Radiofrequency Ablation of Concealed Left Free-Wall Accessory Pathways Without Coronary Sinus Catheterization:

Ablation of Concealed Accessory Pathways. Introduction: Feasibility of radiofrequency (RF) ablation using a two-catheter technique without coronary sinus catheterization was studied in 100 consecutive patients with a single concealed left free-wall accessory path-way.
Methods and Results: Tachycardia was induced by electrical stimulation in the right atrium/right ventricle, and the presence of a concealed left free-wall accessory pathway was suggested electrocardiographically (negative P wave in leads I and/or a VL during orthodromic tachycardia) or by earlier atrial activation in the pulmonary artery compared to the high right atrium. Mapping of the mitral annulus was performed during right ventricular pacing or orthodromic tachycardia, and RF energy was applied at the site with the earliest retrograde atrial activation. Ablation was considered effective if tachycardia could not be induced, and if VA dissociation or exclusive retrograde nodal conduction was observed. Ablation was initially successful in 98 of 100 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. There were no complications related to the procedure. At a mean follow-up of 22 ± 13 months, two patients experienced tachycardia recurrence and required a second procedure, which was successful.
Conclusions: Our results suggest that RF catheter ablation of concealed left free-wall accessory pathways can be safely, effectively, and rapidly performed using a simplified two-catheter technique with no need for coronary sinus catheterization.     

Radiofrequency Catheter Ablation of Atriofascicular Accessory Pathways Guided by Discrete Electrical Potentials Recorded at the Tricuspid Annulus

Background: The purpose of this study was to test the feasibility of using the recording of discrete electrical potentials to guide radiofrequency catheter ablation of atriofascicular accessory pathways with Mahaim-like properties. Methods and Results: Four patients (3 females, 1 male) who fulfilled criteria for having atriofascicular accessory pathways with Mahaim-like properties and preexcited reciprocating tachycardia underwent radiofrequency catheter ablation. The mean age was 35 years (range 27–47). Symptoms were present for a mean of 10.5 years (range 6–18). Recording of discrete electrical potentials of the atriofascicular pathway was attempted by mapping the tricuspid annulus in sinus rhythm, during atrial pacing, and during reciprocating tachycardia. During atrial pacing, a mean of seven radiofrequency pulses (range 1–14), delivered to the tricuspid annulua at the area where electrical potentials were recorded, eliminated conduction through the atriofascicular accessory pathway in all patients. No complications occurred. Tachycardia did not reoccur during a mean follow-up of 5 months (range 3–9). Conclusions: 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.     

Radiofrequency Ablation of Anteroseptal, Para-Hisian, and Mid-Septal Accessory Pathways Using a Simplified Femoral Approach

Feasibility of RF ablation using a simplified two-catheter 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. BF 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 BF 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 ± 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. RF 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.     

Sotalol and a Broken Heart

Sotalol and a Broken Heart. An 82‐year‐old woman with persistent atrial fibrillation underwent successful electrical cardioversion and was begun on sotalol. After 3 days of in‐hospital observation she had only mild lengthening of the QT interval. Two weeks later in clinic, the day after her husband's unexpected death, she was noted to have profound QT interval prolongation. Although she was asymptomatic and echocardiography did not disclose regional wall motion abnormalities consistent with takotsubo cardiomyopathy, she probably had a forme fruste of stress cardiomyopathy. Following emotional trauma, a period of heightened vigilance for ventricular proarrhythmia is probably warranted in women treated with antiarrhythmic drugs that lengthen repolarization. (J Cardiovasc Electrophysiol, Vol. 21, pp. 207‐210, February 2010)     

Enhanced Detection Criteria in Implantable Defibrillators

Enhanced Tachycardia Detection Algorithm introduction: Enhanced detection criteria in third-generation implantable defibrillators have been implemented to avoid inappropriate therapy of fast supraventricular arrhythmias. We prospectively analyzed the use of these criteria in patients with an implantable defibrillator with electrogram storing capability. Methods and Results: In 82 consecutive patients with a Guidant-CPI implantable defibrillator, sudden onset > 9% and stability < 40 msec were systematically programmed in zone 1 of therapy together with a sustained rate duration security mechanism. All detected tachycardia episodes were analyzed. The study population consisted of 59 patients who had at least one episode of tachycardia detected in zone 1 during follow-up. The tachycardia rate in zone 1 never exceeded 210 beats/min. Twenty patients had no episodes during follow-up, and three patients had episodes detected exclusively in zone 2 of therapy. Supraventricular arrhythmias were detected frequently in the ventricular tachycardia zone (193 of 690 tachycardia episodes in 23 of 59 patients). Use of sudden onset was very effective in detecting sinus tachycardias (65 of 67 episodes), and stability was very useful in detecting atrial fibrillation (31 of 32 episodes). However, sensitivity in detecting ventricular tachycardia was only 90% (451 of 497 episodes). Application of the sustained rate duration criterion allowed appropriate treatment of all ventricular tachycardia episodes, increasing sensitivity to 100%; however, specificity in appropriate non-treatment of supraventricular decreased from 96% to 83%. Subsequent analysis of different algorithms applied to our data showed that sudden onset > 9% and stability < 40 msec was the algorithm with the best specificity and sensitivity. Conclusion: 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.