Atrial septal defect in adulthood: a new paradigm for congenital heart disease.

Atrial septal defects (ASDs) represent the most common congenital heart defect diagnosed in adulthood. Although considered a simple defect, challenges in optimal diagnostic and treatment options still exist due to great heterogeneity in terms of anatomy and time-related complications primarily arrhythmias, thromboembolism, right heart failure and, in a subset of patients, pulmonary arterial hypertension (PAH). Atrial septal defects call for tertiary expertise where all options may be considered, namely catheter vs. surgical closure, consideration of pre-closure ablation for patients with atrial tachycardia and suitability for closure or/and targeted therapy for patients with PAH. This review serves to update the clinician on the latest evidence, the nuances of optimal diagnostics, treatment options, and long-term follow-up care for patients with an ASD.

Religion and spirituality as predictors of patient-reported outcomes in adults with congenital heart disease around the globe.

AIMS: Religion and spirituality can be resources for internal strength and resilience, and may assist with managing life's challenges. Prior studies have been undertaken primarily in countries with high proportions of religious/spiritual people. We investigated (i) whether being religious/spiritual is an independent predictor of patient-reported outcomes (PROs) in a large international sample of adults with congenital heart disease, (ii) whether the individual level of importance of religion/spirituality is an independent predictor for PROs, and (iii) if these relationships are moderated by the degree to which the respective countries are religious or secular. METHODS AND RESULTS: APPROACH-IS was a cross-sectional study, in which 4028 patients from 15 countries were enrolled. Patients completed questionnaires to measure perceived health status; psychological functioning; health behaviors; and quality of life. Religion/spirituality was measured using three questions: Do you consider yourself religious or spiritual?; How important is religion, spirituality, or faith in your life?; and If religious, to what religion do you belong?. The country level of religiosity/secularity was appraised using data from the Gallup Poll 2005-2009. General linear mixed models, adjusting for patient characteristics and country differences were applied. Overall, 49.2% of patients considered themselves to be religious/spiritual. Being religious/spiritual and considering religion/spirituality as important in one's life was positively associated with quality of life, satisfaction with life and health behaviors. However, among patients living in more secular countries, religion/spirituality was negatively associated with physical and mental health. CONCLUSION: Religiosity/spirituality is an independent predictor for some PROs, but has differential impact across countries.

Reducing radiation exposure during procedures performed in the electrophysiology laboratory.

INTRODUCTION: Expert societies recently published strong recommendations to reduce the exposure of patients and staff to ionizing radiation (IR) during interventional and electrophysiology (EP) procedures. However, adherence to these guidelines remains difficult and the impact of implementing such recommendations is poorly characterized. METHODS AND RESULTS: We conducted a single-center cohort study to quantify radiation exposure over time in three EP laboratories at the Montreal Heart Institute during 5,546 consecutive procedures from 2012 to 2015 by 11 primary operators. Overall, 2,618 (47.2%) procedures were catheter-based and 2,928 (52.8%) were device interventions. Interventions to reduce radiation exposure included educational initiatives to raise awareness (i.e., limiting cine acquisition, patient position, table height), slower frame rate, lower radiation dose per pulse, collimation, and integration with 3-D mapping systems and/or MediGuide technology. An 85% reduction in IR exposure was observed from 2012 to 2015, with the mean dose-area-product (DAP) decreasing from 7.65 ± 0.05 Gy·cm2 to 1.15 ± 0.04 Gy·cm2 (P < 0.001). This was true for catheter-based procedures (mean DAP 16.99 ± 0.08 to 2.00 ± 0.06 Gy·cm2 , P < 0.001) and device interventions (mean DAP 4.18 ± 0.06 to 0.64 ± 0.05 Gy·cm2 , P < 0.001). The median effective dose of IR recorded per quarter by 282 cervical dosimeters on EP staff decreased from 0.57 (IQR 0.18, 1.03) mSv in 2012 to 0.00 (IQR 0.00, 0.19) mSv in 2015, P < 0.001. CONCLUSION: Enforcing good clinical practices with simple measures and low-dose fluoroscopy settings are highly effective in reducing IR exposure in the EP lab. These promising results should encourage other EP labs to adopt similar protective measures.

Predictors of Ventricular Arrhythmias and Sudden Death in a Québec Cohort With Brugada Syndrome.

BACKGROUND: Patients with Brugada syndrome (BrS) are at risk for ventricular arrhythmias (VAs) and sudden death. Identification of high-risk individuals beyond those with syncope or resuscitated sudden death remains a major challenge. METHODS: We assessed the value of clinical, electrophysiological, and electrocardiographic (ECG) features, including depolarization and repolarization metrics, in predicting arrhythmic events and sudden death in consecutive patients with BrS diagnosed between 2002 and 2013 in Quebec, Canada. Qualifying electrocardiograms with the highest type 1 ST-segment elevations were reviewed and analyzed by 2 electrophysiologists who were blinded to clinical history. Survival analyses were adjusted for Firth bias correction and left truncation. RESULTS: A total of 105 patients, 79.8% of whom were men, were diagnosed with BrS at a mean age of 46.2 ± 13.3 years and were followed for 59.6 ± 16.4 months. Ten (9.5%) had a history of cardiac arrest, 37 (35.2%) had syncope, and 7 (6.7%) experienced 20 arrhythmic events during follow-up, all consisting of appropriate ICD therapy (7 antitachycardia pacing; 13 shocks). In multivariate Cox regression analyses, a spontaneous type 1 electrocardiographic (ECG) pattern (hazard ratio [HR], 10.80; 95% confidence interval [CI], 1.03-113.87; P = 0.0476), maximal T peak-end (Tp-e) duration ≥ 100 ms (HR, 29.73; 95% CI, 1.33-666.37; P = 0.0325), and QRS duration in lead V6 > 110 ms (HR, 15.27; 95% CI, 1.07-217.42; P = 0.0443) were independently associated with VAs or aborted sudden cardiac death. CONCLUSIONS: In a multicentre cohort with BrS from Quebec, Canada, VAs and sudden death were independently associated with standard 12-lead ECG features, including a spontaneous type 1 pattern, depolarization (QRS in lead V6), and repolarization (maximal Tp-e duration) criteria.

Five-year outcome of catheter ablation of persistent atrial fibrillation using termination of atrial fibrillation as a procedural endpoint.

BACKGROUND: This study aimed to determine 5-year efficacy of catheter ablation for persistent atrial fibrillation (AF) using AF termination as a procedural end point. METHODS AND RESULTS: One hundred fifty patients (57±10 years) underwent persistent AF ablation using a stepwise ablation approach (pulmonary vein isolation, electrogram-guided, and linear ablation) with the desired procedural end point being AF termination. Repeat ablation was performed for recurrent AF or atrial tachycardia. AF was terminated by ablation in 120 patients (80%). Arrhythmia-free survival rates after a single procedure were 35.3%±3.9%, 28.0%±3.7%, and 16.8%±3.2% at 1, 2, and 5 years, respectively. Arrhythmia-free survival rates after the last procedure (mean 2.1±1.0 procedures) were 89.7%±2.5%, 79.8%±3.4%, and 62.9%±4.5%, at 1, 2, and 5 years, respectively. During a median follow-up of 58 (interquartile range, 43-73) months after the last ablation procedure, 97 of 150 (64.7%) patients remained in sinus rhythm without antiarrhythmic drugs. Another 14 (9.3%) patients maintained sinus rhythm after reinitiation of antiarrhythmic drugs, and an additional 15 (10.0%) patients regressed to paroxysmal recurrences only. Failure to terminate AF during the index procedure (hazard ratio 3.831; 95% confidence interval, 2.070-7.143; P<0.001), left atrial diameter≥50 mm (hazard ratio 2.083; 95% confidence interval, 1.078-4.016; P=0.03), continuous AF duration≥18 months (hazard ratio 1.984; 95% confidence interval, 1.024-3.846; P<0.04), and structural heart disease (hazard ratio 1.874; 95% confidence interval, 1.037-3.388; P=0.04) predicted arrhythmia recurrence. CONCLUSIONS: In patients with persistent AF, an ablation strategy aiming at AF termination is associated with freedom from arrhythmia recurrence in the majority of patients over a 5-year follow-up period. Procedural AF nontermination and specific baseline factors predict long-term outcome after ablation.

New directions in cardiac arrhythmia management: present challenges and future solutions.

Cardiac arrhythmias are a major contributor to population morbidity and mortality. Enormous advances in arrhythmia management have occurred over the 60 years since the founding of the Montreal Heart Institute, but important challenges remain. The purpose of this article is to identify the areas of cardiac arrhythmia therapy that need improvement and to discuss the evolving approaches that promise solutions. Challenges in diagnosis, detection, and risk-stratification include difficulties in separating benign from high-risk syncope and pinpointing the underlying causes, the detection of silent atrial fibrillation in patients at risk of stroke, and inadequate identification of sudden-death risk. Implantable devices are limited by the need for battery and device replacements, device complications like infection and dysfunction, and lead complications like fracture, infection, or displacement. Antiarrhythmic drug therapy, although widely used, is plagued by a very limited range of available agents, supply issues, insufficient efficacy, and significant adverse effect risk. Health economic concerns include the high cost of new technologies, challenges in establishing cost effectiveness, and restrictive practices of government or third-party payers. Major improvements in arrhythmia management can be expected from new discoveries and technological developments in genetics, innovative diagnostic tools for arrhythmia monitoring, imaging and analysis, new approaches to antiarrhythmic drug development, biological therapies, and continuing improvement in implantable device technology like further miniaturization, leadless technology, and use of novel energy sources. As exciting as the developments in arrhythmia management have been in the past, we can look forward to exponential improvement in our ability to manage arrhythmia patients in the near future.

Clinical experience with a novel electromyographic approach to preventing phrenic nerve injury during cryoballoon ablation in atrial fibrillation.

BACKGROUND: Phrenic nerve palsy remains the most frequent complication associated with cryoballoon-based pulmonary vein (PV) isolation. We sought to characterize our experience using a novel monitoring technique for the prevention of phrenic nerve palsy. METHODS AND RESULTS: Two hundred consecutive cryoballoon-based PV isolation procedures between October 2010 and October 2013 were studied. In addition to standard abdominal palpation during right phrenic nerve pacing from the superior vena cava, all patients underwent diaphragmatic electromyographic monitoring using surface electrodes. Cryoablation was terminated on any perceived reduction in diaphragmatic motion or a 30% decrease in the compound motor action potential (CMAP). During right-sided ablation, a ≥30% reduction in CMAP amplitude occurred in 49 patients (24.5%). Diaphragmatic motion decreased in 30 of 49 patients and was preceded by a 30% reduction in CMAP amplitude in all. In 82% of cases, this reduction in CMAP amplitude occurred during right superior PV isolation. The baseline CMAP amplitude was 946.5±609.2 mV and decreased by 13.8±13.8% at the end of application. This decrease was more marked in the 33 PVs with a reduction in diaphragmatic motion than in those without (40.9±15.3% versus 11.3±10.5%; P<0.001). In 3 cases, phrenic nerve palsy persisted beyond the end of the procedure, with all cases recovering within 6 months. Despite the shortened application all veins were isolated. At repeat procedure the right-sided PVs reconnected less frequently than the left-sided PVs in those with phrenic nerve palsy. CONCLUSIONS: Electromyographic phrenic nerve monitoring using the surface CMAP is reliable, easy to perform, and offers an early warning to impending phrenic nerve injury.

The time course of exit and entrance block during cryoballoon pulmonary vein isolation.

AIMS: The dynamic time course of entrance and exit block during pulmonary vein isolation (PVI) is unknown. The purpose of this series was to dynamically evaluate the manifestation of entrance and exit conduction block during simultaneous circumferential PVI. METHODS AND RESULTS: Pacing manoeuvres were performed during cryoballoon ablation of left-sided pulmonary veins (PVs) in 30 consecutive patients with a history of drug-refractory paroxysmal atrial fibrillation. At the onset of ablation continuous pacing was performed from the PV at a cycle length of 600 ms until the appearance of exit block. Once exit block was demonstrated, uninterrupted pacing was immediately transitioned to the distal coronary sinus (CS) catheter and continued at 600 ms throughout the rest of the cryoapplication. The timing of exit block, entrance block, and corresponding cryoballoon temperature were noted for all patients. In the 45 PVs when real-time PV recordings were available during cryothermal ablation, the presence of exit block was reliably demonstrated to precede entrance block (P < 0.0001) by a median of 5 s [interquartile range (IQR) 3, 12; median temperature at isolation -39°C (IQR -30, -45); nadir ablation temperature -53°C (IQR -48, -59)]. In all cases, when uninterrupted pacing was transitioned from the PV to the distal CS, entrance conduction from the left atrium to PV remained intact. CONCLUSION: Circumferential PV ablation results in progressive PVI, beginning with unidirectional exit block, and followed by entrance block. As exit block reliably precedes entrance block, we are able to provide justification for the exclusive use of entrance conduction block as the endpoint of cryoballoon-based PVI.

Diagnostic tools for arrhythmia detection in adults with congenital heart disease and heart failure.

As patients with congenital heart disease age with increasingly complex lesions, heart failure and arrhythmias have emerged as leading sources of morbidity and mortality. The two are intertwined, as one may herald, beget, or aggravate the other. Moreover, arrhythmias in adults with congenital heart disease and heart failure can be poorly tolerated or life threatening. There is, therefore, much interest in promptly and accurately diagnosing arrhythmias and identifying risk factors for sudden death. This article appraises current knowledge regarding diagnostic tools for arrhythmias in adults with congenital heart disease and heart failure and comments on their prognostic value where relevant.

Electrophysiologic therapeutics in heart failure in adult congenital heart disease.

Arrhythmias have long been recognized as a major cause of morbidity and mortality in the adult with congenital heart disease. It is important that the clinician accurately diagnoses these disturbances and is cognizant of the full array of antiarrhythmic agents and devices available to treat these conditions. This review discusses the most common arrhythmias encountered in this population and the therapeutic options available. Specific issues unique to this population are also addressed.

Improved outcome following restoration of sinus rhythm prior to catheter ablation of persistent atrial fibrillation: a comparative multicenter study.

BACKGROUND: Catheter ablation of persistent atrial fibrillation (AF) is associated with longer procedure times and lower long-term success rates than that of paroxysmal AF. OBJECTIVE: To test the hypothesis that restoration/maintenance of sinus rhythm (SR) preablation would facilitate AF termination and improve outcomes in patients with persistent AF. METHODS: We conducted a 2-group cohort study of consecutive patients with persistent AF and SR restored for at least 1 month prior to ablation (SR group; n = 40) and controls matched by age, sex, and AF duration (control group; n = 40). Radiofrequency stepwise catheter ablation was performed in AF for both groups (induced and spontaneous, respectively). Success was defined as freedom from atrial tachyarrhythmia without antiarrhythmic drugs beyond 1 year of follow-up. RESULTS: During the index ablation procedure, AF cycle length was longer in the SR group than in the control group (183 ± 32 ms vs 166 ± 20 ms; P = .06), suggestive of reverse remodeling. In the SR group, AF more frequently terminated during ablation (95.0% vs 77.5%; P <.05) and required less extensive ablation of complex fractionated electrograms (40.0% vs 87.5%; P <.001) and linear lesions (42.5% vs 82.5%; P <.001). Mean procedural (199.8 ± 69.8 minutes vs 283.5 ± 72.3 minutes; P <.001), fluoroscopy (51.0 ± 24.9 minutes vs 96.3 ± 32.1 minutes; P <.001), and radiofrequency energy delivery (47.5 ± 18.9 minutes vs 97.0 ± 30.6 minutes; P <.001) times were shorter in the SR group. Clinical success rates were similar between groups for first (55.0% vs 45.0%; P = .28) and last (80.0% vs 70.0%; P = .28) procedures, during similar follow-up periods (21.1 ± 9.7 months). CONCLUSIONS: Restoration of SR prior to catheter ablation for persistent AF whenever possible decreases the extent of ablation with the same high clinical efficacy.

Electrophysiology and adult congenital heart disease: advances and options.

Although "congenital heart disease" incorporates a broad and diverse spectrum of inborn cardiac disorders, one shared feature is the propensity for cardiac arrhythmias, albeit to varying degrees. The magnitude of this issue is underscored by its high prevalence, major impact on morbidity and disability, considerable consummation of healthcare resources, and loss of life at ages well below normative population values. Moreover, with changing demographics, arrhythmias increasingly afflict the aging and growing population of survivors with congenital heart disease. Nevertheless, the field of cardiac electrophysiology has, auspiciously, greatly matured over the past 2 decades. The fruits of this progress are largely applicable to adults with congenital heart disease. This review focuses on recent advances and emerging therapeutic options that are providing safer solutions and increasing the effectiveness with which arrhythmias may be managed in adults with congenital heart disease, spanning pharmacotherapy to innovative interventions.

Concordance between an electroanatomic mapping system and cardiac MRI in arrhythmogenic right ventricular cardiomyopathy.

A 29-year-old man presenting with syncopal ventricular tachycardia was diagnosed with arrhythmogenic right ventricular (RV) cardiomyopathy. Cardiac magnetic resonance imaging (MRI) revealed an unequivocal dyskinetic segment at the basal portion of the RV lateral free wall. Three-dimensional electroanatomic voltage mapping using the EnSite NavX system recorded a low voltage area corresponding to the diseased portion of the right ventricle identified by MRI. This report describes concordance between cardiac MRI and this novel mapping system in arrhythmogenic RV cardiomyopathy.

Angiotensin receptor blockade and exercise capacity in adults with systemic right ventricles: a multicenter, randomized, placebo-controlled clinical trial.

BACKGROUND: Pharmacological blockade of the renin-angiotensin system improves exercise tolerance in patients with left ventricular dysfunction, yet its impact on patients with systemic right ventricles (RVs) remains unknown. METHODS AND RESULTS: A multicenter, randomized, double-blind, placebo-controlled, crossover clinical trial was performed to assess the effects of losartan on exercise capacity and neurohormonal levels in patients with systemic RVs. Of 29 patients studied (age, 30.3+/-10.9 years), 21 had transposition of the great arteries with a Mustard baffle, and 8 had congenitally corrected transposition of the great arteries. Baseline values were as follows: VO2max, 29.8+/-5.6 mL.kg(-1).min(-1) (73.5+/-12.9% predicted value); RV ejection fraction, 41.6+/-9.3%; N-terminal pro brain natriuretic peptide (NT-proBNP), 257.7+/-243.4 pg/mL (normal <125 pg/mL); and angiotensin II, 5.7+/-4.9 pg/mL (normal <5.0 pg/mL). Comparing losartan to placebo showed no differences in VO2max (29.9+/-5.4 versus 29.4+/-6.2 mL.kg(-1).min(-1); P=0.43), exercise duration (632.3+/-123.0 versus 629.9+/-140.7 seconds; P=0.76), and NT-proBNP levels (201.2+/-267.8 versus 229.7+/-291.5 pg/mL; P=0.10), despite a trend toward increased angiotensin II levels (15.2+/-13.8 versus 8.8+/-12.5 pg/mL; P=0.08). CONCLUSIONS: In adults with systemic RVs, losartan did not improve exercise capacity or reduce NT-proBNP levels. Minimal baseline activation of the renin-angiotensin system may explain this lack of benefit and imply an alternative pathophysiological mechanism for the progressive ventricular dysfunction and impaired exercise capacity observed in such patients.

Atrial fibrillation: basic and clinical research at the Montreal Heart Institute.

The present article reviews pertinent contributions from the Montreal Heart Institute, Montreal, Quebec, to the understanding of the mechanisms and treatment of atrial fibrillation. The article discusses the usefulness of anticoagulant therapy, antiarrhythmic drug therapy for sinus rhythm maintenance, the electrophysiological basis of atrial fibrillation and the investigation of new energy sources for catheter ablation. Future directions at the Montreal Heart Institute are also briefly addressed.