Radiofrequency catheter ablation of multiple morphologies of ventricular tachycardia by targeting a single region of the left ventricle

Sinus Rhythm Electrogram Shape Measurements are Predictive of the Origins and Characteristics of Multiple Reentrant Ventricular Tachycardia Morphologies

INTRODUCTION

During clinical electrophysiologic study, multiple clinical tachycardia morphologies often can be induced in the infarct border zone, and all morphologies must be targeted for ablation therapy to be successful. Analysis of sinus rhythm electrogram shape for localizing figure-of-eight reentrant circuits in cases of multiple morphologies is proposed.

METHODS AND RESULTS

Sinus rhythm activation maps were constructed from bipolar electrograms acquired at 196 to 312 sites in the epicardial border zone in 10 postinfarction canine hearts. In each heart, at least two distinct figure-of-eight reentrant ventricular tachycardia morphologies were inducible by premature electrical stimulation, as determined by activation maps of sustained tachycardias. Sinus rhythm maps were used to predict the location of the isthmus (central common pathway [CCP]), which is the protected region of the circuit bounded by arcs of block (mean accuracy 76.7 +/- 4%). Although reentrant circuits differed, the positions of the entrance point of each CCP were common. The location of the line that would span the CCP at its narrowest width also was estimated (mean accuracy 91.3 +/- 5%). Ablation at this line is expected to prevent reentry recurrence. In one test experiment, ablation prevented recurrence of both sustained reentrant tachycardia morphologies.

CONCLUSION

Sinus rhythm electrogram analyses are useful for (1) localizing multiple reentrant circuits with differences in morphology that are inducible by premature stimulation in the infarct border zone, and (2) locating and orienting the position of a linear lesion for preventing recurrence of all morphologies with minimal damage to the heart.

Management of postinfarct ventricular tachycardias

The clinical profile of patients with postinfarct VT has changed in the past two decades. Along with these changes, existing treatments have improved, and entirely new therapeutic approaches have been developed. The expanded range of treatment options has made postinfarct VT a less imposing clinical problem than it once was. Emerging therapies promise to make an even greater beneficial impact. The challenge in treating patients with postinfarct VT has changed from merely keeping patients alive to keeping up with innovations in therapy that can provide them with a better quantity and quality of life.

Radiofrequency catheter ablation of multiple haemodynamically unstable ventricular tachycardias in a patient with surgically repaired tetralogy of Fallot

A patient with repaired tetralogy of Fallot presented with recurrent syncope and had multiple haemodynamically unstable ventricular tachycardias unresponsive to antiarrhythmic medications. Ventricular tachycardias became haemodynamically tolerated with amiodarone, procainamide and dopamine, permitting activation and entrainment mapping. Radiofrequency ablation of three tachycardia circuits was performed. Ventricular tachycardia could not be induced 1 week, and 3 and 9 months later. Radiofrequency ablation is feasible for multiple, haemodynamically unstable ventricular tachycardias in repaired tetralogy of Fallot.

Cardiac electrophysiology studies and ablation procedures: a literature review

This literature review is focused on issues related to the development and usefulness of cardiac electrophysiology studies and ablation procedures. During the past decade, the efficacy of these developments has been proven. The resultant emergence of specialists trained as electrophysiologists represents an important milestone in the advancement of cardiology departments internationally. The majority of research papers on the subject have been published within the past 5 years. Most of the research has evolved from North America and Britain. On searching the literature, it was found that many gaps remain. There is a striking dearth of documented data regarding electrophysiology studies and ablation therapy within the Irish medical and nursing literature, and no previous literature review on the topic was found in a wider search. This paper provides an overview of the strengths and weaknesses associated with these procedures.