Incidence and patterns of atrial fibrillation after catheter ablation of typical atrial flutter-the FLUTFIB study.

AIMS: In patients with atrial flutter (AFL), ablation of the cavotricuspid isthmus (CTI) is a highly effective procedure to prevent AFL recurrence, but atrial fibrillation (AF) may occur during follow-up. The presented FLUTFIB study was designed to identify the exact incidence, duration, timely occurrence, and associated symptoms of AF after CTI ablation using continuous cardiac monitoring via implantable loop recorders. METHODS AND RESULTS: One hundred patients with AFL without prior AF diagnosis were included after CTI ablation (mean age 69.7 ± 9.7 years, 18% female) and received an implantable loop recorder for AF detection. After a median follow-up of 24 months 77 patients (77%) were diagnosed with AF episodes. Median time to first AF occurrence was 180 (43-298) days. Episodes lasted longer than 1 h in most patients (45/77, 58%). Forty patients (52%) had AF-associated symptoms.Patients with and without AF development showed similar baseline characteristics and neither HATCH- nor CHA2DS2-VASc scores were predictive of future AF episodes. Oral anticoagulation (OAC) was stopped during FU in 32 patients (32%) and was re-initiated after AF detection in 15 patients (15%). No strokes or transient ischaemic attack episodes were observed during follow-up. CONCLUSION: This study represents the largest investigation using implantable loop recorders (ILRs) to detect AF after AFL ablation and shows a high incidence of AF episodes, most of them being asymptomatic and lasting longer than 1 h. In anticipation of trials determining the duration of AF episodes that should trigger OAC initiation, these results will help to guide anticoagulation management after CTI ablation.

Risk of occurrence of electromagnetic interference from the application of transcutaneous electrical nerve stimulation on the sensing function of implantable defibrillators.

BACKGROUND: Transcutaneous electrical nerve stimulation (TENS) is an established method for pain relief. But electrical TENS currents are also a source of electromagnetic interference (EMI). Thus, TENS is considered to be contraindicated in implantable cardioverter-defibrillator (ICD) patients. However, data might be outdated due to considerable advances in ICD and cardiac resynchronization therapy (CRT) filtering and noise protection algorithm technologies. The aim of this pilot safety study was to re-evaluate the safety of TENS in patients with modern ICDs. METHODS AND RESULTS: One hundred and seven patients equipped with 55 different models of ICD/CRT with defibrillators from 4 manufacturers underwent a standardized test protocol including TENS at the cervical spine and the thorax, at 2 stimulation modes-high-frequency TENS (80 Hz) and burst-mode TENS (2 Hz). Potential interference monitoring included continuous documentation of ECG Lead II, intracardiac electrograms and the marker channel. Electromagnetic interference was detected in 17 of 107 patients (15.9%). Most frequent were: interpretations as a premature ventricular beats (VS/S) in 15 patients (14%), noise reversion in 5 (4.6%) which resulted in temporary asynchronous pacing in 3 (2.8%), interpretation as ventricular tachycardia/ventricular fibrillation in 2 (1.9%), and premature atrial beat in 2 (1.9%) patients. Electromagnetic interference occurrence was influenced by position (chest, P < 0.01), higher current intensity (P < 0.01), and manufacturer (P = 0.012). CONCLUSION: Overall, only intermittent and minor EMI were detected. Prior to the use of TENS in patients with ICDs, they should undergo testing under the supervision of a cardiac device specialist.

P-wave detection performance of the BioMonitor III, Confirm Rx and Reveal Linq implantable loop recorders.

INTRODUCTION: Rhythm interpretation of EGMs recorded by implantable loop recorders (ILRs) is facilitated in cases when p-waves are visible. The three most commonly used ILRs (BioMonitor III, Confirm RX and Reveal Linq) vary in size, electrode placement and filter algorithms. Therefore, p-wave visibility and amplitude on EGM may vary according to the implanted device. MATERIAL AND METHODS: Consecutive patients were included after ILR implantation. P-wave visibility and amplitude were evaluated in sinus rhythm on 30-s EGMs with standard resolution (25 mm/mV for Biotronik and St. Jude, 30 mm/mV for Medtronic) and after maximum magnification. Additionally, baseline characteristics and p-wave amplitude in lead II on the surface-ECG were documented. RESULTS: 148 patients with either BioMonitor III (n = 48), Confirm Rx (n = 51) or Reveal Linq (n = 49) ILRs were included. With standard resolution, p-waves were visible in 40 patients (83%) implanted with BioMonitor III, 36 patients (71%) with Confirm Rx and in 35 patients (71%) with Reveal Linq ILRs (p = 0.267). After maximum magnification, p-waves could not be identified in 6 patients with Confirm Rx ILR (12%) and 1 patient in both BioMonitor III and Reveal Linq ILR (2%; p = 0.051). The Biomonitor III showed higher p-wave amplitudes compared to the Confirm Rx (0.050 mV (0.040-0.070) vs. 0.030 mV (0.020-0.040); p < 0.001) and the Reveal Linq ILR (0.050 mV (0.040-0.070) vs. 0.030 mV (0.020-0.040); p < 0.001). CONCLUSION: P-wave amplitudes were higher in patients with Biomonitor III. This did not lead to higher p-wave visibility compared to the Confirm RX ILR or the Reveal Linq ILR.

Safe procedures despite ultra low radiation doses during catheter ablations of atrial and ventricular arrhythmias-A multicenter experience.

INTRODUCTION: Despite the development of non-fluoroscopic catheter visualization options, fluoroscopy is still used in most ablation procedures. The aim of this multicenter study was to evaluate the safety and efficacy of a new ultra-low dose radiation protocol for EP procedures in a large number of patients. METHODS AND RESULTS: A total of 3462 consecutive patients (male 1926 (55.6%), age 64.4 ± 14.0 years, BMI 26.65 ± 4.70) undergoing radiofrequency ablation (left atrial (n = 2316 [66.9%], right atrial (n = 675 [19.5%], or ventricular (n = 471 [13.6%]) in three German centers were included in the analysis. Procedures were performed using a new ultra-low dose protocol operating at 8nGy for fluoroscopy and 36nGy for cine-loops. Additionally a very low framerate (2-3FPS) was used. Using the new protocol very low Air kerma-area product (KAP) values were achieved for left atrial ablations (104.25 ± 84.22 µGym2 ), right atrial ablations (70.98 ± 94.79 µGym2 ) and ablations for ventricular tachycardias or PVCs (78.62 ± 66.59 µGym2 ). Acute procedural success was achieved in 3289/3388 (97.1%) while the rate of major complications was very low compared to previously published studies not using low dose settings (n = 20, 0.6%). CONCLUSION: The ultra-low dose, low framerate protocol leads to very low radiation doses for all EP procedures while neither procedural time, fluoroscopy time nor success or complication rates were compromised. When compared to current real-world Air KAP data the new ultra-low dose fluoroscopy protocol reduces radiation exposure by more than 90%.

Cardiac arrhythmias in patients with COVID-19: Lessons from 2300 telemetric monitoring days on the intensive care unit.

BACKGROUND: Patients with COVID-19 seem to be prone to the development of arrhythmias. The objective of this trial was to determine the characteristics, clinical significance and therapeutic consequences of these arrhythmias in COVID-19 patients requiring intensive care unit (ICU) treatment. METHODS AND RESULTS: A total of 113 consecutive patients (mean age 64.1 ± 14.3 years, 30 (26.5%) female) with positive PCR testing for SARS-CoV2 as well as radiographically confirmed pulmonary involvement admitted to the ICU from March to May 2020 were included and observed for a cumulative time of 2321 days. Fifty episodes of sustained atrial tachycardias, five episodes of sustained ventricular arrhythmias and thirty bradycardic events were documented. Sustained new onset atrial arrhythmias were associated with hemodynamic deterioration in 13 cases (35.1%). Patients with new onset atrial arrhythmias were older, showed higher levels of Hs-Troponin and NT-proBNP, and a more severe course of disease. The 5 ventricular arrhythmias (two ventricular tachycardias, two episodes of ventricular fibrillation, and one torsade de pointes tachycardia) were observed in 4 patients. All episodes could be terminated by immediate defibrillation/cardioversion. Five bradycardic events were associated with hemodynamic deterioration. Precipitating factors could be identified in 19 of 30 episodes (63.3%), no patient required cardiac pacing. Baseline characteristics were not significantly different between patients with or without bradycardic events. CONCLUSION: Relevant arrhythmias are common in severely ill ICU patients with COVID-19. They are associated with worse courses of disease and require specific treatment. This makes daily close monitoring of telemetric data mandatory in this patient group.

Reduction of mapping time in pulmonary vein isolation using atrial pacing during left atrial voltage map acquisition.

INTRODUCTION: 3D mapping systems are used during radiofrequency (RF) pulmonary vein isolation (PVI) to facilitate catheter navigation and to provide additional electroanatomical information as a surrogate marker for the presence and location of fibrotic atrial myocardium. Electric voltage information can only be measured when the myocardium is depolarized. Low heart rates or frequent premature atrial beats can significantly prolong creation of detailed left atrial voltage maps. This study was designed to evaluate the potential advantage of voltage information collection during atrial pacing instead of acquisition during sinus rhythm. METHODS AND RESULTS: A total of 40 patients were included in the study, in 20 consecutive patients voltage mapping was performed during sinus rhythm, and in the following 20 patients during atrial pacing. The average age of the included patients was 69.5 ± 9.4, 17 of 40 patients (43%) were male. All procedures were performed using the Carto 3D Mapping system. For LA voltage mapping, a multipolar circular mapping catheter was used. The atrium was paced via the proximal coronary sinus catheter electrodes with a fixed cycle length of 600 ms. By mapping during atrial pacing mapping time was reduced by 35% (441 s. (±141) vs. 683 s. (±203) p = 0.029) while a higher number of total mapping points were acquired (908 ± 560 vs. 581 ± 150, p = 0.008). CONCLUSION: Acquiring left atrial low voltage maps during atrial pacing significantly reduces mapping time. As pacing also improves comparability of left atrial electroanatomical maps we suggest that this approach may be considered as a standard during these procedures.

Cardiac Implantable Electronic Device Interrogation at Forensic Autopsy: An Underestimated Resource?

BACKGROUND: Postmortem interrogations of cardiac implantable electronic devices (CIEDs), recommended at autopsy in suspected cases of sudden cardiac death, are rarely performed, and data on systematic postmortem CIED analysis in the forensic pathology are missing. The aim of the study was to determine whether nonselective postmortem CIED interrogations and data analysis are useful to the forensic pathologist to determine the cause, mechanism, and time of death and to detect potential CIED-related safety issues. METHODS: From February 2012 to April 2017, all autopsy subjects in the department of forensic medicine at the University Hospital Charité who had a CIED underwent device removal and interrogation. Over the study period, 5368 autopsies were performed. One hundred fifty subjects had in total 151 CIEDs, including 109 pacemakers, 35 defibrillators, and 7 implantable loop recorders. RESULTS: In 40 cases (26.7%) time of death and in 51 cases (34.0%) cause of death could not be determined by forensic autopsy. Of these, CIED interrogation facilitated the determination of time of death in 70.0% of the cases and clarified the cause of death in 60.8%. Device concerns were identified in 9 cases (6.0%), including 3 hardware, 4 programming, and 2 algorithm issues. One CIED was submitted to the manufacturer for a detailed technical analysis. CONCLUSIONS: Our data demonstrate the necessity of systematic postmortem CIED interrogation in forensic medicine to determine the cause and timing of death more accurately. In addition, CIED analysis is an important tool to detect potential CIED-related safety issues.

Correlation of P-wave properties with the size of left atrial low voltage areas in patients with atrial fibrillation.

BACKGROUND: Left atrial low voltage areas (LVA) are associated with increased recurrence rates of atrial fibrillation (AF) after catheter ablation and can be a potential ablation target during the procedure. Therefore, noninvasive prediction of the presence and the distribution of LVA may help physicians to predict ablation outcomes and to guide antiarrhythmic management. MATERIAL AND METHODS: Seventy-three consecutive patients with atrial fibrillation undergoing first time left atrial ablation for paroxysmal or persistent AF were enrolled. P-wave properties (amplitude and duration) were measured in all limb and precordial leads in pre-interventional sinus rhythm surface ECGs and correlated with total LVA size. LVA were detected via high density low voltage maps of the left atrium in sinus rhythm. LVA were then manually encircled, their total size was calculated and given as a percentage of the total LA surface area. RESULTS: A significant, inverse correlation with LVA size was shown for P-wave amplitude for leads I, II, aVR, aVF, V1, V4, V5 and V6. Additionally, a significant positive correlation between LVA size and P-wave duration was shown for leads V1, V2 and V3. As the strongest correlation was shown for the amplitude in lead I (R = -0.578), this lead was used to find a potential cutoff for LVA prediction. The best cut-off for a P-wave amplitude in lead I to predict severe scarring (defined as LVA size >35%, according to UTAH stadium IV) was 0.062 mV with an area-under-the receiver-operating-characteristic curve of 0.935, a sensitivity of 85% and a specificity of 88%. CONCLUSIONS: P-wave duration and amplitude show significant correlations with LVA size and may be used as a noninvasive tool to predict severe scarring. Amplitudes in lead I smaller than 0.062 mV were found to be predictive of LVA >35%.

Pushing the limits: establishing an ultra-low framerate and antiscatter grid-less radiation protocol for left atrial ablations.

Aims: Despite the use of 3D mapping systems and new developments of non-fluoroscopic options, most centres still rely at least in part on fluoroscopy for catheter visualization during catheter ablations. The purpose of this study was to assess the feasibility of using an ultra-low frame rate and antiscatter grid-less radiation protocol during complex left atrial ablations to minimize radiation exposure for the patient and staff. Methods and results: A total of 150 consecutive patients undergoing left atrial ablations in our hospital were included in the analysis. The procedures were performed between January 2015 and November 2016. Of the included patients 75 (50%) underwent ablation before and 75 (50%) after the ultra-low frame rate (reduced from 4 to 2 FPS) and antiscatter grid-less radiation protocol was established. Procedures performed after the dose reduction protocol was established showed a 64% reduction of the dose area product (630.28 ± 550.96 vs. 226.44 ± 277.44 µGym2, P < 0.001), while fluoroscopy duration (14.22 ± 4.47 vs. 13.62 ± 7.11 min, P = 0.066) and procedural duration (1:48 ± 0:28 vs. 1:53 ± 0:34 min, P = 0.525) were not prolonged. Acute procedural success was achieved in all procedures. Two complications occurred before and one complication after the protocol was established. During four procedures, operators decided to re-introduce the antiscatter grid. This was due to impaired visibility in morbidly obese patients (n = 2) or technically difficult transseptal puncture (n = 2). Conclusion: The use of an ultra low framerate and antiscatter grid-less radiation protocol effectively reduced radiation dose for complex left atrial ablation procedures and lead to very low average patient doses. Reduced image quality did not impair procedural and fluoroscopy duration or acute procedural success.

Effects of propofol on ventricular repolarization and incidence of malignant arrhythmias in adults.

BACKGROUND: Propofol is commonly used for procedural sedation in interventional electrophysiology. However, ventricular arrhythmias under Propofol have been reported. Our aim was to investigate ventricular repolarization and incidence of ventricular arrhythmias under Propofol infusion in adults with cardiac arrhythmias. METHODS: QRS, QTcB (Bazett), QTcFri (Fridericia), JTc, measurement of T peak to Tend time (Tp-e) at baseline and under Propofol infusion was performed in 235 patients. Screening for unexpected ventricular arrhythmias was performed in 1165 patients undergoing EP procedures under Propofol. RESULTS: A significant prolongation of Tp-e under Propofol infusion (79.7±17.3 vs. 86.4±22.5ms, p<0.001) and of QTcFri (429.3±35.8 vs. 435.5±36.5, p=0.033) was detected. No significant change of the QTcB interval, JTc interval or QRS duration was observed. One case (0.09%) of ventricular fibrillation during rapid ventricular pacing under Propofol occurred. CONCLUSION: Although transmural dispersion of ventricular repolarisation is increased under Propofol, incidence of malignant ventricular arrhythmias is low. For evaluation of QT interval under Propofol, Fridericia's correction formula should be used rather than Bazett's formula.

Does the extent of left atrial arrhythmogenic substrate depend on the electroanatomical mapping technique: impact of pulmonary vein mapping catheter vs. ablation catheter.

AIMS: In persistent atrial fibrillation (AF), left atrial low-voltage areas and complex fractionated atrial electrograms (CFAEs) have been thoroughly discussed as critical substrate points for AF perpetuation. Thus, in patients undergoing pulmonary vein isolation, these sites are often considered additional ablation targets. Currently, mapping techniques for these substrate indicators are still under discussion. The aim of this study was to evaluate the impact of different mapping catheters on the detection of low-voltage areas and CFAE. METHODS AND RESULTS: Two bipolar voltage maps and two CFAE left atrial maps were obtained each in 30 patients undergoing catheter ablation of AF using the following two different catheters: A four-pole ablation catheter (MAP, mapping and ablation catheter) (electrode size: tip: 4 mm, band: 1 mm; inter-electrode spacing: 0.5-5-2 mm) and a 10-pole circular pulmonary vein mapping catheter (CMC) (electrode size: 1 mm; inter-electrode spacing: 7-7-7 mm). Successively, low-voltage and CFAE area sizes were then compared between the two catheters. Areas with a bipolar voltage of <0.5 mV were significantly smaller when obtained with the CMC compared with the MAP (8.9 ± 8.9 vs. 17.4 ± 11.7 cm², P < 0.001). This was also significantly different for a bipolar voltage of <0.2 mV (2.3 ± 4.6 vs. 6.2 ± 9.6 cm², P < 0.001). Complex fractionated atrial electrogram area sizes were significantly larger when obtained with the CMC compared with the MAP group (14.6 ± 10.9 vs. 19.4 ± 9.4 cm², P = 0.011). CONCLUSION: Low-voltage and CFAE area size varies significantly between different mapping catheters. Mapping electrode settings have to be taken into consideration for the assessment of electroanatomical substrate of AF.

Safety and efficacy of applying a low-dose radiation fluoroscopy protocol in device implantations.

AIMS: For cardiac implantable electronic device (CIED) implantations, visualization of lead placement is necessary and fluoroscopy remains by far the most commonly used technique. With simple changes in the X-ray system settings, total radiation dose can be reduced significantly. The purpose of this study was to assess the safety and efficacy of various CIED implantations performed after implementation of a new dose reduction protocol (DRP). METHODS AND RESULTS: We conducted a retrospective chart review of 584 patients undergoing CIED implantation or revision in our hospital. Of these patients, 280 (48%) underwent the implantation prior to and 304 (52%) after the DRP introduction. The DRP included various changes for optimized image processing and exposure system settings to enable dose reduction, as well as a reduced frame rates (4 FPS for fluoroscopy and 7.5 FPS for cinematographic images). Of the 584 patients, 53 (9.1%) had a one-chamber pacemaker, 232 (39.7%) a two-chamber pacemaker, 133 (22.8%) a one-chamber ICD, 35 (6.0%) a two-chamber ICD, 82 (14.0%) a CRT (de novo) implantation, and 49 (8.3%) had an upgrade to a CRT device. DRP was associated with a 64% reduction of the dose-area product (1372 ± 2659 vs. 3792 ± 5025 cGcm2, P < 0.001), while fluoroscopy duration (13 ± 15 vs. 13 ± 15 min) and procedural duration (93 ± 52 vs. 92 ± 52 min.) did not significantly increase. Complication rates did not differ significantly between the two groups. CONCLUSION: The DRP proved to effectively reduce radiation dose for all types of CIED implantations. Fluoroscopy time, total procedure time, and the number of complications did not increase after introducing the DRP.

High Patient Satisfaction with Deep Sedation for Catheter Ablation of Cardiac Arrhythmia.

BACKGROUND: Patients' satisfaction with invasive procedures largely relies on periprocedural perception of pain and discomfort. The necessity for intraprocedural sedation during catheter ablation of cardiac arrhythmias for technical reasons is widely accepted, but data on patients' experience of pain and satisfaction with the procedural sedation are scarce. We have assessed patients' pain and discomfort during and after the procedure using a standardized questionnaire. METHODS: One hundred seventeen patients who underwent catheter ablation answered a standardized questionnaire on periprocedural perception of pain and discomfort after different anesthetic protocols with propofol/midazolam with and without additional piritramide and ketamine/midazolam. RESULTS: Patients report a high level of satisfaction with periprocedural sedation with 83% judging sedation as good or very good. The majority of patients was unconscious of the whole procedure and did not recollect experiencing pain. Procedural pain was reported by 7.7% of the patients and 16% reported adverse effects, e.g., postprocedural nausea and episodes of headache. CONCLUSION: The results of our study show that deep sedation during catheter ablation of cardiac arrhythmias is generally well tolerated and patients are satisfied with the procedure. Yet, a number of patients reports pain or adverse events. Therefore, studies comparing different sedation strategies should be conducted in order to optimize sedation and analgesia.

The effect of an ultra-low frame rate and antiscatter grid-less radiation protocol for cardiac device implantations.

BACKGROUND AND AIMS: Antiscatter grids improve image contrast by absorbing scattered x-ray beams, although by removing the antiscatter grid patient dose can be reduced as more x-ray beams reach the image receptor. Additionally, there is a trend toward ultra-low frame rates for radiation dose reduction during various electrophysiology procedures. As for most cardiac device implantations (CIED) image quality demands are usually modest, the purpose of this study was to assess the safety and efficacy of an ultra-low frame rate and scatter grid-less radiation protocol. METHODS/RESULTS: A total of 140 patients undergoing CIED implantation between 2014 and 2017 were included in the study. Seventy patients (50%) implanted after implementation of the antiscatter grid-less and ultra-low frame rate protocol were matched to controls before the dose-reduction protocol was established. Forty patients (28.6%) had a one-chamber pacemaker or one-chamber implantable cardioverter defibrillator (ICD) implantation/revision, 60 (42.9%) had a two-chamber pacemaker or two-chamber ICD implantation/revision, and 40 (28.6%) patients had a cardiac resynchronization therapy device implantation/revision. Removing the antiscatter-grid and lowering the frame rate led to a 73% reduction of the overall dose area product (1,206 ± 2,015 vs 324 ± 422 µGym, P < 0.001). Procedural duration (95 ± 51 minutes vs 82 ± 44 minutes, P  =  0.053) and rate of complications were not significantly different between the two groups. CONCLUSION: The use of an ultra-low frame rate and antiscatter grid-less radiation protocol significantly reduced radiation dose for implantation of CIED and led to very low average patient doses, while procedural duration and complication rates did not increase.

Performance of the New BioMonitor 2-AF Insertable Cardiac Monitoring System: Can Better be Worse?

BACKGROUND: Implantable loop recorders (ILR) are valuable tools for the investigation of patients with suspected arrhythmias. The BioMonitor 2-AF is a novel insertable ILR with enhanced atrial fibrillation (AF) detection algorithm and remote monitoring capability. OBJECTIVE: The objective of this first-in-human study with the BioMonitor 2-AF was to analyze course of P-wave sensing performance and R-wave amplitude, prevalence of false and correctly sensed and classified episodes, and effectiveness of remote monitoring. METHODS: All 19 patients who underwent ILR insertion were included in the BIOTRONIK Home Monitoring® system (BIOTRONIK GmbH, Berlin, Germany). Daily changes in P-wave and R-wave sensing were analyzed over 6 weeks. A breathing test (in- and expiration) was performed in two different body positions at baseline and during a 6-week in-house follow-up to investigate alterations of P-wave and R-wave sensing. RESULTS: R-wave amplitude and the high P-wave visibility (94.4%) remained unchanged during the follow-up period. In most patients both an increase and decrease of R-wave amplitude, and in some cases a complete R-wave vector change (31.6%), was documented during the "breathing test." Change of body position did not alter R-wave sensing amplitude mostly. "Breathing test" and change of body position had no effect on P-wave sensing performance. In 15.8% of the patients, misclassification of episodes as AF or high ventricular rates due to P-wave oversensing occurred. No ILR-related complication occurred. Automatic transmission via BIOTRONIK Home Monitoring® was successful 100% of the time. CONCLUSION: This study demonstrates that the BioMonitor 2-AF is a safe and effective tool for continuous cardiac monitoring.

Catheter ablation of atrial flutter: A survey focusing on post ablation oral anticoagulation management and ECG monitoring.

BACKGROUND: A considerable amount of patients with typical atrial flutter develop atrial fibrillation after cavotricuspid isthmus (CTI) ablation. No uniform recommendations are available to guide anticoagulation regimes or electrocardiogram (ECG) monitoring strategies after this procedure. METHODS: We conducted a web-based survey in electrophysiology (EP) centers in Germany, Switzerland, and Austria. Responses were received from 47 centers. The survey was designed to investigate variations in management of the following: ablation strategy, oral anticoagulation (OAC) management, and ECG monitoring after successful CTI ablation. RESULTS: More than 55% of the participating centers assume that at least every third patient will develop atrial fibrillation during follow-up. Despite this assumption, most EP experts (81%) would still stop OAC after CTI ablation even in patients with higher CHADS2-VA2SC-score, or even perform CTI in asymptomatic patients with the purpose to stop OAC (52%). Most experts agree that ECG monitoring is necessary during follow-up. A majority still rely on short-term monitoring tools like resting ECGs (7%) or Holter ECGs (43%), while continuous monitoring by implantable loop recorders (10%) are rarely used for postablation OAC management. CONCLUSION: A majority of the centers stop OAC in patients with higher CHADS2-VA2SC-score after CTI ablation. There is evidence that this practice might not be safe and lead to an increased number of ischemic strokes during follow-up. This reflects the need for prospective studies to allow for clear guidelines regarding these issues.

Coronary sinus signal amplitude predicts left atrial scarring.

BACKGROUND: Left atrial scarring is recognised as a critical component in the maintenance of atrial fibrillation and is associated with the failure of interventional treatment. Diminished bipolar voltage (LV) has been proposed as a useful tool for left atrial scar quantification. We hypothesised that, due to its anatomic location, signals on the coronary sinus catheter might be used to predict the amount of left atrial low voltage. METHODS AND RESULTS: A total of 124 patients (42% women, average age 66 ± 9 years) were included. Forty-one with paroxysmal and 83 with persistent atrial fibrillation. Left atrial low-voltage (<0.5 mV, measured during sinus rhythm) area size and distribution varied considerably among the included patients (mean: 34.9%; maximum: 94.6%; minimum: 0.4%). Spearman correlation revealed a strong negative correlation between bipolar voltage of the signals on the coronary sinus catheter and the amount of left atrial scarring (R = -0.778, p < .0001). The optimal CS voltage cut off for prediction of left atrial low-voltage size of ≥50% was 1.9 mV with an area-under-the receiver-operating-characteristic (ROC) curve of 0.982, a sensitivity of 97% and a specificity of 98%. CONCLUSIONS: There is a strong negative correlation between the size of left atrial low-voltage areas (LVA) and coronary sinus signal amplitude. With increasing left atrial LVA size, CS signal amplitudes decrease, and vice versa. On the basis of these findings, average CS signal amplitudes of ≤1.9 mV can be used as a predictor for a left atrial low-voltage size of ≥50%.

Pain Reactions during Pulmonary Vein Isolation under Deep Sedation: Cryothermal versus Radiofrequency Ablation.

BACKGROUND: Left atrial ablation can be accompanied by discomfort or pain. The purpose of this study was to systematically compare pain reactions during ablation of atrial fibrillation under deep sedation with cryothermal and radiofrequency energy. METHODS AND RESULTS: Circumferential ablation was performed in patients with atrial fibrillation using either radiofrequency (RF) or cryoenergy. Deep sedation was achieved with a combination of propofol and midazolam. Pain reactions were counted and painful ablation sites located. To determine the severity of the pain reactions a Face, Legs, Activity, Cry, Consolability (FLACC) Behavioral Pain Assessment Scale was used: 79 patients (53 RF- vs 26 Cryoablations) were included. A total of 92% of patients treated with RF energy showed ≥1 pain reaction during the procedure compared to only 13% in the cryoenergy group (<0.001). The total number of pain reactions was significantly higher in the RF energy group (3.6 ± 4.7 vs1.3 ± 0.6, P = 0.005). Determination of painful sites was performed in the RF group only. Pain reactions were significantly more often observed during RF application left superior pulmonary vein (LSPV) ostium compared to other left atrial ablation sites (Total FLACC Score 2.8 ± 0.6 LSPV, 1.4 ± 0.4 left inferior pulmonary vein [P = 0.009], 1.4 ± 0.3 right superior pulmonary vein [P = 0.044], 1.1 ± 0.3 right inferior pulmonary vein [P = 0.032]). CONCLUSIONS: Our results show that despite deep sedation pain reactions often occur during RF ablation. Knowledge of areas with more frequent pain reactions may help electrophysiologists to reduce pain reactions and related patient movements. Ablation with cryoenergy was significantly less painful compared to ablation with RF energy. Cryoablation therefore may be considered for patients at a higher risk for anesthesia-related complications.

Atrial rhythm influences catheter tissue contact during radiofrequency catheter ablation of atrial fibrillation: comparison of contact force between sinus rhythm and atrial fibrillation.

Catheter tissue contact force (CF) is an important factor for durable lesion formation during radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF). Since CF varies in the beating heart, atrial rhythm during RFCA may influence CF. A high-density map and RFCA points were obtained in 25 patients undergoing RFCA of AF using a CF-sensing catheter (Tacticath, St. Jude Medical). The operators were blinded to the CF information. Contact type was classified into three categories: constant, variable, and intermittent contact. Average CF and contact type were analyzed according to atrial rhythm (SR vs. AF) and anatomical location. A total of 1364 points (891 points during SR and 473 points during AF) were analyzed. Average CFs showed no significant difference between SR (17.2 ± 11.3 g) and AF (17.2 ± 13.3 g; p = 0.99). The distribution of points with an average CF of ≥20 and <10 g also showed no significant difference. However, the distribution of excessive CF (CF ≥40 g) was significantly higher during AF (7.4 %) in comparison with SR (4.2 %; p < 0.05). At the anterior area of the right inferior pulmonary vein (RIPV), the average CF during AF was significantly higher than during SR (p < 0.05). Constant contact was significantly higher during AF (32.2 %) when compared to SR (9.9 %; p < 0.01). Although the average CF was not different between atrial rhythms, constant contact was more often achievable during AF than it was during SR. However, excessive CF also seems to occur more frequently during AF especially at the anterior part of RIPV.

Cardiovascular Magnetic Resonance Imaging in Patients with an Implantable Loop Recorder.

BACKGROUND: Implantable loop recorders (ILRs) allow continuous cardiac monitoring for 3-6 years and are a valuable tool for the investigation of syncopal episodes, palpitations, and atrial fibrillations as well as risk stratification after myocardial infarction. Although magnetic resonance imaging (MRI) in patients with ILRs has been shown to be safe, the impact of ILRs on cardiac MRI image quality has not been investigated yet. Thus, we tested the diagnostic value of cardiac MRI in patients with various types of ILRs. METHODS: Two patients with an ILR and a clinical indication to assess myocardial burden of scarring and fibrosis or stress-induced myocardial ischemia underwent cardiac MRI. Device interrogation was performed prior to, immediately after, and 3 months after cardiac MRI. RESULTS: The post-MRI follow-ups revealed no change in programmed ILR parameters, sensing fidelity, and battery parameters. However, ILRs caused significant, uninterpretable hyperintensity artifacts in cardiac MRI. CONCLUSIONS: Further clinical studies are warranted to investigate whether modified MRI techniques are helpful to eliminate imaging artifacts.