CASE STUDY: POST MI TORSADE ARREST

1. CASE STUDY:POST MI TORSADE ARREST ALMERO OOSTHUIZEN UCT/US EMERGENCY MEDICINE 1 APRIL 2009

2. PATIENT BACKGROUND • Mrs. AS, 70y female • PMH: • Hypertension, 40py smoker (COPD) • No previous ischemic events • Medication: • Ridaq 12,5mg od • Currently using amoxil and paracodol for ‘flu’ • No allergies

3. PRESENTING COMPLAINT • Presented to VHW ED at 16h10 • 15h00 - Generalised weakness; legs felt numb; vomited twice; appeared confused; could not understand speech or speak clearly • 15h30 – Chest discomfort; sweating; tremulous. Lasted 30min, then came and went • Also c/o leg discomfort ; 2 weeks of productive cough

4. PHYSICAL EXAM 1 • General: • Frail, poor concentration, slightly slurred speech • HR 75 ; BP 140/82 ; Temp 36,7 ; RR 24 ; Hb 11 • CVS: • Regular pulse ; limb pulses not documented ; no failure ; no murmurs ; JVP not documented • Chest: • No abnormalities documented

5. PHYSICAL EXAM 2 • Abd: • No abnormalities documented • CNS • GCS 14 (slightly confused); power both legs 4/5 • Nil more documented

6. INITIAL ECG’S 1

7. INITIAL ECG’S 2

8. INITIAL ASSESMENT • Casualty Officer (2’nd year intern) notes • ?MI ; ?TIA ; ?LRTI • Central question: In light of possible IC event, is it safe to strep patient?

9. INITIAL MANAGEMENT • O2 ; Aspirin 300mg ; Morphine 4mg ; Isordil sl • Trop T (neg) • Casualty officer referred the patient to medical registrar (actually a cosmo) • Recommended they phone GSH cardiology • Said he’d be down as soon as possible • GSH Cardiology • “we don’t give advice re thrombolysis over the phone” AAARGHH! Intern! AAARGHH!

10. THEN… • Patient now comfortable and pain free • Spoke to medics again • Recommended ED hold off on strep until they have reviewed patient

11. 19h00 • Patient became unresponsive (noticed immediately by attending nurse) and pulseless • CPR commenced at once with chest compressions, and patient rushed to resuscitation area (cpr en route, transit time about 20 sec)

12. RESUSCITATION 1 • BVM vent 2:30 high quality chest compressions ongoing • Monitor attached within 40 seconds of initial arrest • Arrest rhythm: Torsade du Pointes • Immediate async. biphasic cardio version at 200J • CPR commenced, adrenalin 1mg IV ordered, but not given yet

13. TORSADE ECG’S

14. RESUSCITATION 2 • During first cycle of chest compressions post shock, patient displayed signs of ROSC • Moaning, moving • Good pulse felt; rhythm = AF with incomplete RBBB at 75bpm • Patient woke up and was conversant within about two minutes, complaining of ‘sore ribs’ • By this time the medic arrived at last

15. SUBSEQUENT CARE • Post resuscitation care consisted of O2 via face mask and ongoing cardiac monitoring • 2g MgSO4 infused IV over 5 minutes • After discussion with the medical consultant, thrombolysis with streptokinase was started once the patient had been transferred to ICU.

16. NEXT MORNING • Stable post strep course in ICU • Bilateral, severe PVD noted • Critical ischemia of right leg • Transferred to GSH ICU • Right leg embolectomy and fasciotomy, with eventual right sided BKA (septic, non healing wound) • Transferred back to VHW on 25-2-2009, and is doing well!

17. FINAL ASSESSMENT • Inferior STEMI with RV extension • Possible intermittent complete AV block with bradycardia • Complicated by Torsade arrest • Post version/strep AF • Acute limb ischemia (right leg) • Initial embolectomy • Eventual right BKA • Probably never had a ‘TIA’

18. PEARLS • ACS patients are not stable patients • They should be intensively monitored • Difficult management decisions on sick or complicated patients like this should be made by the most senior person available • Torsade with arrest is still arrest: initial treatment remains good CPR and early cardio version. Other treatments may then be considered

19. Pause Dependent (Acquired) Drug induced: 1A and 1C antidysrhythmics, phenothiazines, cyclic antidepressants, organophosphates, antihistamines. Electrolyte abnormalities: hypokalemia, hypomagnesemia, hypocalcemia (rarely) Diet related: starvation, low protein Severe bradycardia or atrioventricular block Hypothyroidism Contrast injection Cerebrovascular accident (especially intraparenchymal) Myocardial ischemia

20. OVERDRIVE WHY? • Acquired Torsade is due to prolongation of the QT interval and is usually precipitated by bradycardia • The so-called short-long-short phenomenon • Brady – early ectopic beat (‘escape’) – comp pause – recovery beat with long QT - R on T - Torsade

21. OVERDRIVE WHY? • Speeding up the rate will shorten ventricular repolarisation • This decreases the effective QT (and therefore vulnerable time) interval and decreases the chances of an early ectopic beat • Voila!

22. OVERDRIVE WHAT? • NB: Overdrive to prevent recurrent TdP vs. Overdrive to convert resistant TdP • Electrical overdrive to a ventricular rate of about 100 – 120 • Discussion of technique during lecture • Chemical overdrive with Isoproterenol • 2 to 10 mcg/kg/min • Titrate to increase HR till VT suppressed

23. Adrenergic Dependent Congenital Jervell and lange-Nielsen syndrome (deafness, autosomal recessive) Romano-Ward syndrome (normal hearing, autosomal dominant) Sporadic (normal hearing, no familial tendency) Mitral valve prolapse. Acquired Cerebrovascular disease (especially subarachnoid hemorrhage) Autonomic surgery: radical neck dissection, carotid endarterectomy, truncal vagotomy

24. TORSADE: MANAGEMENT • Unstable: Unsynchronized cardio version • Sync not effective due to variable R wave amplitude, morphology and axis • Other options • Correct precipitant • MgSO4 1-2g IV in 10 ml D5W as a push for everyone (may also consider K supplementation) • Consider lidocaine or amiodarone (effectiveness not demonstrated) • Class 1A and 1C contraindicated

25. REFERENCES • ACLS resource text (ACLS EP) • 5 Minute emergency medicine consult, Rosen and Barkin • Textbook of Emergency Medicine, Rosen and Barkin • Emedicine.com