The electrocardiogram in normal pregnancy.

@article{Carruth1981TheEI,
  title={The electrocardiogram in normal pregnancy.},
  author={J E Carruth and S B Mivis and Donna R. Brogan and Nanette K Wenger},
  journal={American heart journal},
  year={1981},
  volume={102 6 Pt 1},
  pages={1075-8}
}