Cardiovascular Outcomes in Fontan Patients With Right vs Left Univentricular Morphology: A Multicenter Study.

Background: There is a paucity of data on long-term outcomes after Fontan palliation in patients with a dominant morphological univentricular right (uRV) vs left (uLV) ventricle. Objectives: The purpose of this study was to compare the incidence of atrial arrhythmias, thromboembolic events, cardiac transplantation, and death following Fontan palliation in patients with uRV vs uLV. Methods: The Alliance for Adult Research in Congenital Cardiology conducted a multicenter retrospective cohort study on patients with total cavopulmonary connection Fontan palliation across 12 centers in North America. All components of the composite outcome, that is, atrial arrhythmias, thromboembolic events, cardiac transplantation, and death, were reviewed and classified by a blinded adjudicating committee. Time-to-event analyses were performed that accounted for competing risks. Results: A total of 384 patients were followed for 10.5 ± 5.9 years. The composite outcome occurred in 3.7 vs 1.7 cases per 100 person-years for uRV (N = 171) vs uLV (N = 213), respectively (P < 0.001). In multivariable analyses, uRV conferred a >2-fold higher risk of the composite outcome (HR: 2.17, 95% CI: 1.45-3.45, P < 0.001). In secondary analyses of components of the primary outcome, uRV was significantly associated with a greater risk of cardiac transplantation or death (HR: 9.09, 95% CI: 2.17-38.46, P < 0.001) and atrial arrhythmias (HR: 2.17, 95% CI: 1.20-4.00, P = 0.010) but not thromboembolic events (HR: 1.64, 95% CI: 0.86-3.16, P = 0.131). Conclusions: Fontan patients with uRV vs uLV morphology have a higher incidence of adverse cardiovascular events, including atrial arrhythmia, cardiac transplantation, and all-cause mortality.

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.

Association of Atrial Fibrillation Burden With Health-Related Quality of Life After Atrial Fibrillation Ablation: Substudy of the Cryoballoon vs Contact-Force Atrial Fibrillation Ablation (CIRCA-DOSE) Randomized Clinical Trial.

Importance: Patients with atrial fibrillation (AF) have impaired health-related quality of life primarily owing to symptoms related to AF episodes; however, quality of life can be influenced by AF therapies, AF complications, the frequency of follow-up visits and hospitalizations, illness perceptions, and patient factors, such as anxiety or depression. Objective: To determine the association between change in AF burden and quality of life in the year following ablation. Design, Setting, and Participants: The current study is a secondary analysis of a prospective, parallel-group, multicenter, single-masked randomized clinical trial (Cryoballoon vs Irrigated Radiofrequency Catheter Ablation: Double Short vs Standard Exposure Duration [CIRCA-DOSE] study), which took place at 8 Canadian centers. Between September 2014 and July 2017, 346 patients older than 18 years with symptomatic, primarily low-burden AF refractory to antiarrhythmic therapy referred for first catheter ablation were enrolled. All patients received an implantable cardiac monitor at least 30 days before ablation and were followed up with up to December 2018. Data were analyzed from April 2020 to June 2021. Interventions: Patients were randomized 1:1:1 to contact force-guided radiofrequency ablation, 4-minute cryoballoon ablation, or 2-minute cryoballoon ablation. The exposure in the present analysis is the absolute difference in AF burden prior to ablation and 12 months following ablation, as evaluated by the Atrial Fibrillation Effect on Quality of Life (AFEQT) Score. Main Outcomes and Measures: Absolute difference in quality of life from baseline to 12 months postablation. Results: Of 346 included patients, 231 (66.7%) were male, and the median (interquartile range) age was 60 (52-66) years. A total of 328 patients (94.8%) had paroxysmal AF. The median (interquartile range) preablation AF burden was 2.0% (0.1-11.9), and the AF burden decreased to 0% at 12 months postablation. At 12 months, a 1-point improvement in AFEQT score was observed for every absolute reduction in daily AF burden of 15.8 minutes (95% CI, 7.2-24.4; P < .001), or every 0.63% (95% CI, 0.30-0.95; P < .001) reduction in relative AF burden from baseline. Conclusions and Relevance: In patients with primarily low-burden paroxysmal AF, the reduction in AF burden following ablation may be associated with a clinically meaningful improvement in quality of life. Trial Registration: ClinicalTrials.gov Identifier: NCT01913522.

Anticoagulant Use and the Risk of Thromboembolism and Bleeding in Postoperative Atrial Fibrillation After Noncardiac Surgery.

BACKGROUND: An effective and safe oral anticoagulation (OAC) strategy for patients with new postoperative AF (POAF) after noncardiac surgery remains unclear. We aimed to determine the association between OAC use and 1) thromboembolic events and 2) major bleeding in patients with POAF after noncardiac surgery. METHODS: A retrospective cohort (1999-2015) was used to identify patients with new POAF after inpatient noncardiac surgery. Initiation of OAC was defined as prescription of an OAC within 30 days following hospital discharge. Times to first hospital admission or emergency department visit for a thromboembolic or major bleeding event were compared using Cox proportional hazards models. RESULTS: We identified 22,007 patients with new POAF after inpatient noncardiac surgery. The majority of patients had intermediate (CHA2DS2-VASc 2-3: 45%) to high (CHA2DS2-VASc ≥ 4: 42%) thromboembolic risk. During a mean follow-up of 4 years, a total of 1099 (5%) thromboembolic and 3250 (15%) bleeding events occurred. Compared with patients not on anticoagulation, anticoagulation did not reduce the risk for thromboembolic events (adjusted hazard ratio [aHR] 0.89, 95% CI 0.73-1.07). In patients initiated on anticoagulation, there was an association with a higher risk for major bleeding (aHR 1.14, 95% CI 1.04-1.25). CONCLUSIONS: In patients with new POAF after noncardiac surgery, anticoagulation was not associated with a reduction in long-term thromboembolic events; however, this was accompanied by an overall increased risk for major bleeding. Future prospective clinical studies are needed to better address the role for anticoagulation therapy in the setting of POAF after noncardiac surgery to understand the efficacy and safety of treatment.

Pulmonary Vein Stenosis After Atrial Fibrillation Ablation: Insights From the ADVICE Trial.

BACKGROUND: Pulmonary vein (PV) stenosis is a complication of atrial fibrillation (AF) ablation. The incidence of PV stenosis after routine post-ablation imaging remains unclear and is limited to single-centre studies. Our objective was to determine the incidence and predictors of PV stenosis following circumferential radiofrequency ablation in the multicentre Adenosine Following Pulmonary Vein Isolation to Target Dormant Conduction Elimination (ADVICE) trial. METHODS: Patients with symptomatic AF underwent circumferential radiofrequency ablation in one of 13 trial centres. Computed tomographic (CTA) or magnetic resonance (MRA) angiography was performed before ablation and 90 days after ablation. Two blinded reviewers measured PV diameters and areas. PVs with stenosis were classified as severe (> 70%), moderate (50%-70%), or mild (< 50%). Predictors of PV stenosis were identified by means of multivariable logistic regression. RESULTS: A total of 197 patients (median age 59.5 years, 29.4% women) were included in this substudy. PV stenosis was identified in 41 patients (20.8%) and 47 (8.2%) of 573 ablated PVs. PV stenosis was classified as mild in 42 PVs (7.3%) and moderate in 5 PVs (0.9%). No PVs had severe stenosis. Both cross-sectional area and diameter yielded similar classifications for severity of PV stenosis. Diabetes was associated with a statistically significant increased risk of PV stenosis (OR 4.91, 95% CI 1.45-16.66). CONCLUSIONS: In the first systematic multicentre evaluation of post-ablation PV stenosis, no patient acquired severe PV stenosis. Although the results are encouraging for the safety of AF ablation, 20.8% of patients had mild or moderate PV stenosis, in which the long-term effects are unknown.

The use of adenosine to identify dormant conduction after accessory pathway ablation: a single center experience and literature review.

INTRODUCTION: Atrio-ventricular reentrant tachycardias (AVRT) represent around 40 percent of supraventricular tachycardias. After ablation, recurrence rates are around 10 percent. Adenosine has been described as a useful tool to assess presence of dormant conduction and predict recurrence after apparently successful ablation. We reviewed the patients of our service and assessed the role of adenosine in predicting dormant conduction and factors that could influence recurrence rates. METHODS: We retrospectively reviewed electrophysiologic studies and medical charts of 65 patients who had AVRT ablation and had adenosine used to assess dormant conduction at a single quaternary center between 2011 and 2015. Dormant conduction was defined as transient recovery of the preexcitation (for pathways with antegrade conduction) or return of the retrograde conduction through an apparently successfully ablated concealed accessory pathway (AP). RESULTS: One patient was found to have dormant conduction (1.5%) with early recurrence that was not further ablated due to the difficult location of the AP. The overall recurrence rate was 4.6%. General features like location of AP's, their properties, ablation times and technique were assessed. CONCLUSION: Similar to its use in identifying other arrhythmias, adenosine may be useful in identifying dormant conduction for further ablation during initial ablation of an accessory pathway; however, the absence of dormant conduction on adenosine testing does not reliably predict non-recurrence. The low recurrence rates in our service may be related to the frequent use of irrigated tip catheters, 3D mapping and long average ablation time over the successful site of ablation.

Long-term Follow-up of Coronary Artery Bypass Patients With Preoperative and New Postoperative Native Coronary Artery Chronic Total Occlusion.

BACKGROUND: Chronic total occlusions (CTOs) of native coronary arteries are a frequent finding among patients who are referred for surgical revascularization with coronary artery bypass grafting (CABG). The long-term clinical significance of native coronary artery CTO identified at baseline and 1 year after CABG is unknown. METHODS: All patients who underwent 1-year follow-up angiography as part of the multicentre Radial Artery Patency Study (RAPS) were assessed for late clinical events. RESULTS: At a mean follow-up of 7.3 ± 2.9 years, the study group of 388 patients had the following outcomes: 39 (10%) deaths, 6 (1.5%) cases of nonfatal myocardial infarction, and 19 (4.9%) cases of percutaneous coronary intervention (PCI). CTO of ≥ 1 native coronary artery in the baseline preoperative coronary angiogram was demonstrated in 240 (61.9%) patients. The composite of all-cause death, nonfatal myocardial infarction, and PCI occurred significantly more often in patients with at least 1 preoperative CTO than in patients without a preoperative CTO (20% vs 11%; P = 0.048). A new native coronary artery CTO 1 year after surgery occurred in 169 (43.6%) patients. The composite of all-cause death, nonfatal myocardial infarction, and PCI occurred significantly more often in patients with a new CTO 1 year after CABG compared with those without a new CTO (21.3% vs 12.8%; P = 0.028). CONCLUSIONS: In patients undergoing CABG, both preoperative CTOs and new CTOs that develop 1 year after surgery are associated with adverse long-term clinical outcomes.

Native coronary artery patency after coronary artery bypass surgery.

OBJECTIVES: The aim of the study was to determine native coronary artery patency 1 year after coronary artery bypass grafting and to identify clinical and angiographic predictors for the development of a chronic total occlusion (CTO). BACKGROUND: In contrast to the large body of information regarding graft patency, data regarding atherosclerosis progression and vessel patency in surgically bypassed native coronary arteries are less clear. METHODS: Of the 440 patients who underwent 1-year follow-up angiography as part of the multicenter RAPS (Radial Artery Patency Study), included in our study were 388 patients (88%) for whom angiograms were available for review. Angiograms were reviewed for native coronary artery patency in an independent blinded manner. RESULTS: On the pre-operative angiogram, CTO of at least 1 native coronary vessel was demonstrated in 240 patients (61.9%) having 305 occluded vessels. At 1 year after coronary artery bypass grafting, at least 1 new native coronary artery CTO occurred in 169 patients (43.6%). In 7.5% of patients, the native artery and the graft supplying that territory were both occluded. A new CTO was almost 5 times more likely to occur in coronary vessels with a pre-operative proximal stenosis >90% compared with vessels with proximal stenosis <90% (45.5% vs. 9.5%, respectively, p < 0.001). Patients with a new CTO had significantly more baseline Canadian Cardiovascular Society class 4 angina compared with patients without a new CTO. A new CTO was less likely to occur in the left anterior descending artery (18.4%), supplied by the left internal thoracic artery. When comparing radial artery and saphenous vein grafts, neither the type of graft nor graft patency had any association with native coronary artery occlusion. CONCLUSIONS: CTO of surgically bypassed coronary arteries 1 year after coronary artery bypass grafting is extremely common.

Use of a noninvasive continuous monitoring device in the management of atrial fibrillation: a pilot study.

BACKGROUND: Outpatient ambulatory cardiac rhythm monitoring is a routine part of the management of patients with paroxysmal atrial fibrillation (AF). Current systems are limited by patient convenience and practicality. METHODS: We compared the Zio(®) Patch, a single-use, noninvasive waterproof long-term continuous monitoring patch, with a 24-hour Holter monitor in 74 consecutive patients with paroxysmal AF referred for Holter monitoring for detection of arrhythmias. RESULTS: The Zio(®) Patch was well tolerated, with a mean monitoring period of 10.8 ± 2.8 days (range 4-14 days). Over a 24-hour period, there was excellent agreement between the Zio(®) Patch and Holter for identifying AF events and estimating AF burden. Although there was no difference in AF burden estimated by the Zio(®) Patch and the Holter monitor, AF events were identified in 18 additional individuals, and the documented pattern of AF (persistent or paroxysmal) changed in 21 patients after Zio(®) Patch monitoring. Other clinically relevant cardiac events recorded on the Zio(®) Patch after the first 24 hours of monitoring, including symptomatic ventricular pauses, prompted referrals for pacemaker placement or changes in medications. As a result of the findings from the Zio(®) Patch, 28.4% of patients had a change in their clinical management. CONCLUSIONS: The Zio(®) Patch was well tolerated, and allowed significantly longer continuous monitoring than a Holter, resulting in an improvement in clinical accuracy, the detection of potentially malignant arrhythmias, and a meaningful change in clinical management. Further studies are necessary to examine the long-term impact of the use of the Zio(®) Patch in AF management.

Statin therapy prevents expansive remodeling in venous bypass grafts.

BACKGROUND: Venous grafts (VG) have high failure rates by 10 years in aortocoronary bypass surgery. We have previously shown that expansive remodeling followed by increased LDL retention are early atherosclerotic changes in experimental VG placed in the arterial circulation. The objective of this study was to determine whether statin therapy prevents these expansive remodeling changes. METHODS AND RESULTS: Reversed jugular vein-to-common carotid artery interposition graft was constructed in 27 cholesterol-fed (0.5%) rabbits. Rabbits were randomized either to control or atorvastatin (5 mg/kg/day) groups, starting two weeks prior to vein graft implantation and continuing until sacrifice at 1 or 12 weeks post-surgery. Ultrasound measurements of arterial luminal cross-sectional area (CSA) were done at day 3 and at 4, 8 and 12 weeks post-surgery. Histomorphometric measurements were performed following sacrifice at 12 weeks. Atorvastatin treatment significantly decreased total plasma cholesterol levels at 4, 8 and 12 weeks (12 weeks: 6.7 ± 4.2 mmol/L versus control 38.7 ± 10.6 mmol/L, p<0.0002). Atorvastatin significantly reduced expansive remodeling at 4, 8 and 12 weeks (lumen CSA: 44.6 ± 6.6 mm(2) versus control 77.6 ± 10.7 mm(2), p<0.0001). Intimal CSA by histomorphometry was also significantly reduced by atorvastatin at 12 weeks (5.59 ± 2.19 mm(2) versus control 9.57 ± 2.43 mm(2), p<0.01). VG macrophage infiltration, MMP-2 activity and metalloelastase activity were reduced in the atorvastatin treated group. CONCLUSION: Atorvastatin inhibits both expansive remodeling and intimal hyperplasia in arterialized VG, likely through inhibition of macrophage infiltration and reduction of tissue proteolytic activity. The mechanism proposed above may be important for preventing VG atherosclerosis and late VG failure.

Current perspectives on coronary chronic total occlusions: the Canadian Multicenter Chronic Total Occlusions Registry.

OBJECTIVES: The purpose of this study was to determine the prevalence, clinical characteristics, and management of coronary chronic total occlusions (CTOs) in current practice. BACKGROUND: There is little evidence in contemporary literature concerning the prevalence, clinical characteristics, and treatment decisions regarding patients who have coronary CTOs identified during coronary angiography. METHODS: Consecutive patients undergoing nonurgent coronary angiography with CTO were prospectively identified at 3 Canadian sites from April 2008 to July 2009. Patients with previous coronary artery bypass graft surgery or presenting with acute ST-segment elevation myocardial infarction were excluded. Detailed baseline clinical, angiographic, electrocardiographic, and revascularization data were collected. RESULTS: Chronic total occlusions were identified in 1,697 (18.4%) patients with significant coronary artery disease (>50% stenosis in ≥1 coronary artery) who were undergoing nonemergent angiography. Previous history of myocardial infarction was documented in 40% of study patients, with electrocardiographic evidence of Q waves corresponding to the CTO artery territory in only 26% of cases. Left ventricular function was normal in >50% of patients with CTO. Half the CTOs were located in the right coronary artery. Almost half the patients with CTO were treated medically, and 25% underwent coronary artery bypass graft surgery (CTO bypassed in 88%). Percutaneous coronary intervention was done in 30% of patients, although CTO lesions were attempted in only 10% (with 70% success rate). CONCLUSIONS: Chronic total occlusions are common in contemporary catheterization laboratory practice. Prospective studies are needed to ascertain the benefits of treatment strategies of these complex patients.