Role of contact and noncontact mapping in the curative ablation of tachyarrhythmias

Non-fluoroscopic catheter-based mapping systems in cardiac electrophysiology--from approved clinical indications to novel research usage

BACKGROUND

During 20 years of development of catheter-based technologies in the management of cardiac arrhythmias, electrophysiological mapping/ablation systems have evolved from single-plane fluoroscopic mapping to three-dimensional (3-D) non-fluoroscopic computer-based mapping systems.

METHODS

Based on magnetic technology, the electro-anatomic CARTO mapping system can accurately correlate local electrograms with recording sites, by which the system can reconstruct 3-D maps with colour-coded electrophysiological information superimposed on the anatomy. Whereas the CARTO system is primarily designed for studying cardiac activation and not repolarisation, the system has been widely used in the diagnosis and ablation of cardiac arrhythmias and in the research of basic arrhythmic mechanisms.

RESULTS

In order to study cardiac repolarisation in vivo, an innovative method, the monophasic action potential (MAP) mapping technique, which integrates MAP recording with electroanatomical mapping, has recently been developed in our centre. Using the MAP technique, global sequence and dispersion of atrial/ventricular repolarisation have been evaluated in vivo in both experimental and clinical settings.

CONCLUSION

The innovative MAP technique provides unique research opportunities for in vivo studies of basic electrophysiological mechanisms.

Radiofrequency Ablation of the Ventricular Tachycardia with Arrhythmogenic Right Ventricular Cardiomyopathy Using Non-contact Mapping

BACKGROUND

Intracardiac non-contact mapping provides a rapid and accurate isopotential mapping that facilitates catheter ablation of the ventricular tachyarrhythmias in arrhythmogenic right ventricular cardiomyopathy (ARVC).

METHODS

Thirty-two consecutive patients (26 men and 6 women, mean 37.2 +/- 13.8 years) were treated with ablation. Fourteen patients had a history of syncope/pre-syncope. Two patients had an implantable cardiac defibrillator (ICD) previously implanted.

RESULTS

There were 67 ventricular tachycardias (VTs) induced in the 32 patients. The average VT rate was 210 +/- 32.2 (130-310) bpm. There were 42 episodes of VT that had a heart rate > or =200 bpm and 24 of the 32 patients (75%) had > or =2 morphologies of VT. Regional ablation was applied by targeting the earliest VT activation sites under the guidance of non-contact mapping. Acute success was achieved in 84.4% (27/32) patients, and significant improvement was seen in 15.6% (5/32) patients as evidenced by a slower rate of VT. None of the patients experienced syncope/pre-syncope or sudden death during the 28.6 +/- 16 (9-72) month follow-up. There were no complications of the procedure. At the end of follow-up, 81.3% of the patients were free of VT without medication while the rest of the patients achieved a modified success.

CONCLUSIONS

The rapid ventricular tachyarrhythmias in ARVC patients can be abolished or improved significantly by regional RF catheter ablation under the guidance of non-contact mapping. There was no sudden cardiac arrest or death in those patients without ICD implantation. Delayed efficacy may occur in some patients after ablation.