Left Atrial Function Using Cardiovascular Magnetic Resonance Imaging Independently Predicts Life-Threatening Arrhythmias in Patients Referred to Receive a Primary Prevention Implantable Cardioverter Defibrillator

BackgroundIn this study we aimed to investigate left atrial (LA) function, measured from routine cine cardiovascular magnetic resonance imaging, to determine its value for the prediction of sudden cardiac death (SCD) or appropriate implantable cardioverter defibrillator (ICD) shock in patients who received primary prevention ICD implantation.MethodsWe studied 203 patients with ischemic or idiopathic nonischemic dilated cardiomyopathy who underwent cardiovascular magnetic resonance imaging before primary prevention ICD implantation. LA volumes were measured at end-diastole and end-systole from 4- and 2-chamber cine images, and LA emptying function (LAEF) calculated. Patients were followed for the primary composite end point of SCD or appropriate ICD shock.ResultsMean age was 61 ± 12 years with a mean left ventricular ejection fraction of 24 ± 7%. The mean LAEF was 27 ± 15% (range, 0.9%-73%). At a median follow-up of 1639 days, 35 patients (17%) experienced the primary composite outcome. LAEF was strongly associated with the primary outcome (P = 0.001); patients with an LAEF ≤ 30% experienced a cumulative event rate of 26.1% vs 5.7% (hazard ratio, 5.5; P < 0.001) in patients above this cutoff. This finding was maintained in multivariable analysis (hazard ratio, 4.7; P = 0.002) and was consistently shown in the ischemic and nonischemic dilated cardiomyopathy subgroups.ConclusionsLAEF is a simple, powerful, and independent predictor of SCD in patients being referred for primary prevention ICD implantation.     

Contemporary Emergency Department Management of Patients with Chest Pain: A Concise Review and Guide for the High-Sensitivity Troponin Era

This article synthesizes current best evidence for the evaluation of patients with suspected acute coronary syndrome (ACS) using high-sensitivity troponin assays, enabling physicians to effectively incorporate them into practice. Unlike conventional assays, high-sensitivity assays can precisely measure blood cardiac troponin concentrations in the vast majority of healthy individuals, facilitating the creation of rapid diagnostic algorithms. Very low troponin concentrations on presentation accurately rule out acute myocardial infarction (AMI) and enable the discharge of approximately 20% of patients after a single test, whereas an additional 30%-40% of patients can be safely discharged after short-interval serial sampling in as little as 1 or 2 hours. In contrast, highly abnormal troponin concentrations on presentation (more than 5 times the upper reference limit) or rapidly rising levels on serial testing can rapidly rule in AMI with high specificity. However, approximately one-third of patients remain in a biomarker-indeterminate “observation zone” even after serial sampling. These patients pose a disposition challenge to clinicians because although the differential diagnosis of elevated troponin concentrations is broad, these patients have an increased risk for short-term major adverse cardiac events. Use of repeated serial troponin sampling and structured clinical prediction tools may assist disposition for these patients, because no validated pathways currently exist to guide clinicians. Ongoing research to tailor diagnostic thresholds to individual patient characteristics may enable improved diagnostic accuracy and usher in a new era of personalized medicine in the evaluation of suspected ACS.     

Minimally Invasive Surgical Aortic Valve Replacement: An Overview of Recent Advances

Aortic valve replacement (AVR) is the only definitive treatment for severe aortic stenosis. Options for valve replacement include surgical AVR (SAVR) and percutaneous transcatheter AVR. Although transcatheter AVR has recently been shown to be the optimal approach for high-risk patients, SAVR is the gold standard for patients with low and intermediate surgical risk. Advances in technique and innovations in rapid-deployment and sutureless valves have facilitated the development of a third alternative. Accumulating evidence suggests that minimally invasive SAVR can be performed as safely as conventional SAVR, and perhaps with less morbidity, allowing patients a quicker return to their productive lives. The following discussion outlines the surgical technique, patient selection and advances in valve design.     

Application of Syncope Guidelines in the Emergency Department Do Not Reduce Admission Rates: A Retrospective Cohort Study

Background

Low-risk syncope accounts for a large proportion of hospital admissions; however, inpatient investigations are often not necessary and are rarely diagnostic. Reducing the number of low-risk syncope admissions can likely lower health care resource consumption and overall expenditure. Application of syncope guidelines by physicians in the emergency department provides a standardized approach that may potentially reduce admissions and lead to health care resource utilization savings.

Telehealth for Remote Stroke Management

Stroke is a leading cause of adult disability and the fourth leading cause of death in Canada. Most strokes are ischemic and functional outcome is highly time-dependent, making fast diagnosis and treatment initiation crucial. This poses a challenge in vast geographical areas where stroke neurology expertise is only available in urban centres. In this article we review the rationale for telestroke networks and their current implementation in Canada. Telestroke networks enable stroke-specific procedures to be performed by less experienced physicians under the guidance of stroke neurology experts. We also present evidence that the safety and effectiveness of intravenous alteplase in community hospitals in a telestroke network seems to be comparable with that achieved in dedicated stroke centres. It is thus a viable option to guarantee an aging population access to stroke care across large geographic regions with faster treatment and access to more advanced treatment options by means of transfer to a comprehensive centre if necessary. Although telestroke networks have an upfront implementation cost, they can lead to reduced direct and indirect costs for the health care system by reducing days spent in the hospital as well as disability with the need for long-term care. Telestroke networks can also be used for identification and enrollment of patients into emergency stroke trials and thus provide a more representative sample of the population and increase recruitment. Standardization of regional telestroke networks could lead to collaborations with larger data acquisitions for research purposes and quality control in the future.     

Personalized Anticoagulation: Guided Apixaban Dose Adjustment to Compensate for Pharmacokinetic Abnormalities Related to Short-Bowel Syndrome

A 45-year-old woman who required lifelong anticoagulation for recurrent thrombosis had her therapeutic choices limited by heparin-induced thrombocytopenia and abnormal pharmacokinetics (greatly reduced absorption) resulting from short gut syndrome from extensive gut resection after mesenteric thrombosis. As an alternative to inconvenient and expensive injections of fondaparinux, personalized dosing of a direct oral anticoagulant was sought using clinical pharmacology techniques. Enteral absorption was ascertained with small test doses of apixaban, and the ability of supraconventional doses to deliver effective concentrations was verified.     

Assessment and Management of the Left Atrial Appendage Thrombus in Patients With Nonvalvular Atrial Fibrillation

Background

Intracardiac thrombi arising in the left atrial appendage (LAA) are the principal cause of stroke in nonvalvular atrial fibrillation (AF). Predicting the presence of LAA thrombi is of vital importance in stratifying patients that would need further LAA imaging prior to cardioversion or AF ablation.

Why Do Patients With Well-Controlled Vascular Risk Factors Develop Progressive Chronic Kidney Disease?

Cardiovascular disease and chronic kidney disease (CKD) share several common risk factors, and CKD itself is an independent and graded risk factor for cardiovascular disease. Although control of vascular risk factors is associated with improved kidney outcomes, certain patients still show CKD progression, highlighting that examination of other factors is warranted. In this review we explore how blood pressure and glycemic targets appear to differ for macro- vs microvascular disease. Furthermore, factors such as obstructive sleep apnea and obesity are associated with CKD progression. There is increasing recognition of how sex, gender, ethnicity, and socioeconomic position all factor into CKD progression. Uncertainty exists as to what is the optimal diet to prevent loss of kidney function. Last, complications of CKD might directly or indirectly contribute to progression of kidney disease. In conclusion, control of vascular risk factors reduces the risk of CKD progression, and careful consideration of these additional factors might ultimately result in improved cardiovascular and CKD outcomes.     

New Dimensions in Palliative Care Cardiology

The landscape of patient care at the beginning of the 19th century was dramatically different than it is today. With few good treatment options, illness courses were generally brief. Near the end of life, patients were attended to by spiritual advisors, not health care professionals. Death typically occurred at home, surrounded by friends and family. Moving to the present time, decades of medical advances have significantly improved life expectancy. Cardiology has particularly benefited from many of these advances. Cardiac patients are initiated on optimal medication regimens. As disease burdens progress, interventions such as implantable defibrillators and cardiac resynchronization pacing systems become options for many patients. With further clinical deterioration, select patients might be candidates for ventricular assist devices and heart transplants. These advances have unquestionably improved the prognosis with advanced cardiovascular illnesses. However, they have also changed patient and family attitudes about death and dying, to the point where we have effectively “medicalized our mortality.” The importance of introducing palliative care to the cardiac patient population is now well recognized, with the major cardiovascular societies incorporating palliative care principles into their guideline and consensus statement documents. However, despite this recognition, few cardiac patients get access to palliative care and other resources such as hospice. In this article the existing literature on this topic is reviewed and opportunities for developing and fostering a more collaborative relationship between the disciplines of cardiology and palliative care are discussed.     

The Extent of Left Atrial Low-Voltage Areas Included in Pulmonary Vein Isolation Is Associated With Freedom from Recurrent Atrial Arrhythmia

Background

The extent of left atrial (LA) baseline low-voltage areas (LVA-B), which may be a surrogate for fibrosis, is associated with recurrent atrial fibrillation (AF) after ablation. This study aimed to assess the relationship between the extent of LVA-B isolated by ablation (LVA-I) and AF recurrence.

Prognostic Value of Right Ventricular Strain Using Speckle-Tracking Echocardiography in Pulmonary Hypertension: A Systematic Review and Meta-analysis

Background

Right ventricular (RV) strain imaging using speckle-tracking echocardiography (STE) is a quantitative method of assessing RV systolic function that has shown prognostic utility in patients with pulmonary hypertension (PH). However, its prognostic value for a large and mixed PH population remains poorly defined.

Completion pancreatectomy in the acute management of pancreatic fistula after pancreaticoduodenectomy: a systematic review and qualitative synthesis of the literature

Background

Pancreatic fistula remains a major complication after pancreaticoduodenectomy (PD). Re-operation is generally considered only after exhaustion of non-surgical options. A variety of pancreas-preserving operations have been proposed, but completion pancreatectomy (CP) stands out in locally complicated cases as a universal approach. This study aims to provide a qualitative synthesis of the peer-reviewed literature regarding emergency CP for post-PD pancreatic fistula.

A Case of Palpitations Due to T-Wave Oversensing Caused by Sacubitril/Valsartan

A 58-year-old man with previous mitral/aortic mechanical-valve replacement, aortic root repair, and coronary disease developed severe left-ventricular dysfunction following AV-node ablation/single-chamber pacemaker implantation for management of atrial fibrillation. He then underwent an upgrade to cardiac resynchronization therapy with a defibrillator. To manage his heart failure better, angiotensin-receptor blocker therapy was changed to sacubitril/valsartan, after which symptomatic palpitations with T-wave oversensing occurred. The resolved T-wave oversensing and palpitations stopped upon discontinuation of sacubitril/valsartan and recurred upon rechallenge, requiring a switch back to valsartan monotherapy. Our report presents the first known case of T-wave oversensing due to sacubitril/valsartan.