【摘要】 在离体兔心窦房结部位的心外膜面记录到窦房结电位。它在相应的心电图P波前出现,窦房传导时间为8～30ms,舒张期斜坡之dv/dt为0.16～0.64mv/sec,向上斜坡之dv/dt为5.1～25.1mv/sec,“4相”向“0相”过渡匀滑,波幅为230～790μv给予河豚毒素后可使叠加在其上的A波消失,因而图形与窦房结起搏细胞的动作电位相似,并可在给予异博定后立即消失。证实此电活动是窦房结区以起搏细胞为主的跨膜电位变化在心外膜面的反映。更多还原

【Abstract】 The sinus node potential (SNP) wasrecorded on the epicardial surface overthe sinus node of the isolated rabbitheart. It preceded the corresponding Pwave of ECG. The sino-atrial conduc-tion time was 8 to 30 msec. The diasto-lic slope was 0.6 to 0.64 mv/sec. The upstroke slope was 5.1 to 25.1 mv/sec.During transition from phase 4 to phase0 the slope of the Potential increasedsmoothly. The magnitude was 230 to790/uv. After tetrodotoxin abolishedthe A wave which overlapped the SNP,the pre-P wave looked theroafter similarto the trans-membrance action potential(TAP) of the sinus node pacemakercell. When verapmil was rendered theSNP disappeared. These results suggestthat the pre-P wave is mainly due to areflection of the TAP of the sinus nodepacemaker cell on the epicardial surface更多还原