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Lesson 1, 2 ELECTROCARDIOGRAPHY. 2010. 05. 27 Ji-Won Kim. Main function of the heart. Pulmonary circuit To oxygenate the blood To remove carbon dioxide Systemic circuit To deliver oxygen to tissues To deliver nutrients to tissues. 동영상. Three types of cells for heart beat. - PowerPoint PPT Presentation
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Lesson 1, 2ELECTROCARDIOGRAPHY
2010. 05. 27 Ji-Won Kim
Main function of the heart
Pulmonary circuit To oxygenate the blood To remove carbon dioxide
Systemic circuit To deliver oxygen to tissues To deliver nutrients to tissues
동영상
Three types of cells for heart beat
Rhythm generators (SA node: pacemaker)
Conductors
Contractile cells (myo-cardium)
심장세포의 전기적 활동
심장세포내에는 많은 이온 (Na+, K+, Ca+, Cl-) 이 세포내외를 이동하면서 전기적 활동
분극 (Polarization) : 흥분하지 않은 휴식상태 . 안정기 탈분극 (Depolarization) : 세포의 흥분 후 일어나는 변화 재분극 (Repolarization) : 다시 안정기 . 전기배열과 이온배열이 원
상태로 되돌아 옴
심장 탈분극의 전도 (Electro-conduction)
Modulation of Heart rate and strength of contraction
Sympathetic ( 교감 ) system Acts as an accelerator, speeding up and
increasing the contractile force of the heart
Para-sympathetic ( 부교감 ) system Acts as a brake, slowing down the heart
Electrocardiogram
P wave Result from atrial depolarization
QRS wave Result of ventricular depolarization
T wave Result from ventricular repolarization
Electrocardiogram
PR interval The time it takes for the impulse sent from the SA node
to travel to the ventricles
PR segment The time of AV nodal delay and transmission to the
ventricles
Experimental objectives
To become familiar with the electrocardiograph
Electrical events vs. mechanical events
To observe rate and rhythm changes Associated with body position and breathing
Lead
Spatial arrangement of two electrodes on the body
Electrode placement Positive and negative electrodes Defines recording direction of the lead
Lead axis (vector) Determined by the direction going from the
negative to positive electrode
ECG recorder Computes the voltage difference between the
positive and negative electrodes
표준사지유도 (Standard bipolar limb lead)
두 전극 사이의 전압의 차를 절대치로 기록하는 양극 유도방식 심장을 전방에서 종축 ( 종단면 ) 으로 바라보는 방향
Einthoven’s Triangle
Chest(Precordial) lead( 흉부유도 ) : Horzontal plane V1, V2, V3, V4, V5, V6
V1: right 4th intercostal spaceV2: left 4th intercostal spaceV3: halfway between V2 and V4V4: left 5th intercostal space, mid-clavicular lineV5: horizontal to V4, anterior axillary lineV6: horizontal to V5, mid-axillary line
Mean electrical axis (mean cardiac vector)
Experimental objectives
Record ECG from lead 1 and 3 Lying down, sitting up and breathing deeply
while sitting
Review the ECGs for lead 2
Direction of QRS complex vs. the direction of the lead axis
Estimate the mean electrical axis of the QRS complex