Creation of a left ventricular cryolesion in dogs acutely induced frequent ventricular premature beats in 100% (6/6) and ventricular tachycardia in 83% (5/6), which largely resolved after 1 week.
Absolute Event Rate: 100% vs 0%
The acute and chronic electrophysiological effects of a cryolesion produced in the left ventricle were studied in six dogs. All dogs had frequent ventricular premature beats (VPB) and five of six dogs had ventricular tachycardia during the first 4 days after the cryolesion; only one of the six dogs continued to have VPBs after 1 week, and this dog had identical VPBs before the creation of the cryolesion. Neither control dog had VPBs. Two additional dogs underwent epicardial and transmural mapping studies immediately after production of a cryolesion. VPBs in these animals were shown to originate at the border of the cryolesion. Epicardial activation sequence during normal sinus rhythm was not altered by the chronic cryolesion. The border zone of the chronic cryolesion was sharply demarcated with normal potentials recorded outside of the lesion and "extrinsic" potentials recorded within.
Klein et al. (Thu,) conducted a other in Myocardial cryolesion (n=10). Cryosurgery (cryolesion in the left ventricle) vs. Control (no cryolesion) was evaluated on Ventricular premature beats (VPB) during the first 4 days. Creation of a left ventricular cryolesion in dogs acutely induced frequent ventricular premature beats in 100% (6/6) and ventricular tachycardia in 83% (5/6), which largely resolved after 1 week.