Follow-up after PICU discharge for patients with acquired brain injury: the role of an abbreviated neuropsychological evaluation and a return-to-school program.

Objective: To present the results of an abbreviated testing protocol used to screen for neurocognitive and psychological sequelae of critical illness among pediatric intensive care unit (PICU) survivors with acquired brain injury in our post-discharge follow-up programs, and describe our process for facilitating this population's return to academic life. Design: Retrospective cohort study. Setting: Neurocritical care follow-up programs at two U.S. academic, tertiary medical/surgical PICUs. Patients: Children age > 4 years enrolled in the neurocritical care follow-up programs (n=289) at these institutions who underwent neurocognitive and psychological testing between 2017-2021. Interventions: None. Measurements and Main Results: One month after discharge from the hospital, nearly half of the children and/or their parents (48%) in our neurocritical care follow-up programs identified some type of emotional or behavioral concern compared to their premorbid state, and 15% reported some type of cognitive concern. On evaluation, 35% of the children were given a new neurocognitive diagnosis. Neurocognitive domains regulated by the executive functioning system were the most commonly affected, including attention (54%), memory (31%) and processing speed (27%). One-quarter of the children were given a new psychological diagnosis, most commonly post-traumatic stress disorder (PTSD) or stress-related symptoms (12%). Over 80% of patients in the programs were given new recommendations for school, for both new academic services and new classroom accommodations. Over half of children (57%) were referred for comprehensive follow-up neuropsychological evaluation. Conclusions: Abbreviated neurocognitive and psychological evaluation successfully identifies the same deficits commonly found among PICU survivors who undergo longer, more complete testing protocols. When combined with services aimed at successfully re-integrating PICU survivors back to school, this focused evaluation can provide an effective and efficient means of screening for cognitive and emotional deficits among PICU survivors, and establish a rationale for early academic support upon the child's return to school.

Association of genetic variation in telomere-related SNP and telomerase with ventricular arrhythmias in ischemic cardiomyopathy.

BACKGROUND: Telomeres are known to provide genomic stability and telomere length has been associated with cardiovascular diseases. Moreover, a higher telomerase activity has been shown to be associated with ventricular arrhythmias (VA) in ischemic cardiomyopathy. Increasing evidence suggests that genetic variation in key telomere genes has an impact on telomerase activity. Each copy of the minor allele of SNP rs12696304, at a locus including TERC (telomerase), has been associated with ∼75 base pairs reduction in mean telomere length likely mediated by an effect on TERC expression. We investigated the impact of genetic variation of this SNP on telomerase and its association with VA in ischemic cardiomyopathy patients. METHODS AND RESULTS: Ninety ischemic cardiomyopathy patients with primary prevention implantable cardioverter defibrillators (ICDs) were recruited. Thirty-five received appropriate ICD therapy for potentially fatal VA (cases), while the remaining 55 patients did not (controls). No significant differences in baseline demographics were seen between the groups. TS was measured by qPCR, telomerase activity by TRAP assay, and SNP genotyping with Taqman probes. Telomerase was highest in C homozygous allele and had a significant association with VA in this group only (C/C,C/G,G/G; P-value 0.04, 0.33, 0.43). CONCLUSION: The present study is the first to examine the association between telomerase, a SNP at a locus including TERC, and VA in ischemic cardiomyopathy patients. Homozygosity for C-allele significantly effects telomerase expression and its association with VA in this cohort. Large-scale prospective studies are required to determine if this genetic variation predisposes patients to greater arrhythmic tendency post-MI.

Use of a contact force-sensing ablation catheter with advanced catheter location significantly reduces fluoroscopy time and radiation dose in catheter ablation of atrial fibrillation.

AIMS: The aim of this study was to evaluate the 'real-world' impact of a novel contact force (CF)-sensing (SmartTouch™, Biosense Webster, Diamond Bar, CA, USA) catheter coupled with an advanced catheter location (ACL) system on fluoroscopy time and fluoroscopy dose during atrial fibrillation (AF) ablation. METHODS AND RESULTS: This was a retrospective observational cohort study of prospectively collected data of 1515 consecutive patients undergoing paroxysmal AF (PAF) and persistent AF (PerAF) ablation at a single institution between 2009 and 2014. Patients undergoing AF ablation with the SmartTouch catheter and the ACL system (SmartTouch group, n = 510) were compared with those undergoing AF ablation without this technology (control group, n = 1005). The primary outcomes were total fluoroscopy time (min) and fluoroscopy dose as measured by the dose-area product (mGy cm(2)). Secondary endpoints included total procedure time, total ablation time, and major cardiac complications (tamponade, pericardial effusion, and urgent cardiac surgery). The SmartTouch group had significantly lower fluoroscopy times (9.5 vs. 41 min, P < 0.001), radiation doses (1044 vs. 3571 mGy cm(2), P < 0.001), and shorter procedural time (195 vs. 240 min, P < 0.001) when compared with the control group. This was statistically significant for both PAF and PerAF ablations and for both de novo and redo AF procedures. After a learning curve, a median fluoroscopy time of 3.5 min (interquartile range 6) for all AF ablations was achieved. There was no difference in the rate of cardiac complications (∼ 1.5%). CONCLUSION: SmartTouch™ CF-sensing catheter use with ACL™ during AF ablation significantly reduces fluoroscopy times by 77%, radiation dose by 71%, and procedural time by 19% but does not improve overall safety or the risk of cardiac complications.

The lung impedance monitoring in treatment of chronic heart failure (the LIMIT-CHF study).

AIMS: To assess the usefulness of intrathoracic impedance monitoring (IIM) alerts in guiding empirical treatment of chronic heart failure (CHF) patients to prevent heart failure (HF) hospitalizations and unplanned HF care. METHODS AND RESULTS: Chronic heart failure patients with OptiVol or CorVue capable implantable cardioverter-defibrillators were randomized to either the active group (IIM alarm turned on and diuretic dose increased by 50% for 1 week in the event of alarm sounding) or the control group (IIM alarm turned off). The primary endpoint was the number of HF hospitalizations per patient at 1 year. The NYHA class, 6MWT, B-type natriuretic peptide (BNP), and MLWHF questionnaire score were collected at baseline and follow-up. Eighty patients were included and 71 reached 1-year follow-up. There were 1.7 ± 1.5 alerts in the active group and 1.1 ± 1.0 in the control group, P = 0.07. In the active group, 61% of alerts led to a diuretic dose increase. There was a total of 11 HF hospitalizations in the active group vs. 6 in the control group without significant differences in the number of episodes per patient (0.3 ± 0.9 vs. 0.2 ± 0.4, P = 0.95). There were no unplanned HF visits in the active group vs. 0.1 ± 0.3 per patient in the control group, P = 0.08. The total MLWHF scores were significantly increased at the final follow-up in the control group, whereas a trend towards reduction was observed in the active group. CONCLUSION: In this study, an empirical HF treatment guided by IIM alerts did not reduce emergency treatment of HF. However, it seems to have a positive impact on quality of life. CLINICAL TRIAL REGISTRATIONURL: http://www.clinicaltrials.gov. Unique identifier: NCT01320007.

Factors affecting catheter contact in the human left atrium and their impact on ablation efficacy.

INTRODUCTION: Preclinical work suggests factors including catheter orientation and contact consistency during individual radiofrequency ablations influence lesion size. Our aim was to investigate factors affecting catheter contact in the left atrium (LA) and their effects on ablation. METHODS AND RESULTS: A total of 2,298 8-second static LA mapping points were studied in 30 patients undergoing ablation for AF (16 in AF, 14 sinus rhythm [SR], 18 remote robotic navigation [RRN] procedures) using a contact force (CF) sensing catheter. CF variability (CFV: difference between 20 Hz-sampled CF waveform mean peak and trough) increased with mean CF, Spearman's ρ = 0.6, P < 0.005. Catheter drift correlated weakly with CF (Pearson's correlation -0.06, P = 0.005). CFV was higher in SR than AF and with RRN (P < 0.001). In AF, there was less catheter drift for RRN than manual navigation points but the converse was true in SR. In 747 static 30 second LA ablations, the influence of contact parameters on ablation efficacy was compared by multivariate analysis of impedance drop during ablation: a lesser drop suggesting reduced efficacy. For a given force time integral (FTI), increased CFV (>5 g) and locational drift (>3.5 mm), perpendicular contact, SR and RRN usage were associated with a lesser impedance drop with ablation (P < 0.005 for each), suggesting reduced efficacy. CONCLUSIONS: Beyond the FTI, the quality of catheter contact influences ablation efficacy, and clinical catheter contact is affected by multiple factors, including the atrial rhythm and catheter navigation mode. Maximal efficacy is provided by parallel contact with CFV ≤5 g, catheter drift ≤3.5 mm, and manual navigation.

Point-by-Point Radiofrequency Ablation Versus the Cryoballoon or a Novel Combined Approach: A Randomized Trial Comparing 3 Methods of Pulmonary Vein Isolation for Paroxysmal Atrial Fibrillation (The Cryo Versus RF Trial).

INTRODUCTION: Catheter ablation of paroxysmal AF using the Cryoballoon (CRYO) has yielded similar success rates to conventional wide encirclement using radiofrequency catheter ablation (RFCA), but randomized data are lacking. Pilot data suggested a high success rate with a combined approach (COMBINED) using wide encirclement with RFCA followed by 2 CRYO applications to each vein. We compared these 3 strategies in a randomized controlled trial. METHODS AND RESULTS: Patients undergoing first time paroxysmal AF ablation were randomized to RFCA, CRYO, or COMBINED. Patients were followed up at 3, 6, and 12 months with 7 days of ambulatory ECG monitoring. Success was defined as freedom from arrhythmia without antiarrhythmic drugs after a single procedure. A total of 237 patients were randomized. Success at 1 year was achieved in 47% in the RFCA group, 67% in the CRYO group, and 76% in the COMBINED group (P < 0.001 for RFCA vs. CRYO, P<0.001 for RFCA vs. COMBINED, and P = 0.220 for CRYO vs. COMBINED). Procedure time was 211 (IQR 174-256) minutes for RFCA compared to 167 (136-202) minutes for CRYO and 278 (243-327) minutes for COMBINED (P < 0.001 for RFCA vs. COMBINED, RFCA vs. CRYO, and CRYO vs. COMBINED groups). CONCLUSIONS: Pulmonary vein isolation for paroxysmal AF is faster with CRYO and results in a higher single procedure success rate than conventional point by point RFCA. The COMBINED approach was not superior to CRYO alone.

Diagnostic accuracy of cardiac magnetic resonance imaging in the detection and characterization of left atrial catheter ablation lesions: a multicenter experience.

INTRODUCTION: We tested the hypothesis that cardiovascular magnetic resonance (CMR) imaging can reliably distinguish the presence or absence of left atrial (LA) ablation lesions by blinded analysis of pre- and postablation imaging. METHODS: Consecutive patients at 2 centers undergoing pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation by either wide area circumferential radiofrequency ablation (WACA) or ostial ablation with a cryoballoon underwent CMR late gadolinium enhancement (LGE) imaging pre- and 3 months postablation. Imaging was anonymized for blinded analysis of (1) LGE images, and (2) a 3D fusion image with LGE projected onto a segmented LA surface. Scans were categorized using both assessment techniques separately as pre- or postablation, and if postablation, whether lesions were in an ostial or WACA distribution. RESULTS: LGE imaging was performed in 50 patients (aged 60 ± 10 years, 68% male, 24 underwent WACA and 26 had cryoablation). Sensitivity and specificity for detection of ablation lesions was 60% and 96% on LGE imaging. Sensitivity was higher using 3D fusion imaging (88%; P = 0.003). The proportion in whom lesions were both detected and the distribution correctly assessed as WACA or ostial was higher with 3D fusion imaging compared to LGE imaging (54% vs 28%; P = 0.014). There was no difference in the detection of radiofrequency ablation lesions compared to cryoablation lesions (58% vs 62%; P = 1.000). CONCLUSION: LGE imaging of atrial scar is not yet sufficiently accurate to reliably identify ablation lesions or to determine lesion distribution.

Long-term outcomes following catheter ablation versus medical therapy in patients with persistent atrial fibrillation and heart failure with reduced ejection fraction.

AIMS: The ARC-HF and CAMTAF trials randomized patients with persistent atrial fibrillation (AF) and heart failure (HF) to early routine catheter ablation (ER-CA) versus pharmacological rate control (RC). After trial completion, delayed selective catheter ablation (DS-CA) was performed where clinically indicated in the RC group. We hypothesized that ER-CA would result in a lower risk of cardiovascular hospitalization and death versus DS-CA in this population. METHODS AND RESULTS: Overall, 102 patients were randomized (age 60 ± 11 years, left ventricular ejection fraction [LVEF] 31 ± 11%): 52 to ER-CA and 50 to RC. After 12 months, patients undergoing ER-CA had improved self-reported symptom scores, lower New York Heart Association class (i.e. better functional capacity), and higher LVEF compared to patients receiving RC alone. During a median follow-up of 7.8 (interquartile range 3.9-9.9) years, 27 (54%) patients in the RC group underwent DS-CA and 34 (33.3%) patients died, including 17 (32.7%) randomized to ER-CA and 17 (34.0%) randomized to RC. Compared with DS-CA, a strategy of ER-CA exhibited similar risk of all-cause mortality (adjusted hazard ratio [aHR] 0.89, 95% confidence interval [CI] 0.44-1.77, p = 0.731) and combined all-cause mortality or cardiovascular hospitalization (aHR 0.80, 95% CI 0.43-1.47, p = 0.467). However, analyses according to treatment received suggested an association between CA and improved outcomes versus RC (all-cause mortality: aHR 0.43, 95% CI 0.20-0.91, p = 0.028; all-cause mortality/cardiovascular hospitalization: aHR 0.48, 95% CI 0.24-0.94, p = 0.031). CONCLUSIONS: In patients with persistent AF and HF, ER-CA produces similar long-term outcomes to a DS-CA strategy. The association between CA as a treatment received and improved outcomes means there is still a lack of clarity regarding the role of early CA in selected patients. Randomized trials are needed to clarify this question.

Improved electrogram attenuation during ablation of paroxysmal atrial fibrillation with the Hansen robotic system.

BACKGROUND: Robotic catheter ablation aims to improve outcomes after ablation of atrial fibrillation (AF) through improved lesion quality. This study examined electrogram attenuation as a measure of efficacy in response to robotic (ROB) and manual (MAN) ablation. METHODS: Patients with paroxysmal AF undergoing ablation as part of an ongoing randomized controlled trial were studied (Clinical Trials Registration NCT01037296). Patients underwent pulmonary vein isolation using NavX (St. Jude Medical, St. Paul, MN, USA). Patients were randomized to MAN or ROB catheter ablation using a 3.5-mm irrigated-tip catheter with standardized ablation settings. Bipolar electrogram voltage was measured at 0, 5, 10, 20, and 30 seconds after ablation onset. Distance from ablation lesion to the left atrial surface on NavX were calculated. RESULTS: Similar ablation energy was delivered in ROB and MAN groups, achieving comparable rates of PV isolation (100% vs 98%). The bipolar voltages of 4,434 electrograms from 303 ablation lesions (146 ROB, 157 MAN) were measured. At 30 seconds, signal attenuation was greater in the ROB group than MAN (mean 65 ± 4% vs 55 ± 4% of baseline voltage, P < 0.01). A total of 2,064 NavX ablation lesions were assessed (906 ROB and 1,158 MAN). ROB lesions were on average 0.52 mm further inside the geometry than MAN (P < 0.0001). CONCLUSIONS: Robotic ablation results in greater signal attenuation in man. This is achieved despite manual lesions being closer to the left atrial surface. Catheter stability and constant energy delivery may be key to achieving signal attenuation, rather than increased contact force.

Pulmonary vein isolation with radiofrequency ablation followed by cryotherapy: a novel strategy to improve clinical outcomes following catheter ablation of paroxysmal atrial fibrillation.

INTRODUCTION: Pulmonary vein (PV) isolation for atrial fibrillation (AF) often requires repeat procedures due to PV reconnection. We hypothesized that wide area cicumferential ablation using radiofrequency energy (RFA) followed by ostial PV ablation with a cryoablation balloon would reduce the rate of AF recurrence compared with either approach alone. METHODS AND RESULTS: A retrospective study compared outcomes in the first 25 consecutive patients undergoing PV isolation for paroxysmal AF using the combined approach, to consecutive controls using either approach alone. Demographic and procedural data were collected from a prospective database. Kaplan-Meier curves were used to analyse AF free survival and curves were compared using the log-rank test. Twenty-five patients were included in each group. There were no major complications. Minor complications included two transient phrenic nerve palsies and a haematoma in both the combined groups and the cryoablation alone groups. In the RFA group the only complication was a grounding plate burn. Follow-up was 2.2 years in the RFA group, 1.0 years in the cryoablation group, and 1.4 years in the combined group. All recurrences but one occurred within one year. Freedom from AF was significantly greater in the combined group (80%) compared with the RFA alone group (52%) and the cryoablation alone group (56%, both P < 0.05). CONCLUSION: The combined approach was safe and increased single procedure efficacy of PV isolation for AF compared with either technique alone.

Impact of variant pulmonary vein anatomy and image integration on long-term outcome after catheter ablation for atrial fibrillation.

AIMS: To investigate the impact of variant pulmonary vein (PV) anatomy and the use of three-dimensional image integration (3D-II) on long-term efficacy of catheter ablation for atrial fibrillation (AF). METHODS: Consecutive procedures from 2002 to 2007 were analysed from a prospective database. All patients underwent wide area circumferential ablation, with linear lesions added and complex fractionated electrograms targeted for persistent AF. Imaging was segmented on Carto to assess PV anatomy. RESULTS: Three hundred and fifty patients underwent 1.9 ± 0.9 procedures. The mean age was 57 ± 11 years, 73% males, and 55% paroxysmal AF. Freedom from AF/atrial tachycardia was 42% for paroxysmal AF and 20% for persistent AF at 3.1 years after the first procedure, or 86 and 66%, respectively, at 2.5 years after the last procedure. The Kaplan-Meier analysis showed a trend towards improved single-procedure efficacy with 3D-II (8.9% difference, P = 0.087) and a reduction in the number of procedures per patient from 2.1 ± 1.1 to 1.8 ± 0.9 (P < 0.0001). The use of 3D-II improved single-procedure efficacy with Carto (13.3% difference, P = 0.018), but not with Ensite NavX. Variant PV anatomy was identified in 28% and was associated with a lower single-procedure efficacy (10.0% difference, P = 0.024) but with no effect on final outcome. Multivariate analysis confirmed the impact of 3D-II [hazard ratio (HR) for recurrence of AF 0.67, P = 0.020] and variant PV anatomy (HR 1.37, P = 0.044). CONCLUSION: The use of 3D-II improves single-procedure efficacy of PV isolation for AF. Variant PV anatomy was associated with a lower single-procedure success rate.

Learning from domestic homicide reviews in England and Wales.

This paper aims to contribute to the prevention of future domestic homicide by analysing 141 domestic homicide reviews (DHRs) in England and Wales. All publicly available DHRs (n = 141) were retrieved from Community Safety Partnership websites in England and Wales in June 2016. Utilising a mixed methods approach, we designed templates to extract quantitative and qualitative data from DHRs. Descriptive statistics were generated by SPSS. 54 DHRs were analysed qualitatively, using N-Vivo for data management. The findings revealed that perpetrators were aged: 16-82 years; with a mean average age of 41 years. Victims' ages ranged from 17 to 91 years old; with a mean average age: 45 years. Perpetrators' mental health was mentioned in 65% of DHRs; 49% of perpetrators had a mental health diagnosis. Healthcare services, in particular, mental health services, were most likely to be involved with perpetrators. 'Movement' was identified as a key contextual feature of the 54 DHRs analysed qualitatively and this was found to interact with risk assessment, language barriers and housing problems. In conclusion, domestic violence and abuse risk assessments need to be informed by the knowledge that domestic abuse occurs across the age span. Mental health settings offer an opportunity for intervention to prevent domestic homicide. Domestic Homicide Reviews can provide valuable material for training practitioners.

A randomized-controlled trial comparing conventional with minimal catheter approaches for the mapping and ablation of regular supraventricular tachycardias.

AIMS: To compare the use of a minimal (MIN) with a conventional (CON) catheter approach for the mapping and ablation of regular supraventricular tachycardias (SVT) and typical atrial flutter (AFL) in the setting of a randomized-controlled trial. METHODS AND RESULTS: Two hundred patients (age 51.2 +/- 15.9 years, 99 male) were randomized to a MIN or CON group. The MIN approach involved using two catheters for AFL, one to three for other SVT (ablation catheter included), whereas the CON approach involved three and five catheters, respectively. Acute procedural success was similar between the two groups. There was no significant difference in overall procedure times, fluoroscopy times, or radiation doses. Procedure times were shorter for AFL ablation in MIN compared with CON [60 (30-150) vs. 85 (40-200) min, median (range), P = 0.03] from subgroup analysis. A median of three (one to six) catheters was used in MIN and five (three to seven) in CON (P < 0.0001). Catheter costs were significantly lower in MIN compared with CON [6.1 (2-61) vs. 8.5 (4.4-21.3) units, P < 0.0001, where one unit is equivalent to the cost of a diagnostic quadripolar catheter]. At 6-week follow-up, two patients in MIN (2.1%) and three patients in CON (3.2%) had documented recurrence of the index arrhythmia. CONCLUSION: The use of a MIN approach in the treatment of SVT and AFL is as effective, quick, and safe as using a CON approach and is therefore more cost-effective.

A randomized trial to compare atrial fibrillation ablation using a steerable vs. a non-steerable sheath.

AIMS: Catheter positioning and stability are recognized challenges in catheter ablation of atrial fibrillation (AF). This prospective randomized study assessed whether routinely using a steerable sheath affects procedure outcomes. METHODS AND RESULTS: Fifty-six AF patients were randomized to ablation using either an Agilis NXT (St Jude Medical, St Paul, MN, USA) steerable sheath or a fixed-curve Mullins sheath (Cook Medical Inc., Bloomington, IN, USA) for the ablation catheter. A mapping system with CT integration was used to isolate the pulmonary veins (PVs) in pairs and further ablation performed if AF persisted. There was no significant difference in time to gain trans-septal access, CT registration time, time to isolate PVs, fluoroscopy time for PV isolation, total procedure time, or total fluoroscopy time. A learning curve was seen for the steerable sheath, and after correcting for this, CT registration time and right PV isolation were quicker in this group. One patient crossed over from fixed-curve to steerable. Acute, 3-, and 6-month single procedure success were similar in both groups. CONCLUSION: Allowing for the usage learning curve, a steerable sheath reduced time for some elements of AF ablation. Although this did not result in improved success, it may be useful for inexperienced operators, but at increased procedure cost.

Task Performance and Meta-Cognitive Outcomes When Using Activity Workstations and Traditional Desks.

The purpose of the current study is to compare the effects of light physical activity to sedentary behavior on cognitive task performance and meta-cognitive responses. Thirty-eight undergraduate students participated in the study. The participants used a stationary bicycle with a desk top and a traditional desk while completing two complex cognitive tasks and measures of affect, motivation, morale, and engagement. The participants pedaled the stationary bicycle at a slow pace (similar in exertion to a normal walking pace) while working. The results indicated that cognitive task performance did not change between the two workstations. However, positive affect, motivation, and morale improved when using the stationary bicycle. These results suggest that activity workstations could be implemented in the work place and in educational settings to help decrease sedentary behavior without negatively affecting performance. Furthermore, individuals could experience a positive emotional response when working on activity workstations which in turn could help encourage individuals to choose to be more physical active during daily activities.

Developmental validation of the PowerPlex(®) Fusion 6C System.

The PowerPlex(®) Fusion 6C System is a 27-locus, six-dye, multiplex that includes all markers in the expanded CODIS core loci and increases overlap with STR database standards throughout the world. Additionally, it contains two, rapidly mutating, Y-STRs and is capable of both casework and database workflows, including direct amplification. A multi-laboratory developmental validation study was performed on the PowerPlex(®) Fusion 6C System. Here, we report the results of that study which followed SWGDAM guidelines and includes data for: species specificity, sensitivity, stability, precision, reproducibility and repeatability, case-type samples, concordance, stutter, DNA mixtures, and PCR-based procedures. Where appropriate we report data from both extracted DNA samples and direct amplification samples from various substrates and collection devices. Samples from all studies were separated on both Applied Biosystems 3500 series and 6-dye capable 3130 series Genetic Analyzers and data is reported for each. Together, the data validate the design and demonstrate the performance of the PowerPlex(®) Fusion 6C System.

Impact of Catheter Contact Force on Human Left Atrial Electrogram Characteristics in Sinus Rhythm and Atrial Fibrillation.

BACKGROUND: During left atrial mapping, optimal contact parameters minimizing variation secondary to catheter contact are not established. METHODS AND RESULTS: Across 30 patients undergoing first-time atrial fibrillation ablation, 1965 stable mapping points (1409 atrial fibrillation, 556 sinus rhythm), comprising 8-s contact force (CF) and bipolar electrogram data were analyzed. Points were taken in groups at locations with CF or catheter orientation actively changed between acquisitions. Complexes were less positive at higher CF (Spearman ρ, -0.2; P<0.005, both rhythms). Increasing CF at a location significantly increased complex size, but only where initial CF was <10 g, and if the change was ≥4.5 g in sinus rhythm and ≥8 g in atrial fibrillation (P<0.0005, both rhythms): if initial CF was ≥10 g, no change was observed, regardless of CF change (P>0.05, both). Atrial ectopics during sinus rhythm were observed more frequently when CF was ≥10 g (P<0.0005). Increasing CF at a location was associated with an increase in the complex fractionated atrial electrogram interval confidence level score, but only if initial CF was <10 g and CF increased ≥8 g (P=0.003). The dominant frequency and organization index were unaffected by CF (P>0.1 for both). Changing catheter orientation from perpendicular to parallel in atrial fibrillation was associated with smaller, more positive complexes (P=0.001 for both), but no changes in complex fractionated atrial electrogram scores, dominant frequency or organization index (P>0.08 for each). CONCLUSIONS: During left atrial electrogram mapping, including complex fractionated atrial electrogram but not spectral parameter mapping, CF and catheter orientation influence results: consequently, mapping CFs should be ≥10 g to negate the influence of CF. CLINICAL TRIALS REGISTRATION: URL: http://clinicaltrials.gov/. Unique identifier: NCT01587404.

Pulmonary vein measurements on pre-procedural CT/MR imaging can predict difficult pulmonary vein isolation and phrenic nerve injury during cryoballoon ablation for paroxysmal atrial fibrillation.

OBJECTIVE: We tested the hypothesis that pulmonary vein (PV) measurements on pre-procedural CT/MR imaging can predict difficulty in isolation and phrenic nerve (PN) injury during cryoballoon ablation for paroxysmal atrial fibrillation (AF). METHODS: Consecutive patients with paroxysmal AF who had pre-procedural CT/MRI and underwent cryoballoon ablation as part of a randomized trial were studied. Imaging was anonymized for blinded analysis of: (1) maximum ostial diameter, (2) minimum ostial diameter, (3) ostial area and (4) ratio of maximum over minimum ostial diameter (eccentricity index). Veins that required more than 2 freezes of at least 200 s duration to isolate or not isolated were defined as difficult to isolate. Loss of PN pacing during right-sided ablation was defined as PN injury. Logistic regression was used to analyze the predictive effect of the measurements on the 2 outcomes. RESULTS: 148 PVs in 38 patients (aged 60 ± 11 years, 76% male) were analyzed. Left inferior PV (LIPV) was most difficult to isolate with 23 out of 37 PVs (62%), and PN injury occurred in 3 of 38 (8%) right superior PV (RSPV). Greater eccentricity index predicted difficulty in isolating LIPV, OR 40.33 (95% CI 1.40 to 1160, p = 0.03) and smaller eccentricity index predicted PN injury in RSPV, OR 0.01 (95% CI 0.01-0.16, p = 0.001). CONCLUSIONS: Eccentricity index measured from pre-procedural CT/MR imaging can predict difficulty of PV isolation and PN injury during cryoballoon ablation for paroxysmal AF.

Randomized trial comparing robotic to manual ablation for atrial fibrillation.

BACKGROUND: Catheter ablation of atrial fibrillation (AF) is a physically demanding procedure for the operator, involving radiation exposure, and has limited success rates. Remote robotic navigation (RRN) may offer benefit to the procedure, though only 1 previous small randomized trial has assessed this. OBJECTIVE: This study aimed to investigate the impact of RRN on 1-year single-procedure success rates. METHODS: RRN was compared to manual ablation in a randomized control trial setting by using an intention-to-treat analysis. RESULTS: A total of 157 patients underwent ablation (116/157 (74%) persistent AF; 67/116 (58%) of these long-standing persistent AF). There were no significant differences between the RRN and manual groups with respect to 1-year single-procedure success rates (19/78 (24%) and 26/78 (33%), respectively; P = .29), acute wide area circumferential ablation reconnection rates, complication rates, or procedure times. On multivariable analysis, fluoroscopy times were significantly shorter in the RRN group. The number of catheter displacements during ablation was lower in the RRN group, as was subjectively assessed operator fatigue. The crossover rate from RRN to manual ablation was 11/78 (14%), mainly secondary to technical problems with the RRN system. A learning curve was evident for RRN ablation: the fluoroscopy and procedure times were significantly lower after the first 10 cases in an operator's experience. CONCLUSION: This randomized trial showed no difference in the success rate for catheter ablation of AF between a RRN and manual approach. The results highlight the learning curve for RRN ablation and suggest that the use of this technology leads to an improvement in fluoroscopy times, catheter stability, and operator fatigue.

Target indices for clinical ablation in atrial fibrillation: insights from contact force, electrogram, and biophysical parameter analysis.

BACKGROUND: In animal studies of radiofrequency ablation, lesion sizes plateau as the maximum lesion size is reached for an ablation. Lesion parameters are not available in clinical ablations, but preclinical work suggests that these correlate with impedance drop and electrogram attenuation. Characterization of the relationships between catheter contact force, ablation duration, and these surrogate markers of lesion formation may allow us to define targets for effective ablation. METHODS AND RESULTS: Fifteen patients undergoing first-time radiofrequency ablation for nonparoxysmal atrial fibrillation were studied. All were in atrial fibrillation at the time of the procedure. Ablations were performed with an irrigated-tip contact force-sensing catheter in temperature-controlled mode (temperature limited to 48°C, power to 30 W). Included were 285 left atrial static ablations, 247 with additional impedance data. The ablation force time integral (FTI) correlated with the attenuation of the electrogram with ablation (Spearman ρ, -0.14; P=0.02): the relationship plateauing from 500 g·s, a reduction in the electrogram amplitude of 20%. The FTI also correlated with the impedance drop during ablation (Spearman ρ, 0.79; P<0.0005): the relationship was logarithmic, the reduction in the impedance with an increasing FTI also plateauing from 500 g·s, an impedance drop of 7.5%. The ablation duration affected the impedance drop at an FTI if the duration was <10 s. Beyond this time point, the FTI achieved rather than the ablation duration or mean contact force applied determined the impedance drop. CONCLUSIONS: During nonparoxysmal atrial fibrillation ablation, an FTI of 500 g·s should be targeted with ablation duration of ≥10 s. Clinical Trials Registration- URL: http://clinicaltrials.gov/. Unique Identifier: NCT01587404.