Background
Time has been postulated as an important factor for electrical remodeling of the left atrium (LA) in persistent atrial fibrillation (AF) (‘AF begets AF’). However, it is still a matter of ...debate if structural changes are the cause or consequence of AF. We sought to determine the clinical and invasive parameters, which correlate with LA scar as determined by voltage mapping, in patients with persistent AF.
Methods
Seventy consecutive patients undergoing ablation of persistent (49%) or long-standing persistent AF (51%), between January 2013 and February 2014, were enrolled in the study. Besides clinical parameters, 2D echocardiographic assessment of LA size and LA pressure (LAP) after transseptal puncture was also considered. Bipolar endocardial signals with a mean voltage amplitude < 0.1 mV during AF were defined as LA scar.
Results
In the univariable analysis, LA scar was associated with age, gender, coronary artery disease (CAD), glomerular filtration rate (GFR), LA size and LAP. Arrhythmia duration, mild to moderate mitral regurgitation (MR), left ventricular dysfunction and left ventricular hypertrophy showed no significant correlation with atrial scar (all
p
> 0.05).
In a multivariable regression model, LA scar area was independently associated with age, female gender and LA area. AF duration was not associated with LA scar.
Conclusions
In this study, older age, greater LA area and female gender predicted the degree of LA scar, while other variables tested did not. In particular, we found no significant association between AF duration and LA scar.
Background
High-power short-duration (HPSD) radiofrequency ablation (RFA) is highly efficient and safe while reducing procedure and RF time in pulmonary vein isolation (PVI). The QDot™ catheter is a ...novel contact force ablation catheter that allows automated flow and power adjustments depending on the local tissue temperature to maintain a target temperature during 90 W/4 s lesions. We analysed intraprocedural data and periprocedural safety using the QDot-catheter in patients undergoing PVI for paroxysmal atrial fibrillation (PAF).
Methods
We included
n
= 48 patients undergoing PVI with the QDot-catheter with a temperature-controlled HPSD ablation mode with 90 W/4 s (TC-HPSD). If focal reconnection occurred besides repeat ablation, the ablation mode was changed to 50 W/15 s (QMode).
N
= 23 patients underwent cerebral MRI to detect silent cerebral lesions.
Results
Mean RF time was 8.1 ± 2.8 min, and procedure duration was 84.5 ± 30 min. The overall maximal measured catheter tip temperature was 52.0 °C ± 4.6 °C, mean overall applied current was 871 mA ± 44 mA and overall applied energy was 316 J ± 47 J. The mean local impedance drop was 12.1 ± 2.4 Ohms. During adenosine challenge,
n
= 14 (29%) patients showed dormant conduction. A total of
n
= 24 steam pops were detected in
n
= 18 patients (39.1%), while no pericardial tamponade occurred. No periprocedural thromboembolic complications occurred, while
n
= 4 patients (17.4%) showed silent cerebral lesion.
Conclusions
TC-HPSD ablation with 90 W/4 s using the QDot-catheter led to a reduction of procedure and RF time, while no major complications occurred. Despite optimized temperature control and power adjustment, steam pops occurred in a rather high number of patients, while none of them leads to tamponade or to clinical or neurological deficits.
The eradication of ventricular tachycardia (VT) isthmus sites constitutes the minimal procedural endpoint for VT ablation procedures. Contemporary high-resolution computed tomography (CT) imaging, in ...combination with computer-assisted analysis and segmentation of CT data, facilitates targeted elimination of VT isthmi. In this context, inHEART offers digitally rendered three-dimensional (3D) cardiac models which allow preoperative planning for VT ablations in ischemic and non-ischemic cardiomyopathies. To date, almost no data have been collected to compare the outcomes of VT ablations utilizing inHEART with those of traditional ablation approaches.
The presented data are derived from a retrospective analysis of n = 108 patients, with one cohort undergoing VT ablation aided by late-enhancement CT and subsequent analysis and segmentation by inHEART, while the other cohort received ablation through conventional methods like substrate mapping and activation mapping. The ablations were executed utilizing a 3D mapping system (Carto3), with the mapping generated via the CARTO® PENTARAY™ NAV catheter and subsequently merged with the inHEART model, if available.
Results showed more successful outcome of ablations for the inHEART group with lower VT recurrence (27% vs. 42%, p < 0.06). Subsequent analyses revealed that patients with ischemic cardiomyopathies appeared to derive a significant benefit from inHEART-assisted VT ablation procedures, with a higher rate of successful ablation (p = 0.05).
Our findings indicate that inHEART-guided ablation is associated with reduced VT recurrence compared to conventional procedures. This suggests that employing advanced imaging and computational modeling in VT ablation may be valuable for VT recurrences.
The modified anterior line (MAL) is an alternative to the mitral isthmus (MI) line for the treatment of perimitral atrial flutter (PMFL). We sought to investigate acute and long-term efficacy of this ...line if routinely used for PMFL.
The cohort included 77 consecutive patients who underwent catheter ablation of PMFL. The anterior line was deployed between the anterolateral mitral annulus and the ostium of the left superior pulmonary vein. Perimitral atrial flutter was either the presenting arrhythmia after persistent atrial fibrillation (AF) ablation (Group 1, n = 42, 54.5%), occurring during AF ablation (Group 2, n = 25, 35%) or presenting as primary arrhythmia (Group 3, n = 8, 10%). Acute success was defined as PMFL termination during MAL deployment with demonstration of bidirectional line block. Acute success was achieved in 68 of 77 patients (88%) without difference between the three groups. In five patients an additional MI line was necessary to terminate PMFL and in four patients both lines failed to achieve termination. During follow-up (16 ± 7 months), 38 of 77 (49%) patients underwent a repeat procedure for a recurrent arrhythmia. During reablation, 13 of 38 (34%) patients were identified to have a PMFL recurrence. Persistent MAL block was demonstrated in 22 of 38 (58%) patients during the repeat ablation.
The MAL is effective for acute and long-term treatment of PMFL. Maintenance of bidirectional MAL block was shown in 58% of patients during a repeat ablation.
Catheter Ablation for “Lone” Atrial Fibrillation
Background
Atrial fibrillation in otherwise healthy young patients has been termed “lone” atrial fibrillation (AF). The best treatment choice is still ...under discussion. The aim of this study was to report on efficacy and safety of catheter ablation.
Methods
Among 855 patients referred to our center between 2011 and 2013, 76 (9%) met the diagnostic criteria for lone AF (mean age 45 ± 8 years; mean LA diameter 37 ± 4 mm; paroxysmal AF 82%; persistent AF 18%). The primary endpoint was freedom from any atrial tachycardia after the first ablation; the secondary endpoint was freedom from any atrial tachycardia after the last ablation procedure without antiarrhythmic drugs.
Results
The primary endpoint occurred in 56 patients (74%) after a mean follow‐up time of 444 ± 344 days. The secondary endpoint occurred in 73 patients (96%) after a mean of 1.3 ablations/patient during a follow‐up time of 459 ± 366 days. The risk of AF recurrence was not influenced by AF duration or by the type of AF (paroxysmal versus persistent). In a multivariate regression analysis smoking (P = 0.001), first degree atrioventricular block (P = 0.001), and early (< 3 months) AF recurrence (P = 0.001) were independently associated with a higher risk of AF recurrence. Major peri‐procedural adverse events did not occur.
Conclusions
Catheter ablation in young healthy patients is highly effective and safe. The outcomes are maintained during long‐term follow‐up irrespective of preoperative AF duration. Patients with AF recurrence were more likely to smoke, have first degree AV block and early AF recurrence.
Rivaroxaban and Apixaban, increasingly used for stroke prevention in non-valvular atrial fibrillation (AF), might impact platelet reactivity directly or indirectly. By inhibition of Factor Xa (FXa) ...they preclude not only generation of relevant thrombin amounts but also block signalling of FXa via protease activated receptors. However, weather FXa-inhibition affects platelet haemostasis remains incompletely known. One hundred and twenty-eight patients with AF on chronic anticoagulation with either Rivaroxaban or Apixaban for at least 4 weeks were included in the study. In a time course group (25 on Rivaroxaban, 13 on Apixaban) venous blood samples were taken before NOAC medication intake in the morning as well as 2 and 6 h afterwards. In 90 patients (Rivaroxaban n = 73, Apixaban n = 17) blood samples were drawn during left atrial RFA procedures before as well as 10 and 60 min after the first heparin application (RFA group). Platelet reactivity analyzed by whole blood aggregometry (Multiplate Analyzer, Roche) in response to ADP, Collagen, TRAP and ASPI (arachidonic acid) was not altered by Rivaroxaban or Apixaban neither in the time course nor in the RFA group. Moreover, soluble P-selectin, Thrombospondin, von Willebrand Factor and beta thromboglobulin plasma levels, measured by ELISA, showed no statistically significant changes in both clinical settings for either FXa-inhibitor. The present study fails to demonstrate any significant changes on platelet reactivity in patients with AF under chronic Rivaroxaban or Apixaban medication, neither for trough or peak levels nor in case of a haemostatic activation in vivo as depicted by RFA procedures.
Purpose
Measuring the anticoagulant effect of heparin during radiofrequency ablation (RFA) in patients taking apixaban and rivaroxaban is challenging, since the activated coagulation time (ACT) does ...not seem to reflect the true anticoagulant activity of these drugs. We therefore evaluated coagulation properties of apixaban and rivaroxaban during RFA by different coagulation assays to better monitor periprocedural hemostasis.
Methods
The study included 90 patients (61 ± 12 years) with atrial fibrillation who underwent RFA procedures. Patients received 20 mg rivaroxaban (
n
= 73) once or 5 mg apixaban (
n
= 17) twice daily 4 weeks prior to the procedure. During RFA, unfractionated heparin i.v. was given to maintain an ACT of 250–300 s. Blood samples were taken before and 10, 60, and 360 min after heparin administration.
Results
Heparin displayed a lower anti-Xa activity in rivaroxaban-treated patients compared to apixaban-treated patients. In contrast, D-dimer and prothrombin fragment F1+2 plasma levels indicated a higher activation of the coagulation cascade in apixaban/heparin than in rivaroxaban/heparin patients. This discordant coagulative state measured
in vitro
had no clinical impact in terms of bleeding or thromboembolic complications.
Conclusion
We found different biochemical responses to rivaroxaban/heparin and apixaban/heparin during RFA. Precaution is necessary when monitoring periprocedural hemostasis in DOAC patients to avoid mismanagement.
Aims This is a prospective, randomized study comparing transvenous cryoablation with radiofrequency (RF) ablation of atrioventricular nodal re-entrant tachycardia (AVNRT). Methods and results In this ...pilot trial, 200 patients with AVNRT were randomized to undergo cryoablation or RF ablation of the slow pathway. A 7 Fr 4-mm-tip cryocatheter (Cryocath®) was used for cryomapping and cryoablation. Cryomapping was performed at the temperature of −30 °C to test the effect on the candidate ablation site. Following successful cryomapping, cryoablation was performed to produce an irreversible lesion by freezing to −75 °C. Procedural success, defined as elimination of the slow pathway or noninducibility of AVNRT, was achieved in 97/100 (97%) patients in the Cryo group vs. 98/100 (98%) patients in the RF group. No permanent complete AV-block occurred in either group. During a median of 246 days of follow-up, 8 patients in the Cryo group and 1 in the RF group had AVNRT recurrence. The cumulative incidence of primary endpoint (a combination of procedural failure, permanent complete AV-block and AVNRT recurrence) was significantly higher in the Cryo group than in the RF group (P=0.03, Log-rank test). Conclusions The results of this pilot study indicate that transvenous cryoablation using a 4-mm-tip cryocatheter is associated with a comparable acute success rate but a higher recurrence rate as compared with RF ablation in patients with AVNRT. Potential benefits of cryoablation for ablation of AVNRT need to be determined in a larger multi-centre trial.
Pulmonary vein (PV) reconduction after PV isolation (PVI) unmasked by adenosine is associated with a higher risk for paroxysmal atrial fibrillation (PAF) recurrence. It is unknown if the reconnected ...PVs after adenosine testing and immediate re-ablation can predict reconnection and reconnection patterns of PVs at repeat procedures. We assessed reconnection of PVs with and without dormant-conduction (DC) during the first and the repeat procedure.
We included 67 patients undergoing PVI for PAF and a second procedure for PAF recurrence. DC during adenosine administration at first procedure was seen in 31 patients (46%). 264 PVs were tested with adenosine; DC was found in 48 PVs (18%) and re-ablated during first procedure. During the second procedure, all PVs where checked for reconnection.
Fifty-eight patients (87%) showed PV reconnection during the second procedure. Reconnection was found in 152/264 PVs (58%). Of 216 PVs without reconnection during adenosine testing at the first ablation, 116 PVs (53.7%) showed reconnection at the repeat procedure. Overall, 14.9% of patients showed the same PV reconnection pattern in the first and second procedure, expected statistical probability of encountering the same reconnection pattern was only 6.6%(p = 0.012).
In repeat procedures PVs showed significantly more often the same reconnection pattern as during first procedure than statistically expected. More than 50% of initial isolated PVs without reconnection during adenosine testing showed a reconnection during repeat ablation. Techniques to detect susceptibility for PV re-connection like prolonged waiting-period should be applied. Elimination of DC should be expanded from segmental to circumferential re-isolation or vaster RF application.
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