Validation of coala heart monitor

Background/Introduction

Atrial fibrillation (AF) can be asymptomatic and it is associated with stroke and heart failure which can present as first symptoms [1,2]. There is increasing evidence of benefits of screening for AF to prevent ischemic stroke by initiating anticoagulation therapy in affected individuals [3]. There are several devices used for screening of AF [4] and one of them is Coala Heart Monitor (CHM), which is a handheld device, connected by blue-tooth to a smartphone for registration of the rhythm from the chest and the thumbs. The aim with this this study was to validate the accuracy of CHM for detecting atrial tachyarrhythmia (ATA) (AF, atrial flutter or atrial tachycardia) compared to 12-lead-ECG.

Methods

Eligible participants were ≥18 years of age, planned for a 12-lead-ECG, with a history of ATA. Exclusion criteria were; pacemaker or implantable cardioverter-defibrillator (ICD)-treatment, ongoing arrhythmia that was not ATA or if the patient was unwilling or unable to provide informed consent. One hundred and eleven 12-lead-ECG were collected and immediately after a 30 + 30 second thumb-and chest-registration from CHM where collected. 12-lead-ECG independently interpreted by two electrophysiologist was used as the reference standard (100% coherence). In one patient neither chest nor thumb-registration could be interpreted due to bad quality, and this was not included in the analysis. Eight thumb-registrations and three chest-registrations could not be interpreted and in these cases the other registration could be interpreted. In one case there was disagreement between interpreter one and two, and in this case a third interpreter was involved.

Results

Mean age was 65.2±12.1 years and 28.8% were female. Prevalence of ATA was 36.4%. The sensitivity for ATA was 100% (95% CI, 96.3% - 100%) and the specificity was 100% (95% CI, 96.3% - 100%).

Conclusion

CHM provides excellent sensitivity and specificity for ATA compared to 12-lead-ECG.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Swedish Research Council

Feasibility of a novel algorithm for automated reconstruction of the left atrial anatomy based on intracardiac echocardiography

Funding Acknowledgements

Type of funding sources: None.

Background

Intracardiac echocardiography (ICE) is frequently used to guide electrophysiology procedures. The novel pre-commercial automated algorithm is a model-based algorithm, developed using machine learning methodology, which reconstructs a 3D anatomy of the left atrium (LA) and its structures based on a set of 2D ultrasound (US) frames, without the need to manually annotate US contours. Potential advantages are shortening of mapping time and better anatomy resolution when compared to conventional anatomical mapping techniques.

Purpose

Determine the early feasibility of the automated LA anatomy algorithm in routine clinical setting.

Methods

We included 16 patients (64±9 years, 88% males, body mass index 27±3, parasternal long axis LA diameter 40±3mm) undergoing LA mapping/catheter ablation (conscious sedation in 56% and general anaesthesia in the remaining cases). 2D US frames were acquired from three ICE-positions: superior vena cava/high right atrium (RA) junction, RA and right ventricular outflow tract. The automated LA anatomy map was validated in two steps: 1) identification of anatomical structures (pulmonary veins [PV] and left atrial appendage) by alignment of the ablation catheter to the automated map; and 2) assessment of PV anatomical accuracy by analysing the relationship with the automated lesion tags (3mm lesion radius, 3mm for 8sec stability criteria and 5-20g average contact force) and the PV antrum of the automated map in 9 patients with paroxysmal atrial fibrillation undergoing first time point-by-point radiofrequency PV isolation (PVI). In step 2, PV pairs were divided into 6 segments (total of 12 segments per patient) and were classified as accurate, insufficient ("floating" lesion tags), or excessive anatomy (invisible lesion tags).

Results

Mean 2D US frames per patient was 29±6 and acquisition time was 16±4 min. In the step 1 validation, all anatomical structures were correctly identified in the 16 patients by the automated algorithm. The step 2 validation showed anatomical accuracy in 76% of all 108 PV segments analysed. There was a range of 0-2 and 0-5 of the total 12 segments per patient with insufficient and excessive anatomy, respectively. In all cases with PV segment anatomical discrepancy, this was corrected with standard anatomy collection with the ablation catheter in ≤2min. In the whole patient group, catheter ablation was successfully performed on the automated map without complications.

Conclusions

The automated ICE-based 3D LA map algorithm performed overall well and correctly identified the LA anatomical structures in all patients. Anatomical PV antrum accuracy was high, and the majority of PV segments needed no manual correction before proceeding to PVI.

Endurance training increases the risk of atrial fibrillation in women: a matched-cohort study

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): This work was supported by research grants from Kvinnor och Hälsa and The Swedish Research Council for Sport Science (to Nikola Drca).

Objective

Previous studies have found that vigorous physical activity, mainly related to endurance sport participation, increases the risk of atrial fibrillation (AF) in men. However, it remains unclear whether vigorous physical activity also influences the risk of AF in women. We aimed to examine whether endurance sport participation may affect AF risk in women.

Methods

We conducted a matched-cohort study of top Swedish female endurance athletes (n=228 marathon runners, cyclist, and 10 000-meters track runners) active between 1979-1991 and reference individuals (n=1 368) from the general population individually matched by sex, year of birth, and area of living with a 6:1 ratio to the female athletes. The athlete cohort was created by combining all Swedish women who ran the Stockholm Marathon faster than 3.25 hours in any of the races between 1979 and 1991 with all Swedish women competing in the Swedish athletic national championship in 10 000-meter track running and the top-ranked Swedish bicyclist during the same period. Participants were followed up from study entry until AF diagnosis, death, emigration, or December 31, 2017, whichever occurred first. We used the Swedish National Patient Register to determine whether the participants were diagnosed with AF and other covariables. Cox proportional hazards regression models were used for analysis.

Results

Baseline characteristics are presented in Table 1. Mean age at study entry was 32 (SD ± 8.5) years. During follow-up (mean 28.8 years; SD ± 4.4), 33 cases of AF were diagnosed, including 10 (4.4%) among athletes and 23 (1.7%) among references. Endurance training was associated with an increased AF risk (Figure 1). The hazard ratio for female athletes compared with the reference population was 2.56 (95% confidence interval 1.22 to 5.37) in the univariable model and 3.67 (95% confidence interval 1.71 to 7.87) after adjustment for hypertension.

Conclusion

High level of endurance sport training is associated with an increased risk of AF in women.

Low incidence of major complications after the first six hours post-atrial fibrillation ablation – same-day discharge safe and feasible in most patients

Background/Introduction

Catheter ablation of atrial fibrillation (AF) is associated with a complication risk. It is common practice to monitor patients overnight post-procedurally which is resource craving.

Purpose

To evaluate the incidence of procedural complications related to catheter ablation of AF to assess the potential feasibility and safety of same day discharge in a large cohort.

Methods

We performed an analysis of prospectively collected data of complications of all patients staying overnight after undergoing AF ablation between 2001 and 2020 at a tertiary centre. By studying medical records, we analysed complications occurring intraprocedurally until six hours post-ablation, and between six hours post-ablation until discharge the day after ablation procedure (up to 24 hours post-procedure).

Results

In 5414 AF ablations we identified a total of 108 (2.0%) major complications occurring intraprocedural or until discharge the day after procedure. Most major complications occurred early and were detected intraprocedurally or within six hours after completed procedure (n=96, 1.8%). Twelve (0.2%) major complications occurred between six hours post-ablation and until discharge the day after procedure. The most common of these were congestive heart failure (n=6) and transient ischemic attack (TIA, n=4). In addition, there were 61 (1.1%) minor complications which occurred in this time span. Factors independently associated with major complications intraprocedurally or within 24 hours were age (p=0.046), body mass index (BMI) ≥30 kg/m2 (p=0.009), significant valvular disease (p=0.001), cardiomyopathy (p<0.001), prior stroke or TIA (p=0.014), first time procedure vs. repeat procedure (p=0.013), cryoablation vs. radiofrequency (p<0.001) and procedure duration (p<0.001).

Conclusion

Very few complications occurred between six hours and until discharge after ablation of atrial fibrillation. Therefore, same-day discharge may be a safe option for a large proportion of patients.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Region Stockholm funding

Cryoablation as standard treatment of atrial flutter: a prospective, 2-center study (CASTAF)

BACKGROUND

Cryoablation (CRYO) of cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL) has been shown to be non-inferior to radiofrequency ablation (RF) in terms of ablation success and is associated with less pain. However, procedural time has been significantly longer with CRYO compared to RF. A possible explanation for this could be that operators had less experience with CRYO than with RF. The purpose of this study was to test the hypothesis that in the hands of experienced operators, cryoablation of CTI-dependent AFL is effective with procedure-time similar to what is reported for RF.

METHODS

This prospective 2-center study included 184 patients with CTI-dependent AFL - median age 66 years (range 28-83), 159 men (86%). Cryoablation was performed using a 9 F, 8 mm tip catheter (Freezor MAX, Medtronic, Inc, MN, USA). Ablation endpoint was bidirectional CTI-block. Pain was evaluated with a visual analogue scale (VAS 0-10). All operators had experience of at least 25 previous CTI-ablations with CRYO.

RESULTS

The acute success rate was 89%. Procedural time including an observation period of 30 min, was 115 ± 36 min which is similar to procedural times for RF in previous studies. Fluoroscopy time was 11 ± 9 min. Cryoablation was perceived as almost pain- free by the patients, VAS (mean) 1.8 ± 1.2. Success rate at 12-month follow-up (FU) was 88% in patients with primary success. No major adverse events occurred.

CONCLUSIONS

Cryoablation of CTI-dependent AFL is effective, with a low level of procedure-related pain. In experienced hands, the procedure time in this prospective non-randomised trial seems to be in the level of reported procedure times for RF. The long-term relapse rate appears to be higher than for RF.

Sinus heart rate post pulmonary vein ablation and long-term risk of recurrences

Aim

To investigate the association of sinus heart rate pre- and post-ablation and recurrence rates in patients undergoing catheter ablation for atrial fibrillation.

Methods

Between January 2012 and December 2017, data of 482 patients undergoing their first pulmonary vein isolation (PVI) were included. All patients were followed-up for 12 months and were screened for any atrial tachyarrhythmia. Sinus heart rate measurements were recorded before (PRE), directly post ablation (POST) and 3 months post ablation (3M).

Results

In the total study population, the mean resting sinus heart rate at PRE (mean 57.9 bpm (95% CI, 57.1–58.7 bpm)) increased by over 10 bpm to POST (mean 69.4 bpm (95% CI, 68.5–70.3 bpm); p<0.001) followed by a slight decrease at 3M (mean 67.3 bpm (95% CI, 66.4–68.2 bpm)) but still remaining higher compared to PRE (p<0.001). This pattern was observed in patients with and without recurrences at PRE, POST and 3M respectively (both p<0.001). However, only at 3M, there was a significant difference in mean heart rate being lower in patients with compared to patients without recurrences (p=0.031). In this regard, patients with a heart rate ≥60 bpm at 3M and a heart rate change ≥11 bpm (PRE to 3M) had a favorable outcome in terms of recurrences compared to the remaining patients (HR 0.61 (95% CI, 0.44–0.84), p=0.002 and HR 0.55 (95% CI, 0.40–0.76), p<0.001, respectively). These variables remained independently associated in multivariable analysis.

Conclusion

Our study confirms the impact of PVI on cardiac autonomic function with a significant heart increase post-ablation. A heart rate ≥60bpm at 3M and a heart rate change ≥11 bpm (PRE to 3M) are associated with a favorable outcome in terms of recurrences.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): German Research Foundation

Long-term outcome of patients with invasive electrophysiology procedure related cardiac tamponade

Aims

Iatrogenic cardiac tamponades are a rare but dreaded complication of invasive electrophysiology procedures (EPs). Their long-term impact on clinical outcomes is unknown. This study analyzed the risk of death or serious cardiovascular events in patients suffering from EP related cardiac tamponade requiring pericardiocentesis during long-term follow-up.

Methods and results

Out of 19997 invasive EPs at our university hospital between January 1998 and September 2018, all patients with EP related periprocedural cardiac tamponade were identified (n=60) and matched (1:3 ratio) to a control group (n=180). After a follow-up of 5 years, the composite primary end point - death from any cause, acute myocardial infarction, TIA/stroke and hospitalization for heart failure – occurred in significantly more patients in the tamponade than in the control group (12 patients (20.0%) vs 19 patients (10.6%); Hazard ratio (HR) 2.53 (95% CI, 1.15–5.58); p=0.021). This was mainly driven by a higher incidence of TIA/stroke in the tamponade than in the control group (HR 3.75 (95% CI, 1.01–13.97); p=0.049). Death from any cause, acute myocardial infarction and hospitalization for heart failure did not show a significant difference between the groups. Hospitalization for pericarditis occurred in significantly more patients in the tamponade than in the control group (HR 36.0 (95% CI, 4.68–276.86); p=0.001).

Conclusion

Patients with EP related cardiac tamponade are at higher risk for cerebrovascular events during the first two weeks and hospitalization for pericarditis during the first months after index procedure. Despite the increased risk for early complications tamponade patients have a good long-term prognosis without increased risk for mortality or other serious cardiovascular events.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): German Research Foundation

Exhaled nitric oxide partitioned into alveolar, lower airways and nasal contributions

During the last year exhaled nitric oxide (NO) has been proposed as a marker of airway inflammation. More knowledge of the production and transfer of this molecule are needed in order for NO analysis to become a clinical tool. This was the aim of the study. Exhaled NO values from multiple flow rates were used to model alveolar NO, transfer rate and tissue concentration of NO in the airways. Three flows rates, 0.005, 0.1 and 0.51 sec(-1) were found to be optimal. The NO transfer rate of the airways was 9 +/- 2 ml sec(-1), the tissue source was 75 +/- 28 ppb and the alveolar fraction of NO was 2 +/- 1 ppb in 10 healthy subjects (mean +/- CI95%). In conclusion, we have shown that it is possible to get more information about the distribution of NO in the lungs and the airways than only a single value from one expiratory flow rate can give. Further studies will reveal if this airway modelling can be useful in disease of the respiratory system.