CH 28 DISORDERS OF CARDIAC CONDUCTION& RHYTHM

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 with a medical history of idiopathic cardiomyopathy is undergoing placement of an automatic implantable cardioverter defibrillator (AICD) due to episodes of non-sustained ventricular fibrillation (V-tach). When the nurse attaches the cardiac monitor, the presenting rhythm is V-tach by verifying which components on ECG? Select all that apply.

-Heart rate of 80 -Monomorphic QRS complexes -QRS complexes > 0.14 seconds

A nurse is caring for four clients. Which client is most at risk for atrial fibrillation (AF)? -A middle-aged woman with shortness of breath who takes an aspirin daily -An older adult man who is 2 days post-coronary artery bypass surgery -A male adult post-carotid endarterectomy -A female adult with diabetes mellitus and hypertension

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

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

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

Beta-blockers, such as metoprolol

The nurse is caring for a client who suffered a massive myocardial infarction and is scheduled for an immediate permanent pacemaker insertion due to severe ischemia and damage to both SA and AV nodes. The nurse would expect which of the following?

Bradycardia with rate of 20-40

A client's electrocardiogram monitor begins to sound an alarm and shows sustained ventricular fibrillation. The client is unconscious and without a pulse. Which priorityintervention should the nurse take?

Defibrillate the client

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

A 31-year-old woman with a congenital heart defect reports episodes of lightheadedness and syncope, with occasional palpitations. A resting ECG reveals sinus bradycardia, and she is suspected to have sick sinus syndrome. Which diagnostic method is the best choice to investigate the suspicion?

Holter monitoring

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

A 28-year-old client is admitted to the hospital for severe dehydration following a marathon, with fatigue the only complaint. Admission vital signs include a heart rate of 38, blood pressure 98/60, RR 16. Cardiac monitor reveals regular QRS complexes preceded by normal P waves. Which of the following does the nurse determine is the most likely cause for the bradycardia?

Large stroke volume

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

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

Prolonged periods of asystole demonstrated on an electrocardiogram

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 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

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 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.

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

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

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

Ventricular fibrillation

Paroxysmal supraventricular tachycardia arises from which form of reentry?

Arterioventricular (AV) nodal

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

An atrial heart rate above 240 beats/min

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

P wave

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 has a myocardial infarction (MI) that has damaged the right atrium, which results in interference with the SA node. The compensatory mechanism, the AV node, becomes the pacemaker of the heart and beats how many times per minute?

45 to 50 beats/minute

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

ICU nurses taking a critical care course in cardiac electrophysiology are reviewing action potential and the risk of dysrhythmias. They learn that if an electrical impulse fires just after the relative refractory period, during the supernormal excitatory period, cardiac dysrhythmias could result. Locate the supernormal excitatory period on the first complex on the rhythm strip.

After the first high peak

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

When a client has a recurrent, life-threatening arrhythmia originating either supraventricularly or ventricularly, ablation therapy is an option for treatment. What does ablation therapy do?

Isolates and destroys arrhythmogenic cardiac tissue

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 nurse notes that the PR interval on a client's electrocardiogram tracing is 0.22 seconds. Which action should the nurse take?

Monitor the client and document the findings.

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.

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

The nurse is caring for a woman who just delivered a healthy 7-pound baby 8 hours ago and is experiencing episodes of palpitations, heart rate is fluctuating between 90 and 120, blood pressure is 100/70. The client is questioning the nurse about her palpitations. What would be the most accurate response?

Palpitations are sometimes felt with fast heart rates and are often nonpathological

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

The physician decides that the best course of action for a 60-year-old client who has been diagnosed with sick sinus syndrome (SSS) is to start medications to decrease the tachyarrhythmias. Prior to starting, what does the physician explain to the client will be needed?

Permanent pacemaker

Which of the following occurs during repolarization?

Positively charged K+ moves outward across the cell membrane

The nurse is evaluating a client with cardiac problems and notes that the client's peripheral pulse is different than the apical pulse. To which physiologic response would the nurse attribute the difference in rates?

Premature beats not following normal conduction pathways

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

QRS complex

A 68-year-old male tells his health care provider that his heart rate is nearly always very low but at other times, he feels that his heart is racing, and it also seems to pause at times. This client also has occasional lightheadedness with a recent syncopal episode. What is this client's most likely diagnosis and the phenomenon underlying it?

Sick sinus syndrome as a result of a disease of his sinus node and atrial or junctional arrhythmias

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

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

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

Which client will the nurse prioritize to assess first?

The client with sinus arrest

A client is visiting the primary physician and appears extremely nervous. The intake nurse does his vital signs and notes an increase in both his heart rate and blood pressure. In an effort to better understand the client's presenting signs and symptoms the nurse asks the client about his concerns and the client states that the person who performed his pre-visit told him that he had a dysrhythmia. Which is the most therapeutic response about cardiac dysrhythmias that the nurse can make?

They can occur in diseased or healthy hearts.

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

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 client is admitted to the hospital with a diagnosis of third-degree heart block after suffering a syncopal episode in the shower that morning. The nurse explains to the client that the hot shower could cause vasodilation of the blood vessels and in combination with the heart block could cause syncope. The nurse understands that the heart block is caused by:

an interference in conduction.

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

A group of nursing students is discussing ventricular dysrhythmias and one student is unsure why a client with frequent premature ventricular complexes (PVCs) has an irregular radial pulse. One of the other students explains that premature ventricular complexes often do not produce a palpable pulse due to:

decreased ventricular filling time.

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.