심전도의 기초 전기적 기초
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탈분극 기록의 세 유형
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전극(양극)으로 가까워지는 탈분극파는 양성파로 기록된다.
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전극(양극)에서 멀어지는 탈분극파는 음성파로 기록된다.
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전극과 직각방향으로 향하는 탈분극파는 파가 없거나 아주 작은 파(파형이 아주 낮음)로 기록된다.
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심실 탈분극의 3단계
A normal adult 12-lead ECG
Normal adult 12-lead ECG
The diagnosis of the normal electrocardiogram is made by excluding any recognised abnormality. It's description is therefore quite lengthy.
- normal sinus rhythm
- each P wave is followed by a QRS
- P waves normal for the subject
- P wave rate 60 - 100 bpm with <10% variation
- normal QRS axis
- normal P waves
- height < 2.5 mm in lead II
- width < 0.11 s in lead II
- normal PR interval
- 0.12 to 0.20 s (3 - 5 small squares)
- normal QRS complex
- normal QT interval
- Calculate the corrected QT interval (QTc) by dividing the QT interval by the square root of the preceeding R - R interval. Normal = 0.42 s.
- Causes of long QT interval
- myocardial infarction, myocarditis, diffuse myocardial disease
- hypocalcaemia, hypothyrodism
- subarachnoid haemorrhage, intracerebral haemorrhage
- drugs (e.g. sotalol, amiodarone)
- hereditary
- Romano Ward syndrome (autosomal dominant)
- Jervill + Lange Nielson syndrome (autosomal recessive) associated with sensorineural deafness
- normal ST segment
- no elevation or depression
- causes of elevation include acute MI (e.g. anterior, inferior), left bundle branch block, normal variants (e.g. athletic heart, Edeiken pattern, high-take off), acute pericarditis
- causes of depression include myocardial ischaemia, digoxin effect, ventricular hypertrophy, acute posterior MI, pulmonary embolus, left bundle branch block
- normal T wave
- causes of tall T waves include hyperkalaemia, hyperacute myocardial infarction and left bundle branch block
- causes of small, flattened or inverted T waves are numerous and include ischaemia, age, race, hyperventilation, anxiety, drinking iced water, LVH, drugs (e.g. digoxin), pericarditis, PE, intraventricular conduction delay (e.g. RBBB)and electrolyte disturbance.
- normal U wave
<심전도의 구성요소와 의미>
개요
P파
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정상 동성 P파 (성인)
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|
lead Ⅰ |
lead Ⅱ |
lead Ⅲ |
lead V1 |
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P파 높이(Amplitude)(mV) |
| 평균(mean) |
0.049 |
0.103 |
0.069 |
0.040 |
| 범위(range) |
0.02-0.10 |
0.03-0.20 |
0-0.20 |
0.005-0.060 |
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P파 기간(duration)(초) |
| 평균(mean) |
0.08 |
0.09 |
0.16 |
0.05 |
| 범위(range) |
0.05-0.12 |
0.05-0.12 |
0.12-0.20 |
0-0.08 |
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PR간격(PR interval)(초) |
| 평균(mean) |
0.16 |
0.16 |
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| 범위(range) |
0.12-0.20 |
0.12-0.20 |
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비정상 동성 P파
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이소성 P파
PR 간격
QRS 파
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정상 QRS파
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파형
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비정상 QRS파
ST 분절
T 파
