Key result
Local cooling of the mid-to-late diastolic portions of re-entry loops terminated 8 of 8 induced ventricular tachycardias in dogs, compared to 5 of 8 when cooling the site of origin.
Why the study?
Does the site of cryo-termination correlate with the site of origin in ventricular tachycardia?
Does the site of cryo-termination correlate with the site of origin in ventricular tachycardia?
Answers are grounded in this paper and cite their sources.
In a canine model of MI-induced VT, the site of cryo-termination for macrore-entrant VT is dissociated from the site of origin, with cooling of mid-to-late diastolic portions being more effective for termination.
We performed conventional electrogram mapping and cryomapping in dogs with one-week-old experimentally-induced myocardial infarctions and programmed stimulation-induced sustained ventricular tachycardias to assess whether there is a correlation between the "site of origin" and site of cryo-termination of ventricular tachycardia (VT). Electrogram maps showed that 4 of 8 induced sustained VTs were due to macro- and 4 of 8 to microre-entry. Local cooling of the site of origin terminated 4 of 4 microre-entrant VTs, but only 1 of 4 macrore-entrant VTs. In the other 3 macrore-entrant VTs, the sites of cryo-termination were 2, 2.5, and 4 cm distant from the sites of origin. In contrast, cooling of the mid-to-late diastolic portions of the re-entry loops terminated all 8 VTs. These data demonstrate a dissociation of the site of origin from the site of cryo-termination of macrore-entrant VT.
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Gessman et al. (1983) studied Ventricular tachycardia. Local cooling (cryomapping) vs. Cooling of the site of origin vs mid-to-late diastolic portions of re-entry loops was evaluated on Termination of ventricular tachycardia. Local cooling of the mid-to-late diastolic portions of re-entry loops terminated 8 of 8 induced ventricular tachycardias in dogs, compared to 5 of 8 when cooling the site of origin.
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