EKG心電圖入門知識-英文版 2010留學(xué)生-小講課 (2)-總醫(yī)院課件

1、ELECTROCARDIOGRAPHY Bian BoTianjin Medical University General Hospital1Focus of ECGRate and rhythmIshemiaHyperthrophyothers2Questions to answer in order to identify an unknown arrhythmia:1. Is the rate slow (100 bpm)?Slow Suggests sinus bradycardia, sinus arrest, or conduction block Fast Suggests in

2、creased/abnormal automaticity or reentry2. Is the rhythm irregular? Irregular Suggests atrial fibrillation, 2nd degree AV block, multifocal atrial tachycardia, or atrial flutter with variable AV block3. Is the QRS complex narrow or wide?Narrow Rhythm must originate from the AV node or aboveWide Rhyt

3、hm may originate from anywhere3Steps to Interpreting an ECGRateRhythmAxisIntervals (PR, QRS, QTc)Amplitudes, Morphology(P, QRS)ST segmentsT wavesQ waves5Rate - PaperWhat are the time intervals between lines?0.2 sec200 msec0.04 sec40 msecNormal paper speed is 25 mm/sec6Steps to Interpreting an ECGRat

4、eRhythmAxisIntervals (PR, QRS, QTc)Amlitudes, Morphology(P, QRS)ST segmentsT wavesQ waves7 Normal Sinus rhythm features(1) Every P wave is following by a QRS complex; (2) P wave is upright in lead I, II, aVF, V4-V6, inverse in aVR; Same morphology(3)P-R interval: 0.12-0.20sec(4)Normal rate is 60-100

5、 beats/min810First Degree A-V BlockProlonged P-R interval: P-R interval 0.20sec. in adults (varies with heart rate)12Second Degree A-V Block(1) Mobitz type I (Wenckebach phenomenon). The pattern is a progressive prolongation of the P-R interval until a beat is dropped. The first beat after the pause

6、 has the shortest P-R interval, which may or may not be normal.14152nd Degree AV BlockType 1 (Wenckebach)EKG Characteristics:Progressive prolongation of the PR interval until a P wave is not conducted.As the PR interval prolongs, the RR interval actually shortensEKG Characteristics: Constant PR inte

7、rval with intermittent failure to conductType 216(2) Mobitz type IIThere is a fixed numerical relationship between atrial and ventricular impulses, which may be 2:1 (2 atrial beats to one ventricular beat) or 3:1 or 4:1. 17183rd Degree (Complete) AV BlockEKG Characteristics:No relationship between P

8、 waves and QRS complexesRelatively constant PP intervals and RR intervalsGreater number of P waves than QRS complexes20Steps to Interpreting an ECGRateRhythmAxis and Intervals (PR, QRS, QTc)Amlitudes, Morphology(P, QRS)ST segmentsT wavesQ waves21IntervalsSTPRQRSQTNormalPR 0.12 0.20QRS 0.12QT 35mm”27

9、If the initial component of a biphasic P wave (inV1) is largest, this is Right atrial enlargement. Positive component of the P wave in lead V1 or V2 1.5mmIf the height of the P wave in any of the limb leads exceeds 2.5mm(p pulmonale), suspect Right Atrial enlargementRIGHT ATRIAL ABNORMALITY28Steps t

10、o Interpreting an ECGRateRhythmAxis and Intervals (PR, QRS, QTc)Amlitudes, Morphology(P, QRS)ST segments and T wavesQ waves30Types Of ST Segment Depression31The QS complexes, resolving ST segment elevation and T wave inversions in V1-2 are evidence for a fully evolved anteroseptal MI. The inverted T

11、 waves in V3-5, I, aVL are also probably related to the MI. 3233Significant Q Waves An abnormal Q wave is defined by the following criteria：(1)Q duration of 0.04s or greater(2)Q:R ratio=25or greater34Normal Q waves35Abnormal Q Waves36MYOCARDIAL INFARCTIONThe Classic Signs Of An Acute MI In Progress

12、Are :Elevated ST SegmentInverted T WavePresence Of A Q Wave37Anterior-Septal (Left Anterior Descending)38Anterior Lateral (Left Circumflex)39Inferior (Right Coronary Artery)40ST Segment Elevation41Atrial Premature Contractions4243The QS complexes, resolving ST segment elevation and T wave inversions

13、 in V1-2 are evidence for a fully evolved anteroseptal MI. The inverted T waves in V3-5, I, aVL are also probably related to the MI. 444546There are two types of 2nd degree AV Block. In this example of Type I or Wenckebach AV block there are 3 P waves for every 2 QRSs; the PR interval increases until a P wave fails to conduct. This is an example of group beating.47This bizzare wide QRS tachycardia is irregularly irregular, indicative of atrial fibril