Evaluation of troponin I serum levels in patients with arrhythmias with and without coronary artery disease.

BACKGROUND: Elevated levels of cardiac enzymes in the blood are an indicator of ongoing cardiac ischemia. Persistent tachycardia may lead to myocardial ischemia due to oxygen supply-demand mismatch. OBJECTIVES: We sought to evaluate the probability of underlying coronary artery disease (CAD) in patients with symptomatic supraventricular (SVT) or ventricular tachyarrhythmias (VT) based on cardiac enzyme level fluctuation. MATERIALS AND METHODS: Troponin I (TNI) levels were measured twice and coronary angiography was also performed in patients without a history of cardiovascular disease and symptomatic SVT or VT. RESULTS: Of the 114 (group A: CAD (n = 40), group B: no CAD (n = 74)) patients eligible for the study, 34 patients in group A and 64 patients in group B had SVT, while 6 patients in group A and 10 patients in group B had VT. All patients with underlying CAD developed a significantly elevated TNI level compared to baseline, irrespective of arrhythmia type (2.02 ± 7.98 ng/ml vs. 5.64 ± 13.38, p = 0.031). In patients without CAD, TNI level was not significantly elevated compared to the baseline level, irrespective of arrhythmia type (0.34 ± 1.38 ng/ml vs. 0.48 ± 1.48 ng/ml, p = 0.158). Most patients with normal TNI levels (46 of 47 patients; 98 %) had SVT. CAD was present in 13 of 47 patients (27 %) with tachycardia, despite normal TNI levels. CONCLUSIONS: Elevated TNI levels are not helpful to discriminate between SVT and VT. An increase in TNI level in repeated blood sampling can help identify patients with higher probability of underlying CAD. Patients with VT demonstrated higher increases in TNI levels, compared to patients with SVT.

Uninterrupted use of direct oral anticoagulants versus vitamin K antagonists for catheter ablation of atrial fibrillation with PVAC gold: incidence of silent cerebral microembolic events.

BACKGROUND: Silent cerebral microembolic events (SCE) after duty-cycled ablation of atrial fibrillation using PVAC have been detected by cerebral magnet resonance imaging (MRI) in a substantial number of patients. The purpose of this study was to investigate if uninterrupted oral anticoagulation with non-vitamin K antagonists (NOACs) compared with vitamin K antagonists (VKA) affects the incidence of SCE after pulmonary vein isolation (PVI) using PVAC Gold. METHODS: Eighty-four consecutive patients (62 ± 15 years, 58% male) undergoing a first PVI were prospectively enrolled. Of these, 42 were on VKA and 42 on uninterrupted NOAC treatment. An activated clotting time (ACT) ≥ 350 s was targeted for ablation. RESULTS: Cerebral MRI the day after PVI revealed acute diffusion-weighted positive lesions in 11/42 (26%) VKA compared with 14/42 (33%) in NOAC patients (p = 0.634). No differences were found for lesion size, number of lesions/patient, and number of lesions indicating cerebral infarction (2.4% for VKA and 4.8% for NOAC patients). Seventy-five percent of NOAC patients with sporadic ACT levels < 300 s during PVI developed SCE compared with 22% of corresponding VKA patients (p = 0.030). VKA and NOAC subgroups with ACT ≥ 350 s had no reduced incidence of SCE compared with ACT 300-350 s. CONCLUSIONS: A significant, but comparable, number of patients under uninterrupted anticoagulation with VKA or NOACs still experience SCE after PVAC Gold PVI. NOAC patients with sporadic subtherapeutic ACT levels during PVI are at the highest risk for SCE while permanent ACT levels ≥ 350 s did not further reduce the incidence of SCE in both groups.

Is the time of atrial fibrillation recurrence after cryoballoon ablation of paroxysmal atrial fibrillation influenced by the pattern of PV reconnections?

BACKGROUND: Pulmonary vein isolation (PVI) with 2nd-generation cryoballoon (CB) has been shown to be effective in the treatment of paroxysmal atrial fibrillation (AF). We describe pulmonary vein (PV) reconnection at repeat ablation in patients with AF recurrence after CB PVI and analyze the correlation between the time of AF recurrence and the observed PV reconnection patterns. METHODS: Sixty-six patients undergoing a redo PVI for recurrent AF were enrolled 9.1 ± 2.6 months after the initial CB PVI procedure. RESULTS: Ninety-two percent had PV reconnections with a mean of 1.97 ± 0.8 reconnected PVs/patient, and 52% of formerly isolated PVs were found reconnected. The highest reconnected rates were observed for left superior PVs (67%). Fifty-three percent of the patients had 2 reconnected PVs, no patient had all PVs reconnected, and 8% were without PV reconnection. There was a significant negative correlation between the time of AF recurrences and the extent of PV reconnections at redo PVI for patients with proven PV reconnection in more than one PV (R = 0.52, p < 0.001), while all patients without PV reconnection had AF recurrences within the first 9 months after PVI. CONCLUSIONS: At redo ablation, most patients with recurrence of AF after CB PVI had PV reconnection(s). Patients with PV reconnection(s) showed a negative correlation between the number of reconnected PVs and the time of AF recurrence with more extensive PV reconnections resulting in earlier PV recurrences after the blanking period. Patients without PV reconnection experienced early AF recurrences, indicating non-PV triggers contributing for paroxysmal AF recurrences in these patients.

Correlation of pulmonary vein reconnection patterns after cryoballoon and duty-cycled ablation of atrial fibrillation with the time of arrhythmia recurrence.

BACKGROUND: Pulmonary vein isolation (PVI) is safe and effective in the treatment of atrial fibrillation (AF). We compare and correlate pulmonary vein (PV) reconnection patterns at repeat ablation in patients with recurrent AF after PVI using duty-cycled radiofrequency (RF) technology (PVAC) or second-generation cryoballoon (CB) with the time of AF recurrence. METHODS AND RESULTS: In total, 85 PVAC and 66 CB patients undergoing a second ablation were enrolled 9.7 ± 3.4 months after initial PVI. PV reconnections were comparably high between both groups (93% PVAC and 92% CB patients). A mean of 2.79 ± 1.2 PVs/patient were reconnected after PVAC PVI compared with 1.97 ± 0.8 in CB patients, P < .0001. 33% PVAC patients, but no CB patient had 4 reconnected PVs (P < .0001). Early AF recurrences were more frequently observed in PVAC patients with ≥2 reconnected PVs, in CB patients with ≥3 reconnected PVs (both P < .01) and patients without PV reconnection, irrespective of the ablation technique. One reconnected PV was associated with late AF recurrence only in CB patients. The correlation between number of reconnected PVs and time of AF recurrence was -0.32 for PVAC and -0.52 for CB. CONCLUSIONS: CB PVI was associated with greater durability and lesser PV reconnections/patient. There were negative correlations for both devices between extent of PV reconnections and time of AF recurrence. CB patients with early AF recurrences- although less frequently observed compared with PVAC patients had more reconnected PVs than PVAC patients, suggesting additional effects for AF prevention after CB PVI.

A modified fluoroscopy protocol to minimize radiation exposure during pulmonary vein isolation with second-generation cryoballoon.

BACKGROUND: Pulmonary vein isolation (PVI) using second-generation cryoballoon (CB2) is considered to be safe and effective in the treatment of atrial fibrillation (AF). Reported radiation exposure during PVI with CB2 is higher if compared with other technologies. We investigated acute and mid-term effects of a modified fluoroscopy protocol to minimize radiation exposure during CB2 PVI with regard to safety and efficacy. METHODS: The study comprised 180 consecutive patients undergoing CB2 PVI. In the first 100 patients, PVI was performed using conventional fluoroscopy settings (group 1), while the following 80 patients (group 2) received PVI with a modified protocol. The protocol consisted of (a) general reduction of fluoroscopy frame rate to 3/s, (b) avoidance of cine runs and selective PV angiograms, and (c) enhanced radiation awareness. Retrospective data analysis was performed in respect to dose area product (DAP), fluoroscopy time, and freedom from AF during a 12-month follow-up. RESULTS: Group 2 patients had lower DAP (426 ± 433 vs 3334 ± 2271 cGycm2 ), fluoroscopy time (13.8 ± 6.3 vs 16.7 ± 5.6 minutes), LA dwell time (49.3 ± 15.5 vs 61.6 ± 16.2 minutes), and procedure time (85.5 ± 22.9 vs 94.9 ± 23.6 minutes); P < .01 for all. One-year freedom from AF was comparable between both groups (71% group 1 vs 73% group 2, ns). CONCLUSION: Radiation exposure and procedure time during CB2 PVI can be significantly reduced by using a modified fluoroscopy protocol and increased radiation awareness without compromising acute and 1-year freedom from AF if performed by experienced operators.

Is the Time of Atrial Fibrillation Recurrence After Duty-Cycled Radiofrequency Ablation Affected by the Pattern of Pulmonary Vein Reconnections?

BACKGROUND: Pulmonary vein isolation (PVI) with multielectrode duty-cycled radiofrequency (PVAC) has been shown to be effective in the treatment of atrial fibrillation (AF). We describe pulmonary vein (PV) reconnection at repeat ablation in patients with AF recurrence after PVAC PVI and analyze the correlation between the time of AF recurrence and the observed PV reconnection patterns. METHODS: Eighty-five patients undergoing a redo PVI for recurrent AF 9.2 ± 3.8 months after an initial PVAC PVI procedure was retrospectively enrolled. RESULTS: A total of 93% had PV reconnections with a mean of 2.97 ± 1.2 reconnected PVs/patients and 75% of formerly isolated PVs were found reconnected. The highest reconnection rates (94%) were observed for left common trunks (CTs). A total of 33% patients had three and four reconnected PVs, respectively, while 7% were without PV reconnection. There was a moderate but significant negative correlation between the time of AF recurrences and the extending of PV reconnections at redo PVI for patients with proven PV reconnection (r = -0.32, P = 0.005), whereas five out of six patients without PV reconnection had recurrences within the first 9 months after PVI. CONCLUSIONS: At redo ablation most patients with recurrence of AF after PVAC PVI had PV reconnection(s). Patients with PV reconnection(s) showed a moderate negative correlation between the number of reconnected PVs and the time of AF recurrence with more extensive PV reconnections resulting in earlier PV recurrences after the blanking period. Patients without PV reconnection experienced early AF recurrences, indicating non-PV triggers contribute to AF recurrences in these patients.

Comparison of pulmonary vein reconnection patterns after multielectrode phased radiofrequency- and cryoballoon ablation of atrial fibrillation.

BACKGROUND: Pulmonary vein isolation (PVI) using phased radiofrequency (RF) energy has been shown to be effective in the treatment of atrial fibrillation (AF). METHODS: We characterize and compare pulmonary vein (PV) reconnection at repeat ablation in patients with AF after initially successful PVI using phased RF technology (PVAC) or 2nd generation cryoballoon (CB). Eighty five patients undergoing redo PVI using multielectrode PVAC phased RF catheter and 66 patients after CB PVI were enrolled 9.7 ± 3.4 months after the initial ablation procedure. RESULTS: The percentage of patients with PV reconnection(s) was comparably high between both groups (93% PVAC and 92% CB). However, 75% of all PVs and left common trunks (CTs) isolated with PVAC were reconnected, compared with 52% reconnections after CB PVI (p < 0.001). A mean of 2.79 ± 1.2 PVs and CTs/patient were reconnected after PVAC PVI compared with 1.97 ± 0.8 in CB patients, p < 0.0001. No patients in the CB group had 4 reconnected PVs, while this pattern of reconnection was observed in 33% in the PVAC group (p < 0.0001). The percentage of patients in the PVAC group with ≥3 reconnected PVs was significantly higher compared with CB patients (56 patients (66%) vs. 17 patients (26%), p < 0.0001), while the percentage of patients with no PV reconnection was comparably low in PVAC and CB patients (7 and 8%, respectively). CTs were most frequently reconnected after PVAC PVI (94%) and left superior PVs after CB ablation (67%), respectively. CONCLUSIONS: The number of patients with recurrent AF and PV reconnection(s) at redo PVI was comparably high between both groups. However, the extent and distribution of PV reconnections was different in many aspects, indicating more stable atrial lesions after CB PVI compared with PVAC technology.

A subvalvular catheter approach for radiofrequency ablation of right-sided accessory pathways.

BACKGROUND: Conventional catheter ablation of right-sided accessory pathways (RAPs) can be challenging. OBJECTIVE: To determine if a subvalvular catheter approach for RAPs targeting the ventricular insertion site, as on the left side, can improve catheter stability and tissue contact and thus increase acute and chronic ablation success rates. METHODS AND RESULTS: We retrospectively compared 22 patients (pts) with conventional catheter ablation of RAPs (group 1) with 9 consecutive pts (group 2) undergoing catheter ablation of a RAP using a subvalvular catheter approach targeting the ventricular site of AP. Ablation failed in 2/22 group 1 vs 0/9 group 2 pts (ns) and recurrences of AP conduction were registered in 4/19 group 1 vs 1/9 group 2 pts (ns) during follow-up. Significant shorter values were found in group 2 pts compared with group 1 for number of RF applications (3.6 ± 1.6 vs 8.2 ± 4.3), AP block time (6.2 ± 2.4 vs 9.2 ± 3.9 min), fluoroscopy time (17.2 ± 6.9 vs 25.6 ± 10.3 min), and procedure time (70.8 ± 23.9 vs 138 ± 44.4 min). There were no procedure related complications. CONCLUSION: Catheter ablation of RAPs using a subvalvular approach seems as effective and safe compared with conventional ablation but with reduced procedure time and radiation exposure and might be at least considered an alternative after failed conventional catheter ablation of RAPs.

Incidence of early pulmonary vein reconnections using different energy sources for pulmonary vein isolation: Multielectrode phased radiofrequency vs second-generation cryoballoon.

OBJECTIVE: To determine and compare the incidence of early recurrence of conduction after pulmonary vein isolation (PVI) using two different ablation technologies: phased radiofrequency by a multipolar ablation catheter (PVAC) and cryo-ablation by a second-generation cryoballoon (CB). METHODS AND RESULTS: Two hundred patients (pts) with atrial fibrillation underwent PVI with PVAC (Group 1) or CB (Group 2), with 100 pts in each group. The incidence of PV reconnection (PVR) for each vein was examined in both groups at least 30 minutes after successful PVI. There were no significant clinical differences between both groups. Total procedure-, fluoroscopy-, and left atrial (LA) dwell time were significantly shorter in Group 2 pts (P < .0001). Early PVR was recorded in 69/388 (18%) isolated PVs or left common trunks (CTs) in Group 1 compared with 25/386 (7%) in Group 2 (P < .0001). Forty-three pts in Group1 were found to have PVR compared with 22 pts in Group 2 (P = .0015). Group 1 pts with CTs showed significantly more PVR than pts of Group 2 (P = .047). In both groups, CTs and CT branches were found to reconnect significantly more frequent compared with all other veins. CONCLUSION: Both PVAC and CB are effective to achieve PVI. Early PVR is observed with the significantly lower frequency with second-generation CB compared with PVAC, contributing to shorter procedure-, fluoroscopy, and LA dwell times. CTs and CT branches exhibit the highest incidence of PVR for both devices.

MRI-detected brain lesions in AF patients without further stroke risk factors undergoing ablation - a retrospective analysis of prospective studies.

BACKGROUND: Atrial fibrillation (AF) without other stroke risk factors is assumed to have a low annual stroke risk comparable to patients without AF. Therefore, current clinical guidelines do not recommend oral anticoagulation for stroke prevention of AF in patients without stroke risk factors. We analyzed brain magnetic resonance imaging (MRI) imaging to estimate the rate of clinically inapparent ("silent") ischemic brain lesions in these patients. METHODS: We pooled individual patient-level data from three prospective studies comprising stroke-free patients with symptomatic AF. All study patients underwent brain MRI within 24-48 h before planned left atrial catheter ablation. MRIs were analyzed by a neuroradiologist blinded to clinical data. RESULTS: In total, 175 patients (median age 60 (IQR 54-67) years, 32% female, median CHA2DS2-VASc = 1 (IQR 0-2), 33% persistent AF) were included. In AF patients without or with at least one stroke risk factor, at least one silent ischemic brain lesion was observed in 4 (8%) out of 48 and 10 (8%) out of 127 patients, respectively (p > 0.99). Presence of silent ischemic brain lesions was related to age (p = 0.03) but not to AF pattern (p = 0.77). At least one cerebral microbleed was detected in 5 (13%) out of 30 AF patients without stroke risk factors and 25 (25%) out of 108 AF patients with stroke risk factors (p = 0.2). Presence of cerebral microbleeds was related to male sex (p = 0.04) or peripheral artery occlusive disease (p = 0.03). CONCLUSION: In patients with symptomatic AF scheduled for ablation, brain MRI detected silent ischemic brain lesions in approximately one in 12 patients, and microbleeds in one in 5 patients. The prevalence of silent ischemic brain lesions did not differ in AF patients with or without further stroke risk factors.

Non-contact mapping in cardiac electrophysiology.

Catheter ablation of atrial and ventricular arrhythmias is now considered a standard technology for selected patients. In some patients, however, cure of the arrhythmia is hampered by the complexity of the arrhythmia or the way the arrhythmia presents in the electrophysiological laboratory: some focal atrial and ventricular arrhythmias are difficult to induce using electrical stimulation or medical provocation. Precise mapping of these arrhythmias is challenging or even impossible by contact mapping, while other arrhythmias are poorly tolerated and need early termination.In these scenarios, use of non-contact mapping technology can be an alternative to conventional mapping, since isopotential maps may require no more than one ectopic beat identical with the clinical focal arrhythmia to reconstruct its endocardial origin. This review article presents the technology of non-contact cardiac mapping, as well as various arrhythmias that have been successfully treated using this technology in the past. The possibilities and limitations of using non-contact cardiac mapping under various conditions are also presented.

Transient Elimination of Posterior Right Ventricular Outflow Tract Ectopy by Sternal Pressure.

BACKGROUND: Ventricular ectopy (VE) originating in the right ventricular outflow tract (RVOT) is a common arrhythmia. Mechanisms triggering or eliminating VE from RVOT are not entirely understood. METHODS AND RESULTS: A patient with frequent, symptomatic VE underwent an electrophysiologic study: VE origin was mapped by NavX 3D navigation (St. Jude Medical, Inc., St. Paul, MN, USA). Incidental pressure applied manually to the sternum reproducibly eliminated VE for the time of exposure. Radiofrequency-ablation was successfully performed in the posterior RVOT. CONCLUSION: The mechanism resulting in VE suppression remains speculative, since a mechanical alteration of the substrate for VE in the posterior RVOT by sternal pressure seems unlikely. "Mechano-electrical feedback" might have been the mechanism operative in this case.

Low rate of asymptomatic cerebral embolism and improved procedural efficiency with the novel pulmonary vein ablation catheter GOLD: results of the PRECISION GOLD trial.

AIMS: This prospective, multicentre study (PRECISION GOLD) evaluated the incidence of asymptomatic cerebral embolism (ACE) after pulmonary vein isolation (PVI) using a new gold multi-electrode radiofrequency (RF) ablation catheter, pulmonary vein ablation catheter (PVAC) GOLD. Also, procedural efficiency of PVAC GOLD was compared with ERACE. The ERACE study demonstrated that a low incidence of ACE can be achieved with a platinum multi-electrode RF catheter (PVAC) combined with procedural manoeuvres to reduce emboli. METHODS AND RESULTS: A total of 51 patients with paroxysmal atrial fibrillation (AF) (age 57 ± 9 years, CHA2DS2-VASc score 1.4 ± 1.4) underwent AF ablation with PVAC GOLD. Continuous oral anticoagulation using vitamin K antagonists, submerged catheter introduction, and heparinization (ACT ≥ 350 s prior to ablation) were applied. Cerebral magnetic resonance imaging (MRI) scans were performed within 48 h before and 16-72 h post-ablation. Cognitive function assessed by the Mini-Mental State Exam at baseline and 30 days post-ablation. New post-procedural ACE occurred in only 1 of 48 patients (2.1%) and was not detectable on MRI after 30 days. The average number of RF applications per patient to achieve PVI was lower in PRECISION GOLD (20.3 ± 10.0) than in ERACE (28.8 ± 16.1; P = 0.001). Further, PVAC GOLD ablations resulted in significantly fewer low-power (<3 W) ablations (15 vs. 23%, 5 vs. 10% and 2 vs. 7% in 4:1, 2:1, and 1:1 bipolar:unipolar energy modes, respectively). Mini-Mental State Exam was unchanged in all patients. CONCLUSION: Atrial fibrillation ablation with PVAC GOLD in combination with established embolic lowering manoeuvres results in a low incidence of ACE. Pulmonary vein ablation catheter GOLD demonstrates improved biophysical efficiency compared with platinum PVAC. TRIAL REGISTRATION: ClinicalTrials.gov NCT01767558.

Comparison of 'anatomically designed' and 'point-by-point' catheter ablations for human atrial fibrillation in terms of procedure timing and costs in German hospitals.

AIMS: The purpose of the FAST-PVI study was to compare 'traditional' ablation tools based on 'point-by-point' technology with the new 'anatomically designed' technologies in terms of procedure times and related costs for the treatment of paroxysmal atrial fibrillation. METHODS AND RESULTS: Four hundred and fifty-two consecutive ablation procedures (222 'anatomically designed', 136 Arctic Front® and 86 PVAC®) and 230 'point-by-point' ablations (100 CARTO XP and 130 NavX navigation systems) performed by nine university centres across Germany from 2006 to 2010 were evaluated retrospectively. Staffing and resources times for each procedure were documented together with patient morbidities, complications, and pulmonary veins isolations. On the basis of DRG data from 2006 to 2010, human resources use and equipment maintenance costs were assigned to ablation procedure and calendar year. All procedural times were significantly higher in 'point-by-point' technologies compared with 'anatomically designed' ablations [average lab occupancy time 185.30 vs. 280.28 min; physician time 152.21 vs. 238.04 min; support time 183.43 vs. 278.34 min and fluoroscopy time 29.11 vs. 40.72 min; P < 0.001 (95% confidence interval, CI)]. For each ablation procedure human resource use per operating minute resulted in lower costs for 'anatomically designed' ablations [€744.24 per patient; P < 0.001 (95% CI)]. Savings due to reduced duration in 'anatomically designed' technologies accrued to 20% lower human resource costs. Sensitivity analyses did not lead to any significant variations on the outcomes parameter cost per minute. CONCLUSION: FAST-PVI showed reductions in ablation procedural time may lead to increased hospital capacity and non-device-related cost-savings, while maintaining quality.

Complex atrial arrhythmias as first manifestation of catecholaminergic polymorphic ventricular tachycardia: an unusual course in a patient with a new mutation in ryanodine receptor type 2 gene.

Catecholaminergic polymorphic ventricular tachycardia is a rare life-threatening arrhythmogenic disorder. An association with paroxysmal atrial fibrillation and other atrial arrhythmias has been described, but in all published cases the initial manifestation of the disease was ventricular arrhythmia. This is the first report about a patient who presented with complex atrial tachycardia and sinus node dysfunction about 1 year before the typical ventricular arrhythmias were observed, leading to the diagnosis of catecholaminergic polymorphic ventricular tachycardia. In this girl, a mutation of the ryanodine receptor type 2 gene, which has not been described so far, was discovered.

Usefulness of N-acetylcysteine or ascorbic acid versus placebo to prevent contrast-induced acute kidney injury in patients undergoing elective cardiac catheterization: a single-center, prospective, randomized, double-blind, placebo-controlled trial.

BACKGROUND: Contrast-induced acute kidney injury (CI-AKI) is a serious complication of procedures requiring contrast media associated with rising costs, prolonged hospitalization, and increased mortality. The aim of this study was to assess whether prophylactic administration of standard dosages of intravenous N-acetylcysteine or ascorbic acid reduce the incidence of CI-AKI in patients with chronic renal insufficiency undergoing elective cardiac catheterization. METHODS: In a single-center, prospective, randomized, double-blind, placebo-controlled trial, the preventive effects of N-acetylcysteine and ascorbic acid were evaluated in 520 patients with chronically impaired renal function (serum creatinine ≥1.3 mg/dL) undergoing elective cardiac catheterization. The study drugs (600 mg N-acetylcysteine, 500 mg ascorbic acid, placebo) were administered intravenously twice (at 24 hours and 1 hour before the procedure). Serum creatinine, estimated glomerular filtration rate (eGFR) and serum urea were assessed at baseline and at 24 hours and 72 hours after contrast media exposure. CI-AKI was defined as a postangiographical increase in serum creatinine ≥0.5 mg/dL. Results. The incidence of CI-AKI was 27.6% in the N-acetylcysteine group (P=.20 vs placebo group) and in 24.5% in the ascorbic acid group (P=.11 vs placebo group). CI-AKI occurred in 32.1% of the placebo group. CONCLUSIONS: Standard doses of N-acetylcysteine and ascorbic acid did not prevent CI-AKI in patients at high risk undergoing cardiac catheterization with non-ionic, low-osmolality contrast agent.

Right atrial tachycardias related to regions of low-voltage myocardium in patients without prior cardiac surgery: catheter ablation and follow-up results.

AIMS: There are only few descriptions of patients without prior cardiac surgery in whom a large low-voltage zone (LVZ) or scar is the electrophysiological substrate for various atrial tachycardias. We describe the electrophysiological and electroanatomic characteristics of unusual macroreentrant atrial tachycardias (MRATs) in seven patients with spontaneous right atrial (RA) scarring and present long-term follow-up results. METHODS AND RESULTS: In 7 of 326 patients with MRAT treated with radiofrequency ablation we detected regions of RA spontaneous LVZ or scarring during conventional mapping of the arrhythmia. They underwent electroanatomic mapping and catheter ablation of the spontaneous and further induced arrhythmias with a long-term follow-up. A total of 17 different atrial tachycardias were observed with typical atrial flutter in four patients. In five patients a LVZ was found in the RA free wall and two patients had a septal scar. Stable circuits were around the scar or LVZ in four patients and through a 'channel' within the scar in two. Radiofrequency ablation sites included the cavotricuspid isthmus for typical atrial flutter, between the inferior vena cava and scar, a channel in the scar or the left atrial (LA) mitral isthmus. During follow-up of 34 ± 5 months, four patients were free from atrial tachycardias. Both patients with a septal RA scar developed LA tachycardias, requiring further catheter ablation. One patient presented with a novel type of atypical scar-related RA flutter. CONCLUSION: Mapping and ablation of scar-related RA tachycardias is an effective treatment but does not preclude the development of further tachycardias, some of them arising from the LA during long-term follow-up.

Does the number of simultaneously activated electrodes during phased RF multielectrode ablation of atrial fibrillation influence the incidence of silent cerebral microembolism?

BACKGROUND: Asymptomatic cerebral embolus (ACE) detected by diffusion-weighted magnetic resonance imaging (DW-MRI) following atrial fibrillation (AF) ablation has been reported at varying rates with different ablation techniques. OBJECTIVE: To evaluate the incidence of ACE after phased radiofrequency ablation for AF with procedural modifications that potentially reduce the embolic load. METHODS: One hundred twenty consecutive patients with AF underwent MRI before ablation, 24 hours after ablation, and at 4-6 weeks. In all patients, simultaneous activation of pulmonary vein ablation catheter electrode pairs 1 and 5 was forbidden. While in 60 group 1 patients, a maximum of 4 electrode pairs could be activated at a time, and in 60 group 2 patients, ablation was limited to a maximum of 2 pairs. All patients were on uninterrupted phenprocoumon, with an attempted activated clotting time of >300 seconds during ablation. RESULTS: Both patient groups were comparable. A total of 28 DW-positive lesions were detected in 24 of 120 patients (20%). Seventeen group 1 patients (28.3%) were positive for new asymptomatic DW cerebral lesions compared with 7 group 2 patients (11.7%) (P = .039). During MRI follow-up, 3 patients (2.5%) were diagnosed with a small T2-positive asymptomatic glial scar. Procedure time was longer in group 2 patients than in group 1 patients (159 ± 39 vs 121 ± 15; P < .001). CONCLUSIONS: Limiting the number of simultaneously activated electrode pairs to 2 significantly reduces the rate of ACE in patients treated with a multielectrode duty-cycled phased radiofrequency catheter system for AF. This reduction corresponds with a significant prolongation of the total procedure time.

Pulmonary vein re-isolation for atrial fibrillation using duty-cycled phased radiofrequency ablation: safety and efficacy of a primary 2:1 bipolar/unipolar ablation mode.

PURPOSE: Pulmonary vein isolation (PVI) using phased radiofrequency (RF) energy has been shown to be effective in the treatment of paroxysmal atrial fibrillation (AF). We characterize pulmonary vein (PV) conduction at repeat ablation in patients with AF after an initial successful PVI using phased RF technology and analyze the effects of a primary 2:1 ablation mode. METHODS AND RESULTS: A primary 4:1 bipolar/unipolar mode in group A patients (n = 22) was compared with a primary 2:1 mode in group B (n = 22) acutely and during follow-up. Of all PVs, 81 % showed reconnection(s); 52 % of them had reconnected in all PVs. PVI was achieved in all patients without complications. Procedure and fluoroscopy times were shorter in group B (108 ± 15 vs. 126 ± 24 min and 17 ± 5 vs. 23 ± 7 min, respectively). This was attributed to a significant decrease of early PV reconnections within the first 30 min in 17 % of group B patients vs. 45 % of group A patients (p < 0.001). After 9.5 ± 4 months, recurrence of AF was detected in 5 of 22 patients (22.7 %) in group A vs. 3 of 22 patients (13.6 %) in group B (p = 0.722). CONCLUSIONS: Phased RF energy applied by a 2:1 bipolar/unipolar mode seems safe and effective in redo-PVI procedures, resulting in a mid-term freedom from AF in 86.4%. Significant shorter procedure and fluoroscopy times compared with a primary 4:1 ablation mode during repeat PVI are mainly attributed to a lower incidence of acutely reconnected PVs within the first 30 min.