Extrinsic 18456-1

{
  "heartbeat": {
    "blockNumber": 18454,
    "sessionIndex": 307,
    "validatorsLen": 4,
    "authorityIndex": 2
  },
  "signature": "0xac3db142d81be584495a63292532882c7ac904cd5ddd164f1aaee8783674c11da77cfed53f66b4cfdb6bc1a9f31760936c3d6a77216651d3768888359353b482"
}