心電圖分析ppt課件-免費(fèi)閱讀
【正文】 QRS≥。以 Ⅱ 、 Ⅲ 、 aVF明顯。 I。 形式：心電向量圖 心電圖 其它：如動(dòng)態(tài)心電（ Holter) 心電圖運(yùn)動(dòng)負(fù)荷試驗(yàn) 標(biāo)準(zhǔn)十二導(dǎo)聯(lián)心電圖 心電產(chǎn)生原理 靜息電位：心肌細(xì)胞極化狀態(tài) 膜內(nèi)電位 － 90mV 細(xì)胞內(nèi) K+↑ 細(xì)胞外 Na+ ↑ 膜通透性 K+ ↑ Na+ ↓ What makes the “squiggles”? Heart muscle is made of long thin heart muscle cells What makes the “squiggles”? Na Na Na Ca Ca Ca K K K K K Potassium Na Sodium Ca Calcium Negative Charge Positive Charge Cell membrane Heart Muscle Cell The membrane pumps sodium ions into the cells at a faster rate than it pumps sodium and calcium ions out. This results in a higher concentration of positive ions outside the cell. The cell is POLARIZED. Depolarization and Repolarization _ _ _ _ _ _ _ _ _ _ _ _ + + + + + + + + + + + + Repolarization and Relaxation Depolarization and Repolarization _ _ _ _ _ _ _ _ _ _ _ _ + + + + + + + + + + + + Depolarization and contraction When a heart muscle cell depolarizes, the rapid flow of ions across the membrane causes a wave of electrical current which causes the muscle to contract. This current called the depolarization wave spreads rapidly through the heart. Depolarization and Repolarization _ _ _ _ _ _ _ _ _ _ _ _ + + + + + + + + + + + + Repolarization and Relaxation 除極、復(fù)極形成動(dòng)作電位 ? 除極：快 Na+通道開(kāi)放 Na+內(nèi)流 ? 復(fù)極：快速?gòu)?fù)極相 Cl內(nèi)流 緩慢復(fù)極相 K+外流 Ca2+內(nèi)流 快速末期復(fù)極相 K+外流 +30mV 0 30mV 60mV 90mV 0 1 2 3 4 心電圖為心電向量環(huán) 兩次投影結(jié)果 ? 電偶學(xué)說(shuō)：電穴、電源形成電偶 除極：電穴 → 電源 心內(nèi)膜 → 心外膜 復(fù)極：電源 → 電穴 心外膜 → 心內(nèi)膜 ? 心電向量、綜合心電向量：有大小
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