhythm? a. Ventricular couplets b.Ventricular bigeminy c. Ventricular R-on-T phenomenond. d. Multifocal premature ventricular contractions

ANS: B Ventricular bigeminy describes a rhythm in which every other QRS complex is wide and bizarre looking. Pairs of wide QRS complexes are described as ventricular couplets. There is no indication that the premature ventricular contractions (PVCs) are multifocal or that the R-on-T phenomenon is occurring.

A patient has a junctional escape rhythm on the monitor. The nurse will expect the patient to have a heart rate of _____ beats/minute. a. 15to20 b. 20to40 c. 40to60 d. 60 to 100

ANS: C If the sinoatrial (SA) node fails to discharge, the atrioventricular (AV) node will automatically discharge at the normal rate of 40 to 60 beats/minute. The slower rates are typical of the bundle of His and the Purkinje system and may be seen with failure of both the SA and AV node to discharge. The normal SA node rate is 60 to 100 beats/minute.

A patient has a normal cardiac rhythm and a heart rate of 72 beats/minute. The nurse determines that the P-R interval is 0.24 seconds. The most appropriate intervention by the nurse would be to a. notify the health care provider immediately. b. give atropine per agency dysrhythmia protocol. c. prepare the patient for temporary pacemaker insertion. d. document the finding and continue to monitor the patient.

ANS: D First-degree atrioventricular (AV) block is asymptomatic and requires ongoing monitoring because it may progress to more serious forms of heart block. The rate is normal, so there is no indication that atropine is needed. Immediate notification of the health care provider about an asymptomatic rhythm is not necessary.

The nurse obtains a rhythm strip on a patient who has had a myocardial infarction and makes the following analysis: no visible P waves, P-R interval not measurable, ventricular rate 162, R-R interval regular, and QRS complex wide and distorted, QRS duration 0.18 second. The nurse interprets the patients cardiac rhythm as a. atrial flutter. b. sinus tachycardia. c. ventricular fibrillation. d. ventricular tachycardia.

ANS: D The absence of P waves, wide QRS, rate >150 beats/minute, and the regularity of the rhythm indicate ventricular tachycardia. Atrial flutter is usually regular, has a narrow QRS configuration, and has flutter waves present representing atrial activity. Sinus tachycardia has P waves. Ventricular fibrillation is irregular and does not have a consistent QRS duration.

The nurse needs to quickly estimate the heart rate for a patient with a regular heart rhythm. Which method will be best to use? a. Count the number of large squares in the R-R interval and divide by 300. b. Print a 1-minute electrocardiogram (ECG) strip and count the number of QRS complexes. c. Calculate the number of small squares between one QRS complex and the next and divide into 1500. d. Use the 3-second markers to count the number of QRS complexes in 6 seconds and multiply by 10.

ANS: D This is the quickest way to determine the ventricular rate for a patient with a regular rhythm. All the other methods are accurate, but take longer.

A patient who was admitted with a myocardial infarction experiences a 45-second episode of ventricular tachycardia, then converts to sinus rhythm with a heart rate of 98 beats/minute. Which of the following actions should the nurse take next? a. Immediately notify the health care provider. b. Document the rhythm and continue to monitor the patient. c. Perform synchronized cardioversion per agency dysrhythmia protocol. d. Prepare to give IV amiodarone (Cordarone) per agency dysrhythmia protocol.

ANS: DThe burst of sustained ventricular tachycardia indicates that the patient has significant ventricular irritability, and antidysrhythmic medication administration is needed to prevent further episodes. The nurse should notify the health care provider after the medication is started. Defibrillation is not indicated given that the patient is currently in a sinus rhythm. Documentation and continued monitoring are not adequate responses to this situation.