Non-Sustained Ventricular Tachycardia (NSVT) Flashcards
What is Non-Sustained Ventricular Tachycardia (NSVT)?
Non-sustained ventricular tachycardia (NSVT) is an ectopic ventricular rhythm with wide QRS complex (120 milliseconds or greater), rate faster than 100 bpm, lasting for at least 3 beats that spontaneously resolves in less than 30 seconds.
What are the risk factors for NSVT?
- History of CAD
- History of cardiomyopathy
- History of idiopathic dilated cardiomyopathy
- Left ventricular systolic dysfunction
- Long QT syndrome
- Brugada’s syndrome
- Drug toxicity
- Chagas’ disease
What are the signs of NSVT?
- Tachycardia
What are the symptoms of NSVT?
- Asymptomatic presentation
- Palpitations
- Dizziness
- Lightheadedness
- Pre-syncope
- Syncope
What investigations should be ordered for NSVT?
- ECG
- Electrolyte panel
- Troponin
- CK-MB
Why investigate using ECG?
Positive findings confirm the diagnosis of NSVT.
Wide QRS complex (120 milliseconds or greater), rate >100 bpm lasting for 3 or more beats, spontaneously resolving in <30 seconds.
Why investigate using electrolyte panel?
Electrolyte abnormalities may trigger NSVT in patients with or without cardiac disease.
May show normal, hypokalaemia, hyperkalaemia, or hypo-magnesaemia.
Why investigate using troponin?
Clinical suspicion for ischaemia should prompt testing of myocardial bio-marker assays, as they provide useful confirmatory information.
May be elevated in MI.
Why investigate using CK-MB?
Clinical suspicion for ischaemia should prompt testing of myocardial bio-marker assays, as they provide useful confirmatory information.
May be elevated in MI.
How are the asymptomatic NVST cases treated?
NSVT is by definition a self-terminating event, and therefore usually no specific treatment is indicated. Rather, treatment is directed at any existing heart condition.
How are NSVT cases treated?
On the rare occasion that NSVT produces symptoms in the absence of cardiac disease, medication or catheter ablation may be required.
Medical treatment options include beta-blockers or calcium-channel blockers (usually used when beta-blockers are contraindicated, e.g., asthma) as first-line therapy.
Catheter ablation may be considered early in the treatment course if the arrhythmia proves resistant to these drugs.
Antiarrhythmics such as flecainide or propafenone may be used in patients who fail therapy with beta-blockers and/or calcium-channel blockers who are not candidates for catheter ablation or in whom catheter ablation is ineffective.
What are the complications of NSVT?
- Sudden cardiac death
- Cardiomyopathy
- Ventricular fibrillation
What differentials should be considered in NSVT?
- SVT with aberrant conduction
How does NSVT and SVT with aberrant conduction differ?
Differentiating signs and symptomsL
- None
Differentiating investigations:
- ECG, electrophysiological study: failure to meet criteria for NSVT; absence of fusion capture beats; absence of AV dissociation
