Ventricular Tachycardia
15/11/10
2010 Resuscitation Guidelines
Life in the Fast Lane ECG’s
PY Mindmaps
= 3 or more VEB at a rate of > 130 beats/min
- > 30 seconds = sustained
- can be monophoric or polymorphic
TYPES
Monomorphic
- most common
- associated with MI
Polymorphic
- QRS at 200 beats/min or more which change amplitude and axis so they appear to twist around the baseline
-> treatment is the same for both
MECHANISMS
- enhanced automaticity (ectopic pacemaker activity)
- enhanced trigger activity
- re-entry
PREDISPOSTING CONDITIONS
Channelopathies (Na+ and K+)
- Lange-Neilsen syndrome (long QT + deafness)
- Romano-Ward syndrome (long QT and no deafness)
- Bugada syndrome
Other electrophysiology effects
- WPW
- catecholamine sensitive polymorphic VT
Drugs that cause QT Prolongation
- clarithromycin
- erythromycin
- metaclopramide
- haloperidol
- TCA
- methadone
- droperidol
Electrolytes
- hypokalaemia
- hyperkalaemia
- hypomagnesaemia
- hypocalcaemia
Hypothermia
Structural heart disease
- LV dysfunction
- coronary artery disease
- MI
- HOCM
DIFFERENTIATING VT from WIDE COMPLEX SVT
Criteria for diagnosis of VT using the 4-step Brugada algorithm:
(i) Is RS complex present in any lead? - if NO the rhythm is VT
(ii) Is the RS duration >100ms in any lead? - if YES then the rhythm is VT
(iii) Is there AV dissociation? (fusion or capture beats) -> if YES then the rhythm is VT
(iv) Is the rhythm morphologically consistent with SVT (looks like RBBB or LBBB)? -> if NO the rhythm is VT
-> fusion beats = complex looks half normal and half abnormal
-> capture beats = normal complex seen
MANAGEMENT
PULSELESS
ACLS protocol
Immediate unsynchronised defibrillation
CPR with minimal interruption (30:2, with 2 minute cycles)
Intubation
O2
IV access
Adrenaline 1mg Q3min
Amiodarone 300mg (following 3rd shock)
Exclude reversible causes (4 H’s and T’s)
CLINICALLY COMPROMISED
Haemodynamically unstable, chest pain, ischaemia, heart failure, VR > 150/min -> synchronised shock (x 3)
O2
IV access
Rapid exclusion of reversible factors (wire, PA catheter in RV, hypoK+ or Mg2+)
Amiodarone 5mg/kg -> infusion
Synchronised DC Shock (50J Bi, 100 Mono)
Consider:
-> procainamide 50mg/min
-> lignocaine 1mg/kg
-> sotalol 1mg/kg
Repeat DC Shock (150 Bi, 360 Mono)
Overdrive pacing
CLINICALLY STABLE
- controversial
- debate between cardioversion and pharmacological treatment
- still a medical emergency as can degenerate into unstable VT and VF
O2
Amiodarone or sotolol
Cardioversion if medical therapy fails (quickly) – will need sedation
Consider pacing if cardioversion no effective
Evaluation and treatment of cause (usually IHD)
If associated with long QT -> consider Mg2+
Jeremy Fernando (2011)