Sex-specific outcomes after catheter ablation for persistent AF

BACKGROUND

Sex-specific outcomes after catheter ablation (CA) for atrial fibrillation (AF) have reported conflicting findings.

OBJECTIVE

We examined the impact of female sex on outcomes in patients with persistent AF (PsAF) from the Catheter Ablation for Persistent Atrial Fibrillation: A Multicentre Randomized Trial of Pulmonary Vein Isolation vs PVI with Posterior Left Atrial Wall Isolation (CAPLA) randomized trial.

METHODS

A total of 338 patients with PsAF were randomized to pulmonary vein isolation (PVI) or PVI with posterior wall isolation (PWI). The primary outcome was arrhythmia recurrence at 12 months. Clinical and electroanatomical characteristics, arrhythmia recurrence, and quality of life were compared between women and men.

RESULTS

Seventy-nine women (23.4%; PVI 37; PVI + PWI 42) and 259 men (76.6%; PVI 131; PVI + PWI 128) underwent AF ablation. Women were older {median age 70.4 (interquartile range [IQR] 64.8-74.6) years vs 64.0 (IQR 56.7-69.7) years; P < .001} and had more advanced left atrial electroanatomical remodeling. At 12 months, arrhythmia-free survival was lower in women (44.3% vs 56.8% in men; hazard ratio 1.44; 95% confidence interval 1.02-2.04; log-rank, P = .036). PWI did not improve arrhythmia-free survival at 12 months (hazard ratio 1.02; 95% confidence interval 0.74-1.40; log-rank, P = .711). The median AF burden was 0% in both groups (women: IQR 0.0%-2.2% vs men: IQR 0.0%-2.8%; P = .804). Health care utilization was comparable between women (36.7%) and men (30.1%) (P = .241); however, women were more likely to undergo a repeat procedure (17.7% vs 6.9%; P = .007). Women reported more severe baseline anxiety (average Hospital Anxiety and Depression Scale [HADS] anxiety score 7.5 ± 4.9 vs 6.3 ± 4.3 in men; P = .035) and AF-related symptoms (baseline Atrial Fibrillation Effect on Quality-of-Life Questionnaire [AFEQT] score 46.7 ± 20.7 vs 55.9 ± 23.0 in men; P = .002), with comparable improvements in psychological symptoms (change in HADS anxiety score -3.8 ± 4.6 vs -3.0 ± 4.5; P = .152 (change in HADS depression score -2.9 ± 5.0 vs -2.6 ± 4.0; P = .542) and greater improvement in AFEQT score compared with men at 12 months (change in AFEQT score +45.9 ± 23.1 vs +39.2 ± 24.8; P = .048).

CONCLUSION

Women undergoing CA for PsAF report more significant symptoms and poorer quality of life at baseline than men. Despite higher arrhythmia recurrence and repeat procedures in women, the AF burden was comparably low, resulting in significant improvements in quality of life and psychological well-being after CA in both sexes.

Long-Term Outcomes of Resynchronization-Defibrillation for Heart Failure

BACKGROUND

The Resynchronization-Defibrillation for Ambulatory Heart Failure Trial (RAFT) showed a greater benefit with respect to mortality at 5 years among patients who received cardiac-resynchronization therapy (CRT) than among those who received implantable cardioverter-defibrillators (ICDs). However, the effect of CRT on long-term survival is not known.

METHODS

We randomly assigned patients with New York Heart Association (NYHA) class II or III heart failure, a left ventricular ejection fraction of 30% or less, and an intrinsic QRS duration of 120 msec or more (or a paced QRS duration of 200 msec or more) to receive either an ICD alone or a CRT defibrillator (CRT-D). We assessed long-term outcomes among patients at the eight highest-enrolling participating sites. The primary outcome was death from any cause; the secondary outcome was a composite of death from any cause, heart transplantation, or implantation of a ventricular assist device.

RESULTS

The trial enrolled 1798 patients, of whom 1050 were included in the long-term survival trial; the median duration of follow-up for the 1050 patients was 7.7 years (interquartile range, 3.9 to 12.8), and the median duration of follow-up for those who survived was 13.9 years (interquartile range, 12.8 to 15.7). Death occurred in 405 of 530 patients (76.4%) assigned to the ICD group and in 370 of 520 patients (71.2%) assigned to the CRT-D group. The time until death appeared to be longer for those assigned to receive a CRT-D than for those assigned to receive an ICD (acceleration factor, 0.80; 95% confidence interval, 0.69 to 0.92; P = 0.002). A secondary-outcome event occurred in 412 patients (77.7%) in the ICD group and in 392 (75.4%) in the CRT-D group.

CONCLUSIONS

Among patients with a reduced ejection fraction, a widened QRS complex, and NYHA class II or III heart failure, the survival benefit associated with receipt of a CRT-D as compared with ICD appeared to be sustained during a median of nearly 14 years of follow-up. (RAFT ClinicalTrials.gov number, NCT00251251.).

Ventricular Tachycardia and ICD Therapy Burden With Catheter Ablation Versus Escalated Antiarrhythmic Drug Therapy

BACKGROUND

Catheter ablation improves ventricular tachycardia (VT) event-free (time to event) survival in patients with antiarrhythmic drug (AAD)-refractory VT and previous myocardial infarction (MI). The effects of ablation on recurrent VT and implantable cardioverter-defibrillator (ICD) therapy (burden) have yet to be investigated.

OBJECTIVES

This study sought to compare the VT and ICD therapy burden following treatment with either ablation or escalated AAD therapy among patients with VT and previous MI in the VANISH (Ventricular tachycardia AblatioN versus escalated antiarrhythmic drug therapy in ISchemic Heart disease) trial.

METHODS

The VANISH trial randomized patients with previous MI and VT despite initial AAD therapy to either escalated AAD treatment or catheter ablation. VT burden was defined as the total number of VT events treated with ≥1 appropriate ICD therapy. Appropriate ICD therapy burden was defined as the total number of appropriate shocks or antitachycardia pacing therapies (ATPs) delivered. The Anderson-Gill recurrent event model was used to compare burden between the treatment arms.

RESULTS

Of the 259 enrolled patients (median age, 69.8 years; 7.0% women), 132 patients were randomized to ablation and 129 patients were randomized to escalated AAD therapy. Over 23.4 months of follow-up, ablation-treated patients had a 40% lower shock-treated VT event burden and a 39% lower appropriate shock burden compared with patients who received escalated AAD therapy (P <0.05 for all). A reduction in VT burden, ATP-treated VT event burden, and appropriate ATP burden among ablation patients was only demonstrated in the stratum of patients with amiodarone-refractory VT (P <0.05 for all).

CONCLUSIONS

Among patients with AAD-refractory VT and a previous MI, catheter ablation reduced shock-treated VT event burden and appropriate shock burden compared with escalated AAD therapy. There was also lower VT burden, ATP-treated VT event burden, and appropriate ATP burden among ablation-treated patients; however, the effect was limited to patients with amiodarone-refractory VT.

Standard vs Augmented Ablation of Paroxysmal Atrial Fibrillation for Reduction of Atrial Fibrillation Recurrence: The AWARE Randomized Clinical Trial

Importance

Recurrent atrial fibrillation (AF) commonly occurs after catheter ablation and is associated with patient morbidity and health care costs.

Objective

To evaluate the superiority of an augmented double wide-area circumferential ablation (WACA) compared with a standard single WACA in preventing recurrent atrial arrhythmias (AA) (atrial tachycardia, atrial flutter, or atrial fibrillation [AF]) in patients with paroxysmal AF.

Design, Setting, and Participants

This was a pragmatic, multicenter, prospective, randomized, open, blinded end point superiority clinical trial conducted at 10 university-affiliated centers in Canada. The trial enrolled patients 18 years and older with symptomatic paroxysmal AF from March 2015 to May 2017. Analysis took place between January and April 2022. Analyses were intention to treat.

Interventions

Patients were randomized (1:1) to receive radiofrequency catheter ablation for pulmonary vein isolation with either a standard single WACA or an augmented double WACA.

Main Outcomes and Measures

The primary outcome was AA recurrence between 91 and 365 days postablation. Patients underwent 42 days of ambulatory electrocardiography monitoring after ablation. Secondary outcomes included need for repeated catheter ablation and procedural and safety variables.

Results

Of 398 patients, 195 were randomized to the single WACA (control) arm (mean [SD] age, 60.6 [9.3] years; 65 [33.3%] female) and 203 to the double WACA (experimental) arm (mean [SD] age, 61.5 [9.3] years; 66 [32.5%] female). Overall, 52 patients (26.7%) in the single WACA arm and 50 patients (24.6%) in the double WACA arm had recurrent AA at 1 year (relative risk, 0.92; 95% CI, 0.66-1.29; P = .64). Twenty patients (10.3%) in the single WACA arm and 15 patients (7.4%) in the double WACA arm underwent repeated catheter ablation (relative risk, 0.72; 95% CI, 0.38-1.36). Adjudicated serious adverse events occurred in 13 patients (6.7%) in the single WACA arm and 14 patients (6.9%) in the double WACA arm.

Conclusions and Relevance

In this randomized clinical trial of patients with paroxysmal AF, additional ablation by performing a double ablation lesion set did not result in improved freedom from recurrent AA compared with a standard single ablation set.

Trial Registration

ClinicalTrials.gov Identifier: NCT02150902.

Antitachycardia pacing success in implantable cardioverter-defibrillators by patient, device, and programming characteristics

BACKGROUND

Antitachycardia pacing (ATP) is an established implantable cardioverter-defibrillator (ICD) therapy that terminates ventricular tachycardias (VTs) without painful ICD shocks. However, factors influencing ATP success are not well understood.

OBJECTIVE

The purpose of this study was to examine ATP success rates by patient, device, and programming characteristics.

METHODS

This retrospective analysis of the PainFree SmartShock Technology study included spontaneous ATP-treated monomorphic VT episodes. ATP success rates were calculated for various factors. Also, the relationship of ATP programming on shock burden and syncope were investigated.

RESULTS

Of the 2770 enrolled patients (2200 [79%] male; mean age 65 years), 1699 (61%) received an ICD and 1071 (39%) a cardiac resynchronization therapy - defibrillator. ATP had >80% rate of success for terminating VTs overall, with similar rates observed between ICD and cardiac resynchronization therapy - defibrillator devices (82.2% vs 80.3%, respectively; P = .81) as well as between primary and secondary prevention patients with ICDs (77.2% vs 83.9% respectively; P = .25). Arrhythmias with a median cycle length of ≥320 ms had a significantly higher ATP success rate (88.0%; 95% confidence interval 84.8%-90.6%). The cumulative percentage of ATP success increased from 71% at 1 ATP sequence delivered to 87% at ≥8 sequences delivered. Programming more ATP sequences was associated with lower shock burden (P = .0005). There was no evidence that more sequences were associated with higher rates of syncope (P = .16).

CONCLUSION

Delivering more ATP sequences resulted in a higher overall success of terminating VTs, while programming more ATP was associated with decreased shock burden and no evidence of increased syncope or acceleration. This suggests that more ATP sequences should be programmed when possible, but confirmation in prospective studies will be necessary.

First Randomized, Multicenter, Placebo-Controlled Study of Self-Administered Intranasal Etripamil for Acute Conversion of Spontaneous Paroxysmal Supraventricular Tachycardia (NODE-301)

Background:

Pharmacologic termination of paroxysmal supraventricular tachycardia (PSVT) often requires medically supervised intervention. Intranasal etripamil, is an investigational fast-acting, nondihydropyridine, L-type calcium channel blocker, designed for unsupervised self-administration to terminate atrioventricular nodal–dependent PSVT. Phase 2 results showed potential safety and efficacy of etripamil in 104 patients with PSVT.

Methods:

NODE-301, a phase 3, multicenter, double-blind, placebo-controlled study evaluated the efficacy and safety of etripamil nasal spray administered, unsupervised in patients with symptomatic sustained PSVT. After a medically supervised etripamil test dose while in sinus rhythm, patients were randomized 2:1 to receive etripamil 70 mg or placebo. When PSVT symptoms developed, patients applied a cardiac monitor and attempted a vagal maneuver; if symptoms persisted, they self-administered blinded treatment. An independent Adjudication Committee reviewed continuous electrocardiogram recordings. The primary efficacy endpoint was termination of adjudicated PSVT within 5 hours after study drug administration.

Results:

NODE-301 accrued 156 positively adjudicated PSVT events treated with etripamil (n=107) or placebo (n=49). The hazard ratio for the primary endpoint, time-to-conversion to sinus rhythm during the 5-hour observation period, was 1.086 (95% CI, 0.726–1.623; P =0.12). In predefined sensitivity analyses, etripamil effects (compared with placebo) occurred at 3, 5, 10, 20, and 30 minutes ( P <0.05). For example, at 30 minutes, there was a 53.7% of SVT conversion in the treatment arm compared to 34.7% in the placebo arm (hazard ratio, 1.87 [95% CI, 1.09–3.22]; P =0.02). Etripamil was well tolerated; adverse events were mainly related to transient nasal discomfort and congestion (19.6% and 8.0%, respectively, of randomized treatment-emergent adverse events.

Conclusions:

Although the primary 5-hour efficacy endpoint was not met, analyses at earlier time points indicated an etripamil treatment effect in terminating PSVT. Etripamil self-administration during PSVT was safe and well tolerated. These results support continued clinical development of etripamil nasal spray for self-administration during PSVT in a medically unsupervised setting.

REGISTRATION:

URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03464019.

Augmented wide area circumferential catheter ablation for reduction of atrial fibrillation recurrence (AWARE) trial: Design and rationale

BACKGROUND

Recurrence of atrial fibrillation (AF) after a pulmonary vein isolation procedure is often due to electrical reconnection of the pulmonary veins. Repeat ablation procedures may improve freedom from AF but are associated with increased risks and health care costs. A novel ablation strategy in which patients receive "augmented" ablation lesions has the potential to reduce the risk of AF recurrence.

OBJECTIVE

The Augmented Wide Area Circumferential Catheter Ablation for Reduction of Atrial Fibrillation Recurrence (AWARE) Trial was designed to evaluate whether an augmented wide-area circumferential antral (WACA) ablation strategy will result in fewer atrial arrhythmia recurrences in patients with symptomatic paroxysmal AF, compared with a conventional WACA strategy.

METHODS/DESIGN

The AWARE trial was a multicenter, prospective, randomized, open, blinded endpoint trial that has completed recruitment (ClinicalTrials.gov NCT02150902). Patients were randomly assigned (1:1) to either the control arm (single WACAlesion set) or the interventional arm (augmented- double WACA lesion set performed after the initial WACA). The primary outcome was atrial tachyarrhythmia (AA; atrial tachycardia [AT], atrial flutter [AFl] or AF) recurrence between days 91 and 365 post catheter ablation. Patient follow-up included 14-day continuous ambulatory ECG monitoring at 3, 6, and 12 months after catheter ablation. Three questionnaires were administered during the trial- the EuroQuol-5D (EQ-5D) quality of life scale, the Canadian Cardiovascular Society Severity of Atrial Fibrillation scale, and a patient satisfaction scale.

DISCUSSION

The AWARE trial was designed to evaluate whether a novel approach to catheter ablation reduced the risk of AA recurrence in patients with symptomatic paroxysmal AF.

Reduction in shock burden with catheter ablation versus escalated antiarrhythmic drug therapy: Insights from the VANISH trial

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): 1. Canadian Institutes of Health Research (CIHR)

2. Additional financial support from St. Jude Medical and Biosense Webster

Background

Recurrent shocks for ventricular tachycardia (VT) are associated with an increased risk of heart failure and mortality and have a negative influence on quality of life. Catheter ablation has been shown to improve VT event-free survival in patients with antiarrhythmic drug (AAD)-refractory VT and prior myocardial infarction (MI); however, the effects of ablation on shock burden has yet to be investigated.

Purpose

Our primary objectives were to compare the shock-treated VT event burden and appropriate shock burden following randomization to treatment with either catheter ablation or escalated AAD therapy among VT patients with prior MI in the Ventricular tachycardia AblatioN versus escalated antiarrhythmic drug therapy in Ischemic Heart disease (VANISH) randomized trial.

Methods

Recurrent event analyses were performed using the intention-to-treat population of the VANISH trial. Shock-treated VT event burden was defined as the total number of VT events treated with ≥1 appropriate internal or external shocks. Appropriate shock burden was defined as the total number of appropriate internal and external shocks delivered, regardless of the number of VT events. All VT events and implantable cardioverter defibrillator (ICD) therapies were adjudicated by reviewers blinded to the treatment allocation. Three recurrent event models were used to compare the shock burden between treatment arms (Anderson-Gill (AG), Frailty, and Prentice, Williams, and Peterson Total Time (PWP-TT). Each model clustered by patient and accounted for competing risk of death with the Fine and Gray sub-distributions hazards model.

Results

Of the 259 patients enrolled in the VANISH trial [median age 69.8 (IQR 63.0-74.2) years, 7.0% women], 132 patients were randomized to ablation and 129 patients to escalated AAD therapy. Over a median follow-up of 23.4 (IQR 14.7-40.4) months, there were 138 shock-treated VT events [39.07 (95% CI 33.14-46.07) shock-treated VT events per 100 person-years] in the ablation arm and 218 shock-treated VT events [64.60 (95% CI 56.49–73.84) shock-treated VT events per 100 person-years] in the escalated AAD therapy arm (Figure 1). Ablation patients had a 40% lower shock-treated VT event burden (ie. number of shock-treated VT events) compared to patients randomized to escalated AAD therapy [Figure 1; AG HR 0.60 (95% 0.38-0.95)]. Further, there was also a statistically significant reduction in the appropriate shock burden (i.e. number of appropriate shocks) among ablation patients (169 appropriate shocks) compared to escalated AAD therapy patients (266 appropriate shocks) [Figure 1; AG HR 0.61 (95% CI 0.37-0.96)]. All results were consistent between the 3 recurrent event models.

Conclusion

Among patients with AAD-refractory VT and a prior MI, catheter ablation reduced shock-treated VT event burden and appropriate shock burden compared to escalated AAD therapy.

Ventricular tachycardia characteristics and outcomes with catheter ablation vs. antiarrhythmic therapy: insights from the VANISH trial

AIMS

Catheter ablation is superior to escalated antiarrhythmic drugs among patients with ventricular tachycardia (VT) and prior myocardial infarction (MI). However, it is uncertain whether clinical VT characteristics, should influence choice of therapy. The purpose of this study was to evaluate whether presentation with electrical storm and the clinical VT cycle length predicted response to ablation vs. escalated antiarrhythmic therapy.

METHODS AND RESULTS

All patients enrolled in the Ventricular Tachycardia Ablation vs. Escalated Antiarrhythmic Drug Therapy in Ischaemic Heart Disease (VANISH) trial were included. The association between VT cycle length and presentation with electrical storm and the primary outcome of death, subsequent VT storm or appropriate ICD shock was evaluated. Among the study population of 259 patients, escalated antiarrhythmic drug therapy had worse outcomes for those presenting with a VT cycle length >400 ms [<150 b.p.m., 89/259, hazard ratio (HR) 1.7 (1.02-3.13)]. This effect was more pronounced among those taking amiodarone at baseline [HR of 2.22 (1.19-4.16)]. Presentation with VT storm (32/259) did not affect the primary outcome between groups. However, those presenting with VT storm on amiodarone had a trend towards worse outcomes with escalated antiarrhythmic therapy [HR 4.31 (0.55-33.93)].

CONCLUSION

The VT cycle length can influence response to either ablation or escalated drug therapy in patients with VT and prior MI. Those with slow VT had improved outcomes with ablation. Patients presenting with electrical storm demonstrated similar outcomes to the overall trial population, with a trend to benefit of catheter ablation, particularly in those on amiodarone.

Performance evaluation of implantable cardioverter-defibrillators with SmartShock technology in patients with inherited arrhythmogenic diseases

BACKGROUND

Patients with inherited arrhythmogenic diseases (IADs) are often prescribed preventative implantable cardioverter-defibrillators (ICDs) to manage their increased sudden cardiac arrest risk. However, it has been suggested that ICDs in IAD patients may come with additional risk. We aimed to leverage the PainFree SmartShock Technology dataset to compare inappropriate therapies, appropriate therapies, mortality, and complications in patients with and without IAD.

METHODS

This retrospective analysis included extracted, physician-adjudicated, arrhythmic episodes from ICD devices. The incidence of arrhythmic events was estimated with the Kaplan-Meier method using the log-rank test. Cox proportional hazards regression was used to estimate hazard ratios (HRs) with their 95% confidence intervals (CIs).

RESULTS

Of the 1699 ICD patients, 77 patients (4.5%) had IAD. Incidence of inappropriate shock was similar in both patients with (3.2% at 24 months) and without (3.8% at 24 months) IAD (HR: 0.80, CI: 0.19-3.30, p = 0.76). In a multivariable analysis IAD was not significantly associated with reduced mortality (HR: 0.64, CI: 0.08-4.80, p = 0.66). The rates of complications were numerically lower in patients with IAD vs without (8.8% vs 9.6% at 24 months respectively), but not statistically significant (HR: 0.83, CI: 0.20-3.38, p = 0.79).

CONCLUSIONS

IAD patients showed a very low annual rate of inappropriate therapy. This suggests that newer algorithms, such as the SST algorithm, are equally good at identifying and treating life-threatening arrhythmias in patients regardless of whether they have IAD.

Comparative effectiveness of ventricular tachycardia ablation vs. escalated antiarrhythmic drug therapy by location of myocardial infarction: a sub-study of the VANISH trial

AIMS

Complexity of the ventricular tachycardia (VT) substrate and the size and thickness of infarction area border zones differ based on location of myocardial infarctions (MIs). These differences may translate into heterogeneity in the effectiveness of treatments. This study aims to examine the influence of infarct location on the effectiveness of VT ablation in comparison with escalated pharmacological therapy in patients with prior MI and antiarrhythmic drug (AAD)-refractory VT.

METHODS AND RESULTS

VANISH trial participants were categorized based on the presence or absence of an inferior MI scar. Inverse probability of treatment weighted Cox models were calculated for each subgroup. Of 259 randomized patients (median age 69.8 years, 7.0% women), 135 had an inferior MI and 124 had a non-inferior MI. Among patients with an inferior MI, no statistically significant difference in the composite primary outcome of all-cause mortality, appropriate implantable cardioverter-defibrillator (ICD) shock, and VT storm was detected between treatment arms [adjusted hazard ratio (aHR) 0.80, 95% confidence interval (CI) 0.51-1.20]. In contrast, patients with non-inferior MIs had a statistically significant reduction in the incidence of the primary outcome with ablation (aHR 0.48, 95% CI 0.27-0.86). In a sensitivity analysis of anterior MI patients (n = 83), a trend towards a reduction in the primary outcome with ablation was detected (aHR 0.50, 95% CI 0.23-1.09).

CONCLUSION

The effectiveness of VT ablation versus escalated AADs varies based on the location of the MI. Patients with MI scars located only in non-inferior regions of the ventricles derive greater benefit from VT ablation in comparison to escalation of AADs in reducing VT-related events.

2021 Update on Safety of Magnetic Resonance Imaging: Joint Statement From Canadian Cardiovascular Society/Canadian Society for Cardiovascular Magnetic Resonance/Canadian Heart Rhythm Society

Magnetic resonance imaging (MRI) is often considered the gold-standard test for characterizing cardiac as well as noncardiac structure and function. However, many patients with cardiac implantable electronic devices (CIEDs) and/or severe renal dysfunction are unable to undergo this test because of safety concerns. In the past 10 years, newer-generation CIEDs and gadolinium-based contrast agents (GBCAs) as well as coordinated care between imaging and heart rhythm device teams have mitigated risk to patients and improved access to MRI at many hospitals. The purpose of this statement is to review published data on safety of MRI in patients with conditional and nonconditional CIEDs in addition to patient risks from older and newer GBCAs. This statement was developed through multidisciplinary collaboration of pan-Canadian experts after a relevant and independent literature search by the Canadian Agency for Drugs and Technologies in Health. All recommendations align with the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. Key recommendations include: (1) the development of standardized protocols for patients with a CIED undergoing MRI; (2) patients with MRI nonconditional pacemakers and pacemaker dependency should be programmed to asynchronous mode and those with MRI nonconditional transvenous defibrillators should have tachycardia therapies turned off during the scan; and (3) macrocyclic or newer linear GBCAs should be used in preference to older GBCAs because of their better safety profile in patients at higher risk of nephrogenic systemic fibrosis.

Comparative effectiveness of ventricular tachycardia ablation versus escalated antiarrhythmic drug therapy by location of myocardial infarction: A sub-study of the VANISH trial

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): Fonds de recherché du Québec-Santé (FRQS) [post doctoral award for Dr. Samuel)

BACKGROUND

Complexity of ventricular tachycardia (VT) substrate, efficiency of lesion formation, and the size and thickness of infarction area border zones differ based on location of myocardial infarctions (MI). These differences may translate into heterogeneity in risk of events and effectiveness of treatments for VT. Small observational studies suggest that VT from inferior infarctions have higher risk of early recurrence despite smaller infarct areas. However, differential effectiveness of VT treatments based on location of MI not been definitively established.

PURPOSE

The objective of this sub-study of the Ventricular tachycardia AblatioN versus escalated antiarrhythmic drug therapy in ISchemic Heart disease (VANISH) randomized trial was to compare the effectiveness of VT ablation by location of MI in reducing the composite endpoint of all-cause mortality, VT storm, or appropriate ICD therapy when compared to escalated pharmacological therapy in VT patients with a prior MI.

METHODS

VANISH participants were categorized into 3 subgroups based on MI location: 1. Inferior (may also have MI in other locations); 2. Non-inferior (no inferior MI, all patients not in group 1); and 3. Anterior (may also have MI in other locations). Inverse probability of treatment weighting was used to balance baseline characteristics (ie. age, sex, comorbidities, medications, and the location of additional infarctions) between patients randomized to ablation or escalated therapy within each subgroup. Weighted Cox proportional hazards models were calculated separately for each subgroup.

RESULTS

Of 259 patients enrolled in the VANISH trial [median age 69.8 (IQR 63.0-74.2) years, 7.0% women], 135 had an inferior MI, 124 a non-inferior MI, and 83 an anterior MI. Among patients with an inferior MI, no statistically significant difference in the primary outcome was detected between patients randomized to ablation or escalated therapy [aHR 0.78 (95% CI 0.51-1.20)]. In contrast, patients with non-inferior MIs had a statistically significant reduction in the incidence of the primary outcome with ablation [aHR 0.48 (95% CI 0.27-0.86)]; which was of greater magnitude than the reduction observed in the overall results of the VANISH trial [HR 0.72 (95% CI 0.53-0.98)]. In addition, a trend towards a reduction in the primary outcome with ablation was detected in patients with anterior MIs [aHR 0.50 (95% CI 0.23-1.09)].

CONCLUSION

The effectiveness of VT ablation versus escalated pharmacological therapy varies based on the location of the MI. Patients with MI scars located only in non-inferior regions of the ventricles derive greater benefit from VT ablation in reducing VT-related events. Further studies are required to explore reasons for this finding and to assess the impact of VT treatment strategies based on MI location in optimizing outcomes.

Remote-only monitoring for patients with cardiac implantable electronic devices: a before-and-after pilot study

BACKGROUND

Outcomes for patients with cardiac implantable electronic devices are better when follow-up incorporates remote monitoring technology in addition to in-clinic visits. For patients with implantable devices, we sought to determine the feasibility, safety and associated health care utilization of remote-only follow-up, along with its effects on patients' quality of life and costs.

METHODS

This multicentre before-and-after pilot study involved patients with new or existing pacemakers or implantable cardioverter defibrillators. The "before" phase of the study spanned the period October 2015 to February 2017; the "after" phase spanned the period October 2016 to February 2018. The exposure was remote-only follow-up in combination with Remote View, a service that facilitates access to device data, allowing device settings to be viewed remotely to facilitate remote programming. Outcomes at 12 months were feasibility (adherence to remote monitoring), safety (rate of adverse events) and health care utilization (remote and in-clinic appointments). We also assessed quality of life, using 3 validated scales, and costs, taking into account both health care system and patient costs.

RESULTS

A total of 176 patients were enrolled. Adherence (defined as at least 1 successful remote transmission during follow-up) was 87% over a mean follow-up of 11.7 (standard deviation 2.2) months. There was a reduction in in-clinic visits at specialized sites among patients with both implantable defibrillators (26 v. 5, p < 0.001, n = 48) and pacemakers (42 v. 10, p < 0.001, n = 51). There was no significant change in visits to community sites for patients with defibrillators (13 v. 17, p = 0.3, n = 48). The composite rate of death, stroke, cardiovascular hospitalization and device-related hospitalization was 7% (n = 164). No adverse events were linked to the intervention. There was no change in quality-of-life scales between baseline and 12 months. Health care costs were reduced by 31% for patients with defibrillators and by 44% for those with pacemakers.

INTERPRETATION

This pilot study showed the feasibility of remote-only follow-up, with no increase in adverse clinical outcomes and no effect on quality of life, but with reductions in costs and health care utilization. These results support progression to a larger-scale study of whether superior effectiveness and reduced cost can be achieved, with preservation of safety, through use of remote-only follow-up.

TRIAL REGISTRATION

ClinicalTrials.gov, no. NCT02585817.

Optimum lesion set and predictors of outcome in persistent atrial fibrillation ablation: a meta-regression analysis

AIMS

Ablation of persistent atrial fibrillation (PsAF) has been performed by many techniques with varying success rates. This may be due to ablation techniques, patient demographics, comorbidities, and trial design. We conducted a meta-regression of studies of PsAF ablation to elucidate the factors affecting atrial fibrillation (AF) recurrence.

METHODS AND RESULTS 

Databases were searched for prospective studies of PsAF ablation. A meta-regression was performed. Fifty-eight studies (6767 patients) were included. Complex fractionated atrial electrogram (CFAE) ablation reduced freedom from AF by 8.9% [95% confidence interval (CI) -15 to -2.3, P = 0.009). Left atrial appendage [LAA isolation (three study arms)] increased freedom from AF by 39.5% (95% CI 9.1-78.4, P = 0.008). Posterior wall isolation (PWI) (eight study arms) increased freedom from AF by 19.4% (95% CI 3.3-38.1, P = 0.017). Linear ablation or ganglionated plexi ablation resulted in no significant effect on freedom from AF. More extensive ablation increased intraprocedural AF termination; however, intraprocedural AF termination was not associated with improved outcomes. Increased left atrial diameter was associated with a reduction in freedom from AF by 4% (95% CI -6.8% to -1.1%, P = 0.007) for every 1 mm increase in diameter.

CONCLUSION 

Linear ablation, PWI, and CFAE ablation improves intraprocedural AF termination, but such termination does not predict better long-term outcomes. Study arms including PWI or LAA isolation in the lesion set were associated with improved outcomes in terms of freedom from AF; however, further randomized trials are required before these can be routinely recommended. Left atrial size is the most important marker of AF chronicity influencing outcomes.

915ATP efficacy on terminating ventricular tachycardia by device type, indication, and ventricular median cycle length

Funding Acknowledgements

Medtronic

OnBehalf

PainFree SST

Background

Anti-tachycardia Pacing (ATP) is an established therapy that terminates VT without the need for painful ICD shocks. Here we use the data from PainFree SST clinical trial to evaluate the ATP success rate by device type, indication and MCL. 

Methods

Spontaneous episodes that were detected by ICD or CRT-D devices in the VT, fast VT and VF zones were included in the analysis. Episodes successfully terminated by ATP were deemed as having ATP success. Using the GEE method, ATP success rate and its 95% CI were calculated for device types, indications and ventricular MCL. 

Results

Of the 2770 enrolled patients (79% male, average age 65 years), 1699 (61%) were implanted with an ICD and 1071 (39%) with a CRT-D system; 1917 (69%) were reported as primary prevention and 847 (31%) were secondary prevention patients. For all MVT episodes, the ATP success rate was similar between ICD and CRT-D devices (82.3% vs 80.3%, p = 0.74). Patients with secondary prevention had a higher ATP success rate compared to those with primary prevention but the difference was not statistically significant (84.4% vs 76.8%, p = 0.16). Regardless of device type and indication, ATP success rate was significantly higher in the slower VTs (MCL ≥ 320 ms) compared to the faster VTs (MCL ≥ 240 to &lt; 320 ms) (89.2% vs 73.7%, p &lt; 0.0001). 

Conclusion

We found that ATP had a greater than 80% rate of success for terminating ventricular tachycardias overall. Slower VTs was significantly associated with a higher ATP success rate regardless of device type and indication compared to faster VTs. For faster VTs with a MCL ≥ 240 to &lt; 320 ms, the ATP success rate was still successful at terminating VT more than 70% of the time.

Table 1. ATP Success Rates - No. of Enrolled Subjects (% of total) No. of Episodes Analyzed for ATP Success (No. of Subjects) GEE-estimated ATP Success Rate (95% CI) P-value* Overall 2770 (100%) 2277 (376) 81.5% (78.4%, 84.2%) - Device Type - - - 0.7440 ICD 1699 (61.3%) 1484 (229) 82.3% (78.3%, 85.6%) - CRT-D 1071 (38.7%) 793 (147) 80.3% (75.0%, 84.6%) - Indication - - - 0.1609 Primary Prevention 1917 (69.2%) 631 (160) 76.8% (71.2%, 81.6%) - Secondary Prevention 847 (30.6%) 1615 (212) 84.4% (80.7%, 87.6%) - Median Cycle Length - - - &lt;0.0001 (&gt;/=) 240 ms and &lt; 320 ms - 861 (257) 73.7% (69.2%, 77.7%) - (&gt;/=) 320 ms - 1416 (209) 89.2% (85.7%, 91.9%) - * Per a GEE main effect model for all episodes where device type, indication and median cycle length were considered.

Defibrillator shocks and their effect on objective and subjective patient outcomes: Results of the PainFree SST clinical trial

BACKGROUND

The effect of implantable cardioverter-defibrillator (ICD) shock on device-measured activity and patient-reported outcomes is unknown.

OBJECTIVE

The purpose of this study was to analyze the acute and long-term effects of ICD shock on objective behavioral data (ie, device-based physical activity) and subjective patient-reported outcomes (eg, quality of life and shock anxiety).

METHODS

The PainFree Smart Shock Technology (SST) clinical trial included 2770 patients with a single- or dual-chamber ICD or cardiac resynchronization therapy - defibrillator device who were followed for 22 ± 9 months. Participants completed measures of quality of life (EuroQol-5D [EQ-5D] questionnaire) and shock anxiety (Florida Shock Anxiety Scale) at baseline, biannual visits, and monthly for 6 months after an ICD shock. Daily physical activity data were obtained from a built-in device accelerometer.

RESULTS

The average daily activity was 185.3 ± 119.4 min/d. Activity was significantly reduced after an ICD shock (P < .0001) and recovered to a normal level after ∼90 days. An ICD shock was also associated with decreased quality of life (EQ5-D health score) and increased EQ-5D anxiety scores, but it did not affect mobility, self-care, activity, or pain. Similarly, shock anxiety (Florida Shock Anxiety Scale) increased in shocked patients and remained significantly elevated at 24 months, regardless of appropriate or inappropriate shock delivery.

CONCLUSION

ICD shocks have a long-lasting adverse effect on both objective, device-measured physical activity and subjective patient-reported outcomes of quality of life and shock anxiety. Successful management of patients with an ICD requires attention to clinically relevant behavioral and psychological outcomes to expedite recovery and return to activities of daily living.

Inappropriate shocks in single-chamber and subcutaneous implantable cardioverter-defibrillators: a systematic review and meta-analysis

AIMS

Single-chamber (VR-ICD) and subcutaneous (S-ICD) implantable cardioverter-defibrillators are effective to protect patients against sudden death but expose them to higher risk of inappropriate shock (IS). We sought to quantify the annual rate and influencing factors of ISs in VR- and S-ICDs from the literature.

METHODS AND RESULTS

PubMed, Embase, and Cochrane Library were searched for full text articles with IS rates. Poisson distribution estimated proportion of patients with ISs; rates were annualized based on follow-up duration. Random effects meta-analysis accounted for study-to-study variation. Out of 3264 articles, 16 qualified for the meta-analysis. Across studies, 6.4% [95% confidence interval (CI) 5.1-7.9%] of patients received an IS per year. Meta-regression analyses demonstrated that IS rates were lower in more recent studies [rate ratio (RR) per year: 0.93, 95% CI: 0.87-0.98; P = 0.01] and trended lower in studies with longer follow-up (RR per year: 0.78, 95% CI: 0.60-1.01; P = 0.06). Use of S-ICDs (RR: 1.81, 95% CI: 0.86-3.81; P = 0.12) and ventricular tachycardia zone programmed on (RR: 1.13, 95% CI: 0.65-1.97; P = 0.66) were not associated with a significantly increased change in risk. The IS rate observed in one of the more recent studies was significantly lower than predicted after accounting for covariates (RR: 0.29, 95% CI: 0.14-0.60; P < 0.001).

CONCLUSIONS

A comprehensive review of the literature shows that 6.4% of patients with ICDs experienced their first IS annually. One of the 16 studies was better than predicted with the lowest reported rate (1.9%) and could not be explained by timing of the study or other covariates.

Cardiac Resynchronization Therapy Reduces Ventricular Arrhythmias in Primary but Not Secondary Prophylactic Implantable Cardioverter Defibrillator Patients

Background—

The RAFT (Resynchronization in Ambulatory Heart Failure Trial) demonstrated that cardiac resynchronization therapy (CRT) reduced both mortality and heart failure hospitalizations in patients with functional class II or III heart failure and widened QRS. We examined the influence of CRT on ventricular arrhythmias in patients with primary versus secondary prophylaxis defibrillator indications.

Methods and Results—

All ventricular arrhythmias among RAFT study participants were downloaded and adjudicated by 2 blinded reviewers with an overreader for disagreements and committee review for remaining discrepancies. Incidence of ventricular arrhythmias among patients randomized to CRT-D versus implantable cardioverter defibrillator (ICD) were compared within the groups of patients treated for primary prophylaxis and for secondary prophylaxis. Of 1798 enrolled patients, 1764 had data available for adjudication and were included. Of these, 1531 patients were implanted for primary prophylaxis, while 233 patients were implanted for secondary prophylaxis; 884 patients were randomized to ICD and 880 to CRT-D. During 5953.6 patient-years of follow-up, there were 11 278 appropriate ICD detections of ventricular arrhythmias. In the primary prophylaxis group, CRT-D significantly reduced incidence ventricular arrhythmias in comparison to ICD (hazard ratio, 0.86; 95% confidence interval, 0.74–0.99; P =0.044). This effect was not seen in the secondary prophylaxis group (hazard ratio, 1.14; 95% confidence interval, 0.82–1.58; P =0.45). CRT-D was not associated with significant differences in overall ventricular arrhythmia burden in either group.

Conclusions—

CRT reduced the rate of onset of new ventricular arrhythmias detected by ICDs in patients without a history of prior ventricular arrhythmias. This effect was not observed among patients who had prior ventricular arrhythmias.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT00251251.

Canadian Cardiovascular Society/Canadian Heart Rhythm Society 2016 Implantable Cardioverter-Defibrillator Guidelines

Sudden cardiac death is a major public health issue in Canada. However, despite the overwhelming evidence to support the use of implantable cardioverter defibrillators (ICDs) in the prevention of cardiac death there remains significant variability in implantation rates across Canada. Since the most recent Canadian Cardiovascular Society position statement on ICD use in Canada in 2005, there has been a plethora of new scientific information to assist physicians in their discussions with patients considered for ICD implantation to prevent sudden cardiac death due to ventricular arrhythmias. We have reviewed, critically appraised, and synthesized the pertinent evidence to develop recommendations regarding: (1) ICD implantation in the primary and secondary prevention of sudden cardiac death in patients with and without ischemic heart disease; (2) when it is reasonable to withhold ICD implantation on the basis of comorbidities; (3) ICD implantation in patients listed for heart transplantation; (4) implantation of a single- vs dual-chamber ICD; (5) implantation of single- vs dual-coil ICD leads; (6) the role of subcutaneous ICDs; and (7) ICD implantation infection prevention strategies. We expect that this document, in combination with the companion article that addresses the implementation of these guidelines, will assist all medical professionals with the care of patients who have had or at risk of sudden cardiac death.

Ventricular Tachycardia Ablation versus Escalation of Antiarrhythmic Drugs

BACKGROUND

Recurrent ventricular tachycardia among survivors of myocardial infarction with an implantable cardioverter-defibrillator (ICD) is frequent despite antiarrhythmic drug therapy. The most effective approach to management of this problem is uncertain.

METHODS

We conducted a multicenter, randomized, controlled trial involving patients with ischemic cardiomyopathy and an ICD who had ventricular tachycardia despite the use of antiarrhythmic drugs. Patients were randomly assigned to receive either catheter ablation (ablation group) with continuation of baseline antiarrhythmic medications or escalated antiarrhythmic drug therapy (escalated-therapy group). In the escalated-therapy group, amiodarone was initiated if another agent had been used previously. The dose of amiodarone was increased if it had been less than 300 mg per day or mexiletine was added if the dose was already at least 300 mg per day. The primary outcome was a composite of death, three or more documented episodes of ventricular tachycardia within 24 hours (ventricular tachycardia storm), or appropriate ICD shock.

RESULTS

Of the 259 patients who were enrolled, 132 were assigned to the ablation group and 127 to the escalated-therapy group. During a mean (±SD) of 27.9±17.1 months of follow-up, the primary outcome occurred in 59.1% of patients in the ablation group and 68.5% of those in the escalated-therapy group (hazard ratio in the ablation group, 0.72; 95% confidence interval, 0.53 to 0.98; P=0.04). There was no significant between-group difference in mortality. There were two cardiac perforations and three cases of major bleeding in the ablation group and two deaths from pulmonary toxic effects and one from hepatic dysfunction in the escalated-therapy group.

CONCLUSIONS

In patients with ischemic cardiomyopathy and an ICD who had ventricular tachycardia despite antiarrhythmic drug therapy, there was a significantly lower rate of the composite primary outcome of death, ventricular tachycardia storm, or appropriate ICD shock among patients undergoing catheter ablation than among those receiving an escalation in antiarrhythmic drug therapy. (Funded by the Canadian Institutes of Health Research and others; VANISH ClinicalTrials.gov number, NCT00905853.).

Extended detection time to reduce shocks is safe in secondary prevention patients: The secondary prevention substudy of PainFree SST

BACKGROUND

Prolonged ventricular fibrillation (VF) detection has been shown to reduce implantable cardioverter-defibrillator (ICD) therapies and improve prognosis in primary prevention ICD patients. Data in secondary prevention patients are limited.

OBJECTIVE

The PainFree SST secondary prevention study is the largest trial of secondary prevention patients randomized between standard and prolonged detection to assess the safety of this strategy in these patients.

METHODS

A total of 705 secondary prevention patients implanted with an ICD in the PainFree SST trial were enrolled in this substudy; 353 patients were randomized to VF detection of 18/24 intervals and 352 patients to 30/40. All other VF parameters were standardized by protocol.

RESULTS

The 1-year arrhythmic syncope-free rates in the standard and prolonged groups were 97.7% vs 96.9%, respectively, (P = .0034 for noninferiority). Freedom from all-cause syncope was 96% in both arms (P = .0013 for noninferiority). There was no difference in the time to first appropriate or inappropriate VF therapy. However, the rates of treated VF episodes were lower in the prolonged arm (1.48 per patient per year vs 0.44 per patient per year, P = .0001). A trend toward lower mortality in the prolonged group was not statistically different (5.6% 1 year, 12% 2 years vs 3.8% 1 year, 7.7% 2 years, adjusted hazard ratio = 0.60, P = .061).

CONCLUSION

This large prospective randomized study shows that prolonged detection can safely be programmed in secondary prevention ICD patients with new or existing devices. This programming strategy decreases the rate of treated events and is not associated with an increased risk of syncope or mortality.

Incidence, predictors, and procedural results of upgrade to resynchronization therapy: the RAFT upgrade substudy

BACKGROUND

The resynchronization-defibrillation for ambulatory heart failure trial (RAFT) study demonstrated that adding cardiac resynchronization therapy (CRT) in selected patients requiring de novo implantable cardiac defibrillators (ICD) reduced mortality as compared with ICD therapy alone, despite an increase in procedure-related adverse events. Data are lacking regarding the management of patients with ICD therapy who develop an indication for CRT upgrade.

METHODS AND RESULTS

Participating RAFT centers provided data regarding de novo CRT-D (CRT with ICD) implant, upgrade to CRT-D during RAFT (study upgrade), and upgrade within 6 months after presentation of study results (substudy). Substudy centers enrolled 1346 (74.9%) patients in RAFT, including 644 de novo, 80 study upgrade, and 60 substudy CRT attempts. The success rate (initial plus repeat attempts) was 95.2% for de novo versus 96.3% for study upgrade and 90.0% for substudy CRT attempts (P=0.402). Acute complications occurred among 26.2% of de novo versus 18.8% of study upgrade and 3.4% of substudy CRT implantation attempts (P<0.001). The most common complication was left ventricular lead dislodgement. The principal reasons for not yet attempting upgrade in the substudy were patient preference (31.9%), New York Heart Association Class I (17.0%), and a QRS<150 ms (13.1%).

CONCLUSIONS

Among a broad group of implant physicians, CRT upgrades were performed in patients with an ICD in situ with no difference in implant success rate and a reduced acute complication rate as compared with a de novo CRT implant. Decisions to upgrade were influenced by predictors of benefit in subgroup analyses of the RAFT study and other trials.

Esophageal perforation after radiofrequency ablation for atrial fibrillation

A 69-year-old man underwent left atrial radiofrequency ablation for atrial fibrillation. After 10 minutes, the procedure was terminated due to pericardial tamponade secondary to perforation during mapping. Pericardiocentesis resolved the tamponade. Ablation was completed one week later, and the patient was discharged. Two days later, he presented with odynophagia. Computed tomography demonstrated small bilateral pleural effusions. He was judged to be stable and was discharged again, but returned 2 days later with chest pain. He was found to have esophageal perforation with empyema, which was repaired using a muscle patch and esophageal stenting, successfully treating the lesion with minimal morbidity.

Radiofrequency ablation vs antiarrhythmic drugs as first-line treatment of paroxysmal atrial fibrillation (RAAFT-2): a randomized trial

IMPORTANCE

Atrial fibrillation (AF) is the most common rhythm disorder seen in clinical practice. Antiarrhythmic drugs are effective for reduction of recurrence in patients with symptomatic paroxysmal AF. Radiofrequency ablation is an accepted therapy in patients for whom antiarrhythmic drugs have failed; however, its role as a first-line therapy needs further investigation.

OBJECTIVE

To compare radiofrequency ablation with antiarrhythmic drugs (standard therapy) in treating patients with paroxysmal AF as a first-line therapy.

DESIGN, SETTING, AND PATIENTS

A randomized clinical trial involving 127 treatment-naive patients with paroxysmal AF were randomized at 16 centers in Europe and North America to received either antiarrhythmic therapy or ablation. The first patient was enrolled July 27, 2006; the last patient, January 29, 2010. The last follow-up was February 16, 2012.

INTERVENTIONS

Sixty-one patients in the antiarrhythmic drug group and 66 in the radiofrequency ablation group were followed up for 24 months.

MAIN OUTCOMES AND MEASURES

The time to the first documented atrial tachyarrhythmia of more than 30 seconds (symptomatic or asymptomatic AF, atrial flutter, or atrial tachycardia), detected by either scheduled or unscheduled electrocardiogram, Holter, transtelephonic monitor, or rhythm strip, was the primary outcome. Secondary outcomes included symptomatic recurrences of atrial tachyarrhythmias and quality of life measures assessed by the EQ-5D tool.

RESULTS

Forty-four patients (72.1%) in the antiarrhythmic group and in 36 patients (54.5%) in the ablation group experienced the primary efficacy outcome (hazard ratio [HR], 0.56 [95% CI, 0.35-0.90]; P = .02). For the secondary outcomes, 59% in the drug group and 47% in the ablation group experienced the first recurrence of symptomatic AF, atrial flutter, atrial tachycardia (HR, 0.56 [95% CI, 0.33-0.95]; P = .03). No deaths or strokes were reported in either group; 4 cases of cardiac tamponade were reported in the ablation group. In the standard treatment group, 26 patients (43%) underwent ablation after 1-year. Quality of life was moderately impaired at baseline in both groups and improved at the 1 year follow-up. However, improvement was not significantly different among groups.

CONCLUSIONS AND RELEVANCE

Among patients with paroxysmal AF without previous antiarrhythmic drug treatment, radiofrequency ablation compared with antiarrhythmic drugs resulted in a lower rate of recurrent atrial tachyarrhythmias at 2 years. However, recurrence was frequent in both groups.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00392054.

The role of device diagnostic algorithms in the assessment and management of patients with systolic heart failure: a review

Hospitalization due to heart failure (HF) exacerbation represents a major burden in health care and portends a poor long-term prognosis for patients. As a result, there is considerable interest to develop novel tools and strategies to better detect onset of volume overload, as HF hospitalizations may be reduced if appropriate interventions can be promptly delivered. One such innovation is the use of device-based diagnostic parameters in HF patients with implantable cardioverter defibrillators (ICD) and/or cardiac resynchronization therapy (CRT) devices. These diagnostic algorithms can effectively monitor and detect changes in patients' HF status, as well as predict one's risk of HF hospitalization. This paper will review the role of these device diagnostics parameters in the assessment and management of HF patients in ambulatory settings. In addition, the integration of these novel algorithms in existing HF disease management models will be discussed.

A wide complex tachycardia with changing atrial activation sequence

Change of the retrograde atrial activation sequence during radiofrequency (RF) ablation of left-side accessory pathway can be due to another accessory pathway, another mechanism for the tachycardia, or due to intraatrial conduction block, partial or complete, caused by RF delivery to a site proximal to the site of insertion of the accessory pathway. In this case report, a temporary complete intraatrial conduction block was created by RF delivery proximal to the site of accessory pathway insertion, causing a change in the retrograde atrial activation sequence during ongoing tachycardia that was terminated by ablation at the insertion site of accessory pathway.

Double transseptal puncture for catheter ablation of atrial fibrillation: safety of the technique and its use in the outpatient setting

Introduction. For pulmonary vein isolation in patients with atrial fibrillation (AF), some centers use the double transseptal puncture technique for catheter access in order to facilitate catheter manipulation within the left atrium. However, no safety data has so far been published using this approach. Method. 269 ablation procedures were performed in 243 patients (mean age 56.6 ± 9.3 years, 75% men) using the double transseptal puncture for catheter access in all cases. Patients were considered for ablation of paroxysmal (80%), persistent (19%), and permanent (1%) AF. 230 procedures were performed on an outpatient basis (85.5%), and 26 were repeat procedures (9.7%). Results. The double transseptal puncture catheter access was successfully achieved in all patients. The procedural success with the endpoint of pulmonary vein isolation was reached in 255 procedures (95%). A total of 1048 out of 1062 pulmonary veins (99%) were successfully isolated. Major complications occurred in eight patients (3.0%). Of these, seven patients (2.6%) had pericardial effusion requiring percutaneous drainage, and one patient (0.4%) suffered a minor reversible stroke. One patient (0.4%) had a minor air embolism with transient symptoms. Conclusion. The double transseptal puncture catheterization technique allows easy catheter manipulation within the left atrium to reach the goal of acute procedural success in AF ablation. Procedure-related complications are rare, and the technique can be used safely for AF ablation in the outpatient setting.

A comparison of empiric to physician-tailored programming of implantable cardioverter-defibrillators: results from the prospective randomized multicenter EMPIRIC trial

OBJECTIVES

The purpose of this randomized study was to determine whether a strategically chosen standardized set of programmable settings is at least as effective as physician-tailored choices, as measured by the shock-related morbidity of implantable cardioverter-defibrillator (ICD) therapy.

BACKGROUND

Programming of ventricular tachyarrhythmia (ventricular tachycardia [VT] or ventricular fibrillation [VF]) detection and therapy for ICDs is complex, requires many choices by highly trained physicians, and directly influences the frequency of shocks and patient morbidity.

METHODS

A total of 900 ICD patients were randomly assigned to standardized (EMPIRIC, n = 445) or physician-tailored (TAILORED, n = 455) VT/VF programming and followed for 1 year.

RESULTS

The primary end point was met: the adjusted percentages of both VT/VF (22.3% vs. 28.7%) and supraventricular tachycardia or other non-VT/VF event episodes (11.9% vs. 26.1%) that resulted in a shock were non-inferior and lower in the EMPIRIC arm compared to the TAILORED arm. The time to first all-cause shock was non-inferior in the EMPIRIC arm (hazard ratio = 0.95, 90% confidence interval 0.74 to 1.23, non-inferiority p = 0.0016). The EMPIRIC trial had a significant reduction of patients with 5 or more shocks for all-cause (3.8% vs. 7.0%, p = 0.039) and true VT/VF (0.9% vs. 3.3%, p = 0.018). There were no significant differences in total mortality, syncope, emergency room visits, or unscheduled outpatient visits. Unscheduled hospitalizations occurred significantly less often (p = 0.001) in the EMPIRIC arm.

CONCLUSIONS

Standardized empiric ICD programming for VT/VF settings is at least as effective as patient-specific, physician-tailored programming, as measured by many clinical outcomes. Simplified and pre-specified ICD programming is possible without an increase in shock-related morbidity.

A trial design for evaluation of empiric programming of implantable cardioverter defibrillators to improve patient management

The delivery of implantable cardioverter defibrillator (ICD) therapy is sophisticated and requires the programming of over 100 settings. Physicians tailor these settings with the intention of optimizing ICD therapeutic efficacy, but the usefulness of this approach has not been studied and is unknown. Empiric programming of settings such as anti-tachycardia pacing (ATP) has been demonstrated to be effective, but an empiric approach to programming all VT/VF detection and therapy settings has not been studied. A single standardized empiric programming regimen was developed based on key strategies with the intention of restricting shock delivery to circumstances when it is the only effective and appropriate therapy. The EMPIRIC trial is a worldwide, multi-center, prospective, one-to-one randomized comparison of empiric to physician tailored programming for VT/VF detection and therapy in a broad group of about 900 dual chamber ICD patients. The trial will provide a better understanding of how particular programming strategies impact the quantity of shocks delivered and facilitate optimization of complex ICD programming.