窄qrs心动过速卡尔加里紧急课件

Narrow Complex Tachycardias,Moritz Haager PGY-5,Objectives,Develop an approach Review treatment options Dispositon decisions,Perspective,SVT Broad umbrella term for any tachycardia originating above the ventricles Variable underlying mechanisms but basically one Tx approach Ranges from physiological pathological, and benign dangerous Occurs in all age groups Clinical presentation from asymptomatic shock / CHF,When presented with an undifferentiated presentation with a broad DDx and variability in outcome you need an APPROACH,Why should we care?,Morbidity & Mortality Patient discomfort & anxiety Syncopal events (falls) 15% Risk of sudden cardiac death w/ accessory pathway driven arrhythmias Tachycardia-mediated cardiomyopathy LV dilatation w/ impaired LV function,Approach to Tachycardia,Stable or unstable? Assess ABCs, O2, IV, monitors, crash cart to bedside In general if unstable, givem juice Narrow or wide QRS? Regular or irregular? Look at the P waves Relationship to QRS P wave axis / rate P wave morphology(ies) What is the trigger / underlying cause?,Step 1: Stable or Unstable?,Not always black & white Continuum from stable compensated decompensated shock arrest Stability determined by big picture: Symptoms, signs, & vitals Cardio-respiratory reserve Age Co-morbidities Be prepared Any dysrhythmia could potentially deteriorate All therapies are potentially pro-arrhythmic,Step 2: Narrow or wide?,Measure widest QRS on ECG Adults: wide = 0.12 sec (3 small boxes) Kids 0.08 sec (2 boxes),Step 3: Regular or Irregular?,Use calipers or paper Irregularity can be subtle, esp at fast rates Generally Irregular rhythms originate ABOVE the AV node VT is almost never irregular,Step 4: Look at the P waves,P waves present? Is there a P before every QRS? What is the relationship b/w the P and the QRS? What is the P wave rate? Ventricular rate? Is the P wave coming from the SA? N axis: upright in II, negative in aVR Is there 1 distinct P wave morhology?,Diagnostic Trick: 50 mm/s ECG Tracings,Comparsion study of 8 EPs Given 45 ECGs of NCTs printed at 25 mm/s 22: 123126,Final Categorization,Narrow Complex Tachycardias Regular w/ Ps = sinus, a. flutter w/ constant block, Focal atrial tachycardia, AVNRT, junctional tachycardia Irregular w/ Ps = MAT, a. flutter variable block Regular, no Ps = AVRT, AVNRT Irregular, no Ps = a. fib Wide Complex Tachycardias, Tx w/ AV nodal blockers, Rate control +/- rhythm control,Step 5: Underlying Causes,HIS DEBTS H Hypoxia I Ischemia / infarction S Sympathetic excess Hyperthyroid, CHF, pheochromocytoma, excercise D Drugs Anti-arrhythmics, cocaine, amphetamines, caffeine, etc E Electrolytes K+, Ca2+, Mg2+ B Bradycardias Eg. Sick sinus syndrome T Thyroid disease S Stretch Hypertrophy / dilation of atria & ventricles (CHF, valvular Dz),Preciptants vary w/ age, sex, co-morbidities, etc,Clinical Presentations,Typical Sx Palpitations 96% “Dizziness” 75% Dyspnea 47% Fatigue 23% Chest pain 35% Diaphoresis 17% Nausea 13% Neck pounding said to be pathogonomonic,Case,27 yo M w/ palpitations & dyspnea NCT at 160 on ECG c/w PSVT Also tells you he has been “pissin like a racehorse” Does he have diabetes?,Polyuria in PSVT,Loss of AV synchronization Atrial contraction against closed AV valves Elevated atrial pressure & atrial stretch Release of atrial natriuretic peptide polyuria,NB: This is trivia absence of polyuria does NOT exclude Dx of PSVT and you should still check at least a urine for glucose,Case,3 mo F w/ dyspnea & wheeze T 40.5oC, P 190, RR 60, SpO2 88% Mod resp distress on exam w/ wheezes & crackles bilaterally Is this just sinus tachycardia from her fever?,Tachycardia & Fever,Prospective observational study of 490 infants 1 yo Measured HR 43:699-705,Tachycardias: Mechanism,Reentry 50-80% of NCTs Abrupt on-/off-set Do well w/ electricity Enhanced automaticity Typically catecholamines, drugs, lytes, ischemia Gradual on-/off-set Not likely to respond to electricity; Tx underlying cause Triggered dysthythmias Interruption of repolarization by afterdepolarizations Ischemia, drugs, lytes, catecholamines Not likely to respond to electricity; Tx underlying cause E.g. Torsades IV magnesium,Case 2 80 yo F w/ sepsis: Is this sinus tachy?,Maximal sinus tach,220 age = maximum HR 220 -80 = 140 Unlikey this is just sinus tach,Regular NCT: DDx,P waves present: Sinus tachycardia Atrial Flutter AVNRT AVRT Focal Atrial Tachycardia No P-waves AVRT AVNRT Junctional Tachycardia,Consider under PSVT as can be impossible to differentiate on ECG; Tx generally the same,AVNRT vs. AVRT,AV nodal reentrant tachycardia Most common PSVT (60%) Dual AV nodal physiology 2 separate conduction paths in AV node Fast pathway Slow pathway Allow for re-entry circuit w/in AV node,Atrioventricular reentrant tachycardia accessory pathway(s) (AP) = Tracks of conducting tissue outside of AV node, connecting atria & ventricles Re-entry circuit formed by AP & AV node (WPW) 2 or more separate APs (bypass AV node completely),AVNRT,“Typical” AVNRT = 90-95% Anterograde conduction down slow pathway Retrograde conduction up fast pathway If P waves seen RP PR interval,“Atypical” AVNRT is the reverse of what is pictured here,VENTRICLES,ATRIA,AVRT,2 types of AP “concealed” = capable of retrograde conduction only “manifest” = allow anterograde +/- retrograde conduction See “pre-excitation” on ECG,Preexcitation Syndromes,WPW (Wolf-Parkinson-White) PR 100 msec Delta waves in some leads,LGL (Lown-Ganong-Levine) PR 120 msec,WPW & SVT,Orthodromic SVT Anterograde via AV & returns via accessory tract Uses normal conduction system therefore get narrow complex tachycardia,Orthodromic makes up 90-95% of WPW SVTs,WPW & SVT,Antidromic SVT Anterograde conduction from atria to ventricles via accessory path & retrograde flow through AV node Wide complex tachycardia Avoid AV nodal blockers Use procainamide or cardiovert,(5-10% of WPW SVT),WPW & A Fib,Irregular Wide complex tachycardia May see capture & fusion beats Common (30% of WPW pts) & potentially life-threatening AP w/ short refractory period & anterograde conduction near 1:1 conduction VF 0.15 0.39% incidence of sudden cardiac death Do NOT block AV node Channels all impulses down AP & increases risk of VF Use Procainamide or cardioversion,Predictors of Sudden Cardiac Death in WPW,Shortest pre-excited R-R interval during atrial fib 250 ms Hx of symptomatic tachycardia Multiple accessory pathways Ebsteins anomaly* Blomstrm-Lundqvist et al. ACC/AHA/ESC Guidelines for Management of SVA ACC 2003; 42:1493531,*= abnormal tricuspid valve regurgitation & RA enlargement,AVNRT vs. AVRT: Can you tell them apart,Helpful ECG findings Pseudo R in V1 Pseudo S in II, III, aVF specific (but not sensitive) for AVNRT ST elevation in aVR RP 100 ms ST depression 2mm Suggest (not highly specific or sensitive) AVRT,Bottom line = 12-lead lacks 100% accuracy but important to look because AVRT more serious Dx,See Adam Osters talk July 22, 2004 for more detailed explanation,PSVT: Acute Treatment Summary,Unstable DC cardioversion Stable 1) Vagal maneuvers (Class I/ level A) 2) Adenosine (Class I/ level A) 3) CCBs (Class I/ level A) 4) BBs (Class IIb/ level C) 5) Amiodarone (Class IIb/ level C) 6) Digoxin (Class IIb/ level C),Blomstrm-Lundqvist et al. ACC/AHA/ESC Guidelines for Management of SVA JACC 2003; 42:1493531,Cardioversion,Sedation ?1 mg midaz + 100 mcg fentanyl Energy Levels PSVT:- 50 Joules Atrial fibrillation: 200 Joules Atrial flutter: 25-50 Joules Orthodromic WPW: 50 Joules Narrow Complex VT: 50-100 Joules,Adenosine,Actions Coronary vasodilator Transient SA Duration of action 30-40 sec,Adenosine: Adverse Effects,Hot flash / flushing 25% Dizziness 20-50% Chest pain / pressure 20-40% Dyspnea 10-25% Feeling of impending doom 10% Pro-arrhythmia / blocks 10%,75% of pts will experience side effects w/ adenosine,Adenosine: Pro-arrhythmic Effects,Significant literature reports A fib, VF, Transient sinus arrest / asystole, Torsades de pointes Prospective observational ED study 160 consecutive pts given adenosine Overall 21 (13%) pts had pro-arrhythmic s/e Prolonged AV block (4sec) 11 (7%) Atrial Fib 2 (1%) Non-sustained VT 8 (5%) All resolved spontaneously; no serious outcomes,Euro J Emerg Med 2001; 8: 99-105,Pearls,Adenosine CAN convert some VT, giving it to “diagnose” SVT w/ aberrancy is misguided Wide & irregular think WPW + A fib NO AV nodal blockers Amiodarone may not be ideal Procainamide is the drug of choice,Adenosine: Drug Interactions,Theophylline s dose requirement Dipyridamole s dose requirement Carbamazepine potentiates adenosine-induced heart block CCBs / BBs Potentiate hypotension & bradycardia,Adenosine Dosing,DBRCT of 201 pts w/ PSVT: Adenosine Dose Conversion Rate 3 mg 35.2% 6 mg 62.3% 9 mg 80.2% 12 mg 91.4% P0.001 for all doses c/w placebo All administered through PIV,DiMarco et al. Ann Intern Med 1990; 113: 104-110,Practical Pearl,Adenosine administration Want to get it in as fast as possible Use 2 syringes w/ 18g needles one w/ adenosine Other w/ 10 cc NS Put both needles into IV access port Push the adenosine w/ one hand and chase immediately w/ the NS w/ the other NB: want an IV in the AC if at all possible,Adenosine via Central Line,Appears to have increased success rate Observational study of 200 pts w/ PSVT induced in EP lab found 99% success rate w/ 12 mg via femoral line Strickberger et al. Ann Intern Med 1997; 127: 417-422 Randomized Cross-over study of 30 pts given adenosine via PIV or central line success rate w/ 3 mg was 77% when given via central line vs. 37% via PIV McIntosh-Yellin et al. JACC 1993; 22:7415 Case reports of more severe S/E via central line (felt to be dose-related),Case 4,31 yo F w/ PSVT Vagal maneuvers fail 6 mg adenosine IV no response 12 mg adenosine IV slows down briefly What now? Would you give her 18 mg of adenosine?,High Dose Adenosine,Background ACLS: 6 mg, then 12 mg x2 if unsuccessful FDA approves use up to 12 mg Literature reports of uses up to 25 mg What about higher doses? Randomized cross-over comparison of of 31 pts w/ AVNRT/AVRT in EP lab given 12 P = 0.103) No significant increase in adverse effects may have been underpowered to find difference,Weismueller et al. Deutsche Med Wochenschrift 2000. 125: 961-69,Calcium Channel Blockers,2nd line agents in PSVT Verapamil 1st dose: 2.5 5 mg IV over 2 min 2nd dose (30 min later): 2.5 10 mg IV over 2 min (to max of 20 mg) NB: CONTRAINDICATED in 1yo (risk of EMD), wide QRS, or hypotensive pts, CHF, or WPW Diltiazem 1st dose: 0.25 mg/kg IV over 2 min 2nd dose (15 min later): 0.35 mg/kg IV over 2 min followed by gtt of 5-15 mg/h Generally felt to be safer than Verapamil but same cautions apply,What about Verapamil?,RCT of 122 pts w/ PSVT treated w/ either adenosine or Verapamil NS difference in conversion to NSR 86.0% (52/60) vs. 87.1% (54/62), p=NS Adenosine worked much faster 34.2 +/- 19.5 sec vs. 414.4 +/- 191.2 sec, P 0.0001 Cheng KA Zhonghua Nei Ke Za Zhi 2003; 42(11): 773-6,Adenosine vs Verapamil,DiMarco et al. Ann Intern Med 1990; 113: 104-110,DBRCT of 70 pts w/ PSVT,Adenosine vs. Verapamil,Retrospective study of 106 pts w/ PSVT treated w/ adenosine or verapamil No sig difference in overall efficacy Logistic regression found Adenosine worked better w/ faster HR Verapamil had better success w/ slower HR,Interesting study, but hypothesis-generating at most; needs prospective, randomized investigation,Euro Heart J 2004; 25: 13101317,Case,78 yo F presents w/ NCT Hx of PSVT ECG looks identical Had severe side effects w/ adenosine previously & refuses repeat Does not want to be shocked either When you ask for Verapamil the nurse points out her pressure is only 88/65 What can you do?,Calcium pre-Tx to prevent CCB-induced hypotension,Verapamil = vasodilator + myocardial depressant Get some decrease in BP (5-40 mm Hg) in up to 75% pts when given via IV route No RCTs looking at Ca2+ pre-Tx 6 trials totalling 322 pts suggest pre-Tx blunts Verapamil-induced decrease in BP Ca gluconate 1g IV over 5 min appears to be a reasonable choice Ann Pharmacother 2000; 34: 622-9.,NB: No studies exist on Ca2+ pre-Tx for IV Diltiazem,PSVT: Chronic Tx,Pts w/ frequent episodes / severe Sx Drugs CCBs B-blockers Digoxin Other antirhythmics Pill-in-pocket approach Dilitiazem 120 mg PO + propranolol 80 mg PO appears to work best Rarely get hypotension or bradycardia Decreases ED visits Catheter ablation techniques in EP lab Curative in 90% of pts becoming 1st line,May be reasonable to start in ED, but need reliable F/U,Better left to cardiology or EP,Pediatric PSVT,Sx may go unnoticed higher risk of M & M Higher rate of structural heart Dz Should all have cardiac w/u Tx options are more age & lesion-dependant,Pediatric Sx Suggestive of SVT in Infants,Symptoms Abrupt onset of Sx Poor feeding / Vomiting Irritability Diaphoresis Pallor May present in CHF w/ prolonged (12-24h) Hx of tachycardia,Signs HR 220 Minimal beat-beat variability Signs of CHF Pulmonary edema Cardiomegaly Hepatomegaly,Acute Tx of Peds PSVT,Unstable Ketamine 1-2 mg/kg IV for sedation, then DC cardioversion w/ 1-2 J/kg Stable 1) Vagal maneuvers Dive reflex ice to face Avoid carotid massage 2) Adenosine 0.1 mg/kg IVP; repeat 0.20-0.25 mg/kg 3) Verapamil 0.1-0.3 mg/kg IV over 2 min Contraindicated in 1yo (risk of EMD) 4) Amiodarone, propfenone, sotalol,Paediatr Drugs 2000; 2 (3): 171-181,Chronic Tx of Peds PSVT,Refer to cardiology for w/u Order echo & holter Very young may need admission Drug Tx Esp young kids where recurrence may go unnoticed Drug choice depends on age, underlying rhythym, physician preference Digoxn, BBs, sotalol, propafenone, flecainide etc Invasive EP Tx Catheter ablation is safe and highly effective (90%) Becoming Tx of choice in older kids,Paediatr Drugs 2000; 2 (3): 171-181,Disposition of NCT pts,Peds Young, or hemodynamically