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Notes: Pulmonary vein (PV) isolation for the treatment of atrial fibrillation is limited by procedure related complications, such as PV stenosis and occlusions. We report about a PV isolation using a circumferential cryoablation catheter which applies the ablation energy simultaneously at the entire circumference by cooling down to a minimal temperature of −80°C. (PACE 2004; 27:1024–1025)

Notes: This case report describes a patient with a sustained monomorphic VT after surgical repair of a tetralogy of Fallot (TOF). In combination with the three-dimensional electroanatomic mapping system, CARTO, and conventional mapping techniques the VT was identified as a macro-reentrant tachycardia circling around the border between pulmonary graft and right ventricular outflow tract (RVOT). A y-shaped ablation line crossing this zone was created. The VT terminated during RF application and was not inducible again. This case underlines the use of a combined conventional and three-dimensional electroanatomic mapping technique can be helpful for catheter ablation of ventricular arrhythmias in TOF patients. (PACE 2004; 27[Pt. I]:801–804)

Notes: The present study sought to investigate the electrophysiological properties of isolated pulmonary veins following successful radiofrequency (RF) catheter ablation in patients with paroxysmal atrial fibrillation (PAF). Overall, 71 pulmonary veins in 37 consecutive patients (age: 56 ± 9  years ) with recurrent PAF were targeted for RF ablation at the ostial region in order to achieve a complete functional block. Following disconnection, the incidence of dissociated pulmonary vein (PV) activity and its response to orciprenalin were studied. RF ablation abolished conduction in 67 (94%) of 71 potentially arrhythmogenic PVs after a mean of 10.7 ± 6.4  RF applications for each PV. After ablation, spontaneous dissociated automatic activity (9 to 52 beats/min, median 27) was found in 6 out of 67 isolated PVs (left superior: n = 1 , left inferior: n = 1 , right superior: n = 2 , common left PV: n = 2 ). Slight acceleration (13 to 68 beats/min, median 29) of dissociated PV activity was observed during infusion of orciprenalin. Following isolation, initiation of sustained or nonsustained local fibrillation was recorded in only two cases of the common left sided PV with preceding automatic activity. In one patient PV fibrillation occurred during orciprenalin infusion following a repetitive response to a dissociated automatic rhythm with increasing duration as well as destabilization. In the other patient, PV fibrillation occurred immediately after the occurrence of PV automaticity. Slow dissociated automatic rhythms are detectable within 9% of disconnected PVs. The unique anatomic substrate of common left PVs seem to favor the occurrence of local fibrillation following isolation. The initiation pattern of fibrillation within the isolated PV has pathophysiological implications and underlines the contribution of multiple factors to the onset and sustenance of PAF. (PACE 2003; 26:1363–1370)

Notes: This case describes a 54-year-old patient with paroxysmal atrial fibrillation and atrial flutter. Conventionally recorded local electrogram demonstrated a cycle length of 245 ms in the SVC which was conducted to the right atrium in a 2:1 fashion. The analysis of the virtual unipolar local electrogram from the noncontact mapping system demonstrated slow conduction between SVC and right atrium orthogonal to the atrial breakthrough in the upper part of the crista terminalis. RF ablation at the atrial breakthrough induced the electrical disconnection between the CVC and the right atrium. (PACE 2003; 26:1758–1761)

Notes: Background: Noninducibility of sustained atrial fibrillation (AF) after pulmonary vein isolation (PVI) has been shown to be associated with a better clinical outcome. We evaluated the role of clinical variables that could predict noninducibility of sustained AF after PVI. Methods and Results: Data were collected prospectively from 181 patients (153 male; age 54 ± 9 years) referred for ablation of drug-refractory symptomatic paroxysmal AF (duration ≤7 days). Clinical variables were evaluated with regard to their ability of predicting noninducibility of sustained AF (≤10 minutes) after PVI. Univariate analysis was performed on all collected variables followed by multivariate analysis for variables showing a P value 〈0.1. After PVI, sustained AF was noninducible in 97 (54%) patients. The following clinical variables showed a significant difference between the groups: body weight, longest AF episode, duration of AF history, presence or absence of structural heart disease, left ventricular (LV) hypertrophy, prior cardioversion, left atrial (LA) parasternal, and longitudinal diameters and LV diameters. On multivariate analysis, three independent predictors of noninducibility were identified: a shorter duration of AF episodes (AF 〈12 hours: RR 0.01 (0.002–0.06), P 〈 0.001; AF 12–48 hours: RR 0.07 (0.01–0.37), P = 0.001); LA longitudinal diameter 〈57 mm (RR 0.33 (0.13–0.82), P = 0.016); and absence of LV hypertrophy (RR 0.15 (0.04–0.63), P = 0.01). Conclusions: Shorter AF episodes, smaller LA longitudinal diameter, and absence of LV hypertrophy are independent predictors of noninducibility of sustained AF after PVI.

Notes: Background: The relative contributions of different atrial regions to the maintenance of persistent atrial fibrillation (AF) are not known. Methods: Sixty patients (53 ± 9 years) undergoing catheter ablation of persistent AF (17 ± 27 months) were studied. Ablation was performed in a randomized sequence at different left atrial (LA) regions and comprised isolation of the pulmonary veins (PV), isolation of other thoracic veins, and atrial tissue ablation targeting all regions with rapid or heterogeneous activation or guided by activation mapping. Finally, linear ablation at the roof and mitral isthmus was performed if sinus rhythm was not restored after addressing the above-mentioned areas. The impact of ablation was evaluated by the effect on the fibrillatory cycle length in the coronary sinus and appendages at each step. Activation mapping and entrainment maneuvers were used to define the mechanisms and locations of intermediate focal or macroreentrant atrial tachycardias. Results: AF terminated in 52 patients (87%), directly to sinus rhythm in 7 or via the ablation of 1–6 intermediate atrial tachycardias (total 87) in 45 patients. This conversion was preceded by prolongation of fibrillatory cycle length by 39 ± 9 msec, with the greatest magnitude occurring during ablation at the anterior LA, coronary sinus and PV-LA junction. Thirty-eight atrial tachycardias were focal (originating dominantly from these same sites), while 49 were macroreentrant (involving the mitral or cavotricuspid isthmus or LA roof). Patients without AF termination displayed shorter fibrillatory cycles at baseline: 130 ± 14 vs 156 ± 23 msec; P = 0.002. Conclusion: Termination of persistent AF can be achieved in 87% of patients by catheter ablation. Ablation of the structures annexed to the left atrium—the left atrial appendage, coronary sinus, and PVs—have the greatest impact on the prolongation of AF cycle length, the conversion of AF to atrial tachycardia, and the termination of focal atrial tachycardias.

Notes: Background: Catheter ablation of atrial fibrillation (AF) is challenging in patients with long-standing persistent AF. The clinical outcome and subsequent arrhythmia recurrence after using an ablation method targeting multiple left atrial sites with the aim of achieving acute AF termination has not been characterized. Methods: Sixty patients (mean age: 53 ± 9 years) with persistent AF (mean duration: 17 ± 27 months) were prospectively followed after catheter ablation. Catheter ablation targeting the following sites was performed in a random sequence: (i) electrical isolation of all pulmonary veins (PV); (ii) disconnection of other thoracic veins; (iii) atrial ablation at sites possessing complex electrical activity, activation gradients, or short cycle lengths. Finally, linear ablation of the LA roof and mitral isthmus was performed if sinus rhythm was not restored following energy delivery to the above sites. At 1, 3, 6, and 12 months after ablation, patients underwent clinical review and 24-hour ambulatory ECG monitoring to identify asymptomatic arrhythmia. Repeat mapping and catheter ablation was performed in any patient experiencing recurrent atrial tachycardia (AT). Clinical success was defined as the absence of any sustained atrial arrhythmia. Results: AF terminated during ablation in 52 patients (87%). The fluoroscopy and procedural durations were 84 ± 30 minutes and 264 ± 77 minutes, respectively. Three months after ablation, sustained ATs were documented in 24 patients (associated with AF in 2). Mapping in 23 patients showed a single AT in 7 while multiple ATs were observed in 16. Macroreentry was confirmed to be due to gaps in the ablation lines, while focal ATs originated from discrete sites or isthmuses near the left atrial appendage, coronary sinus, pulmonary veins, or fossa ovalis; these sites were similar to those at which the greatest impact was observed on the fibrillatory process during the initial ablation procedure. After repeat ablation, at 11 ± 6 months of follow-up, 57 patients (95%) were in sinus rhythm and 3 developed recurrent AF or AT. All patients in sinus rhythm demonstrated improved exercise capacity and all but 2 had evidence of atrial transport as assessed by Doppler echocardiography (mitral A wave velocity 34 ± 17 cm/sec) by 6 months. Conclusion: Catheter ablation of long-lasting persistent AF associated with acute AF termination achieves medium to long-term restoration and maintenance of sinus rhythm in 95% of patients. Arrhythmia recurrence in the majority of patients is AT.

Notes: Introduction: EnSite® NavX™ (NavX) is a novel mapping and navigation system that allows visualization of conventional catheters for diagnostic and ablative purposes and uses them to create a three-dimensional (3D) geometry of the heart. NavX is particularly suitable for ablation procedures utilizing an anatomic approach, as in the setting of common-type atrial flutter (AFL). The aim of this study was to compare NavX-guided and conventional ablation procedures for AFL. Methods and Results: Forty consecutive patients (32 male, 59 ± 12 years) with documented AFL were randomized to undergo fluoroscopy-guided (group I, 20 patients) or NavX-guided (group II, 20 patients) ablation, including 3D isthmus reconstruction. The same catheter setup was used in both groups. The endpoint of bidirectional isthmus block was obtained in all patients. Compared to conventional approaches, NavX-guided procedures significantly reduced fluoroscopy time (5.1 ± 1.4 min vs 20 ± 11 min, P 〈 0.01) and total x-ray exposure (5.1 ± 3.1 Gycm2 vs 24.9 ± 1.6 Gycm2, P 〈 0.01). Isthmus geometry reconstruction could be performed in all patients of group II. In 4 patients (20%) of group II, anatomic isthmus variations were detected by NavX. No significant differences in radiofrequency current applications and procedural times were found between the two groups. Conclusion: NavX technology allows geometry reconstruction of the cavotricuspid isthmus. NavX-guided ablation of AFL reduces total x-ray exposure compared to the fluoroscopy-guided approach but does not prolong procedure time.