Complications of catheter ablation for ventricular tachycardia

With the increasing literature demonstrating benefits of catheter ablation for ventricular tachycardia (VT), the number of patients undergoing VT ablation has increased dramatically. As VT ablation is being performed more routinely, operators must be aware of potential complications of VT ablation. This review delves deeper into the practice of VT ablation with a focus on periprocedural complications.

A new mapping method to estimate exit sites of ventricular arrhythmias using intracardiac echocardiography and M-mode for catheter ablation

Background

Catheter ablation of premature ventricular complexes (PVCs) has been used as a curative therapy in many cases. Intracardiac ultrasound with a magnetic sensor probe has recently become available for catheter ablation. In this study, we assessed a new mapping method, contraction mapping, for determining the optimal ablation sites using intracardiac ultrasound and M-mode. This study sought to assess the accuracy of the new mapping method using intracardiac echocardiography.

Methods

Eighteen patients (10 males and eight females; mean age, 63±12 years) with 104 mapping points diagnosed as idiopathic PVCs were included in this study. At the mapping points, the time interval from the onset of the QRS to the onset of the contraction (QRS-c-time) and the local activation time were measured using M-mode with an intracardiac echo probe and using the conventional method. The correlation between the QRS-c-time and local activation time were studied.

Results

The QRS-c-time was significantly correlated with the local activation time (activation time=−66.8+0.882 * QRS-c-time, R2=0.728, p<0.0001).

Conclusions

Contraction mapping could help determine the local activation time without the delivery of a catheter to the mapping points.

Epicardial scar in a patient with no apparent heart disease

A 35-year-old man, who had an episode of aborted sudden cardiac death due to ventricular fibrillation, suffered from multiple storms of ventricular tachycardia (VT). Conventional cardiac examinations did not reveal any structural heart diseases, and he had been treated by an implantable cardioverter defibrillator since 2007. At the latest admission, epicardial but not endocardial voltage mapping revealed a small area of low voltage at the left ventricular (LV) postero-lateral wall where a delayed potential was recorded during sinus rhythm. Excellent pacemapping with a prolonged stimulus to QRS interval was obtained from the area, and a mid-diastolic potential was recorded during the VT. Radiofrequency application terminated the VT and any VT became noninducible after the ablation. In some patients diagnosed as LV-VT with no apparent heart disease, arrhythmogenic substrate may exist on the epicardial surface of the ventricle.