Differences in scar lesion formation between radiofrequency and cryoballoon in atrial fibrillation ablation: a comparison study using ultra-high-density mapping.

AIMS: Atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI) is usually associated to conduction gaps in pulmonary veins (PVs). Our objective was to characterize gaps in patients with recurrences after a first radiofrequency (RF) or cryoballoon (CB) PVI procedure, using a high-density mapping (HDM) system. METHODS AND RESULTS: Fifty patients with AF recurrence after a first PVI procedure (pre-RF 25 patients; pre-CB 25 patients) were included at two centres. Activation map (AM) and voltage map (VM) of the left atrium and PVs were built using the HDM Rhythmia® system. Superior PVs were reconnected more frequently in both groups. Right PVs were reconnected more frequently in pre-RF patients. Pre-RF patients had more reconnected veins than pre-CB patients (mean ± standard deviation: 3.00 ± 0.96 vs. 1.88 ± 1.13; P < 0.001) and more gaps (4.84 ± 2.06 vs. 2.16 ± 1.49; P < 0.001). Gaps in the VM were wider in pre-CB patients (16.5 ± 9.5 mm vs. 12.1 ± 4.8 mm; P = 0.006). There was a gap in 179 of the 800 PV segments analysed (22%); 52% were identified in both AM and VM maps; 39% only in the AM and 8% only in the VM. The highest sensitivity and specificity for gap detection was obtained with VM in pre-CB patients and with AM in pre-RF patients. CONCLUSION: In conclusion, HDM seems to be a useful and precise tool to detect conduction gaps after a first PVI procedure. The anatomical pattern and location of gaps depends on the technique used previously, usually being multiple, smaller, and better detected by AM after RF, and fewer, wider, and better detected by VM after CB.

Time-to-Effect-Based Dosing Strategy for Cryoballoon Ablation in Patients With Paroxysmal Atrial Fibrillation: Results of the plusONE Multicenter Randomized Controlled Noninferiority Trial.

BACKGROUND: The optimal dosage of cryotherapy during cryoballoon ablation of pulmonary veins is still unclear. This trial tested the noninferiority of a novel, individualized, cryotherapy-dosing strategy for each vein. METHODS AND RESULTS: This prospective, randomized, multicenter, noninferiority study included 140 patients with paroxysmal atrial fibrillation, which was refractory to antiarrhythmic drugs. Patients were randomly assigned to a conventional strategy of 180-second cryoballoon applications per vein with a bonus freeze (control group, n=70) or to a shorter-time application protocol, with 1 application that lasted the time required for electric block time to effect plus 60- and a 120-second freeze bonus (study group, n=70). Patients were followed with a long-term monitoring system of 30 days. At 1-year follow-up, no difference was observed in terms of free atrial fibrillation-recurrence rates: 79.4% in control versus 78.3% in study group (Δ=1.15%; 90% confidence interval, -10.33% to 12.63%; P=0.869). Time to effect was detected in 72.1% of veins. The control and study groups had similar mean number of applications per patient (9.6±2 versus 9.9±2.4; P=0.76). Compared with controls, the study group had a significantly shorter cryotherapy time (28.3±7 versus 19.4±4.3 minutes; P<0.001), left atrium time (104±25 versus 92±23 minutes; P<0.01), and total procedure time (135±35 versus 119±31 minutes; P<0.01). No differences were observed in complications or acute reconnections. CONCLUSIONS: The new time-to-effect-based cryotherapy dosage protocol led to shorter cryotherapy and procedure times, with equal safety, and similar acute and 1-year follow-up results, compared with the conventional approach. CLINICAL TRIAL REGISTRATION: URL: https://clinicaltrials.gov. Unique identifier: NCT02789358.

Medium-term results of cryoballoon ablation of the pulmonary veins in patients with paroxysmal and persistent atrial fibrillation. First experience of a Spanish center.

PURPOSE: Cryoballoon ablation of the pulmonary veins (CAPV) is a new technique that could have similar results to radiofrequency procedures, but with fewer complications. We analyzed the outcomes and safety of this technique in a consecutive cohort of patients with atrial fibrillation (AF). METHODS: A total of 63 patients with paroxysmal (n = 40) or persistent (n = 23) AF were studied. Patient follow-up was performed at 3 months and then every 6 months with 72-h continuous electrocardiographic recordings. RESULTS: A total of 262 pulmonary veins were treated; 60.3 % of the cases presented normal pulmonary vein drainage with 4 pulmonary veins, and 23.8 % of the cases presented a common left-sided antrum. Complete isolation of all veins was achieved in 95.2 % of cases with 10.3 ± 2.8 (mean ± standard deviation) applications per patient. Transient right phrenic nerve injury was the most common complication (4.7 %). Median follow-up was 5.5 months. The probability of being free of recurrence at 1 and 2 years was, respectively, 86.2 and 72.2 % for paroxysmal AF and 49 and 36.4 % for persistent AF (P = 0.012). Patients with structural heart disease experienced recurrence more often than patients with a normal heart (62.5 versus 24.5 %; P = 0.03). CONCLUSIONS: CAPV appears to be a safe and effective procedure for the treatment of patients with AF, particularly those with paroxysmal AF and no structural heart disease.

La ablación transcatéter: una técnica de la cardiología práctica diaria / Transcatheter ablation. A routine cardiology technique

La ablación transcatéter, especialmente con energía de radiofrecuencia, ha sido el avance más significativo de la arritmología y uno de los de mayor impacto global en la cardiología de los últimos 25 años. Su introducción clínica en 1982 para la interrupción de la conducción auriculoventricular se siguió, a principios de los noventa, de la demostración amplia de su eficacia en el tratamiento curativo de pacientes con vías accesorias y en pacientes con taquicardias por reentrada nodal. Posteriormente se añadieron el aleteo auricular, las taquicardias auriculares y las taquicardias ventriculares idiopáticas. El abordaje de las taquicardias ventriculares asociadas a cardiopatía estructural permite en muchos casos el control total de la arritmia, mientras que en cualquier caso puede utilizarse como parte de una terapia híbrida, junto con los fármacos y los dispositivos implantables. Por último, las técnicas de ablación de la fibrilación auricular, en pleno desarrollo, han venido a completar una oferta terapéutica que el cardiólogo clínico puede y debe ofrecer a los pacientes con arritmias (AU)

Transcatheter ablation, especially with radiofrequency energy, is the most significant advance in arrhythmology and is one of the developments that has had the greatest impact on the whole field of cardiology over the last 25 years. It was introduced into clinical practice in 1982 to block atrioventricular conduction. This was followed at the beginning of the 1990s by widespread evidence that the technique was effective as curative treatment for patients with accessory pathways or atrioventricular nodal reentrant tachycardia. Subsequently, atrial flutter, atrial tachycardia and idiopathic ventricular tachycardia were added to the list. Using the technique to treat ventricular tachycardias associated with structural heart disease enables these arrhythmias to be completely controlled in many cases. In addition, the technique can also be used as part of hybrid therapy together with drugs and implantable devices. Finally, techniques for ablating atrial fibrillation, which are currently under development, complete the range of treatment choices that clinical cardiologists can and should offer to patients with arrhythmias (AU)