@misc{indiciae680aba593c79,
  title = {Letter: Second degree A-V block.},
  author = {N el-Sherif and B J Scherlag and R Lazzara},
  year = {1974},
  doi = {10.1016/0002-9149(74)90721-8},
  url = {https://pubmed.ncbi.nlm.nih.gov/4432823/},
  note = {Source identifier: 4432823}
}