_Complex Tachycardias Calgary Emergency 窄QRS心动过速卡尔加里紧急课件.ppt

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 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 ABC’s, O2, IV, monitors, crash cart to bedside In general if unstable, give’m 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 8yo: wide = 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 EP’s Given 45 ECG’s of NCT’s printed at 25 mm/s asked t