Arrhythmias part 2 Flashcards
What is ventricular tachycardia?
Rapid ventricular beating that may result in inadequate ventricular filling
VT patho
- occurs due to rapid, recurrent ventricular depolarisation from a focus within the ventricles
- due to scarring of ventricles from MI
Consequences of VT
loss of consciousness, loss of cardiac output and ultimately cardiac arrest.
Life threatening
What is polymorphic VT
due todepolarisation of multiple foci within the ventriclesleading to variable QRS complexes
secondary to myocardial ischaemia
What is Torsades de pointes
subtype of polymorphic VTthat is characterised by ventricular tachycardia that ‘twists’ around the isoelectric line
subtype occurs secondary to aprolonged QT interva
Clinical manifestations
- Breathlessness
- Chest pain
- Palpitations
- Dizziness/ syncope
- Hypotension
- Cardiac arrest
ECG for VT
rapid, broad-complex tachycardia (QRS >120 ms)
Management for VT
- Consider up to 3 synchronised shocks
- IV amiodarone infusion
- Beta blockers: for management of symptoms
What is Long QT syndrome
A prolonged QT interval is the ECG finding of prolonged repolarisation of the muscle cells in the heart after a contraction
RFs for Long QT
Romano Ward Syndrome
Jervell-Lange-Nielsen syndrome
Electrolyte imbalance
QT- prolonging drugs
Normal corrected QT interval
<430 ms in malesand<450 ms in females.
Long QT syndrome pathophysiology
ion channels involved in myocardial ventricular repolarisation are affected, resulting in aprolonged QT intervalon an ECG.
S + S of long QT
-
Signs of Andersen-Tawil syndrome
- Micrognathia
- Low-set ears
- Widely spaced eyes
- Dizziness
- Palpitations
- Dyspnoea
ECG for Long QT
- ECG:to identify the presence of long QT syndrome (QTc >430 ms in males and >450 in females)
- Serum electrolytes:especially potassium, magnesium, and calcium
Management for LONG QT
- Conservative: avoid precipitating factors (e.g. stress and exercise), correct electrolyte imbalance, cease QT-prolonging medication
- Beta-blocker: Propanolol
