{
  "abstract": "Background Rotors are thought to be critical in sustaining ventricular fibrillation (VF). Myocardial fibrosis may promote and stabilise rotational activity. Yet, due to ethical, practical and technical challenges of VF mapping, little evidence from whole heart in-vivo studies is available linking rotational activity in sustained VF to myocardial scarObjective Combine global epicardial contact mapping during long duration VF with high-resolution MRI imaging data to characterise rotational activity and its spatial correlation to post-infarct scar in an in-vivo porcine model.Methodology An infarct model was created in danish landrace pigs via mid-LAD balloon-occlusion followed by 5–6 weeks recovery for infarct maturation. Placement of an epicardial 256-electrode sock was followed by VT induction with degeneration to VF. VF traces were sampled at 1kHz & low pass filtered at 40Hz. Epicardial phase was calculated at each electrode with Hilbert transform. Signals were linearly interpolated from the electrodes onto a fine regular grid. Persistent rotors were defined as continuous PS (tracked at a resolution of 1ms) with a lifetime > 1000ms. Number, lifetime, co-existence, location and mobility for all rotors were assessed. Mobility was evaluated by identifying the median coordinates of each rotor and if the rotor was >50% of its lifetime within ±3.6mm of the median coordinates, it was considered stationary, if <50% it was classified as mobile.Post-VF recording, hearts were explanted, sock electrodes tagged with MRI markers & ex-vivo DE-MRIs acquired for scar delineation. DE-MRI models were reconstructed and co-registered based on the MRI markers. Sock electrodes were allocated to core-scar, border zone or normal myocardium; rotors were assigned to the spatially closest electrode based on their median coordinates.Results VF was recorded for 26±3.5min in 8 pigs with established LAD infarct. On average 88 (IQR 118) persistent epicardial rotors were detected per pig. 52.8% were spatially associated with the scar (13.6%) and/or its border zone (39.2%). In the late stages of VF (>10min) the proportion of rotors associated with scar increased to 59.8%. Scar-related persistent rotors trended to be more often stationary than non-scar rotors (64 vs 59.4%, p 0.091), but there was no significant difference in rotor lifetime (1192±353 vs 1229±375ms, p ns). Co-existence of persistent rotors occurred in 35.4% of all epochs with on average 2 (IQR3) rotors overlapping by 864±507ms. In all pigs repeated periods with no persistent rotational activity were recorded indicating that other processes also play a role in maintaining VF.Conclusion This is the first study employing both high resolution mapping and imaging in a large in vivo animal model linking structural alterations directly to long duration VF dynamics. Persistent rotational activity is an important mechanism in sustained VF and preferentially manifests around the border zone of post infarct scar, particularly in the later stages of VF.",
  "authors": [
    {
      "affiliations": [
        "Institute for Cardiovascular Science, University College London, UK",
        "St Bartholomew s Hospital, London, UK"
      ],
      "name": "Johanna B Tonko"
    },
    {
      "affiliations": [
        "University of Copenhagen, Denmark"
      ],
      "name": "Stefan Sattler"
    },
    {
      "affiliations": [
        "University of Copenhagen, Denmark"
      ],
      "name": "Sarah Dalgas-Nissen"
    },
    {
      "affiliations": [
        "University of Copenhagen, Denmark"
      ],
      "name": "Kezia Jerltorp"
    },
    {
      "affiliations": [
        "University of Copenhagen, Denmark"
      ],
      "name": "Laura Friderichsen"
    },
    {
      "affiliations": [
        "University of Copenhagen, Denmark"
      ],
      "name": "Johannes Castelein"
    },
    {
      "affiliations": [
        "University of Copenhagen, Denmark"
      ],
      "name": "Arnela Saljic"
    },
    {
      "affiliations": [
        "University of Copenhagen, Denmark"
      ],
      "name": "Dominik Linz"
    },
    {
      "affiliations": [
        "University of Copenhagen, Denmark"
      ],
      "name": "Thomas Jespersen"
    },
    {
      "affiliations": [
        "St Bartholomew s Hospital, London, UK"
      ],
      "name": "Anthony Chow"
    },
    {
      "affiliations": [
        "University of Sheffield, Sheffield, UK"
      ],
      "name": "Richard Clayton"
    },
    {
      "affiliations": [
        "Institute for Cardiovascular Science, University College London, UK",
        "St Bartholomew s Hospital, London, UK"
      ],
      "name": "Pier Lambiase"
    }
  ],
  "title": "4-030 The relationship of rotational activity during long duration ventricular fibrillation to post-infarct scar: a combined MRI and epicardial high density mapping study",
  "uid": "f50092b9-cfdb-59ec-85ab-e72df7ebb8ef"
}