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1、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
2、 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 & anxiet
3、y 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
4、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 determ
5、ined 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
6、(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 th
7、e 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 Catego
8、rization,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
9、, 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 syndr
10、ome 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
11、 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 o
12、f 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 s
13、inus tachycardia from her fever?,Tachycardia & Fever,Prospective observational study of 490 infants 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),
