it is defined as the presence of an akinetic or dyskinetic structure with a wide connection to the left ventricle , which is normal in size and function . patients with lva are frequently asymptomatic but congestive heart failure , tachyarrhythmias and systemic embolisation may develop . even sudden death has been observed in lva patients and may be related to rupture of the lva [ 3 , 4 ] . in a group of 108 patients with either lva or diverticulum , who were followed during a median period of 50 months , vts occurred in only ten patients . . reported on cardiac mapping prior to ablation in four lva patients with recurrent exercise - induced syncope attributable to sustained fast monomorphic vt . the aneurysm was located in the inferolateral part of the left ventricle in all patients . mapping during sinus rhythm revealed abnormal signals ( fractionated or late potentials ) on the epicardium but not on the endocardium . in one patient with a stable vt , epicardial mapping showed a macrore - entrant vt with a focal pattern of activation at the endocardial surface . hence , our case is the first lva patient in whom ( 1 ) endocardial mapping revealed extensive conduction abnormalities ( low voltage , double and fractionated potentials ) , and ( 2 ) successful ablation was accomplished at the endocardial surface . our patient had a dilated left ventricle and depressed ejection fractionindicating a more advanced stage of lva compared with the patients in the study by ouyang et al . . the underlying mechanism of the vt is most likely a microre - entry circuit at the endocardial surface . ventricular tachycardia after cardiac surgery for lvas can be treated by endocardial catheter ablation at the endocardial surface of the left ventricle . extensive local conduction abnormalities are recorded within the endocardial surface of the aneurysm which may form the substrate of the ventricular tachycardia .
we present a patient with a congenital left ventricular aneurysm who visited our outpatient clinic for a routine check - up and , during this visit , lost consciousness due to sustained ventricular tachycardia . in our patient , endocardial mapping revealed extensive conduction abnormalities , and successful ablation was accomplished at the endocardial surface .