1. Peri-op Cardiac Arrhythmias, cause, recognition and treatment. w Presented by R1 林至芃 2000.5.04

2. Case presentation w 77y/o female, DM poor control, HTN….. w Necrotizing pneumonia with respiratory failure s/p intubation and ventilator support w hemopneumothorax, poor chest tube function came to OR for VATS. w PSVT with hemodynamic compromise successfully stopped by esmolol+phenylnephrine Af with RVR after PSVT stopped.

3. Peri-op Cardiac Arrhythmias w High incidence (15%-85%) w healthy individuals w supraventricular, ventricular, short run VT w from infant to eighties. w Less than 1% are life-threatening.

4. Peri-op Cardiac Arrhythmias w Physiology:1.Action potential. 2.Pace maker cells. 3.Conduction system. w Electrophysiology of arrhythmia. w Anti-arrhythmic drugs. w Management of perioperative arrhythmia.

5. Action potential of myocardium phase 0,1,2 => absolute refractory phase late3, 4=>relative refractory

6. Pacemaker cells and myocardium

7. Classification of arrhythmia w Bradyarrhythmia: sinus bradycardia AV block- 1 0 degree, 2 0 degree (Mobitz type I, Mobitz type II) 3 0 (complete) w Premature complexes: PACs, PJCs, PVCs.

8. Classification of arrhythmia w Tachycardia: A. Narrow complex tachycardia 1.Sinus tachycardia 2.Atrial tachycardia 3.AV junctional tachycardia 4.AVNRT 5.AVRT 6. W-P-W syndrome 7.Atrial fibrillation 8.Atrial flutter B. Wide complex tachycardia 1.SVT with aberration 2.In WPW 3.AIVR 4.VT 5.VF 6.Torsades de pointes.

9. Sinus bradycardia w PR<60/min w increased vagal tone, antiarrhythmic drugs effect, ischemia, primary sinus node disease w 0.2-2 mg atropine, pacing.

10. AV block w 1 0 AV block: PR>200ms, conduction delay in AV node w 2 0 -Mobitz type I, delay within AV node, inferior or posterior ischemia w 2 0 -Mobitz type II, His-Purkinje system, anterior distribution. w 3 0 -complete heart block, congenital, infarction or ischemia, drug, idiopathic degeneration.

11. Premature complexes-PVCs w most common arrhythmia w occur with and without heart disease w adult males, 60 percent. w up to 80 percent previous MI, if frequent (>10/h) or/and complex (couplets) =>increased mortality. w wide (usually >0.14 s), bizarre QRS complexes no preceding P waves

12. Premature complexes-PVCs w No cardiac dz: isolated asymptomatic VPCs, regardless of configuration and frequency, need no treatment. w Beta- blockers (daytime or under stressful situations,MVP, thyrotoxicosis. w In AMI, first 24 h Temporary prophylactic antiarrhythmic therapy with lidocaine or procainamide.

13. Narrow QRS tachycardia w Sinus tachycardia: Tx targeted at underlying w Atrial tachycardia: pulmonary dz => MAT, theophylline digitalis toxicity=> PAT with 2 0 AV-block => lidocaine, beta-blocker w AVNRT: most common PSVT w orthodromic AV reciprocating tachycardia

14. Narrow QRS tachycardia w WPW syndrome: preexcitation, delta wave. Af with WPW=>VF w Af: most common sustained tachycardia (10% of older than 75y/o) acute Af with RVR, unstable=> DC shock chronic AF, for RVR control=> Ca blocker, beta blocker are rapid and effective digoxin for LV dysfunction. w A flutter: sawtooth pattern baseline, esp II, III, aVF

15. Wide QRS tachycardia w SVT with aberration w AIVR: terminal purkinje, myocardium. Acute MI, inflammatory process 60-130/min, atropine, overdrive pace w VT: most common life-threatening form. CAD, CM, other inflammatory process D/D: SVT with aberration. Tx: synchronized DC shock procainamide, lidocaine, amiodarone

16. Wide QRS tachycardia w VF: immediate unsynchonized DC shock w Torsades de Pointes: polymorphic VT. Tx: magnesium sulfate.

17. Electrolyte Imbalance and pH w Low Potassium (acute/severe) => ventricular arrhythmia w Sodium => not significant w Magnesium => low ->interfere Na-K pump produce primarily SVT =>2 gm despite actual Mg level to reduce post-CPB SVT w arrhythmias are not major seguela of acute pH change.

18. Anesthesia w Most anesthetics are calcium antagonistic => anti-arrhythmic w halothane sensitize heart to circulating or exogenous catecholamines. w Potentiate myocardial suppression effect of antiarrhythmic agent.

19. Classic anti-arrhythmic drugs w I: membrane stabilizer, block fast Na channels Ia: quinidine, procanamide => not available!! Ib:lidocaine=>useful for all ventricular arrhythmia SVT with aberration=> harmless! 2% lidocaine, 100mg/amp 20mg/ml a.post-defib VT/VF 1.5mg/kg b.Stable VT, undetermined wide QRS tachycardia 1-1.5 mg/kg 5-10 min 1/2 dose repeat x 2-3 c.post DC or post-MI 的警示性 VPC (>6/min, R-on-T, couplets or short-run, polymorphic) 0.5mg/kg (may repeat x3)

20. Classic anti-arrhythmic drugs w II: beta-blocker effective in all tachycardic arrhythmia even in LV dysfunction when RVR superimposed w III: prolong repolorization, effective in all arrhythmia, including bupivacaine induced arrhythmia amiodarone (150mg/3ml/amp) for refractory, repetitive VT/VF Loading 150mg over 10 min than 1mg/min Cx: hypotension, QT-prolong!

21. Classic anti-arrhythmic drugs w IV: calcium channel blocker effective in SVT, Af, AF. Contraindicated in narrow QRS Af with known WPW! Ineffective at ventricular arrhythmia!! Verapamil (Isoptin 5mg/ml/amp) a. systolic >90 mmHg b. AF, Af, MAT: effectively decrease ventricular resoponse!(esp diltiazem, less myocardium suppression ) c. 2.5-5mg slowly push for 2 min, 15-30 min repeat, Max 30mg, may pre-treat CaCl2

22. Other anti-arrhythmic drugs w Adenosine(6mg/2ml/vial) for PSVT (I) 6mg -> 12mg rapid push!! transient bradycardia, even asystole (max15 sec) w Digoxin(0.25mg/1ml/amp) AF, Af, PSVT : ventricular rate control 0.25-0.5 mg slow push for loading onset 5-30 min, peaking 1.5-3 hr be careful: HypoK

23. Other anti-arrhythmic drugs w MgSO 4 : (2gm/20ml/amp) a. Torsade de Pointes or refractory VF/VT b. Post-CPB SVT c. post-MI ventricular arrhythmia d. 1-2 g solwly push e. hyperMg, decrease DTR, hypotension, resp muscle paralysis, f. antidote:CaCl2

24. What we forget?! w Defibrillator w TCP w Bradycardia w Call for help!?

25. Thanks for your attention!