Relation between hematocrit partitioning and red blood cell lingering in a microfluidic network.

Despite increased interest in the effect of lingering red blood cells (LRBCs) on the heterogeneous hematocrit distribution in the microcirculation, quantitative data on LRBCs before and after the lingering event are still limited. The aim of the study was to investigate the relation between red blood cell (RBC) lingering and hematocrit partitioning in a microfluidic model of a microvascular bifurcation in the limit of low hematocrit conditions (tube hematocrit <10%). To this end, the classification of LRBCs was performed based on timing, position, and velocity of the RBCs. The investigation provided statistical information on the velocity, shape, and orientation of LRBCs as well as on their lateral distribution in the parent and daughter vessels. LRBCs traveled predominantly close to the centerline of the parent vessel, but they marginated close to the distal wall in the daughter vessels. Differently than the RBC flow observed in the smallest vessels, no influence of lingering events on the local hematocrit partitioning was observed in our experiments. However, importantly, we found that LRBCs flowing in the daughter vessel after lingering may be connected to reverse hematocrit partitioning in downstream bifurcations by influencing the skewness of the hematocrit distribution in the daughter vessel, which relates to the so-called network history effect.

Impact of comorbidity on complication rates and life expectancy in patients with a leadless pacemaker.

BACKGROUND: Knowledge about impact of age and comorbidities on outcome in patients with leadless pacemakers (LPM) is limited. OBJECTIVES: To analyse outcome in LPM patients according to age and comorbidities. METHODS: This Swiss, multi-centre, retrospective analysis includes all patients with LPM implanted between 2015 and 2022. Charlson-Comorbidity-Index (CCI) was determined and patients were divided into a low- (CCI ≤ 5) and high-comorbidity (CCI > 5) group. Peri-procedural complications, in-hospital death, and all-cause mortalities were assessed. Finally, all-cause mortality according to three groups (CCI ≤ 3, 4-5, >5) was compared to age and sex-adjusted mortality in the general Swiss population. RESULTS: 863 patients (median age 81 years, 65% male, 42% with CCI > 5) were included. Peri-procedural/long-term complication rates did not differ between the low- vs. high-comorbidity groups (2.6% vs. 1.7%, p = 0.48 and 1.2% vs. 2.8%, p = 0.12, respectively). In-hospital (3.6% vs. 0.6%, p = 0.002) and all-cause mortality (HR 2.9, 95%CI 2.2-3.8, p < 0.001) were significantly higher in the high-comorbidity group resulting in a three-year mortality of 58% (95%CI 51-65%) vs. 22% (95%CI 17-27%) in the low-comorbidity group. In patients with a CCI ≤ 3, all-cause mortality was comparable to the age- and sex-adjusted mortality of the general Swiss population. CONCLUSIONS: In elderly patients with high comorbidity, LPM implantation was not associated with increased peri-procedural/long-term complications. All-cause mortality in LPM patients with a CCI ≤ 3 was comparable to age- and sex-adjusted mortality in the general Swiss population. Despite a relatively high three-year mortality due to competing risk factors, LPM implantation is safe, even in elderly patients with high comorbidity. CONDENSED ABSTRACT: In this Swiss, multi-centre, retrospective cohort analysis, 863 patients implanted with a leadless pacemaker were included and divided into a high-comorbidity (with a CCI > 5) and low-comorbidity (with a CCI ≤ 5) group. There was no between group difference in terms of implantation outcomes and peri-operative or long-term complications. Furthermore, all-cause mortality during follow-up in patients with a CCI ≤ 3 was comparable to age- and sex-adjusted mortality in the general Swiss population. These data indicate that LPM implantation is a safe procedure, even in elderly patients with high comorbidity.

KCNQ1 suppression-replacement gene therapy in transgenic rabbits with type 1 long QT syndrome.

BACKGROUND AND AIMS: Type 1 long QT syndrome (LQT1) is caused by pathogenic variants in the KCNQ1-encoded Kv7.1 potassium channels, which pathologically prolong ventricular action potential duration (APD). Herein, the pathologic phenotype in transgenic LQT1 rabbits is rescued using a novel KCNQ1 suppression-replacement (SupRep) gene therapy. METHODS: KCNQ1-SupRep gene therapy was developed by combining into a single construct a KCNQ1 shRNA (suppression) and an shRNA-immune KCNQ1 cDNA (replacement), packaged into adeno-associated virus serotype 9, and delivered in vivo via an intra-aortic root injection (1E10 vg/kg). To ascertain the efficacy of SupRep, 12-lead electrocardiograms were assessed in adult LQT1 and wild-type (WT) rabbits and patch-clamp experiments were performed on isolated ventricular cardiomyocytes. RESULTS: KCNQ1-SupRep treatment of LQT1 rabbits resulted in significant shortening of the pathologically prolonged QT index (QTi) towards WT levels. Ventricular cardiomyocytes isolated from treated LQT1 rabbits demonstrated pronounced shortening of APD compared to LQT1 controls, leading to levels similar to WT (LQT1-UT vs. LQT1-SupRep, P < .0001, LQT1-SupRep vs. WT, P = ns). Under ß-adrenergic stimulation with isoproterenol, SupRep-treated rabbits demonstrated a WT-like physiological QTi and APD90 behaviour. CONCLUSIONS: This study provides the first animal-model, proof-of-concept gene therapy for correction of LQT1. In LQT1 rabbits, treatment with KCNQ1-SupRep gene therapy normalized the clinical QTi and cellular APD90 to near WT levels both at baseline and after isoproterenol. If similar QT/APD correction can be achieved with intravenous administration of KCNQ1-SupRep gene therapy in LQT1 rabbits, these encouraging data should compel continued development of this gene therapy for patients with LQT1.

Electrophysiological differences of randomized deep sedation with dexmedetomidine versus propofol.

BACKGROUND: Dexmedetomidine and propofol are common sedatives in intensive care units and for interventional procedures. Both may compromise sinus node function and atrioventricular conduction. The objective of this prospective, randomized study is to compare the effect of dexmedetomidine with propofol on sinus node function and atrioventricular conduction. METHODS: In a tertiary care center in Switzerland we included from September 2019 to October 2020 160 patients (65 ± 11 years old; 32% female) undergoing first ablation for atrial fibrillation by cryoballoon ablation or by radiofrequency ablation. Patients were randomly assigned to deep sedation with dexmedetomidine (DEX group) versus propofol (PRO group). A standard electrophysiological study was performed after pulmonary vein isolation with the patients still deeply sedated and hemodynamically stable. RESULTS: Eighty patients each were randomized to the DEX and PRO group. DEX group patients had higher baseline sinus cycle length (1022 vs. 1138 ms; p = 0.003) and longer sinus node recovery time (SNRT400; 1597 vs. 1412 ms; p = 0.042). However, both corrected SNRT and normalized SNRT did not differ. DEX group patients had longer PR interval (207 vs. 186 ms; p = 0.002) and AH interval (111 vs. 95 ms, p = 0.008), longer Wenckebach cycle length of the atrioventricular node (512 vs. 456 ms; p = 0.005), and longer atrioventricular node effective refractory period (390 vs. 344 ms; p = 0.009). QRS width and HV interval were not different. An arrhythmia, mainly atrial fibrillation, was induced in 33 patients during the electrophysiological study, without differences among groups (20% vs. 15%, p = 0.533). CONCLUSIONS: Dexmedetomidine has a more pronounced slowing effect on sinus rate and suprahissian AV conduction than propofol, but not on infrahissian AV conduction and ventricular repolarization. These differences need to be taken into account when using these sedatives. TRIAL REGISTRATION: ClinicalTrials.gov number NCT03844841, 19/02/2019.

A leadless ventricular pacemaker providing atrioventricular synchronous pacing in the real-world setting: 12-Month results from the Micra AV post-approval registry.

BACKGROUND: Advances in leadless pacemaker technology have enabled accelerometer-based atrioventricular (AV) synchronous pacing by sensing atrial mechanical contraction. OBJECTIVE: The purpose of this study was to report the performance of the Micra AV leadless pacemaker from the worldwide Micra AV post-approval registry (PAR) through 12 months. METHODS: The Micra AV PAR is a prospective, single-arm, observational registry designed to assess the safety and effectiveness of Micra AV in a real-world setting. For the present interim analysis, major complications and system revisions through 12 months were summarized and compared to a historical cohort of 2667 patients implanted with a transvenous dual-chamber pacing system. RESULTS: The device was successfully implanted in 796 of 801 patients (99.4%) at 97 centers in 19 countries. Micra AV patients were older (74.1 years vs 71.1 years; P < .0001) with a higher incidence of renal disease (22.3% vs 9.8%; P < .0001) compared with transvenous dual-chamber patients. Through 12 months, the major complication rate was 3.7% in Micra AV patients compared with 8.8% in transvenous dual-chamber patients (hazard ratio 0.42; 95% confidence interval 0.28-0.61; P < .001). The system revision rate was 1.5% in Micra AV patients compared with 5.5% for transvenous dual-chamber patients (hazard ratio 0.25; 95% confidence interval 0.13-0.47; P < .001); this reduction was largely driven by the absence of lead dislodgments requiring revision. The median AV synchrony index was 79.4% (interquartile range 65.2%-86.4%) in patients paced >90%. CONCLUSION: The Micra AV leadless pacemaker was implanted with a high rate of success in patients with multiple comorbidities, with a significantly lower rate of complications and system revisions through 12 months compared to a historical cohort of patients with transvenous dual-chamber pacemakers.

Pulsed-field ablation for repeat procedures after failed prior thermal ablation for atrial fibrillation.

Background: Pulsed-field ablation (PFA) is a novel nonthermal ablation technology. Its potential value for repeat procedures after unsuccessful thermal ablation for atrial fibrillation has not been assessed. Objective: The purpose of this study was to summarize our initial experience with patients undergoing repeat procedures using PFA. Methods: Consecutive patients with arrhythmia recurrences after a prior thermal ablation undergoing a repeat procedure using a multipolar PFA catheter from May 2021 and December 2022 were included. After 3-dimensional electroanatomic mapping, reconnected pulmonary veins (PVs) were reisolated and veins with only ostial isolation wither ablated to widen antral PV isolation. Posterior wall ablation was performed if all PVs were durably isolated or in case of low-voltage areas on the posterior wall at the discretion of the operator. Patients underwent follow-up with 7-day Holter electrocardiography after 3, 6, and 12 months. Results: A total of 186 patients undergoing a repeat procedure using PFA were included. The median number of previous ablations was 1 (range 1-6). The prior ablation modality was radiofrequency in 129 patients (69.4%), cryoballoon in 51 (27.4%), and epicardial ablation in 6 (3.2%). At the beginning of the procedure, 258 of 744 PVs (35%) showed reconnections. Additional antral ablations were applied in 236 of 486 still isolated veins (49%). Posterior wall ablation was added in 125 patients (67%). Major complications occurred in 1 patient (transient ischemic attack 0.5%). Freedom from arrhythmia recurrence in Kaplan-Meier-analysis was 78% after 6 months and 54% after 12 months. Conclusion: PFA is a versatile and safe option for repeat procedures after failed prior thermal ablation.

Durability of CLOSE-Guided Pulmonary Vein Isolation in Persistent Atrial Fibrillation: A Prospective Remapping Study.

BACKGROUND: Recurrence of paroxysmal atrial fibrillation (AF) following pulmonary vein isolation (PVI) is presumably caused by pulmonary vein (PV) reconnections. However, there is little data available on the durability of PVI and incidence of arrhythmia recurrence in patients with persistent AF. OBJECTIVES: The purpose of this study was to evaluate the lesion durability by means of an a priori planned remapping procedure in patients with persistent AF undergoing CLOSE-guided PVI. METHODS: In a prospective study, we included patients with symptomatic, persistent AF undergoing CLOSE-guided radiofrequency ablation. Irrespective of AF recurrence, a redo procedure was mandated 6 months following the index procedure to evaluate PV reconnections. The outcome of AF ablation was based on clinical recurrence and 7-day Holter electrocardiogram 3 and 6 months after the index procedure and 3, 6, and 12 months after the redo procedure. RESULTS: Of 30 patients included, 26 (81% men; median age 68 years) underwent the planned remapping study a median of 6 months after the index procedure, whereas 4 patients without recurrence refused a repeat procedure. In total, 78 of 102 (76%) PVs showed durable isolation and 15 patients (58%) presented complete isolation of all PVs. Beyond the blanking period, 6 of 26 patients (23%) had arrhythmia recurrence before the redo procedure. Recurrence had occurred in 33% of patients with complete isolation of all veins and in 9% of patients with PV reconnections (P = 0.197). After re-PVI in patients with PV reconnections and additional ablation in patients with recurrence but durable PVI, 17 of 26 patients (65%) were free of arrhythmia after 12 months. CONCLUSIONS: In patients with persistent AF, CLOSE-guided PVI resulted in durable rate of PVI on a per-vein and per-patient level of 76% and 58%, respectively. Arrhythmia recurrence was numerically higher in patients with durable PVI compared with patients without.

Patient characteristics, predictors and outcome of pacemaker patients upgraded to an implantable cardioverter defibrillator.

AIMS: Pacemaker (PM) patients may require a subsequent upgrade to an implantable cardioverter defibrillator (ICD). Limited data exists on this patient population. We sought to characterize this population, to assess predictors for ICD upgrade, and to report the outcome. METHODS: From our prospective PM and ICD implantation registry, all patients who underwent PM and/or ICD implantations at our center were analyzed. Patient characteristics and outcomes of PM patients with subsequent ICD upgrade were compared to age- and sex-matched patients with de novo ICD implantation, and to PM patients without subsequent upgrade. RESULTS: Of 1'301 ICD implantations, 60 (5%) were upgraded from PMs. Median time from PM implantation to ICD upgrade was 2.6 years (IQR 1.3-5.4). Of 2'195 PM patients, 28 patients underwent subsequent ICD upgrades, corresponding to an estimated annual incidence of an ICD upgrade of at least 0.33%. Lower LVEF (p = .05) and male sex (p = .038) were independent predictors for ICD upgrade. Survival without death, transplant and LVAD implantation were worse both for upgraded ICD patients compared to matched patients with de novo ICD implantation (p = .05), as well as for PM patients with subsequent upgrade compared to matched PM patients not requiring an upgrade (p = .036). CONCLUSIONS: One of 20 ICD implantations are upgrade of patients with a PM. At least one of 30 PM patients will require an ICD upgrade in the following 10 years. Predictors for ICD upgrade are male sex and lower LVEF at PM implantation. Upgraded patients have worse outcomes.

Pulsed-field vs cryoballoon vs radiofrequency ablation: Outcomes after pulmonary vein isolation in patients with persistent atrial fibrillation.

BACKGROUND: Pulsed-field ablation (PFA) has shown promising data in terms of safety and procedural efficiency for pulmonary vein isolation (PVI), with similar long-term outcomes compared to radiofrequency ablation (RFA) and cryoballoon ablation (CBA) in patients with paroxysmal atrial fibrillation (AF). OBJECTIVE: The purpose of this study was to compare the procedural and long-term outcomes in patients with persistent AF undergoing PVI using PFA, CBA, or RFA. METHODS: Consecutive patients with persistent AF undergoing first PVI with PFA, CBA, or RFA were included. Patients underwent 7-day Holter electrocardiography at 3, 6, and 12 months postablation. The primary outcome was recurrence of any atrial arrhythmia after a 90-day blanking period. Safety outcomes included the composite of in-hospital major adverse events. RESULTS: A total of 533 patients with persistent AF underwent PVI using PFA (n = 214, 39%), CBA (n = 190, 36%), or RFA (n = 129, 24%). Procedures with PFA guided by fluoroscopy were shorter than those with CBA (median 60 minutes; interquartile range [IQR] 53-80 minutes vs 84 minutes; IQR 68-101 minutes; P ≤ .001), and procedures with PFA in combination with 3-dimensional electroanatomic mapping were shorter than those with RFA (median 101 minutes; IQR 85-126 minutes vs 171 minutes; IQR 141-204 minutes; P < .001). Acute safety events occurred in 2.3%, 2.6%, and 0.8% in the PFA, CBA, and RFA groups, respectively (P = .545). The 1-year confounder-adjusted estimate for freedom from atrial arrhythmias was 62.1% for CBA, 55.3% for PFA, and 48.3% for RFA (CBA vs PFA: P = .79; CBA vs RFA: P = .009; PFA vs RFA: P = .010). CONCLUSION: In patients with persistent AF undergoing first PVI, 1-year confounder-adjusted outcomes are better with PFA and CBA than with RFA.

A Direct-Digital 40 µA 100 kb/s Intracardiac Communication Receiver with 250 µs Startup Time for Low Duty-Cycle Leadless Pacemaker Synchronization.

The first commercial dual-chamber leadless pacemaker (LLPM) was introduced recently. The system combines two separate implants situated in the right atrium and the right ventricle of the heart. Implant synchronization is accomplished with conductive intracardiac communication (CIC) using the myocardium and blood as transmission channel. Successful implant synchronization of this dual-chamber LLPM has been demonstrated. However, the continuously active synchronization transceivers, consuming about 800 nA, cause a 25-45% reduction in the projected device longevity. This work proposes an alternative strategy for power-optimized LLPM synchronization, which is based on synchronous duty-cycling of the transceivers and direct-digital CIC (DD-CIC). In line with this strategy, a novel low-power DD-CIC receiver for short-packet communication based on Manchester-encoded data and with fast startup time is presented. The circuit was fabricated in 180 nm CMOS technology and analyzed with respect to sensitivity, current consumption and startup time under highly duty-cycled operation. The receiver achieves a sensitivity of 81.6±7.4 µV at a data rate of 100 kb/s, with an active current consumption of 39.1±0.6 µA and a startup time below 250 µs. Operating the receiver as specified by the proposed LLPM synchronization strategy reduces the current consumption to a measured average value of 73 nA. In conclusion, this work suggests synchronous duty-cycling for CIC-based implant synchronization as a promising concept to severely reduce the current consumption of contemporary dual-chamber LLPMs. Consequently, device longevity may be increased significantly, potentially reducing the frequency of costly and complication-prone re-interventions.

Impact of atrial fibrillation phenotype and left atrial volume on outcome after pulmonary vein isolation.

AIMS: Pulmonary vein isolation (PVI) is increasingly performed in patients with atrial fibrillation (AF). Both AF phenotype and left atrial (LA) volume have been shown to influence ablation outcome. The inter-relationship of the two is incompletely understood. We aimed to investigate the impact of AF phenotype vs. LA volume on outcome after PVI. METHODS AND RESULTS: In a retrospective analysis of a prospective registry of patients undergoing a first PVI, the association of AF phenotype and LA volume index (LAVI) was assessed as well as their impact on AF recurrence during follow-up. Overall, 476 patients were enrolled (median age 63 years, 29% females, 65.8% paroxysmal AF). Obesity, hypertension, chronic kidney disease, and heart failure were all significantly more frequent in persistent AF. After 1 year, single-procedure, freedom from arrhythmia recurrence was 61.5%. Patients with paroxysmal AF had better outcomes compared with patients with persistent AF (65.6 vs. 52.7%, P = 0.003), as had patients with no/mild vs. moderate/severe LA dilation (LAVI <42 mL/m2 67.1% vs. LAVI ≥42 mL/m2 53%, P < 0.001). The combination of both parameters refined prediction of 1-year recurrence (P < 0.001). After adjustment for additional clinical risk factors in multivariable Cox proportional hazard analysis, both AF phenotype and LAVI ≥42 mL/m2 contributed significantly towards the prediction of 1-year recurrence. CONCLUSION: Atrial fibrillation phenotype and LA volume are independent predictors of outcome after PVI. Persistent AF with no/mild LA dilation has a similar risk of recurrence as paroxysmal AF with a moderate/severe LA dilation and should be given similar priority for ablation.

Electrocardiographic predictors of atrial mechanical sensing in leadless pacemakers.

BACKGROUND: Leadless pacemakers (LPs) capable of VDD pacing allow for atrioventricular synchrony through mechanical sensing of atrial contraction. However, mechanical sensing is less reliable and less predictable than electrical sensing. OBJECTIVE: The purpose of this study was to evaluate P-wave amplitude during sinus rhythm from preoperative 12-lead electrocardiograms (ECGs) as a predictor for atrial mechanical sensing in patients undergoing VDD LP implantation. METHODS: Consecutive patients undergoing VDD LP implantation were included in this 2-center prospective cohort study. ECG parameters were evaluated separately and in combination for association with the signal amplitude of atrial mechanical contraction (A4). RESULTS: Eighty patients (median age 82 years; female 55%; mean body mass index [BMI] 25.8 kg/m2) were included in the study and 61 patients in the A4 signal analysis (19 patients in VVI mode during follow-up). Absolute (aVL, aVF, V1, V2) and BMI-adjusted (I, II, aVL, aVF, aVR, V1, V2) P-wave amplitudes from baseline ECGs demonstrated a statistically significant positive correlation with A4 signal amplitude (all P <.05). A combined P-wave signal amplitude of at least 0.2 mV in V1 and aVL was predictive, with specificity of 83% (95% confidence interval 67%-100%) for A4 signal ≥1 m/s2. We found a significant correlation of A4 signal amplitude and overall atrioventricular synchrony (P = .013). CONCLUSION: P-wave amplitudes in ECG leads aVL and V1 can predict A4 signal amplitude in patients with VDD LP and therefore the probability of successful AV synchronous pacing.

Incidental Arrhythmias During Atrial Fibrillation Screening With Repeat 7-Day Holter ECGs in a Hospital-Based Patient Population.

BACKGROUND: Screening for atrial fibrillation (AF) may reveal incidental arrhythmias of relevance. The aim of this study was to describe incidental arrhythmias detected during screening for AF in the STAR-FIB (Predicting SilenT AtRial FIBrillation in Patients at High Thrombembolic Risk) cohort study. METHODS AND RESULTS: In the STAR-FIB cohort study, we screened hospitalized patients for AF with 3 repeat 7-day Holter ECGs. We analyzed all Holter ECGs for the presence of the following incidental arrhythmias: (1) sinus node dysfunction, defined as sinus pause of ≥3 seconds' duration; (2) second-degree (including Wenckebach) or higher-degree atrioventricular block (AVB); (3) sustained supraventricular tachycardia of ≥30 seconds' duration; and (4) sustained ventricular tachycardia of ≥30 seconds' duration. We furthermore report treatment decisions because of incidental arrhythmias. A total of 2077 Holter ECGs were performed in 794 patients (mean age, 74.7 years; 49% women), resulting in a mean cumulative duration of analyzable ECG signal of 414±136 hours/patient. We found incidental arrhythmias in 94 patients (11.8%). Among these were sinus node dysfunction in 14 patients (1.8%), AVB in 41 (5.2%), supraventricular tachycardia in 42 (5.3%), and ventricular tachycardia in 2 (0.3%). Second-degree AVB was found in 23 patients (2.9%), 2:1 AVB in 10 (1.3%), and complete AVB in 8 (1%). Subsequently, 8 patients underwent pacemaker implantation, 1 for sinus node dysfunction (post-AF conversion pause of 9 seconds) and 7 for advanced AVB. One patient had an implantable cardioverter-defibrillator implanted for syncopal ventricular tachycardia. CONCLUSIONS: Incidental arrhythmias were frequently detected during screening for AF in the STAR-FIB study and resulted in device therapy in 1.1% of our cohort patients.

Epicardial adipose tissue dispersion at CT and recurrent atrial fibrillation after pulmonary vein isolation.

OBJECTIVES: Epicardial adipose tissue (EAT) remodeling is associated with atrial fibrillation (AF). Left atrial (LA) EAT dispersion on cardiac CT is a non-invasive imaging biomarker reflecting EAT heterogeneity. We aimed to investigate the association of LA EAT dispersion with AF recurrence after pulmonary vein isolation (PVI). METHODS: In a prospective registry of consecutive patients undergoing first PVI, mean EAT attenuation values were measured on contrast-enhanced cardiac CT scans in Hounsfield units (HU) within low (- 195 to - 45 HU) and high (- 44 to - 15 HU) threshold EAT compartments around the left atrium (LA). EAT dispersion was defined as the difference between the mean HU values within the two EAT compartments. Continuous variables were compared between groups using the Mann-Whitney U test and cox proportional hazard models were used to calculate hazard ratios of predictors of 1-year AF recurrence. RESULTS: A total of 208 patients were included, 135 with paroxysmal AF and 73 with persistent AF. LA EAT dispersion was significantly larger in patients with persistent compared to paroxysmal AF (52.6 HU vs. 49.9 HU; p = 0.001). After 1 year of follow-up, LA EAT dispersion above the mean (> 50.8 HU) was associated with a higher risk of AF recurrence (HR 2.3, 95% CI 1.5-3.6; p < 0.001). It retained its predictive value when corrected for age, sex, body mass index, LA volume, and AF type (HR 2.8, 95% CI 1.6-4.6; p < 0.001). CONCLUSION: A larger LA EAT dispersion on contrast-enhanced cardiac CT scans, reflecting EAT heterogeneity, is independently associated with AF recurrence after PVI. CLINICAL RELEVANCE STATEMENT: Based on LA EAT dispersion assessment, a more accurate risk stratification and patient selection may be possible based on a pre-procedural cardiac CT when planning PVI. KEY POINTS: • Epicardial adipose tissue (EAT) remodeling is associated with atrial fibrillation (AF). • A larger left atrial EAT dispersion in a pre-procedural cardiac CT was associated with a higher 1-year AF recurrence risk after pulmonary vein isolation. • A pre-procedural cardiac CT with left atrial EAT dispersion assessment may provide a more accurate risk stratification and patient selection for PVI.

Pulsed-field vs. cryoballoon vs. radiofrequency ablation: a propensity score matched comparison of one-year outcomes after pulmonary vein isolation in patients with paroxysmal atrial fibrillation.

BACKGROUND: Pulsed-field ablation (PFA) has shown favourable data in terms of safety and procedural efficiency for pulmonary vein isolation (PVI). We sought to compare procedural and 1-year follow-up data of patients with paroxysmal atrial fibrillation (AF) undergoing PVI using PFA, cryoballoon ablation (CBA) and radiofrequency ablation (RFA). METHODS: Consecutive patients with paroxysmal AF undergoing a first PVI with PFA at our institution were included. For comparison, patients with paroxysmal AF undergoing a first PVI with CBA and RFA were selected using a 1:2:2 propensity score matching. The PFA group followed the standard 32-applications lesion-set protocol, the CBA group a time-to-effect plus 2-min strategy, and the RFA group the CLOSE protocol. Patients were followed with 7d-Holter ECGs 3, 6, and 12 months after ablation. The primary endpoint was recurrence of atrial tachyarrhythmia (ATa) following a blanking period of 3 months. RESULTS: A total of 200 patients were included (PFA n = 40; CBA n = 80; RFA n = 80). Median procedure times were shortest with CBA (75 min) followed by PFA (94 min) and RFA (182 min; p < 0.001). Fluoroscopy dose was lowest with RFA (1.6Gycm2) followed by PFA (5.0Gycm2) and CBA (5.7Gycm2; p < 0.001). After a 1-year follow-up, freedom from ATa recurrence was 85.0% with PFA, 66.2% with CBA and 73.8% with RFA (p = 0.12 PFA vs. CBA; p = 0.27 PFA vs. RFA). CONCLUSION: In a propensity score matched analysis of patients with paroxysmal AF, freedom from any ATa 1 year after PVI using PFA was favourable and at least as good as for PVI with CBA or RFA.

Quality and transparency of evidence for implantable cardiovascular medical devices assessed by the CORE-MD consortium.

BACKGROUND AND AIMS: The European Union Medical Device Regulation 2017/745 challenges key stakeholders to follow transparent and rigorous approaches to the clinical evaluation of medical devices. The purpose of this study is a systematic evaluation of published clinical evidence underlying selected high-risk cardiovascular medical devices before and after market access in the European Union (CE-marking) between 2000 and 2021. METHODS: Pre-specified strategies were applied to identify published studies of prospective design evaluating 71 high-risk cardiovascular devices in seven different classes (bioresorbable coronary scaffolds, left atrial appendage occlusion devices, transcatheter aortic valve implantation systems, transcatheter mitral valve repair/replacement systems, surgical aortic and mitral heart valves, leadless pacemakers, subcutaneous implantable cardioverter-defibrillator). The search time span covered 20 years (2000-21). Details of study design, patient population, intervention(s), and primary outcome(s) were summarized and assessed with respect to timing of the corresponding CE-mark approval. RESULTS: At least one prospective clinical trial was identified for 70% (50/71) of the pre-specified devices. Overall, 473 reports of 308 prospectively designed studies (enrolling 97 886 individuals) were deemed eligible, including 81% (251/308) prospective non-randomized clinical trials (66 186 individuals) and 19% (57/308) randomized clinical trials (31 700 individuals). Pre-registration of the study protocol was available in 49% (150/308) studies, and 16% (48/308) had a peer-reviewed publicly available protocol. Device-related adverse events were evaluated in 82% (253/308) of studies. An outcome adjudication process was reported in 39% (120/308) of the studies. Sample size was larger for randomized in comparison to non-randomized trials (median of 304 vs. 100 individuals, P < .001). No randomized clinical trial published before CE-mark approval for any of the devices was identified. Non-randomized clinical trials were predominantly published after the corresponding CE-mark approval of the device under evaluation (89%, 224/251). Sample sizes were smaller for studies published before (median of 31 individuals) than after (median of 135 individuals) CE-mark approval (P < .001). Clinical trials with larger sample sizes (>50 individuals) and those with longer recruitment periods were more likely to be published after CE-mark approval, and were more frequent during the period 2016-21. CONCLUSIONS: The quantity and quality of publicly available data from prospective clinical investigations across selected categories of cardiovascular devices, before and after CE approval during the period 2000-21, were deemed insufficient. The majority of studies was non-randomized, with increased risk of bias, and performed in small populations without provision of power calculations, and none of the reviewed devices had randomized trial results published prior to CE-mark certification.

Pulmonary vein isolation durability and lesion regression in patients with recurrent arrhythmia after pulsed-field ablation.

BACKGROUND: A novel multipolar pulsed-field ablation (PFA) catheter has recently been introduced for pulmonary vein isolation (PVI). Pre-market data showed high rates for PVI-durability during mandatory remapping studies. OBJECTIVE: To present post-market data in patients with recurrent arrhythmias. METHODS: Consecutive patients undergoing a redo procedure after an index PFA PVI using a bipolar-biphasic PFA system were included. 3-D electro-anatomical maps (3D-EAM) on redo procedure were compared to the 3D-EAM acquired after ablation during the index procedure. PVI durability was assessed on a per-vein and per-patient level and the sites of reconnections were identified. Furthermore, lesion extent around veins with durable isolation was compared to study lesion regression. RESULTS: Of 341 patients treated with a PFA PVI, 29 (8.5%) underwent a left atrial redo ablation due to arrhythmia recurrence. At the end of the index procedure, 110/112 veins (98%, four common ostia) were isolated. On redo procedures performed a median of 6 months after the first ablation, 3D-EAM identified 69/110 (63%) PVs with durable isolation. In 6 (21%) patients, all PVs were durably isolated. Reconnections were more often found on the right-sided veins and on the anterior aspects of the upper veins. Only minor lesion regression was observed between the index and redo procedure (a median of 3 mm (0 - 9.5) on the posterior wall). CONCLUSION: In patients with arrhythmia recurrence after PFA PVI using a first-generation PFA device, durable isolation was observed in 63% of the veins and 21% of the patients showed durable isolation of all previously isolated veins.

A Surface-Integrated Sensor Network for Personalized Multifunctional Catheters.

Augmenting the sensing/actuating capabilities of multifunctional catheters used for minimally invasive interventions has been fostered by the reduction of transducers' sizes. However, increasing the number of transducers to benefit from the entire catheter surface is challenging due to the number of connections and/or the required integrated circuits dedicated for multiplexing the transducer signals. Modular concepts enabling personalized catheters are lacking, at all. In this work, we investigated the feasibility of a simple and daisy-chainable transducer node network for active catheters, which overcomes these limitations. Sequentially accessible nodes enabling analog interaction (including signal buffering) with transducers were designed and fabricated using miniature components suited for catheter integration. The effective sampling rate (ESR) per node for acquiring bio-signals from 10 nodes was examined for various signal-to-noise ratios. Thanks to the low circuit complexity, an ESR up to 20 kHz was achieved, which is high enough for many bio-signals.Clinical relevance- Typical daisy-chaining features, namely theoretically indefinite node extension and simple reconfiguration facilitates modularization of the catheter design. The proposed network consequently ensures application and patient-specific requirements while incorporating transducer functions over the entire catheter surface, both may improve minimally invasive interventions.

Mechanical testing and comparison of porcine tissue, silicones and 3D-printed materials for cardiovascular phantoms.

Background: Cardiovascular phantoms for patient education, pre-operative planning, surgical training, haemodynamic simulation, and device testing may help improve patient care. However, currently used materials may have different mechanical properties compared to biological tissue. Methods/Aim: The aim of this study was to investigate the mechanical properties of 3D-printing and silicone materials in comparison to biological cardiovascular tissues. Uniaxial cyclic tension testing was performed using dumbbell samples from porcine tissue (aorta, pulmonary artery, right and left ventricle). Flexible testing materials included 15 silicone (mixtures) and three 3D-printing materials. The modulus of elasticity was calculated for different deformation ranges. Results: The modulus of elasticity (0%-60%) for the aorta ranged from 0.16 to 0.18 N/mm2, for the pulmonary artery from 0.07 to 0.09 N/mm2, and for the right ventricle as well as the left ventricle short-axis from 0.1 to 0.16 N/mm2. For silicones the range of modulus of elasticity was 0.02-1.16 N/mm2, and for the 3D-printed materials from 0.85 to 1.02 N/mm2. The stress-strain curves of all tissues showed a non-linear behaviour in the cyclic tensile testing, with a distinct toe region, followed by exponential strain hardening behaviour towards the peak elongation. The vessel samples showed a more linear behaviour comparted to myocardial samples. The silicones and 3D printing materials exhibited near-linearity at higher strain ranges, with a decrease in stiffness following the initial deformation. All samples showed a deviation between the loading and unloading curves (hysteresis), and a reduction in peak force over the first few cycles (adaptation effect) at constant deformation. Conclusion: The modulus of elasticity of silicone mixtures is more in agreement to porcine cardiovascular tissues than 3D-printed materials. All synthetic materials showed an almost linear behaviour in the mechanical testing compared to the non-linear behaviour of the biological tissues, probably due to fibre recruitment mechanism in the latter.