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Updated: Oct 28, 2025

Author Spotlight: Investigating HR-Dependent Cardiac Function in Mouse Models Through a Novel Atrial-Pacing Approach
Published on: July 21, 2023
Life and death saddles in the heart
Zhaoyang Zhang1, Zhilin Qu1,2
1Department of Medicine, University of California, Los Angeles, California 90095, USA.
Abstract:
Saddle points are responsible for threshold phenomena of many biological systems. In the heart, saddle points determine the normal excitability and conduction, but are also responsible for certain abnormal action potential behaviors associated with lethal arrhythmias. We investigate the dynamical mechanisms for the genesis of lethal extra heartbeats in heterogeneous cardiac tissue under two diseased conditions. For both conditions, the lethal events occur when the system is close to the saddle point, implying the pivotal role of the saddle point in cardiac arrhythmogenesis.
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