1 / 10

Electrocardiographs ECG part2

Electrocardiographs ECG part2. Elements of the ECG: P wave: Depolarization of both atria; Relationship between P and QRS helps distinguish various cardiac arrhythmias Shape and duration of P may indicate atrial enlargement PR interval: from onset of P wave to onset of QRS

javen
Download Presentation

Electrocardiographs ECG part2

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ElectrocardiographsECGpart2

  2. Elements of the ECG: • P wave: Depolarization of both atria; • Relationship between P and QRS helps distinguish various cardiac arrhythmias • Shape and duration of P may indicate atrial enlargement • PR interval: from onset of P wave to onset of QRS • Normal duration = 0.12-2.0 sec (120-200 ms) (3-4 horizontal boxes) • Represents atria to ventricular conduction time (through His bundle) • Prolonged PR interval may indicate a 1st degree heart block • QRS complex: Ventricular depolarization • Larger than P wave because of greater muscle mass of ventricles • Normal duration = 0.08-0.12 seconds • Its duration, amplitude, and morphology are useful in diagnosing cardiac arrhythmias, ventricular hypertrophy, MI, electrolyte derangement, etc. • Q wave greater than 1/3 the height of the R wave, greater than 0.04 sec are abnormal and may represent MI

  3. ST segment: • Connects the QRS complex and T wave • Duration of 0.08-0.12 sec (80-120 msec) • T wave: • Represents repolarization or recovery of ventricles • Interval from beginning of QRS to apex of T is referred to as the absolute refractory period • QT Interval • Measured from beginning of QRS to the end of the T wave • Normal QT is usually about 0.40 sec • QT interval varies based on heart rate

  4. Lead I Lead II Lead III Lead aVR Lead aVL Lead aVF V1-V6 Standard Lead System Lead I: LA- RA Lead : LL - RA Lead III: LL - LA V1-V6: Locations of chest electrode:

  5. It Consists of * electronic part 1-Preamplifier 2-Power amplifier to move the galvanometer pen 3- 1 mv calibration source 4- Protecting circuits * Stylus ECG Machines

  6. 1 mV Lead selector Amplifier Stylus Galvanometer Gear Train Motor

  7. Patient cables • Most important part • Most frequently at fault. • There are several different cables: Some constructed of two pieces: more expensive but more economical in the long run • One piece construction • Most ECG cables are made of shielded wire

  8. Standard cable color code

More Related