Introduction: Modified substrate of ventricular myo-cardium may express areas of slow conduction and fractionated electrograms. When performed, pace mapping at this area may express a surface ECG QRS morphology similar with clinical ventricular tachycar-dia and multiple exit morphologies. Pace-mapping at this sites ca also induce the targeted ventricular ta-chycardia.
Methods: Seven patients with structural heart disease (2p with non compaction cardiomyopathy, 1 patient with arrhythmogenic right ventricular displasia and 4 patients with postinfarction myocardial scar) hospita-lised in our center in the past 2 years were evaluated by elctrophysiological study during conventional proce-dures. The induction of the clinical tachycardia during pace-mapping at the target point or best match pacing, assessment of fractionated electrograms and multiple exit morphologies during pacing were targeted. Radi-ofrequency catheter ablation was performed in each case.
Results: In 4 patients to whom all three criteria have been met, the ventricular tachycardia was non-induc-tible after ablation. In 3 patients (1p with non compac-tion cardiomyopathy and 2 patients with large postin-farction scars) the recurrence of multiple forms of ven-tricular tachycardia was observed.
Conclusions: T he fractionated electrograms that ex-hibit multiple exit sites during pace mapping may be critical sites for reentry and constitute good targets for ablation in patients with structural heart disease or post myocardial infarction scar. When the clinical ven-tricular tachycardia can be induced by pace-mapping from the specific site can be a marker of arrhythmia freedom after ablation.