Chapter 7: Dysrhythmia Interpretation and Management
Interpret the following rhythm: a.Sinus rhythm with multifocal premature ventricular contractions b.Sinus rhythm with unifocal premature ventricular contractions c.Sinus rhythm with trigeminal premature ventricular contractions d.Sinus rhythm with paired premature ventricular contractions (couplets)
ANS: B A single ectopic focus produces PVC waveforms that look alike, called unifocal PVCs. Waveforms of PVCs arising from multiple foci are not identical and are called multifocal PVCs. PVCs may occur in a predictable pattern, such as every other beat (bigeminal), every third beat (trigeminal), or every fourth beat (quadrigeminal). PVCs also can occur sequentially. Two PVCs in a row are called a pair, and three or more in a row are called nonsustained ventricular tachycardia.
The normal width of the QRS complex is which of the following? (Select all that apply.) a. 0.06 to 0.10 seconds. b. 0.12 to 0.20 seconds. c. 1.5 to 2.5 small boxes. d. 3.0 to 5.0 small boxes. e. 0.04 seconds or greater.
a. 0.06 to 0.10 seconds. c. 1.5 to 2.5 small boxes.
The patient is in chronic junctional escape rhythm with no atrial activity noted. Studies have demonstrated normal AV node function. This patient may be a candidate for which type of pacing? a. Atrial pacing b. Ventricular pacing c. Dual-chamber pacing d. Transcutaneous pacing
a. Atrial pacing
Sinus bradycardia is a symptom of which of the following? (Select all that apply.) a. Calcium channel blocker medication b. Beta-blocker medication c. Athletic conditioning d. Hypothermia e. Hyperthyroidism
a. Calcium channel blocker medication b. Beta-blocker medication c. Athletic conditioning d. Hypothermia
Which of the following are common causes of sinus tachycardia? (Select all that apply.) a. Hyperthyroidism b. Hypovolemia c. Hypothyroidism d. Heart Failure e. Sleep
a. Hyperthyroidism b. Hypovolemia d. Heart Failure
Because of the location of the AV node, the possible P waveforms that are associated with junctional rhythms include which of the following? (Select all that apply.) a. No P wave b. Inverted P wave c. Shortened PR interval d. P wave after the QRS complex e. Normal P wave and PR interval
a. No P wave b. Inverted P wave c. Shortened PR interval d. P wave after the QRS complex
The nurse is caring for a patient who has atrial fibrillation. Sequelae that place the patient at greater risk for mortality/morbidity include which of the following? (Select all that apply.) a. Stroke b. Ashman beats c. Pulmonary emboli d. Prolonged PR interval e. Decreased cardiac output
a. Stroke c. Pulmonary emboli e. Decreased cardiac output
Which of the following is true about a patient diagnosed with sinus arrhythmia? a. The heart rate varies, dependent on vagal tone and respiratory pattern. b. Immediate treatment is essential to prevent death. c. Sinus arrhythmia is not well tolerated by most patients. d. PR and QRS interval measurements are prolonged.
a. The heart rate varies, dependent on vagal tone and respiratory pattern.
The nurse is reading the cardiac monitor and notes that the patient's heart rhythm is extremely irregular and there are no discernible P waves. The ventricular rate is 90 beats per minute, and the patient is hemodynamically stable. The nurse realizes that the patient's rhythm is: a. atrial fibrillation. b. atrial flutter. c. atrial flutter with rapid ventricular response. d. junctional escape rhythm.
a. atrial fibrillation.
The patient has an irregular heart rhythm. To determine an accurate heart rate, the nurse first: a. identifies the markers on the ECG paper that indicate a 6-second strip. b. counts the number of large boxes between two consecutive P waves. c. counts the number of small boxes between two consecutive QRS complexes. d. divides the number of complexes in a 6-second strip by 10.
a. identifies the markers on the ECG paper that indicate a 6-second strip.
The patient's heart rhythm shows an inverted P wave with a PR interval of 0.06 seconds. The heart rate is 54 beats per minute. The nurse recognizes the rhythm as a junctional escape rhythm, and understands that the rhythm is due to the: a. loss of sinus node activity. b. increased rate of the AV node. c. increased rate of the SA node. d. decreased rate of the AV node.
a. loss of sinus node activity.
The nurse is caring for a patient who is on a cardiac monitor. The nurse realizes that the sinus node is the pacemaker of the heart because it is: a. the fastest pacemaker cell in the heart. b. the only pacemaker cell in the heart. c. the only cell that does not affect the cardiac cycle. d. located in the left side of the heart.
a. the fastest pacemaker cell in the heart.
The patient is having premature ventricular contractions (PVCs). The nurse's greatest concern should be: a. the proximity of the R wave of the PVC to the T wave of a normal beat. b. the fact that PVCs are occurring, because they are so rare. c. if the number of PVCs are decreasing. d. if the PVCs are wider than 0.12 seconds.
a. the proximity of the R wave of the PVC to the T wave of a normal beat.
The patient is in third-degree heart block (complete heart block) and is symptomatic. The treatment for this patient is which of the following? (Select all that apply.) a. transcutaneous pacemaker. b. atropine IV. c. temporary transvenous pacemaker. d. permanent pacemaker. e. amiodarone IV.
a. transcutaneous pacemaker. c. temporary transvenous pacemaker. d. permanent pacemaker.
Electrocardiogram (ECG) paper contains a standardized grid where the horizontal axis measures time and the vertical axis measures voltage or amplitude. The nurse must understand that each horizontal box indicates: a. 200 milliseconds or 0.20 seconds duration. b. 40 milliseconds or 0.04 seconds duration. c. 3 seconds duration. d. millivolts of amplitude.
b. 40 milliseconds or 0.04 seconds duration.
The normal rate for the SA node when the patient is at rest is: a. 40 to 60 beats per minute. b. 60 to 100 beats per minute. c. 20 to 40 beats per minute. d. more than100 beats per minute.
b. 60 to 100 beats per minute.
The nurse is calculating the rate for a regular rhythm. There are 20 small boxes between each P wave and 20 small boxes between each R wave. What is the ventricular rate? a. 50 beats/min b. 75 beats/min c. 85 beats/min d. 100 beats/min
b. 75 beats/min
The patient's heart rate is 70 beats per minute, but the P waves come after the QRS complex. The nurse correctly determines that the patient's heart rhythm is: a. a normal junctional rhythm. b. an accelerated junctional rhythm. c. a junctional tachycardia. d. atrial fibrillation.
b. an accelerated junctional rhythm.
The nurse notices ventricular tachycardia on the heart monitor. When the patient is assessed, the patient is found to be unresponsive with no pulse. The nurse should: a. treat with intravenous amiodarone or lidocaine. b. begin cardiopulmonary resuscitation and advanced life support. c. provide electrical cardioversion. d. ignore the rhythm since it is benign.
b. begin cardiopulmonary resuscitation and advanced life support.
The rhythm on the cardiac monitor is showing numerous pacemaker spikes, but no P waves or QRS complexes following the spikes. The nurse realizes this as: a. normal pacemaker function. b. failure to capture. c. failure to pace. d. failure to sense.
b. failure to capture.
The nurse is examining the patient's cardiac rhythm strip in lead II and notices that all of the P waves are upright and look the same except one that has a different shape and is inverted. The nurse realizes that the P wave with the abnormal shape is probably: a. from the SA node since all P waves come from the SA node. b. from some area in the atria other than the SA node. c. indicative of ventricular depolarization. d. normal even though it is inverted in lead II.
b. from some area in the atria other than the SA node.
One of the functions of the atrioventricular (AV) node is to: a. pace the heart if the ventricles fail. b. slow the impulse arriving from the SA node. c. send the impulse to the SA node. d. allow for ventricular filling during systole.
b. slow the impulse arriving from the SA node.
The patient is scheduled to have a permanent pacemaker implanted. The patient asks the nurse, "How long will the battery in this thing last?" The nurse should answer, a. "Life expectancy is about 1 year. Then it will need to be replaced." b. "Pacemaker batteries can last up to 25 years with constant use." c. "Battery life varies depending on usage, but it can last up to 10 years." d. "Pacemakers are used to treat temporary problems so the batteries don't last long."
c. "Battery life varies depending on usage, but it can last up to 10 years."
The patient is asymptomatic but is diagnosed with second-degree heart block Mobitz I. The patient is on digitalis medication at home. The nurse should expect that: a. the patient has had an anterior wall myocardial infarction. b. the physician will order the digitalis to be continued in the hospital. c. a digitalis level would be ordered upon admission. d. the patient will require a transcutaneous pacemaker.
c. a digitalis level would be ordered upon admission.
The patient is admitted with sinus pauses causing periods of loss of consciousness. The patient is asymptomatic, awake and alert, but fatigued. He answers questions appropriately. When admitting this patient, the nurse should first: a. prepare the patient for temporary pacemaker insertion. b. prepare the patient for permanent pacemaker insertion. c. assess the patient's medication profile. d. apply transcutaneous pacemaker paddles.
c. assess the patient's medication profile.
The patient has a permanent pacemaker in place with a demand rate set at 60 beats/min. The cardiac monitor is showing a heart rate of 44 beats/min with no pacemaker spikes. The nurse realizes this as: a. normal pacemaker function. b. failure to capture. c. failure to pace. d. failure to sense.
c. failure to pace.
The QT interval is the total time taken for ventricular depolarization and repolarization. Prolongation of the QT interval: a. decreases the risk of lethal dysrhythmias. b. usually occurs when heart rate increases. c. increases the risk of lethal dysrhythmias. d. can only be measured with irregular rhythms.
c. increases the risk of lethal dysrhythmias.
The nurse notices that the patient has a first-degree AV block. Everything else about the rhythm is normal. The nurse should: a. prepare to place the patient on a transcutaneous pacemaker. b. give the patient atropine to shorten the PR interval. c. monitor the rhythm and patient's condition. d. give the patient an antiarrhythmic medication.
c. monitor the rhythm and patient's condition.
The nurse understands that in a third-degree AV block: a. every P wave is conducted to the ventricles. b. some P waves are conducted to the ventricles. c. none of the P waves are conducted to the ventricles. d. the PR interval is prolonged.
c. none of the P waves are conducted to the ventricles.
When assessing the 12-lead electrocardiogram (ECG) or a rhythm strip, it is helpful to understand that the electrical activity is viewed in relation to the positive electrode of that particular lead. When an electrical signal is aimed directly at the positive electrode, the inflection will be: a. negative. b. upside down. c. upright. d. equally positive and negative.
c. upright.
The nurse is working on the night shift when she notices sinus bradycardia on the patient's cardiac monitor. The nurse should: a. give atropine to increase heart rate. b. begin transcutaneous pacing of the patient. c. start a dopamine infusion to stimulate heart function. d. assess for hemodynamic instability.
d. assess for hemodynamic instability.
The patient is admitted with a condition that requires cardiac rhythm monitoring. To apply the monitoring electrodes, the nurse must first: a. apply a moist gel to the chest. b. make certain that the electrode gel is dry. c. avoid soaps to avoid skin irritation. d. clip chest hair if needed.
d. clip chest hair if needed.
The patient's heart rate is 165 beats per minute. His cardiac monitor shows a rapid rate with narrow QRS complexes. The P waves cannot be seen, but the rhythm is regular. The patient's blood pressure has dropped from 124/62 to 78/30. His skin is cold and diaphoretic and he is complaining of nausea. The nurse prepares the patient for: a. administration of beta-blockers. b. administration of atropine. c. transcutaneous pacemaker insertion. d. emergent cardioversion.
d. emergent cardioversion.
Interpret the following rhythm: a.Sinus rhythm with multifocal premature ventricular contractions b.Sinus rhythm with unifocal premature ventricular contractions c.Sinus rhythm with bigeminal premature ventricular contractions d.Sinus rhythm with paired premature ventricular contractions (couplets)
ANS: A A single ectopic focus produces PVC waveforms that look alike, called unifocal PVCs. Waveforms of PVCs arising from multiple foci are not identical and are called multifocal PVCs. PVCs may occur in a predictable pattern, such as every other beat (bigeminal), every third beat (trigeminal), or every fourth beat (quadrigeminal). PVCs can also occur sequentially. Two PVCs in a row are called a pair (or couplets), and three or more in a row are called nonsustained ventricular tachycardia.
Interpret the following rhythm: a.Atrial fibrillation b.Atrial flutter c.Atrial flutter with RVR d.Junctional escape rhythm
ANS: A Atrial fibrillation arises from multiple ectopic foci in the atria, causing chaotic quivering of the atria and ineffectual atrial contraction. The AV node is bombarded with hundreds of atrial impulses and conducts these impulses in an unpredictable manner to the ventricles. The atrial rate may be as high 700 and no discernible P waves can be identified, resulting in a wavy baseline and an extremely irregular ventricular response. Atrial flutter arises from a single irritable focus in the atria. The atrial focus fires at an extremely rapid, regular rate, between 240 and 320 beats per minute. The P waves are called flutter waves and may have a sawtooth appearance. The ventricular response may be regular or irregular based on how many flutter waves are conducted through the AV node. Atrial flutter with RVR occurs when atrial impulses cause a ventricular response greater than 100 beats per minute. A junctional escape rhythm is a ventricular rate between 40 and 60 beats per minute with a regular rhythm. P waves may be absent, inverted, or follow the QRS complex. If a P wave is present before the QRS complex, the PR interval is shortened to less than 0.12 milliseconds. QRS complex is normal.
Interpret the following rhythm: a.Junctional rhythm b.An accelerated junctional rhythm c.A junctional tachycardia d.Atrial fibrillation
ANS: A The normal intrinsic rate for the AV node and junctional tissue is 40 to 60 beats per minute, but rates can accelerate. An accelerated junctional rhythm has a rate between 60 and 100 beats per minute, and the rate for junctional tachycardia is greater than 100 beats per minute. If a P wave precedes QRS, it is inverted or upside down; the P wave may not be visible, or it may follow the QRS. If a P wave is present before the QRS, the PR interval is shortened to less than 0.12 milliseconds. Atrial fibrillation arises from multiple ectopic foci in the atria, causing chaotic quivering of the atria and ineffectual atrial contraction. The AV node is bombarded with hundreds of atrial impulses and conducts these impulses in an unpredictable manner to the ventricles.
Interpret the following rhythm: a.R-on-T phenomenon leading to ventricular fibrillation b.Sinus rhythm with multifocal premature ventricular contractions c.Nonsustained ventricular tachycardia d.Sinus rhythm with bigeminal premature ventricular contractions
ANS: A The peak of the T wave through the downslope of the T wave is considered the vulnerable period, which coincides with partial repolarization of the ventricles. If a PVC occurs during the T wave, ventricular tachycardia may occur. When the R wave of a PVC falls on the T wave of a normal beat, it is referred to as the R-on-T phenomenon. This strip does not show sinus rhythm, multi-focal PVCs (PVCs that are from different places in the heart and therefore look different), non-sustained ventricular tachycardia, or bigeminal premature ventricular contractions (where every other beat is a PVC).
Interpret the following rhythm: a.Atrial flutter with variable conduction b.Ventricular fibrillation c.Atrial fibrillation d.Atrial flutter with RVR (rapid ventricular response)
ANS: A Atrial flutter arises from a single irritable focus in the atria. The atrial focus fires at an extremely rapid, regular rate, between 240 and 320 beats per minute. The P waves are called flutter waves and may have a sawtooth appearance. The ventricular response may be regular or irregular based on how many flutter waves are conducted through the AV node. Atrial flutter with RVR occurs when atrial impulses cause a ventricular response greater than 100 beats per minute. Atrial fibrillation arises from multiple ectopic foci in the atria, causing chaotic quivering of the atria and ineffectual atrial contraction.
Interpret the following rhythm: a.Sinus rhythm with PACs b.Normal sinus rhythm c.Sinus tachycardia d.Sinus bradycardia
ANS: A The underlying rhythm is identified first. Following this step, the dysrhythmia that is occurring to disrupt the underlying rhythm is then determined. A premature atrial contraction (PAC) is a single ectopic beat arising from atrial tissue, not the sinus node. The PAC occurs earlier than the next normal beat and interrupts the regularity of the underlying rhythm. The P wave of the PAC has a different shape than the sinus P wave because it arises from a different area in the atria; it may follow or be in the T wave of the preceding normal beat. If the early P wave is in the T wave, this T wave will look different from the T wave of a normal beat. Normal sinus rhythm (NSR) 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 0.06 to 0.10 seconds. P and QRS waves are consistent in shape. Sinus tachycardia results when the SA node fires faster than 100 beats per minute. Bradycardia is defined as a heart rate less than 60 beats per minute.
Interpret the following rhythm: a.Idioventricular rhythm b.Accelerated idioventricular rhythm c.Ventricular tachycardia d.Ventricular fibrillation
ANS: A Idioventricular rhythm is an escape rhythm that is generated by the Purkinje fibers. This rhythm emerges only when the SA and AV nodes fail to initiate an impulse. The Purkinje fibers are capable of an intrinsic rate of 20 to 40 beats per minute. Because this last pacemaker is located in the ventricles, the QRS complex appears wide and bizarre with a slow rate. No P waves are present. If the rate is between 40 and 100 beats per minute, this rhythm is called accelerated idioventricular rhythm (AIVR). Ventricular tachycardia (VT) is a rapid, life-threatening dysrhythmia originating from a single ectopic focus in the ventricles. It is characterized by at least three PVCs in a row. VT occurs at a rate greater than 100 beats per minute, but the rate is usually around 150 beats per minute and may be up to 250 beats per minute. VF produces a wavy baseline without a PQRST complex. Because a loose lead or electrical interference can produce a waveform similar to VF, it is always important to immediately assess the patient for pulse and consciousness.
Interpret the following rhythm: a. Normal sinus rhythm b. Sinus bradycardia c. Sinus tachycardia d. Sinus arrhythmia
ANS: A Normal sinus rhythm (NSR) 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 0.06 to 0.10 seconds. P and QRS waves are consistent in shape. Sinus tachycardia results when the 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.
Interpret the following rhythm: a.Atrial pacing b.Ventricular pacing c.Dual-chamber pacing d.Transcutaneous pacing
ANS: APacemakers may be used to stimulate the atrium, ventricle, or both chambers (dual-chamber pacemakers). Atrial pacing is used to mimic normal conduction and to produce atrial contraction, thus providing atrial kick. This is the case in the scenario provided. Ventricular pacing stimulates ventricular depolarization and is commonly used in emergency situations or when pacing is required infrequently. Dual-chamber pacing allows for stimulation of both atria and ventricles as needed to synchronize the chambers and mimic the normal cardiac cycle. However, with this patient, ventricular and AV function are normal. Transcutaneous pacing is delivered through the skin via external electrode pads connected to an external pacemaker.
Interpret the following rhythm: a.Normal sinus rhythm b.Sinus bradycardia c.Sinus tachycardia d.Sinus arrhythmia
ANS: B Normal sinus rhythm (NSR) 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 0.06 to 0.10 seconds. P and QRS waves are consistent in shape. Sinus tachycardia results when the 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 increases slightly during inspiration and slows slightly during exhalation because of changes in vagal tone.
Interpret the following rhythm: a.First-degree AV block b.Second-degree AV block Mobitz I (Wenckebach phenomenon) c.Second-degree AV block Mobitz II d.Third-degree AV block (complete heart block)
ANS: B Also called a Mobitz I or Wenckebach phenomenon, second-degree AV block type I is represented on the ECG as a progressive lengthening of the PR interval until there is a P wave without a QRS complex. In first-degree AV block, a P wave precedes every QRS complex, and every P wave is followed by a QRS; however, the PR interval is >0.20 seconds. Second-degree AV block type II (Mobitz II) is a more critical type of heart block that requires early recognition and intervention. There is no progressive lengthening of the PR interval, which remains the same throughout with the exception of the dropped beat(s). Third-degree block is often called complete heart block because no atrial impulses are conducted through the AV node to the ventricles. In complete heart block, the atria and ventricles beat independently of each other because the AV node is completely blocked to the sinus impulse and it is not conducted to the ventricles. One hallmark of third-degree heart block is that the P waves have no association with the QRS complexes and appear throughout the QRS waveform.
The nurse notes the following rhythm on the heart monitor. The patient is unresponsive and not breathing. The nurse should. A.treat with intravenous amiodarone or lidocaine. b.provide emergent basic and advanced life support. c.provide electrical cardioversion. d.ignore the rhythm because it is benign.
ANS: B Ventricular fibrillation (VF) is a chaotic rhythm characterized by a quivering of the ventricles, which results in total loss of cardiac output and pulse. VF is a life-threatening emergency, and the more immediate the treatment, the better the survival will be. VF produces a wavy baseline without a PQRST complex. Because a loose lead or electrical interference can produce a waveform similar to VF, it is always important to immediately assess the patient for pulse and consciousness. If no pulse is present, provide emergent basic and advanced life-support interventions, including defibrillation. IV medications can be used as part of advanced life support. Cardioversion is not warranted since the patient is pulseless. This rhythm is not benign and cannot be ignored.
Interpret the following rhythm: a.Atrial pacing b.Ventricular pacing c.Dual-chamber pacing d.Transcutaneous pacing
ANS: BPacemakers may be used to stimulate the atrium, ventricle, or both chambers (dual-chamber pacemakers). Atrial pacing is used to mimic normal conduction and to produce atrial contraction, thus providing atrial kick. Ventricular pacing stimulates ventricular depolarization and is commonly used in emergency situations or when pacing is required infrequently. This patient's pacemaker is stimulating the ventricles. Dual-chamber pacing allows for stimulation of both atria and ventricles as needed to synchronize the chambers and mimic the normal cardiac cycle. There is no evidence of a dual pacemaker since the atrial spike is not seen on the ECG strip. Transcutaneous pacing is accomplished via skin electrodes.
Interpret the following rhythm: a.Sinus rhythm with multifocal premature ventricular contractions b.Sinus rhythm with unifocal premature ventricular contractions c.Sinus rhythm with bigeminal premature ventricular contractions d.Sinus rhythm with paired premature ventricular contractions (couplets)
ANS: C A single ectopic focus produces PVC waveforms that look alike, called unifocal PVCs. Waveforms of PVCs arising from multiple foci are not identical and are called multifocal PVCs. PVCs may occur in a predictable pattern, such as every other beat (bigeminal), every third beat (trigeminal), or every fourth beat (quadrigeminal). PVCs can also occur sequentially. Two PVCs in a row are called a pair (couplet), and three or more in a row are called nonsustained ventricular tachycardia.
Interpret the following rhythm: a.Normal sinus rhythm b.Sinus bradycardia c.Sinus tachycardia d.Sinus arrhythmia
ANS: C Normal sinus rhythm (NSR) 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 0.06 to 0.10 seconds. P and QRS waves are consistent in shape. Sinus tachycardia results when the 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.
Interpret the following rhythm: a.First-degree AV block b.Second-degree AV block Mobitz I (Wenckebach phenomenon) c.Second-degree AV block Mobitz II d.Third-degree AV block (complete heart block)
ANS: C Second-degree AV block type II (Mobitz II) is a more critical type of heart block that requires early recognition and intervention. There is no progressive lengthening of the PR interval, which remains the same throughout with the exception of the dropped beat(s). Also called a Mobitz I or Wenckebach phenomenon, second-degree AV block type I is represented on the ECG as a progressive lengthening of the PR interval until there is a P wave without a QRS complex. In first-degree AV block, a P wave precedes every QRS complex, and every P wave is followed by a QRS. Third-degree block is often called complete heart block because no atrial impulses are conducted through the AV node to the ventricles. In complete heart block, the atria and ventricles beat independently of each other because the AV node is completely blocked to the sinus impulse and it is not conducted to the ventricles. One hallmark of third-degree heart block is that the P waves have no association with the QRS complexes and appear throughout the QRS waveform.
Interpret the following rhythm: a.Normal pacemaker function b.Failure to capture c.Failure to pace d.Failure to sense
ANS: CFailure to pace or fire occurs when the pacemaker fails to initiate an electrical stimulus when it should fire. The problem is noted by absence of pacer spikes on the rhythm strip. Note that after the 3-second mark, the pacemaker failed to fire. When the pacemaker generates an electrical impulse (pacer spike) and no depolarization is noted, it is described as a failure to capture. On the ECG, a pacer spike is noted, but it is not followed by a P wave (atrial pacemaker) or a QRS complex (ventricular pacemaker) within the appropriate time frame. When the pacemaker does not sense the patient's own cardiac rhythm and initiates an electrical impulse, it is called failure to sense. Failure to sense manifests as pacer spikes that fall too closely to the patient's own rhythm, earlier than the programmed rate. This is not normal pacemaker function.
Interpret the following rhythm: a.Atrial pacing b.Ventricular pacing c.Dual-chamber pacing d.Transcutaneous pacing
ANS: CPacemakers may be used to stimulate the atrium, ventricle, or both chambers (dual-chamber pacemakers). Atrial pacing is used to mimic normal conduction and to produce atrial contraction, thus providing atrial kick. Ventricular pacing stimulates ventricular depolarization and is commonly used in emergency situations or when pacing is required infrequently. Dual-chamber pacing allows for stimulation of both atria and ventricles as needed to synchronize the chambers and mimic the normal cardiac cycle. This is the case in the scenario provided as seen by pacemaker spikes in both the atrial and ventricular position.
Interpret the following rhythm: a.Sinus rhythm with multifocal premature ventricular contractions b.Sinus rhythm with unifocal premature ventricular contractions c.Sinus rhythm with bigeminal premature ventricular contractions d.Sinus rhythm with paired premature ventricular contractions (couplets)
ANS: D A single ectopic focus produces PVC waveforms that look alike, called unifocal PVCs. Waveforms of PVCs arising from multiple foci are not identical and are called multifocal PVCs. PVCs may occur in a predictable pattern, such as every other beat (bigeminal), every third beat (trigeminal), or every fourth beat (quadrigeminal). PVCs can also occur sequentially. Two PVCs in a row are called a pair (couplet), and three or more in a row are called nonsustained ventricular tachycardia
Interpret the following rhythm: a.Normal sinus rhythm b.Sinus rhythm with second-degree AV block c.Complete heart block d.Sinus rhythm with first-degree AV block
ANS: D In first-degree block, P and QRS waves are consistent in shape. P waves are small and rounded. A P wave precedes every QRS complex, which is followed by a T wave. PR interval is prolonged and is greater than 0.20 seconds. QRS complex and QT/QTc measurements are normal. Normal sinus rhythm (NSR) 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. In a complete heart block, the atria and ventricles beat independently of each other. A first-degree AV block means the PR interval is greater than 0.20 seconds
The patient is alert and talking when the nurse notices the following rhythm. The patient's blood pressure is 90/44 mm Hg. The nurse should? a.defibrillate immediately. b.begin basic life support. c.begin advanced life support. d.treat with intravenous amiodarone or lidocaine.
ANS: D Ventricular tachycardia (VT) is a rapid, life-threatening dysrhythmia originating from a single ectopic focus in the ventricles. It is characterized by at least three PVCs in a row. VT occurs at a rate greater than 100 beats per minute, but the rate is usually around 150 beats per minute and may be up to 250 beats per minute. Depolarization of the ventricles is abnormal and produces a widened QRS complex. The patient may or may not have a pulse. Determine whether the patient has a pulse. If no pulse is present, provide emergent basic and advanced life-support interventions, including defibrillation. If a pulse is present and the blood pressure is stable, the patient can be treated with intravenous amiodarone or lidocaine.
Interpret the following rhythm: a.First-degree AV block b.Second-degree AV block Mobitz I (Wenckebach phenomenon) c.Second-degree AV block Mobitz II d.Third-degree AV block (complete heart block)
ANS: D Third-degree block is often called complete heart block because no atrial impulses are conducted through the AV node to the ventricles. In complete heart block, the atria and ventricles beat independently of each other because the AV node is completely blocked to the sinus impulse and it is not conducted to the ventricles. One hallmark of third-degree heart block is that the P waves have no association with the QRS complexes and appear throughout the QRS waveform. Second-degree AV block type II (Mobitz II) is a more critical type of heart block that requires early recognition and intervention. There is no progressive lengthening of the PR interval, which remains the same throughout with the exception of the dropped beat(s). Also called a Mobitz I or Wenckebach phenomenon, second-degree AV block type I is represented on the ECG as a progressive lengthening of the PR interval until there is a P wave without a QRS complex. In first-degree AV block, a P wave precedes every QRS complex, and every P wave is followed by a QRS.
Interpret the following rhythm: a.Normal pacemaker function b.Failure to capture c.Failure to pace d.Failure to sense
ANS: DWhen the pacemaker does not sense the patient's own cardiac rhythm and initiates an inappropriate electrical impulse, it is called failure to sense. Failure to sense manifests as pacer spikes that fall too closely to the patient's own rhythm, earlier than the programmed rate. This is not normal pacemaker function. When the pacemaker generates an electrical impulse (pacer spike) and no depolarization is noted, it is described as a failure to capture. On the ECG, a pacer spike is noted, but it is not followed by a P wave (atrial pacemaker) or a QRS complex (ventricular pacemaker). Failure to pace or fire occurs when the pacemaker fails to initiate an electrical stimulus when it should fire. The problem is noted by absence of pacer spikes on the rhythm strip. When the pacemaker does not sense the patient's own cardiac rhythm and initiates an electrical impulse, it is called failure to sense.
The patient has a permanent pacemaker inserted. The provider has set the pacemaker to the demand mode at a rate of 60 beats per minute. The nurse realizes that: a. the pacemaker will pace only if the patient's intrinsic heart rate is less than 60 beats per minute. b. the demand mode often competes with the patient's own rhythm. c. the demand mode places the patient at risk for the R-on-T phenomenon. d. the fixed rate mode is safer and is the mode of choice.
a. the pacemaker will pace only if the patient's intrinsic heart rate is less than 60 beats per minute.
The patient is admitted with a fever and rapid heart rate. The patient's temperature is 103° F (39.4° C).The nurse places the patient on a cardiac monitor and finds the patient's atrial and ventricular rates are above 105 beats per minute. P waves are clearly seen and appear normal in configuration. QRS complexes are normal in appearance and 0.08 seconds wide. The rhythm is regular, and blood pressure is normal. The nurse should focus on providing: a. medications to lower heart rate. b. treatment to lower temperature. c. treatment to lower cardiac output. d. treatment to reduce heart rate.
b. treatment to lower temperature.
The nurse is talking with the patient when the monitor alarms and shows a wavy baseline without a PQRST complex. The nurse should: a. defibrillate the patient immediately. b. initiate basic life support. c. initiate advanced life support. d. assess the patient and the electrical leads.
d. assess the patient and the electrical leads.
