Mapping and ablation of atypical AVNRT from the morphologic left atrium in a patient with dextrocardia and situs inversus

A 75-year-old woman with dextrocardia, situs inversus, and subpulmonic outflow obstruction presented with recurrent supraventricular tachycardia (SVT). This SVT was easily inducible during electrophysiology study, and pacing maneuvers during SVT were consistent with atypical, slow-slow atrioventricular nodal reentrant tachycardia (AVNRT). The His bundle was identified in the low postero-septal morphologic right atrium, at the typical anatomic site for slow pathway ablation of AVNRT. Mapping of the retrograde earliest atrial electrogram during AVNRT localized this site to the mid-septal morphologic left atrium, and cryoablation at this site terminated the AVNRT and rendered it noninducible

Combined use of cryoballoon and focal open-irrigation radiofrequency ablation for treatment of persistent atrial fibrillation: Results from a pilot study

Background: Pulmonary vein isolation (PVI) achieved using a cryoballoon has been shown to be safe and effective. This treatment modality has limited effectiveness for treatment of persistent atrial fibrillation (AF). Objective: The purpose of this study was to evaluate a combined approach using a cryoballoon for treatment of PVI and focal radiofrequency (RF) left atrial substrate ablation for treatment of persistent AF. Methods: Twenty-two consecutive patients with persistent AF were included in the study. PVI initially was performed with a cryoballoon. Left atrial complex fractionated atrial electrograms (CFAEs) then were ablated using an RF catheter. Finally, linear ablations using the RF catheter were performed. Results: Eighty-three PVs, including five with left common ostia, were targeted and isolated (100%). Seventy-seven (94%) of 82 PVs targeted with the cryoballoon were isolated, and 5 (6%) required use of RF energy to complete isolation. A mean of 9.7 \uc2\ub1 2.6 cryoablation applications per patient was needed to achieve PVI. Median time required for cryoablation per vein was 600 seconds, and mean number of balloon applications per vein was 2.5 \uc2\ub1 1.0. In 19 (86%) patients in whom AF persisted after PVI, CFAE areas were ablated using the RF catheter. Two cases of transient phrenic nerve paralysis occurred. After a single procedure and mean follow-up of 6.0 \uc2\ub1 2.9 months, 86.4% of patients were AF-free without antiarrhythmic drugs. Conclusion: A combined approach of cryoablation and RF ablation for treatment of persistent AF is feasible and is associated with a favorable short-term outcome

A combined anatomic and electrophysiologic substrate based approach for sudden cardiac death risk stratification

BACKGROUND: Although left ventricular ejection fraction (LVEF) is the primary determinant for sudden cardiac death (SCD) risk stratification, in isolation, LVEF is a sub-optimal risk stratifier. We assessed whether a multi-marker strategy would provide more robust SCD risk stratification than LVEF alone. METHODS: We collected patient-level data (n = 3355) from 6 studies assessing the prognostic utility of microvolt T-wave alternans (MTWA) testing. Two thirds of the group was used for derivation (n = 2242) and one-third for validation (n = 1113). The discriminative capacity of the multivariable model was assessed using the area under the receiver-operating characteristic curve (c-index). The primary endpoint was SCD at 24 months. RESULTS: In the derivation cohort, 59 patients experienced SCD by 24 months. Stepwise selection suggested that a model based on 3 parameters (LVEF, coronary artery disease and MTWA status) provided optimal SCD risk prediction. In the derivation cohort, the c-index of the model was 0.817, which was significantly better than LVEF used as a single variable (0.637, P < .001). In the validation cohort, 36 patients experienced SCD by 24 months. The c-index of the model for predicting the primary endpoint was again significantly better than LVEF alone (0.774 vs 0.671, P = .020). CONCLUSIONS: A multivariable model based on presence of coronary artery disease, LVEF and MTWA status provides significantly more robust SCD risk prediction than LVEF as a single risk marker. These findings suggest that multi-marker strategies based on different aspects of the electro-anatomic substrate may be capable of improving primary prevention implantable cardioverter-defibrillator treatment algorithms