Validation of a prediction model for early reconnection after cryoballoon ablation

BACKGROUND

We previously developed an early reconnection/dormant conduction (ERC) prediction model for cryoballoon ablation to avoid a 30-min waiting period with adenosine infusion. We now aimed to validate this model based on time to isolation, number of unsuccessful cryo-applications, and nadir balloon temperature.

METHODS

Consecutive atrial fibrillation patients who underwent their first cryoballoon ablation in 2018-2019 at the Leiden University Medical Center were included. Model performance at the previous and at a new optimal cutoff value was determined.

RESULTS

A total of 201 patients were included (85.57% paroxysmal AF, 139 male, median age 61 years (IQR 53-69)). ERC was found in 35 of 201 included patients (17.41%) and in 41 of 774 veins (5.30%). In the present study population, the previous cutoff value of - 6.7 provided a sensitivity of 37.84% (previously 70%) and a specificity of 89.07% (previously 86%). Shifting the cutoff value to - 7.2 in both study populations resulted in a sensitivity of 72.50% and 72.97% and a specificity of 78.22% and 78.63% in data from the previous and present study respectively. Negative predictive values were 96.55% and 98.11%. Applying the model on the 101 patients of the present study with all necessary data for all veins resulted in 43 out of 101 patients (43%) not requiring a 30-min waiting period with adenosine testing. Two patients (2%) with ERC would have been missed when applying the model.

CONCLUSIONS

The previously established ERC prediction model performs well, recommending its use for centers routinely using adenosine testing following PVI.

Improved prehospital triage for acute cardiac care: results from HART-c, a multicentre prospective study

BACKGROUND

Cardiac symptoms are one of the most prevalent reasons for emergency department visits. However, over 80% of patients with such symptoms are sent home after acute cardiovascular disease has been ruled out.

OBJECTIVE

The Hollands-Midden Acute Regional Triage-cardiology (HART-c) study aimed to investigate whether a novel prehospital triage method, combining prehospital and hospital data with expert consultation, could increase the number of patients who could safely stay at home after emergency medical service (EMS) consultation.

METHODS

The triage method combined prehospital EMS data, such as electrocardiographic and vital parameters in real time, and data from regional hospitals (including previous medical records and admission capacity) with expert consultation. During the 6‑month intervention and control periods 1536 and 1376 patients, respectively, were consulted by the EMS. The primary endpoint was the percentage change of patients who could stay at home after EMS consultation.

RESULTS

The novel triage method led to a significant increase in patients who could safely stay at home, 11.8% in the intervention group versus 5.9% in the control group: odds ratio 2.31 (95% confidence interval (CI) 1.74-3.05). Of 181 patients staying at home, only 1 (< 1%) was later diagnosed with ACS; no patients died. Furthermore the number of interhospital transfers decreased: relative risk 0.81 (95% CI 0.67-0.97).

CONCLUSION

The HART‑c triage method led to a significant decrease in interhospital transfers and an increase in patients with cardiac symptoms who could safely stay at home. The presented method thereby reduced overcrowding and, if implemented throughout the country and for other medical specialties, could potentially reduce the number of cardiac and non-cardiac hospital visits even further.

Predicting early reconnection after cryoballoon ablation with procedural and biophysical parameters

BACKGROUND

Predicting early reconnection/dormant conduction (ERC) immediately after pulmonary vein isolation (PVI) can avoid a waiting period with adenosine testing.

OBJECTIVE

To identify procedural and biophysical parameters predicting ERC.

METHODS

Consecutive atrial fibrillation (AF) patients undergoing a first cryoballoon ablation (Arctic Front Advance) between 2014 and 2017 were included. ERC was defined as manifest or dormant pulmonary vein (PV) reconnection with adenosine 30 minutes after PVI. Time to isolation (TTI), balloon temperatures (BT), and thawing times were evaluated as potential predictors for ERC. Based on a multivariable model, cut-off-values were defined and a formula was constructed to be used in clinical practice.

RESULTS

A total of 136 patients (60 ± 10 years, 96 male, 95% paroxysmal AF) were included. ERC was found in 40 (29%) patients (ERC group) and in 53 of 575 (9%) veins. Procedural and total ablation time and the number of unsuccessful freezes were significantly longer/higher in the ERC group compared to the non-ERC group (150 ± 40 vs 125 ± 34 minutes; 24 ± 5 vs 17 ± 4 minutes, and 38% vs 24%, respectively (P = .028). Multivariable analysis showed that a higher nadir balloon temperature (hazard ratio [HR] 1.17 [1.09-1.23, P < .001), a higher number of unsuccessful freezes (HR 1.69 [1.15-2.49], P = .008) and a longer TTI (HR 1.02 [1.01-1.03], P < .001) were independently associated with ERC, leading to the following formula: 0.02 × TTI + 0.5 × number of unsuccessful freezes + 0.2 × nadir BT with a cut-off value of ≤-6.7 to refrain from a waiting period with adenosine testing.

CONCLUSION

Three easily available parameters were associated with ERC. Using these parameters during ablation can help to avoid a 30-minute waiting period and adenosine testing.

Prehospital triage of patients with acute cardiac complaints: study protocol of HART-c, a multicentre prospective study

INTRODUCTION

Emergency department (ED) overcrowding is a major healthcare problem associated with worse patient outcomes and increased costs. Attempts to reduce ED overcrowding of patients with cardiac complaints have so far focused on in-hospital triage and rapid risk stratification of patients with chest pain at the ED. The Hollands-Midden Acute Regional Triage-Cardiology (HART-c) study aimed to assess the amount of patients left at home in usual ambulance care as compared with the new prehospital triage method. This method combines paramedic assessment and expert cardiologist consultation using live monitoring, hospital data and real-time admission capacity.

METHODS AND ANALYSIS

Patients visited by the emergency medical services (EMS) for cardiac complaints are included. EMS consultation consists of medical history, physical examination and vital signs, and ECG measurements. All data are transferred to a newly developed platform for the triage cardiologist. Prehospital data, in-hospital medical records and real-time admission capacity are evaluated. Then a shared decision is made whether admission is necessary and, if so, which hospital is most appropriate. To evaluate safety, all patients left at home and their general practitioners (GPs) are contacted for 30-day adverse events.

ETHICS AND DISSEMINATION

The study is approved by the LUMC's Medical Ethics Committee. Patients are asked for consent for contacting their GPs. The main results of this trial will be disseminated in one paper.

DISCUSSION

The HART-c study evaluates the efficacy and feasibility of a prehospital triage method that combines prehospital patient assessment and direct consultation of a cardiologist who has access to live-monitored data, hospital data and real-time hospital admission capacity. We expect this triage method to substantially reduce unnecessary ED visits.

An initial exploration of subtraction electrocardiography to detect myocardial ischemia in the prehospital setting

Background

Methods

Results

Conclusions

Optimizing ablation duration using dormant conduction to reveal incomplete isolation with the second generation cryoballoon: A randomized controlled trial

Introduction

Efficacy of cryoballoon ablation depends on balloon‐tissue contact and ablation duration. Prolonged duration may increase extracardiac complications. The aim of this study is to determine the optimal additional ablation duration after acute pulmonary vein isolation (PVI).

Methods

Consecutive patients with paroxysmal AF were randomized to three groups according to additional ablation duration (90, 120, or 150 seconds) after acute PVI (time‐to‐isolation). Primary outcome was reconnection/dormant conduction (DC) after a 30 minutes waiting period. If present, additional 240 seconds ablations were performed. Ablations without time‐to‐isolation <90 seconds, esophageal temperature <18°C or decreased phrenic nerve capture were aborted. Patients were followed with 24‐hour Holter monitoring at 3, 6, and 12 months.

Results

Seventy‐five study patients (60 ± 11 years, 48 male) were included. Reconnection/DC per vein significantly decreased (22%, 6% and 4%) while aborted ablations remained stable (respectively 4, 5, and 7%) among the 90, 120, and 150 seconds groups. A shorter cryo‐application time, longer time‐to‐isolation, higher balloon temperature and unsuccessful ablations predicted reconnection/DC. Freedom of atrial fibrillation was, respectively, 52, 56, and 72% in 90, 120, and 150 seconds groups ( P = 0.27), while repeated procedures significantly decreased from 36% to 4% ( P = 0.041) in the longer duration group compared to shorter duration group (150 seconds vs 90 seconds group). In multivariate Cox‐regression only reconnection/DC predicted recurrence.

Conclusion

Prolonging ablation duration after time‐to‐isolation significantly decreased reconnection/DC and repeated procedures, while recurrences and complications rates were similar. In a time‐to‐isolation approach, an additional ablation of 150 seconds ablation is the most appropriate.

Impact of left atrial box surface ratio on the recurrence after ablation for persistent atrial fibrillation

Background

The posterior wall of the left atrium (LA) is a well‐known substrate for atrial fibrillation (AF) maintenance. Isolation of the posterior wall between the pulmonary veins (box lesion) may improve ablation success. Box lesion surface area size varies depending on the individual anatomy. This retrospective study evaluates the influence of box lesion surface area as a ratio of total LA surface area (box surface ratio) on arrhythmia recurrence.

Methods

Seventy consecutive patients with persistent AF (63 ± 11 years, 53 men) undergoing computed tomography (CT) imaging and ablation procedure consisting of a first box lesion were included in this study. Box lesion surface area was measured on electroanatomical maps and total LA surface area was derived from CT. Patients were followed with 24‐h electrocardiography and exercise tests at 3, 6, and 12 months after AF ablation. Arrhythmia recurrence was defined as any AF/atrial tachycardia (AT) beyond 3 months without antiarrhythmic drugs.

Results

During a median follow‐up of 13 (interquartile range = 10‐17) months, 42 (60%) patients had AF/AT recurrence. Multivariate Cox proportional regression analysis showed that a larger box surface ratio protected against recurrence (hazard ratio [HR] = 0.81; 95% confidence interval [CI] = 0.690‐0.955; P = 0.012). Left atrial volume index (HR = 1.01 [0.990‐1.024, P = 0.427] and a history of mitral valve surgery (HR = 2.90; 95% CI = 0.970‐8.693; P = 0.057) were not associated with AF recurrence in multivariate analysis.

Conclusion

A larger box lesion surface area as a ratio of total LA surface area is protective for AF/AT recurrence after ablation for persistent AF.

Effect of Non-fluoroscopic Catheter Tracking on Radiation Exposure during Pulmonary Vein Isolation: Comparison of Four ablation systems

Background

A novel non-fluoroscopic catheter tracking system (Mediguide) can be used in combination with a 3D mapping system for atrial fibrillation (AF) ablation. However, the benefit on radiation exposure of the Mediguide system compared to other ablation systems is unknown.

Methods

We retrospectively enrolled consecutive 73 patients (51 men; 59±11 years; 60 paroxysmal AF) undergoing pulmonary vein isolation by the same operator. Radiation time, radiation effective dose, procedure time, AF recurrence after ablation, and procedure-related complications were compared among 4 different ablation systems.

Results

Mediguide was used in 16 patients (group A), CARTO™ in 17 (group B), Cryoballoon in 30 (group C), and Multi-electrode Pulmonary Vein Ablation Catheter (PVAC) in 10 (group D). Although procedure time was shorter in patients with Cryoballoon (median 110 [interquartile range 99-120] min) and PVAC (123 [112-146] min) compared to those with Mediguide (181 [168-214] min) and CARTO (179 [160-195] min) (P<0.001), radiation exposure time and effective dose were decreased in patients with Mediguide compared to the other ablation systems (A: 5 [3-6] min; B: 14 [11-16] min; C: 14 [11-18] min; D: 20 [16-24] min, P<0.001 and A: 1.1 [0.8-2.0] mSv; B: 2.5 [1.3-3.8] mSv; C: 2.0 [1.4-2.5] mSv; D: 1.7 [1.4-3.6] mSv, P=0.015, respectively). AF recurrence rates and procedure-related complications were comparable among the 4 groups.

Conclusion

The Mediguide system reduces radiation exposure compared to other ablation systems without increasing AF recurrence or procedure-related complications.

Mobile phones in cryptogenic strOke patients Bringing sIngle Lead ECGs for Atrial Fibrillation detection (MOBILE-AF): study protocol for a randomised controlled trial

Background

Recently published randomised clinical trials indicate that prolonged electrocardiom (ECG) monitoring might enhance the detection of paroxysmal atrial fibrillation (AF) in cryptogenic stroke or transient ischaemic attack (TIA) patients. A device that might be suitable for prolonged ECG monitoring is a smartphone-compatible ECG device (Kardia Mobile, Alivecor, San Francisco, CA, USA) that allows the patient to record a single-lead ECG without the presence of trained health care staff. The MOBILE-AF trial will investigate the effectiveness of the ECG device for AF detection in patients with cryptogenic stroke or TIA. In this paper, the rationale and design of the MOBILE-AF trial is presented.

Methods

For this international, multicentre trial, 200 patients with cryptogenic stroke or TIA will be randomised. One hundred patients will receive the ECG device and will be asked to record their ECG twice daily during a period of 1 year. One hundred patients will receive a 7-day Holter monitor.

Discussion

The primary outcome of this study is the percentage of patients in which AF is detected in the first year after the index ischaemic stroke or TIA. Secondary outcomes include markers for AF prediction, orally administered anticoagulation therapy changes, as well as the incidence of recurrent stroke and major bleeds. First results can be expected in mid-2019.

Trial registration

ClinicalTrials.gov, ID: NCT02507986. Registered on 15 July 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2131-0) contains supplementary material, which is available to authorized users.

Inflammation increases plasma angiopoietin-like protein 4 in patients with the metabolic syndrome and type 2 diabetes

BACKGROUND

Angiopoietin-like protein 4 (ANGPTL4) inhibits lipoprotein lipase and associates with dyslipidemia. The expression of ANGPTL4 is regulated by free fatty acids (FFA) that activate lipid-sensing peroxisome proliferator-activated receptors (PPARs), but FFA can also activate pattern recognition receptors including Toll-like receptor 4 (TLR4) in macrophages.

OBJECTIVE

To assess whether systemic low-grade inflammation is a determinant for plasma ANGPTL4 levels in patients with the metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM).

DESIGN

We studied 335 male participants: healthy controls (Controls), patients with the MetS without inflammation (MetS-I) and with low-grade inflammation (MetS+I), and patients with T2DM. All patients without diabetes included in the present study were initially matched for waist circumference. In plasma, ANGPTL4, C reactive protein (CRP) and metabolic parameters were determined. Underlying mechanisms were examined using human macrophages in vitro.

RESULTS

As compared with Controls, plasma ANGPTL4 levels were increased in patients with MetS-I, MetS+I, and T2DM. Furthermore, ANGPTL4 was increased in T2DM compared with MetS-I. In fact, plasma CRP correlated positively with plasma ANGPTL4. In vitro studies showed that TLR 3/4 activation largely increased the expression and release of ANGPTL4 by macrophages.

CONCLUSIONS

Plasma ANGPTL4 levels in humans are predicted by CRP, a marker of inflammation, and ANGPTL4 expression by macrophages is increased by inflammatory stimuli.

Plasma apolipoprotein CI and CIII levels are associated with increased plasma triglyceride levels and decreased fat mass in men with the metabolic syndrome

OBJECTIVE

To determine whether, in accordance with observations in mouse models, high concentrations of the lipoprotein lipase inhibitors apolipoprotein (Apo) CI and ApoCIII are associated with increased triglyceride concentrations and decreased fat mass in men with the metabolic syndrome.

RESEARCH DESIGN AND METHODS

Plasma ApoCI, ApoCIII, and triglyceride concentrations were measured in the postabsorptive state in 98 men with the metabolic syndrome. Subcutaneous and visceral fat areas were measured by 3T-magnetic resonance imaging.

RESULTS

Triglyceride concentrations were 49% higher, and the average visceral fat area was 26% lower (both P < 0.001), in subjects with high ApoCI and ApoCIII compared with low ApoCI and ApoCIII. Subjects with either high ApoCI or ApoCIII had 16% (P < 0.05) and 18% (P < 0.01) decreased visceral fat area, respectively.

CONCLUSIONS

High concentrations of ApoCI and ApoCIII are associated with increased triglycerides and decreased visceral fat mass in men with the metabolic syndrome. These findings translate mouse studies into human pathophysiology.

Assessment of aortic pulse wave velocity and cardiac diastolic function in subjects with and without the metabolic syndrome: HDL cholesterol is independently associated with cardiovascular function

OBJECTIVE

To evaluate the influence of lipid and glucose metabolism in the metabolic syndrome on aortic pulse wave velocity (PWV) and left ventricular (LV) diastolic function using magnetic resonance imaging (MRI).

RESEARCH DESIGN AND METHODS

Aortic PWV and LV diastolic function were assessed using MRI in 16 subjects with the metabolic syndrome and 16 subjects without the metabolic syndrome matched for age, waist circumference, and blood pressure. The groups were compared using the unpaired t test or Mann-Whitney U test, and linear regression analysis was applied.

RESULTS

Aortic PWV was increased and LV diastolic function was decreased in subjects with compared with those without the metabolic syndrome. HDL cholesterol was independently associated with aortic PWV (R = -0.470, P < 0.01) and LV diastolic function (R = -0.421, P = 0.02).

CONCLUSIONS

Increased aortic PWV and decreased LV diastolic function is observed in subjects with the metabolic syndrome, regardless of blood pressure. Moreover, HDL cholesterol is independently associated with aortic PWV and LV diastolic function.

The impact of metabolic syndrome and CRP on vascular phenotype in type 2 diabetes mellitus

BACKGROUND

The burden of cardiovascular disease in diabetes mellitus type 2 (DM2) patients is variable. We hypothesize that metabolic syndrome (MS) and low-grade systemic inflammation modify the extent of atherosclerosis in DM2.

METHODS

Vascular phenotype was determined using the following endothelium-related, hemostatic, and sonographic endpoints in 62 DM2 patients with mild dyslipidemia: sVCAM, sE-selectin, von Willebrand factor (VWF), fibrinogen, s-thrombomodulin (sTM), tPA, PAI-1, flow-mediated dilation (FMD), and intima media thickness (IMT). The impact of MS load (number of criteria present), MS components, and CRP on these parameters was assessed.

RESULTS

Serum sVCAM, sTM, and tPA levels significantly increased with increasing MS load. IMT also significantly increased from 0.602+/-0.034 (one MS criterion) to 0.843+/-0.145 (four MS criteria, p=0.007). LogCRP significantly correlated with fibrinogen, PAI-1, and IMT. In a multiple regression (MR) model with age and gender as covariates, MS load predicted sVCAM and sTM; CRP predicted PAI-1 and fibrinogen; MS load and CRP simultaneously predicted tPA and IMT. For each MS criterion present, IMT significantly increased by 0.04 mm. An increase in CRP from 1 to 3 mg/L resulted in a significant increase of 0.04 mm. Patients with four MS criteria and inflammation (CRP >or=3 mg/L) are predicted to have a 0.21 mm thicker IMT than those without. A second stepwise MR analysis based on gender, traditional risk factors, diabetes-related parameters, renal function, individual MS criteria, and LogCRP as explanatory variables showed a significant effect of systolic and diastolic blood pressure, HDL, and LogCRP on IMT(r(2)=0.36, p<0.001).

CONCLUSION

MS and low-grade chronic inflammation have an independent impact on vascular phenotype including IMT in DM2.

Assessment of the carotid artery by MRI at 3T: A study on reproducibility

PURPOSE

To examine the reproducibility of carotid artery dimension measurements using 3T MRI.

MATERIALS AND METHODS

Ten healthy volunteers underwent three scans on two occasions for assessment of total vessel wall area (TVWA), total luminal area (TLA), and minimum (MinT) and maximum (MaxT) vessel wall thickness. A double inversion-recovery (IR) fast gradient-echo (FGRE) sequence was used on a commercial 3T system. During the first visit the subjects were scanned twice. The third scan was performed at least four days later. One observer traced all scans, and a second observer retraced the first scan series.

RESULTS

For TVWA an interclass correlation (ICC) of 0.994 was calculated with all three scans taken into account. The interobserver ICC was 0.984. The agreement between the scans for TLA showed an ICC of 0.982 with an interobserver ICC of 0.998. For MinT and MaxT an ICC of 0.843 and 0.935 were calculated, with interobserver ICCs of 0.860 and 0.726, respectively.

CONCLUSION

With the use of a commercial 3T MR system, TVWA, TLA, and wall thickness measurements of the carotid artery can be assessed with good reproducibility.

The effect of prednisolone on serum sodium concentration

BACKGROUND

Glucocorticoids are widely used in clinical practice. In addition to their anti-inflammatory effects, they influence the salt and water homeostasis. Although parts of the latter action have been studied individually, there are no reports in stable outpatients on the net effect of glucocorticoids on serum sodium concentration.

METHODS

A group of 23 patients on chronic prednisolone therapy was compared with a control population with respect to serum sodium concentration. Intra-individual changes in serum sodium concentration after the initiation of prednisolone therapy were studied separately in 14 patients.

RESULTS

A significantly higher serum sodium level of 1.67mmol/L (P=0.03) was observed in the prednisolone-treated patients, whereas initiation of prednisolone was accompanied by an increase of 2.61mmol/L (P=0.004). The doses and duration of prednisolone therapy had no relation to the increase in serum sodium concentration.

CONCLUSION

Prednisolone therapy in stable outpatients results in a small, yet significant, increase in serum sodium concentration.

Left ventricular apical ballooning

Transient left ventricular apical ballooning is an acute cardiac syndrome characterised by an abrupt onset of chest pain and is usually associated with anterior electrocardiographic changes. The observed apical ballooning of the left ventricle is usually reversible and develops in the absence of significant atherosclerotic coronary artery disease. Here we present (to our knowledge) the first case of this syndrome in a negroid patient.