心臟病中「心因性猝死(Sudden Cardiac Death, SCD)」就佔了半數。其中又有80\% 是由心室引起的心律不整。心律不整的成因除了組織損傷外，心臟中的非線性動力系統也是主因之一。一般相信心臟由規律進入到不規律狀態的過程中會經過倍週期狀態。因此如何將倍週期狀態中的心臟拉回週期性的規律心跳，甚至是早一步阻止其進入倍週期的方法成為預防心律不整的重要課題，亦是本研究的主要目的。本研究使用了一個新的控制方法。可以影響心臟動力系統原有的分岔點(Bifurcation point)，使倍週期心跳恢復為單週期。此外，控制過程中所形成的吸引子形狀也可以作為判斷系統狀態的依據。

About 50\% of all cardiovascular deaths are sudden cardiac deaths and about 80\% of these are caused by ventricular tachyarrhythmia. The cause of arrhythmias is not only because of physical damage in cardiac tissues but can also originate from the nonlinear dynamics of the heart. It is believed that period doubling in the beating of a heart is a precursor of arrhythmias.
The goal here is to develop a method for the suppression of period doubling. This study uses a new control method, known as T+T-, to affect the bifurcation point in a dynamical system. The T+T- method can suppress period doubling in the beating of the heart. Furthermore, the shape of the attractor constructed from the beating of the heart under the T+T- control can also provide useful information about the dynamical state of the heart.

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