Ch.28: Disorders of Cardiac Conduction and Rhythm

The nurse is interpreting an electrocardiogram of a 65-year-old woman. Which should the nurse recognize as representing ventricular depolarization?

QRS complex

Which antiarrhythmic medication works by blunting the effect of sympathetic nervous system stimulation on the heart?

Beta-blockers, such as metoprolol

ECG monitoring has been found to be more sensitive than a client's report of symptoms when identifying transient ongoing myocardial ischemia. Why is this?

Most ECG-detected ischemic events are clinically silent.

A client experiencing a sinus arrest would demonstrate which symptom or finding?

Prolonged periods of asystole demonstrated on an electrocardiogram

Which degree of "heart block" results in decreased cardiac output and fainting?

Third-degree

A nurse is caring for a client with an average heart rate of 56 beats/min. The client has no adverse symptoms associated with this heart rate and is receiving no treatment. Which activity modification should the nurse suggest to avoid further slowing of the heart rate?

"Avoid bearing down while having a bowel movement."

When explaining a new diagnosis of complete heart block to a client and family, the nurse should include which statement?

"One consequence of this type of block is a very slow heart rate that limits circulation to the brain."

A client arrives at the emergency room with dizziness and a near syncopal episode. Vital signs include a heart rate of 46 and blood pressure of 86/50. The cardiac monitors show regular rhythm as above. The client states his physician has been running blood work to rule out hypothyroidism. Based on the rhythm, what does the nurse report the client has?

A symptomatic bradyarrhythmia

A client has been diagnosed with atrial flutter. Which assessment finding correlates with this diagnosis?

An atrial heart rate above 240 beats/min

A nurse is caring for four clients. Which client is most at risk for atrial fibrillation (AF)?

An older adult man who is 2 days postcoronary artery bypass surgery

A nurse is caring for a client with persistent atrial fibrillation. Which intervention is the priority?

Assessing for shortness of breath or changes in level of consciousness

Which classification of antiarrhythmic drugs acts by inhibiting the potassium current and repolarization, thereby extending the action potential and refractoriness?

Class III

A client has been admitted after being resuscitated from a cardiac arrest. The client is prescribed Class I for electrocardiogram monitoring. What type of monitoring will the nurse perform for this client?

Continuous cardiac monitoring

The nurse is assessing the electrical activity of the heart recorded on the electrocardiogram (ECG). What does the P wave represent?

Depolarization of the sinoatrial node

The nurse is assisting a client who had a myocardial infarction 2 days ago during a bath. The client suddenly lost consciousness and the nurse was unable to feel a pulse. Cardiopulmonary resuscitation was begun and the client was connected to the monitor with a gross disorganization without identifiable waveforms or intervals observed. What is a priority intervention at this time?

Immediate defibrillation

Nursing students who are studying for their upcoming cardiac exam are discussing how the heart could possibly continue to beat once removed from the body. One of the students explains that this phenomenon is directly related to automaticity. What is automaticity?

Inherent spontaneous action-potential

Respiratory sinus dysrhythmia is considered a more optimal rhythm than a rhythm where all RR intervals are equal. In respiratory sinus dysrhythmia, what is the variation in cardiac cycles related to?

Intrathoracic pressure changes that occur with respiration

Which statement describes the greatest diagnostic limitation of an electrocardiogram (ECG)?

It documents only current cardiac function.

A client is scheduled to have a Holter monitor for 48 hours to detect disturbances in conduction. Which action is important for the nurse to tell the client to ensure accuracy in correlating dysrhythmias with symptoms?

It is important to keep a diary of activities and symptoms.

Considering the PQRST complex of an electrocardiogram (ECG), which letter designation represents atrial depolarization?

P wave

The nurse assesses the electrocardiogram for depolarization of the atria. What portion of the ECG will the nurse be assessing?

P wave above the baseline

A monitored hospitalized client with a pulmonary embolism has been in atrial fibrillation (AF) for 4 days. The nurse observes the rhythm spontaneously convert to a normal sinus rhythm. Which form of AF is this?

Paroxysmal

What is the correct sequence for the generation of electrical impulses in the heart causing ventricular contraction?

SA node - AV node - bundle of His - bundle branches - Purkinje fibers

A nurse is explaining the conduction system of the heart to a client who is experiencing an dysrhythmia. Which would be the most accurate explanation?

Sinoatrial node (SA), internodal pathways, atrioventricular (AV) node, AV bundle, Purkinje fibers

A client is seen in the emergency department complaining of chest discomfort, productive cough, and a fever of over 101°F (38.3°C) for 3 days. The nurse performs an electrocardiogram and observes a rate of 110 beats per minute (bpm) with a normal P wave and a PR interval of 0.12 second preceding each QRS complex. What does the nurse determine the rhythm to be?

Sinus tachycardia

A client with supraventricular tachycardia has received a dose of verapamil to slow the heart rate. Which explanation describes the effect of this drug on the heart?

Slows the sinoatrial (SA) node pacemaker and inhibits conduction in the atrioventricular (AV) node

A 20-year-old college student, with no past medical history, arrives at the emergency room complaining of severe palpitations and dizziness that started this morning following a night of studying. The student is very upset that this is happening because the final exams are the following day. The cardiac monitor shows a heart rate of 110, regular rhythm with occasional premature ventricular complexes. The nurse explains to the student that this can happen in healthy hearts and is usually caused by stimulation of:

Sympathetic nervous system

Which dysrhythmia is considered to be the most fatal and requires immediate treatment?

Ventricular fibrillation

A client presents with uncharacteristic chest pain, and his ECG reveals T-wave elevation. This finding suggests an abnormality with which aspect of the cardiac cycle?

Ventricular repolarization

A client with a history of angina presents with uncharacteristic chest pain. The subsequent electrocardiogram (ECG) reveals T-wave elevation. This finding suggests an abnormality with which aspects of the cardiac cycle?

Ventricular repolarization

A nursing student is studying the properties of cardiac rhythm to better understand what causes dysrhythmias to occur. The student begins to understand that there is a programmed ability for certain cells to conduct impulses. Interruption in this ability can result in abnormalities of cardiac rate and rhythm; this property would be:

conductivity

An 80-year-old male client arrives for his yearly physical without any complaints, and following the checkup the physician explains that he has noted atrial fibrillation (AF) on the client's ECG. Before the physician can explain the disorder, the client becomes very upset and states he thinks he is going to die. The physician explains that atrial fibrillation involves the top chambers of the heart and that:

many people live with atrial fibrillation without even knowing they have it.

An intensive care unit nurse is caring for a client who suffered a myocardial infarction involving the anterior wall, and notes a change in the cardiac rhythm. The rhythm has a PR interval that does not change, but there are twice as many P waves as there are R waves. The nurse prepares for a temporary pacemaker insertion because the client has developed:

second-degree, type 2 AV block.

A college student is in pre-op area prior to knee surgery. The nurse attaches the cardiac monitor and notes a gradual lengthening and shortening between the R waves. The nurse realizes that this rhythm is most often found in people with healthy hearts. This rhythm is a respiratory:

sinus dysrhythmia.

A 28-year-old marathon runner comes to the clinic to obtain a physical exam for a new job. The nurse assesses a regular pulse rate of 52 beats per minute (bpm). Which common dysrhythmia is the nurse aware this client most likely has related to maintaining a large stroke volume?

Sinus bradycardia

Which client will the nurse prioritize to assess first?

The client with sinus arrest

Which type of pacing involves the placement of large patch electrodes on the anterior and posterior chest wall that can be connected by a cable to an external pulse generator?

Transcutaneous

A nurse is observing a client's cardiac status by telemetry monitoring. On the monitor, the P wave changes shape and an impulse frequently occurs before the next expected sinoatrial (SA) node impulse. The nurse interprets this rhythm by stating:

"The client is experiencing premature atrial contractions (PACs)."

A client arrives at the doctor's office reporting severe indigestion that has been intermittent; however, the pain is now constant and feels like a vise. The nurse does an ECG and recognizes that the situation is possibly emergent due to ST-segment elevation, which could indicate:

Myocardial infarction

Torsade de pointes is a specific type of polymorphic ventricular tachycardia in which the polarity of the QRS complex swings between positive and negative, often on a beat-to-beat basis. It is the result of the long QT syndrome and can cause sudden cardiac death. Which medication is not linked to torsade de pointes as a causative agent?

Tetracycline

Sick sinus syndrome is suspected in the case of a child who is postoperative following cardiac surgery. Which nursing action is most appropriate?

Monitor the child's ECG for bradycardia.

A client with a 2-week history of hyperthyroidism due to a virus is admitted for nonemergent cardioversion. The client states that she has been experiencing intermittent episodes of palpitations over the past week along with shortness of breath and fatigue. The nurse attaches the client to a cardiac monitor and notes that the client is in normal sinus rhythm with frequent episodes of atrial fibrillation. The nurse anticipates which of the following to be ordered prior to the cardioversion to avoid a possible stroke?

Transesophageal echocardiography

Which cardiac drug classification decreases sympathetic outflow to the heart and is the is the cornerstone of therapy for catecholaminergic polymorphic ventricular tachycardia (CPVT)?

Beta-adrenergic blockers