Change ahead : Revised CMC test plan from AACN’s 2025 study of practice · AACN
Monitoring and diagnostics, numbers to decisions
CMC · Section IV · 14% of the revised plan
The smallest section, 14% of the revised exam, but its numbers run through the others. The revised plan merges two lists into one and adds cardiac MRI and CT, while mixed venous gases are renamed venous blood gases.
Twelve tools, regrouped by what they measure (test plan, p. 2):
Pressures and flows: invasive and noninvasive hemodynamic monitoring; remote monitoring such as implanted pulmonary artery pressure sensors and dysrhythmia monitoring.
Gases: arterial blood gases, venous blood gases (SvO2 and ScvO2; the older plan said mixed venous gases), pulse oximetry, end-tidal capnography.
Electrical: the ECG.
Imaging: echocardiography, radiography, cardiac MRI and CT (new).
Tests: laboratory testing and cardiac stress testing.
12 questions on monitoring and diagnostics
0 of 12 attempted · 0 correct · 0 missed
Monitoring and Diagnostics · 14%
During a dobutamine stress echocardiogram, which finding requires the test to be stopped early?
Answer and why, all 4 options
Occasional single PVCs are common during dobutamine infusion. Sustained or complex ventricular arrhythmias, not isolated beats, end the test.
A systolic of 180 is below the usual stopping thresholds of about 220 systolic or a large fall in pressure. Stopping here would end a valid test early.
Reaching a target heart rate around 85 percent of the age-predicted maximum is the goal of dobutamine stress. A rate of 120 is a reason to continue.
A new wall-motion abnormality is the ischemic endpoint of a dobutamine stress echo. Once it appears, the test has answered its question, and continuing the infusion only extends the ischemia.
Item 1047401
Monitoring and Diagnostics · 14%
A patient has received high-dose nitroprusside for 36 hours for hypertensive emergency. Which finding MOST suggests cyanide toxicity?
Answer and why, all 4 options
A low SvO₂ means tissues are extracting more oxygen, which is the opposite of cyanide toxicity.
Cyanide blocks cellular use of oxygen, so lactate rises while venous oxygen saturation rises because tissues cannot extract oxygen. A rising SvO₂ during high-dose or prolonged nitroprusside is a warning sign.
Hypoglycemia with sweating suggests insulin or sulfonylurea effects, not cyanide. Cyanide causes metabolic acidosis.
Hyperkalemia with peaked T waves is not a feature of cyanide or thiocyanate toxicity. It fits kidney failure or potassium excess.
Item 1048834
Monitoring and Diagnostics · 14%
A patient with stage D HFrEF is being evaluated for a durable LVAD as destination therapy. Which finding is MOST likely to predict poor support after implantation?
Answer and why, all 4 options
A stable creatinine of 1.6 often reflects low cardiac output and may improve once the LVAD restores flow.
Age 74 with a negative frailty screen is acceptable for destination therapy. Frailty, not age, predicts poor outcomes.
A CVP near the PAOP (a ratio above about 0.63) signals right ventricular failure. After LVAD implantation, a failing RV cannot fill the pump, so this predicts poor support and possibly the need for RV support.
A high PAOP with a low cardiac index is the left-sided failure the LVAD is designed to fix. It defines the indication rather than predicting failure.
Item 1049396
Monitoring and Diagnostics · 14%
A mechanically ventilated patient with heart failure has had sedation reduced. The capnogram now shows a notch in the expiratory plateau on every breath. This finding MOST LIKELY indicates
Answer and why, all 4 options
Rebreathing raises the baseline so it no longer returns to zero. It does not notch the plateau.
Secretions narrowing the airway give a shark-fin upslope from slow emptying, not a notch in the plateau.
Esophageal intubation causes the CO₂ waveform to disappear or fade after a few breaths, not a regular notch on every breath.
A notch, or curare cleft, in the expiratory plateau appears when the patient makes a spontaneous breath against the ventilator. It is expected as sedation lightens or neuromuscular blockade wears off.
Item 1050140
Monitoring and Diagnostics · 14%
Cardiac MRI in a patient with ischemic cardiomyopathy shows transmural late gadolinium enhancement in the inferior wall. Revascularization of the RCA is being considered. The nurse recognizes that the inferior wall is
Answer and why, all 4 options
Hibernating myocardium is alive but underperfused and shows little or no enhancement. Transmural enhancement rules it out.
Stunned myocardium follows brief ischemia and has no scar. It would not show transmural enhancement.
Transmural late gadolinium enhancement means the wall is replaced by scar. Viability is unlikely when enhancement exceeds about half the wall thickness, so this segment is not expected to recover after revascularization.
Myocarditis usually causes patchy midwall or subepicardial enhancement, not a transmural pattern in a coronary territory.
Item 1050398
Monitoring and Diagnostics · 14%
A patient with heart failure has thick LV walls on echocardiography and low-voltage QRS complexes. Cardiac MRI shows diffuse, circumferential subendocardial late gadolinium enhancement. The MOST LIKELY cause is
Answer and why, all 4 options
Thick LV walls with low QRS voltage are a classic mismatch that suggests an infiltrative process. Diffuse, circumferential subendocardial enhancement on MRI is the typical amyloid pattern.
Myocarditis causes patchy subepicardial or midwall enhancement, and the walls are not usually thick.
Hypertrophic cardiomyopathy produces thick walls with high, not low, QRS voltage. Its enhancement is patchy and midwall, often at the RV insertion points.
Prior infarction causes enhancement limited to one coronary territory, not diffuse circumferential enhancement. A thickened wall with low voltage also does not fit scar.
Item 1051223
Monitoring and Diagnostics · 14%
Nuclear stress testing shows a reversible defect limited to the lateral wall. For continuous ST-segment monitoring, the nurse should select leads
Answer and why, all 4 options
II, III and aVF view the inferior wall, usually the RCA territory, so they could miss lateral ischemia.
The lateral wall, usually supplied by the circumflex or diagonal branches, is seen by leads I, aVL, V5 and V6. Monitoring those leads catches recurrent ischemia in that territory.
V1 through V4 view the septum and anterior wall, the LAD territory.
V4R views the right ventricle and is used for suspected RV infarction.
Item 1051249
Monitoring and Diagnostics · 14%
After an inferior STEMI, a patient with a PA catheter has PA pressure 24/14 mm Hg, RAP 16 mm Hg, PAOP 12 mm Hg and CI 1.9 L/min/m². Using PA pulsatility index = PA pulse pressure ÷ RAP, the nurse should interpret the result as
Answer and why, all 4 options
1.6 comes from dividing the RAP by the pulse pressure, which inverts the formula.
1.6 is both miscalculated and misread. The low cardiac index and high RAP already argue against a normal RV.
PA pulse pressure is 24 − 14 = 10 mm Hg, and 10 ÷ 16 ≈ 0.6. A pulsatility index below about 0.9 after an inferior MI indicates RV failure, which fits a high RAP, normal PAOP and low CI.
The calculation is right, but a value of 0.6 is low, not normal. Reading it as normal misses RV failure.
Item 1103647
Monitoring and Diagnostics · 14%
Two days after admission for urosepsis, a patient with ischemic cardiomyopathy (LVEF 35%) has new bilateral infiltrates and a PaO2/FiO2 ratio of 140. Fluid balance is +4 L. PAOP is 9 mm Hg, and CVP is 6 mm Hg. The MOST LIKELY cause of the hypoxemia is
Answer and why, all 4 options
Hospital-acquired pneumonia usually starts as a focal infiltrate with fever and sputum. It is not the first explanation for bilateral infiltrates 2 days after sepsis.
New bilateral infiltrates and a PaO2/FiO2 of 140 after sepsis, with a low PAOP and CVP, meet the criteria for ARDS. A normal wedge excludes a cardiogenic cause despite the weak ventricle.
Cardiogenic edema needs high left-sided filling pressures. A PAOP of 9 mm Hg argues against it even with an LVEF of 35 percent.
Atelectasis improves with recruitment and rarely causes severe hypoxemia with diffuse bilateral infiltrates.
Item 2032448
Monitoring and Diagnostics · 14%
Thirty minutes after a PAOP reading, the pulmonary artery catheter balloon is confirmed deflated, but the monitor still shows a damped wedge tracing. The nurse should FIRST
Answer and why, all 4 options
A wedge tracing with the balloon deflated means the catheter has drifted forward into a wedged position. Having the patient cough or turn can dislodge the tip back into the pulmonary artery. If it stays wedged, the provider repositions it.
Reinflating a balloon in a vessel where the catheter is already wedged can rupture the artery or cause infarction.
Advancing pushes the tip further into a small branch, which raises the risk of infarction. The catheter needs to come back, not go in.
Forceful flushing of a wedged catheter can rupture the pulmonary artery. It is never done.
Item 2032626
Monitoring and Diagnostics · 14%
A patient has syncope after being startled awake by an alarm clock. The ECG shows sinus rhythm at 80/min with a QT interval of 480 ms. Using Bazett's formula, the QTc is approximately
Answer and why, all 4 options
At 80 beats per minute the R-R interval is 0.75 s, and its square root is about 0.87. QTc = 480 ÷ 0.87 ≈ 554 ms, which is markedly prolonged and fits syncope triggered by a sudden alarm, as in long QT type 2.
416 ms comes from multiplying by 0.87 instead of dividing, which reverses the correction.
640 ms comes from dividing by the R-R interval instead of its square root.
480 ms is the uncorrected QT. Correction raises it at rates above 60.
Item 2032682
Monitoring and Diagnostics · 14%
A patient with CRT reports more dyspnea. Interrogation shows normal lead thresholds and impedances, sinus rhythm, and biventricular pacing of 88%, down from 98%. Telemetry shows frequent PVCs. The nurse should anticipate
Answer and why, all 4 options
Lead thresholds are normal, so capture is not the problem and more output will not help.
The battery is not mentioned as low, and replacing the generator does nothing for PVCs.
A longer AV delay lets intrinsic conduction win and lowers biventricular pacing further.
Biventricular pacing needs to be close to 100 percent. Frequent PVCs interrupt it, so suppressing them with drugs or ablation restores resynchronization.
Item 2033120
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ECG reading across every section
Rhythm interpretation is not confined to Section IV: dysrhythmias are a Section I diagnosis, and performing and interpreting a 12-lead ECG is one of the testable nursing actions of the revised plan (test plan, p. 3). Questions on this site describe rhythms and 12-lead findings in words; strip images are not part of the set yet.
Reading the numbers correctly
A transducer at the wrong height. AACN's practice alert on pulmonary artery and central venous pressure monitoring references pressures to the phlebostatic axis (fourth intercostal space, half the chest's front-to-back depth) and reads them at end-expiration.
One troponin read as an answer. Injury is a value above the 99th percentile; infarction needs a rise or fall on serial values plus evidence of ischemia (Fourth Universal Definition of Myocardial Infarction, 2018).
BNP on sacubitril/valsartan. Neprilysin inhibition raises BNP, so NT-proBNP is the marker to trend in a patient taking an ARNI, as the 2022 heart failure guideline notes.
An MRI with a device in the chest. An MR-conditional pacemaker or ICD still needs programming and monitoring under the device protocol (HRS 2017 expert consensus on MRI and radiation in patients with cardiac devices), and kidney function matters when gadolinium is planned.
Coffee before a vasodilator stress test. Caffeine blocks the effect of adenosine and regadenoson, so it is held beforehand per the lab's protocol.
Monitoring topics that belong to other pages
Oximetry and capnography in flight, where altitude changes the picture:flight physiology.
In practice, yes: questions give a set of numbers and ask what they show. Learn the ranges from your unit reference or the AACN procedure manual, and practice reading them as a pattern rather than one value at a time.
Is cardiac MRI really on the cardiac medicine exam?
On the revised plan, yes: cardiac MRI and CT are listed under Section IV for exams from November 19, 2026. Expect the nursing side, such as device checks, kidney function and what a finding means for the next step.