c8

Is Fascicular Activation the Target for Ablation of Left Outflow Tract Ventricular Tachycardia

Ardashev AV, MD, PhD, ScD, Klimov VP, MD, Zhelyakov EG, MD, Shavarov AA, MD, Steklov VI, MD, PhD, Korneev NV, MD, hD

Interventional Cardiology Center, Burdenko Head Veterans / Military Clinical Hospital, Moscow, Russia

CASE REPORT

The 23 year-old woman who had ventricular premature beats (VPB) and episodes of almost asymtomatic persistent short-runs of ventricular tachycardia (VT). The rhythm disorder was revealed at routine medical follow-up on ECG during pregnancy. She was given sotalol without effect. Delivery has passed safely, the child was born healthy, however arrhythmia was kept after pregnancy. She has a short-term episode of loss of consciousness about one year ago. Arrhythmogenic dysplasia of right ventricle with expansion, according our interpretation, on the left chambers (signs of right ventricule aneurysm at MRI and ventriculographia) was diagnosed. The ejection fraction at ECHO was 56 %. The morphology of VPB corresponded to a site located in the left ventricular outflow tract (LVOT). Taking into account inefficient antiarrhythmic therapy we decided to perform RFA of arrhythmogenic focus. By transaortic approach the sinuses of Valsalva were contrasted consequently. Electrogramms were registered with use of systems GE Prucka CardioLab and Siemens RECOR. Activation and pace-mapping techniques were performed. The optimum site for ablation was defined in the left sinus of Valsalva about 1 sm left from ostium of a trunk of left coronary artery (1). Pre-QRS interval was 50 ms (see fig.1). During pace-mapping from distal pair of ablation catheter there were no fusion observed according to 12-leads ECG. RFA in this area under constant fluoroscopic control has resulted in disappearance of VPB within 15 seconds of RFA and its absence in control period within 24 hours after procedure verified. We registered so-called fascicular activation (FA) on the ablation electrode while of mapping (fig.1), however pre-QRS interval and morphology ventricular stimulation complexes were not optimal during pace-mapping in this site. These potentials had different coupling intervals with clinical extrasystoles (fig.1) and PVB appearance coupled with FA was of doubt.

Figure 1 (A, B, C). From top to bottom: I, II, III, V1 ECG leads, bipolar and unipolar mapping channels . Fascicular activation with different coupling intervals 80 ms (A), 140 ms (B) and 20 ms (C). Pace-mapping in this side was not optimal. Pre-QRS interval is 15 ms.

As shown in figure 2 the target for ablation was not accompanied by registration FA. Moreover, we registered FA from this site after successful ablation (fig.3).

Figure 2. From top to bottom: I, II, III, V1 ECG leads, bipolar and unipolar mapping channels . The optimal activation and pace-mapping site. Pre-QRS interval is 40 ms. RF application was successful. There is no fascicular activation.

Figure 3. From top to bottom: I, II, III, V1 ECG leads, bipolar and unipolar mapping channels . Fascicular activation after successful ablation .

DISCUSSION

The modern criteria using for mapping of idiopathic ventricular arrhythmias might include an identification of pre-QRS interval 40-60 ms and reasonable pace-mapping according to 12-leads ECG (2, 3, 4). According to recently appeared works it is estimated, that the registration of FA to be the target for ablation. In our data while of mapping of ventricular arrhythmias (VPB and VT) с of RVOT and LVOT, the FA was registered in 5 cases. The ablation in this area was successful at 4 patients, and in one case developed ventricular fibrillation with subsequent effective defibrillation and with the clinical arrhythmia. The clinical example demonstrates, that FA could not be a target for effective RFA, moreover these potentials were registered even after successful RF application. We suppose, that the FA is dissociated from a proper V-EG activity in this LVOT case. Though other four cases cannot completely deny the significance of Purkinje potentials as a target for ceseasing of ventricular arrhythmias.

REFERENCES

• Hachiya H, Aonuma R, Yamauchi Y. Successful radiofrequency catheter ablation of left ventricular outflow tract tachycardia from the coronary cusp. PACE 2000; 23(4), part II; 595.

• Rahilly GT, Prystowsky EN, Zipes DP, et al. Clinical and electrophysiologic findings in patients with repetitive monomorphic ventricular tachycardia and otherwise normal electrocardiogram. Am J Cardiol. 1982; 50:459-468.

• Coggins DL, Lee RJ, Sweeny J, et al. Radiofrequency catheter ablation as a cure for idiopathic tachycardia of both left and right ventricular origin. J Am Coll Cardiol. 1994; 23:1333-1341.

• Wilber DJ, Baerman J, Olshansky B, et al. Adenosine-sensitive ventricular tachycardia. Clinical characteristics and response to catheter ablation. Circulation. 1993; 87:126-134.