a 62-year - old man with palpitations was referred to our center for catheter ablation due to a paroxysmal atrial tachycardia ( at ) . during the first procedure , the pulmonary veins ( pvs ) the pv isolation ( pvi ) using the cryoballoon was difficult , especially for the left inferior pv ( lipv ) due to the adjacent inferior branch of the left superior pv ( lspv ) ( fig . the at was considered to be a peri - mitral atrial flutter by an entrainment study around the mitral annulus . however , a mitral isthmus ablation was not attempted because it was a non - clinical peri - mitral flutter . six months after the first procedure , a paroxysmal at recurred . delayed enhancement magnetic resonance imaging ( de - mri ) demonstrated an eccentric cryothermal lesion around the lipv . in addition , an extensive cryothermal lesion was located on the anterior wall of the lipv and a lesion gap was seen on the posterior wall of the lipv ( figs . 1b and c , and 2 ) . a pv - left atrium ( la ) re - conduction several radiofrequency ( rf ) applications at the cryothermal lesion gap could achieve pv - la conduction block . the at was considered to be a peri - mitral atrial flutter because the p - wave morphology was similar to that of the induced peri - mitral atrial flutter during the first procedure . however , no at could be induced by any programed stimulation during an isoproterenol infusion . detailed mapping at the mitral isthmus was performed during sinus rhythm , and a voltage map demonstrated a localized low voltage area on the anterior wall of the lipv where a delayed dull potential was recorded during left atrial appendage pacing ( figs . a single sharp potential was recorded between the extensive cryothermal lesion and mitral annulus ( fig . 2 ) . a single rf application at that site could achieve a significant conduction delay across the mitral isthmus . a complete bidirectional block was achieved after 3 additional rf applications near the mitral annulus . there has been no recurrence of at as of the last available follow - up ( 9 months ) . a multi - center study reported that de - mri could visualize rf lesions as well as a preexisting atrial fibrosis after af ablation . we also reported that the exact localization of rf lesions could be recognized by de - mri fused with magnetic resonance angiography . the lesion gap assessed by de - mri is reported to correspond to the electrical re - conduction sites verified by an ablation catheter or ring catheter . furthermore , we reported that the dense enhancement sites and patchy sites assessed by de - mri could correspond to an arrhythmogenic substrate . however , it has not been well discussed whether the cryothermal lesions after cryoballoon ablation can be visualized by de - mri . in this case , de - mri could demonstrate a small but high signal intensity area located on the anterior wall near the lipv . 1b shows a relatively low signal intensity area located between the high signal intensity areas . a delayed enhancement area was defined as the area with a signal intensity of > 3  sd , to avoid an overestimation of non - specific atrial fibrosis . considering the small area and high threshold of the high intensity area , this patchy scar was induced by a cryothermal lesion , not by any preexisting atrial fibrosis . furthermore , the cryothermal lesions assessed by de - mri were characterized as follows : both the width and signal intensity of the lesion were likely to be greater than that after a conventional rf ablation . in previous reports , it was believed that the width and signal intensity might be associated with the durability of the cryothermal lesion and an increased creatinine phosphokinase level . in cryoballoon ablation , it is reported that the cryothermal lesion extends to the antral region around the pvs . however , the cryothermal lesions around the pvs depend on the pv and la anatomy . if the longitudinal axis of the pv and the cryoballoon catheter are coaxial , the pvi could be achieved easily and an extensive cryothermal lesion could be achieved concentrically around the pv . if not , the pvi may be difficult and the cryothermal lesion may be smaller and eccentric . the accuracy of de - mri in detecting cryothermal lesion gaps after cryoballoon ablation may be reliable .
the impact of a cryoballoon ablation is reported to be similar to that of a radiofrequency ( rf ) ablation in patients with atrial fibrillation . 
 delayed enhancement magnetic resonance imaging ( de - mri ) could visualize the scar region induced by the cryoballoon ablation as well as rf ablation . 
 cryoballoon ablation could induce extensive scar lesions around the pvs . 
 however , the distribution of the scar lesions after the cryoballoon ablation has not been well discussed . 
 we , herein , described a case with an eccentric scar distribution after cryoballoon ablation .