Ventricular tachycardia (V tach) Flashcards
What defines ventricular tachycardia (VT)?
Rapid firing of >3 PVCs originating below the bundle of His; HR 120-250 bpm.
What are the two subtypes of VT?
Unsustained (<30 sec) and Sustained (>30 sec).
What are the characteristics of unsustained VT?
Lasts <30 sec, >3 beats, generally asymptomatic.
What are the characteristics of sustained VT?
Lasts >30 sec, generally symptomatic.
How is sustained VT further classified?
Monomorphic (same QRS morphology) and Polymorphic (changing QRS morphology).
What is the key distinguishing factor between monomorphic and polymorphic VT?
Monomorphic has uniform QRS complexes, whereas polymorphic has variable QRS morphology.
What are the major risk factors for VT?
Ischemic heart disease, non-ischemic cardiomyopathy, structural heart abnormalities.
How is unsustained VT managed?
Search for underlying etiology and treat reversible causes.
What are the 5 Hs of reversible causes of tachyarrhythmias?
- Hypovolemia
- Hypoxia
- Hydrogen ion (acidosis)
- Hypo-/Hyperkalemia
- Hypothermia
What are the 5 Ts of reversible causes of tachyarrhythmias?
- Toxins
- Tamponade
- Tension pneumothorax
- Thrombosis (pulmonary)
- Thrombosis (coronary)
What is the immediate treatment for pulseless sustained VT?
Immediate defibrillation (unsynchronized cardioversion).
What is the treatment for stable VT with a pulse?
IV amiodarone, or alternatively lidocaine or procainamide.
What is the treatment for unstable VT with a pulse?
Synchronized cardioversion.
What defines an unstable patient in VT?
Altered mental status, confusion, systolic BP <90 mmHg, or chest pain.
What is the long-term management of VT?
ICD placement; medications such as beta-blockers or amiodarone.
What ACLS intervention is needed for pulseless VT?
Follow ACLS algorithm: Immediate defibrillation, CPR, and epinephrine every 3-5 minutes.
What should be done if VT is refractory to initial treatment?
Consider antiarrhythmic infusion (e.g., amiodarone, lidocaine) and consult electrophysiology.
What is Torsades de Pointes and how is it treated?
A type of polymorphic VT associated with prolonged QT interval; treat with IV magnesium sulfate.
Which medications prolong the QT interval and can precipitate polymorphic VT?
Antiarrhythmics (Class IA, III), antibiotics (macrolides, fluoroquinolones), antipsychotics, antidepressants, antiemetics.
What structural heart diseases increase the risk of VT?
Prior MI, left ventricular hypertrophy, arrhythmogenic right ventricular dysplasia, hypertrophic cardiomyopathy.
When is catheter ablation considered in VT?
Recurrent VT despite medical therapy or ICD shocks.
