Prevalence and predictive factors of left atrial tachycardia occurring after second-generation cryoballoon ablation of atrial fibrillation.

INTRODUCTION: Assess the prevalence and predictors of left atrial tachycardia (LAT) after cryoballoon ablation of pulmonary veins. METHODS AND RESULTS: Patients who underwent catheter ablation of pulmonary veins with a second-generation cryoballoon for symptomatic paroxysmal (151 of 270, 56%) or persistent (119 of 270, 44%) atrial fibrillation were entered in a single-center prospective registry. Patients who experienced postcryoballoon LAT (pcryo-LAT) were selected on the basis of 12-lead ECG characteristics. Left atrial origin was confirmed during conventional EP study and electroanatomical activation mapping, and patients were treated by RF catheter ablation. Pcryo-LAT was observed in 15 (5.6%) of 270 patients and was attributed to a reentrant mechanism in 11 patients (73%). The other four cases of pcryo-LAT were due to focal atrial tachycardia associated with reconnection of one pulmonary vein. In comparison with patients who remained in sinus rhythm, LA area (HR = 1.09; CI 1.01, 1.2; P = 0.02), LVEF (HR = 0.94; CI 0.90, 0.97; P < 0.001), and LVEF <50% (HR = 8.5; CI 3.1, 23.6; P < 0.001) were predictors of pcryo-LAT. After multivariate Cox analysis, only left ventricular ejection fraction < 50% remained predictive of pcryo-LAT, (HR = 7.8, CI 2.3 26.7, P = 0.002). With a mean survival of 23 months, 73% of patients who experienced pcryo-LAT were in sinus rhythm versus 78% of patients without pcryo-LAT (log rank P = 0.85). CONCLUSION: The prevalence of pcryo-LAT in patients with atrial fibrillation is low. Left ventricular ejection fraction < 50% is associated with an increased risk of pcryo-LAT. When treated by RF catheter ablation, the presence of pcryo-LAT is not a predictive factor of subsequent recurrence of atrial fibrillation during follow-up.

Feasibility and safety of temporary subcutaneous venous figure-of-eight suture to achieve haemostasis after ablation of atrial fibrillation.

AIMS: This prospective study was carried out to assess the feasibility and safety of venous figure-of-eight suture to achieve haemostasis after atrial fibrillation (AF) ablation. METHODS AND RESULTS: Consecutive patients who underwent catheter ablation of AF were prospectively enrolled from February 2012 to September 2013. At the end of the procedure, a temporary subcutaneous 'Figure-of-eight' suture technique was used to achieve haemostasis. Anticoagulation strategy evolved during the study. Initially, vitamin K antagonists (VKAs) were stopped and replaced by administration of low-molecular-weight heparin. It was subsequently decided to perform these procedures without stopping VKA. With the arrival of direct oral anticoagulants (DOACs), it was decided to miss the evening dose before the procedure. One hundred and twenty-four patients were included. Seventy-three per cent of patients were male, and the mean age was 58 ± 10 years old. One hundred and twelve patients (90%) experienced paroxysmal AF and were treated by cryotherapy with the use of a 15 Fr outer diameter Flexcath Advance sheath. The 'Figure-of-eight' suture technique was able to be performed in all patients and was sufficient in 114 patients. Mechanical external compression was required for 10 patients. Three patients developed a haematoma. The overall incidence of haematoma was therefore 2.4%. CONCLUSION: Figure-of-eight suture is a fast closure technique that can be used as an efficient alternative to usual compression methods to prevent bleeding during high-intensity anticoagulation and the use of large-diameter venous sheaths and multiple femoral venous accesses.

Automatic assessment of atrial pacing threshold in current medical practice.

AIMS: The aim of this study was to validate the ambulatory automatic atrial threshold monitoring algorithm by comparing the measurements assessed by the automatic system and those evaluated manually by the physician at discharge, 2- and 8-month follow-up sessions. METHODS AND RESULTS: This is an observational multicentric prospective study of 352 patients implanted with EnPulse(®) DR pacemakers. Mean age was 76.3 ± 9.4 years. Indications of pacing were atrio-ventricular block (AVB) (64%) and sinus dysfunction (SD) or brady-tachy syndrome (36%). The automatic atrial threshold monitoring function was maintained at nominal programming state with daily measurement scheduled at 1:00 am. Ambulatory automatic atrial threshold assessment was possible for 91.5% of patients at discharge, 97.3% at 2 months, and 95.7% at 8 months. Causes of the unsuccessful attempts to perform automatic atrial threshold were atrial arrhythmias or permanent atrial and ventricular pacing. Feasibility is significantly better for AVB indication than SD indication due to more frequent occurrence of atrial fibrillation (AF). At each stage, there is a strict correlation between the automatic measurements and those conducted manually by the physician with a P < 0.001. CONCLUSION: Feasibility of ambulatory automatic atrial threshold is good. Results of the study show excellent correlation between the two methods for atrial threshold: there is no statistical difference between manual and automatic measurements during follow-up.

Effect of a pacing mode preserving spontaneous AV conduction on ventricular pacing burden and atrial arrhythmias.

BACKGROUND: Using dual-chamber pacemakers with new algorithms: Manage Ventricular Pacing (MVP™), minimizes unnecessary ventricular pacing (VP). This function operates in AAI/R mode with backup VP during AV block. AIM: The aim of "Generation MVP" study was to assess the VP burden and atrial arrhythmias (AA) burden according to indication of pacing and MVP™ function programming of AdaptaDR implantable pacemaker (Medtronic Inc., Minneapolis, MN, USA). METHODS: The multicenter observational "Generation MVP" study included 220 patients aged 75.9 ± 11 years (men = 52%) implanted for sinus node dysfunction (SND; n = 115) or atrio-ventricular block (AVB; n = 105). Programming MVP function has been left to the physician's discretion. Percentage of VP and AA burden (percentage of time spent in AA) stored in memories were assessed at 2 and 10 months. RESULTS: 220 patients were followed at 2 months (174 MVP [On], 46 MVP [off]) and at 10 months (165 MVP [On], 55 MVP [off]). Median percentage of VP is significantly lower when MVP is programmed [On] versus [off] at 2 and 10 months follow-up for SND and AVB indications of pacing (P < 0.001). Finally, programming MVP function is performed at middle term (10 months) for 84% of patients with SND and 65% of patients with AVB: median percentage of VP is as low as 0.6% for patients with SND and 12% for patients with AVB versus 95% for SND and 99% for AVB when MVP function is programmed [off](P < 0.001). Median AA burden was significantly lower when MVP function was programmed [On] versus [off] at 2 months (8.7% vs 28%; P < 0.001) and 10 months (1% vs 22%; P < 0.001). CONCLUSION: In this study programming MVP function decreases percentage of VP at 2 and 10 months for patients paced for SND or AVB. Moreover median AA burden is reduced when MVP function was programmed [On] vs [off] at two follow-ups.

Dual balloon size strategy for cryoisolation of the pulmonary veins in patients with atrial fibrillation: comparison of 23 and 28mm diameter cryoballoons.

BACKGROUND: Systematic use of a 28mm balloon has been proposed for pulmonary vein cryoisolation in patients with atrial fibrillation. OBJECTIVE: To assess the results of a dual balloon size strategy using a 23 or 28mm cryoballoon catheter for pulmonary vein isolation. METHODS: A total of 118 patients (mean age 56 ± 10 years) with paroxysmal (n=85) or persistent atrial fibrillation (n=33) were enrolled. Patients with four pulmonary veins<20mm in diameter were isolated with a 23mm cryoballoon (n=29); patients with one pulmonary vein diameter ≥20mm were isolated with a 28mm cryoballoon (n=89). RESULTS: No significant difference in procedural variables was observed between the two groups. AF-free survival, after a mean follow-up of 19.9 ± 5 months, was similar in the two groups (69% vs 62%; p=0.57 and between patients with paroxysmal atrial fibrillation (68% vs 68%; p=0.91) or persistent AF (75% vs 48%; p=0.60). AF duration before the ablation procedure (p=0.005) was an independent predictor of AF recurrence. Phrenic nerve palsy rate was not statistically different in the two groups (4 [14%] vs 9 [10%]; p=0.73). The temperature in the right superior pulmonary vein (p=0.008) was an independent predictor of phrenic nerve palsy. Five patients developed left atrial flutter with the 28mm diameter balloon versus none with the 23mm balloon. CONCLUSIONS: A dual balloon size strategy was not associated with a lower AF-free survival or a higher procedure-related complication rate in patients in whom the 23mm balloon was used. Pulmonary vein isolation with a 23mm cryoballoon catheter appears to be an appropriate option in selected patients with small pulmonary vein diameters.

Normal pulmonary veins anatomy is associated with better AF-free survival after cryoablation as compared to atypical anatomy with common left pulmonary vein.

BACKGROUND: Pulmonary vein cryoablation (PVC) is a new approach in the treatment of recurrent atrial fibrillation (AF). Computed tomography (CT) can be used to evaluate the left atrium anatomy and PVs dimensions to facilitate the procedure. In radiofrequency procedures, some anatomic variants such as common left (CLPV) or right (CRPV) PV were reported as factors associated with technical procedure difficulties and potential long-term complications. We hypothesized that the absence of CLPV as determined by CT would predict better AF-free survival after PVC. METHODS AND RESULTS: We included 118 consecutive patients (mean age 56 ± 10 years; 77% males) with drug refractory paroxysmal (72%)/persistent (28%) AF, with more than 6 months follow-up, who underwent PVC. On CT scanning images performed within 1 month prior to ablation, we evaluated PV anatomic patterns: presence of CLPV or CRPV. Each patient was evaluated by 24-hour Holter monitoring within 1 and 3 months and all patients were periodically evaluated at 1, 3, and 6 months, and every 6 months thereafter. Patients were asked to record their 12-lead electrocardiogram whenever they experienced symptoms suggestive of AF. Recurrence was defined as AF that lasted at least 30 seconds. CLPV was present in 30 (25%) patients and no patients with CRPV were identified. At the end of the 13 months follow-up, patients with normal PVs had significantly better AF-free survival compared to patients with CLPV (67% vs 50%, P = 0.02). The difference was present in patients with paroxysmal AF (P = 0.008) but not in patients with persistent AF (P = 0.92). CONCLUSION: In patients undergoing cryoballoon PV isolation for AF, the presence of normal PVs pattern is associated with better AF-free survival as compared to atypical PV anatomy with CLPV, particularly in patients with paroxysmal AF.

Ajmaline challenge for the diagnosis of Brugada syndrome: which protocol?

BACKGROUND: Ajmaline challenge is commonly used for the diagnosis of Brugada syndrome. A slow infusion rate has been recommended in view of the proarrhythmic risk, but the diagnostic value of various infusion rates has not been investigated. AIMS: To compare rapid and slow ajmaline infusion rates and to assess the proarrhythmic risk. METHODS: The first part of this study prospectively compared rapid and slow infusion rates in terms of results and ventricular arrhythmias. Thirty-two patients (mean age 41±12 years; 26 men) received the two ajmaline challenges on different days. According to randomization, ajmaline (1 mg/kg) was infused at 1 mg/sec or over 10 minutes. The second part of the study retrospectively assessed the prevalence of ventricular arrhythmia during 386 challenges performed at a rapid infusion rate. RESULTS: No differences were observed between rapid and slow tests. All patients diagnosed as positive or negative with one test obtained the same result with the other test. Ventricular premature beats were observed in five of 32 patients during the slow challenge and in four of 32 patients during the rapid challenge. No sustained ventricular arrhythmias were observed. Analysis of the 386 tests revealed four episodes of ventricular arrhythmia (two complex ventricular premature beats, one non-sustained ventricular tachycardia and one ventricular fibrillation). CONCLUSION: Slow and rapid infusions of ajmaline have identical diagnostic performances on suspected Brugada electrocardiograms. Owing to the risk of severe proarrhythmia, a slow infusion rate, allowing early discontinuation, should be recommended.