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CNA Cardiovascular Nursing (CCN(C)) study materials
CNA Cardiovascular Nursing (CCN(C)) study resources

CNA Cardiovascular Nursing (CCN(C)) practice questions

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Question 1Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

Which description best characterizes the third heart sound (S3) in an adult?

  1. A low-pitched early diastolic sound heard at the apex with the bell Correct answer.
  2. A late diastolic sound that becomes louder during inspiration
  3. A high-pitched ejection click heard just after the first heart sound
  4. A harsh systolic murmur that radiates into the carotid arteries

Explanation

S3 is produced by rapid ventricular filling in early diastole when the ventricle is volume overloaded or has reduced compliance. It is low-pitched, heard best at the apex with the bell of the stethoscope, and often becomes clearer with the patient in the left lateral decubitus position.

Question 2Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

Which range represents a normal cardiac index for an adult at rest?

  1. 4.5 to 6.0 L/min/m2
  2. 6.5 to 8.0 L/min/m2
  3. 2.5 to 4.0 L/min/m2 Correct answer.
  4. 1.0 to 2.0 L/min/m2

Explanation

Cardiac index is cardiac output divided by body surface area, which allows comparison between patients of different sizes. A normal value is approximately 2.5 to 4.0 L/min/m2; values below this range suggest inadequate tissue perfusion.

Question 3Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

A patient's blood pressure is 120/80 mmHg. Using the standard formula, what is the mean arterial pressure?

  1. 100 mmHg
  2. 87 mmHg
  3. 93 mmHg Correct answer.
  4. 80 mmHg

Explanation

Mean arterial pressure is estimated as diastolic pressure plus one-third of the pulse pressure. Here the pulse pressure is 40 mmHg, so MAP equals 80 plus approximately 13, which is about 93 mmHg.

Question 4Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

A patient has a central venous pressure of 16 mmHg, distended jugular veins, hepatomegaly, and bilateral ankle edema. How should the nurse interpret these findings?

  1. Elevated right ventricular filling pressure from right heart failure Correct answer.
  2. Normal preload indicating adequate volume status
  3. Isolated left ventricular failure without right-sided involvement
  4. Low preload consistent with hypovolemic shock

Explanation

Central venous pressure reflects right atrial and right ventricular end-diastolic pressure, with a normal range of about 2 to 8 mmHg. Distended neck veins, an enlarged liver, and peripheral edema are classic signs of right-sided congestion and elevated right heart filling pressures.

Question 5Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

Which laboratory result is most specific for myocardial injury?

  1. Elevated creatine kinase-MB
  2. Elevated B-type natriuretic peptide
  3. Elevated myoglobin
  4. Elevated cardiac troponin I Correct answer.

Explanation

Cardiac troponin I and T are structural proteins unique to myocardial cells, so their elevation in blood indicates myocardial injury with high specificity. They rise within a few hours of injury and remain elevated for days, which aids detection of infarction after the initial presentation.

Question 6Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

Which pressures does the pulmonary artery wedge pressure best estimate?

  1. Left atrial pressure and left ventricular end-diastolic pressure Correct answer.
  2. Right atrial pressure and tricuspid valve severity
  3. Systemic vascular resistance and left ventricular afterload
  4. Pulmonary artery systolic pressure during exercise

Explanation

When the catheter balloon is inflated, the column of blood transmits left atrial pressure back to the tip of the catheter. Because the mitral valve is open in diastole, wedge pressure serves as an indirect estimate of left ventricular end-diastolic pressure and left-sided filling.

Question 7Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

Which finding meets the standard criteria for orthostatic hypotension when a patient moves from lying to standing?

  1. A fall in systolic pressure of 22 mmHg within 3 minutes Correct answer.
  2. A fall in diastolic pressure of 4 mmHg within 10 minutes
  3. A fall in systolic pressure of 8 mmHg within 3 minutes
  4. A rise in heart rate of 5 beats per minute

Explanation

Orthostatic hypotension is defined as a decrease in systolic pressure of at least 20 mmHg or a decrease in diastolic pressure of at least 10 mmHg measured within 3 minutes of standing. The drop reflects impaired baroreflex compensation or volume depletion and should prompt evaluation for falls risk.

Question 8Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

A patient with a history of rheumatic fever has a low-pitched, rumbling diastolic murmur heard best at the apex. Which positioning and technique best confirm this finding?

  1. Supine with the head of the bed raised 45 degrees
  2. Left lateral decubitus position using the bell of the stethoscope Correct answer.
  3. Sitting upright and leaning forward during held expiration
  4. Standing and bearing down during a Valsalva maneuver

Explanation

A low-pitched apical diastolic murmur suggests mitral stenosis, which is best accentuated by placing the patient in the left lateral decubitus position and using the bell lightly on the chest. This position brings the left ventricle closer to the chest wall and the bell filters out higher-frequency sounds.

Question 9Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

A patient with a large pericardial effusion has a systolic pressure that falls from 128 mmHg during expiration to 112 mmHg during inspiration. How should the nurse document this finding?

  1. Pulsus paradoxus exceeding 10 mmHg Correct answer.
  2. An absent dicrotic notch caused by peripheral vasodilation
  3. A widened pulse pressure typical of aortic regurgitation
  4. Pulsus alternans indicating severe left ventricular failure

Explanation

Pulsus paradoxus is an inspiratory fall in systolic pressure greater than 10 mmHg, reflecting impaired right ventricular filling and interventricular dependence during inspiration. It is classically associated with cardiac tamponade, where the pericardial fluid compresses the chambers and limits diastolic filling.

Question 10Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

A pulmonary artery catheter reading shows a mixed venous oxygen saturation of 48% in a patient with cool extremities and oliguria. How should the nurse interpret this value?

  1. Artifact from an overestimated pulmonary artery wedge pressure
  2. Improved tissue perfusion following fluid resuscitation
  3. Increased tissue oxygen extraction caused by low cardiac output Correct answer.
  4. Increased oxygen delivery relative to tissue demand

Explanation

Mixed venous oxygen saturation reflects the balance between oxygen delivery and consumption, with a normal range of roughly 60% to 75%. A value of 48% indicates that tissues are extracting unusually large amounts of oxygen, a pattern seen when cardiac output and delivery fall, as in cardiogenic shock.

Question 11Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

Which description best characterizes a fourth heart sound (S4) in an adult?

  1. A mid-diastolic rumble that becomes louder when the patient rolls into the left lateral position
  2. A systolic click that disappears when the patient stands and returns on squatting
  3. A low-pitched late-diastolic sound reflecting atrial ejection into a stiff ventricle Correct answer.
  4. A high-pitched snapping sound heard at the start of systole, reflecting abrupt valve opening

Explanation

An S4 is generated in late diastole, immediately before S1, when atrial contraction pushes blood into a ventricle that is stiff and poorly compliant. It is low pitched, heard best at the apex with the bell, and in adults generally indicates diastolic dysfunction, ischemia, or pressure overload rather than a normal finding.

Question 12Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

Which statement best describes left ventricular ejection fraction as measured by echocardiography?

  1. The ratio of stroke volume to left ventricular end-systolic volume
  2. The pressure difference across the aortic valve measured during systole
  3. The volume of blood ejected per minute divided by body surface area
  4. The percentage of left ventricular end-diastolic volume ejected with each systole Correct answer.

Explanation

Ejection fraction equals stroke volume divided by end-diastolic volume, expressed as a percentage, and it is the standard index of left ventricular systolic performance. A normal value is roughly 55% to 70%; a fall below about 40% indicates significantly reduced systolic function.

Question 13Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

Which finding is most consistent with a pericardial friction rub?

  1. A continuous machine-like murmur heard beneath the left clavicle throughout the cardiac cycle
  2. A scratchy superficial sound heard in both systole and diastole, unaffected by breath holding Correct answer.
  3. A low-pitched early diastolic sound heard at the apex with the patient in the left lateral position
  4. A blowing holosystolic murmur at the apex that radiates to the axilla and intensifies with handgrip

Explanation

A friction rub arises from inflamed visceral and parietal pericardial surfaces sliding on each other, producing a superficial, scratchy, often triphasic sound loudest at the left sternal border with the diaphragm. Because it is cardiac in origin, it persists during breath holding, which helps distinguish it from a pleural rub.

Question 14Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

A patient's hemodynamic record shows a cardiac output of 5 L/min, a mean arterial pressure of 90 mmHg, and a central venous pressure of 6 mmHg. Using the formula SVR = [(MAP − CVP) ÷ CO] × 80, what is the systemic vascular resistance?

  1. 1536 dyn·s·cm⁻⁵
  2. 2688 dyn·s·cm⁻⁵
  3. 1344 dyn·s·cm⁻⁵ Correct answer.
  4. 1440 dyn·s·cm⁻⁵

Explanation

Systemic vascular resistance is derived from the pressure drop across the systemic circulation divided by flow, with the factor 80 converting Wood units to dyn·s·cm⁻⁵. Subtracting CVP from MAP gives 84 mmHg, dividing by 5 L/min gives 16.8 Wood units, and multiplying by 80 yields 1344 dyn·s·cm⁻⁵, which is mildly above the usual 800 to 1200 range.

Question 15Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

Which patient is the most appropriate candidate for pharmacologic stress testing rather than exercise treadmill testing?

  1. A patient with disabling arthritis who cannot reach the target heart rate while taking a beta-blocker Correct answer.
  2. A patient with stable angina who walks 12 minutes on the treadmill without symptoms or ECG changes
  3. A patient with severe reactive airway disease and frequent bronchospasm who requires evaluation for inducible ischemia
  4. A patient whose chest pain reliably occurs at peak exercise on the treadmill and who walks 10 minutes

Explanation

Vasodilator agents such as adenosine, regadenoson, and dipyridamole, or inotropic agents such as dobutamine, are used when a patient cannot exercise adequately or when the resting ECG makes exercise interpretation unreliable. Because vasodilators can precipitate bronchospasm, they are avoided in severe reactive airway disease, and patients who exercise well should undergo exercise testing first.

Question 16Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

Which assessment takes priority in the first hours after a transfemoral cardiac catheterization?

  1. Assessing the puncture site and the distal pulse, color, and sensation of the affected leg regularly Correct answer.
  2. Auscultating the lung bases for crackles at the end of each shift and whenever the patient reports dyspnea
  3. Measuring hourly urine output and specific gravity to detect contrast-induced nephropathy
  4. Recording a 12-lead electrocardiogram every 15 minutes during the first hour after the procedure

Explanation

The femoral access site can bleed, hematoma, or thrombose with few early symptoms, so frequent checks of the puncture site along with distal pulses, color, warmth, and sensation are the highest priority. A new loss of pulse or the onset of pain, pallor, or paresthesia suggests arterial compromise and must be reported immediately.

Question 17Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

Which biomarker rises earliest after the onset of an acute myocardial infarction?

  1. Cardiac troponin I
  2. Creatine kinase-MB
  3. Myoglobin Correct answer.
  4. Lactate dehydrogenase

Explanation

Myoglobin enters the circulation within roughly 1 to 4 hours of myocardial necrosis and peaks at about 6 to 9 hours, but it lacks cardiac specificity because skeletal muscle also releases it. Troponin rises at about 3 to 6 hours and remains elevated for 7 to 14 days, while CK-MB rises at 4 to 6 hours and normalizes within 2 to 3 days.

Question 18Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

A patient has a harsh crescendo-decrescendo systolic murmur heard best at the second right intercostal space and radiating to both carotid arteries. Which valvular lesion does this suggest?

  1. Aortic regurgitation
  2. Mitral valve prolapse
  3. Aortic stenosis Correct answer.
  4. Tricuspid regurgitation

Explanation

Aortic stenosis produces a systolic crescendo-decrescendo ejection murmur at the right upper sternal border that classically radiates into the carotids, often accompanied by a delayed, low-volume carotid upstroke and a soft or absent second heart sound. The murmur intensity increases with maneuvers that raise left ventricular stroke volume, such as squatting.

Question 19Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

A 12-lead ECG shows 2 mm of ST elevation in leads II, III, and aVF, with reciprocal ST depression in leads I and aVL. Which coronary artery is most likely occluded?

  1. Right coronary artery Correct answer.
  2. Left circumflex artery
  3. Left main coronary artery
  4. Left anterior descending artery

Explanation

Leads II, III, and aVF view the inferior wall, so ST elevation in this group localizes an inferior infarct, which is most often caused by occlusion of the right coronary artery. Elevation in III that exceeds II, together with reciprocal depression in aVL, further favors a right coronary lesion, although a dominant circumflex can occasionally produce inferior changes.

Question 20Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

A patient's jugular venous tracing shows intermittent, unusually prominent 'a' waves while the ventricular rhythm is slow and regular at 40 beats/min. Which explanation best accounts for this finding?

  1. Atrial contraction against a closed tricuspid valve during atrioventricular dissociation Correct answer.
  2. Tricuspid regurgitation producing a large systolic v wave in the jugular tracing
  3. Constrictive pericarditis producing a prominent early diastolic y descent
  4. Atrial fibrillation with loss of organized atrial contraction and absent a waves

Explanation

Cannon 'a' waves occur when the right atrium contracts while the tricuspid valve is closed, so blood is forced backward into the jugular veins. With complete atrioventricular block and a slow junctional or ventricular escape rhythm, the atria and ventricles beat independently, so some atrial contractions fall during ventricular systole and produce intermittent cannon waves.

Question 21Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

Which description of chest discomfort is most typical of stable angina pectoris?

  1. Substernal pressure provoked by exertion and relieved by rest Correct answer.
  2. Tearing pain that radiates between the scapulae
  3. Sharp pain that worsens with deep inspiration and coughing
  4. Burning discomfort that occurs after meals and awakens the patient at night

Explanation

Stable angina classically produces substernal pressure, squeezing, or heaviness that is precipitated by physical exertion or emotional stress and relieved within minutes by rest or nitroglycerin. The discomfort may radiate to the jaw, shoulder, or arm but is not pleuritic or tearing. These features reflect reversible myocardial ischemia rather than pericardial, aortic, or esophageal disease.

Question 22Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

What is the primary purpose of measuring the ankle-brachial index in an adult patient?

  1. To quantify the severity of valvular aortic stenosis
  2. To detect orthostatic changes in blood pressure
  3. To screen for lower-extremity arterial disease Correct answer.
  4. To estimate left ventricular ejection fraction at the bedside

Explanation

The ankle-brachial index compares the highest systolic pressure at the ankle with the higher of the two brachial systolic pressures. A ratio of 0.90 or less suggests peripheral arterial disease, while values above 1.30 may indicate noncompressible vessels. It is a simple screening tool for lower-extremity arterial insufficiency.

Question 23Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

A patient has a decrescendo diastolic murmur heard best at the left sternal border when sitting and leaning forward. Which valve abnormality does this finding most suggest?

  1. Aortic stenosis
  2. Aortic regurgitation Correct answer.
  3. Tricuspid regurgitation
  4. Mitral stenosis

Explanation

Aortic regurgitation produces an early diastolic decrescendo murmur along the left sternal border that is accentuated when the patient sits and leans forward. The murmur reflects retrograde flow across an incompetent aortic valve and is often accompanied by a widened pulse pressure. Mitral stenosis causes a low-pitched diastolic rumble at the apex, while aortic stenosis causes a systolic crescendo-decrescendo murmur.

Question 24Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

Which ECG measurement is most important to review before administering a medication known to prolong ventricular repolarization?

  1. QTc interval Correct answer.
  2. ST segment
  3. QRS duration
  4. PR interval

Explanation

The QTc interval estimates ventricular repolarization time and is calculated by correcting the measured QT interval for heart rate. Marked QTc prolongation increases the risk of torsades de pointes, especially when drugs that further delay repolarization are given. The PR interval reflects atrioventricular conduction, the QRS duration reflects ventricular depolarization, and the ST segment reflects injury or ischemia.

Question 25Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

A patient has unilateral calf swelling and pain, and the clinician suspects a first episode of deep vein thrombosis. Which diagnostic test is most appropriate to confirm the diagnosis?

  1. Ankle-brachial index
  2. D-dimer assay alone
  3. Transthoracic echocardiography
  4. Compression duplex ultrasound Correct answer.

Explanation

Compression venous duplex ultrasonography is the first-line imaging test for confirming a suspected first episode of deep vein thrombosis. A D-dimer assay is sensitive but nonspecific, so it is most useful for excluding DVT in low-risk patients rather than confirming the diagnosis. The ankle-brachial index assesses arterial disease, and transthoracic echocardiography evaluates cardiac structures.

Question 26Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

Which maneuver most specifically increases the intensity of the murmur caused by hypertrophic obstructive cardiomyopathy?

  1. Valsalva maneuver Correct answer.
  2. Passive leg elevation
  3. Squatting
  4. Deep inspiration

Explanation

The Valsalva maneuver reduces venous return and left ventricular preload, which makes the dynamic left ventricular outflow tract obstruction of hypertrophic cardiomyopathy worse and increases the murmur. Squatting, passive leg elevation, and handgrip tend to increase preload or afterload and typically decrease the murmur. Deep inspiration mainly increases right-sided heart sounds.

Question 27Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

Which group of ECG leads best detects ischemia of the lateral wall of the left ventricle?

  1. Leads II, III, and aVF
  2. Leads V1 through V3
  3. Leads V3 and V4
  4. Leads I, aVL, V5, V6 Correct answer.

Explanation

Lateral left ventricular ischemia is detected in leads I, aVL, V5, and V6, which face the lateral wall of the left ventricle. Leads II, III, and aVF look at the inferior wall, while V1 through V4 look at the anteroseptal and anterior walls. Recognizing the lead territory helps localize ischemia and guide urgent management.

Question 28Cardiovascular assessment: history, physical examination, hemodynamic monitoring and diagnostic testing

Which finding best predicts that a mechanically ventilated patient will increase cardiac output after a fluid bolus?

  1. Mixed venous oxygen saturation of 70%
  2. Pulse pressure variation greater than 13% Correct answer.
  3. Pulmonary artery wedge pressure of 18 mmHg
  4. Central venous pressure of 12 mmHg

Explanation

Dynamic indices such as pulse pressure variation greater than 13% during mechanical ventilation suggest that the heart is operating on the steep portion of the Frank-Starling curve and is likely to respond to fluid. Static filling pressures including central venous pressure and pulmonary artery wedge pressure correlate poorly with fluid responsiveness. Mixed venous oxygen saturation reflects the balance between oxygen delivery and consumption rather than volume status.

Question 29Dysrhythmias and conduction disturbances: recognition, monitoring and nursing management

Which set of findings describes normal sinus rhythm?

  1. Rate 40 to 60 with no P waves and narrow QRS
  2. Rate 120 to 160 with sawtooth flutter waves
  3. Irregularly irregular rate with absent P waves
  4. Rate 60 to 100 with upright P before each QRS Correct answer.

Explanation

Normal sinus rhythm is generated by the sinoatrial node at 60 to 100 beats per minute. Each beat should have an upright P wave in lead II, a constant PR interval of 0.12 to 0.20 second, and a QRS after every P wave. The rhythm is regular, and the QRS is usually narrow unless conduction disease is present.

Question 30Dysrhythmias and conduction disturbances: recognition, monitoring and nursing management

A patient with atrial fibrillation has an apical rate of 128 and a radial rate of 104. What does this difference indicate?

  1. Pulse deficit from ineffective filling Correct answer.
  2. A normal finding in sinus rhythm
  3. A sign of ventricular standstill
  4. An artifact from lead placement

Explanation

In atrial fibrillation, rapid or irregular ventricular beats may not produce enough stroke volume to create a palpable radial pulse. The difference between the apical and radial rates is the pulse deficit. It reflects ineffective ventricular filling and should be documented with both rates.

Question 31Dysrhythmias and conduction disturbances: recognition, monitoring and nursing management

Which finding defines first-degree atrioventricular block?

  1. Absent P waves with a wide QRS escape rhythm
  2. More P waves than QRS complexes at a constant PR
  3. Progressive PR lengthening until one QRS is dropped
  4. PR above 0.20 second, no dropped beats Correct answer.

Explanation

First-degree AV block is present when the PR interval exceeds 0.20 second but every P wave is conducted to the ventricles. It is a delay, not a dropped beat, and the PR interval remains constant. The rhythm is usually regular and may be asymptomatic.

Question 32Dysrhythmias and conduction disturbances: recognition, monitoring and nursing management

A monitor shows grouped beating: the PR interval lengthens over several beats, then a QRS is dropped. Which rhythm is this?

  1. Mobitz I second-degree AV block Correct answer.
  2. Mobitz II second-degree AV block
  3. First-degree AV block with a fixed PR
  4. Third-degree AV block with AV dissociation

Explanation

Mobitz I, or Wenckebach, second-degree AV block shows progressive PR prolongation until a P wave is not conducted and a QRS is dropped. The dropped beat usually produces grouped beating. The PR interval after the pause is shorter again.

Question 33Dysrhythmias and conduction disturbances: recognition, monitoring and nursing management

Which finding is characteristic of third-degree atrioventricular block?

  1. Only one P wave is dropped
  2. Every P wave is followed by a QRS
  3. The PR interval shortens with each beat
  4. P waves and QRS complexes occur independently Correct answer.

Explanation

In third-degree AV block, no atrial impulses reach the ventricles, so the atria and ventricles beat independently. The PR interval varies because P waves and QRS complexes are dissociated. The ventricular rate is usually slow and may require pacing.

Question 34Dysrhythmias and conduction disturbances: recognition, monitoring and nursing management

Which intervention is recommended for unstable monomorphic ventricular tachycardia with a palpable pulse?

  1. Adenosine 6 mg rapid IV push
  2. Immediate defibrillation
  3. Transcutaneous pacing
  4. Synchronized cardioversion Correct answer.

Explanation

An unstable tachyarrhythmia with a pulse and a synchronized QRS should be treated with synchronized cardioversion. The shock is timed to the QRS to avoid delivering energy during repolarization. Defibrillation is reserved for ventricular fibrillation or pulseless ventricular tachycardia.

Question 35Dysrhythmias and conduction disturbances: recognition, monitoring and nursing management

Which action is indicated for asystole confirmed in two leads?

  1. Atropine 1 mg IV push
  2. Synchronized cardioversion
  3. Defibrillate at 200 J
  4. CPR with epinephrine Correct answer.

Explanation

Asystole is treated with high-quality CPR and epinephrine; shockable rhythms are not present. Defibrillation and synchronized cardioversion do not correct asystole and may delay compressions. Reversible causes such as hypoxia, hyperkalemia, and hypovolemia should be sought.

Question 36Dysrhythmias and conduction disturbances: recognition, monitoring and nursing management

Which finding indicates failure to capture in a patient with a pacemaker?

  1. A paced rate of 60 with one spike per QRS
  2. A pacing spike without a following QRS Correct answer.
  3. P waves that are independent of QRS
  4. A pacing spike followed by a wide QRS

Explanation

Capture means the pacing stimulus depolarizes the myocardium and produces a QRS or P wave. Failure to capture occurs when a pacing spike is not followed by a mechanical and electrical response. It can result from lead displacement, high threshold, or low output.

Question 37Dysrhythmias and conduction disturbances: recognition, monitoring and nursing management

A patient with a potassium level of 2.8 mEq/L has flattened T waves, U waves, and frequent premature ventricular contractions. Which action is the priority?

  1. Start a lidocaine infusion
  2. Replace potassium and monitor ECG Correct answer.
  3. Give calcium gluconate immediately
  4. Restrict potassium intake

Explanation

Hypokalemia causes flattened T waves, prominent U waves, and ventricular irritability, including premature ventricular contractions. The priority is careful potassium replacement with ECG monitoring because both low and rapidly corrected potassium can cause dangerous dysrhythmias. Calcium gluconate is used for hyperkalemia with ECG changes, not hypokalemia.

Question 38Dysrhythmias and conduction disturbances: recognition, monitoring and nursing management

A patient taking digoxin for atrial fibrillation has a ventricular rate of 42, nausea, and yellow-green halos. Which action is the priority?

  1. Encourage caffeine intake
  2. Give the next digoxin dose
  3. Administer atropine for bradycardia
  4. Hold digoxin and notify the provider Correct answer.

Explanation

Nausea, visual halos, and bradycardia are classic signs of digoxin toxicity. The drug should be withheld and the provider notified so the level and electrolytes, especially potassium, can be evaluated. Atropine is used only for symptomatic bradycardia and does not remove the cause.

Question 39Dysrhythmias and conduction disturbances: recognition, monitoring and nursing management

A patient's cardiac monitor shows a regular rhythm at 46 beats/min with an upright P wave before every QRS complex, a PR interval of 0.16 second, and a QRS of 0.08 second. The patient is awake, talking, and reports no chest pain or dyspnea. Which rhythm should the nurse document?

  1. Idioventricular rhythm
  2. Sinus bradycardia Correct answer.
  3. Junctional rhythm
  4. Second-degree AV block, type I

Explanation

Sinus bradycardia meets all sinus criteria: an upright P wave precedes each QRS, the PR interval is 0.12 to 0.20 second, the QRS is narrow, and the rate is below 60/min. A junctional rhythm usually has absent or inverted P waves, type I block shows progressive PR lengthening with dropped beats, and an idioventricular rhythm is wide and slow with no P waves.

Question 40Dysrhythmias and conduction disturbances: recognition, monitoring and nursing management

A monitor shows a regular ventricular rate of 75/min with sawtooth-shaped waves between QRS complexes; the atrial rate is about 300/min. Which rhythm is this?

  1. Sinus tachycardia with artifact
  2. Atrial fibrillation with a controlled rate
  3. Multifocal atrial tachycardia
  4. Atrial flutter with 4:1 conduction Correct answer.

Explanation

Flutter waves at about 300/min with a ventricular rate of 75/min indicate 4:1 atrioventricular conduction (300 divided by 4 equals 75). The sawtooth pattern comes from a reentrant circuit in the right atrium. Atrial fibrillation is irregularly irregular without discrete flutter waves, multifocal atrial tachycardia has at least three P-wave shapes, and sinus tachycardia has one P wave per QRS above 100/min.

Question 41Dysrhythmias and conduction disturbances: recognition, monitoring and nursing management

On the monitor, the nurse sees an early beat that is wide and bizarre, is not preceded by a P wave, and is followed by a pause before the next sinus beat. How should this beat be documented?

  1. Premature ventricular complex Correct answer.
  2. Artifact from patient movement
  3. Premature atrial complex
  4. Escape beat

Explanation

A wide, bizarre QRS that occurs early, lacks a preceding P wave, and is followed by a compensatory pause originates in the ventricles and is labeled a premature ventricular complex. Premature atrial complexes are narrow and preceded by an ectopic P wave. Escape beats occur late rather than early, and artifact does not produce a discrete QRS followed by a pause.

Question 42Dysrhythmias and conduction disturbances: recognition, monitoring and nursing management

A patient with a regular narrow-complex tachycardia at 186/min is alert, has a blood pressure of 118/72 mm Hg, and reports palpitations without chest pain. A vagal maneuver has failed. Which action should the nurse anticipate next?

  1. Rapid IV adenosine push with saline flush Correct answer.
  2. IV push of atropine 1 mg
  3. Immediate unsynchronized defibrillation at 200 J
  4. Synchronized cardioversion at 200 J

Explanation

Stable narrow-complex supraventricular tachycardia that persists after vagal maneuvers is treated with a rapid IV push of adenosine followed immediately by a saline flush; adenosine briefly blocks AV nodal conduction and can terminate the reentrant circuit. Unsynchronized defibrillation is reserved for ventricular fibrillation or pulseless ventricular tachycardia, atropine treats bradycardia, and synchronized cardioversion is used when the patient is unstable.

Question 43Dysrhythmias and conduction disturbances: recognition, monitoring and nursing management

The nurse finds an unresponsive patient with no pulse. The monitor shows chaotic, irregular, undulating waves of varying amplitude with no identifiable QRS complexes, and CPR is in progress. Which action should the nurse take next?

  1. Perform synchronized cardioversion at 100 J
  2. Start a dopamine infusion at 5 mcg/kg per minute
  3. Give atropine 1 mg IV push
  4. Defibrillate and immediately resume compressions Correct answer.

Explanation

The rhythm described is ventricular fibrillation, which is treated with immediate unsynchronized defibrillation followed at once by resumed chest compressions. Defibrillation is unsynchronized because there is no organized QRS for the machine to sense. Atropine has no role in ventricular fibrillation, synchronized cardioversion requires a QRS complex, and a vasopressor infusion does not replace defibrillation.

Question 44Dysrhythmias and conduction disturbances: recognition, monitoring and nursing management

A patient with a permanent pacemaker has a monitor showing pacing spikes at a fixed rate even during the patient's own QRS complexes, and one spike falls on the T wave. Which malfunction is most likely?

  1. Oversensing
  2. Failure to capture
  3. Pacemaker-mediated tachycardia
  4. Failure to sense Correct answer.

Explanation

Failure to sense, also called undersensing, means the generator does not recognize intrinsic depolarizations and continues to fire at its programmed rate, so spikes may land anywhere, including on a T wave. Failure to capture means a spike produces no QRS, oversensing is inappropriate inhibition by noncardiac signals, and pacemaker-mediated tachycardia is a rapid paced rhythm driven by retrograde conduction.

Question 45Dysrhythmias and conduction disturbances: recognition, monitoring and nursing management

A patient's monitor suddenly shows an irregular, chaotic baseline that resembles ventricular fibrillation, but the patient is alert, talking, and has a palpable radial pulse. What should the nurse do first?

  1. Administer amiodarone 150 mg IV over 10 minutes
  2. Begin chest compressions at 100 to 120/min
  3. Assess the patient and check the leads Correct answer.
  4. Defibrillate immediately

Explanation

The rhythm must always be correlated with the patient; an alert, talking patient with a palpable pulse cannot be in ventricular fibrillation, so artifact from a loose electrode, movement, or a disconnected lead is the likely cause. The nurse should assess the patient and check the lead placement and electrodes. Compressions, defibrillation, and antiarrhythmic drugs would be harmful if given for artifact alone.

Question 46Dysrhythmias and conduction disturbances: recognition, monitoring and nursing management

A patient with atrial flutter at 150/min has a blood pressure of 78/50 mm Hg, cool skin, and altered mental status. IV access is established. Which intervention is most appropriate?

  1. Synchronized cardioversion at 50 to 100 J Correct answer.
  2. Diltiazem 20 mg IV push over 2 minutes
  3. Unsynchronized defibrillation at 200 joules
  4. Adenosine 6 mg rapid IV push

Explanation

A tachyarrhythmia with a pulse and a QRS complex that causes hypotension, poor perfusion, and altered mental status is unstable and requires synchronized cardioversion, which delivers the shock outside repolarization. Atrial flutter often converts at low energy, so 50 to 100 J is an appropriate starting dose. Adenosine and diltiazem are for stable patients, and unsynchronized shocks are reserved for ventricular fibrillation or pulseless ventricular tachycardia.

Question 47Dysrhythmias and conduction disturbances: recognition, monitoring and nursing management

A patient receiving IV haloperidol develops a polymorphic ventricular rhythm with QRS complexes that twist around the isoelectric baseline, and the QT interval is 0.58 second. The patient has a pulse and a blood pressure of 96/60 mm Hg. Which action should the nurse anticipate first?

  1. Oral metoprolol
  2. IV procainamide
  3. IV magnesium sulfate Correct answer.
  4. Immediate unsynchronized defibrillation

Explanation

The rhythm is torsades de pointes, a polymorphic ventricular tachycardia associated with QT prolongation, and first-line treatment is IV magnesium sulfate along with removal of the offending drug and correction of hypokalemia or hypomagnesemia. Procainamide further prolongs the QT interval and is contraindicated. Defibrillation is reserved for pulseless collapse, and beta-blockers are not acute first-line therapy.

Question 48Dysrhythmias and conduction disturbances: recognition, monitoring and nursing management

A monitor shows a rhythm at 52/min in which every P wave is followed by a QRS except for occasional beats in which a P wave is not followed by any QRS; the PR interval is 0.18 second before every conducted beat, including the beats just before and after the dropped QRS. Which interpretation is correct?

  1. Second-degree AV block, type II Correct answer.
  2. Second-degree AV block, type I
  3. First-degree AV block
  4. Premature atrial complexes with nonconducted beats

Explanation

A constant PR interval before and after a dropped QRS, without progressive lengthening, defines type II second-degree AV block. This block reflects disease below the AV node and can progress abruptly to complete heart block, so pacing is often required. Type I block shows progressive PR lengthening before the dropped beat, first-degree block never drops beats, and a nonconducted PAC would appear as an early P wave that resets the sinus node.

Question 49Dysrhythmias and conduction disturbances: recognition, monitoring and nursing management

A telemetry strip shows an early beat with a P wave that has a different shape from the sinus P waves, followed by a narrow QRS complex and an incomplete pause. Which rhythm should the nurse document?

  1. A premature atrial contraction Correct answer.
  2. A junctional escape beat
  3. Sinus arrhythmia
  4. A premature ventricular contraction

Explanation

An ectopic atrial focus fires before the next sinus impulse, producing an early P wave with a different morphology and usually a narrow QRS complex. The pause after a PAC is typically incomplete, unlike the fully compensatory pause after a PVC.

Question 50Dysrhythmias and conduction disturbances: recognition, monitoring and nursing management

An unresponsive patient has no palpable pulse. The monitor shows organized, narrow QRS complexes at 84/min with P waves before each QRS. Which action should the nurse take first?

  1. Perform synchronized cardioversion
  2. Administer atropine 1 mg IV
  3. Deliver an unsynchronized shock
  4. Begin high-quality CPR and give epinephrine Correct answer.

Explanation

Organized electrical activity on the monitor without a palpable pulse defines pulseless electrical activity. Treatment is high-quality CPR with epinephrine while reversible causes are sought; defibrillation and cardioversion are not indicated for PEA.