Reconstruction of the patterns of gene expression in the developing mouse heart reveals an architectural arrangement that facilitates the understanding of atrial malformations and arrhythmias

Circ Res. 2004 Dec 10;95(12):1207-15. doi: 10.1161/01.RES.0000150852.04747.e1. Epub 2004 Nov 18.


Firm knowledge about the formation of the atrial components and of the variations seen in congenital cardiac malformations and abnormal atrial rhythms is fundamental to our understanding of the normal structure of the definitive atrial chambers. The atrial region is relatively inaccessible and has continued to be the source of disagreement. Seeking to resolve these controversies, we made three-dimensional reconstructions of the myocardial components of the developing atrium, identifying domains on the basis of differential expression of myocardial markers, connexin40, and natriuretic precursor peptide A. These reconstructions, made from serial sections of mouse embryos, show that from the outset of atrial development, the systemic and pulmonary veins are directly connected to the atrium. Relative to the systemic junctions, however, the pulmonary venous junction appears later. Our experience shows that three-dimensional reconstructions have three advantages. First, they provide clear access to the combined morphological and molecular data, allowing clarification and verification of morphogenetic concepts for nonmorphological experts and setting the scene for further discussion. Second, they demonstrate that, from the outset, the myocardium surrounding the pulmonary veins is distinct from that clothing the systemic venoatrial junctions. Third, they reveal an anatomical and molecular continuity between the entrance of the systemic venous tributaries, the internodal atrial myocardium, and the atrioventricular region. All these regions are derived from primary myocardium, providing a molecular basis for the observed nonrandom distribution of focal right atrial tachycardias.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Atrial Appendage / embryology
  • Atrial Appendage / metabolism
  • Atrial Natriuretic Factor
  • Connexins / analysis
  • Connexins / biosynthesis
  • Connexins / genetics*
  • Fetal Heart / anatomy & histology
  • Fetal Heart / metabolism*
  • Gene Expression Regulation, Developmental*
  • Gestational Age
  • Heart Atria / embryology*
  • Heart Atria / metabolism
  • Heart Conduction System / embryology*
  • Mesoderm / ultrastructure
  • Mice
  • Models, Anatomic*
  • Myocardium / chemistry
  • Myocardium / cytology
  • Myocardium / metabolism
  • Natriuretic Peptide, C-Type / analysis
  • Natriuretic Peptide, C-Type / biosynthesis
  • Natriuretic Peptide, C-Type / genetics*
  • Protein Precursors / analysis
  • Protein Precursors / biosynthesis
  • Protein Precursors / genetics*
  • Pulmonary Veins / embryology*
  • Pulmonary Veins / metabolism
  • Staining and Labeling
  • Tachycardia, Ectopic Atrial / embryology
  • Tachycardia, Ectopic Atrial / etiology*
  • Tachycardia, Ectopic Atrial / pathology


  • Connexins
  • Nppa protein, mouse
  • Protein Precursors
  • connexin 40
  • Natriuretic Peptide, C-Type
  • Atrial Natriuretic Factor