Rapid Atrial Fibrillation in a Patient With Reduced Ejection Fraction
Mr. R, 72, has heart failure with reduced ejection fraction (EF 30%) and was admitted two days ago with pneumonia. At 0700 he is alert but says he feels "fluttering and lightheaded." Telemetry shows atrial fibrillation with a ventricular rate of 138–146. BP 104/68, RR 24, SpO2 92% on 2 L nasal cannula, temp 38.1°C. Bibasilar crackles, JVP 10 cm, 2+ pitting edema to mid-shin, weight up 2.4 kg since admission. His home carvedilol was held yesterday for HR 58. He received 1 L 0.9% NaCl yesterday for low urine output and 40 mg IV furosemide at 0600. The hospitalist orders diltiazem 20 mg IV push now, then 5 mg/hr infusion.
1. The diltiazem order is written. What is your judgment about administering it, and what will you do before the dose is due?
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Do not give the diltiazem as ordered without clarification.
Reasoning:
- Diltiazem is a non-dihydropyridine calcium channel blocker with meaningful negative inotropy and is generally avoided in HFrEF (EF <40%). This patient is already volume-overloaded (crackles, JVD, edema, +2.4 kg) and borderline hypotensive.
- The AF is probably secondary - fever/pneumonia, volume, yesterday's fluid bolus. Rate control is not the only lever; treating the trigger matters at least as much.
- His rate has already shown sensitivity to AV-nodal blockade (carvedilol held for HR 58), so a 20 mg push plus an infusion risks profound bradycardia and hypotension.
Before the dose is due:
- Call the prescriber with an SBAR summary and state the concern explicitly; propose alternatives (treat sepsis/volume, amiodarone or low-dose digoxin for rate, cardioversion if unstable).
- Check K, Mg, TSH, and renal function; verify the EF and current antihypertensives.
- If a rate-control agent is started, ensure continuous ECG and frequent BP checks.
- Document the conversation and rationale. If the prescriber insists and the patient remains stable, escalate to the intensivist or house supervisor - preventing a foreseeable harm is the nurse's responsibility, not simply transcribing the order.
2. At 0745: HR 152, BP 84/50, patient confused, knees cool and mottled, SpO2 90% on 4 L. What are your first three actions and why?
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This is an unstable tachyarrhythmia - hypotension, altered mentation, and hypoperfusion signs. Electricity, not drugs, is the treatment.
- Call for help (rapid response/code) and stop the diltiazem infusion.
- Airway/breathing/circulation: high-flow oxygen, BVM at the bedside, continuous SpO2 and ECG, attach defibrillator pads and put the monitor in synchronized mode. Large-bore IV access.
- Prepare for immediate synchronized cardioversion (biphasic 100–200 J for AF), with sedation if he is still conscious and time allows. Do not delay for more fluids or another rate-control drug.
Support the BP with a vasopressor if needed after conversion rather than large fluid boluses - he is volume-overloaded, not dry. Anticipate post-conversion bradycardia or asystole (atropine and pacing pads ready) and re-check the trigger: sepsis, electrolytes, hypoxia, drug effect. Reassess frequently and document the timeline.
3. After successful cardioversion to sinus rhythm at 78, BP 106/66, he asks why he needs "blood thinners" and whether he can go home tomorrow. What teaching and monitoring priorities apply?
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Why anticoagulation: AF of unknown or >48 hours' duration carries a risk of atrial thrombus; converting without anticoagulation risks stroke. He needs therapeutic anticoagulation guided by CHA2DS2-VASc (age, hypertension, heart failure, diabetes, prior stroke/TIA, vascular disease, sex), often with TEE to exclude thrombus if early cardioversion is desired.
Teaching:
- Why the anticoagulant matters even though the rhythm is now normal, and that it is not short-term.
- Bleeding precautions, avoiding NSAIDs, when to call, adherence, and follow-up labs.
Monitoring priorities:
- Recurrence of AF or bradycardia (especially with any AV-nodal agent), post-conversion hypotension, hypokalemia/hypomagnesemia.
- Continued treatment of the driver: pneumonia, oxygenation, and volume - daily weights, strict I&O, diuresis, and watching for over-diuresis.
Discharge timing depends on the infection, oxygenation, ambulation, and a working anticoagulation plan. "Home tomorrow" is unlikely, and he deserves a clear explanation of what has to happen first rather than a vague answer.