Ventricular Tachycardia (VT) Storm is a serious condition requiring multimodal intervention. The definition is largely empirical, with significant variability in the reported literature1. Originally described during the pre-ICD era (1995), it is defined as ≥ 2 hemodynamically stable or unstable episodes of VT within a 24-hour period2. The condition is further characterized by return of the VT rhythm immediately after termination, such as in the case above3, 4. If AICD is present, VT storm is then defined as ≥ 3 ICD shocks or anti-tachycardia pacing events within the span of 24 hours5.
Rapid morphology recognition is needed to identify potentially reversible causes1. The majority (up to 84%) of patients present with monomorphic VT, usually secondary to previous infarct3, 5. Patients with either poly- or pleomorphic VT are more likely associated with reversible etiologies such as acute ischemia, electrolyte abnormalities, and medications (missed or proarrhythmic). Myocarditis and Hypertrophic Obstructive Cardiomyopathy (HOCM) may also contribute to polymorphic VT storm6.
Clinical presentation can vary significantly, ranging from vague complaints (blurry vision and lightheadedness) to chest pain or even cardiac arrest6. ACLS is the mainstay of emergency intervention if hemodynamic instability is present. Correction of reversible causes and ICD reprogramming should occur as necessary, in addition to medical management and synchronized cardioversion. If VT is sustained or returns following a brief interval, the diagnosis of VT storm can be made1.
To minimize risk of poor outcomes, at this clinical juncture many clinicians will escalate care to catheter ablation, left sympathetic ganglion block, and/or sympathetic cardiac denervation7. However, amiodarone and/or lidocaine infusion are medical management options that can be utilized prior to escalation. This is particularly relevant in emergency settings when interventional cardiology and/or cardiothoracic surgery services are not readily available. Antiarrhythmic infusion also bypasses the need for more invasive strategies such as central sympathetic blockade. As this intervention requires neuromuscular paralysis, sedation, intubation, and cooling, it would necessitate ICU admission4. Of note, patients receiving lidocaine infusion must be monitored for neurotoxic side effects4.
Following ICD implantation for secondary prevention, early referral for catheter ablation is associated with improved long-term patient outcomes3. In the 2016 VANISH clinical trial, patients experienced decreased VT recurrence, fewer ICD shocks, and a long-term survival benefit if they received catheter ablation (vs. escalation of outpatient AAD therapy)8.
In-hospital mortality can be as high as 19.5%5. 6-month mortality involves an additional 18% of patients, particularly those age > 50 and with prior infarct5. Up to 46% experience VT recurrence at 6 months; patients with LVEF < 30% are at greatest risk5.
In conclusion, patients without AICDs presenting with VT Storm require stabilization to avoid escalation of care involving more invasive procedures. Amiodarone and lidocaine may be administered as infusions in addition to boluses to achieve patient stabilization in the emergency setting.