Optimizing Patient Selection for Physiological Pacing in Bradyarrhythmia: Factors Associated With High Ventricular Pacing Burden.

Background: Right ventricular (RV) pacing is established as the most common ventricular pacing (VP) strategy for patients with symptomatic bradyarrhythmia. Some patients with high VP burden suffer deterioration of left ventricular (LV) function, termed pacing-induced cardiomyopathy (PICM). Patients who pace > 20% of the time from the RV apex are at increased risk of PICM, but independent predictors of increased RV pacing burden have not been elucidated in those who have a permanent pacemaker (PPM) inserted for bradyarrhythmia. Methods: We aimed to identify factors that are associated with increased VP burden > 20%, hence determining those at risk for resultant PICM. In this retrospective cohort study, we identified the most recent 300 consecutive cardiac implantable electronic device (CIED) implants in our center and collected past medical history, electrocardiogram (ECG), echo, medication and pacemaker check data. Results: A total of 236 individuals met inclusion criteria. Of the patients, 35% had RV pacing burden < 20%, while 65% had VP burden ≥ 20%; 96.2% of patients with complete heart block (CHB) paced > 20% (P = 0.002). Utilization of DDD or VVI (75.2% and 89.2% of patients, respectively) without mode switch algorithms was associated with VP > 20% (P < 0.001). Male or previous coronary artery bypass grafting (CABG) patients also statistically paced > 20%. Other factors trending towards significance included prolonged PR interval, atrial fibrillation or more advanced age. Conclusion: High-grade atrioventricular (AV) block was associated with an RV pacing burden > 20% over 3 years but this was not consistent in patients with only transient episodes of high-grade AV block. We found a significant association between high VP% and male sex, previous CABG and the absence of mode switching algorithms.

Comparing Left Atrial Low Voltage Areas in Sinus Rhythm and Atrial Fibrillation Using Novel Automated Voltage Analysis: A Pilot Study.

Background: Low voltage areas (LVAs) have been proposed as surrogate markers for left atrial (LA) scar. Correlation between voltages in sinus rhythm (SR) and atrial fibrillation (AF) have previously been measured via point-by-point analysis. We sought to compare LA voltage composition measured in SR to AF, utilizing a high-density automated voltage histogram analysis (VHA) tool in those undergoing pulmonary vein isolation (PVI) for persistent AF (PeAF). Methods: We retrospectively analyzed patients with PeAF undergoing de novo PVI. Maps required ≥ 1,000 voltage points in each rhythm and had a standardized procedure (mapped in AF then remapped in SR post-PVI). We created six anatomical segments (AS) from each map: anterior, posterior, roof, floor, septal and lateral AS. These were analyzed by VHA, categorizing atrial LVAs into 10 voltage aliquots 0 - 0.5 mV. Data were analyzed using SPSS v.26. Results: We acquired 58,342 voltage points (n = 10 patients, mean age: 67 ± 13 years, three females). LVA burdens of ≤ 0.2 mV, designated as "severe LVAs", were comparable between most AS (except on the posterior wall) with good correlation. Mapped voltages between the ranges of 0.21 and 0.5 mV were labeled as "diseased LA tissue", and these were found significantly more in AF than SR. Significant differences were seen on the roof, anterior, posterior, and lateral AS. Conclusions: Diseased LA tissue (0.21 - 0.5 mV) burden is significantly higher in AF than SR, mainly in the anterior, roof, lateral, and posterior wall. LA "severe LVA" (≤ 0.2 mV) burden is comparable in both rhythms, except with respect to the posterior wall. Our findings suggest that mapping rhythm has less effect on the LA with voltages < 0.2 mV than 0.2 - 0.5 mV across all anatomical regions, excluding the posterior wall.

Coronary Artery Ectasia: Review of the Non-Atherosclerotic Molecular and Pathophysiologic Concepts.

Coronary artery ectasia (CAE) is frequently encountered in clinical practice, conjointly with atherosclerotic CAD (CAD). Given the overlapping cardiovascular risk factors for patients with concomitant CAE and atherosclerotic CAD, a common underlying pathophysiology is often postulated. However, coronary artery ectasia may arise independently, as isolated (pure) CAE, thereby raising suspicions of an alternative mechanism. Herein, we review the existing evidence for the pathophysiology of CAE in order to help direct management strategies towards enhanced detection and treatment.

Age-Related Changes in the Anatomy of the Triangle of Koch: Implications for Catheter Ablation of Atrioventricular Nodal Re-entry Tachycardia.

BACKGROUND: Atrioventricular nodal re-entrant tachycardia is the most common type of paroxysmal supraventricular tachycardia. We sought to assess whether important anatomic factors, such as the location of the slow pathway, proximity to the bundle of His, and coronary sinus ostium dimensions, varied with patient age, and whether these factors had an impact on procedural duration, acute success, and complications. METHODS: Baseline demographic and procedural data were collected, and the maps were analyzed. Linear regression models were performed to evaluate the associations between age and these anatomic variations. Associations were also assessed, with age categorized as being ≥ 60 years or < 60 years. RESULTS: The slow pathway was more commonly located in a superior location relative to the coronary sinus ostium in older patients. The location of the slow pathway moved in a superior direction by 1 mm for every increase in 2 years from the mean estimate of age. Additionally the slow pathway tended to be closer to the coronary sinus ostium in older patients, and the diameter of the ostium was larger in older patients. This resulted in longer procedure time, longer ablation times, and a greater need for long sheaths for stability. CONCLUSIONS: The location of the slow pathway becomes more superior and closer to the coronary sinus ostium with increasing age. Additionally, the coronary sinus diameter increases with age. These factors result in longer ablation and procedural times in older patients.

CONTEXTE: La tachycardie par réentrée nodale auriculoventriculaire est le type le plus fréquent de tachycardie supraventriculaire paroxystique. Nous avons voulu évaluer si des facteurs anatomiques importants, tels que l'emplacement de la voie lente, la proximité du faisceau de His et les dimensions de l'orifice du sinus coronaire (ostium), variaient avec l'âge, et si ces facteurs avaient un effet sur la durée de l'intervention, le succès à court terme et les complications. MÉTHODOLOGIE: Des données sur les caractéristiques démographiques initiales et l'intervention ont été recueillies, et les cartes obtenues ont été analysées. Des modèles de régression linéaire ont servi à déterminer les corrélations entre l'âge et ces variations anatomiques. Les corrélations ont aussi été évaluées selon des catégories d'âge, soit ≥ 60 ans et < 60 ans. RÉSULTATS: La voie lente a été repérée plus souvent dans un emplacement supérieur par rapport à l'orifice du sinus coronaire chez les patients plus âgés. L'emplacement de la voie lente s'était déplacé de 1 mm vers le haut pour chaque augmentation de 2 ans de l'estimation moyenne de l'âge. Par ailleurs, chez les patients plus âgés, la voie lente était généralement plus proche de l'orifice du sinus coronaire et le diamètre de l'orifice était élargi. Ces variations se sont traduites par une augmentation du temps d'intervention et d'ablation et par un besoin accru de longues gaines pour la stabilité. CONCLUSIONS: L'emplacement de la voie lente devient plus éloigné vers le haut et plus proche de l'orifice du sinus coronaire avec le vieillissement. De plus, le diamètre du sinus coronaire augmente avec l'âge. Ces facteurs entraînent des temps d'ablation et d'intervention plus longs chez les patients plus âgés.

The use of minimal fluoroscopy for cardiac electrophysiology procedures: A meta-analysis and review of the literature.

BACKGROUND: Conventional catheter ablation involves prolonged exposure to ionizing radiation, potentially leading to detrimental health effects. Minimal fluoroscopy (MF) represents a safer alternative, which should be explored. Data on the safety and efficacy of this technique are limited. HYPOTHESIS: Our hypothesis is that MF is of equal efficacy and safety to conventional catheter ablation with the use of fluoroscopy by performing a meta-analysis of both randomized controlled trials (RCTs) and real-world registry studies. METHODS: Pubmed and Embase were searched from their inception to July 2020 for RCTs, cohort and observational studies that assessed the outcomes of catheter ablation using a MF technique versus the conventional approach. RESULTS: Fifteen studies involving 3795 patients were included in this meta-analysis. There was a significant reduction in fluoroscopy and procedural time with no difference in acute success (odds ratio [OR]:0.74, 95% CI: 0.50-1.10, p = .14), long-term success (OR:0.92, 95% CI: 0.65-1.31, p = .38), arrhythmia recurrence (OR:1.24, 95% CI: 0.75-2.06, p = .97) or rate of complications. (OR:0.83, 95% CI: 0.46-1.48, p = .65). Additionally sub-group analysis for those undergoing catheter ablation for atrial fibrillation (AF) did not demonstrate a difference in success or complication rates (OR:0.86, 95% CI: 0.30-2.42, p = .77). Multivariate meta-regression did not identify the presence of moderator variables. CONCLUSION: This updated meta-analysis demonstrated an overall reduction in procedural and fluoroscopy time for those undergoing a minimal fluoroscopic approach. There was no significant difference in either acute or chronic success rates or complications between a MF approach and conventional approach for the management of all arrhythmias including those undergoing catheter ablation for AF.

Catheter ablation for the management of atrial fibrillation: current technical perspectives.

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice, with a prevalence that increases alongside the ageing population worldwide. The management of AF involves restoration of sinus rhythm through antiarrhythmic drug therapy. Yet, these medications have only modest efficacy in achieving long-term success, have not shown to result in a mortality benefit, are frequently not tolerated and have associated adverse side effects. Therefore, catheter ablation has become a valuable treatment approach for AF and even a viable first-line strategy in select cases. Traditionally, the combination of radiofrequency energy and a three-dimensional electroanatomical mapping system has been used to guide catheter ablation for AF. However, single-procedural efficacy and long-term outcomes still remain suboptimal for many patients, particularly those with persistent or long-standing AF. Recent advances in ablation technology and strategy, therefore, provide new procedural approaches for catheter-based treatment with the aim of overcoming current challenges in procedural duration and overall success. The aim of this paper was to provide an updated review of the current practices and techniques relating to ablation for AF and to compare the use of these strategies for paroxysmal and persistent AF.

Canada-wide mixed methods analysis evaluating the reasons for inappropriate emergency department presentation in patients with a history of atrial fibrillation: the multicentre AF-ED trial.

OBJECTIVES: The primary objective of this study was to ascertain the reasons for emergency department (ED) attendance among patients with a history of atrial fibrillation (AF). DESIGN: Appropriate ED attendance was defined by the requirement for an electrical or chemical cardioversion and/or an attendance resulting in hospitalisation or administration of intravenous medications for ventricular rate control. Quantitative and qualitative responses were recorded and analysed using descriptive statistics and content analysis, respectively. Random effects logistic regression was performed to estimate the OR of inappropriate ED attendance based on clinically relevant patient characteristics. PARTICIPANTS: Participants ≥18 years with a documented history of AF were approached in one of eight centres partaking in the study across Canada (Ontario, Nova Scotia, Alberta and British Columbia). RESULTS: Of the 356 patients enrolled (67±13, 45% female), the majority (271/356, 76%) had inappropriate reasons for presentation and did not require urgent ED treatment. Approximately 50% of patients(172/356, 48%) were driven to the ED due to symptoms, while the remainder presented on the basis of general fear or anxiety (67/356, 19%) or prior medical advice (117/356, 33%). Random effects logistic regression analysis showed that patients with a history of congestive heart failure were significantly more likely to seek urgent care for appropriate reasons (p=0.03). Likewise, symptom-related concerns for ED presentation were significantly less likely to result in inappropriate visitation (p=0.02). When patients were surveyed on alternatives to ED care, the highest proportion of responses among both groups was in favour of specialised rapid assessment outpatient clinics (186/356, 52%). Qualitative content analysis confirmed these results. CONCLUSIONS: Improved education focused on symptom management and alleviating disease-related anxiety as well as the institution of rapid access arrhythmias clinics may reduce the need for unnecessary healthcare utilisation in the ED and subsequent hospitalisation. TRIAL REGISTRATION NUMBER: NCT03127085.

Aortic valve replacement with pulmonary hypertension: Meta-analysis of 70 676 patients.

BACKGROUND AND AIM OF THE STUDY: We compared early and late outcomes of surgical aortic valve replacement (SAVR) in patients with aortic stenosis (AS) and pulmonary hypertension (PHT). METHODS: We searched MEDLINE and EMBASE databases until July 2018 for studies comparing patients with AS and none, mild-moderate, or severe PHT undergoing SAVR. Random-effects meta-analysis was performed. RESULTS: There were 12 observational studies with 70 676 patients with median follow-up 4.0 years (interquartile range, 2.6-4 years). Compared to patients with no PHT, patients with any PHT undergoing SAVR were older (mean difference [MD], 2.31 years; 95% confidence interval [CI], 1.38-3.23 years; P < .01), with greater comorbidities and reduced ejection fraction (MD, -4.36; 95%CI, -5.94 to -2.78; P < .01). Patients with any PHT had higher unadjusted (5.2% vs 2.4%; risk ratio [RR], 2.27; 95%CI, 2.04-2.53; P < .01) and adjusted (RR, 1.65; 95%CI, 1.28-2.14; P < .01) in-hospital mortality compared with no PHT. Severe (RR, 3.53; 95%CI, 1.46-8.54; P < .01) and mild-moderate PHT (RR, 2.13; 95%CI, 1.28-3.55; P < .01) were associated with higher unadjusted in-hospital mortality compared with no PHT. Any PHT was associated with a higher unadjusted risk of stroke (RR, 1.64; 95%CI, 1.42-1.90; P < .01), acute kidney injury (RR, 2.02; 95%CI, 1.50-2.72; P < .01), prolonged ventilation (RR, 1.62; 95%CI, 1.04-2.52; P = .03), and longer hospital stay (MD, 1.76 days; 95%CI, 0.57-2.95; P < .01). Severe (HR, 2.44; 95%CI, 1.60-3.72; P < .01) but not mild-moderate PHT (HR, 2.25; 95%CI, 0.91-5.59; P = .08) was associated with higher adjusted long-term mortality compared with no PHT. CONCLUSIONS: Patients with severe AS and severe PHT had a significant increase in operative mortality and more than double the risk of long-term mortality following SAVR compared with patients with no PHT. Such patients may benefit from a less invasive transcatheter aortic valve intervention.

Hybrid ablation for atrial fibrillation: the importance of achieving transmurality and lesion validation.

Therapeutic ablation for atrial fibrillation (AF) has evolved significantly with progressive advancements in technology and surgical instruments. With the goal of minimizing surgical morbidity while maintaining the benefits of the traditional Cox-Maze procedure, surgical ablation for AF has undergone significant modifications. Most recently, an increased understanding of substrate complexity, predominantly in patients with persistent or long-standing persistent AF, has led to the development of a synergistic hybrid approach. The hybrid approach attempts to combine the benefits of epicardial ablation and catheter-based endocardial ablation in order to overcome the shortcomings associated with each technique alone. Importantly, the aid of electrophysiological intervention has provided new opportunities for evaluating lesion transmurality both acutely and in a staged approach. Therefore, the hybrid procedure may provide the optimal approach for the surgical treatment of AF, with the potential to tailor procedural treatment according to the patient's specific needs. In this review, we aim to provide an overview of current surgical techniques, including the implications of this novel hybrid approach in the management of AF and improving procedural outcomes. Recent findings from published studies are highlighted with a primary focus on the importance of lesion transmurality and validation in a hybrid setting.

Epicardial Electrical Activation During Atrial Fibrillation: Looking at the Other Side of the Coin.

High-definition mapping of atrial fibrillation is most commonly performed from the endocardial surface. This report describes an example of a case in which combined mapping of the endocardium and epicardium of the left atrium demonstrated electrical dissociation between the 2 surfaces and implies that endocardial mapping alone may not provide sufficient information. (Level of Difficulty: Advanced.).

Impact of body mass index on the outcome of catheter ablation of atrial fibrillation.

OBJECTIVES: The association between obesity and atrial fibrillation (AF) is well-established. We aimed to evaluate the impact of index body mass index (BMI) on AF recurrence at 12 months following catheter ablation using propensity-weighted analysis. In addition, periprocedural complications and fluoroscopy details were examined to assess overall safety in relationship to increasing BMI ranges. METHODS: Baseline, periprocedural and follow-up data were collected on consecutive patients scheduled for AF ablation. There were no specific exclusion criteria. Patients were categorised according to baseline BMI in order to assess the outcomes for each category. RESULTS: Among 3333 patients, 728 (21.8%) were classified as normal (BMI <25.0 kg/m2), 1537 (46.1%) as overweight (BMI 25.5-29.0 kg/m2) and 1068 (32.0%) as obese (BMI ≥30.0 kg/m2). Procedural duration and radiation dose were higher for overweight and obese patients compared with those with a normal BMI (p=0.002 and p<0.001, respectively). An index BMI ≥30 kg/m2 led to a 1.2-fold increased likelihood of experiencing recurrent AF at 12-months follow-up as compared with overweight patients (HR 1.223; 95% CI 1.047 to 1.429; p=0.011), while no significant correlation was found between overweight and normal BMI groups (HR 0.954; 95% CI 0.798 to 1.140; p=0.605) and obese versus normal BMI (HR 1.16; 95% CI 0.965 to 1.412; p=0.112). CONCLUSIONS: Patients with a baseline BMI ≥30 kg/m2 have a higher recurrence rate of AF following catheter ablation and therefore lifestyle modification to target obesity preprocedure should be considered in these patients.

Magna Ease Versus Trifecta Early Hemodynamics: A Systematic Review and Meta-analysis.

OBJECTIVE: This meta-analysis compares the early echocardiographic outcomes of aortic valve replacement using the two most commonly implanted stented bioprostheses. METHODS: We searched MEDLINE and EMBASE databases until 2017 for studies comparing Magna or Magna Ease (Edwards Lifesciences, Irvine, CA USA) versus Trifecta (St Jude Medical, St. Paul, MN USA) aortic bioprosthetic valves. A random-effects meta-analysis was performed for the primary outcome of mean gradient on echocardiography and secondary outcomes of effective orifice area, indexed effective orifice area, and in-hospital mortality. RESULTS: There were two randomized controlled trial, three matched, and six unmatched retrospective observational studies with 2119 patients [median reported follow-up = 6 months (interquartile range = 6 to 12)]. The Magna/Magna Ease valve was associated with higher early mean gradient (mean difference = 4.09, 95% confidence interval = 3.48 to 4.69, P < 0.0001) and smaller effective orifice area (mean difference = 0.30, 95% confidence interval = -0.38 to -0.22, P < 0.0001). There were no differences in 30-day mortality between Magna/Magna Ease and Trifecta (relative risk = 1.01, 95% confidence interval = 0.41 to 2.50, P = 1.0). CONCLUSIONS: Trifecta may offer a small hemodynamic advantage compared with the Magna/Magna Ease valve with no differences in early mortality. Long-term follow-up is required to determine whether these differences persist and translate into differences in clinical outcomes.

What is the state of hybrid coronary revascularization in 2018?

PURPOSE OF REVIEW: Hybrid coronary revascularization (HCR) combines minimally invasive surgical bypass with percutaneous coronary intervention (PCI) using drug-eluting stents, the goal being to leverage the strengths of each approach. Here we provide an update on HCR from the past 12 months. RECENT FINDINGS: HCR represents a minority of surgical revascularization cases from a small number of highly experienced surgical centers. Most single-center observational series show no differences in major cardiovascular outcomes comparing HCR and coronary artery bypass graft (CABG) or HCR and PCI. The 5-year results of the first randomized study comparing HCR to CABG reported no difference in all-cause mortality, myocardial infarction, and repeat revascularization. Comparing HCR with multivessel PCI, a large, prospective observational study reported no difference in risk-adjusted major adverse cardiovascular events at 12 months. The Hybrid Coronary Revascularization Trial is an international, multicenter, randomized controlled trial to compare HCR versus PCI for patients with proximal left anterior descending disease or left main disease. This trial is currently recruiting patients. SUMMARY: HCR is a potentially attractive alternative to both surgical revascularization and multivessel PCI when performed in experienced centers for highly selected patients. The results of a large, multicenter, prospective trial will provide greater clarity on the clinical role and optimal coronary anatomy for this third revascularization option.