CARDIOLOGY
POLYMORPHIC VT
PromptECG interpretation
ResponseVery broad QRS, Tachycardia (The usual VT stuff from above)
Shifting axis
Note Polymorphic VT – form of VT in which multiple ventricular foci, resultant QRS complex varies in amplitude, axis, and duration. Most common cause is MI
TdP is a specific type of Polymorphic VT occurring in context of QT prolongation.
Shifting axis
Note Polymorphic VT – form of VT in which multiple ventricular foci, resultant QRS complex varies in amplitude, axis, and duration. Most common cause is MI
TdP is a specific type of Polymorphic VT occurring in context of QT prolongation.
PromptCauses polymorphic vt
ResponseDrugs
Electrolytes
- Sotolol, lots of others (see below)
Electrolytes
- Hypokalaemia, hypomagnesaemia – eg: Secondary to vomiting
- Dilated cardiomyopathy, cardiac amyloid
- Congenital long QT
PromptDrugs that cause TdP (Long QT)
ResponseClass 1A (procainamide), 1C (flecainide) and class 3 (sotalol, amiodarone) antiarrhythmic drugs
Phenothiazides
TCA’s
Antibiotics eg: erythromycin
Organophosphates
Drugs causing long QT
Antiarrhythmics – Amiodarone, sotolol
Antimicrobials – ciprofloxacin, clarithromycin, erythromycin
Antidepressants – Amitripityline (Other TCA’s), Sertraline (Other SSRI’s)
Antipsychotics – Haloperidol, droperidol, others
Antiemetics – Ondansetron
Anti- Pain - Methodone
Phenothiazides
TCA’s
Antibiotics eg: erythromycin
Organophosphates
Drugs causing long QT
Antiarrhythmics – Amiodarone, sotolol
Antimicrobials – ciprofloxacin, clarithromycin, erythromycin
Antidepressants – Amitripityline (Other TCA’s), Sertraline (Other SSRI’s)
Antipsychotics – Haloperidol, droperidol, others
Antiemetics – Ondansetron
Anti- Pain - Methodone
PromptManagement of unstable patient with polymorphic VT
ResponseMagnesium 10 mmol over 5 mins
Synchronised DC cardioversion 200J
Seek and treat cause (eg: hypokalaemia), cease offending agents
Synchronised DC cardioversion 200J
Seek and treat cause (eg: hypokalaemia), cease offending agents
PromptMgmt esiclation if not responding/reverting to polymorphic VT
ResponseChemical pacing – Isoprenalin 5-30 mics/min, aiming for HR>100/min (Too fast for R on T to occur so doesn’t degrade to TdP)
Electrical overdrive pacing – Synchronised pacing at rate 100/min – increase current to achieve electrical and mechanical capture – Remember that VT storm lady who just kept arresting, then we put a pacing wire in and boom. Golden. Discharged neurologically intact a week later.
Electrical overdrive pacing – Synchronised pacing at rate 100/min – increase current to achieve electrical and mechanical capture – Remember that VT storm lady who just kept arresting, then we put a pacing wire in and boom. Golden. Discharged neurologically intact a week later.
PromptRisk factors for long QT (non pharmacologic)
ResponseAge
Female gender
Congenital QT prolongation
LV failure
Recent cardioversion
Metabolic abnormalities
Hypomagnesaemia
Hypokalaemia
Hypocalcaemia
Hepatic dysfuntion
Female gender
Congenital QT prolongation
LV failure
Recent cardioversion
Metabolic abnormalities
Hypomagnesaemia
Hypokalaemia
Hypocalcaemia
Hepatic dysfuntion