Ventricular tachycardia

1. VENTRICULAR TACHYCARDIA Dr. Y. Sridhar M.D. Consultant Intensivist Dept. of Critical Care Medicine Apollo Health City, Hyderabad

2. Definition Wide complex rhythm QRS>0.12s Rate > 100 (or120) bpm Origin: from one of the Ventricles i.e., distal to the bundle of His. Three or more consecutive beats on a ECG.

3. Classification Duration of Episodes Morphology Symptoms

4. 1.Duration of Episodes Three or More beats on an ECG at a rate >100bpm originating from Ventricles Non Sustained VT : If rhythm self-terminates spontaneously in less than 30seconds Sustained VT : If rhythm lasts > 30seconds (Even if it self-terminates spontaneously after 30s)

5. 2.Morphology Monomorphic VT : same configuration beat to beat. Polymorphic VT : Continually changing QRS morphology Sinusoidal VT :sinusoidal appearance of rhythm Accelerated idioventricular rhythm (AIVR)

6. Monomorphic VT Most common cause : circuit through a region of old MI. Idiopathic VT (less common) No identifiable cause. Right Ventricular outflow tract (RVOT) tachycardia: MC Idiopathic VT LBBB Morphology with inferior axis.

7. Polymorphic VT Causes Active cardiac Ischemia Electrolyte Disturbances Drug Toxicity Familial Torsade de pointes (twisting of points) Waxing and waning QRS amplitude during tachycardia associated with prolonged QT interval

8. Sinusoidal VT: seen in severe electrolyte disturbances Hyperkalemia Hypocalcemia Hypomagnesemia AIVR Wide complex ventricular rhythm at a rate of 40-120bpm Usually hemodynamically stable MC cause :reperfusion arrhytmia in first 12hrs after acute MI or during periods of elevated sympathetic tone. Typically preceded by sinus slowing No treatment necessary. Self terminates.

9. Pathophysiology Monomorphic VT : Increased automaticity of a single point in either left or right ventricle Reentry circuit within the ventricle Polymorphic VT : Abnormalities in ventricular muscle repolarization

10. Etiology Structural Heart Disease : MI, Cardiomyopathies (HCM), Myocarditis Electrolyte Abnormalities : Hypokalemia , Hyperkalemia , Hypocalcemia , Hypomagnesemia Sympathomimetic agents : Ionotropes . Drug toxicity : Digitalis, Methamphetamine, Cocaine Systemic diseases : Sarcoidosis , RA, SLE. Structural Congenital Disorders : Right ventricular dysplasia, TOF

11. Etiology Prolonged QT Interval Acquired : K Channel blocking medication : Quinidine , Erythromycin, Clarithromycin,Haloperidol , Droperidol Type 1A antiarrythmics : sotalol , amiodarone , Congenital : Brugada syndrome Congenital long and short QT syndromes Catecholamingeric polymorphic VT

12. Diagnosis “All WCT is VT until proven otherwise” AV dissociaton : Dissociation of P wave from QRS complex. QRS Concordance : Absence of rS or Rs complex in any precordial lead RS > 100ms Capture beats : Supraventricular beat conducts to ventricle depolarising ahead of the next tachycardia beat Fusion beats : Depolarisation simultanously with excitation from a ventricular focus.

13. BRUGAGADA CRITERIA

14. Ultra simple Brugada Criteria In 2010 Joseph Brugada published simplified criteria Measuring R wave peak time (RWPT) in Lead Ⅱ RWPT > 50ms It measures duration of onset of QRS to first change in polarity

15. Differential Diagnosis SVT with aberrant intraventricular conduction Preexcited Tachycardia (associated with or mediated by accessory pathway) BBB Ventricular paced rhythms

16. Symptoms Chest Pain Light headedness Palpitations Syncope Sudden Cardiac Death (SCD) : Ambulatory ECG records at SCD have shown 50-60% at sustained monomorphic VT as the initial event .

17. Treatment Depends on Hemodynamics Unstable VT Stable VT

18. ACLS Cardiac Arrest Algorithm. Neumar R W et al. Circulation 2010;122:S729-S767 Copyright © American Heart Association

19. Stable VT Anti arrhythmic drug (AAD) therapy Implantable Cardioverter -Defibrillator (ICD) Catheter Ablation Therapy (CAT) Antiarrhythmic surgery

20. Tachycardia Algorithm. Neumar R W et al. Circulation 2010;122:S729-S767 Copyright © American Heart Association

21. AMIODARONE Large volume of distribution & long half life Contraindications Iodine sensitivity Sinus bradycardia Heart block Precautions Incompatible with NS Preferable via CVC Adverse effects Short term : Skin reactions,Brady , hypotension, corneal microdeposits .

22. AMIODARONE Long term : Pulmonary fibrosis, alveolitis , pneumonitis Liver dysfunction..monitor LFT Hypo or Hyperthyroidism (check TFT before starting) Peripheral neuropathy, myopathy , Cerebellar dysfunction. Concomitant Beta and Calcium channel Blockers: Increased risk of bradycardia , AV Block Potentiates effect of Digoxin , Theophylline and Warfarin – Reduce dose

23. Implantable cardioverter -defibrillator (ICD) ICD therapy compared with conventional AAD associated with mortality reduction of 23-55% depending on risk group. Current ICD options: Single chamber Dual chamber Biventricular cardiac resynchronization Multilevel shock discharge for VT or VF Complications: Inappropriate shock discharge Defibrillator storm Infections Exacerbation of HF

24. External Defibrillator Automated external Defibrillator Wearable automatic defibrillator Worn under the clothing Delivers shock whenever VF is detected.

25. Procedure targets origin of VT Useful in recurrent VT or “VT storm”. Catheter is placed into heart chambers through femoral vein Radiofrequency energy is applied which produces a small burn of about 4 to 5mm in diameter Currently recommended in early treatment of VT when AAD are not preferred or tolerated.

26. Figure 2. Mapping of VT. A 3-dimensional real-time map of the ventricle (created during the procedure) merged with a computed tomography scan (obtained before the procedure). Tung R et al. Circulation 2010;122:e389-e391 Copyright © American Heart Association

27. Recurrent VT : Long term Management Risk of recurrence after successful resuscitation : 30-40% Management of Intercurrent diseases Implantable Cardioverter Defibrillator Long term therapy on Amiodarone .

28. Antiarrhythmic surgery Surgical resection of arrhythmogenic focus Cardiac Sympathectomy Aneurysm resection

29. Thank you!