Endresen K, Amlie J P, Forfang K, Simonsen S, Jensen O
Medical Department B, Rikshospitalet, Oslo, Norway.
Cardiovasc Res. 1987 Sep;21(9):696-702. doi: 10.1093/cvr/21.9.696.
Monophasic action potentials were recorded in the outflow tract of the right ventricle in patients with coronary artery disease during ventricular pacing at different basic cycle lengths and programmed stimulation. During continuous pacing (basic cycle length 600 ms) the time for 90% repolarisation (MAP90) and the QTa interval decreased exponentially during the first 1.5-2 min of pacing to 90% of control values. The reproducibility of the monophasic action potential signals and the ventricular effective refractory period were assessed as good when studied after repetitive trains of 8 beats for more than 1.5 min. The reproducibility of conduction, however, was less good. Electrical restitution of MAP90 duration of the premature beats determined at three different basic cycle lengths was different from that in single muscle preparations. The curves showed two phases with unchanged MAP90 durations despite longer coupling intervals. The first phase was close to the ventricular effective refractory period, probably because subnormal conduction left the diastolic interval constant for the earliest premature beats. This indicates that subnormal conduction may influence the premature dispersion of repolarisation.
在冠心病患者右心室流出道进行不同基础周期长度的心室起搏和程控刺激时，记录单相动作电位。在持续起搏（基础周期长度600毫秒）期间，起搏最初1.5 - 2分钟内，90%复极化时间（MAP90）和QTa间期呈指数下降至对照值的90%。当在超过1.5分钟的8次搏动重复序列后进行研究时，单相动作电位信号和心室有效不应期的可重复性评估为良好。然而，传导的可重复性则不太好。在三个不同基础周期长度下测定的早搏MAP90持续时间的电恢复与单个肌肉标本中的情况不同。曲线显示出两个阶段，尽管耦合间期延长，但MAP90持续时间不变。第一阶段接近心室有效不应期，可能是因为传导减慢使最早早搏的舒张期间期保持恒定。这表明传导减慢可能影响复极化的早搏离散度。
