Extrinsic 4449-1

{
  "heartbeat": {
    "blockNumber": 4447,
    "sessionIndex": 74,
    "validatorsLen": 4,
    "authorityIndex": 1
  },
  "signature": "0x3425cbc43f4c9d068024d6f7f01a3785d2aa5621d4efdef028897578a777da00f3aa83135f86edc424232dddfe1e8f6505dd97fb56cebb383c8c83fb58f41288"
}