Carson D L, Cardinal R, Savard P, Vermeulen M
Cardiovasc Res. 1986 Jul;20(7):521-7. doi: 10.1093/cvr/20.7.521.
The relation between electrical alternans recorded in acutely ischaemic myocardium, ventricular arrhythmias, and changes in the activation sequence was studied. Sixty three unipolar electrograms, simultaneously recorded from the epicardial surface of the in situ porcine heart during 6 min periods of coronary occlusion, were converted to a digital format and analysed by computer. The time integrals of the electrograms during their QRS complex, ST segment, and T wave were measured. Unipolar waveform alternation was then quantified by subtracting the values obtained for two consecutive beats showing alternans. The spatial distribution of unipolar waveform alternation was illustrated by isoarea difference maps. Isochronal maps of the local excitation detected on each electrogram were constructed. Of 52 occlusions in 27 preparations, unipolar waveform alternation was detected in 42 and was promptly followed by ventricular arrhythmias in 37. The magnitude of unipolar waveform alternation increased from the margin to the inner portion of the ischaemic zone but its correlation with activation delay was poor, and there was no change in the activation sequence. These results suggest that beat to beat alternation of the unipolar waveform is related to changes in the action potential configuration rather than to changes in the activation sequence. Furthermore, unipolar waveform alternation appears to be associated with the development of early post-occlusion ventricular arrhythmias.
研究了急性缺血心肌中记录的电交替、室性心律失常与激动顺序变化之间的关系。在猪原位心脏冠状动脉闭塞6分钟期间，从心外膜表面同时记录63个单极电图，并转换为数字格式，由计算机进行分析。测量电图在其QRS波群、ST段和T波期间的时间积分。然后通过减去显示交替现象的两个连续心搏获得的值来量化单极波形交替。单极波形交替的空间分布通过等面积差图来说明。构建了在每个电图上检测到的局部激动的等时图。在27个标本的52次闭塞中，42次检测到单极波形交替，其中37次随后迅速出现室性心律失常。单极波形交替的幅度从缺血区边缘向内部增加，但其与激动延迟的相关性较差，且激动顺序无变化。这些结果表明，单极波形的逐搏交替与动作电位形态的变化有关，而不是与激动顺序的变化有关。此外，单极波形交替似乎与闭塞后早期室性心律失常的发生有关。
