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.

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.

Improved Therapeutic Approaches are Needed to Manage Graft-versus-Host Disease.

Allogeneic haematopoietic stem cell transplantation (alloHSCT) offers a potentially curative therapy for patients suffering from diseases of the haematopoietic system but requires a high level of expertise and is both resource intensive and expensive. A frequent and life-threatening complication is graft-versus-host disease (GvHD). Acute GvHD (aGvHD) generally causes skin, gastrointestinal and liver symptoms, but chronic GvHD (cGvHD) has a different pathophysiology and may affect nearly every organ or tissue of the body. In Europe, GvHD prophylaxis is generally a calcineurin inhibitor in combination with methotrexate, with high-dose systemic steroids used for advanced GvHD treatment. Between 39% and 59% of alloHSCT patients will develop aGvHD and around 36-37% will develop cGvHD. Steroid response decreases with increasing disease severity, which in turn leads to an increase in non-relapse mortality. GvHD imposes a financial burden on healthcare systems, significantly increasing post-alloHSCT costs. Increased GvHD disease severity magnifies this. Balancing immunosuppression to control the GvHD whilst maintaining a degree of immunocompetence against infection is critical. European GvHD guidelines acknowledge the lack of evidence to support a standard second-line therapy, and improved long-term outcomes and quality-of-life (QoL) remain an unmet need. Evidence generation for potential treatments is challenging. Issues to overcome include choice of comparator (extensive off-label usage); blinding; selection of relevant patient-reported outcome measures (PROMs); and rarity of the condition, which may infeasibly increase timescales to achieve clinical and statistical relevance.

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.

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.

Acute coronary syndrome caused by extrinsic coronary compression from an aortic root abscess in a patient with mechanical aortic valve endocarditis: a case report and literature review.

BACKGROUND: Extrinsic coronary compression is an extremely rare complication of aortic root abscess formation and can manifest as an acute coronary syndrome in infective endocarditis. Optimal management strategies are unknown and therefore illustrative case reports may be informative. CASE SUMMARY: We describe a 63-year-old man with a background history of a mechanical aortic valve who developed sepsis due to Escherichia coli bacteraemia from a presumed urinary source. He suddenly deteriorated with cardiogenic shock and anterior ST-segment elevation myocardial infarction on Day 16 and received emergency percutaneous coronary intervention for severe stenoses of left anterior descending and diagonal arteries. A transoesophageal echocardiogram 2 days later demonstrated a large aortic root abscess. He was transferred for emergency surgery which revealed a large aortic abscess surrounding the left main stem confirming extrinsic coronary compression. He received a redo tissue aortic valve replacement and repair of his abscess cavity. DISCUSSION: We describe a case where percutaneous coronary intervention and emergency surgery was used to treat extrinsic compression from an aortic root abscess; a complication that is associated with a high mortality. This is also a rare case of E. coli causing prosthetic valve endocarditis. We also explore the findings of 11 previous cases of extrinsic coronary compression from aortic root abscess.

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.

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.

Utilising video technology in the cardiac catheter lab and operating theatre during the COVID-19 pandemic.

The COVID-19 pandemic has significantly altered working practices within hospitals. This includes surgical theatres and cardiac catheter laboratories. Here we describe how we have harnessed the use of video technology to improve the running of the cardiac catheter lab in our institution, reducing the exposure of staff members to COVID-19, reducing the need for personal protective equipment (PPE) and maintaining and enhancing educational and teaching opportunities for trainees.

An economic evaluation of an advanced video conferencing system for cardiac multidisciplinary team meetings.

INTRODUCTION: Current UK and international guidelines advocate the need for multidisciplinary team (MDT) discussion of selected patients undergoing either percutaneous or surgical cardiac procedures to decide the optimal treatment strategy. To date, it is unknown if using videoconference facilities is cost-effective. Therefore, we performed a cost analysis of using a high-speed internet video conferencing system compared with conventional face-to-face MDT meetings. METHODS: Costs of running a conventional MDT meeting vs a video conferencing MDT were modelled and compared over a 2-year period. Participants were also surveyed on the overall effectiveness of conducting remote MDTs. RESULTS: The set-up and maintenance cost of the video conferencing system over 2 years was £30 400. The staff costs of running the face-to-face MDT were £95 970 and the video conferencing MDT was £23 992.50. The total travel costs of the conventional face-to-face MDTs were £10 555.34. In total, the cost of the conventional face-to-face MDT was £106 525.34 and the video conferencing MDT was £54 392.50 representing a cost saving of 48.9%. Participants rated the effectiveness of conducing a remote MDT and the ease of technology use as very good. CONCLUSIONS: Video conferencing systems provide a highly cost-effective method of facilitating MDT meetings between cardiologists and cardiac surgeons at remote centres.

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.

The hemodynamic effects of a central iliac arteriovenous anastomosis at 6 months in patients with resistant and uncontrolled hypertension.

A central iliac arteriovenous anastomosis, termed the "coupler" (ROX Medical), results in a significant reduction in blood pressure (BP) in hypertensive patients. This study assessed functional and hemodynamic changes induced by the device. Twenty-one patients with resistant and/or uncontrolled hypertension underwent stress echocardiography and cardiopulmonary exercise testing (CPET) at baseline and 6 months post-coupler implantation. End points were selected to best evaluate cardiac function including Doppler stroke volume (SV), septal and lateral E/E', and right ventricular systolic velocity S' (RV S'). CPET VO2 peak demonstrated total cardiopulmonary performance. SV increased from 76.4 SD12.2 mL to 92.1 SD22.7 mL 6 months post-coupler insertion; P = .002. No changes in RV S', septal or lateral E/E', or VO2 peak were observed. Five patients experienced increased diuretic requirement ≥3 times baseline. RV S' fell from 19.0 SD1.87 cm/s to 16.80 SD3.43 cm/s in these patients (P > .05). A significant increase in SV 6 months post-coupler insertion was observed. In patients with increased diuretic requirement, the device was associated with a lower RV S' suggesting occult RV dysfunction as the mechanism of this pre-specified adverse outcome.

Central Iliac Arteriovenous Anastomosis for Uncontrolled Hypertension: One-Year Results From the ROX CONTROL HTN Trial.

Creation of a central iliac arteriovenous anastomosis using a novel nitinol coupler device results in an immediate, significant reduction of blood pressure (BP). We present efficacy and safety findings at 12 months post-coupler insertion. This open-label, multicenter, prospective, randomized trial enrolled patients with a baseline office systolic BP ≥140 mm Hg and average daytime ambulatory BP ≥135/85 mm Hg. Subjects were randomly allocated to coupler implantation and continuing previous pharmacotherapy or to maintain previous treatment alone. At 12 months, 39 patients who had coupler therapy were included in the intention-to-treat analysis. Office-based systolic BP reduced by 25.1±23.3 mm Hg (baseline, 174±18 mm Hg; P<0.0001) post-coupler placement, and office diastolic BP reduced by 20.8±13.3 mm Hg (baseline, 100±13 mm Hg; P<0.0001). Mean 24-hour ambulatory BP reduced by 12.6±17.4/15.3±9.7 mm Hg (P<0.0001 for both). In a prespecified subset of patients who failed to respond adequately to prior renal denervation, coupler therapy led to highly significant reduction in office systolic/diastolic BP (30.7/24.1 mm Hg) and significant reduction in 24-hour ambulatory systolic/diastolic BP (12.4/14.4 mm Hg) at 12 months (n=9). After coupler therapy, 14 patients (33%) developed ipsilateral venous stenosis; all were treated successfully with venous stenting. These findings confirm the importance of arterial mechanics in the pathophysiology of hypertension and support the clinical use of a central iliac arteriovenous anastomosis. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01642498.

Clinical events and echocardiographic lesion progression rate in subjects with mild or moderate aortic regurgitation.

Background: The rate of progression of aortic regurgitation (AR) is not well described. Current guidelines state that asymptomatic patients with mild AR should be followed up every 3­5 years and 1­2 yearly for moderate AR. This study describes the lesion and clinical based progression of mild and moderate AR in a population of patients undergoing systematic follow-up. Methods and results: 341 patients with either mild or moderate AR were included. The rates of clinical events (death, aortic valve replacement and cardiac hospitalization) and progression of AR are reported. 341 patients were included; mean age was 71.1 years (IQR 66­80 years) and the median follow-up period was 4.6 (IQR 2­6.7) years. 292 patients did not have any events during follow-up. 3 patients required aortic valve replacement (2 of these due to severe aortic stenosis and 1 due to severe mitral regurgitation and co-existent moderate AR). 44 patients required cardiac hospitalization. 9 patients died during follow-up and 35 patients (10%) showed a progression of AR during follow-up with an average time of 4.0 ± 2.6 years. 8 patients (2.3% of the total) progressed to severe AR. Patients with mixed valvular pathology showed a greater increase in AR progression (27 (15%) vs 8 (5%); P = 0.004). Conclusions: Over medium term systematic follow-up progression and clinical events in patients with AR is rare, regardless of etiology. Patients who suffered from AR as an isolated valve pathology were less likely to show AR progression over time.

Effect of Arteriovenous Anastomosis on Blood Pressure Reduction in Patients With Isolated Systolic Hypertension Compared With Combined Hypertension.

BACKGROUND: Options for interventional therapy to lower blood pressure (BP) in patients with treatment-resistant hypertension include renal denervation and the creation of an arteriovenous anastomosis using the ROX coupler. It has been shown that BP response after renal denervation is greater in patients with combined hypertension (CH) than in patients with isolated systolic hypertension (ISH). We analyzed the effect of ROX coupler implantation in patients with CH as compared with ISH. METHODS AND RESULTS: The randomized, controlled, prospective ROX Control Hypertension Study included patients with true treatment-resistant hypertension (office systolic BP ≥140 mm Hg, average daytime ambulatory BP ≥135/85 mm Hg, and treatment with ≥3 antihypertensive drugs including a diuretic). In a post hoc analysis, we stratified patients with CH (n=31) and ISH (n=11). Baseline office systolic BP (177±18 mm Hg versus 169±17 mm Hg, P=0.163) and 24-hour ambulatory systolic BP (159±16 mm Hg versus 154±11 mm Hg, P=0.463) did not differ between patients with CH and those with ISH. ROX coupler implementation resulted in a significant reduction in office systolic BP (CH: -29±21 mm Hg versus ISH: -22±31 mm Hg, P=0.445) and 24-hour ambulatory systolic BP (CH: -14±20 mm Hg versus ISH: -13±15 mm Hg, P=0.672), without significant differences between the two groups. The responder rate (office systolic BP reduction ≥10 mm Hg) after 6 months was not different (CH: 81% versus ISH: 82%, P=0.932). CONCLUSIONS: Our data suggest that creation of an arteriovenous anastomosis using the ROX coupler system leads to a similar reduction of office and 24-hour ambulatory systolic BP in patients with combined and isolated systolic hypertension. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01642498.

Structural cure for reflex syncope?

The ROX Coupler is a device that allows creation of a central arteriovenous anastomosis at the iliac level. The device has been shown to improve exercise capacity in patients with chronic obstructive pulmonary disease and is CE marked for the treatment of resistant and uncontrolled hypertension. Reflex syncope is a challenging clinical condition with limited proven therapeutic options. We describe the resolution of symptoms and tilt table response of a patient who underwent insertion of a ROX Coupler to treat hypertension, and also incidentally had pre-existing vasodepressor 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.