How does ischemia influence heart rhythm during arrhythmias?

Ischemia, which refers to a reduced blood flow to the heart muscle, significantly influences heart rhythm by altering electrical conduction, ultimately leading to arrhythmias. When ischemia occurs, the affected myocardial cells experience a lack of oxygen and nutrients, which disrupts their ability to generate electrical impulses effectively. This disruption can create areas of increased excitability and decreased conduction velocity, leading to a higher risk of abnormal rhythms.

During ischemia, the ion channels in cardiac cells become impaired, leading to changes in the resting membrane potential and action potential duration. This can result in abnormal conduction pathways or reentrant circuits, which are common mechanisms that initiate arrhythmias. The alteration in conduction can also create conditions that allow for ectopic foci to emerge, further contributing to arrhythmogenic potential. Consequently, the overall impact of ischemia on heart rhythm is characterized by an increased likelihood of developing arrhythmias due to these dysfunctional electrical properties.