Cryoballoon or Radiofrequency Ablation for Atrial Fibrillation Assessed by Continuous Monitoring: A Randomized Clinical Trial.

BACKGROUND: Advanced generation ablation technologies have been developed to achieve more effective pulmonary vein isolation (PVI) and minimize arrhythmia recurrence after atrial fibrillation (AF) ablation. METHODS: We randomly assigned 346 patients with drug-refractory paroxysmal AF to contact force-guided radiofrequency ablation (CF-RF; n=115), 4-minute cryoballoon ablation (Cryo-4; n=115), or 2-minute cryoballoon ablation (Cryo-2; n=116). Follow-up was 12 months. The primary outcome was time to first documented recurrence of symptomatic or asymptomatic atrial tachyarrhythmia (AF, atrial flutter, or atrial tachycardia) between days 91 and 365 after ablation or a repeat ablation procedure at any time. Secondary end points included freedom from symptomatic arrhythmia and AF burden. All patients received an implantable loop recorder. RESULTS: One-year freedom from atrial tachyarrhythmia defined by continuous rhythm monitoring was 53.9%, 52.2%, and 51.7% with CF-RF, Cryo-4, and Cryo-2, respectively (P=0.87). One-year freedom from symptomatic atrial tachyarrhythmia defined by continuous rhythm monitoring was 79.1%, 78.2%, and 73.3% with CF-RF, Cryo-4, and Cryo-2, respectively (P=0.26). Compared with the monitoring period before ablation, AF burden was reduced by a median of 99.3% (interquartile range, 67.8%-100.0%) with CF-RF, 99.9% (interquartile range, 65.3%-100.0%) with Cryo-4, and 98.4% (interquartile range, 56.2%-100.0%) with Cryo-2 (P=0.36). Serious adverse events occurred in 3 patients (2.6%) in the CF-RF group, 6 patients (5.3%) in the Cryo-4 group, and 7 patients (6.0%) in the Cryo-2 group, with no significant difference between groups (P=0.24). The CF-RF group had a significantly longer procedure duration but significantly shorter fluoroscopy exposure (P<0.001 vs cryoballoon groups). CONCLUSIONS: In this multicenter, randomized, single-blinded trial, CF-RF and 2 different regimens of cryoballoon ablation resulted in no difference in 1-year efficacy, which was 53% by time to first recurrence but >98% burden reduction as assessed by continuous cardiac rhythm monitoring. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01913522.

Clinical assessment of AF pattern is poorly correlated with AF burden and post ablation outcomes: A CIRCA-DOSE sub-study.

BACKGROUND: Contemporary guidelines recommend that atrial fibrillation (AF) be classified into paroxysmal and persistent AF based on clinical assessment, with these categorizations forming the basis of therapeutic recommendations. While pragmatic, clinical assessment may introduce misclassification errors, which may impact treatment decisions. We sought to determine the relationship between AF classification, baseline AF burden, and post-ablation arrhythmia outcomes. DESIGN: The current study is a sub-analysis of a prospective, parallel-group, multicenter, single-blinded randomized clinical trial. All 346 patients enrolled in CIRCA-DOSE received an implantable cardiac monitor a median of 72 days prior to ablation. AF was classified as low burden paroxysmal, high burden paroxysmal, or persistent based on clinical assessment prior to device implantation. Prior to ablation patients were re-classified using the same definitions based on device monitoring data. Correlation between classifications, AF burden, and post-ablation arrhythmia outcomes were assessed. RESULTS: There was poor agreement between clinical and device-based AF classification (Cohen's kappa: 0.192). AF classification derived from pre-ablation continuous monitoring reflected baseline and post-ablation AF burden with greater accuracy and with less overlap between the AF classes (P < 0.01 for all categorical comparisons). Patients objectively classified as "Low Burden" paroxysmal by continuous monitoring data had significantly greater freedom from recurrent AF/AT/AFL compared to those classified as "High Burden" paroxysmal (hazard ratio [HR] 0.57 for AF/AT/AFL recurrence) or persistent AF (HR 0.19 for AF/AT/AFL recurrence). CONCLUSIONS: Classification of AF pattern based on pre-ablation continuous cardiac rhythm monitoring better predicted AF burden and freedom from recurrent AF post ablation. Despite the use of standardized definitions, classification of AF based on clinical assessment did not predict baseline AF burden, post ablation AF burden, or freedom from recurrent AF post ablation. TRIAL REGISTRATION: ClinicalTrials.govNCT01913522.

A cracking complication: Displacement of existing clavicle fracture complicating subcutaneous implantable cardioverter defibrillator implantation.

An 18 year old male with an incompletely healed clavicle fracture presented with unexplained syncope. Subsequent investigations were consistent with a diagnosis of arrhythmogenic right ventricular cardiomyopathy (ARVC). A subcutaneous implantable cardioverter-defibrillator (S-ICD) was successfully implanted and defibrillation threshold (DFT) testing performed as per standard protocol. Shortly following the procedure, the patient complained of pain and swelling over the left clavicle. A radiograph revealed aggravation and displacement of the underlying clavicle fracture. Surgical reduction and internal fixation was performed one week later.

Inadvertent Removal of a Right Ventricular Pacemaker Lead by a Knotted Transvenous Pacing Wire.

We report an unusual complication of permanent pacemaker (PPM) implantation in a patient with a temporary transvenous pacemaker (TVP) in situ, in which the TVP lead formed a knot around the newly-placed right ventricular (RV) lead, complicating TVP removal. The case underscores the fact that suboptimal TVP lead placement, such as looping in the RV, can result in complications during implantation of a permanent pacemaker. HOW TO CITE THIS ARTICLE: Wiens EJ, Seifer CM et al. Inadvertent Removal of a Right Ventricular Pacemaker Lead by a Knotted Transvenous Pacing Wire. Indian J of Crit Care Med 2019;23(2):102-103.

Permanent Pacemaker-Mediated Exertional Hypoxemia in a Patient With Ebstein Anomaly.

Patients with Ebstein anomaly are known to have a higher incidence of interatrial communications and shunting of blood and its components through, mainly due to either streaming of tricuspid regurgitation or due to elevated right atrial pressure. Here we describe a case where permanent pacemaker lead kept a patent foramen ovale open leading to right-to-left shunting of blood and exertional hypoxemia. This is the first such case report in the published literature.

Navigating the Landscape of Medical Device Advisories: A Special Report From the Canadian Heart Rhythm Society Device Advisory Committee.

Cardiac implantable electronic devices (CIEDs) are often important for regulating cardiac rate and rhythm. Pacemakers and defibrillators are among the top 10 most implanted medical devices, with > 1.5 million devices implanted annually. Although millions of patients have benefited with improved quality of life and survival, CIED systems are becoming increasingly complex and do not always perform according to expectations. Advisory notices communicate important information about the safety and performance of a medical device to health care providers and patients. Medical device recalls are common, with > 35 unique device recalls in the past 5 years. From an ethical standpoint, CIED recalls highlight a range of considerations including the consent process, duty to report, how best to promote autonomous decision-making, trust in the health care system, as well as disproportionate effects of these considerations on equity-deserving groups. The purpose of the current article is to review and advise regarding the process around medical device advisory and recall, with a specific focus on clinicians caring for patients affected by these devices. We have sought the input of a lawyer, a patient advocacy group, and an ethicist to guide the clinical management of, and communications regarding, device recalls and advisories. Diligent surveillance and a clear, transparent patient consent process regarding these small but potentially serious device anomalies is paramount in ensuring patients believe they are safe and informed. Meaningful patient engagement helps to ensure optimal communication and disclosure mechanisms before implantation and throughout follow-up, accessibility of information in the initial implant and recall action process, and trust in health care systems and providers.

High-impedance alerts with pulse generator-Lead mismatch.

Background: Cardiac Implantable Electronic Devices (CIED) include pulse generators and leads. In some implanting centers, it is a common practice to combine devices with leads from different companies. Case series have reported episodic high-impedance changes in Boston Scientific CIEDs with competitor leads. We investigated the incidence of high-impedance abnormalities in matched versus mismatched Boston Scientific Accolade pacemakers. Methods: A retrospective chart review identified all consecutive Boston Scientific Accolade pacemakers implanted between January 2017 and June 2019 at a Canadian tertiary care center. The primary outcome was the occurrence of transient, high-impedance changes which resulted in a switch to unipolar pacing/sensing in the absence of any other identifiable lead issue. Fisher exact tests (two-tailed, α = .05) were used to compare the incidence of outcomes in matched versus mismatched systems. Results: 514 Boston Scientific Accolade pacemakers were associated with 882 individual leads. The primary outcome occurred with 21 leads (20 Medtronic and 1 Abbott), associated with occasional pacing inhibition, presyncope, and/or early surgical revision. Mismatched lead-device pairs were significantly associated with CIED malfunction compared to matched lead-device pairs (3.3% vs. 0%, p = .0019). The median time from implant to unipolar safety switch was 12.4 months. The median follow-up time was 21.6 months. Conclusion: Use of mismatched leads with a Boston Scientific Accolade device was associated with an increased risk of undesirable changes in sensing polarity with occasional inappropriate pacing inhibition. Awareness of this interaction can allow for the institution of appropriate programming remedies and may increase scrutiny of the use of mismatched CIED systems.

3D Electroanatomic Mapping of an Extreme Oblique Accessory Pathway in Wolff-Parkinson-White Syndrome.

A high-risk left-sided posterolateral manifest accessory pathway (AP) was identified in a 49-year-old man. Two prior ablations had failed. A repeat procedure using 3D electroanatomic mapping demonstrated an extremely oblique AP. The earliest atrial activation site was not amenable to endocardial ablation. The earliest ventricular activation site was identified, demonstrating an AP with an extremely slanted course. Radiofrequency ablation here resulted in sustained bidirectional AP block. In challenging AP ablation cases, recognition of the potential for an oblique AP and the use of electroanatomic mapping may be beneficial.

Une voie accessoire (VA) apparente postéro-latérale gauche à haut risque a été identifiée chez un homme de 49 ans. Deux ablations antérieures avaient échoué. Une procédure répétée utilisant la cartographie électroanatomique 3D a révélé une VA extrêmement oblique. Le site ayant l'activation auriculaire la plus précoce ne se prêtait pas à une ablation endocardique. Le site ayant l'activation ventriculaire la plus précoce a été identifié, montrant une VA avec une trajectoire extrêmement inclinée. L'ablation par radiofréquence a ici entraîné un bloc bidirectionnel soutenu de la VA. Dans les cas difficiles d'ablation de VA, la reconnaissance du potentiel d'une VA oblique et l'utilisation de la cartographie électroanatomique peuvent être bénéfiques.

Quality of Life and Health Care Utilization in the CIRCA-DOSE Study.

OBJECTIVES: This study evaluated the impact of contact force-guided radiofrequency ablation versus cryoballoon ablation on quality of life and health care utilization. BACKGROUND: Traditional outcome parameters, such as arrhythmia-free survival, are insufficient to evaluate the clinical impact of atrial fibrillation (AF), as it fails to the capture patient- and health system-level differences in treatment approaches. METHODS: The CIRCA-DOSE (Cryoballoon Vs. Contact-Force Atrial Fibrillation Ablation) study randomly assigned 346 patients with drug-refractory paroxysmal AF to contact force-guided radiofrequency or cryoballoon ablation. Health-related quality-of-life (HRQOL) was assessed at baseline, and at 6 and 12 months post-ablation using a disease-specific and generic HRQOL instruments. Health care utilization (hospitalization, emergency department visits, and cardioversion) and antiarrhythmic drug use for the 12 months preceding ablation was compared with the 12 months following ablation. RESULTS: Disease-specific and generic HRQOL was moderately to severely impaired at baseline and improved significantly at 6 and 12 months of follow-up (median improvement in AFEQT [Atrial Fibrillation Effect on QualiTy of Life] score 32.4 [interquartile range: 17.7 to 48.9]). When compared with the 12 months pre-ablation, the proportion and absolute number of cardioversions decreased significantly (41.1% vs. 10.1% of patients, 137 vs. 35 events; p < 0.0001). Similar significant reductions in emergency department visits (66.7% vs. 25.1% of patients, 224 vs. 87 events; p < 0.0001), and hospitalizations (25.5% vs. 14.5% of patients, 86 vs. 50 events; p < 0.001) were observed. There were no significant differences between randomized groups. CONCLUSIONS: In this multicenter randomized trial, catheter ablation with advanced-generation technologies resulted in a significant improvement in HRQOL and a significant reduction in health care utilization in the year following AF ablation. (Cryoballoon vs. Irrigated Radiofrequency Catheter Ablation [CIRCA-DOSE]; NCT01913522).

2020 Canadian Cardiovascular Society/Canadian Heart Rhythm Society Position Statement on the Management of Ventricular Tachycardia and Fibrillation in Patients With Structural Heart Disease.

This Canadian Cardiovascular Society position statement is focused on the management of sustained ventricular tachycardia (VT) and ventricular fibrillation (VF) that occurs in patients with structural heart disease (SHD), including previous myocardial infarction, dilated cardiomyopathy, and other forms of nonischemic cardiomyopathy. This patient population is rapidly increasing because of advances in care and improved overall survival of patients with all forms of SHD. In this position statement, the acute and long-term management of VT/VF are outlined, and the many unique aspects of care in this population are emphasized. The initial evaluation, acute therapy, indications for chronic suppressive therapy, choices of chronic suppressive therapy, implantable cardioverter-defibrillator programming, alternative therapies, and psychosocial care are reviewed and recommendations for optimal care are provided. The target audience for this statement includes all health professionals involved in the continuum of care of patients with SHD and VT/VF.

Does this patient with palpitations have a cardiac arrhythmia?

CONTEXT: Many patients have palpitations and seek advice from general practitioners. Differentiating benign causes from those resulting from clinically significant cardiac arrhythmia can be challenging and the clinical examination may aid in this process. OBJECTIVE: To systematically review the accuracy of historical features, physical examination, and cardiac testing for the diagnosis of cardiac arrhythmia in patients with palpitations. Data Source, Study Selection, and DATA EXTRACTION: MEDLINE (1950 to August 25, 2009) and EMBASE (1947 to August 2009) searches of English-language articles that compared clinical features and diagnostic tests in patients with palpitations with a reference standard for cardiac arrhythmia. Of the 277 studies identified by the search strategy, 7 studies were used for accuracy analysis and 16 studies for diagnostic yield analysis. Two authors independently reviewed articles for study data and quality and a third author resolved disagreements. DATA SYNTHESIS: Most data were obtained from single studies with small sample sizes. A known history of cardiac disease (likelihood ratio [LR], 2.03; 95% confidence interval [CI], 1.33-3.11), having palpitations affected by sleeping (LR, 2.29; 95% CI, 1.33-3.94), or while the patient is at work (LR, 2.17; 95% CI, 1.19-3.96) slightly increase the likelihood of a cardiac arrhythmia. A known history of panic disorder (LR, 0.26; 95% CI, 0.07-1.01) or having palpitations lasting less than 5 minutes (LR, 0.38; 95% CI, 0.22-0.63) makes the diagnosis of cardiac arrhythmia slightly less likely. The presence of a regular rapid-pounding sensation in the neck (LR, 177; 95% CI, 25-1251) or visible neck pulsations (LR, 2.68; 95% CI, 1.25-5.78) in association with palpitations increases the likelihood of a specific type of arrhythmia (atrioventricular nodal reentry tachycardia). The absence of a regular rapid-pounding sensation in the neck makes detecting the same arrhythmia less likely (LR, 0.07; 95% CI, 0.03-0.19). No other features significantly alter the probability of clinically significant arrhythmia. Diagnostic tests for prolonged periods of electrocardiographic monitoring vary in their yield depending on the modality used, duration of monitoring, and occurrence of typical symptoms during monitoring. Loop monitors have the highest diagnostic yield (34%-84%) for identifying an arrhythmia. CONCLUSIONS: While the presence of a regular rapid-pounding sensation in the neck or visible neck pulsations associated with palpitations makes the diagnosis of atrioventricular nodal reentry tachycardia likely, the reviewed studies suggest that the clinical examination is not sufficiently accurate to exclude clinically significant arrhythmias in most patients. Thus, prolonged electrocardiographic monitoring with demonstration of symptom-rhythm correlation is required to make the diagnosis of a cardiac arrhythmia for most patients with recurrent palpitations.

An Atypical Case of Takotsubo Cardiomyopathy and Transient Global Amnesia.

Takotsubo cardiomyopathy (TTC) may clinically mimic an acute coronary syndrome and is most often associated with an acute stressor. In this case report, we describe an atypical case of TTC triggered by multiple subacute stressors rather than 1 acute stressor. We also report TTC and transient global amnesia occurring concurrently. This case highlights that TTC can present without a typical stressor and should nonetheless by considered in the appropriate clinical context. Concomitant presentation with transient global amnesia is uncommon, but may result from the 2 conditions potentially sharing an underlying etiology.

La cardiomyopathie de Takotsubo (CTT) peut ressembler sur le plan clinique à un syndrome coronarien aigu et est plus souvent associée à un facteur de stress aigu. Dans ce rapport de cas, nous décrivons un cas atypique de CTT provoquée par de nombreux facteurs de stress subaigu plutôt que 1 facteur de stress aigu. Nous faisons également état de la survenue simultanée de la CTT et de l'amnésie globale transitoire. Ce cas illustre que la CTT peut survenir sans facteur de stress typique et qu'elle devrait néanmoins être considérée dans le contexte clinique approprié. La survenue concomitante de la CTT et de l'amnésie globale transitoire n'est pas fréquente, mais peut résulter de 2 affections ayant possiblement en commun une étiologie sous-jacente.

Clinical outcomes of cardiac resynchronization therapy with and without a defibrillator in elderly patients with heart failure.

BACKGROUND: Evidence regarding the incremental benefit of cardiac resynchronization therapy (CRT) with a defibrillator (CRT-D) versus without (CRT-P) in elderly patients with heart failure is limited. We compared mortality and cardiac hospitalisation between CRT-D and CRT-P in the elderly. METHODS: A retrospective chart review identified all consecutive patients with age ≥75 with CRT implantation over the last 10 years at a Canadian tertiary care cardiac centre. Kaplan-Meier survival analyses and cumulative incidence curves were used to compare mortality and time to first cardiac hospitalisation, respectively, with CRT-D versus CRT-P over a 3 year period. Analyses were also repeated with propensity score matching based on age, sex, primary versus secondary prevention, date of implant, and Charlson Comorbidity Index. RESULTS: One hundred and seventy CRT patients were identified. A total of 128 received CRT-D while 42 received CRT-P. Median age was 79 (IQR 77-81), and the majority were male (83%). CRT-P patients had a higher burden of comorbidities (Charlson score 7, IQR 6-8) than CRT-D patients (Charlson score 5, IQR 5-7; P < 0.001). There was no significant difference in survival between the two groups in an unmatched comparison (P = 0.69) and with a propensity score-matched cohort (P = 0.91). Secondary prevention CRT-D patients had a higher risk of hospitalisation compared to primary prevention CRT-D patients; however, there was no significant difference in hospitalisation between the CRT-D and CRT-P groups. CONCLUSION: This study suggests there is no significant difference in mortality or cardiac hospitalisation between CRT-D and CRT-P in elderly patients with heart failure.

Physician decision making in anticoagulating atrial fibrillation: a prospective survey of a physician notification system for atrial fibrillation detected on cardiac implantable electronic devices of patients at increased risk of stroke.

OBJECTIVES: The objectives of this study were to evaluate the effectiveness of a physician notification system for atrial fibrillation (AF) detected on cardiac devices, and to assess predictors of anticoagulation in patients with device-detected AF. METHODS: In 2013, a physician notification system for AF detected on a patient's CIED [including pacemakers, implantable cardioverter defibrillators (ICD) or cardiac resynchronization therapy (CRT) devices] was implemented, with a recommendation to consider oral anticoagulation in high-risk patients. We prospectively investigated the effectiveness of this system, and evaluated both patient and physician predictors of anticoagulation, as well as factors influencing physician decision making in prescribing anticoagulation. Both uni- and multivariable analysis as well as descriptive statistics were used in the analysis. RESULTS: We identified 177 patients with device-detected AF, 126 with a CHADS2 ⩾2. Only 41% were prescribed anticoagulation at any point within 12 months. On multivariable analysis, stroke risk as predicted by CHADS2 was not a predictor of anticoagulation. ASA use predicted a lower rate of anticoagulation (OR 0.39, 95% CI 0.16-0.97, p = 0.04); physicians in practice for <20 years were more likely to prescribe anticoagulation (OR 3.39, 95% CI 1.28-8.93, p = 0.01); and physicians who believed both cardiologist and family doctor should be involved in managing anticoagulation were more likely to prescribe anticoagulation (OR 3.28, 95% CI 1.02-10.5, p = 0.05). CONCLUSIONS: Patients on aspirin were less likely to be anticoagulated. Physicians in practice for <20 years and who believed that both the general practitioner and cardiologist should be involved in managing anticoagulants were more likely to prescribe anticoagulation.

Physician decision making in anticoagulating atrial fibrillation: a prospective survey of a physician notification system for atrial fibrillation detected on cardiac implantable electronic devices of patients at increased risk of stroke.

OBJECTIVES: The objectives of this study were to evaluate the effectiveness of a physician notification system for atrial fibrillation (AF) detected on cardiac devices, and to assess predictors of anticoagulation in patients with device-detected AF. METHODS: In 2013, a physician notification system for AF detected on a patient's CIED [including pacemakers, implantable cardioverter defibrillators (ICD) or cardiac resynchronization therapy (CRT) devices] was implemented, with a recommendation to consider oral anticoagulation in high-risk patients. We prospectively investigated the effectiveness of this system, and evaluated both patient and physician predictors of anticoagulation, as well as factors influencing physician decision making in prescribing anticoagulation. Both uni- and multivariable analysis as well as descriptive statistics were used in the analysis. RESULTS: We identified 177 patients with device-detected AF, 126 with a CHADS2 ⩾2. Only 41% were prescribed anticoagulation at any point within 12 months. On multivariable analysis, stroke risk as predicted by CHADS2 was not a predictor of anticoagulation. ASA use predicted a lower rate of anticoagulation (OR 0.39, 95% CI 0.16-0.97, p = 0.04); physicians in practice for <20 years were more likely to prescribe anticoagulation (OR 3.39, 95% CI 1.28-8.93, p = 0.01); and physicians who believed both cardiologist and family doctor should be involved in managing anticoagulation were more likely to prescribe anticoagulation (OR 3.28, 95% CI 1.02-10.5, p = 0.05). CONCLUSIONS: Patients on aspirin were less likely to be anticoagulated. Physicians in practice for <20 years and who believed that both the general practitioner and cardiologist should be involved in managing anticoagulants were more likely to prescribe anticoagulation.

Patterns of aortic dilatation in bicuspid aortic valve-associated aortopathy.

BACKGROUND: Bicuspid aortic valves (BAVs) are associated with aortopathy. Recent studies suggest that aortic dilatation is more likely to be seen with left-right coronary cusp fusion (type I) compared with right-noncoronary cusp fusion (type II). The aim of this study was to investigate the association between BAV morphology and patterns of aortopathy. METHODS: Aortic dimensions and BAV morphology were obtained retrospectively from archived cine loops of 581 consecutive patients with BAVs and 277 matched normal controls from the Vancouver General Hospital echocardiography database. Patient demographics and other echocardiographic parameters were extracted from the database. RESULTS: The study population was composed of 71% type I BAVs (415 patients) and 26% type II BAVs (149 patients). Aortic dilatation was present in 30% of the population. Type I BAV was associated with increased dimensions indexed to body surface area at the sinus of Valsalva compared with type II BAV. No difference in proximal ascending aortic dimension was seen between different BAV morphologies. The pattern of dilatation with type I BAV was more likely to be at the level of the annulus or sinus of Valsalva compared with type II BAV (62% vs 33%, P= .002). Type I BAV was an independent predictor of proximal aortic dilatation (odds ratio, 3.42; 95% confidence interval, 1.07-10.9). CONCLUSIONS: Type I BAV is associated with a greater likelihood of dilatation at the annulus and sinus of Valsalva. There is relative sparing of this region of the aorta in patients with type II BAVs. Individuals with different BAV morphologies may require different strategies of aortopathy surveillance.