When the heart beats, an electrical signal passes from the top of the heart, near the atria (upper chambers), down through the ventricles (lower chambers), and the chambers contract in that order.

当心脏跳动时，一个电子信号就会从心脏的顶部传到一个心腔（位于上部），然后是位于下部的心腔，当它收缩时，也是按照这样的顺序。

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Normally the sinoatrial node generates regular electrical pulses that spread across the Chambers of the heart, causing the cells to contract in synchrony.

正常情况下，窦房结产生规律的电脉冲，传入各心房，再带动细胞同步收缩。

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By inserting electrodes into one or more of the Chambers of the heart, via a large vein, it is possible to mimic its function by applying small electrical shocks at regular intervals.

把电极通入一个或多个心房或心室，并使导入一条大静脉，就可以通过有规律的小幅电击模拟窦房结发挥作用。

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The upper chambers of the heart quiver or beat too fast or too slow.

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Lotem said that during the heart catheterization procedure doctors would use a thin plastic tube to insert an "umbrella-like" device that will seal the hole between the two upper chambers of the heart.

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They are designed to help the pumping action of the left ventricle - one of the four chambers that make up the heart.

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