Giuseppe Stabile

Pretreatment with verapamil in patients with persistent or chronic atrial fibrillation who underwent electrical cardioversion

OBJECTIVES To evaluate, in a prospective and randomized fashion, the efficacy of a pretreatment with verapamil (V) in reducing recurrences of atrial fibrillation (AF) after electrical cardioversion (C). BACKGROUND The increased vulnerability for AF recurrence is probably due to AF-induced changes in the electrophysiologic properties of the atria. This electrical remodeling seems to be due to intracellular calcium overload. METHODS One hundred seven patients with persistent or chronic AF underwent external and/or internal C. All patients received oral propafenone (P) (900 mg/day) three days before and during the entire period of follow-up (three months). In the first group, patients received only the P. In the second group, in adjunct to P, oral V (240 mg/day) was initiated three days before C and continued during the follow-up. Finally, in the third group, oral V was administered three days before and continued only for three days after electrical C. RESULTS During the three months of follow-up, 23 patients (23.7%) had AF recurrence. Mantel-Haenszel cumulative chi-square reached a significant level only when comparing AF free survival curves of group I versus group II and group III (chi-square = 5.2 and 4, respectively; p < 0.05). Significantly, 15 (65.2%) AF relapses occurred during the first week after cardioversion with a higher incidence in group I (10/33 patients, 30.3%) than group II (2/34 patients, 5.9%; p = 0.01) and group III (3/30 patients, 10%; p = 0.04). CONCLUSIONS Six days of oral V administration centered on the C day, combined with P, significantly reduce the incidence of early recurrences of AF compared with P alone.

Is Pulmonary Vein Isolation Necessary for Curing Atrial Fibrillation

Background—Pulmonary veins (PVs) play a pivotal role in initiating and perpetuating atrial fibrillation (AF). We investigated if PV electrical isolation from the left atrium is required for curing AF. Methods and Result—Fifty-one patients with paroxysmal or persistent AF underwent circumferential radiofrequency ablation of PV ostia performed with an anatomic approach. The end point of the ablation procedure was the recording of low peak-to-peak bipolar potentials (<0.1 mV) inside the lesions. Left atrium pacing was used to assess the conduction between the PVs and the left atrium. During a mean follow-up period of 16.6±3.9 months, 41 patients (80.4%) were free of atrial arrhythmias. When patients with and without AF recurrence were analyzed, no significant difference was observed in the mean number of PVs in which the ablation end point was reached (3.4±1.2 versus 3.7±0.87) and PVs isolated (1.5±1.4 versus 1.6±1). We noted that, although in 29 of 41 patients (71%) without AF recurrence, the ablation end point was reached in all PVs mapped, it was only possible to demonstrate the isolation of all PVs mapped in 2 patients. On the other hand, in 7 of 10 patients (70%) with AF recurrence, the ablation end point was reached in all PVs mapped, whereas one patient had all PVs isolated. Conclusions—Our findings show that with the use of a pure anatomic approach, it is possible to prevent AF in >80% of patients undergoing catheter ablation. Moreover, the isolation of PVs is not crucial for curing AF.

Predictive Value of Early Atrial Tachyarrhythmias Recurrence After Circumferential Anatomical Pulmonary Vein Ablation

Objective: Radiofrequency (RF) ablation at the ostia of the pulmonary veins (PVs) to cure atrial fibrillation (AF) is often followed by early AF recurrence. The aims of this study were to determine the rate of early atrial tachyarrhythmia as recurrence after circumferential anatomical PV ablation; to evaluate whether the early recurrence of atrial tachyarrhythmias correlates with the long‐term outcome of ablation; and to identify the predictors of early atrial tachyarrhythmias relapse.

Image integration increases efficacy of paroxysmal atrial fibrillation catheter ablation: Results from the CartoMerge™ italian Registry

AIMS The aim of this study was to investigate whether circumferential pulmonary vein (PV) isolation guided by image integration improves the procedural and clinical outcomes of atrial fibrillation (AF) ablation in comparison with segmental PV isolation and circumferential PV isolation guided by three-dimensional (3D) electroanatomical mapping alone. METHODS AND RESULTS Procedural and clinical outcomes of 573 patients who underwent their first catheter ablation for paroxysmal AF between January 2005 and April 2007 were collected from 12 centres. We evaluated three techniques: segmental ostial PV isolation (SOCA group, 240 patients), circumferential PV isolation guided by electroanatomical mapping (CARTO group, 107 patients), and circumferential PV isolation guided by electroanatomical mapping integrated with magnetic resonance/computed tomographic images of the left atrium (MERGE group, 226 patients). Procedure duration proved to be shorter in MERGE group patients than in CARTO group patients (P < 0.04), but longer than in SOCA group patients (P < 0.0001). During follow-up, atrial tachyarrhythmias relapsed more frequently in SOCA group patients (44.6%) and CARTO group patients (41.7%) than in MERGE group patients (22.6%; P < 0.0001). CONCLUSION In patients with paroxysmal AF, circumferential PV isolation guided by image integration significantly improves clinical outcome in comparison with both circumferential PV isolation guided by 3D mapping alone and with segmental electrophysiologically guided PV isolation.

VErapamil Plus Antiarrhythmic drugs Reduce Atrial Fibrillation recurrences after an electrical cardioversion (VEPARAF Study)

AIMS To evaluate the impact, on atrial fibrillation (AF) recurrences, of verapamil addition to a class IC or III antiarrhythmic drug in patients, with persistent AF, who underwent an electrical cardioversion (EC). METHODS AND RESULTS Three hundred sixty-three patients were randomized to receive four different pre-treatment protocols: oral amiodarone (group A), oral flecainide (group F), oral amiodarone plus oral verapamil (group A+V), oral flecainide plus oral verapamil (group F+V). Patients who showed an AF recurrence within 3 months were assigned to the alternative group and underwent a second EC after 48h. During 3 months of follow-up, 89 patients (27.5%) had an AF recurrence. By univariate analysis, verapamil reduced AF recurrences if added to amiodarone or flecainide (from 35% to 20%, P=0.004). Applying Cox proportional hazards regression model, only the younger age, the shorter duration of AF, and the use of verapamil were predictor of maintenance of sinus rhythm after cardioversion. In patients with primary AF recurrence, verapamil addition to group A and F patients, significantly decreased secondary AF recurrence rate as compared to group A+V and F+V patients who stopped the verapamil therapy (68% vs 88%, P=0.03). CONCLUSIONS The addition of verapamil to class IC or III antiarrhythmic drug significantly reduced the AF recurrences, that were more frequent in older patients and in patients with longer lasting AF; moreover, verapamil was effective in reducing the secondary AF recurrences, too.

Reduced fluoroscopy exposure during ablation of atrial fibrillation using a novel electroanatomical navigation system: a multicentre experience.

AIMS Catheter ablation of atrial fibrillation (AF) focuses on pulmonary vein (PV) ablation with or without additional atrial substrate modification. These procedures require significant fluoroscopy exposure. A new 3D non-fluoroscopic navigation system (CARTO(®) 3 System, Biosense Webster, CA, USA) that allows precise location visualization of diagnostic and ablation catheters was evaluated for its impact on fluoroscopic exposure during AF ablation procedures. METHODS AND RESULTS Two groups of patients were treated by our centres for drug refractory AF. One group was treated using the new CARTO(®) 3 system to guide catheter ablation (Group A, 117 patients). The other group was treated using the CARTO(®) XP system (Biosense Webster) 3 months previously (Group B, 123 patients). For both groups, circumferential PV ostia ablation was performed; PV isolation was validated using a circular catheter placed at each ostium. There was no difference in any clinical characteristics (age, sex, AF type, left atrium diameter and volume, and heart disease) among the two study groups. The mean number of PVs identified and isolated per patient was similar in both groups, as were the mean procedural duration and radiofrequency time. However, mean fluoroscopic time was significantly reduced in Group A (15.9±12.3 min) as compared with Group B (26±15.1 min) (P < 0.001). CONCLUSION This multicentre observational study demonstrates a significant reduction of fluoroscopy exposure using a new 3D non-fluoroscopic mapping system to guide AF catheter ablation.

Role of catheter-induced mechanical trauma in localization of target sites of radiofrequency ablation in automatic atrial tachycardia

OBJECTIVES We compared the efficacy of two different mapping techniques in identifying the ablation site for atrial tachycardia. Moreover, we evaluated the additive positive predictive value of mechanical interruption of atrial tachycardia to reduce the number of ineffective radiofrequency applications. BACKGROUND Radiofrequency catheter ablation has been suggested as a highly effective technique to treat drug-resistant atrial tachycardia. However, irrespective of the mapping technique utilized, success was most often achieved with a large number of radiofrequency applications. METHODS Forty-five patients with atrial tachycardia underwent radiofrequency catheter ablation. Mapping techniques included identification of earliest atrial activation and pace-mapping concordant sequence. RESULTS Atrial tachycardia was successfully treated in 42 (93.3%) of 45 patients with a mean of 3.9 radiofrequency pulses/patient. An interval between the onset of the intracavitary atrial deflection and the onset of the P wave during atrial tachycardia (AP interval) > or = 30 ms (p < 0.001) and pace-mapping concordant sequence (p = 0.01) were all significant predictors of outcome. An AP interval > or = 30 ms and a pace-mapping concordant sequence were highly sensitive (92.8%, 95% confidence interval [CI] 80.5% to 98.5%; 85.7%, 95% CI 71.5% to 94.6%, respectively) but less specific (47.8%, 95% CI 37.9% to 58.2%, 36.8%, 95% CI 27.6% to 47.2%, respectively) in identifying the site of ablation. By using atrial tachycardia mechanical interruption combined with the AP interval >30 ms or the pace-mapping concordant sequence, we obtained a specifically of 76.5% (95% CI 66.4% to 84.0%) and 73.5% (95% CI 63.2% to 81.4%), respectively, and a positive predictive value of 49.2% and 44.6%, respectively. CONCLUSIONS An AP interval > or = 30 ms and a pace-mapping concordant sequence were reliable mapping features for predicting the outcome of the ablation procedure. Mechanical interruption of atrial tachycardia improved the specificity and positive predictive value of these two mapping techniques.

Response to flecainide infusion predicts long-term success of hybrid pharmacologic and ablation therapy in patients with atrial fibrillation.

OBJECTIVES We tested the hypothesis that the response to flecainide infusion can identify patients with atrial fibrillation (AF) in whom the hybrid pharmacologic and ablation therapy reduces the recurrences of AF. BACKGROUND Infusion of class IC anti-arrhythmic drugs may promote transformation of AF into atrial flutter. Catheter ablation of atrial flutter has been demonstrated to be highly effective in preventing recurrences of atrial flutter. METHODS Seventy-one consecutive patients with paroxysmal or chronic AF, in whom flecainide infusion (2 mg/kg body weight, intravenously) determined the transformation of AF into common atrial flutter (positive response), were randomized to receive one of the following treatments: oral pharmacologic treatment with flecainide (group A, n = 23); the hybrid treatment (catheter ablation of the inferior vena cava-tricuspid annulus isthmus, plus oral flecainide) (group B, n = 24); or catheter ablation of the isthmus only (group C, n = 24). Thirty-seven patients with a negative response to flecainide, who chose to be submitted to the hybrid treatment, were selected as the control group (group D). RESULTS During a mean follow-up period of 24 +/- 7.2 months, the recurrences of AF and atrial flutter in group B (42%) were significantly lower than those in group A (78%, p < 0.001), group C (92%, p < 0.001) and group D (92%, p < 0.001). CONCLUSIONS The creation of a complete bi-directional conduction block at the inferior vena cava-tricuspid annulus isthmus, plus flecainide administration, reduces the recurrences of both AF and atrial flutter in patients with class IC atrial flutter. Moreover, the early response to flecainide is safe and reliable in identifying patients who may benefit from this therapy.

DETERMINANTS OF EFFICACY OF ATRIAL PACING IN PREVENTING ATRIAL FIBRILLATION RECURRENCES

Atrial Pacing in Atrial Fibrillation. Introduction: Several studies have shown that single or dual site atrial pacing is effective in reducing he frequency of recurrent atrial fibrillation (AF) in selected patients. However, it is still unclear what the best predictors are of long‐term efficacy of atrial pacing.

Catheter-tissue contact force for pulmonary veins isolation: a pilot multicentre study on effect on procedure and fluoroscopy time.

Aims Catheter–tissue contact is critical for effective lesion creation in radiofrequency catheter ablation (RFCA). In a multicentre prospective study, we assessed the effect of direct contact force (CF) measurement on acute procedural parameters during RFCA of atrial fibrillation (AF). Methods and results A new open-irrigated tip catheter with CF sensing (SmartTouch™, Biosense Webster Inc.) was used. All the patients underwent the first ablation procedure for paroxysmal AF with antral pulmonary vein (PV) isolation, aiming at entry and exit conduction block in all PVs. Ninety-five patients were enroled in nine centres and successfully underwent ablation. Overall procedure time, fluoroscopy time, and ablation time were 138.0 ± 67.0, 14.3 ± 11.2, and 33.8 ± 19.4 min, respectively. The mean CF value during ablation was 12.2 ± 3.9 g. Force time integral (FTI) analysis showed that patients achieving a value below the median of 543.0gs required longer procedural (158.0 ± 74.0 vs. 117.0 ± 52.0 min, P = 0.004) and fluoroscopy (17.5 ± 13.0 vs. 11.0 ± 7.7 min, P = 0.007) times as compared with those in whom FTI was above this value. Patients in whom the mean CF during ablation was >20 g required shorter procedural time (92.0 ± 23.0 vs. 160.0 ± 67.0 min, P = 0.01) as compared with patients in whom this value was <10 g. Four groin haematomas were the only complications observed. Conclusion Contact force during RFCA for PV isolation affects procedural parameters, in particular procedural and fluoroscopy times, without increasing complications.