Developmental aspects of cardiac arrhythmias

Abstract

The rhythmic and synchronized contraction of atria and ventricles is essential for efficient pumping of blood throughout the body. This process relies on the proper generation and conduction of the cardiac electrical impulse. Electrophysiological properties differ in various regions of the heart, revealing intrinsic heterogeneities rooted, at least in part, in regional differences in expression of ion channel and gap junction subunit genes. A causal relation between transcription factors and such regionalized gene expression has been established. Abnormal cardiac electrical function and arrhythmias in the postnatal heart may stem from a developmental changes in gene regulation. Genome-wide association studies have provided strong evidence that common genetic variation at developmental gene loci modulates electrocardiographic indices of conduction and repolarization and susceptibility to arrhythmia. Functional aspects are illustrated by description of selected prenatally occurring arrhythmias and their possible mechanisms. We also discuss recent findings and provide background insight into these complex mechanisms.