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Solimene f;giannotti santoro m;de simone a;malacrida m;stabile g;pandozi c;pelargonio g;cauti fm;scaglione m;pecora d;bongiorni mg;arestia a;grimaldi g;russo m;narducci ml;segreti l.Pulmonary vein isolation in atrial fibrillation patients guided by a novel local impedance algorithm: 1-year outcome from the charisma study.J cardiovasc electrophysiol;year:2021;date:2021/04/15.Patient population and study design the catheter ablation of arrhythmias with high-density mapping system in the real world practice (charisma) is a prospective, single-arm, multicenter cohort study designed to describe clinical practice regarding the approach to the ablation of different arrhythmias.The study com plied with the declaration of helsinki, the locally appointed ethics committee approved the research protocol, and informed consent was obtained from all patients.In this paper, we present the analysis of 153 consecutive patients indicated for af ablation who underwent high resolution mapping and ablation guided by a local impedance algorithm in eight italian centers.All patients were followed up at the same hospital, from the time of the ablation to the last follow-up visit.After completion of the baseline evaluation, patients underwent ablation in accordance with standard clinical practice guidelines.All procedures were performed under conscious sedation or general anesthesia.Vitamin k antagonist treatment was not interrupted, while non-vitamin k anticoagulants were omitted on the morning of the procedure.A decapolar catheter (dynamic xt, boston scientific) was used to cannulate the coronary sinus.After single or double transseptal punctures under fluoroscopic guidance, intravenous un fractionated heparin boluses were administered, to maintain an activated clotting time of >300 s, and then the basket mapping catheter (orion, boston scientific) and the ablation catheter (intellanav mifi oi, boston scientific) were inserted through steerable sheaths.The orion catheter was used in combination with the rhythmia hdx mapping system (rhythmia, boston scientific) to create a three dimensional electro-anatomical voltage and activation map of the left atrium.Mapping and ablation were carried out in sinus rhythm; in patients in af, electrical cardioversion was performed to restore sinus rhythm.The ablation target for all patients was pvi only.Pvi was performed with radiofrequency energy in a point-by-point ablation pattern by the open irrigated ablation catheter.Point-by-point rf delivery was performed in such a way as to create contiguous ablation spots encircling the pvs.In patients undergoing de novo af ablation, contiguous ablation spots were created around the pv ostia where the local electrograms did not show near-field pv signals.In redo procedures, the ablation spots were deployed where conduction gaps were found after evaluation of the initial voltage/ activation map.In cases of atrial tachycardia, the ablation spots were deployed where critical points were found after evaluation of the initial voltage/activation map and the execution of entrainment maneuvers, when appropriate.Ablation on the intervenous carinae was not performed as part of the initial lesion set unless it was needed to achieve pv isolation.Ablation was guided by the magnitude and time-course of impedance drop during rf delivery.The recommended maximum distance between each ablation spot (center-to-center) was /= 40 ohms was observed.Successful single rf ablation was defined as a reduction in signal voltage by at least 50% and the inability to capture local tissue on pacing.Targeted signal was evaluated through the egm recordings from the micro-electrodes (i.E., the largest mifi signal).Pacing maneuvers were performed from each lesion site at the end of the pvs circle.Pacing output was set at 10 v at 2 ms, with a pacing cycle length of 600 ms.Unsuccessful lesions were defined as those which resulted in continued ability to capture tissue.Power settings were at the individual operator's discretion, within the range of 30 to 35 w, depending on the left atrial segment considered.The endpoint of ablation was pvi, as assessed on the basis of entry and exit block by means of the 64 pole orion catheter placed sequentially in each of the pvs.In the absence of first-pass pv isolation (i.E., no isolation upon completion of the encirclement of ipsilateral veins), pv isolation was accomplished by means of additional rf applications at the investigator's discretion.Baseline tissue impedance and impedance drop for each ablation lesion were measured both from the micro-electrodes of the catheter and from the maestro generator (maestro 4000, boston scientific) (generator impedance [gi]).The user interface displays the maximum li value of all three miniature-electrode li measurements.The characteristics of measurement functioning have already been described elsewhere.When available, videos of the ablation procedures were exported from the mapping system, displaying the procedure in real time.Rf current applications were then retrospectively analyzed.For the purpose of this analysis, we excluded all lesions with the following characteristics: catheter instability, rf deliveries outside pvs, interference with the orion catheter, and rf application lasting less than 10 seconds.Complications were reported on the case report form and collected during follow-up.After ablation, anticoagulation and antiarrhythmic drug therapy (adt) were continued.At 3 months, anticoagulation was continued according to stroke risk, whereas adt was continued at the discretion of the treating physician.Clinical evaluation and ecg were performed at 1, 3, 6, and 12 months.Holter ecg was performed at 3, 6, and 12 months post ablation or in the case of symptoms.Arrhythmia recurrences within the first 3 months (blanking period) were classified as early recurrences and were not considered procedural failures.Freedom from recurrence was defined as the 1-year absence of af, atrial tachycardia, and atrial flutter (af/at/afl) lasting continuously for >30 seconds, as recorded by any post-ablation electrocardiogram (ecg) modality.One hundred fifty three consecutive patients were enrolled: patients had an indication mostly for paroxysmal af ablation (n = 94, 61.4%) and the majority of procedures were de novo pvi (n = 96, 62.7%).In about half of the patients (n = 73, 47.7%) the first occurrence of atrial arrhythmia was reported more than 1 year before the procedure.Besides af, 21.6% of patients had a history of atrial flutter (afl), and 5.2% a history of at.The mean procedure duration was 136 +/- 47 min and the mean fluoroscopy time was 17.1 +/- 8 min.A total of 7598 rf applications were delivered, with a median number of 44 27-66 ablation spots and a median rf pulse duration time of 33 24-48 seconds, without any steam popping.At the end of the procedures, all pvs had been successfully isolated in all study patients.No major complications, including atrioesophageal fistula or tamponade, were reported during or after the procedures.Minor complications were reported in nine patients (5.9%) after the procedure: vascular complications at the puncture site in 5 (three groin hematomas, one pseudoaneurysm, and one arteriovenous fistula) and pericarditis with mild pericardial effusion in 4.Conservative treatment and medical therapy were effective in all cases.During a mean follow-up of 366 +/- 130 days, 18 patients (11.8%) suffered an af/at recurrence after the 90 day blanking period.Specifically, 10 (6.5%) patients had af recurrence only, 7 (4.6%) had at recurrence only and 1 (0.7%) experienced both events.The recurrence rate was higher in patients with persistent af (11 out of 59, 18.6%) than in those with paroxysmal af (7 out of 94, 7.4%; p =.0426), whereas no differences emerged between procedure types (10 out of 96, 10.4% for de novo procedures vs.8 out of 57, 14% for redo procedures, p =.6052).De novo paroxysmal af procedures resulted in the lowest recurrence rate (4 out of 58, 6.9%), whereas redo persistent af procedures showed the highest rate (5 out of 21, 23.8%).The time to recurrence was slightly longer in paroxysmal af and comparable between procedure types.
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