Polymorphic reentrant ventricular tachycardia in the isolated rabbit heart studied by high-density mapping

Article

关键词: TORSADES-DE-POINTES;    FUNCTIONAL REENTRY;    QT INTERVAL;    MECHANISM;    TERMINATION;    MYOCARDIUM;    ARRHYTHMIAS;    EXCITATION;    ACTIVATION;    PERIOD;   

DOI  :  10.1161/01.CIR.0000019407.35848.AF

来源: SCIE

【 摘 要 】

Background-The role of dispersion of refractoriness and reentry for the genesis of polymorphic ventricular tachycardia (VT) has recently become emphasized. We investigated the mechanisms of polymorphic arrhythmias in a 2D preparation confining an area of prolonged refractoriness. Methods and Results-In 16 Langendorff-perfused rabbit hearts, a sheet of left ventricular epicardium was obtained by a cryoprocedure. Enhanced spatial heterogeneity in a refractory period was created by cooling a central region (diameter= 12 mm). This markedly prolonged the refractory period (by 36+/-14 ms) inside but only slightly prolonged it (by 5 +/- 11 ms) outside the cooled area (n = 6). During a control procedure, programmed stimulation with up to 3 premature stimuli induced an episode of monomorphic VT in only 1 of 10 hearts. During regional cooling, episodes of polymorphic VT with a maximum duration of 35 seconds could be induced in all hearts. High-resolution mapping (229 electrodes) of epicardial activation revealed that polymorphic VT was caused by a functional reentrant circuit located partially within the region of prolonged refractoriness. The reentrant wavefront was continuously shifting along the border of the cooled region, resulting in beat-to-beat changes in the excitation pattern. Spontaneous termination of polymorphic VT occurred either by a shift of the reentrant circuit outside the cooled region or by a block in the central common pathway during figure-of-8 reentry in the region of prolonged refractoriness. Conclusions-A shifting functional reentrant circuit was the underlying mechanism of polymorphic VT in a substrate of enhanced spatial heterogeneity of refractoriness.

【 授权许可】

Free