Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Chapter 7 Detailed Answers to Assess Your Understanding 1. b: The lead used to assess the ECG affects the appearance of the QRS complexes. 2. b: In lead II the deflection of the QRS complex is characteristically positive or upright. 3. c: Analyzing the QRS complex helps identify how the electrical impulse is being carried through the ventricles. 4. a: The normal duration of the QRS complex is 0.06 to 0.10 seconds. 5. d: An upright (in lead II) narrow QRS complex indicates that the electrical impulse originated at or above the AV node and was carried through the ventricles in a normal manner. 6. a: The R wave is the first positive deflection in the QRS complex. 7. c: Early beats that arise from the atria produce normal QRS complexes. 8. c: The amplitude of QRS complexes is higher in the precordial leads than the limb leads. 9. c: Intraventricular conduction defect causes the QRS complexes to appear abnormal. It is usually due to right or left bundle branch block. 10. b: Low voltage or abnormally small QRS complexes are seen in obese patients. 11. c: Bundle branch block is the most common cause of intraventricular conduction defect. 12. a: Bundle branch blocks may be partial or complete. 13. d: Aberrant conduction occurs when the impulse reaches one of the bundle branches while it is still refractory. 14. c: Early beats that arise from the ventricles produce QRS complexes that look different than those that arise above or at the AV junction. 15. a: Idioventricular rhythm has wide, bizarre-looking QRS complexes. 16. b: With ventricular tachycardia the QRS complexes are wide and bizarre-looking. 17. d: With the most severe form of AV heart block the QRS complexes are slower than the P wave rate because there is complete blockage of the AV node. 18. b: Ventricular fibrillation is seen as a chaotic wavy line on the ECG. 19. d: Asystole is seen as a flat line on the ECG. 20. a: The extra QRS complexes are originating from the ventricles. 21. c: The most likely cause of the patient’s extra beats is ischemia.