Cardioversion strategy impacts rate control during recurrences in patients with paroxysmal atrial fibrillation: A subanalysis of the RACE 7 ACWAS trial

BACKGROUND

In the Rate Control versus Electrical Cardioversion Trial 7-Acute Cardioversion versus Wait and See, patients with recent-onset atrial fibrillation (AF) were randomized to either early or delayed cardioversion.

AIM

This prespecified sub-analysis aimed to evaluate heart rate during AF recurrences after an emergency department (ED) visit identified by an electrocardiogram (ECG)-based handheld device.

METHODS

After the ED visit, included patients (n = 437) were asked to use an ECG-based handheld device to monitor for recurrences during the 4-week follow-up period. 335 patients used the handheld device and were included in this analysis. Recordings from the device were collected and assessed for heart rhythm and rate. Optimal rate control was defined as a target resting heart rate of <110 beats per minute (bpm).

RESULTS

In 99 patients (29.6%, mean age 67 ± 10 years, 39.4% female, median 6 [3-12] AF recordings) a total of 314 AF recurrences (median 2 [1-3] per patient) were identified during follow-up. The average median resting heart rate at recurrence was 100 ± 21 bpm in the delayed vs 112 ± 25 bpm in the early cardioversion group (p = .011). Optimal rate control was seen in 68.4% [21.3%-100%] and 33.3% [0%-77.5%] of recordings (p = .01), respectively. Randomization group [coefficient -12.09 (-20.55 to -3.63, p = .006) for delayed vs. early cardioversion] and heart rate on index ECG [coefficient 0.46 (0.29-0.63, p < .001) per bpm increase] were identified on multivariable analysis as factors associated with lower median heart rate during AF recurrences.

CONCLUSION

A delayed cardioversion strategy translated into a favorable heart rate profile during AF recurrences.

High-density mapping for ablation of atypical atrial flutters - procedural characteristics related to outcome

BACKGROUND

High-density (HD) mapping is increasingly used to characterize arrhythmic substrate for ablation of atypical atrial flutters (AAFl). However, results on clinical outcomes and factors that are associated with arrhythmia recurrence are scarce.

METHODS

Single-center, prospective, observational cohort study that enrolled patients with catheter ablation for AAFl using a HD mapping system and a grid-shaped mapping catheter. Procedural characteristics, rates of atrial flutter recurrence, and factors that were associated with atrial flutter recurrence were evaluated.

RESULTS

Sixty-one patients with a total of 94 AAFl were included in the cohort. HD mapping was used to successfully identify the flutter circuit of 80/94 AAFl. The circuit was not identified for 14/94 AAFl in 11 patients. Critical isthmuses were identified and ablated in 29 patients (48%). Acute procedural success was achieved in 52 patients (85%), and 37 patients (61%) remained free from atrial flutter recurrence during a follow up of 1.3 [1.0-2.1] years. Atrial flutter recurrence was univariably associated with presence of a non-identified flutter circuit (HR:2.6 95% CI [1.1-6.3], p = .04) and critical isthmus-targeted ablation (HR:0.4 [0.15-0.90], p = .03). In multivariable regression analyses, critical isthmus ablation remained significant (HR:0.4 [0.16-0.97], p = .04), whereas presence of a non-identified flutter did not (HR:2.4 [0.96-5.8], p = .06).

CONCLUSION

HD mapping was successfully used to identify the majority of AAFl circuits. Ablation resulted in freedom from atrial flutter recurrence in 61% of the cohort. Successful identification of all flutter circuits and critical isthmuses appears to be beneficial for long-term outcomes.

Dielectric response as a novel marker for ablation lesion quality: Relation to conventional ablation parameters

Background

The tissue response viewer (TRV) is a novel marker for ablation lesion quality that aims to classify lesions into transmural or nontransmural lesions (high or low dielectric response, HDR or LDR) using dielectric-based tissue assessment. The objective of this study was to gain insight in the TRV by relating its outcomes to conventional ablation parameters.

Methods

Patients that had repeat ablation for atrial fibrillation with a dielectric imaging-based mapping system were enrolled. All ablation data were downloaded from the mapping system and analyzed to explore associations between TRV outcomes and other ablation parameters.

Results

The cohort included 24 patients, in which 58 pulmonary veins and 8 superior vena cavas were targeted. A total of 388 energy applications were applied, resulting in 639 ablation points. The system classified 36% of ablation points as HDR and 44% as LDR. The system did not provide a dielectric response in 20%. The system's ability to provide a dielectric response was related to longer ablation duration and absence of dragging ablation. HDR (versus LDR) was multivariably associated with longer energy applications, higher mean ablation power, and lower wall thickness. Greater impedance drop was univariably associated with HDR.

Conclusion

Outcomes of the TRV are associated with conventional ablation parameters (e.g., duration and power) but also local wall thickness. Catheter stability seems important for successful lesion assessment with the TRV. Further reduction of missing outcomes and validation of the tool are warranted before widespread use.

Five-year safety and efficacy of leadless pacemakers in a Dutch cohort

BACKGROUND

Adequate real-world safety and efficacy of leadless pacemakers (LPs) has been demonstrated up to three years after implantation. Longer-term data is warranted to assess the net clinical benefit of leadless pacing.

OBJECTIVE

To evaluate the long-term safety and efficacy of LP therapy in a real-world cohort.

METHODS

In this retrospective cohort study, all consecutive patients were included with a first LP implantation from December 21, 2012 to December 13, 2016 in six Dutch high-volume centers. The primary safety endpoint was the rate of major procedure- or device-related complications (i.e., requiring surgery) at five-year follow-up. Analyses were performed with and without Nanostim battery advisory-related complications. The primary efficacy endpoint was the percentage of patients with a pacing capture threshold of ≤2.0V at implantation and without ≥1.5V increase at the last follow-up visit.

RESULTS

179 patients were included (mean age 79±9 years), 93 (52%) with a Nanostim and 86 (48%) with a Micra VR LP. Mean follow-up duration was 44±26 months. Forty-one major complications occurred, of which seven not advisory-related. The five-year major complication rate was 4% without advisory-related complications and 27% including advisory-related complications. Not advisory-related major complications occurred median 10 days (range 0-88 days) post-implantation. The pacing capture threshold was low in 163/167 (98%) and stable in 157/160 (98%).

CONCLUSION

The long-term major complication rate without advisory-related complications was low with LPs. No complications occurred after the acute phase and no infections occurred, which may be a specific benefit of LPs. The performance was adequate with a stable pacing capture threshold.

Long-term success of a multi-electrode substrate mapping and ablation strategy versus a classic single tip mapping and ablation strategy for ventricular tachycardia ablation in patients with ischemic cardiomyopathy

INTRODUCTION

Over the past years, mapping and ablation techniques for the treatment of ventricular tachycardia (VT) have evolved rapidly. High Density (HD) substrate mapping is now routine and pre-procedural imaging is increasingly used. The additional value of these techniques for long-term VT-free survival is not clear.

METHODS

We compared baseline and procedural characteristics, procedural success, safety and outcome of mapping and ablation of ventricular tachycardia in patients with ischemic heart disease between two groups. (1) Low Density (LD) group: VT mapping and ablation with a 4 mm single tip catheter (2) HD group: HD substrate mapping with the Pentaray (Biosense Webster, USA) or HD Grid (Abbott, USA) catheter and ablation with a 4 mm single tip catheter.

RESULTS

VT ablation was performed in 133 patients (71 patients in LD group and 62 patients in HD group). The median follow-up was 5.0 years in LD group and 2.0 years in HD group. One-, two-, and five-year VT recurrence rates were 47%, 56%, and 65% in the LD group versus 39%, 50%, and 55% in the HD group (log-rank test for VT recurrence p = .70). One-, two-, and five-year ICD shock recurrence rates were 14%, 18%, and 24% in the LD group versus 8%, 15%, and 19% in the HD group (log-rank test for ICD-shock p = .79). All-cause mortality, cardiac (non-arrhythmic), and arrhythmic death, were similar in both groups. Severe procedural complications (tamponade, stroke, or procedural death) occurred in four patients (5%, 1 vascular, 3 tamponade) in the LD group versus two patients (3%, both tamponade) in the HD group (NS). In univariate and multivariable analysis, only a higher LVEF was significantly associated with VT-free survival. HD mapping was not significantly associated with VT-free survival. Anterior infarct location and age were significantly associated with ICD recurrent shock in both univariate and multivariable analyses.

CONCLUSIONS

In patients with ischemic cardiomyopathy, a HD substrate mapping, and ablation strategy did not lead to higher VT-free survival and shock-free survival compared to a single tip mapping and ablation strategy. In this study, only LVF is an independent predictor for VT recurrence. Anterior infarct location and age predict recurrent ICD shocks.

Mobile health adherence for the detection of recurrent recent-onset atrial fibrillation

OBJECTIVE

The Rate Control versus Electrical Cardioversion Trial 7-Acute Cardioversion versus Wait and See trial compared early to delayed cardioversion for patients with recent-onset symptomatic atrial fibrillation (AF). This study aims to evaluate the adherence to a 4-week mobile health (mHealth) prescription to detect AF recurrences after an emergency department visit.

METHODS

After the emergency department visit, the 437 included patients, irrespective of randomisation arm (early or delayed cardioversion), were asked to record heart rate and rhythm for 1 min three times daily and in case of symptoms by an electrocardiography-based handheld device for 4 weeks (if available). Adherence was appraised as number of performed measurements per number of recordings asked from the patient and was evaluated for longitudinal adherence consistency. All patients who used the handheld device were included in this subanalysis.

RESULTS

335 patients (58% males; median age 67 (IQR 11) years) were included. The median overall adherence of all patients was 83.3% (IQR 29.9%). The median number of monitoring days was 27 out of 27 (IQR 5), whereas the median number of full monitoring days was 16 out of 27 (IQR 14). Higher age and a previous paroxysm of AF were identified as multivariable adjusted factors associated with adherence.

CONCLUSIONS

In this randomised trial, a 4-week mHealth prescription to monitor for AF recurrences after an emergency department visit for recent-onset AF was feasible with 85.7% of patients consistently using the device with at least one measurement per day. Older patients were more adherent.

TRIAL REGISTRATION NUMBER

NCT02248753.

Long-term monitoring of arrhythmias with cardiovascular implantable electronic devices in patients with cardiac sarcoidosis

BACKGROUND

Risk stratification for sudden cardiac death (SCD) in cardiac sarcoidosis (CS) is challenging in patients without overt cardiac symptoms.

OBJECTIVE

The purpose of this study was to determine the incidence of ventricular arrhythmias (VAs) and mortality after long-term monitoring with a cardiovascular implantable electronic device (CIED) in CS patients identified after systematic screening of patients with extracardiac sarcoidosis (ECS).

METHODS

A retrospective study was performed in 547 predominantly Caucasian patients with ECS screened for cardiac involvement. If CS was diagnosed, risk stratification (high vs low risk) for SCD was performed by a multidisciplinary team. The primary endpoint was defined as sustained VA, appropriate implantable cardioverter-defibrillator (ICD) therapy, or cardiac death.

RESULTS

In total, 105 patients were included (mean follow-up 33 ± 16 months). An ICD was implanted in 17 high-risk patients (16.2%), whereas 80 low-risk patients (76.1%) received an implantable loop recorder (ILR). Eight low-risk patients (7.6%) did not receive a device. The primary endpoint occurred in 4.8% (n = 5), with an overall annualized event rate of 1.7%. The annualized event rate was 9.8% in high-risk patients and 0.4% in low-risk patients. Nine low-risk patients received an ICD during follow-up, in 7 patients as a result of the ILR recordings. None of these patients required ICD therapy.

CONCLUSION

In CS patients without overt cardiac symptoms at initial presentation the annualized overall event rate was 1.7%; 10% in high-risk patients, but only 0.4% in low-risk patients. In low-risk patients long-term arrhythmia monitoring with an ILR enabled early detection of clinically important arrhythmias without showing impact on prognosis.

Non-transvenous ICD therapy: current status and beyond

Subcutaneous implantable cardioverter/defibrillators (S-ICDs) have been developed to offer ICD treatment to patients without venous access to the heart and to overcome complications associated with transvenous leads, particularly lead fracture/insulation defects and endocarditis. Several studies and registries have demonstrated the feasibility and safety of S‑ICD in different groups of patients. Further developments in S‑ICD technology involve the combination with devices that can provide anti-bradycardia and anti-tachycardia pacing if needed. The extravascular ICD (EV-ICD) is a new system that similarly offers ICD therapy without a transvenous lead but uses a substernal instead of a subcutaneous lead to facilitate detection of ventricular fibrillation and to provide anti-tachycardia and also temporary anti-bradycardia pacing. The first animal but also clinical data on EV-ICDs have been published. This review discusses the current state, potential advantages and limitations, and future research of both S‑ICD and EV-ICD.

Advanced image-supported lead placement in cardiac resynchronisation therapy: protocol for the multicentre, randomised controlled ADVISE trial and early economic evaluation

INTRODUCTION

Achieving optimal placement of the left ventricular (LV) lead in cardiac resynchronisation therapy (CRT) is a prerequisite in order to achieve maximum clinical benefit, and is likely to help avoid non-response. Pacing outside scar tissue and targeting late activated segments may improve outcome. The present study will be the first randomised controlled trial to compare the efficacy of real-time image-guided LV lead delivery to conventional CRT implantation. In addition, to estimate the cost-effectiveness of targeted lead implantation, an early decision analytic model was developed, and described here.

METHODS AND ANALYSIS

A multicentre, interventional, randomised, controlled trial will be conducted in a total of 130 patients with a class I or IIa indication for CRT implantation. Patients will be stratified to ischaemic heart failure aetiology and 1:1 randomised to either empirical lead placement or live image-guided lead placement. Ultimate lead location and echocardiographic assessment will be performed by core laboratories, blinded to treatment allocation and patient information. Late gadolinium enhancement cardiac magnetic resonance imaging (CMR) and CINE-CMR with feature-tracking postprocessing software will be used to semi-automatically determine myocardial scar and late mechanical activation. The subsequent treatment file with optimal LV-lead positions will be fused with the fluoroscopy, resulting in live target-visualisation during the procedure. The primary endpoint is the difference in percentage of successfully targeted LV-lead location. Secondary endpoints are relative percentage reduction in indexed LV end-systolic volume, a hierarchical clinical endpoint, and quality of life. The early analytic model was developed using a Markov-model, consisting of seven mutually exclusive health states.

ETHICS AND DISSEMINATION

The protocol was approved by the Medical Research Ethics Committee Utrecht (NL73416.041.20). All participants are required to provide written informed consent. Results will be submitted to peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT05053568; Trial NL8666.

Dielectric imaging for electrophysiology procedures: The technology, current state, and future potential

Electroanatomic mapping systems have become an essential tool to guide the identification and ablation of arrhythmic substrate. Recently, a novel guiding system for electrophysiology procedures was introduced that uses dielectric sensing to perform high resolution anatomical imaging. Dielectric imaging systems use electrical fields to differentiate anatomic structures based on their conductivity and permittivity. This technique enables non-fluoroscopic, noncontact mapping of anatomic structures, assessment of pulmonary vein occlusion state during cryoballoon ablation, and has the potential to assess for additional tissue characterization including tissue thickness and tissue type. This article elaborates on the functioning and potential of dielectric imaging systems and provides two cases to illustrate the clinical impact for electrophysiology procedures.

[A poisonous spring smoothie with wild herbs: accidental intoxication with foxglove (Digitalis purpurea)]

BACKGROUND

At a time when self-sufficiency and health are becoming increasingly important in society, the chances of intoxications with wild plants are increasing. Foxglove contains poisonous cardiac glycosides such as digoxin, digitoxin and gitoxin. The levels vary greatly and depend on the season and the location of the plants. The "non-digoxin" cardiac glycosides show a limited cross-reaction with the digoxin assay. This means that a low or therapeutic digoxin level does not rule out a severe foxglove intoxication. Due to the long half-life of the different cardiac glycosides, toxic symptoms can be persistent.

CASE DESCRIPTION

A 43-year-old woman arrived at the Emergency Department with persistent vomiting and specific ECG-abnormalities. The day before, she drunk a smoothie made from wild plants picked in the woods. Patient appeared to have mistaken foxglove for common sorrel.

CONCLUSION

In case of persistent gastrointestinal complaints with specific ECG abnormalities after ingestion of plant material, clinicians should be aware of a foxglove intoxication.

Left atrial catheter ablation in patients with previously implanted left atrial appendage closure devices

AIMS

Left atrial appendage closure (LAAC) is increasingly used as an alternative to oral anticoagulation (OAC) for stroke prevention in atrial fibrillation (AF) patients. Feasibility and safety of left atrial (LA) catheter ablation (CA) in patients with previously implanted LAAC devices have not been well studied. We report on the feasibility, safety, and efficacy of LA CA in the presence of a previously implanted LAAC device.

METHODS AND RESULTS

In this prospective cohort study consecutive patients that underwent LA CA with a previously implanted Watchman device were included. Periprocedural characteristics and long-term clinical follow-up were evaluated. Twenty-three LA CA procedures were performed in 19/162 AF patients with previously implanted Watchman devices [47% male, age 63.9 ± 6.2 years, CHA2DS2-VASc 4.0 (3.0-5.0); HASBLED 3.0 (2.0-4.0); 63% paroxysmal]. Left atrial CA was performed with irrigated radiofrequency (RF; n = 20, 87%) or phased RF (n = 3, 13%) in a mean of 18 months after LAAC implantation (range 4-80 months). Targets of CA consisted of pulmonary vein isolation (n = 19, 83%), superior vena cava isolation (n = 13, 57%), and additional linear lesions (n = 8, 35%). Procedures were carried out under vitamin K antagonist (VKA; n = 6, 26%), non-VKA OAC (NOAC; n = 8, 35%), or single antiplatelet therapy alone (n = 9, 39%). Left atrial CA was successful without any signs of interference from the device. Procedure-related complications were not observed. During a mean follow-up of 28 months, 11 patients (58%) had AF recurrence.

CONCLUSION

Left atrial CA after LAAC appears to be feasible, effective, and safe in this single centre cohort. Previously implanted Watchman device should not be a reason to relinquish CA in symptomatic AF patients, even in patients on single antiplatelet therapy alone.

ICD implantation for secondary prevention in patients with ventricular arrhythmia in the setting of acute cardiac ischemia and a history of myocardial infarction

INTRODUCTION

In patients with a prior myocardial infarction (MI) but preserved left ventricular (LV) function, sustained ventricular arrhythmias (VAs) may arise in the setting of an acute coronary syndrome (ACS). It is unknown whether an implantable cardioverter-defibrillator (ICD) is mandatory in these patients as VA might be triggered by a reversible cause. The purpose of this study is to analyze the benefit of ICD therapy in this patient population.

METHODS

We conducted a retrospective observational study in ICD recipients implanted from 2008 to 2011. The study group consisted of patients with sustained VA in the setting of an ACS, with a history of MI, but with left ventricular ejection fraction (LVEF) greater than 35 (group A). The two control groups consisted of patients admitted with VA with a history of MI, but without ACS at presentation, either with LVEF greater than 35% (group B) or ≤35% (group C). The primary endpoint was the number of patients with appropriate ICD therapy (antitachycardia pacing or shock).

RESULTS

A total of 291 patients were included with a mean follow-up of 5.3 years. Appropriate ICD therapy occurred in 45.6% of the patients in group A vs 51.6% and 60.4% in groups B and C (P = .11). In group A, 31.1% received an appropriate ICD shock vs 34.7% and 44.3% in control groups B and C (P = .12).

CONCLUSION

On the basis of these data, ICD implantation seems warranted in patients with history of MI presenting with VA in the setting of an ACS, despite preserved LV function and adequate revascularization. Further trials, preferably randomizes, should be performed to address these findings.

A combined epicardial implantation and subsequent extraction strategy in pacemaker device infection in pacemaker-dependent patients

INTRODUCTION

Treatment infections is challenging in pacemaker (PM) dependent patients. We proposed a novel implantation strategy for this group of patients.

METHODS

Patients who were PM dependent and were admitted with a PM infection received a combined procedure of left ventricular (LV) epicardial implantation of a PM lead and subsequent extraction of the infected system. No temporary pacing wire was used and the PM generator was placed in the left flank.

RESULTS

Between 2012 and 2015 we treated 16 patients who were PM dependent and with a PM infection. The majority of patients were male (81% [13/16]) and the median age was 71 years (50-91). The cause of infection was valvular endocarditis in 38% (6/16), lead infection in 25% (4/16), and isolated pocket infection in 38% (6/16). All patients underwent epicardial implantation of a LV lead (1084T bipolar lead; St. Jude Medical Myodex, St. Paul, MN, USA) and extraction of the infected device. There was no occurrence of periprocedural mortality and no postprocedural tamponades. There was one complication in the form of a hemorrhage at the infected device extraction site. In the median follow-up period of 17 months there were four of 16 deaths, none of which were attributable to epicardial LV implantation. LV-lead threshold was 1.1V (±0.7V) upon implantation that increased to 1.2V (±0.6V) at 0.4-ms pulse duration. There were no reinfections of the epicardial lead or device.

CONCLUSION

Epicardial left ventricle PM implantation and subsequent extraction of an infected PM in PM-dependent patients is feasible and safe with good long-term outcome.