Emergency Medicine · Year 3 · from Emergency Medicine
Case 2: Unstable Ventricular Tachycardia
Patient Demographics
- Age: 55 years
- Sex: Female
- Occupation: Office administrator
Chief Complaint
"My heart is racing and I feel like I'm going to pass out."
History of Present Illness
A 55-year-old female presents with sudden onset of palpitations and lightheadedness that began 20 minutes ago. She has a history of "heart problems" and takes "heart medications" but cannot recall the names. She feels weak, has mild chest discomfort, and nearly fainted in the waiting room.
Initial Assessment
ESI Level: 1 - Unstable tachyarrhythmia
Vital Signs:
- Heart rate: 188 bpm, regular
- Blood pressure: 76/48 mmHg
- Respiratory rate: 24 breaths/min
- SpO2: 94% on room air
- GCS: 14 (oriented but confused)
Cardiac Monitor:
- Wide complex tachycardia
- QRS duration ~160ms
- Regular rhythm
Rhythm Analysis
ECG Characteristics:
- Rate: 188 bpm
- Regular wide complex tachycardia
- QRS >120ms (wide complex)
- AV dissociation present
- Fusion beats noted
Diagnosis: Monomorphic Ventricular Tachycardia
Stability Assessment
UNSTABLE - Immediate cardioversion indicated:
- Hypotension (SBP <90)
- Altered mental status
- Signs of hypoperfusion
- Chest discomfort
Management
Immediate Actions:
- IV access established
- Pads placed in anterior-lateral position
- Procedural sedation: Etomidate 0.2 mg/kg IV push
Synchronized Cardioversion:
- Energy: 100J biphasic (synchronized)
- Successful conversion to sinus rhythm on first shock
Post-Cardioversion ECG:
- Sinus rhythm at 78 bpm
- QRS 110ms (baseline LBBB)
- QTc 480ms
- Old anteroseptal infarct pattern
Post-Cardioversion Vitals:
- BP: 118/72 mmHg
- HR: 78 bpm
- Mental status: Alert, oriented
- Chest discomfort resolved
Further Workup
Labs:
- Troponin: 0.08 ng/mL (mildly elevated)
- K: 3.2 mEq/L (low)
- Mg: 1.6 mg/dL (low-normal)
- BNP: 580 pg/mL (elevated)
Echocardiogram:
- EF 25%
- Anteroseptal and apical akinesis
- Dilated LV
History (from family):
- Prior MI 5 years ago
- Known cardiomyopathy
- On metoprolol, lisinopril, furosemide
- Recently ran out of medications
Diagnosis
Monomorphic Ventricular Tachycardia secondary to:
- Ischemic cardiomyopathy (scar-mediated reentry)
- Hypokalemia (medication non-compliance)
Hospital Management
- Telemetry monitoring
- Amiodarone loading (150mg IV, then infusion)
- Potassium and magnesium repletion
- Resume GDMT medications
- Cardiology consultation for ICD evaluation
Disposition
- ICU admission for monitoring
- Discharged day 4 with ICD implanted
- Outpatient EP follow-up
Teaching Points
- Wide complex tachycardia = VT until proven otherwise: Especially with cardiac history
- Unstable = immediate cardioversion: Don't delay with medications
- Synchronization is critical: Prevents shock during vulnerable period (R-on-T phenomenon)
- Find and fix reversible causes: Electrolyte abnormalities are common triggers
- ICD for secondary prevention: Anyone surviving VT/VF arrest with structural heart disease
Clinical Image
Image Description: 12-lead ECG demonstrating monomorphic ventricular tachycardia with wide QRS complexes, regular rhythm, and AV dissociation.
Attribution: Image from Wikimedia Commons, ECG showing ventricular tachycardia. Licensed under CC BY-SA 3.0. Source: https://commons.wikimedia.org/wiki/File:Ventricular_tachycardia.png