Programming sudden onset and stability detection criteria with a sustained rate duration safety net for triggering tachycardia therapy results in appropriate device management in most patients with supraventricular and slow (< 210 beats/min) ventricular tachycardias.

Recording of discrete electrical potentials at the tricuspid annulus identifies an optimal ablation site where radiofrequency current can safely eliminate conduction through atriofascicular accessory pathways with Mahaim-like properties.

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Ablation of Concealed Accessory Pathways. Introduction: Feasibility of radiofrequency (RF) ablation using a two-catheter tecbtiique without coronary sinus catbeterization was .studied in 100 consecutive patients witb a single concealed left free-wall accessory patbway.Methods and Results: Tacbycardia was induced by electrical stimulation in the right atriuni/rigbt ventricle,, and tbe presence of a concealed left free-wall accessory patbway was suggested electrocardiograpbically (negative P wave in leads I and/or aVL during ortbodrotnic tachycardia) or by earlier atrial activation in tbe pulmonary artery compared to tbe bigb rigbt atrium. Mapping of tbe mitral iinnulus was performed during right ventricular pacing or orthodromic tacbycardia,, and RF energy was applied at tbe site with tbe earliest retrograde atrial activation. Ablation was considered effective if tacbycardia could not be induced, and if VA dissociation or exclusive retrograde nodal conduction was observed. Ablation was initially successful in 98 of I(M) patients. Mean number of radiofrequency pulses were 3.2 ± 2. Mean fluoroscopy time and total procedure time was 14 ± 9 and 107 ± 32 minutes, respectively. Tbere were no complications related to tbe procedure. At a mean follow-up of 22 ± 13 months, two patients experienced tacbycardia recurrence and required a second procedure, wbicb was successful.Conclusions: Our results suggest tbat RF catheter ablation of concealed left free-wall accessory pathways can be safely, effectively, and rapidly performed using a simplified two-catbeter tecbnique witb no need for coronary sinus catheterization.

Radiofrequency Ablation of Anteroseptal, Para-Hisian, and Mid-Septal Accessory Pathways Using a Simplified Femoral Approach. Feasibility ofRF ablation using a simplified two-catlwter technique from a femoral approach was studied in 97 consecutive patients with a manifest or concealed accessory pathway located at the anteroseptal mid-septal, and para-Hisian areas. HF was applied at the site with the shortest V-delta interval or the earliest retrograde atrial activation during orthodromic tachycardia or right ventricular pacing. Ablation was initially successful in 88 of 97 patients (91 %). Success rate was 94% (16/17) for anteroseptal, 94% (39/43) for para-Hisian, and 89% (33/37) for mid-septal accessory pathways, without differences between manifest and concealed pathways for any of the locations. Mean number of HF pulses was 8 ± 5 for anteroseptal, 6 ± 6 for mid-septal, and 12 ± 13 for para-Hisian accessory pathways. Two patients (2%) required implantation of a permanent pacemaker for complete A V block. At a mean follow-up of 27 it: 14 months, four patients with previous manifest preexcitation experienced resumption of intermittent preexcitation, but only one required a second successful procedure for recurrence of palpitations. HF ablation can be used effectively and without impairment of normal AV conduction in the majority of patients with anteroseptal, para-Hisian, and mid-septal accessory pathways using a simplified two-catheter technique from a femoral approach. (PACE 1998; 21 [Pt. Ij:735-74l) radiofrequency catheter ablation, accessory pathways, anteroseptal, mid-septat, para-Hisian