High-Fidelity 3D Stray Magnetic Field Mapping of Smartphones to Address Safety Considerations with Active Implantable Electronic Medical Devices.

Case reports indicate that magnets in smartphones could be a source of electromagnetic interference (EMI) for active implantable medical devices (AIMD), which could lead to device malfunction, compromising patient safety. Recognizing this challenge, we implemented a high-fidelity 3D magnetic field mapping (spatial resolution 1 mm) setup using a three-axis Hall probe and teslameter, controlled by a robot (COSI Measure). With this setup, we examined the stray magnetic field of an iPhone 13 Pro, iPhone 12, and MagSafe charger to identify sources of magnetic fields for the accurate risk assessment of potential interferences with AIMDs. Our measurements revealed that the stray fields of the annular array of magnets, the wide-angle camera, and the speaker of the smartphones exceeded the 1 mT limit defined by ISO 14117:2019. Our data-driven safety recommendation is that an iPhone 13 Pro should be kept at least 25 mm away from an AIMD to protect it from unwanted EMI interactions. Our study addresses safety concerns due to potential device-device interactions between smartphones and AIMDs and will help to define data-driven safety guidelines. We encourage vendors of electronic consumer products (ECP) to provide information on the magnetic fields of their products and advocate for the inclusion of smartphones in the risk assessment of EMI with AIMDs.

First clinical experience of high-power ablation of atrial fibrillation with a novel contact force-sensing gold-tip catheter.

BACKGROUND: Contact force (CF)-sensing catheters are commonly used in the field of radiofrequency (RF) ablation to treat atrial fibrillation (AF). Increasing ablation power (e.g., 50 W) has been suggested as a method to reduce procedure times whilst creating safe and lasting lesions. METHODS: We report the first clinical evidence of a 50 W point-by-point RF ablation in 25 consecutive patients with symptomatic AF using a novel CF-sensing catheter with a gold tip (AlCath Force, Biotronik). We collected and analyzed procedural and ablation parameters. The safety and efficacy of the catheter were evaluated. RESULTS: Altogether, 985 RF lesions in 25 patients were created with a mean number of 39.4 ± 16.3 lesions per patient. The total skin-to-skin procedure time was 116.1 ± 35.1 min, and the mean total area dose product was 10.9 ± 5.1 Gy*cm2. The mean RF time per procedure was 13.2 ± 6.6 min. The mean RF time per lesion was 20.2 ± 8.4 s. The mean CF was 15.7 ± 7.6 g. We observed a mean force time integral of 274.7 ± 11.1 gs (range: 53 to 496 gs). Acute procedural success, defined as entrance and exit block in all pulmonary veins, could be obtained in all cases. No procedure- or device-related serious adverse events were observed. No audible steam pops occurred. Optical inspection of the catheter after the procedure showed neither charring nor clotting. CONCLUSIONS: We provide the first evidence for the safety and efficacy of 50 W ablation using the AlCath Force gold-tip catheter. These data must be supported by a larger multi-center study.

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.

Magnetic field-induced interactions between phones containing magnets and cardiovascular implantable electronic devices: Flip it to be safe?

BACKGROUND: Recent case reports and small studies have reported activation of the magnet-sensitive switches in cardiovascular implantable electronic devices (CIEDs) by the new iPhone 12 series, initiating asynchronous pacing in pacemakers and suspension of antitachycardia therapies in implantable cardioverter-defibrillators (ICDs). OBJECTIVE: The purpose of this prospective single-center observational study was to quantify the risk of magnetic field interactions of the iPhone 12 with CIEDs. METHODS: A representative model of each CIED series from all manufacturers was tested ex vivo. Incidence and minimum distance necessary for magnet mode triggering were analyzed in 164 CIED patients with either the front or the back of the phone facing the device. The magnetic field of the iPhone 12 was analyzed using a 3-axis Hall probe. RESULTS: Ex vivo, magnetic interference occurred in 84.6% with the back compared to 46.2% with the front of the iPhone 12 facing the CIED. In vivo, activation of the magnet-sensitive switch occurred in 30 CIED patients (18.3%; 21 pacemaker, 9 ICD) when the iPhone 12 was placed in close proximity over the CIED pocket and the back of the phone was facing the skin. Multiple binary logistic regression analysis identified implantation depth (95% confidence interval 0.02-0.24) as an independent predictor of magnet-sensitive switch activation. CONCLUSION: Magnetic field interactions occur only in close proximity and with precise alignment of the iPhone 12 and CIEDs. It is important to advise CIED patients to not put the iPhone 12 directly on the skin above the CIED. Further recommendations are not necessary.

COVID19-associated cardiomyocyte dysfunction, arrhythmias and the effect of Canakinumab.

BACKGROUND: Cardiac injury associated with cytokine release frequently occurs in SARS-CoV-2 mediated coronavirus disease (COVID19) and mortality is particularly high in these patients. The mechanistic role of the COVID19 associated cytokine-storm for the concomitant cardiac dysfunction and associated arrhythmias is unclear. Moreover, the role of anti-inflammatory therapy to mitigate cardiac dysfunction remains elusive. AIMS AND METHODS: We investigated the effects of COVID19-associated inflammatory response on cardiac cellular function as well as its cardiac arrhythmogenic potential in rat and induced pluripotent stem cell derived cardiomyocytes (iPS-CM). In addition, we evaluated the therapeutic potential of the IL-1ß antagonist Canakinumab using state of the art in-vitro confocal and ratiometric high-throughput microscopy. RESULTS: Isolated rat ventricular cardiomyocytes were exposed to control or COVID19 serum from intensive care unit (ICU) patients with severe ARDS and impaired cardiac function (LVEF 41±5%; 1/3 of patients on veno-venous extracorporeal membrane oxygenation; CK 154±43 U/l). Rat cardiomyocytes showed an early increase of myofilament sensitivity, a decrease of Ca2+ transient amplitudes and altered baseline [Ca2+] upon exposure to patient serum. In addition, we used iPS-CM to explore the long-term effect of patient serum on cardiac electrical and mechanical function. In iPS-CM, spontaneous Ca2+ release events were more likely to occur upon incubation with COVID19 serum and nuclear as well as cytosolic Ca2+ release were altered. Co-incubation with Canakinumab had no effect on pro-arrhythmogenic Ca2+ release or Ca2+ signaling during excitation-contraction coupling, nor significantly influenced cellular automaticity. CONCLUSION: Serum derived from COVID19 patients exerts acute cardio-depressant and chronic pro-arrhythmogenic effects in rat and iPS-derived cardiomyocytes. Canakinumab had no beneficial effect on cellular Ca2+ signaling during excitation-contraction coupling. The presented method utilizing iPS-CM and in-vitro Ca2+ imaging might serve as a novel tool for precision medicine. It allows to investigate cytokine related cardiac dysfunction and pharmacological approaches useful therein.

Case Report: Assessing the Position of Pacemaker Leads via Transthoracic Echocardiography: Additional Value of the Subcostal En Face View.

There is an association between presence of cardiac implantable electronic devices (CIED) and development of tricuspid regurgitation (TR). Mechanisms proposed to explain CIED-induced TR can be classified as implantation-related, lead-related, and pacing-related. Lead-related TR results from the direct interaction of the lead with the tricuspid valve (TV). The localization of the lead at the TV level directly influences the probability of subsequent development of significant TR. A transthoracic subcostal en face view of the TV can be acquired in most patients through a 90° rotation from the subcostal 4-chamber view with clear anatomic delineation of the TV and the commissures including lead position. This case-series presents three examples where the transthoracic en face view could add incremental information on the position of the pacemaker leads and on the mechanism of TR. Conclusion: When performing transthoracic echocardiography in patients with trans-tricuspid CIED lead(s), an en face view of the TV with exact reporting of the position of the lead(s) should be included.

Wearable cardioverter-defibrillator: friend or foe in suspected myocarditis?

AIM: Wearable cardioverter defibrillator (WCD, LifeVest, and Zoll) therapy has become a useful tool to bridge a temporarily increased risk for sudden cardiac death. However, despite extensive use, there is a lack of evidence whether patients with myocarditis and impaired LVEF may benefit from treatment with a WCD. METHODS AND RESULTS: We conducted a single-centre retrospective observational study analysing patients with a WCD prescribed between September 2015 and April 2020 at our institution. In total, 135 patients were provided with a WCD, amongst these 76 patients (mean age 48.9 ± 13.7 years; 84.2% male) for clinically suspected myocarditis. Based on the results of the endomyocardial biopsy and, where available cardiac magnetic resonance imaging, 39 patients (51.3%) were diagnosed with myocarditis and impaired LVEF and 37 patients (48.7%) with dilated cardiomyopathy (DCM) without evidence of cardiac inflammation. The main immunohistopathological myocarditis subtype was lymphocytic myocarditis in 36 (92.3%) patients, and four patients (10.3%) of this group had an acute myocarditis. Three patients had cardiac sarcoidosis (7.7%). Ventricular tachycardia occurred in seven myocarditis (in total 41 VTs; 85.4% non-sustained) and one DCM patients (in total one non-sustained ventricular tachycardia). Calculated necessary WCD wearing time until ventricular tachycardia occurrence is 86.41 days in myocarditis compared with 6.46 years in DCM patients. CONCLUSIONS: Our data suggest that myocarditis patients may benefit from WCD therapy. However, as our study is not powered for outcome, further randomized studies powered for the outcome morbidity and mortality are necessary.

Performance of a cardiac lipid panel compared to four prognostic scores in chronic heart failure.

The cardiac lipid panel (CLP) is a novel panel of metabolomic biomarkers that has previously shown to improve the diagnostic and prognostic value for CHF patients. Several prognostic scores have been developed for cardiovascular disease risk, but their use is limited to specific populations and precision is still inadequate. We compared a risk score using the CLP plus NT-proBNP to four commonly used risk scores: The Seattle Heart Failure Model (SHFM), Framingham risk score (FRS), Barcelona bio-HF (BCN Bio-HF) and Meta-Analysis Global Group in Chronic Heart Failure (MAGGIC) score. We included 280 elderly CHF patients from the Cardiac Insufficiency Bisoprolol Study in Elderly trial. Cox Regression and hierarchical cluster analysis was performed. Integrated area under the curves (IAUC) was used as criterium for comparison. The mean (SD) follow-up period was 81 (33) months, and 95 (34%) subjects met the primary endpoint. The IAUC for FRS was 0.53, SHFM 0.61, BCN Bio-HF 0.72, MAGGIC 0.68, and CLP 0.78. Subjects were partitioned into three risk clusters: low, moderate, high with the CLP score showing the best ability to group patients into their respective risk cluster. A risk score composed of a novel panel of metabolite biomarkers plus NT-proBNP outperformed other common prognostic scores in predicting 10-year cardiovascular death in elderly ambulatory CHF patients. This approach could improve the clinical risk assessment of CHF patients.

Low-voltage shock impedance measurements: A false sense of security.

BACKGROUND: Implantable cardioverter defibrillators use low-voltage shock impedance measurements to monitor the lead integrity. However, previous case reports suggest that low-voltage shock impedance measurements may fail to detect insulation breaches that can cause life-threatening electrical short circuits. METHODS AND RESULTS: We report six cases of insulation breaches in transvenous defibrillation leads that were not obvious during standard interrogations and testing of the lead beforehand. In two cases, an electrical short circuit during commanded shock delivery for internal electrical cardioversion resulted in a total damage of the ICD generator. In one of these cases, commanded shock delivery induced ventricular fibrillation, which required external defibrillation. In two cases, a shock due to ventricular tachycardia was aborted as the shock impedance was less than 20 Ω. However, in both cases the tiny residual shock energy terminated the ventricular tachycardia. In contrast, in one case the residual energy of the aborted shock did not end ventricular fibrillation induced at defibrillator threshold testing. In one case, the ICD indicated an error code for a short circuit condition detected during an adequate shock delivery. CONCLUSIONS: This case series illustrates that low-voltage shock impedance measurements can fail to detect insulation breaches. These data suggest that in patients without a contraindication, traditional defibrillator threshold testing or high voltage synchronized shock at the time of device replacement should be considered.

Quantitative evaluation of different high-density 3D mapping modes for atrial and ventricular substrate assessment of cardiac arrhythmias with the HD grid catheter.

BACKGROUND: Atrial and ventricular arrhythmias significantly contribute to morbidity and mortality of patients with cardiac disease. Ablation of these arrhythmias has shown to improve clinical outcomes, yet targeted ablation strategies rely on proper mapping capabilities. In the present study, we compare different modes of high-resolution mapping in clinically relevant arrhythmias using HD grid. METHODS AND RESULTS: Using the Advisor™ HD Grid Mapping Catheter in either the standard, the wave (bipolar along spline and bipolar orthogonal) or the wave diagonal setting, low-voltage areas were determined. Low-voltage was defined as local electrograms with an amplitude <0.5 mV (bipolar; atria/ventricle) or <4 mV (unipolar; ventricle). Ultra high-density mapping in 47 patients with ventricular tachycardia, ventricular premature beats, atrial fibrillation and atrial tachycardia provided reliable information for the understanding of the arrhythmia mechanism resulting in safe ablation procedures. Regions of low voltage were significantly decreased by 14 ± 2% and 31 ± 3% with wave and wave diagonal settings as compared to standard settings, respectively. CONCLUSION: Substrate mapping and risk stratification relies on proper low voltage discrimination. Even though the Advisor™ HD Grid Mapping Catheter was safely used in all cases, the extent of low voltage areas was mapping-mode dependent.

Are Contemporary Smartwatches and Mobile Phones Safe for Patients With Cardiovascular Implantable Electronic Devices?

OBJECTIVES: Given the increasing prevalence of mobile phone and smartwatch use, this study tested patients with cardiovascular implantable electronic devices (CIEDs) for the incidence and consequence of contemporary mobile phone and smartwatch-produced electromagnetic interferences. BACKGROUND: Electromagnetic interferences can be hazardous for patients with CIEDs. METHODS: In total, 148 patients with CIEDs and leads from 4 different manufacturers were subjected to 1,352 tests. Analyzed CIEDs included 51 pacemakers, 5 cardiac resynchronization therapy pacemakers, 46 implantable cardioverter-defibrillators, 43 cardiac resynchronization therapy defibrillators, and 3 implantable loop recorders. To analyze a possible influence of certain distances between the mobile phone (iPhone 6) and the smartwatch (Apple Watch A1553) to the CIED, both were placed either directly above implanted devices or at the right wrist. All possible activations of the iPhone and the Apple Watch, including the standby, dialing, and connecting modes (telephone connection and Internet access) were tested. In addition, we studied incidence and characteristics of interferences with interrogation telemetry. RESULTS: In this study, only a single case of mobile phone-induced electromagnetic interference on a dual-chamber pacemaker was observed. Utilizing wanded telemetry, iPhone induced interferences were found in 14% of the patients. However, none of the patients showed any interference with the Apple Watch. CONCLUSIONS: The risk of electromagnetic interferences of the iPhone 6 and the Apple Watch with CIEDs is low. However, close proximity of the iPhone 6 to implanted devices can cause telemetry interferences.

The effect of iron deficiency on cardiac resynchronization therapy: results from the RIDE-CRT Study.

AIMS: Cardiac resynchronization therapy (CRT) improves functional status, induces reverse left ventricular remodelling, and reduces hospitalization and mortality in patients with symptomatic heart failure, left ventricular systolic dysfunction, and QRS prolongation. However, the impact of iron deficiency on CRT response remains largely unclear. The purpose of the study was to assess the effect of functional and absolute iron deficiency on reverse cardiac remodelling, clinical response, and outcome after CRT implantation. METHODS AND RESULTS: The relation of iron deficiency and cardiac resynchronization therapy response (RIDE-CRT) study is a prospective observational study. We enrolled 77 consecutive CRT recipients (mean age 71.3 ± 10.2 years) with short-term follow-up of 3.3 ± 1.9 months and long-term follow-up of 13.0 ± 3.2 months. Primary endpoints were reverse cardiac remodelling on echocardiography and clinical CRT response, assessed by change in New York Heart Association classification. Echocardiographic CRT response was defined as relative improvement of left ventricular ejection fraction ≥ 20% or left ventricular global longitudinal strain ≥ 20%. Secondary endpoints were hospitalization for heart failure and all-cause mortality (mean follow-up of 29.0 ± 8.4 months). At multivariate analysis, iron deficiency was identified as independent predictor of echocardiographic (hazard ratio 4.97; 95% confidence interval 1.15-21.51; P = 0.03) and clinical non-response to CRT (hazard ratio 4.79; 95% confidence interval 1.30-17.72, P = 0.02). We found a significant linear-by-linear association between CRT response and type of iron deficiency (P = 0.004 for left ventricular ejection fraction improvement, P = 0.02 for left ventricular global longitudinal strain improvement, and P = 0.003 for New York Heart Association response). Iron deficiency was also significantly associated with an increase in all-cause mortality (P = 0.045) but not with heart failure hospitalization. CONCLUSIONS: Iron deficiency is a negative predictor of effective CRT therapy as assessed by reverse cardiac remodelling and clinical response. Assessment of iron substitution might be a relevant treatment target to increase CRT response and outcome in chronic heart failure patients.

The force stability of tissue contact and lesion size index during radiofrequency ablation: An ex-vivo study.

INTRODUCTION: Radiofrequency (RF) ablation is a commonly used tool in the invasive electrophysiology laboratory to treat a variety of rhythm disorders. Reliable creation of transmural ablation lesions is crucial for long-term success. Lesion size index (LSI) is a multiparametric index that incorporates time, power, contact force (CF), and impedance data recorded during RF ablation in a weighted formula and has been shown to predict the extent of myocardial tissue lesions. Whether the force stability of contact influences lesion size in LSI-guided ablations is unknown. OBJECTIVES: The aim of this study was to analyze the influence of the force stability of contact on lesion size during LSI-guided ablations in an ex-vivo model. METHODS AND RESULTS: A total of 267 RF lesions (n = 6 hearts) were created on porcine myocardial slabs by using an open-tip irrigated ablation catheter with the following settings: 35 W with either intermittent (varied between 0 and up to 20 g), variable (10 to 20 g), or constant tissue contact (15 g) in a perpendicular or parallel fashion (applied manually) up to a target LSI of either 5 or 6. Subsequently, lesion width and depth were determined. Lesion width was mainly influenced by catheter tip orientation and LSI, whereas lesion depth was mainly influenced by LSI alone. The force stability of catheter contact had no relevant impact on lesion width or depth. CONCLUSION: The force stability of catheter contact has only little effect on lesion depth or width in LSI-guided catheter ablation while the catheter orientation primarily affects lesion width.

Implantable loop recorders in patients with unexplained syncope: Clinical predictors of pacemaker implantation.

BACKGROUND: Implantable loop recorders (ILR) are a valuable tool for the investigation of unexplainedsyncopal episodes. The aim of this retrospective single center study was to identify predictive factors for pacemaker implantation in patients with unexplained syncope who underwent ILR insertion. METHODS: One hundred six patients were retrospectively analyzed (mean age 59.1 years; 47.2% male) with unexplained syncope and negative conventional testing who underwent ILR implantation. The pri- mary study endpoint was detection of symptomatic or asymptomatic bradycardia requiring pacemaker implantation. RESULTS: The average follow-up period after ILR implantation was 20 ± 15 months. Pacemaker im- plantation according to current guidelines was necessary in 22 (20.8%) patients, mean duration until index bradycardia was 81 ± 88 (2-350) days. Ten (45.5%) patients received a pacemaker due to sinus arrest, 7 (31.8%) patients due to third-degree atrioventricular block, 2 (9.1%) patients due to second- degree atrioventricular block and 1 (4.5%) patient due to atrial fibrillation with a slow ventricular rate. Three factors remained significant in multivariate analysis: obesity, which defined by a body mass index above 30 kg/m2 (OR: 7.39, p = 0.014), a right bundle branch block (OR: 9.40, p = 0.023) and chronic renal failure as defined by a glomerular filtration rate of less than 60 mL/min (OR: 6.42, p = 0.035). CONCLUSIONS: Bradycardia is a frequent finding in patients undergoing ILR implantation due to un- explained syncope. Obesity, right bundle branch block and chronic renal failure are independent clinical predictors of pacemaker implantation.

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.

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.

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.

Cardiac device implantations in obese patients: Success rates and complications.

BACKGROUND: Obesity is associated with increased complications and potentially worse outcomes for various cardiac interventions. This study analyzed the success rate and complication rates associated with implantation of cardiac implantable electronic devices (CIEDs) in obese patients. HYPOTHESIS: Success rates are lower and complication rates higher in obese patients. METHODS: Consecutive patients undergoing CIED implantation between 2011 and 2015 in our hospital were included. Patients were categorized into obese and nonobese groups according to body mass index (BMI); cutoff was 30 kg/m2 . Patient characteristics, complication rates, procedural duration, and fluoroscopy data were compared between the 2 groups. RESULTS: A total of 965 patients (mean age, 69.0 ± 12.9 years; 67% male) were included. Of these, 249 (25.8%) patients were classified obese and 716 (74.2%) nonobese. Mean BMI was 34.7 ± 4.7 kg/m2 vs 25.1 ± 3.0 kg/m2 , respectively. There was no difference in procedural success rates between the 2 groups (97.2% vs 97.1%, respectively). Major complications were significantly lower in the obese group compared with the nonobese group (11 [4.4%] vs 62 [8.7%]; P < 0.05). Procedural duration and fluoroscopy duration were not different between the 2 groups, but the total dose-area product was significantly higher in obese patients vs nonobese patients (4012 ± 5416 cGcm2 vs 2692 ± 5277 cGcm2 ; P < 0.005). CONCLUSIONS: CIED implantation can be safely and effectively achieved in patients with BMI >30 kg/m2 . However, total radiation dose was significantly higher in the obese group, emphasizing that efforts should be made to reduce radiation exposure in these patients.

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.

Clinical Relevance of Left Atrial Strain to Predict Recurrence of Atrial Fibrillation after Catheter Ablation: A Meta-Analysis.

BACKGROUND: The purpose of this meta-analysis was to analyze the clinical relevance of left atrial (LA) strain to predict recurrence of atrial fibrillation (AF) after catheter ablation (CA). METHODS AND RESULTS: We searched in different databases (Medline, EMBASE, and Cochrane) prospective studies that analyzed LA strain before CA. Eight studies (2 with only paroxysmal AF and 6 with mixed population of paroxysmal and persistent AF) were included in the final analysis (total patient number = 686). Patients with recurrence of AF were principally characterized by lower LA strain in comparison with those without AF recurrence (mean 18.4% [range 8.8-24.5%] versus 25.3% [13.6-32.7%], weighted mean difference -4.89% [95% CI -5.83% to -3.95%], P < 0.001). In addition, receiver operating curves shown that LA strain was strongly associated with recurrence of AF after CA (weighted mean: AUC 0.798 [95% CI 0.700-0.943], cutoff 22.8% [18.8-30%], sensitivity 78% [65-86%], and specificity 75% [66-100%]). In line, these results were similar using LA strain with QRS-analysis and P-analysis as well as using different software package such as Echo-Pac, QLab, TomTec, and VVI. CONCLUSION: In patients with AF candidate for CA, the analysis of the LA using LA strain could be of great usefulness to identify patients with high risk of AF recurrence. Nonetheless, further studies are needed to establish the clinical relevance of LA strain in patients with persistent AF.