At the Bedside
Start with ABCs, telemetry, and a 12-lead ECG; if unstable, treat the rhythm first and do not delay defibrillation/cardioversion for device questions. Ask exactly what happened: shock count, symptoms before/after shocks, syncope, palpitations, chest pain, dyspnea, fever, recent procedures, trauma, or magnet exposure. Obtain electrolytes, Mg, troponin if ischemia is possible, CBC if infection is a concern, chest x-ray for lead position/device complications, and consider device interrogation early if available.
Determine if the device delivered appropriate therapy: VT/VF shocks are usually appropriate, while AF with RVR, oversensing, lead fracture, or T-wave oversensing can trigger inappropriate shocks. A single shock with symptom resolution and stable vitals still warrants workup for the trigger; recurrent shocks, electrical storm, syncope, chest pain, or hemodynamic instability are admission/ICU-level problems. If the patient is being shocked repeatedly and the rhythm is VT/VF, follow ACLS and consider antiarrhythmics such as amiodarone or procainamide depending on the rhythm and stability.
If the patient is paced by the ICD and there is concern for malfunction, remember that a magnet typically suspends tachy-therapies but does not guarantee pacing support. For infection concerns, look for pocket erythema, pain, drainage, bacteremia, or endocarditis signs; device infection generally requires admission, blood cultures, and specialist consultation.
Determine if the device delivered appropriate therapy: VT/VF shocks are usually appropriate, while AF with RVR, oversensing, lead fracture, or T-wave oversensing can trigger inappropriate shocks. A single shock with symptom resolution and stable vitals still warrants workup for the trigger; recurrent shocks, electrical storm, syncope, chest pain, or hemodynamic instability are admission/ICU-level problems. If the patient is being shocked repeatedly and the rhythm is VT/VF, follow ACLS and consider antiarrhythmics such as amiodarone or procainamide depending on the rhythm and stability.
If the patient is paced by the ICD and there is concern for malfunction, remember that a magnet typically suspends tachy-therapies but does not guarantee pacing support. For infection concerns, look for pocket erythema, pain, drainage, bacteremia, or endocarditis signs; device infection generally requires admission, blood cultures, and specialist consultation.
A Classic Presentation
A 68-year-old man with ischemic cardiomyopathy and a known ICD presents after feeling two “hard thumps” in his chest while watching TV. He is now alert and hemodynamically stable but reports mild chest pressure beforehand and intermittent palpitations. ECG shows a run of nonsustained wide-complex tachycardia; labs reveal low magnesium and a mildly elevated troponin. Device interrogation confirms appropriate shocks for ventricular tachycardia. He is admitted for monitoring, electrolyte correction, ischemic evaluation, and electrophysiology consultation.
Patient Presentation to Attending
How you’d present this patient on the floor
This is a 68-year-old man with ischemic cardiomyopathy and an ICD presenting after two shocks this evening, preceded by palpitations and chest pressure. My main concern is that these were appropriate therapies for VT/VF rather than a simple device issue, because symptoms before the shocks raise concern for an arrhythmic trigger or ischemia. He’s currently awake and stable, and he denies syncope, sustained hypotension, or ongoing chest pain, which makes immediate unstable VT less likely. Exam is reassuring aside from his underlying cardiac disease, and the ECG shows intermittent nonsustained wide-complex tachycardia without STEMI. I’ve sent electrolytes, magnesium, and troponin, placed him on telemetry, and we’re getting device interrogation to determine whether the shocks were appropriate. He’ll need admission for monitoring and trigger management, and if he becomes unstable or goes back into sustained VT we’ll cardiovert and treat per ACLS.
Study Directive
- Draw an ED algorithm for “ICD shock patient”: stable vs unstable, appropriate vs inappropriate shocks, and when to interrogate the device.
- Memorize the standard amiodarone and procainamide dosing used for VT storm and compare when each is favored.
- Practice interpreting 3 ECGs: VT, AF with RVR, and oversensing/lead noise patterns.
- Review 5 red flags that mandate admission: recurrent shocks, syncope, ischemia, infection, and device malfunction.
- Read a short device-interrogation primer and learn what information the ED should request from cardiology/electrophysiology.
Recent Literature
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Review or guideline 2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society
Defines when ICD therapy is indicated for ventricular arrhythmia/sudden-death prevention and frames ED decisions around shocks, ventricular tachycardia, and need for urgent cardiology/electrophysiology involvement.
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Review or guideline Multidisciplinary Critical Care Management of Electrical Storm: JACC State-of-the-Art Review
Useful for the crashing AICD patient with recurrent shocks, emphasizing immediate stabilization, correction of triggers, antiarrhythmics, sedation, and early electrophysiology/ICU escalation for electrical storm.