Transatrial balloon technique for activation mapping during operations for recurrent ventricular tachycardia

Results of operations for recurrent ventricular tachycardia have improved since methods of mappig that allow a directed approach to the problem have been developed. With standard operative techniques (ventriculotomy and introduction of a hand-held probe or multiple electrode array), it has not always been possible to obtain satisfactory endocardial activation maps during the tachycardia. We have recently developed a new transatrial balloon approach that has greatly facilitated intraoperative mapping. This paper describes our total exprience with the new approach and draws attention to details of the cardiopulmonary bypass technique and the surgical approach needed for safe balloon insertion across the mitral valve. We describe how correlation between position of target electrodes on the balloon and the internal geometry of the heart is achieved and discuss the choice and application of appropriate ablation techniques. In our series of 37 consecutive patients, 35% had a grade IV ventricle (ejection fraction < 20%), 32% had a previous posterior infarct, 51% did not have a resectable aneurysm, and 54% had been receiving amiodarone within 1 month of the operation. These factors have been associated with poor operative results in other series. With the transatrial balloon technique, we were able to induce and map ventricular tachycardia in 100% of patients (average 2.6 ± 1.3 morphologies per patient). Using a variety of ablation techniques (endocardial excision, cryoablation, or ballooon electric shock ablation), we have achieved surgical control of the arrhythmias in 84% of patients with an operative mortality rate of 14%. We recommend transatrial balloon mapping as the procedure of choice for intraoperative identification of arrhythmogenic foci in patients with recurrent ventricular tachycardia.