Homcy C J, Lorell B, Yurchak P M
Circulation. 1979 Sep;60(3):711-4. doi: 10.1161/01.cir.60.3.711.
The mechanism of atrial flutter is controversial. A 76-year-old woman with rheumatic heart disease was referred to our clinic with an unusual rhythm disturbance which initially appeared to be classic atrial flutter at a rate of 300 beats/min. Later tracings, however, demonstrated a rate exactly one-half that of the earlier ECGs, with an identical p-wave morphology and vector. This latter rhythm also behaved in a manner expected for a flutter mechanism in that both spontaneously and with carotid pressure high-degree atrioventricular block occurred without alteration of the underlying atrial mechanism. Finally, the two rates interchanged spontaneously over several days without any significant interval changes in medical therapy. These findings were initially explained as probable digoxin toxicity. The underlying mechanism, however, was more likely atrial flutter with exit block and in this patient may have represented another facet of her sick sinus syndrome. This unusual phenomenon is discussed in terms of previous reports and possible implications for the mechanism of atrial flutter.
心房扑动的机制存在争议。一名患有风湿性心脏病的76岁女性因一种不寻常的节律紊乱被转诊至我们的诊所，该紊乱最初表现为典型的心房扑动，心率为300次/分钟。然而，后来的心电图显示心率恰好是早期心电图的一半，P波形态和向量相同。后一种节律也表现出符合扑动机制的特点，即无论是自发还是在颈动脉按压时都会出现高度房室传导阻滞，而基础心房机制未改变。最后，在几天内两种心率自发互换，药物治疗期间间隔无明显变化。这些发现最初被解释为可能是地高辛中毒。然而，潜在机制更可能是伴有传出阻滞的心房扑动，在该患者中可能代表了其病态窦房结综合征的另一个方面。根据先前的报告讨论了这种不寻常的现象以及对心房扑动机制的可能影响。
