A retrospective analysis of frailty status on atrial fibrillation catheter ablation outcomes.

INTRODUCTION: Catheter ablation for atrial fibrillation (AF) reduces symptoms and improves the quality of life compared with medical treatment. It is unclear if frailty impacts on the outcome of catheter ablation in patients with symptomatic AF. We sought to evaluate the association between frailty as measured by the validated NHS electronic Frailty Index (eFI) and outcomes post-AF ablation. METHODS: Two hundred forty eight patients who had undergone AF ablation with a mean age of 72.9 ± 5.16 were included in the study retrospectively. The primary endpoint for success was defined as freedom from atrial arrhythmia lasting >30 s beyond the 3-month blanking periods. Frailty was based on the eFI, and the cohort split into four groups: fit (no frailty), mild, moderate and severe frailty. RESULTS: Frailty was categorized as fit (118/248; 47.6%), mild (66/248; 26.6%), moderate (54/248; 21.8%), and severe (10/248; 4.0%). Freedom from arrhythmia occurred in 167 of 248 (67.3%) patients after a mean follow-up of 25.8 +/- 17.3 months. Fit patients had significantly greater freedom from arrhythmia (92/118; 78%) compared to mild frailty (40/66; 60.6%, p-value = .020), moderate frailty (31/54; 57.4%, p-value = .006), or severe frailty (4/10; 40.0%, p-value < .001). There was also a significant difference in arrhythmia occurrence between patients with mild frailty and severe frailty (p-value = .044). CONCLUSION: Frailty is associated with poorer outcomes in patients undergoing AF ablation. The eFI may be used in the prognostic evaluation of AF ablation outcomes. Further studies are essential to confirm the findings of this study.

Long Term outcomes of percutaneous atrial fibrillation ablation in patients with continuous monitoring.

INTRODUCTION: There is limited data using continuous monitoring to assess outcomes of atrial fibrillation (AF) ablation. This study assessed long-term outcomes of AF ablation in patients with implantable cardiac devices. METHODS: 207 patients (mean age 68.1 ± 9.5, 50.3% men) undergoing ablation for symptomatic AF were followed up for a mean period of 924.5 ± 636.7 days. Techniques included The Pulmonary Vein Ablation Catheter (PVAC) (59.4%), cryoablation (17.4%), point by point (14.0%) and The Novel Irrigated Multipolar Radiofrequency Ablation Catheter (nMARQ) (9.2%). RESULTS: 130 (62.8%) patients had paroxysmal AF (PAF) and 77 (37.2%) persistent AF. First ablation and repeat ablation reduced AF burden significantly (relative risk 0.91, [95% CI 0.89 to 0.94]; P <0.0001 and 0.90, [95% CI, 0.86-0.94]; P <0.0001). Median AF burden in PAF patients reduced from 1.05% (interquartile range [IQR], 0.1%-8.70%) to 0.10% ([IQR], 0%-2.28%) at one year and this was maintained out to four-years. Persistent AF burden reduced from 99.9% ([IQR], 51.53%-100%) to 0.30% ([IQR], 0%-77.25%) at one year increasing to 87.3% ([IQR], 4.25%-100%) after four years. If a second ablation was required, point-by-point ablation achieved greater reduction in AF burden (relative risk, 0.77 [95% CI, 0.65-0.91]; P <0.01). CONCLUSION: Ablation reduces AF burden both acutely and in the long-term. If a second ablation was required the point-by-point technique achieved greater reductions in AF burden than "single-shot" technologies. Persistent AF burden increased to near pre ablation levels by year 4 suggesting a different mechanism from PAF patients where this increase did not occur.

How many patients with heart failure are eligible for cardiac contractility modulation therapy?

BACKGROUND: Increasing evidence exists suggesting that cardiac contractility modulation therapy (CCM) improves symptoms in heart failure patients if various selection criteria are fulfilled. The aim of this study is to analyse an unselected sample of heart failure patients to establish what percentage of patients would meet the current criteria for CCM therapy. METHODS: All patients admitted to two district general hospitals in the UK in 2018 with a diagnosis of heart failure were audited for eligibility for CCM therapy. The selection criteria were (a) ejection fraction (EF) 25%-45%, (b) QRS duration less than 130 ms, (c) New York Heart Association (NYHA) class 3-4 and (d) treated for heart failure for at least 90 days and on stable medications. Exclusion criteria included: (a) significant valvular disease, (b) permanent or persistent atrial fibrillation, (c) biventricular pacing system implanted or QRS duration more than 130 ms and (4) patients not suitable for device therapy as a result of palliative treatment intent. RESULTS: A total of 475 patients were admitted with heart failure during the study period. From this group, 24 (5.1%) patients fulfilled the criteria for CCM therapy. The mean age and ejection fraction were 70.8 ± 10.2 and 32.5% ± 7.4%. The majority of patients were men (71%) and had an ischaemic cardiomyopathy (75%). If patients with atrial fibrillation were included, an additional 18 (3.8%) patients potentially may be eligible for CCM. CONCLUSION: Only 5.1% of all patients presenting with heart failure might benefit from cardiac CCM. This is a small proportion of the overall heart failure population. However, this population has no other current option for device therapy of their condition.

The long-term effect of thermal-guided second-generation cryoablation in paroxysmal and persistent atrial fibrillation.

BACKGROUND: Second-generation cryoballoon ablation is safe and effective in patients with paroxysmal (PAF) and persistent atrial fibrillation (AF). OBJECTIVE: This study aimed to assess the long-term clinical outcomes and freedom from AF in patients undergoing thermal-guided cryoablation without the use of an electrical mapping catheter. METHODS: All patients who had undergone thermal-guided second-generation cryoablation without electrical mapping between January 2015 and April 2018 at Eastbourne District General Hospital were retrospectively analysed. Success was defined as freedom from atrial arrhythmia lasting >30 s during the follow up period. RESULTS: The study included 234 patients with a mean age of 65.3 ± 10.6 years. There were 134 (57.0%) and 100 (42.7%) patients who had PAF and persistent AF respectively. Arrhythmia recurrence occurred in 38 of 134 (28.4%) PAF and 42 of 100 (42.0%) persistent AF patients after mean follow up of 40 ± 9.2 months. The patients with PAF had a significantly greater freedom from arrhythmia than patients with persistent AF (p = .040). The mean procedure time was 55.5 ± 12.2 min and the mean fluoroscopy time was 10.9 ± 4.8 min 73.5% of patients were discharged on the same day. CONCLUSION: Thermal-guided cryoablation is feasible, safe and results in freedom from arrhythmia in the majority of paroxysmal and persistent AF patients in the long term. Randomised controlled trials are required to confirm the findings of this study.

Central arteriovenous anastomosis for the treatment of patients with uncontrolled hypertension and paroxysmal AF.

A central iliac arteriovenous anastomosis, the 'coupler' (ROX Medical, California, USA) results in a significant reduction in blood pressure in hypertensive patients. This study assessed the change in AF burden following coupler implantation in patients with paroxysmal AF (PAF) and hypertension. Good blood pressure control using the coupler results in a significant reduction in AF burden.

Atrial high-rate episodes: prevalence, stroke risk, implications for management, and clinical gaps in evidence.

Self-terminating atrial arrhythmias are commonly detected on continuous rhythm monitoring, e.g. by pacemakers or defibrillators. It is unclear whether the presence of these arrhythmias has therapeutic consequences. We sought to summarize evidence on the prevalence of atrial high-rate episodes (AHREs) and their impact on risk of stroke. We performed a comprehensive, tabulated review of published literature on the prevalence of AHRE. In patients with AHRE, but without atrial fibrillation (AF), we reviewed the stroke risk and the potential risk/benefit of oral anticoagulation. Atrial high-rate episodes are found in 10-30% of AF-free patients. Presence of AHRE slightly increases stroke risk (0.8% to 1%/year) compared with patients without AHRE. Atrial high-rate episode of longer duration (e.g. those >24 h) could be associated with a higher stroke risk. Oral anticoagulation has the potential to reduce stroke risk in patients with AHRE but is associated with a rate of major bleeding of 2%/year. Oral anticoagulation is not effective in patients with heart failure or survivors of a stroke without AF. It remains unclear whether anticoagulation is effective and safe in patients with AHRE. Atrial high-rate episodes are common and confer a slight increase in stroke risk. There is true equipoise on the best way to reduce stroke risk in patients with AHRE. Two ongoing trials (NOAH-AFNET 6 and ARTESiA) will provide much-needed information on the effectiveness and safety of oral anticoagulation using non-vitamin K antagonist oral anticoagulants in patients with AHRE.

A trial of three non-invasive blood pressure monitors compared with invasive blood pressure assessment in atrial fibrillation and sinus rhythm.

OBJECTIVE: To investigate the accuracy of three non-invasive blood pressure (BP) devices in atrial fibrillation (AF) compared with invasive arterial BP. METHODS: One hundred patients aged 45-90 years, 63% male (50 in AF and 50 age matched controls in sinus rhythm [SR]) were identified with arterial lines measuring beat-to-beat BP fluctuation. Non-invasive BP measurements utilising the manual sphygmomanometer (MS), PulseCor R6.5 (PC) and automated sphygmomanometer (AS) were taken simultaneously with invasive BP in a randomised sequence. This was repeated three times in each patient. RESULTS: In SR differences in systolic BP (SBP) for MS, AS and PC were -0.34 mm Hg (95% CI -2.31 to 1.63; P = .733), -3.80 mm Hg (95% CI -5.73 to -1.87; P = .0001) and -3.90 mm Hg (95% CI -5.90 to -1.90; P = .0001) and for diastolic BP (DBP) were 6.02 mm Hg (95% CI 4.39-7.64; P < .0001), 8.95 mm Hg (95% CI 7.36-10.55; P < .0001) and 7.54 mm Hg (95% CI 5.89-9.18; P < .0001), respectively. In AF mean differences in SBP for MS, AS and PC were -7.33 mm Hg (95% CI -9.11 to -5.55; P < .0001), -5.29 mm Hg (95% CI -7.08 to -3.50; P < .0001) and -5.75 mm Hg (95% CI -7.54 to -3.96; P < .0001) respectively and for DBP were 5.28 mm Hg (95% CI 4.03-6.54; P < .0001), 6.26 mm Hg (95% CI 5.00-7.52; P < .0001) and 6.89 mm Hg (95% CI 5.64-8.15; P < .0001) respectively. CONCLUSIONS: The MS is accurate in SR because of direct assessment of Korotkoff sounds. Non-invasive BP assessment in AF is significantly less accurate. These findings have important prognostic and therapeutic implications.

Results of the first investigator-initiated randomized clinical trial of nMARQTM, PVACTM, and thoracoscopic ablation for paroxysmal atrial fibrillation.

Aims: To investigate the effect of minimally invasive thoracoscopic surgical ablation and nMARQ irrigated multi-electrode phased radiofrequency (RF) ablation to treat paroxysmal atrial fibrillation (AF) compared with PVAC multi-electrode phased RF ablation, with beat-to-beat device-derived Holter monitoring throughout the study duration. Methods and results: An investigator-initiated prospective trial of patients with paroxysmal AF randomized (1:1:1) to initial surgical, nMARQ or PVAC ablation. All patients had continuous beat-to-beat monitoring with an ILR or pacemaker to evaluate and document AF recurrence. There was a strong trend (P = 0.050) toward difference in AF outcome, with surgical AF ablation more efficacious than catheter ablation. At one year, the proportion of patients with less than 1% AF burden after one procedure and off all antiarrhythmic drugs was 63, 56, and 90% for PVAC, nMARQ and surgical ablations respectively. There were significantly more repeat ablations in the catheter ablation groups (P = 0.008): 25% PVAC, 27% nMARQ, 0% surgery. However, 7 of 20 (35%) of patients undergoing surgical ablation suffered a procedural complication, including two sternotomies for bleeding and one death. This was higher than for catheter ablation (P < 0.001). Surgical ablation took longer to perform (P < 0.001) and had a longer hospital admission (P < 0.001) than catheter ablation. Conclusion: Surgical AF ablation required significantly fewer repeat procedures than catheter ablation, and there was a clear trend towards improved arrhythmia outcome. However, it was associated with a significantly higher rate of procedural complications. Surgical ablation for paroxysmal AF is promising, however more prospective outcome data is required. Clinical Trial Registration: NCT01504451, http://clinicaltrials.gov/show/NCT01504451.

Central arteriovenous anastomosis for the treatment of patients with uncontrolled hypertension (the ROX CONTROL HTN study): a randomised controlled trial.

BACKGROUND: Hypertension contributes to cardiovascular morbidity and mortality. We assessed the safety and efficacy of a central iliac arteriovenous anastomosis to alter the mechanical arterial properties and reduce blood pressure in patients with uncontrolled hypertension. METHODS: We enrolled patients in this open-label, multicentre, prospective, randomised, controlled trial between October, 2012, and April, 2014. Eligible patients had baseline office systolic blood pressure of 140 mm Hg or higher and average daytime ambulatory blood pressure of 135 mm Hg or higher systolic and 85 mm Hg or higher diastolic despite antihypertensive treatment. Patients were randomly allocated in a 1:1 ratio to undergo implantation of an arteriovenous coupler device plus current pharmaceutical treatment or to maintain current treatment alone (control). The primary endpoint was mean change from baseline in office and 24 h ambulatory systolic blood pressure at 6 months. Analysis was by modified intention to treat (all patients remaining in follow-up at 6 months). This trial is registered with ClinicalTrials.gov, number NCT01642498. FINDINGS: 83 (43%) of 195 patients screened were assigned arteriovenous coupler therapy (n=44) or normal care (n=39). Mean office systolic blood pressure reduced by 26·9 (SD 23·9) mm Hg in the arteriovenous coupler group (p<0·0001) and by 3·7 (21·2) mm Hg in the control group (p=0·31). Mean systolic 24 h ambulatory blood pressure reduced by 13·5 (18·8) mm Hg (p<0·0001) in arteriovenous coupler recipients and by 0·5 (15·8) mm Hg (p=0·86) in controls. Implantation of the arteriovenous coupler was associated with late ipsilateral venous stenosis in 12 (29%) of 42 patients and was treatable with venoplasty or stenting. INTERPRETATION: Arteriovenous anastomosis was associated with significantly reduced blood pressure and hypertensive complications. This approach might be a useful adjunctive therapy for patients with uncontrolled hypertension. FUNDING: ROX Medical.

The benefit of a remotely monitored implantable loop recorder as a first line investigation in unexplained syncope: the EaSyAS II trial.

AIMS: This prospective randomized controlled study evaluated the first-line use of a novel remotely monitored implantable loop recorder (ILR) in the initial investigation of unexplained syncope, and compared this to conventional therapy and a dedicated Syncope Clinic (SC). METHODS AND RESULTS: A total of 246 patients (mean age 70.3 years) were randomly allocated to conventional management, SC alone, ILR alone, or SC + ILR. Median follow-up was 20 months (IQR 15-25 months). Time to electrocardiogram (ECG) diagnosis was significantly shorter with ILR alone vs. conventional [hazard ratio (HR) 35.5, P = 0.0004] and with SC vs. conventional (HR 25.6, P = 0.002). Seventy-four per cent of first syncopal events documented in the SC groups occurred during provocative tilt testing. Twenty-two per cent of patients who received an ILR were found to have a bradycardia indication for permanent pacing, compared with 3% of patients who did not. Overall, more investigative tests were undertaken in the conventional group than in any other. Only patients who received an ILR had a significant increase in time to second syncope (P = 0.02), suggesting successful diagnosis and management of treatable causes of syncope. CONCLUSIONS: Implantable loop recorder monitoring achieved a more rapid diagnosis in unexplained syncope than usual care. Conventional management of syncope failed to achieve an ECG diagnosis despite a large number of investigative tests. Syncope Clinic and provocative tilt testing delivered a rapid ECG diagnosis, but did not prevent recurrent syncope. Implantable loop recorders offered rapid diagnosis, increased the likelihood of syncope being reported, demonstrated a high rate of intermittent bradycardia requiring pacing, and reduced recurrent syncope.

First clinical trial of specific IKACh blocker shows no reduction in atrial fibrillation burden in patients with paroxysmal atrial fibrillation: pacemaker assessment of BMS 914392 in patients with paroxysmal atrial fibrillation.

AIMS: To assess the efficacy of BMS 914392 on atrial fibrillation (AF) burden reduction in 20 patients with pacemakers and paroxysmal atrial fibrillation (PAF). BMS 914392 is a potent, selective, oral inhibitor of the IKACh current and has been shown to suppress AF, whilst having no effect on the ventricular refractory period. This is the first efficacy study of BMS 914392 in patients with PAF. METHODS AND RESULTS: The study was a four-way, crossover, double-blind design. A total of 20 patients with PAF and dual-chamber pacemakers were recruited. The pacemakers allowed beat-to-beat monitoring. Anti-arrhythmic drugs were withdrawn. Patients received low-dose (10 mg OD), medium-dose (10 mg TDS), and high-dose (20 mg TDS) BMS 914392 or placebo for 3 weeks before being crossed to the next phase. Patients underwent a washout period, four treatment phases and a final washout phase. Atrial fibrillation burden was downloaded from their pacemakers at the end of each study phase. BMS 914392 did not reduce AF burden when compared with placebo (10 mg OD P = 0.56, 10 mg TDS P = 0.22, 20 mg TDS P = 0.23). Heart rate and corrected QT (QTc) were not affected by BMS 914392. Adverse event (AE) rates did not differ from placebo in any of the treatment groups, with no serious AEs recorded. CONCLUSION: BMS 914932 has not been shown to reduce AF burden in patients with PAF and pacemakers using beat-to-beat pacemaker monitoring throughout the study. BMS 914392 was well tolerated and did not affect QTc or reduce heart rate. TRIAL REGISTRATION: Clinicaltrials.gov: NCT01356914.

Are implantable cardiac monitors the 'gold standard' for atrial fibrillation detection? A prospective randomized trial comparing atrial fibrillation monitoring using implantable cardiac monitors and DDDRP permanent pacemakers in post atrial fibrillation ablation patients.

AIMS: Implantable devices are widely accepted, but not proven, to be the most reliable monitoring method to assess atrial fibrillation (AF) therapies. We compared REVEAL(®)XT implantable cardiac monitors (ICMs) and permanent pacemakers (PPMs). METHODS AND RESULTS: Fifty patients with paroxysmal AF were randomized to ICM or PPM implant 6 weeks prior to pulmonary vein isolation. Permanent pacemakers were programmed to monitoring only (ODO). Device downloads were performed at 0, 3, 6, 9, and 12 months. All patients underwent 7-day external loop recorder. Device ECGs and EGMs were compared for AF burden. A total of 20 744 and 11 238 arrhythmia episodes were identified in the ICM and PPM groups, respectively. Correct identification of AF was significantly better in the PPM group (97 vs. 55% P < 0.001). In the ICM group, 26% of ECGs were un-interpretable. Sensitivity and specificity for each episode of AF was significantly better in the PPM group (100 vs. 79% and 98 vs. 66%, respectively, P < 0.001). The positive predictive value for the detection of any AF was significantly better in the PPM than the ICM (100 vs. 58%, P = 0.03). The negative predictive value for the absence of all AF was not significantly different between the PPM and ICM (100% vs. 92%, P = 0.76). CONCLUSION: Permanent pacemakers Holters are the most accurate method of evaluating arrhythmia burden and the therapeutic efficacy of novel AF therapies. ICM has a high degree of artefact, which reduces its specifity and sensitivity. Despite the deficiencies of ICM monitoring the negative predictive value of the ICM is satisfactory if zero AF burden is the aim of therapy.

The development of AF over time in patients with permanent pacemakers: objective assessment with pacemaker diagnostics demonstrates distinct patterns of AF.

AIMS: To describe the long-term patterns of atrial fibrillation (AF) in patients with permanent pacemakers. METHODS AND RESULTS: A total of 2092 pacemaker Holter downloads were analysed in 323 patients with dual chamber permanent pacemakers, describing a cumulative 1031 patient-years of beat-to-beat monitoring. Four subtypes of AF were applied: (i) non-progressive low-burden PAF (NPLB-PAF, n = 120): such patients never have >1% AF burden throughout follow-up; (ii) chronic progressive PAF (CP-PAF, n = 55): AF burden increases but is never 100%; (iii) relapsing-remitting PAF (RR-PAF, n = 78): AF burden has reduced at least once by more than 2% and is never 100%; (iv) persistent AF (PersAF, n = 70): 100% AF burden for at least 28 days. Overall, mean AF burden rose 0.34% per year (P < 0.0001). After accounting for age, heart failure (HF) had a significant interaction with AF burden (P = 0.0022), but HATCH score and CVA/TIA did not. There were no differences in the frequency or duration of monitoring between the four AF subtypes. Atrial fibrillation episode frequency discriminated between subtypes (P = 0.0004). Eighteen of 70 (26%) patients with PersAF had pacemaker documented episodes of sinus rhythm (i.e. reversion to 'paroxysmal AF') after the onset of PersAF. CONCLUSION: In this cohort, the development of AF over time appears more complex than current definitions suggest. Atrial fibrillation can remain low burden without progression, remit-relapse, or progress as is described in currently accepted definitions. More frequent episodes of AF indicated a favourable subtype. Persistent AF is not inevitable, and can revert to paroxysmal AF. CLINICAL TRIAL REGISTRATION: NCT02016950, http://clinicaltrials.gov/show/NCT02016950.

Tissue doppler-derived contractile reserve is a simple and strong predictor of cardiopulmonary exercise performance across a range of cardiac diseases.

BACKGROUND: Resting echocardiographic measures of cardiac function such as left ventricular ejection fraction correlate poorly with exercise capacity. Assessment during exercise using measures less dependent on hemodynamic loading conditions, such as tissue Doppler imaging (TDI), may more accurately characterize the relationship between cardiac function and exercise capacity. METHODS AND RESULTS: One hundred one subjects with various cardiac diagnoses underwent exercise stress echocardiography with simultaneous cardiopulmonary gas exchange analysis. Standard two-dimensional, Doppler and spectral TDI parameters were assessed at both rest and peak exercise. Across all subjects the strongest relationship with peak oxygen uptake (pVO2 ) was with peak left ventricular systolic tissue velocity (S') during exercise (r = 0.84, P < 0.001). The strength of the relationship was greater than that observed with any other common echocardiographic measure of systolic or diastolic cardiac function. CONCLUSION: There is a very strong relationship between measurements of S' during exercise and exercise capacity. The previously observed poor correlation with standard measures of systolic and diastolic cardiac function may be explained both by the load dependence of parameters such as ejection fraction and by reliance on resting as opposed to exercise assessment.

A randomized comparison of retrograde left-sided versus anterograde right-sided ablation of the atrioventricular junction.

BACKGROUND: Catheter ablation of the atrioventricular node (AVN) is an effective treatment for patients with symptomatic atrial fibrillation. This study compares the success rate, procedure time, radiation time, and complication rates of retrograde left-sided (LSA) and anterograde right-sided (RSA) AVN ablation in a randomised controlled trial. METHODS: Thirty-one patients undergoing AVN ablation were randomized to either LSA (15 patients) or RSA (16 patients). Crossover occurred after six unsuccessful radiofrequency (RF) applications. RESULTS: The LSA cohort had a mean age of 77.00 ± 5.17 and the RSA cohort was 79.44 ± 6.08 (p = .0240). There were five crossovers from LSA to RSA and there was one crossover from RSA to LSA. There was no significant difference in ablation time between LSA and RSA (210.40 ± 179.77 vs. 192.19 ± 130.29 seconds, p = .748). There was no significant difference in procedure time, fluoroscopy time, radiation dose, or number of RF applications between the two groups. There was 1 (6.67%) serious adverse event in the LSA group and 1 (6.25%) in the RSA group due to femoral hematomas requiring blood transfusion or intervention. There was no significant difference in patient-reported discomfort between LSA and RSA (16.43 ± 20.67 vs. 17.87 ± 28.08, p = .877). The study was stopped before full recruitment due to futility. CONCLUSIONS: Retrograde LSA of the AVN does not reduce RF applications, procedure time, or radiation exposure compared with conventional RSA and cannot be recommended as a first-line clinical approach.

A randomized sham-controlled study of pulmonary vein isolation in symptomatic atrial fibrillation (The SHAM-PVI study): Study design and rationale.

INTRODUCTION: Pulmonary vein (PV) isolation has been shown to reduce atrial fibrillation (AF) burden and symptoms in patients. However, to date previous studies have been unblinded raising the possibility of a placebo effect to account for differences in outcomes. HYPOTHESIS & METHODS: The objective of this study is to compare PV isolation to a sham procedure in patients with symptomatic AF. The SHAM-PVI study is a double blind randomized controlled clinical trial. 140 patients with symptomatic paroxysmal or persistent AF will be randomized to either PV isolation (with cryoballoon ablation) or a sham procedure (with phrenic nerve pacing). All patients will receive an implantable loop recorder. The primary outcome is total AF burden at 6 months postrandomisation (excluding the 3 month blanking period). Key secondary outcomes include (1) time to symptomatic and asymptomatic atrial tachyarrhythmia (2) total atrial tachyarrhythmia episodes and (3) patient reported outcome measures. RESULTS: Enrollment was initiated in January 2020. Through April 2023 119 patients have been recruited. Results are expected to be disseminated in 2024. CONCLUSION: This study compares PV isolation using cryoablation to a sham procedure. The study will estimate the effect of PV isolation on AF burden.

The effect of second-generation cryoablation without electrical mapping in persistent AF using continuous monitoring.

BACKGROUND: Second-generation cryoballoon ablation is safe and effective in patients with persistent atrial fibrillation (AF). The aim of this study is to report the real long-term AF burden and freedom from AF post-cryoablation using continuous monitoring, and to assess whether intraoperative confirmation of pulmonary vein isolation using electrical mapping is necessary. METHODS: A total of 33 patients (mean age 75.7 ± 5.6 years, 16 men) with persistent AF who underwent second-generation cryoablation without electrical mapping were reviewed. All patients had a cardiac implantable device and were followed up for a mean of 755 ± 170 days. RESULTS: AF burden significantly decreased from 67.51% ± 34.90% to 18.28% ± 26.65% at 1-year follow-up, and this reduction was maintained at final follow-up (18.26% ± 23.70%, p < 0.001). Continuous monitoring revealed a freedom from AF rate of 33% and 24% at 1-year and full follow-up, respectively. Patients who remained in persistent AF at final follow-up had a trend towards higher pre-ablation AF burden (81.6% ± 29.7% vs 57.3% ± 36.4%, p = 0.08). CONCLUSION: Second-generation cryoablation without confirming pulmonary vein isolation using electrical mapping is effective leading to significant reductions in AF burden based on continuous beat-to-beat monitoring at 1-year and long-term follow-up.

All is not lost: utilizing continuous remote ILR monitoring to diagnose syncope.

A 63-year-old man with frequent unexplained syncope was implanted with a second generation remotely monitored implantable loop recorder for continuous electrocardiogram (ECG) monitoring. He had a subsequent syncopal episode and despite accidental destruction of his patient activator, vital ECG data from the event were transmitted wirelessly, enabling a cardiac arrhythmia to be excluded. This case highlights the benefit of remote monitoring in syncope assessment, as well as a transmission system that ensures prompt analysis of the ECG data and therefore rapid optimal patient management.

The effect of bipole tip-to-ring distance in atrial electrodes upon atrial tachyarrhythmia sensing capability in modern dual-chamber pacemakers.

INTRODUCTION: Accurate atrial arrhythmia discrimination is important for dual chamber pacemakers and defibrillators. The aim was to assess the accuracy of atrial arrhythmia recording using modern devices and relate this to atrial tip-to-ring (TTR) distance. METHODS: One hundred eighty-two patients (72 + or - 9 years, 55% male) with paroxysmal atrial fibrillation were enrolled and were included in the study if they had an atrial fibrillation (AF) burden of 1-50% during a monitoring phase. Seventy-nine patients fulfilled these criteria and were followed for at least 5 months. Electrodes were classified as having short (<10 mm), medium (10-12), or long (13-18) atrial TTR spacing. RESULTS: Two thousand eight hundred eighty-three detailed onset reports were analyzed; 730 (25%) demonstrated aberrant sensing. Six percent were due to farfield R wave oversensing (FFRWO) and 19% due to undersensing, sometimes occurring in the same patient and study phase. FFRWO was significantly reduced with short TTR electrodes (P < 0.05). Undersensing due to sensitivity fallout was 18% (short), 24% (medium), and 17% (long) (P = ns). Undersensing due to pacemaker blanking was 11% (short), 11% (medium), and 12% (long) (P = ns). Active fixation electrodes did not show any difference from passive fixation. CONCLUSION: Atrial electrodes with a short TTR (<10 mm) significantly reduce FFRWO without increasing undersensing and should be used routinely in patients with paroxysmal atrial tachyarrhythmias. However, 20% of atrial tachyarrythmia episodes were incorrectly classified as terminated by these modern devices due to undersensing. Clinicians should be wary of using device-derived endpoints that rely on AF episode number or duration as these may be falsely increased or reduced, respectively.