Accuracy in detecting atrial fibrillation in single-lead ECGs: an online survey comparing the influence of clinical expertise and smart devices

BACKGROUND

Manual interpretation of single-lead ECGs (SL-ECGs) is often required to confirm a diagnosis of atrial fibrillation. However accuracy in detecting atrial fibrillation via SL-ECGs may vary according to clinical expertise and choice of smart device.

AIMS

To compare the accuracy of cardiologists, internal medicine residents and medical students in detecting atrial fibrillation via SL-ECGs from five different smart devices (Apple Watch, Fitbit Sense, KardiaMobile, Samsung Galaxy Watch, Withings ScanWatch). Participants were also asked to assess the quality and readability of SL-ECGs.

METHODS

In this prospective study (BaselWearableStudy, NCT04809922), electronic invitations to participate in an online survey were sent to physicians at major Swiss hospitals and to medical students at Swiss universities. Participants were asked to classify up to 50 SL-ECGs (from ten patients and five devices) into three categories: sinus rhythm, atrial fibrillation or inconclusive. This classification was compared to the diagnosis via a near-simultaneous 12-lead ECG recording interpreted by two independent cardiologists. In addition, participants were asked their preference of each manufacturer's SL-ECG.

RESULTS

Overall, 450 participants interpreted 10,865 SL-ECGs. Sensitivity and specificity for the detection of atrial fibrillation via SL-ECG were 72% and 92% for cardiologists, 68% and 86% for internal medicine residents, 54% and 65% for medical students in year 4-6 and 44% and 58% for medical students in year 1-3; p <0.001. Participants who stated prior experience in interpreting SL-ECGs demonstrated a sensitivity and specificity of 63% and 81% compared to a sensitivity and specificity of 54% and 67% for participants with no prior experience in interpreting SL-ECGs (p <0.001). Of all participants, 107 interpreted all 50 SL-ECGs. Diagnostic accuracy for the first five interpreted SL-ECGs was 60% (IQR 40-80%) and diagnostic accuracy for the last five interpreted SL-ECGs was 80% (IQR 60-90%); p <0.001. No significant difference in the accuracy of atrial fibrillation detection was seen between the five smart devices; p = 0.33. SL-ECGs from the Apple Watch were considered as having the best quality and readability by 203 (45%) and 226 (50%) participants, respectively.

CONCLUSION

SL-ECGs can be challenging to interpret. Accuracy in correctly identifying atrial fibrillation depends on clinical expertise, while the choice of smart device seems to have no impact.

Transvenous Lead Extraction during Cardiac Implantable Device Upgrade: Results from the Multicenter Swiss Lead Extraction Registry

BACKGROUND

Device patients may require upgrade interventions from simpler to more complex cardiac implantable electronic devices. Prior to upgrading interventions, clinicians need to balance the risks and benefits of transvenous lead extraction (TLE), additional lead implantation or lead abandonment. However, evidence on procedural outcomes of TLE at the time of device upgrade is scarce.

METHODS

This is a post hoc analysis of the investigator-initiated multicenter Swiss TLE registry. The objectives were to assess patient and procedural factors influencing TLE outcomes at the time of device upgrades.

RESULTS

941 patients were included, whereof 83 (8.8%) had TLE due to a device upgrade. Rotational mechanical sheaths were more often used in upgraded patients (59% vs. 42.7%, p = 0.015) and total median procedure time was longer in these patients (160 min vs. 105 min, p < 0.001). Clinical success rates of upgraded patients compared to those who received TLE due to other reasons were not different (97.6% vs. 93.0%, p = 0.569). Moreover, multivariable analysis showed that upgrade procedures were not associated with a greater risk for complications (HR 0.48, 95% confidence interval 0.14-1.57, p = 0.224; intraprocedural complication rate of upgraded patients 7.2% vs. 5.5%). Intraprocedural complications of upgraded patients were mostly associated with the implantation and not the extraction procedure (67% vs. 33% of complications).

CONCLUSIONS

TLE during device upgrade is effective and does not attribute a disproportionate risk to the upgrade procedure.

Follow-up of CRT-D patients downgraded to CRT-P at the time of generator exchange

Background

Some patients with cardiac resynchronisation therapy (CRT) experience super-response (LVEF improvements to ≥50%). At generator exchange (GE), downgrading (DG) from CRT-defibrillator (CRT-D) to CRT-pacemaker (CRT-P) could be an option for these patients on primary prevention ICD indication and no required ICD therapies. Long-term data on arrhythmic events in super-responders is scarce.

Methods

CRT-D patients with LVEF improvement to ≥50% at GE were identified in four large centres for retrospective analysis. Mortality, significant ventricular tachyarrhythmia and appropriate ICD-therapy were determined, and patient analysis was split into two groups (downgraded to CRT-P or not).

Results

Sixty-six patients (53% male, 26% coronary artery disease) on primary prevention were followed for a median of 129 months [IQR: 101-155] after implantation. 27 (41%) patients were downgraded to CRT-P at GE after a median of 68 [IQR: 58-98] months (LVEF 54% ± 4%). The other 39 (59%) continued with CRT-D therapy (LVEF 52% ± 6%). No cardiac death or significant arrhythmia occurred in the CRT-P group (median follow-up (FU) 38 months [IQR: 29-53]). Three appropriate ICD-therapies occurred in the CRT-D group [median FU 70 months (IQR: 39-97)]. Annualized event-rates after DG/GE were 1.5%/year and 1.0%/year in the CRT-D group and the whole cohort, respectively.

Conclusions

No significant tachyarrhythmia were detected in the patients downgraded to CRT-P during follow-up. However, three events were observed in the CRT-D group. Whilst downgrading CRT-D patients is an option, a small residual risk for arrhythmic events remains and decisions regarding downgrade should be made on a case-by-case basis.

Ventricular pacing burden in patients with left bundle branch block after transcatheter aortic valve replacement therapy

INTRODUCTION

Electrophysiological testing has been proposed in the latest European Society of Cardiology (ESC) guidelines for cardiac pacing to identify left bundle branch block (LBBB) patients with infrahisian conduction delay (IHCD) after transcatheter aortic valve replacement (TAVR). While in general IHCD is defined by a His-ventricular (HV) interval of >55 ms, a cut-off of ≥70 ms to trigger pacemaker (PM) implantation has been proposed in the latest ESC guidelines. The ventricular pacing (VP) burden during follow-up in such patients is largely unknown. As such, we aimed to assess the VP burden during follow-up of patients receiving PM therapy for LBBB after TAVR based on an HV interval > 55 ms and ≥70 ms.

METHODS

All patients with new-onset or pre-existing LBBB after undergoing TAVR at a tertiary referral center underwent EP testing the day after TAVR. In patients with a prolonged HV interval (>55 ms), PM implantation was performed by a trained electrophysiologist in a standardized fashion. All devices were programmed to avoid unnecessary VP by specific algorithms (e.g., AAI-DDD).

RESULTS

701 patients underwent TAVR at the University Hospital of Basel. One hundred seventy-seven patients presented with new-onset or pre-existing LBBB the day following TAVR and underwent EP testing. An HV interval > 55 ms was found in 58 patients (33%) and an HV interval ≥ 70 ms in 21 patients (12%). 51 patients (mean age 84 ± 6.2 years, 45% women) agreed to receive a PM, out of which 20 (39%) patients had an HV Interval over 70 ms. Atrial fibrillation was present in 53% of the patients. A dual chamber PM was implanted in 39 (77%), and a single chamber PC in 12 (23%) patients, respectively. Median follow-up was 21 months. The median VP burden overall was 3%. The median VP burden was not significantly different between patients with an HV ≥ 70 ms (6.5 [0.8-52]) and those with an HV between 55 and 69 ms (2 [0-17], p = .23). 31% of patients demonstrated a VP burden < 1%, 27% 1%-5% and 41% > 5%. The median HV intervals in patients with VP burdens < 1%, 1%-5% and >5% were 66 (IQR 62-70) ms, 66 (IQR 63-74) ms and 68 (IQR 60-72) ms, respectively, p = .52. When only assessing patients with an HV interval 55-69 ms, 36% demonstrated a VP burden of <1%, 29% of 1%-5% and 35% of >5%. In patients with an HV Interval ≥ 70 ms, 25% demonstrated a VP burden < 1%, 25% of 1%-5% and 50% of >5% %, p = .64 (Figure).

CONCLUSION

In patients with LBBB after TAVR and IHCD defined by an HV interval > 55 ms, VP burden is relevant in a non-negligible amount of patients during follow-up. Further studies are warranted to define the optimal cut-off value for the HV interval or to develop risk models incorporating HV measurements and other risk factors to trigger PM implantation in patients with LBBB after TAVR.

Atrial substrate characterization based on bipolar voltage electrograms acquired with multipolar, focal and mini-electrode catheters

BACKGROUND

Bipolar voltage (BV) electrograms for left atrial (LA) substrate characterization depend on catheter design and electrode configuration.

AIMS

The aim of the study was to investigate the relationship between the BV amplitude (BVA) using four catheters with different electrode design and to identify their specific LA cutoffs for scar and healthy tissue.

METHODS AND RESULTS

Consecutive high-resolution electroanatomic mapping was performed using a multipolar-minielectrode Orion catheter (Orion-map), a duo-decapolar circular mapping catheter (Lasso-map), and an irrigated focal ablation catheter with minielectrodes (Mifi-map). Virtual remapping using the Mifi-map was performed with a 4.5 mm tip-size electrode configuration (Nav-map). BVAs were compared in voxels of 3 × 3 × 3 mm3. The equivalent BVA cutoff for every catheter was calculated for established reference cutoff values of 0.1, 0.2, 0.5, 1.0, and 1.5 mV. We analyzed 25 patients (72% men, age 68 ± 15 years). For scar tissue, a 0.5 mV cutoff using the Nav corresponds to a lower cutoff of 0.35 mV for the Orion and of 0.48 mV for the Lasso. Accordingly, a 0.2 mV cutoff corresponds to a cutoff of 0.09 mV for the Orion and of 0.14 mV for the Lasso. For healthy tissue cutoff at 1.5 mV, a larger BVA cutoff for the small electrodes of the Orion and the Lasso was determined of 1.68 and 2.21 mV, respectively.

CONCLUSION

When measuring LA BVA, significant differences were seen between focal, multielectrode, and minielectrode catheters. Adapted cutoffs for scar and healthy tissue are required for different catheters.

Clinical Validation of 5 Direct-to-Consumer Wearable Smart Devices to Detect Atrial Fibrillation: BASEL Wearable Study

BACKGROUND

Multiple smart devices capable to detect atrial fibrillation (AF) are presently available. Sensitivity and specificity for the detection of AF may differ between available smart devices, and this has not yet been adequately investigated.

OBJECTIVES

The aim was to assess the accuracy of 5 smart devices in identifying AF compared with a physician-interpreted 12-lead electrocardiogram as the reference standard in a real-world cohort of patients.

METHODS

We consecutively enrolled patients presenting to a cardiology service at a tertiary referral center in a prospective, diagnostic study.

RESULTS

We prospectively analyzed 201 patients (31% women, median age 66.7 years). AF was present in 62 (31%) patients. Sensitivity and specificity for the detection of AF were comparable between devices: 85% and 75% for the Apple Watch 6, 85% and 75% for the Samsung Galaxy Watch 3, 58% and 75% for the Withings Scanwatch, 66% and 79% for the Fitbit Sense, and 79% and 69% for the AliveCor KardiaMobile, respectively. The rate of inconclusive tracings (the algorithm was unable to determine the heart rhythm) was 18%, 17%, 24%, 21%, and 26% for the Apple Watch 6, Samsung Galaxy Watch 3, Withings Scan Watch, Fitbit Sense, and AliveCor KardiaMobile (P < 0.01 for pairwise comparison), respectively. By manual review of inconclusive tracings, the rhythm could be determined in 955 (99%) of 969 single-lead electrocardiograms. Regarding patient acceptance, the Apple Watch was ranked first (39% of participants).

CONCLUSIONS

In this clinical validation of 5 direct-to-consumer smart devices, we found differences in the amount of inconclusive tracings diminishing sensitivity and specificity of the smart devices. In a clinical setting, manual review of tracings is required in about one-fourth of cases.

Sense-B-noise: an enigmatic cause for inappropriate shocks in subcutaneous implantable cardioverter defibrillators

AIMS

Subcutaneous implantable cardioverter defibrillators (S-ICDs) are well established. However, inappropriate shocks (IAS) remain a source of concern since S-ICDs offer very limited troubleshooting options. In our multicentre case series, we describe several patients who experienced IAS due to a previously unknown S-ICD system issue.

METHODS AND RESULTS

We observed six patients suffering from this novel IAS entity. The IAS occurred exclusively in primary or alternate S-ICD sensing vector configuration (therefore called 'Sense-B-noise'). IAS were caused by non-physiologic oversensing episodes characterized by intermittent signal saturation, diminished QRS amplitudes, and disappearance of the artefacts after the IAS. Noise/oversensing could not be provoked by manipulation, X-ray did not show evidence for lead/header issues and impedance measurements were within normal limits. The pooled experience of our centres implies that up to ∼5% of S-ICDs may be affected. The underlying root cause was discussed extensively with the manufacturer but remains unknown and is under further investigation.

CONCLUSION

Sense-B-noise is a novel cause for IAS due to non-physiologic signal oversensing, arising from a previously unknown S-ICD system issue. Sense-B-noise may be suspected if episodes of signal saturation in primary or alternate vector configuration are present, oversensing cannot be provoked, and X-ray and electrical measurements appear normal. The issue can be resolved by reprogramming the device to secondary sensing vector.

Value of Periprocedural Electrophysiology Testing During Transcatheter Aortic Valve Replacement for Risk Stratification of Patients With New-Onset Left Bundle-Branch Block

Background Despite being the most frequent complication following transcatheter aortic valve replacement (TAVR), optimal management of left bundle-branch block (LBBB) remains unknown. Electrophysiology study has been proposed for risk stratification. However, the optimal timing of electrophysiology study remains unknown. We aimed to investigate the temporal dynamics of atrioventricular conduction in patients with new-onset LBBB after TAVR by performing serial electrophysiology study and to deduce a treatment strategy. Methods and Results We assessed consecutive patients undergoing TAVR via His-ventricular interval measurement prevalve and postvalve deployment and the day after TAVR. Infranodal conduction delay was defined as a His-ventricular interval >55 milliseconds. Among 107 patients undergoing TAVR, 53 patients (50%) experienced new-onset LBBB postvalve deployment and infranodal conduction delay was noted in 24 of 53 patients intraprocedurally (45%). LBBB resolved the day after TAVR in 35 patients (66%). In patients with new-onset LBBB postvalve deployment and no infrahisian conduction delay intraprocedurally, the His-ventricular interval did not prolong in any patient to >55 milliseconds the following day. Overall, 4 patients (7.5%) with new-onset LBBB after TAVR were found to have persistent infrahisian conduction delay 24 hours after TAVR. During 30-day follow-up, 1 patient (1.1%) with new LBBB and a normal His-ventricular interval after TAVR developed new high-grade atrioventricular block. Conclusions Among patients with new-onset LBBB postvalve deployment, infrahisian conduction delay can safely be excluded intraprocedurally, suggesting that early intracardiac intraprocedural conduction studies may be of value in these patients.

Clinical Validation of Automated Corrected QT-Interval Measurements From a Single Lead Electrocardiogram Using a Novel Smartwatch

Introduction

The Withings Scanwatch (Withings SA, Issy les Moulineaux, France) offers automated analysis of the QTc. We aimed to compare automated QTc-measurements using a single lead ECG of a novel smartwatch (Withings Scanwatch, SW-ECG) with manual-measured QTc from a nearly simultaneously recorded 12-lead ECG.

Methods

We enrolled consecutive patients referred to a tertiary hospital for cardiac workup in a prospective, observational study. The QT-interval of the 12-lead ECG was manually interpreted by two blinded, independent cardiologists through the tangent-method. Bazett’s formula was used to calculate QTc. Results were compared using the Bland-Altman method.

Results

A total of 317 patients (48% female, mean age 63 ± 17 years) were enrolled. HR-, QRS-, and QT-intervals were automatically calculated by the SW in 295 (93%), 249 (79%), and 177 patients (56%), respectively. Diagnostic accuracy of SW-ECG for detection of QTc-intervals ≥ 460 ms (women) and ≥ 440 ms (men) as quantified by the area under the curve was 0.91 and 0.89. The Bland-Altman analysis resulted in a bias of 6.6 ms [95% limit of agreement (LoA) –59 to 72 ms] comparing automated QTc-measurements (SW-ECG) with manual QTc-measurement (12-lead ECG). In 12 patients (6.9%) the difference between the two measurements was greater than the LoA.

Conclusion

In this clinical validation of a direct-to-consumer smartwatch we found fair to good agreement between automated-SW-ECG QTc-measurements and manual 12-lead-QTc measurements. The SW-ECG was able to automatically calculate QTc-intervals in one half of all assessed patients. Our work shows, that the automated algorithm of the SW-ECG needs improvement to be useful in a clinical setting.

Healthy lifestyle and atrial fibrillation recurrence after pulmonary vein isolation

Funding Acknowledgements

Type of funding sources: None.

Background/Introduction: Data on the relationship of a healthy lifestyle at the time of atrial fibrillation (AF) ablation with AF recurrence is limited.

Purpose

We investigated the association of healthy lifestyle markers with AF recurrence after ablation.

Methods

In 1439 patients undergoing AF ablation at a tertiary university hospital, a lifestyle score was built. The score included categories of BMI, smoking, blood pressure, fish intake, fruits/vegetable intake, alcohol consumption and physical activity. A higher score indicated a healthier lifestyle and patients were grouped into tertiles. Follow-up included 24h-Holter ECGs at 3 and 6 months and 7d-Holter ECGs at 12 months. Survival analyses and Cox-regression models were used to assess associations of individual factors and score-tertiles with AF recurrence.

Results

Mean age was 61.5 years, 25.9% were female and 59.1% had paroxysmal AF. In 941 patients all lifestyle score variables were available: 129, 675 and 137 patients were in the low, intermediate and high lifestyle group, respectively. Over increasing lifestyle groups, patients were more often female (9.3, 23.3, 38.7%; p&lt;0.0001), had less hypertension (70.5, 53.3, 32.9%; p&lt;0.0001), diabetes (15.5, 6.2, 3.7%; p=0.0002), a smaller left atrial diameter (44.1, 41.0, 37.6mm; p&lt;0.0001) and numerically more paroxysmal AF (56.6, 62.4, 69.4%; p=0.32) with no differences in anti-arrhythmic drugs. In survival analyses (Figure), we saw a trend of more recurrences in the healthiest group compared to the unhealthiest group (logrank p=0.06 for low vs high group). Individually, higher fish intake (logrank p=0.04) and lower blood pressure (logrank p=0.02) were associated with AF recurrence. In Cox-regression models the HR (95% CI) for increasing lifestyle groups was 1.21 (0.98; 1.50, p=0.07). In individual models only higher fish intake (1.25 [1.01; 1.55], p=0.045) was associated with AF recurrence.

Conclusion(s): AF recurrence was numerically more frequent in patients with a healthier lifestyle, despite less comorbidities and smaller LA diameters. This paradoxical relationship might be due to lifestyle changes after PVI, differences in PVI efficacy or residual confounding. Further studies are needed to better understand this association.

Clinical validation of a novel smartwatch for automated detection of atrial fibrillation

Funding Acknowledgements

Type of funding sources: None.

Introduction

The Withings Scanwatch is a novel smartwatch able to record an intelligent (i)ECG with automated detection of AF. While the iECG function from three major manufacturers have been extensively investigated, there is a paucity of data regarding the performance of the iECG function of the Withings Scanwatch.

Methods

We performed a prospective, observational study enrolling consecutive patients presenting to a cardiology service at a tertiary referral center. The aim was to assess the diagnostic performance of the iECG function of the Withings Scanwatch to detect AF compared to a simultaneously acquired cardiologist-interpreted 12-lead ECG. All iECG rhythm strips and 12-lead ECGs were anonymized and distributed to two blinded cardiologists who independently interpreted each tracing and assigned a diagnosis of sinus rhythm, AF or unclassified.

Results

iECGs and 12-lead ECGs were simultaneously recorded in 319 patients (67 yo (IQR 54-76), 48% female, Figure 1). Using the automated algorithm, rhythm was deemed inconclusive in 44 patients (14%). Overall, AF was present in 34 patients (11%). Among the tracings where the algorithm provided a diagnosis, it correctly identified AF with 76% (95%CI 55-91%) sensitivity, 99% (95%CI 97-100%) specificity, and a Kappa (K) coefficient of 0.72 when compared with cardiologist-interpreted 12-lead ECGs. Among patients in sinus rhythm, 3 were labeled AF (false-positive). From the 44 unclassified recordings, blinded cardiologists were able to correctly diagnose AF with 100% (95%CI 59-100%) sensitivity, 93% (95%CI 77-99%) specificity, and a K coefficient of 0.49. A total of 13 iECG recordings (4.1%) were determined to be noninterpretable by the cardiologists. Of the remaining 306 patients with simultaneous recordings, cardiologist interpretation of the iECG tracings demonstrated 97% (95%CI 84-100%) sensitivity, 99% (95%CI 96-100%) specificity and a K coefficient of 0.75.

Conclusion

Automatic rhythm classification was inferior to manual interpretation of iECGs. We found a lower sensitivity for the detection of AF using the Withings iECG function compared to data published on other devices. Cardiologist-iECG interpretation, however, was highly reliable with a diagnostic accuracy of 98% (95%CI 96-100%). Clinical interpretation of iECG readings by a cardiologist is therefore strongly encouraged

Leadless pacemaker implantation quality: importance of the operator's experience

AIMS

Leadless cardiac pacemaker (PM) implantation differs from conventional PM implantation. While the procedure has been considered safe, recent real-world data raised concerns about the learning curve of new operators and their implantation quality. The goal of this study was to investigate the influence of the first operator's experience on leadless PM implantation quality and procedural efficiency.

METHODS AND RESULTS

We performed a bicentric analysis of all Micra TPS™ implantations in two large tertiary referral hospitals. We assessed both leadless PM implantation quality based on the absence of complications (requiring intervention or prolonged hospitalization), good electrical performance (pacing threshold ≤ 1.5 V/0.24 ms, R-wave amplitude > 5 mV), and acceptable fluoroscopy duration (<10 min) as well as procedural efficiency in relation to the operator's experience. Univariate and multivariate logistic regression analyses were performed to identify predictors for implantation quality and procedural efficiency. Leadless PM implantation was successful in 106/111 cases (95.5%). Three patients (2.7%) experienced acute complications (one cardiac tamponade, one femoral bleeding, one posture-related PM exit block). Multivariate analysis showed that implantation quality of more experienced first operators was higher [odds ratio 1.09 (95% confidence interval 1.00-1.19), P = 0.05]. Procedural efficiency increased with operator experience as evidenced by an inverse correlation of procedure time, time to the first deployment, fluoroscopy time, and the number of procedures performed (all P < 0.05).

CONCLUSION

The operator's learning curve is a critical factor for leadless PM implantation quality and procedural efficiency.

Cryoballoon Ablation of Atrial Fibrillation Without Demonstration of Pulmonary Vein Occlusion-The Simplify Cryo Study

Background: The demonstration of pulmonary vein (PV) occlusion is routinely performed and considered a prerequisite for successful cryoballoon (CB) ablation of atrial fibrillation (AF). The purpose of this study was to assess the feasibility and impact on procedural parameters and outcome of a standardized procedural protocol without demonstrating PV occlusion.

Methods and Results: Consecutive patients undergoing CB pulmonary vein isolation (PVI) were studied. After cMRI assessment, patients treated by PVI using a novel no-contrast (NC) protocol without routine contrast injections to demonstrate PV occlusion (NC group) were compared to patients undergoing PVI with contrast injections to demonstrate PV occlusion (standard group). One hundred patients with paroxysmal or persistent AF (age 61 ± 10 years, ejection fraction 59 ± 11%, left atrial volume index 37.2 ± 2.0 mL/m²) were studied. The NC protocol was feasible in 72 of 75 patients (96%). Total procedure time and fluoroscopy time were 64.0 ± 14.1 min and 11.0 ± 4.6 min in the NC group and 92.0 ± 25.3 min and 18.0 ± 6.0 min in the standard group, respectively (all p < 0.001). Dose area product was 368 ± 362 cGy^*cm² in the NC group compared to 1928 ± 1541 cGy^*cm² in the standard group (p < 0.001). Forty-five of 75 patients (60%) in the NC group and 16 of 25 patients (64%) in the standard group remained in stable sinus rhythm after a single PVI and a 1-year follow-up (p = 0.815).

Conclusions: Performing CB ablation without using contrast injections to demonstrate PV occlusion was feasible, resulted in reduced radiation exposure, and increased the efficiency of the procedure.

Gender-related differences in patient selection for and outcomes after pace and ablate for refractory atrial fibrillation: insights from a large multicenter cohort

Funding Acknowledgements

Type of funding sources: None.

Background

A pace & ablate strategy may be performed in cases of severe refractory atrial arrhythmias.

Purpose

We aimed to assess gender related differences in patient selection and clinical outcomes after pace & ablate.

Methods

In a retrospective multicenter study, patients undergoing AV-junction-ablation between 2011 and 2019 were studied. Gender-related differences in terms of baseline characteristics, device-related complications, heart failure (HF) hospitalisations and death were assessed.

Results

Overall, 513 patients underwent AV-junction-ablation (median age 75 years, 50% males). At baseline, male patients were younger (72 vs. 78 years, p &lt; 0.001), more frequently had non-paroxysmal AF (82% vs. 72%, p = 0.006), a lower LVEF (35% vs. 55%, p &lt; 0.001) and more often received biventricular stimulation (75% vs. 25%, p &lt; 0.001). Interventional complications were rare in both gender (1.2% vs 1.6%, p = 0.72). Following AV-junction-ablation, improvement of EHRA-class by ≥1 and of LVEF by ≥5% occurred in 44% and 19% of patients respectively, without gender differences (p = 0.66 and p = 0.38). Patients were followed for a median of 42 months in survivors (IQR 22-62). Lead-related complications (11 patients, 2.1%), infections (1 patient, 0.2%) and upgrade to ICD or CRT (18 patients, 3.5%) were rare. In Kaplan Meier analysis, HF hospitalisations during 4 years of follow-up were more common in men (22% vs 11%, p = 0.02), as were death (28% vs 21%, p = 0.02) and the combination of death or HF hospitalisation (37% vs. 26%, p = 0.008, Figure). Gender remained an independent predictor of the combined endpoint of death or HF hospitalisation after adjustment for age, LVEF and type of stimulation.

Conclusion

A Pace & Ablate strategy is safe and results in improvement of EHRA class and LVEF in a substantial number of patients. We found significant gender differences in patient selection for pace & ablate. Female patients had a more favorable clinical course after AV-junction-ablation, which was independent of age, EF and type of stimulation. Abstract Figure. Comb. endpoint of death or heart failure

Efficacy and safety of a high power short duration ablation-index guided protocol for pulmonary vein isolation using a single catheter

Funding Acknowledgements

Type of funding sources: None.

Background

Catheter ablation for atrial fibrillation (AF) is the most common performed electrophysiological procedure. The cost of this procedure remains high.

Purpose

To improve health care utilization, we aimed to compare the efficacy and safety of a minimalistic, streamlined single radiofrequency catheter ablation approach using high power short duration ablation-index guided protocol (HPSD) vs. a standard single catheter protocol.

Methods

A circular mapping catheter free PVI with a single transseptal puncture was performed in 91 patients. A CARTO fast anatomical map was performed with the ablation catheter. Pacing maneuvers were used to confirm exit block. Procedural characteristics and success rates were compared using HPSD- vs. a standard ablation-protocol. Freedom from recurrence was defined as a 1-year absence of AF episodes &gt; 30 s, beyond the 3-month-blanking-period.

Results

Using the HPSD-protocol the median procedure, map and RF ablation time were significantly shorter in the HPSD group compared to the standard group, 84 (IQR 76-100) vs. 118 minutes (IQR 104-141), 12 (IQR 10-16) vs. 18 minutes (IQR 15-21) and 1036 (898-1184) vs. 1949 seconds (IQR 1693-2261), respectively, P &lt; .001 for all. First-pass-PVI was achieved using the HPSD-protocol in 23 patients (74%) and the standard-protocol in 30 patients (53%), p = 0.08. Localization of conduction gaps are illustrated for the HPSD-protocol and the standard-protocol in Figure 1. The residual gap was identified using the ablation catheter only in all patients. No procedural complication were observed. At 12 months follow-up, 60 (89.6%) patients remained free from AF with no differences between groups.

Conclusions

A minimalistic, CMC-free HPSD-guided PVI approach is very efficient, safe, likely cost-saving, and associated with excellent clinical outcomes at 1 year. Abstract Figure 1

Out-of-hospital cardiac arrest due to idiopathic ventricular fibrillation in patients with normal electrocardiograms: results from a multicentre long-term registry

AIMS 

To define the clinical characteristics and long-term clinical outcomes of a large cohort of patients with idiopathic ventricular fibrillation (IVF) and normal 12-lead electrocardiograms (ECGs).

METHODS AND RESULTS

Patients with ventricular fibrillation as the presenting rhythm, normal baseline, and follow-up ECGs with no signs of cardiac channelopathy including early repolarization or atrioventricular conduction abnormalities, and without structural heart disease were included in a registry. A total of 245 patients (median age: 38 years; males 59%) were recruited from 25 centres. An implantable cardioverter-defibrillator (ICD) was implanted in 226 patients (92%), while 18 patients (8%) were treated with drug therapy only. Over a median follow-up of 63 months (interquartile range: 25-110 months), 12 patients died (5%); in four of them (1.6%) the lethal event was of cardiac origin. Patients treated with antiarrhythmic drugs only had a higher rate of cardiovascular death compared to patients who received an ICD (16% vs. 0.4%, P = 0.001). Fifty-two patients (21%) experienced an arrhythmic recurrence. Age ≤16 years at the time of the first ventricular arrhythmia was the only predictor of arrhythmic recurrence on multivariable analysis [hazard ratio (HR) 0.41, 95% confidence interval (CI) 0.18-0.92; P = 0.03].

CONCLUSION 

Patients with IVF and persistently normal ECGs frequently have arrhythmic recurrences, but a good prognosis when treated with an ICD. Children are a category of IVF patients at higher risk of arrhythmic recurrences.

Use of the wearable cardioverter-defibrillator - the Swiss experience

INTRODUCTION

Sudden cardiac death caused by malignant arrhythmia can be prevented by the use of defibrillators. Although the wearable cardioverter defibrillator (WCD) can prevent such an event, its role in clinical practice is ill defined. We investigated the use of the WCD in Switzerland with emphasis on prescription rate, therapy adherence and treatment rate.

MATERIALS AND METHODS

The Swiss WCD Registry is a retrospective observational registry including patients using a WCD. Patients were included from the first WCD use in Switzerland until February 2018. Baseline characteristics and data on WCD usage were examined for the total study population, and separately for each hospital.

RESULTS

From 1 December 2011 to 18 February 2018, a total of 456 patients (67.1% of all WCDs prescribed in Switzerland and 81.1% of all prescribed in the participating hospitals) were included in the registry. Up to 2017 there was a yearly increase in the number of prescribed WCDs to a maximum of 271 prescriptions per year. The mean age of patients was 57 years (&plusmn; 14), 81 (17.8%) were female and mean left ventricular ejection fraction (EF) was 32% (&plusmn; 13). The most common indications for WCD use were new-onset ischaemic cardiomyopathy (ICM) with EF &le;35% (206 patients, 45.2%), new-onset nonischaemic cardiomyopathy (NICM) with EF &le;35% (115 patients, 25.2%), unknown arrhythmic risk (83 patients, 18.2%), bridging to implantable cardioverter-defibrillator implantation or heart transplant (37 patients, 8.1%) and congenital/inherited heart disease (15 patients, 3.3%). Median wear duration was 58 days (interquartile range [IQR] 31&ndash;94) with a median average daily wear time of 22.6 hours (IQR 20&ndash;23.2). Seventeen appropriate therapies from the WCD were delivered in the whole population (treatment rate: 3.7%) to a total of 12 patients (2.6% of all patients). The most common underlying heart disease in patients with a treatment was ICM (13/17, 76.5%). There were no inappropriate treatments.

CONCLUSION

The use of WCDs has increased in Switzerland over the years for a variety of indications. There is high therapy adherence to the WCD, and a treatment rate comparable to previously published registry data. &nbsp.

Electrophysiology Testing to Stratify Patients With Left Bundle Branch Block After Transcatheter Aortic Valve Implantation

Background Left bundle branch block (LBBB) is common after transcatheter aortic valve implantation (TAVI) and is an indicator of subsequent high-grade atrioventricular block (HAVB). No standardized protocol is available to identify LBBB patients at risk for HAVB. The aim of the current study was to evaluate the safety and efficacy of an electrophysiology study tailored strategy in patients with LBBB after TAVI. Methods and Results We prospectively analyzed consecutive patients with LBBB after TAVI. An electrophysiology study was performed to measure the HV-interval the day following TAVI. In patients with normal His-ventricular (HV)-interval ≤55 ms, a loop recorder was implanted (ILR-group), whereas pacemaker implantation was performed in patients with prolonged HV-interval >55 ms (PM-group). The primary end point was occurrence of HAVB during a follow-up of 12 months. Secondary end points were symptoms, hospitalizations, adverse events because of device implantation or electrophysiology study, and death. Of 373 patients screened after TAVI, 56 patients (82±6 years, 41% male) with LBBB were included. HAVB occurred in 4 of 41 patients (10%) in the ILR-group and in 8 of 15 patients (53%) in the PM-group (P<0.001). We did not identify other predictors for HAVB than the HV interval. The negative predictive value for the cut-off of HV 55 ms to detect HAVB was 90%. No HAVB-related syncope occurred in the 2 groups. Conclusions An electrophysiology study tailored strategy to LBBB after TAVI with a cut-off of HV >55 ms is a feasible and safe approach to stratify patients with regard to developing HAVB during a follow-up of 12 months.

Man vs machine: Performance of manual vs automated electrocardiogram analysis for predicting the chamber of origin of idiopathic ventricular arrhythmia

BACKGROUND

Radiofrequency catheter ablation of idiopathic ventricular arrhythmias (VAs) is performed to eliminate symptoms and to prevent or reverse arrhythmia-induced cardiomyopathy. Preprocedural prediction of the chamber of VA origin is critical for patient counseling, procedure planning, and guidance of invasive mapping.

OBJECTIVE

We aimed to assess the performance of manual expert versus automated 12-lead electrocardiogram (ECG) analysis in the prediction of VA origin.

METHODS

Patients with ablation of idiopathic VA and sustained success were included. The VA origin was defined as the site where ablation caused arrhythmia suppression. Standard baseline 12-lead ECGs with documentation of the VA were analyzed manually in a blinded fashion by three electrophysiologists and three electrophysiology (EP) fellows. In addition, the same standard 12-lead ECG was analyzed by an automated computer algorithm using a vectorcardiographic approach.

RESULTS

Thirty-eight patients (median age, 47 [interquartile range, 37-58]; 68% female) were enrolled. The VA originated from the right ventricle in 24 (63%) and the left ventricle in 14 (37%) patients. The electrophysiologists and EP fellows identified the VA chamber of origin with a similar accuracy of 73% and 72% (P = .72). The automated algorithm showed a higher accuracy of 89% (P = .03 compared with electrophysiologists and EP fellows). This resulted in a sensitivity of 95% and specificity of 86%.

CONCLUSION

While the manual ECG analysis of the standard 12-lead ECG by both electrophysiologists and EP fellows correctly identified the chamber of VA origin in around 75% of cases, an automated vectorcardiographic computer algorithm achieved an accuracy of 89% with clinically acceptable diagnostic parameters.

Ablation of typical atrial flutter guided by the paced PR interval on the surface electrocardiogram: a proof of concept study

AIMS

We aimed to assess the novel concept of using the paced PR interval (PRI) on the surface electrocardiogram (ECG) to prove trans-isthmus block after cavotricuspid isthmus (CTI) ablation for typical atrial flutter (AFl).

METHODS AND RESULTS

Consecutive patients with AFl underwent linear radiofrequency ablation of the inferior CTI (6 o'clock). After AFl termination and/or presumed completion of the CTI line, CTI block was proven by atrial pacing by the ablation catheter medial (5 o'clock) and lateral to the line (7 and 9 o'clock). Corresponding PRIs were measured on the surface ECG. CTI block was assumed, if a sudden increase in the PRI was observed by moving the pacing site from 5 to 7 o'clock, and if the latter was longer than at 9 o'clock. Afterwards, bidirectional CTI block was confirmed by differential pacing. Thirty-one patients (mean age 67 ± 16 years, 81% male) underwent CTI ablation, and 18/31 (58%) were in AFl at the time of ablation (cycle length 249 ± 31 ms). Successful CTI block as defined by the PRI method was achieved in 31/31 (100%), and the mean PRIs during pacing at 5, 7, and 9 o'clock were 203 ± 56 ms, 329 ± 70 ms, and 296 ± 66 ms, respectively. Cavotricuspid isthmus block was confirmed in all patients (100%) by coronary sinus pacing with a reversal of the local activation sequence lateral to the isthmus line.

CONCLUSION

The method of PRI analysis on the surface ECG to guide CTI ablation is easy to apply and highly accurate in confirming CTI block. This simple technique enables the novel concept of CTI ablation and proof of block with a single catheter.

Prevalence and Management of Atrial Thrombi in Patients With Atrial Fibrillation Before Pulmonary Vein Isolation

OBJECTIVES

This study aimed to investigate the prevalence and management of left atrial (LA) thrombi detected by transesophageal echocardiography (TEE) in patients with atrial fibrillation undergoing pulmonary vein isolation (PVI).

BACKGROUND

Little data are available on LA thrombi before PVI.

METHODS

All patients scheduled for PVI between April 2010 and April 2018 undergoing pre-procedural TEE were analyzed. Management of LA thrombus was at the discretion of the treating physician.

RESULTS

In this study, 1,753 pre-procedural TEE from 1,358 patients (mean age 61 ± 10 years, 28% female) were included. Anticoagulation was used in 86% of all TEE (51% with direct oral anticoagulants [DOAC], 35% with vitamin K antagonists [VKA]). Thrombi were found in 11 TEE (0.6%), all in the LA appendage. Of the 11 patients with a thrombus, 5 (46%) had paroxysmal atrial fibrillation, 2 (18%) had a CHA₂DS₂-VASc (Congestive Heart Failure, Hypertension, Age ≥75 Years, Diabetes Mellitus, Prior Stroke or Transient Ischemic Attack or Thromboembolism, Vascular Disease, Age 65 to 74 Years, Sex) score of 1, and 5 (46%) were in sinus rhythm at the time of TEE. Of the 8 patients (72%) on anticoagulation therapy, 5 were treated with DOAC and 3 with VKA. Starting anticoagulation (n = 3), switching to VKA with a target international normalized ratio of 2.5 to 3 (n = 3), or switching to a DOAC (n = 1) or a different DOAC (n = 4) resulted in thrombus resolution in 9 of 11 patients (82%).

CONCLUSIONS

In patients with atrial fibrillation scheduled for PVI, LA thrombi are rare and present in <1%. Thrombi were found in patients on VKA and DOAC, in low-risk patients, and despite sinus rhythm. Thrombus resolution was achieved in the majority of patients by changing the anticoagulation regimen.

The Medtronic Sprint Fidelis® lead history revisited-Extended follow-up of passive leads

BACKGROUND

Due to high failure rates, Medtronic withdrew the Sprint Fidelis lead (SFL) from the market. Passive fixation lead models exhibited better survival than active models, but most studies have limited follow-up. Aim of this study was to give insights into passive lead survival with a follow-up of 10 years.

METHODS

In two large Swiss centers, patients with passive SFLs were identified and data from routine implantable cardioverter defibrillator (ICD) follow-ups were collected. Patients were censored at time of death, last device interrogation (if lost to follow-up), time of lead revision (in non-SFL-related problems), or at database closure (31th December 2017). We defined lead failure as any of the following: lead fracture with inappropriate discharge; sudden increase in low-voltage impedance to >1500 or high-voltage impedance to >100 Ω; >300 nonphysiological short VV-intervals.

RESULTS

We identified 145 patients. Age at implant was 60 ± 12 years with a median follow-up of 10.2 (interquartile range [IQR]: 5.0-11.2) years. Thirty-five percent of patients died after 5.4 ± 2.7 years. A total of 19 leads (13%) failed after 6.7 ± 3.2 years (range: 1.2-12.0). Overt malfunction with shocks existed in four patients (3%). Cumulative lead survival was 93.1% at 6, 88.2% at 8, 83.8% at 10, and 77.6% at 11 years, respectively, with 35% of implanted leads under monitoring at 10 years. Lead survival fits best a Weibull distribution with accelerating failure rates (k = 1.95, 95% CI 1.32-2.87, P < 0.001).

CONCLUSIONS

During very long-term follow-up, failure rate of the passive SFL shows an increase resulting in an impaired lead survival of 84% at 10 years.

Arrhythmic episodes in patients implanted with a cardioverter-defibrillator - results from the Prospective Study on Predictive Quality with Preferencing PainFree ATP therapies (4P)

Background

Little is known about the ICD performance using enhanced detection algorithms in unselected, non-trial patients. Performance of recent generation ICD equipped with SmartShock™ technology (SST) for detection and conversion of ventricular tachyarrhythmias (VTA) was investigated.

Methods

4P was a prospective, multicenter, observational study conducted in 10 Swiss implanting centers. Patients with a Class I indication according to international guidelines were included and received an ICD with SST. ICD discrimination capability was assessed by evaluating SST performance; therapy efficacy was assessed by rate of VTA conversions by ATP and by rescue shocks.

Results

Overall, 196 patients were included in the analysis with a mean duration of follow-up of 27.7 months (452 patient-years of observation). Patient-specific rather than recommended programming was preferred. Device-detected episodes were frequent (5147 episodes in 146 patients, 74.5%). In 44 patients (22.4%), 1274 episodes were categorized as VTA; only 215 episodes were symptomatic. ATP was the first-line therapy and highly effective (99.9% success rate at the episode level, 100.0% at the patient level). Rescue shocks were rare (66 episodes in 28 patients); 7 shocks in 5 patients (2.6%) were inappropriate. Death and hospitalization rates were low.

Conclusions

In a cohort of non-trial, unselected ICD patients, VTA episodes were frequent. The 4P results confirm the robustness of VTA detection by SST and the effectiveness of ATP treatment, hence limiting overall ICD shock burden.

High-sensitivity cardiac Troponin T delta concentration after repeat pulmonary vein isolation

Introduction

Difference between high-sensitivity cardiac troponin T concentrations (hs-cTnT) before and after ablation procedure (delta concentration) reflects the amount of myocardial injury. The aim of the study was to investigate hs-cTnT prognostic power for predicting atrial fibrillation (AF) recurrence after repeat pulmonary vein isolation (PVI) procedure.

Materials and methods

Consecutive patients with paroxysmal AF undergoing repeat PVI using a focal radiofrequency catheter were included in the study. Hs-cTnT was measured before and 18-24 hours after the procedure. Standardized 3, 6 and 12-month follow-up was performed. Cox-regression analysis was used to identify predictors of AF recurrence.

Results

A total of 105 patients undergoing repeat PVI were analysed (24% female, median age 61 years). Median (interquartile range) hs-cTnT delta after repeat PVI was 283 (127 - 489) ng/L. After a median follow-up of 12 months, AF recurred in 24 (23%) patients. A weak linear relationship between the total radiofrequency energy delivery time and delta hs-cTnT was observed (Pearson R² = 0.31, P = 0.030). Delta Hs-cTnT was not identified as a significant long-term predictor of AF recurrence after repeated PVI (P = 0.920).

Conclusion

This was the first study evaluating the prognostic power of delta hs-cTnT in predicting AF recurrence after repeat PVI. Delta hs-cTnT does not predict AF recurrence after repeat PVI procedures. Systematic measurement of hs-cTnT after repeat PVI does not add information relevant to outcome.

High-sensitive cardiac troponin T as a predictor of efficacy and safety after pulmonary vein isolation using focal radiofrequency, multielectrode radiofrequency and cryoballoon ablation catheter

Introduction

Myocardial injury markers such as high-sensitive cardiac troponin T (hs-cTnT) and creatine kinase MB (CK-MB) reflects the amount of myocardial injury with ablation. The aim of the study was to identify the value of myocardial injury markers to predict outcomes after pulmonary vein isolation (PVI) using three different ablation technologies.

Methods

Consecutive patients undergoing PVI using a standard 3.5 mm irrigated-tip radiofrequency catheter (RF-group), an irrigated multielectrode radiofrequency catheter (IMEA-group) and a second-generation cryoballoon (CB-group) were analysed. Blood samples to measure injury markers were taken before and 18–24 hours after the ablation. Procedural complications were collected and standardised follow-up was performed. Logistic regression was used to identify predictors of recurrence and complications.

Results

96 patients (RF group: n=40, IMEA-group: n=17, CB-group: n=39) undergoing PVI only were analysed (82% male, age 59±10 years). After a follow-up of 12 months, atrial fibrillation (AF) recurred in 45% in the RF-group, 29% in the IMEA-group and 36% in the CB-group (p=0.492). Symptomatic pericarditis was observed in 20% of patients in the RF-group, 15% in the IMEA-group and 5% in the CB-group (p=0.131). None of the injury markers was predictive of AF recurrence or PV reconnection after a single procedure. However, hs-cTnT was identified as a predictor of symptomatic pericarditis (OR: 1.003 [1.001 to 1.005], p=0.015).

Conclusion

Hs-cTnT and CK-MB were significantly elevated after PVI, irrespective of the ablation technology used. None of the myocardial injury markers were predictive for AF recurrence or PV reconnection, but hs-cTnT release predicts the occurrence of symptomatic pericarditis after PVI.

Predicting defibrillator benefit in patients with cardiac resynchronization therapy: A competing risk study

BACKGROUND

Cardiac resynchronization therapy (CRT) reduces morbidity and mortality in selected heart failure patients, but decision-making regarding selection of CRT-defibrillator or CRT-pacemaker is an ongoing debate.

OBJECTIVE

The purpose of this study was to construct predictive models and scoring systems for implantable cardioverter-defibrillator (ICD) therapy and death without ICD therapy (prior death).

METHODS

We pooled 2 prospective cohorts of CRT-D patients with primary prevention indication and used Fine and Gray models to develop independent prognostic models for time to first ICD therapy (event of interest) or death without prior ICD therapy (competing event). We defined CRT-D benefit as a high probability of ICD therapy combined with moderate/low probability of prior death.

RESULTS

Seven hundred twenty patients were included. Median follow-up was 7.2 years, and 247 patients (34%) died. Cumulative incidence of ICD therapy/prior death at 5 years was 24%/17%. In multivariable models, higher New York Heart Association classes, diuretic use, and ischemic cardiomyopathy were predictors of ICD therapy (hazard ratio 1.89 [1.30-2.75], 1.91 [1.12-3.24], and 1.40[1.02-1.92], respectively) but not of prior death. Males with comorbidities (cancer, renal failure, peripheral artery disease, body mass index >30) or systolic blood pressure ≤100 were at higher risk for prior death. Higher age was associated with lower risk of ICD therapy but higher risk of prior death. One-quarter of patients had low predicted benefit from CRT-D implantation using a scoring system for the dual prediction of appropriate ICD therapy and death without appropriate ICD-therapy.

CONCLUSION

Different factors predict ICD therapy or prior death in CRT-D patients using competing risk models. Scoring allows identifying patients with predicted low benefit of CRT-D (low chance of ICD therapy, high chance of prior death).

Predictors for early mortality and arrhythmic events in patients with cardiac resynchronization therapy with defibrillator: A two center cohort study

BACKGROUND

Guidelines of heart failure therapy include cardiac resynchronization as standard of care in patients with severely depressed left ventricular function and wide QRS complex. It has been shown that patients benefit regarding mortality and morbidity. However, early mortality precludes longterm benefits from the device. The aim of the study was to identify predictors for early occurrence of both death and first-ever implantable cardioverter-defibrillator (ICD) therapy using a large combined database of patients with cardiac resynchronization therapy with defibrillator (CRT-D).

METHODS

From two registries (tertiary care centers) 904 patients were identified, no single patient was excluded. Early death was defined as death occurring within the 3 years after implantation whereas early ICD therapy as such occurring within the first year. 33 baseline parameters were compared using uni- and multivariate analysis with the Cox model and binary logistic regression.

RESULTS

The population was predominantly male (77%), with mean age of 63 ± 11 years and primary prevention indication in 80%. Mean follow-up was 55 ± 38 months. 256 (28%) patients had ICD therapies whereof the first-ever event occurred early in 52%. 270 (30%) patients died after 41 ± ± 31 months, mostly from advancing heart failure (41%), 141 (52%) patients of them early. Independent predictors for early ICD therapy were secondary prevention and renal failure. Independent predictors for early mortality were a history of percutaneous coronary intervention and of peripheral vascular disease.

CONCLUSIONS

Predictors for early mortality after CRT-D implantation were a history of percutaneous coronary intervention and peripheral vascular disease, present in only a minority of patients, thus limiting their use in clinical practice.

Fast-track versus long-term hospitalizations for patients with non-disabling acute ischaemic stroke

BACKGROUND AND PURPOSE

The aim was to assess the feasibility and safety of fast-track hospitalizations in a selected cohort of patients with stroke.

METHODS

Patients hospitalized at the Stroke Center of the University Hospital Basel, Switzerland, with an acute ischaemic stroke confirmed on magnetic resonance diffusion-weighted imaging were included. Neurological deficits of the included patients were non-disabling, i.e. not interfering with activities of daily living and compatible with a direct discharge home. Patients with premorbid disability were excluded. All patients were admitted to the Stroke Center for ≥24 h. Two study groups were compared - fast-track hospitalizations (≤72 h) and long-term hospitalizations (>72 h). The primary end-point was a composite of any unplanned rehospitalization for any reason within 3 months since hospital discharge and a modified Rankin Scale 3-6 at 3 months. Adjustment for confounders was done using the inverse probability of treatment weights (IPTW).

RESULTS

Amongst the 521 patients who met the inclusion criteria, fast-track hospitalizations were performed in 79 patients (15%). In the fast-track group, seven patients (8.9%) met the primary end-point, compared to 37 (8.4%) in the long-term group [odds ratio (OR) 1.06, 95% confidence interval (CI) 0.42-2.34, P = 0.88]. After weighting for IPTW, the odds of the primary end-point remained similar between the two arms (OR_IPTW 1.27, 95% CI 0.51-3.16, P = 0.61). The costs of fast-track hospitalizations were lower, on average, by $4994.

CONCLUSIONS

Fast-track hospitalizations including a full workup proved to be feasible, showed no increased risk and were less expensive than long-term hospitalizations.

Reliability of luminal oesophageal temperature monitoring during radiofrequency ablation of atrial fibrillation: insights from probe visualization and oesophageal reconstruction using magnetic resonance imaging

Aims

A current concept to prevent atrio-oesophageal fistula during radiofrequency (RF) catheter ablation of atrial fibrillation is to monitor luminal oesophageal temperature (LET). The objective of this study was to describe the temporal course of LET and to assess the reliability of monitoring the maximal LET during pulmonary vein isolation (PVI) using irrigated multi-electrode (IMEA, nMARQTM) and focal ablation catheters.

Methods and results

We studied 40 patients with LET monitoring during PVI (20 patients using the IMEA and 20 patients using the focal catheter). A linear probe was used and visualized in the 3D mapping system. Left atrial and oesophageal reconstructions from delayed enhanced magnetic resonance imaging were integrated. Analysing 745 temperature profiles, LET >38°C was observed in 48 of 296 (17%) and 44 of 449 (10%) ablations for the IMEA and the focal catheter, respectively (P = 0.012). Temporal latency after interruption of RF energy delivery was observed for both catheters. Time until LET baseline temperature was restored after an increase of >1°C was 100 and 86 s for the IMEA and the focal catheter, respectively (P = 0.183). Imprecise representation of the maximal LET was observed in 24 (60%) and 28 patients (70%) for the left and right PVs, respectively.

Conclusion

Due to the unknown exact lateral position of the LET probe within the oesophagus, the measured temperature does not necessarily reflect the maximal LET. The absence of LET increase does not rule out significant temperature increase within the oesophagus. Consequently, the temperature information of the linear multipolar probe should be used with caution.

Reassessment of cardiovascular parameters and comorbidities in implantable cardioverter-defibrillator patients at the time of first replacement

BACKGROUND

Guidelines provide extensive recommendations regarding implantable cardioverter-defibrillator (ICD) implantation. However, ICD replacement at the time of battery depletion is rarely studied.

HYPOTHESIS

Our objectives were to identify patients at high-risk of death after ICD replacement, with a reassessment of changes in risk factors and comorbidities at the time of replacement, and to determine predictors for subsequent mortality.

METHODS

Patients undergoing ICD replacement for regular battery depletion were selected from a prospective single-center ICD registry. Both at implant and replacement, 3 demographic parameters, 9 cardiovascular parameters, 5 comorbidities, and 4 laboratory parameters were collected. Cox proportional hazard analyses were used.

RESULTS

We included 308 patients who were predominantly male (86%) with a median age at ICD replacement of 66 years. Replacement was performed 65 months (interquartile range, 52-91) after implantation. Median follow-up after replacement was 41 months, during which 82 patients (27%) died. Multivariable analysis revealed 4 independent predictors of mortality after ICD replacement: age/year (hazard ratio [HR]: 1.05, 95% confidence interval [CI]: 1.03-1.08, P = 0.01), worsening heart failure by 1 class (HR: 1.53, 95% CI: 1.15-2.03, P = 0.003), presence of left bundle branch block (HR: 1.98, 95% CI: 1.22-3.23, P = 0.006), and ICD therapy prior to replacement (HR: 2.22, 95% CI: 1.37-3.58, P = 0.001). Incorporated into a dichotomous score, they strongly correlated with mortality at 5 years after replacement (5% with 0 parameters, 15% with 1 parameter, and 30%-55% with >2 parameters).

CONCLUSIONS

Focused reassessment of selected patient characteristics at the time of ICD replacement correlates with subsequent mortality and can impact decision making at this point in time.

First clinical experience of a dedicated irrigated-tip radiofrequency ablation catheter for the ablation of cavotricuspid isthmus-dependent atrial flutter

BACKGROUND

Different types of irrigated-tip ablation catheters are available for ablation of atrial flutter (AFL). The aim of this study was to compare an established with a novel dedicated Gold irrigated-tip catheter for ablation of AFL.

METHODS AND RESULTS

We compared consecutive patients undergoing ablation of AFL using a standard 3.5 mm irrigated-tip platinum-iridium (Pt-Ir) catheter (Thermocool, TC-group) and a 3.5 mm irrigated gold-tip catheter (Gold-group) specifically designed for cavotricuspid isthmus ablation (CTI). The primary endpoint was acute efficacy (net RF time) to achieve block across the CTI. Secondary endpoints included procedure time, fluoroscopy duration, complications, and recurrence of AFL.153 patients (age 68 ± 11 years, 74% male) were included. Net RF time to achieve CTI block was not different between the TC-group (793 ± 503 s) and the Gold-group (706 ± 422 s; p = 0.406). Total procedure time was not significantly different between the TC-group (70 ± 26 min) and the Gold-group (70 ± 27 min; p = 0.769). A significant difference between the groups was identified for the fluoroscopy duration (TC-group: 934 ± 537 s, Gold-group: 596 ± 362 s, p < 0.001). There were no major complications observed in the groups. Recurrence of AFL occurred in 3 of 66 (5%) in the TC-group and in 2 of 87 (2%) in the Gold-group (p = 0.652).

CONCLUSIONS

In conclusion, acute and chronic efficacy of the irrigated Pt-Ir and gold-tip catheters were comparable. However, the dedicated catheter design was associated with decreased fluoroscopy duration.

Case report: electrical storm during induced hypothermia in a patient with early repolarization

Background

Population based studies showed an association of early repolarization in the electrocardiogram (ECG) and a higher rate of sudden cardiac death presumably due to ventricular fibrillation. The triggers for ventricular fibrillation in patients with early repolarization are not fully understood.

Case presentation

We describe the case of a young patient with a survived ventricular fibrillation arrest while asleep followed by multiple episodes of recurrent ventricular fibrillation. The admission ECG showed an early repolarization pattern with substantial J-point elevation in most of the ECG-leads. After initiation of a hypothermia protocol, the patient developed an electrical storm with multiple ventricular fibrillation episodes requiring multiple cardioversions. Intravenous isoproterenol infusion successfully suppressed the malignant arrhythmia.

Conclusion

Hypothermia appears proarrhythmic in patients with early repolarization and may trigger ventricular fibrillation. This knowledge is particularly important when initiating temperature management protocols in patients after a survived cardiac arrest. During the acute phase of an early repolarization associated electrical storm, isoproterenol is the most effective treatment suppressing the ventricular fibrillation-inducing premature ventricular complexes at higher heart rates.

Advanced ECG in 2016: is there more than just a tracing?

The 12-lead electrocardiogram (ECG) is the most frequently used technology in clinical cardiology. It is critical for evidence-based management of patients with most cardiovascular conditions, including patients with acute myocardial infarction, suspected chronic cardiac ischaemia, cardiac arrhythmias, heart failure and implantable cardiac devices. In contrast to many other techniques in cardiology, the ECG is simple, small, mobile, universally available and cheap, and therefore particularly attractive. Standard ECG interpretation mainly relies on direct visual assessment. The progress in biomedical computing and signal processing, and the available computational power offer fascinating new options for ECG analysis relevant to all fields of cardiology. Several digital ECG markers and advanced ECG technologies have shown promise in preliminary studies. This article reviews promising novel surface ECG technologies in three different fields. (1) For the detection of myocardial ischaemia and infarction, QRS morphology feature analysis, the analysis of high frequency QRS components (HF-QRS) and methods using vectorcardiography as well as ECG imaging are discussed. (2) For the identification and management of patients with cardiac arrhythmias, methods of advanced P-wave analysis are discussed and the concept of ECG imaging for noninvasive localisation of cardiac arrhythmias is presented. (3) For risk stratification of sudden cardiac death and the selection of patients for medical device therapy, several novel markers including an automated QRS-score for scar quantification, the QRS-T angle or the T-wave peak-to-end-interval are discussed. Despite the existing preliminary data, none of the advanced ECG markers and technologies has yet accomplished the transition into clinical practice. Further refinement of these technologies and broader validation in large unselected patient cohorts are the critical next step needed to facilitate translation of advanced ECG technologies into clinical cardiology.

Persistent improvement of ejection fraction in patients with a cardiac resynchronisation therapy defibrillator correlates with fewer appropriate ICD interventions and lower mortality

QUESTION UNDER STUDY

Cardiac resynchronisation therapy with defibrillator back-up (CRT-D) is a well-established treatment option for selected heart failure patients. Left ventricular ejection fraction (LVEF), an important risk determinant of life-threatening arrhythmias, can substantially ameliorate with CRT. Our hypothesis was that patients with LVEF improvement to >40% have a lower arrhythmic risk and fewer appropriate defibrillator therapies beyond year one.

METHODS

In this retrospective analysis, all 175 patients with CRT-D implanted from February 2000 to June 2011 and follow-up of >2 years were identified. Every available echocardiography recording was collected. LVEF measurements were grouped to baseline and yearly intervals (±6 months). All appropriate defibrillator therapies were considered events.

RESULTS

Age at implant was 65 ± 10 years, 86% were male, and 45% patients had ischemic cardiomyopathy. Follow-up was 5.5 ± 2.6 years. LVEF at implant was 25 ± 6%, increased to 34 ± 12% after one year and remained stable thereafter. 39% (69) of patients experienced a sustained increase of LVEF to ≥40%, 14% of them had tachyarrhythmic events (versus 42.5% in those without such increase). Independent predictors for increase were higher baseline LVEF (HR 1.08 (95%-CI 1.04-1.28) per 1% increase) and lack of amiodarone (HR 0.37, 95%-CI 0.16-0.84). With cut-off values of >40%, >45% and >50%, the study hypothesis was refuted in 7%, 2.5% and 5%, respectively. Cumulative 5-year survival was 95% in improvers versus 73% in non-improvers (p <0.001).

CONCLUSION

After CRT-D implantation, mean LVEF increased to >40% in 1/3 of patients. These patients experienced significantly fewer arrhythmias during long-term follow-up when compared to patients with persisting LVEF <40%.