Evaluation of organized atrial arrhythmias after cryptogenic stroke

Background

Long-term rhythm monitoring to detect atrial fibrillation (AF) following a cryptogenic stroke (CS) is well established. However, the burden of organized atrial arrhythmias in this population is not well defined.

Objective

The purpose of this study was to assess the incidence and risk factors for organized atrial arrhythmias in patients with CS.

Methods

We evaluated all patients with CS who received an insertable cardiac monitor (ICM) between October 2014 and April 2020. All ICM transmissions categorized as AF, tachycardia, or bradycardia were reviewed. We evaluated the time to detection of organized AF and the combination of either organized atrial arrhythmia or AF.

Results

A total of 195 CS patients with ICMs were included (51% men; mean age 66 ± 12 years; mean CHA2DS2-VASC score 4.6). Over mean follow-up of 18.9 ± 11.2 months, organized atrial arrhythmias lasting ≥30 seconds were detected in 45 patients (23%), of whom 62% did not have AF. Seventeen patients had both organized atrial arrhythmia and AF, and another 21 patients had AF only. Compared to those with normal left atrial size, patients with left atrial enlargement had a higher adjusted risk for development of atrial arrhythmias (mild left atrial enlargement: hazard ratio 1.99; 95% confidence interval 1.06-3.75; moderate/severe left atrial enlargement: hazard ratio 3.06; 95% confidence interval 1.58-5.92).

Conclusion

Organized atrial arrhythmias lasting ≥30 seconds are detected in nearly one-fourth of CS patients. Two-thirds of these patients did not have AF. Further studies are required to evaluate the impact of organized atrial arrhythmias on recurrent stroke risk.

Three-dimensional intracardiac echocardiography for left atrial appendage sizing and percutaneous occlusion guidance

AIMS

Left atrial appendage (LAA) imaging is critical during percutaneous occlusion procedures. 3D-intracardiac echocardiography (ICE) features direct visualization of LAA from multiple cross-sectional planes at a time. We aimed at reporting procedural success of 3D-ICE-guided LAA occlusion and the correlation between pre-procedural transoesophageal echocardiography (TEE) and intraprocedural 3D-ICE for LAA sizing.

METHODS AND RESULTS

Among 274 patients undergoing left atrial appendage occlusion (LAAO) with a Watchman FLX, periprocedural ICE guidance was achieved via a commercially available 2D-ICE catheter (220 patients) or a novel (NUVISION™) 3D-ICE one (54 patients). Primary endpoint was a composite of procedural success and LAA sealing at follow-up TEE. Secondary endpoint was a composite of periprocedural device recapture/resizing plus presence of leaks ≥ 3 mm at follow-up TEE. 3D-ICE measurements of maximum landing zone correlated highly with pre-procedural TEE reference values [Pearson's: 0.94; P < 0.001; bias: -0.06 (-2.39, 2.27)]. The agreement between 3D-ICE-based device selection and final device size was 96.3% vs. 79.1% with 2D-ICE (P = 0.005). The incidence of the primary endpoint was 98.1% with 3D-ICE and 97.3% with 2D-ICE (P = 0.99). 2D-ICE patients had a trend towards a higher incidence of periprocedural device recapture/redeployment (31.5% vs. 44.5%; P = 0.09). The secondary endpoint occurred in 31.5% of 3D-ICE patients vs. 45.9% of 2D-ICE ones (P = 0.065).

CONCLUSION

Intracardiac echocardiography-guided LAAO showed a very high success, with no major adverse events. A very high level of agreement for LAA sizing was found between pre-procedural TEE and periprocedural 3D-ICE. 3D-ICE performed significantly better than 2D-ICE for FLX size selection and may provide better guidance during device deployment.

Bipolar ablation of ventricular arrhythmias: Step-by-step

Radiofrequency (RF) ablation of intramural ventricular arrhythmias (VAs) may require advanced ablation techniques to achieve effective energy transfer to the targeted tissue. As an alternative to standard RF ablation, catheter ablation can also be conducted in bipolar configuration when two ablation catheters participate in the RF circuit. This strategy has proved to result in deeper lesion formation and may be effective for eliminating arrhythmias that have been refractory to standard ablation. In this article, we provide a step-by-step guide on when and how to perform bipolar ablation of VAs.

Utility of Very High-Output Pacing to Identify VT Circuits in Patients Manifesting Traditionally Inexcitable Scar

BACKGROUND

Entrainment and pace mapping are used to identify critical components (CCs) of ventricular tachycardia (VT) circuits. In patients with dense myocardial scarring, VT circuits may elude capture at standard high pacing outputs (up to 10 mA at a 2-millisecond pulse width).

OBJECTIVES

The purpose of this study was to assess the utility of very high-output pacing (V-HOP, 50 mA at 2 milliseconds) for identifying CCs of VT circuits after standard high pacing output failed to elicit capture in densely scarred myocardial tissue.

METHODS

Our standard VT ablation approach included electroanatomic mapping for substrate characterization and entrainment and/or pace mapping to identify CCs of VT circuits. Patients that required V-HOP to capture sites of interest comprised the study cohort. Ablation endpoints were VT termination and noninducibility.

RESULTS

Twenty-five patients (71 ± 10 years of age, all males) undergoing 26 VT ablations met the inclusion criteria. The mean left ventricular ejection fraction was 30% ± 14%, and 85% had ischemic cardiomyopathy. V-HOP was used to successfully entrain VT in 17 patients, yielding central isthmus sites in 10 and entrance/exit sites in 4. VT terminated with radiofrequency ablation at these sites in 15 patients. In 9 patients, V-HOP identified scar locations with a delayed exit. Acute procedural success was achieved in 24 patients without any adverse events. Over a follow-up period of 16 ± 21 months, 2 patients experienced VT recurrence requiring repeat ablation during which the same location was targeted successfully in 1 patient.

CONCLUSIONS

In VT patients with a dense scar that is traditionally inexcitable, V-HOP can identify CCs of the re-entrant circuit and guide successful ablation.

Identifying Origin of Nonpulmonary Vein Triggers Using 2 Stationary Linear Decapolar Catheters: A Novel Algorithm

BACKGROUND

Targeting nonpulmonary vein triggers (NPVTs) of atrial fibrillation (AF) after pulmonary vein isolation can be challenging. NPVTs are often single ectopic beats with a surface P-wave obscured by a QRS or T-wave.

OBJECTIVES

The goal of this study was to construct an algorithm to regionalize the site of origin of NPVTs using only intracardiac bipolar electrograms from 2 linear decapolar catheters positioned in the posterolateral right atrium (along the crista terminalis with the distal bipole pair in the superior vena cava) and in the proximal coronary sinus (CS).

METHODS

After pulmonary vein isolation in 42 patients with AF, pacing from 15 typical anatomic NPVT sites was conducted. For each pacing site, the electrogram activation sequence was analyzed from the CS catheter (simultaneous/chevron/inverse chevron/distal-proximal/proximal-distal) and activation time (ie, CSCTAT) between the earliest electrograms from the 2 decapolar catheters was measured referencing the earliest CS electrogram; a negative CSCTAT value indicates the crista terminalis catheter electrogram was earlier, and a positive CSCTAT value indicates the CS catheter electrogram was earlier. A regionalization algorithm with high predictive value was defined and tested in a validation cohort with AF NPVTs localized with electroanatomic mapping.

RESULTS

In the study patient cohort (71% male; 43% with persistent AF, 52% with left atrial dilation), the algorithm grouped with high precision (positive predictive value 81%-99%, specificity 94%-100%, and sensitivity 30%-94%) the 15 distinct pacing sites into 9 clinically useful regions. Algorithm testing in a 98 patient validation cohort showed predictive accuracy of 91%.

CONCLUSIONS

An algorithm defined by the activation sequence and timing of electrograms from 2 linear multipolar catheters provided accurate regionalization of AF NPVTs to guide focused detailed mapping.

Cardioneuroablation for the treatment of ictal-associated cardiac asystole: case report and literature review

Background

Ictal-associated bradyarrhythmia or asystole can be a manifestation of malignant seizure syndromes. In patients with ictal-associated hypervagotonia and asystole, cardioneuroablation may provide a promising alternative to permanent pacemaker implantation.

Case summary

We present a case of a 47-year-old female with a 1.5-year history of ongoing uncontrolled seizures with multiple semiologies despite multiple antiepileptic drugs who had episodes of symptomatic severe sinus bradycardia (15-30 b.p.m.) and sinus pauses (15-16 s). She underwent a successful cardioneuroablation for ictal-induced asystole with complete resolution of bradyarrhythmias.

Discussion

This case highlights the utility of cardioneuroablation in patient with ictal-induced cardiac bradyarrhythmia and asystole. Cardioneuroablation may be an approach to avoid permanent pacemakers in this population.

Catheter ablation of atrial fibrillation in elderly and very elderly patients: safety, outcomes, and quality of life

BACKGROUND

Atrial fibrillation (AF) risk increases with age. We aim to assess the efficacy and safety of catheter ablation in the older population.

METHODS

All patients undergoing AF ablation (2013-2021) at our institution were enrolled in a prospectively maintained registry. The primary endpoint was AF recurrence. Patients were divided into 3 groups: non-elderly (< 65 years), elderly (65-75 years), and very elderly (> 75 years). Patient surveys at baseline and during follow-up were used to calculate quality of life (QoL) metrics: the AF severity score as well as the AF burden.

RESULTS

A total of 7020 patients were included (42% non-elderly, 42% elderly, and 16% very elderly). Periprocedural major complications were low (< 1.5%) and similar in all groups besides pericardial effusion which was more frequent with older age and similar between the elderly and very elderly. At 3 years, AF recurrence for persistent AF (PersAF) was highest in the very elderly group (48%), followed by the elderly group (42%), and was the lowest in the non-elderly group (36%). In paroxysmal AF (PAF), there was no difference in AF recurrence between the elderly and non-elderly, while the very elderly remained associated with a significantly increased risk. Multivariable Cox analysis confirmed these findings (PersAF; elderly: HR = 1.23, P = 0.003; very elderly: HR = 1.44, P < 0.001) (PAF; elderly: HR = 1.04, P = 0.62; very elderly: HR = 1.30, P = 0.01). Catheter ablation resulted in a significant improvement in quality of life, irrespective of age group.

CONCLUSION

Catheter ablation in elderly and very elderly patients is safe, efficacious, and associated with QoL benefits. Overall, major complications were minimal and did not differ significantly between age groups, with the exception of pericardial effusions which were higher in the elderly and very elderly compared to non-elderly adults. Very elderly patients had a higher rate of AF recurrence when compared with elderly or non-elderly patients. Nevertheless, ablation resulted in a remarkable improvement in QoL and a reduction of AF burden and AF symptoms with a similar magnitude, irrespective of age.

Outcomes of catheter ablation of atrial tachyarrhythmia guided exclusively by activation mapping

INTRODUCTION

Complex atrial tachyarrhythmias (CATs) are commonly observed in patients with prior catheter ablation or cardiac surgery. These arrhythmias are challenging to map and ablate. Historically, entrainment mapping was utilized to characterize CAT. With the advent of high-definition mapping (HDM), full visualization of the CAT circuit is possible which may obviate the need for entrainment mapping.

METHODS

We sought to investigate the outcomes of catheter ablation of CAT guided only by HDM. Consecutive patients who underwent CAT ablation from 2017 to 2021 were included in our study (excluding right atrial tachyarrhythmias). Patients were sorted by the type of mapping performed. Group I consisted of patients where HDM alone was utilized with no attempt of entrainment. Group II consisted of patients where both entrainment and HDM were utilized.

RESULTS

A total of 67 patients were included in our study, with 40 patients in HDM group (I) and 27 patients in entrainment group (II). No statistically significant difference regarding 1-year freedom from atrial arrhythmias was found between the two groups (80% vs 77.8%, p = 0.819). Four CATs were terminated by entrainment during procedure versus none in the HDM-only group (p = 0.011).

CONCLUSIONS

CAT ablation with HDM alone yielded similar 1-year freedom from atrial arrhythmias compared to ablation with HDM and entrainment. Entrainment combined with HDM was associated with higher undesired CAT interruption rate. Further validation is needed with randomized control trials.

Presence of sinus rhythm at time of ablation in patients with persistent atrial fibrillation undergoing pulmonary vein isolation is associated with improved long-term arrhythmia outcomes

BACKGROUND

Adverse structural and electrical remodeling underlie persistent atrial fibrillation (PersAF). Restoration of sinus rhythm (SR) prior to ablation in PersAF may improve the underlying substrate, thus improving arrhythmia outcomes. The aim of this study was to evaluate if the presence of SR at time of ablation is associated with improved long-term arrhythmia outcomes of a limited catheter ablation (CA) strategy in PersAF.

METHODS

Patients with PersAF undergoing pulmonary vein isolation at our institution from 2014-2018 were included. We compared patients who presented for ablation in SR (by cardioversion and/or antiarrhythmic drugs [AADs]) to those who presented in AF. Primary outcome of interest was freedom from atrial arrhythmias (AAs) on or off AADs at 1 year after single ablation. Secondary outcomes included freedom from AAs on or off AADs overall, freedom from AAs off AADs at 1 year, and time to recurrent AF.

RESULTS

Five hundred seventeen patients were included (322 presented in AF, 195 SR). The primary outcome was higher in those who presented for CA in SR as compared to AF (85.6% vs. 77.0%, p = 0.017). Freedom from AAs off AAD at 12 months was also higher in those presenting in SR (59.0% vs. 44.4%; p = 0.001) and time to recurrent AF was longer (p = 0.008). Presence of SR at CA was independently associated with the primary outcome at 12 months (OR 1.77; 95% CI 1.08-2.90) and overall (OR 1.89; 95% CI 1.26-2.82).

CONCLUSIONS

Presence of SR at time of ablation is associated with improved long-term arrhythmia outcomes of limited CA in PersAF.

Ischemic or Coronary Evaluations in Patients With Monomorphic VT Electrical Storm Undergoing VT Ablation

BACKGROUND

Monomorphic ventricular tachycardia (VT) electrical storm (ES) in patients with coronary artery disease is dependent on scarred myocardium. The role of routine ischemic or coronary evaluations before ablation in patients presenting with monomorphic VT storm, without acute coronary syndrome (ACS), remains unknown.

OBJECTIVES

This study sought to assess the impact of ischemic or coronary evaluations on procedural outcomes and post-ablation mortality in monomorphic VT storm patients.

METHODS

All patients undergoing VT ablation at the Cleveland Clinic from 2014 to 2020 after presenting with monomorphic VT storm were enrolled in a prospectively maintained registry. The associations among ischemic or coronary evaluations and short-term procedural efficacy, acute outcomes, and mortality during follow-up were assessed.

RESULTS

A total of 97 consecutive patients with monomorphic VT storm in the absence of ACS underwent VT ablations. This cohort was characterized by severe LV systolic dysfunction (mean left ventricular ejection fraction 30.3%, 67% with known ischemic cardiomyopathy) with moderately severe heart failure (median NYHA functional class II); 45% of patients underwent ischemic or coronary evaluations via coronary angiography (10%), noninvasive myocardial perfusion (26%), or both (9%). The yield of these evaluations was low: No acute coronary occlusions were identified. There was no association between ischemic evaluation and acute ablation outcomes or mortality during follow-up. Similarly, in a secondary analysis, the yield of ischemic or coronary evaluations in patients with monomorphic VT storm and known coronary disease (regardless of ablation status) was found to be low.

CONCLUSIONS

Ischemic evaluations in patients with monomorphic VT storm without ACS may not improve procedural outcomes or mortality after ablation.

Septal Substrate Ablation Guided by Delayed Transmural Conduction Times: A Novel Ablation Approach to Target Intramural Substrates

BACKGROUND

Intraprocedural identification of intramural septal substrate for ventricular tachycardia (ISS-VT) in nonischemic cardiomyopathy (NICM) is challenging. Delayed (>40 ms) transmural conduction time (DCT) with right ventricular basal septal pacing has been previously shown to identify ISS-VT.

OBJECTIVES

This study sought to determine whether substrate catheter ablation incorporating areas of DCT may improve acute and long-term outcomes.

METHODS

We included patients with NICM and ISS-VT referred for catheter ablation between 2016 and 2020. ISS-VT was defined by the following: 1) confluent septal areas of low unipolar voltage (<8.3 mV) in the presence of normal or minimal bipolar abnormalities; and 2) presence of abnormal electrograms in the septum. Substrate ablation was guided by the following: 1) activation and/or entrainment mapping for tolerated VT and pace mapping with ablation of abnormal septal electrograms for unmappable VTs (n = 57, Group 1); and 2) empirically extended to target areas of DCT during right ventricular basal septal pacing regardless of their participation in inducible VT(s) but sparing the conduction system when possible (n = 24, Group 2).

RESULTS

There were no significant baseline differences between Groups 1 and 2. Noninducibility of any VT programmed stimulation at the end of ablation was higher in Group 2 compared with Group 1 (80% vs 53%; P = 0.03). At 12-month follow-up, single-procedure VT-free survival was significantly higher (79% vs 46%; P = 0.006) and the time to VT recurrence was longer (mean 10 ± 3 months vs 7 ± 4 months; P = 0.02) in Group 2 compared with Group 1.

CONCLUSIONS

In patients with NICM and ISS-VT, a substrate ablation strategy that incorporates areas of DCT appears to improve freedom from recurrent VT.

Catheter-Based Electroporation: A Novel Technique for Catheter Ablation of Cardiac Arrhythmias

Catheter ablation of arrhythmias is now standard of care in invasive electrophysiology. Current ablation strategies are based on the use of thermal energy. With continuous efforts to optimize thermal energy delivery, effectiveness has greatly improved; however, safety concerns persist. This review focuses on a novel ablation technology, irreversible electroporation (IRE), also known as pulsed-field ablation which may be a safer alternative for arrhythmia management. Pulsed-field ablation is thought to be a nonthermal ablation that applies short-duration high-voltage electrical fields to ablate myocardial tissue with high selectivity and durability while sparing important neighboring structures such as the esophagus and phrenic nerves. There are multiple ongoing studies investigating the potential superior outcomes of IRE compared to radiofrequency ablation in treating patients with atrial and ventricular arrhythmias. In this review, we describe the current evidence of preclinical and clinical trials that have shown promising results of catheter-based IRE.

Atrial Transseptal Catheterisation: Challenging Scenarios and Techniques to Overcome Them

Atrial transseptal catheterisation is a fundamental skill of any interventional electrophysiologist. In this review, various scenarios that pose unique challenges to atrial transseptal catheterisation are discussed. These scenarios include post-surgical or congenital malformations of the interatrial septum, presence of interatrial septal closure devices, absent or obstructed inferior vena cava and complex congenital heart disease after palliative surgery. Transseptal catheterisation in all of the above situations is feasible and can be performed safely with the aid of dedicated tools and specific techniques.

Twenty-five years of catheter ablation of ventricular tachycardia: a look back and a look forward

This article will discuss the past, present, and future of ventricular tachycardia ablation and the continuing contribution of the Europace journal as the platform for publication of milestone research papers in this field of ventricular tachycardia ablation.

Substrate Imaging Before Catheter Ablation of Ventricular Tachycardia: Risk Prediction for Acute Hemodynamic Decompensation

BACKGROUND

The PAINESD (Pulmonary disease, Age, Ischemic cardiomyopathy, NYHA functional class, Ejection fraction, Storm, Diabetes mellitus) risk score has been validated as a predictor of periprocedural acute hemodynamic decompensation (AHD) in patients undergoing ventricular tachycardia (VT) ablation. Whether the addition of total scar volume (TSV) determined by preprocedure computed tomography imaging provides additional risk stratification has not been previously investigated.

OBJECTIVES

The purpose of this study was to evaluate the impact of TSV on the risk of AHD and its adjunctive benefit to the PAINESD score newly modified as Pulmonary disease, Age, Ischemic cardiomyopathy, NYHA class, Ejection fraction, Storm, Scar volume, Diabetes mellitus (PAINES2D) based on the addition of scar volumes.

METHODS

This was a retrospective analysis of all index VT ablations at a quaternary care center from 2017 to 2022. Associations between TSV and AHD were evaluated among patients with structural heart disease.

RESULTS

Among 61 patients with TSV data, 13 (21%) had periprocedural AHD. TSV and PAINESD were independently associated with AHD risk. Both TSV and PAINESD were associated with AHD (P = 0.016 vs P = 0.053, respectively). The highest TSV tertile (≥37.30 mL) showed significant association with AHD (P = 0.018; OR: 4.80) compared to the other tertiles. The PAINESD and PAINES2D scores had significant impact on AHD (P = 0.046 and P = 0.010, respectively). The PAINES2D score had a greater impact on AHD compared to PAINESD (area under the curve: 0.73; P = 0.011; 95% CI: 0.56-0.91 and area under the curve: 0.67; P = 0.058; 95% CI: 0.49-0.85, respectively).

CONCLUSIONS

Addition of TSV to a modified PAINESD score, PAINES2D, enhances risk prediction of AHD. Further prospective study is needed to assess benefit in various cardiomyopathy populations undergoing VT ablation.

Procedural Adaptations to Avoid Haemodynamic Instability During Catheter Ablation of Scar-related Ventricular Tachycardia

Classically, catheter ablation for scar-related ventricular tachycardia (VT) relied upon activation and entrainment mapping of induced VT. Advances in post-MI therapies have led to VTs that are faster and haemodynamically less stable, because of more heterogeneous myocardial fibrosis patterns. The PAINESD score is one means of identifying patients at highest risk for haemodynamic decompensation during attempted VT induction, who may, therefore, benefit from alternative ablation strategies. One strategy is to use temporary mechanical circulatory support, although this warrants formal assessment of cost-effectiveness. A second strategy is to minimise or avoid VT induction altogether by employing a family of 'substrate'-based approaches aimed at identifying VT isthmuses during sinus or paced rhythm. Substrate mapping techniques are diverse, and focus on the timing, morphology and amplitude of local ventricular electrograms - sometimes aided by advanced non-invasive cardiac imaging modalities. In this review, the evolution of VT ablation over time is discussed, with an emphasis on procedural adaptations to the challenge of haemodynamic instability.

Atrial Fibrillation Ablation in Young Adults: Measuring Quality of Life Using Patient-Reported Outcomes Over 5 Years

BACKGROUND

Ablation is used for both rhythm control and improved quality of life (QoL) in atrial fibrillation (AF). It has been suggested that young adults may experience high recurrence rates after ablation and data remain lacking regarding QoL benefits. We aimed to investigate AF ablation outcomes and QoL benefits in young adults undergoing AF ablation using a large prospectively maintained registry and automated patient-reported outcomes (PRO).

METHODS

All patients undergoing AF ablation (2013-2016) at our center were prospectively enrolled. Patients aged 50 years or younger were included. For PROs, QoL measures and symptoms were assessed at baseline, 3 months after ablation, and every 6 months thereafter. The AF severity score served as the main assessment of QoL.

RESULTS

A total of 241 young adults (age, 16-50 years) were included (17% female, 40.3% persistent AF). In all, 77.2% of patients remained arrhythmia-free during the first year of follow-up (80% in nonstructural AF and 66% in structural AF). Using PROs, 90% of patients reported improvement in QoL throughout all survey time points up to 5 years postablation (P<0.0001). The baseline median AF severity score was 14 and improved to between 2 and 4 on all follow-up after ablation (P<0.0001). Patients also reported fewer and shorter AF episodes, fewer emergency room visits secondary to AF, and fewer hospitalizations (P<0.0001).

CONCLUSIONS

Ablation remains an effective rhythm-control strategy in young adults with AF. Young adults also experience significant improvement in QoL with reduction of the frequency and duration of AF episodes and AF-related healthcare utilization.

Catheter ablation of intramural outflow tract premature ventricular complexes: a multicentre study

AIMS

Ablation of outflow tract ventricular arrhythmias may be limited by a deep intramural location of the arrhythmogenic source. This study evaluates the acute and long-term outcomes of patients undergoing ablation of intramural outflow tract premature ventricular complexes (PVCs).

METHODS AND RESULTS

This multicenter series included patients with structurally normal heart or nonischemic cardiomyopathy and intramural outflow tract PVCs defined by: (a) ≥ 2 of the following criteria: (1) earliest endocardial or epicardial activation < 20ms pre-QRS; (2) Similar activation in different chambers; (3) no/transient PVC suppression with ablation at earliest endocardial/epicardial site; or (b) earliest ventricular activation recorded in a septal coronary vein. Ninety-two patients were included, with a mean PVC burden of 21.5±10.9%. Twenty-six patients had had previous ablations. All PVCs had inferior axis, with LBBB pattern in 68%. In 29 patients (32%) direct mapping of the intramural septum was performed using an insulated wire or multielectrode catheter, and in 13 of these cases the earliest activation was recorded within a septal vein. Most patients required special ablation techniques (one or more), including sequential unipolar ablation in 73%, low-ionic irrigation in 26%, bipolar ablation in 15% and ethanol ablation in 1%. Acute PVC suppression was achieved in 75% of patients. Following the procedure, the PVC burden was reduced to 5.8±8.4%. The mean follow-up was 15±14 months and 16 patients underwent a repeat ablation.

CONCLUSION

Ablation of intramural PVCs is challenging; acute arrhythmia elimination is achieved in 3/4 patients, and non-conventional approaches are often necessary for success.

Atrial Fibrillation can adversely impact Heart Failure with Preserved Ejection Fraction by its association with Heart Failure Progression and Mortality: A Post-Hoc Propensity Score-Matched Analysis of the TOPCAT Americas Trial

AIMS

Prevalent atrial fibrillation (AF) is associated with excess cardiovascular (CV) death (D) and hospitalizations (H) in heart failure (HF) with preserved ejection fraction (pEF). We evaluated if it had an independent role in excess CVD in HFpEF and studied its impact on cause-specific mortality and HF morbidity.

METHODS AND RESULTS

We used propensity score-matched (PSM) cohorts from the TOPCAT Americas trial to account for confounding by other co-morbidities. Two prevalent AF presentations at study entry were compared: (i) subjects with Any AF event by history or on electrocardiogram (ECG) with PSM subjects without an AF event and (ii) subjects in AF on ECG with PSM subjects in sinus rhythm. We analyzed cause-specific modes of death and HF morbidity during a mean follow-up period of 2.9 years. A total of 584 subjects with Any AF event and 418 subjects in AF on ECG were matched. Any AF was associated with increased CVH [hazard ratio (HR) 1.33, 95% confidence interval (CI) 1.11-1.61, P = 0.003], HFH (HR 1.44, 95% CI 1.12-1.86, P = 0.004), pump failure death (PFD) (HR 1.95, 95% CI 1.05-3.62, P = 0.035), and HF progression from New York Heart Association (NYHA) classes I/II to III/IV (HR 1.30, 95% CI 1.04-1.62, P = 0.02). Atrial fibrillation on ECG was associated with increased risk of CVD (HR 1.46, 95% CI 1.02-2.09, P = 0.039), PFD (HR 2.21, 95% CI 1.11-4.40, P = 0.024), and CVH and HFH (HR 1.37, 95% CI 1.09-1.72, P = 0.006 and HR 1.65, 95% CI 1.22-2.23, P = 0.001, respectively). Atrial fibrillation was not associated with risk of sudden death. Both Any AF and AF on ECG cohorts were associated with PFD in NYHA class III/IV HF.

CONCLUSION

Prevalent AF can be an independent risk factor for adverse CV outcomes by its selective association with worsening HF, HFH, and PFD in HFpEF. Prevalent AF was not associated with excess sudden death risk in HFpEF. Atrial fibrillation was also associated with HF progression in early symptomatic HFpEF and PFD in advanced HFpEF.

TRIAL REGISTRATION

TOPCAT trial is registered at www.clinicaltrials.gov:identifier NCT00094302.

Chronotropic Incompetence after Heart Transplantation Is Associated with Increased Mortality and Decreased Functional Capacity

INTRODUCTION

The contribution of chronotropic incompetence to reduced exercise tolerance after a heart transplant is well known, but its role as a prognostic marker of post-transplant mortality is unclear. The aim of this study is to examine the relationship between post-transplant heart rate response (HRR) and survival.

METHODS

We performed a retrospective analysis of all adult heart transplant recipients at the University of Pennsylvania between the years 2000 and 2011 who underwent a cardiopulmonary exercise test (CPET) within a year of transplant. Follow-up time and survival status were observed through October 2019, using data merged from the Penn Transplant Institute. HRR was calculated by subtracting the resting HR from the peak exercise HR. The association between HRR and mortality was analyzed using Cox proportional hazard models and Kaplan-Meier analysis. The optimal cut-off point for HRR was generated by Harrell's C statistic. Patients with submaximal exercise tests were excluded, defined by a respiratory exchange ratio (RER) cut-off of 1.05.

RESULTS

Of 277 patients with CPETs performed within a year post-transplant, 67 were excluded for submaximal exercise. In the 210 included patients, the mean follow-up time was 10.9 years (Interquartile range (IQR) 7.8-14). Resting HR and peak HR did not significantly impact mortality after adjusting for covariates. In a multivariable linear regression analysis, each 10-beat increase in heart rate response was associated with a 1.3 mL/kg/min increase in peak V_O2 and a 48 s increase in the total exercise time. Each beat/min increase in HRR was associated with a 3% reduction in the hazard of mortality (HR 0.97; 95% CI 0.96-0.99, p = 0.002). Using the optimal cut-off point generated by Harrell's C statistic, survival was significantly higher in patients with an HRR > 35 beats/min compared to those with an HRR < 35 beats/min (log rank p = 0.0012).

CONCLUSION

In heart transplant patients, a low HRR is associated with increased all-cause mortality and decreased exercise capacity. Additional studies are needed to validate whether targeting HRR in cardiac rehabilitation may improve outcomes.