A 46-year-old woman presented with palpitations and breathlessness. Her ECG showed a wide QRS tachycardia at 300 beats per minute with a changing QRS morphology. This is consistent with polymorphic ventricular tachycardia. Intravenous magnesium is the drug of choice for polymorphic VT related to digitalis toxicity or hypomagnesemia. For stable monomorphic VT, intravenous beta blockers are preferred as the initial treatment. Refractory VT may require additional treatments such as amiodarone, overdrive pacing, or an intra-aortic balloon pump.

1. PHYSICIAN’S MEET ECG of the week Prof. S.SUNDAR’s unit, Dr. N.IDHAYACHANDRAN,PG

2. a 46 year old Rajeswari, a k/c of DCMP Admitted with the c/o palpitations c/o breathlessness BP- 80/? mmHg, pulse - feeble

4. Ventricular rate: 300/min QRS duration: 200 milliseconds P-R interval: 120 milliseconds QRS axis: +30 degree Monophasic & polymorphic QRS complexes

5. WQRS TACH Irregular Regular QRS morphology Changing beat to beat QRS morphology similar Polymorphic VT Preexcited afib QTC prolonged QTC Monomorphic VT

6. Wide QRS Tachycardia VT AB Cond. AP Cond. ( 81% ) ( 14% ) ( 5% )

7. Regular WQRS tachycardia

8. If no AV dissociation for Morphology criteria for VT present both in Precordial leads V1-2 & V6? Yes No VT SVT with aberrant conduction

9. Wide QRS ECG Is this VT : Preexisting WQRS Sinus Tach SVT VT MMVT PMVT Not sure Tt as VT

11. PMVT stop the offending drug. Correct Electrolyte abnormalities IV Mg bolus (1 to 2 g over 10 min followed by continuous infusions) are indicated. Pacing

12. Role of i.v.Magnesium Drug of choice in digitalis-toxicity related arrhythmias hypokalemia-hypomagnesemia related polymorphic VT of proarrhythmia myocarditis Dose 2-4 gm bolus infusion 4-8 gm infusion over 24 hours

13. VT:Normal Heart We prefer IV beta blocker, as the drug of choice. Once acute episode is treated EP consultation is warranted , as most of them can be cured by catheter ablation

14. Refractory VT/ VF ( 1 ) intravenous amiodarone, and Beta blockers ( 3 ) overdrive pacing, ( 4 ) intraaortic balloon pump, and ( 5 ) coronary revascularization

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