Christopher Labos

Queen Elizabeth Health Complex

Background Post-defibrillation myocardial contractile dysfunction adversely affects the survival of patients after cardiac arrest. Attenuation of diastolic calcium (Ca²⁺) overload by stabilization of the cardiac ryanodine receptor (RyR2) is found to reduce refibrillation after long-duration ventricular fibrillation (LDVF). Objective In the present...

Background We developed a multi-axis lead (MaxLead) incorporating four electrodes arranged at the lead-tip organized in an equidistant tetrahedron. Here, we studied MaxLead performance in sensing, pacing and activation wavefront-direction analysis. Methods Sixteen explanted animal hearts (from 7 pigs, 7 sheep and 2 rabbits) were used. Pacing thres...

Introduction An important substrate for AF is fibrotic atrial myopathy. Identifying low‐voltage, myopathic regions during AF using traditional bipolar voltage mapping is limited by the directional‐dependency of wave propagation. Our objective was to evaluate directionally‐independent unipolar voltage mapping, but with far‐field cancellation, to ide...

Background Action potential alternans can induce ventricular tachyarrhythmias and manifest on the surface ECG as T‐wave alternans (TWA) and QRS alternans (QRSA). We sought to evaluate microvolt QRSA in cardiomyopathy patients in relation to TWA and ventricular tachyarrhythmia outcomes. Methods and Results Prospectively enrolled cardiomyopathy pati...

Background The ODYSSEY OUTCOMES (Alirocumab and Cardiovascular Outcomes after Acute Coronary Syndrome) trial demonstrated that alirocumab reduced major cardiovascular events. However, because of the hierarchical testing strategy used for the multiple outcomes examined, the observed reduction in all‐cause mortality was labeled “nominally significant...

Aims Bipolar electrogram (BiEGM)-based substrate maps are heavily influenced by direction of a wavefront to the mapping bipole. In this study, we evaluate high-resolution, orientation-independent peak-to-peak voltage (Vpp) maps obtained with an equi-spaced electrode array and omnipolar EGMs (OTEGMs), measure its beat-to-beat consistency, and asses...

Background: Transcatheter Closure (TC) has become the main stay therapy for many secundum atrial septal defects (ASD) based on short and intermediate term outcome data. Long-term safety and efficacy of this approach among adult patients however, is not well established. Methods and results: A comprehensive search of major electronic databases fo...

Purpose of review: This review aims to summarize the research on genetic risk scores and their ability to improve risk prediction in both a primary and a secondary prevention population. Recent findings: Several groups have examined the role of genetic scores in different patient populations. Recent studies have capitalized on the growing number...

Objective: To reanalyze data from recent randomized trials of statins to assess whether the benefits and risks of statins are mediated primarily via their LDL-C (low-density lipoprotein cholesterol) lowering effects or via other mechanisms. Approach and results: We adapted Egger regression, a technique frequently used in Mendelian randomization...

Background/aims: Lynch syndrome (LS) is the most common hereditary colorectal cancer syndrome, caused by germline mutations in mismatch-repair genes. Besides a lifetime risk of colorectal cancer averaging 70%-80%, there is an increased risk of extracolonic tumors including gastric cancer. The utility of screening gastroscopy in Lynch syndrome has...

Background: Lipoprotein(a) concentrations in plasma are associated with cardiovascular risk in the general population. Whether lipoprotein(a) concentrations or LPA genetic variants predict long-term mortality in patients with established coronary heart disease remains less clear. Methods: We obtained data from 3313 patients with established coro...

Delays in reperfusion for patients with myocardial ischemia leads to increased morbidity and mortality. The objectives of this review was to identify, evaluate and critically-appraise the evidence on whether pre-hospital ECG reduces patient mortality and improves post-STEMI patient-oriented outcomes. We searched PubMed/MEDLINE, EMBASE and Cochrane...

Objective: A genetic risk score (GRS) for coronary artery disease has recently been shown to be independent of family history (FHx) in predicting future cardiovascular events. We sought to determine whether the presence of these risk factors, either individually or together, was associated with a higher burden of angiographic coronary artery disea...

Background: Contributory evidence on a direct association between asymptomatic atrial fibrillation (AF) burden and thromboembolic events is conflicting and contradictory. The aim of the article is to gather evidence available for a direct correlation between burden and stroke. Methods: A literature search was performed to capture studies reporti...

Limited evidence exists regarding the utility of genetic risk scores (GRS) in predicting recurrent cardiovascular events after acute coronary syndrome (ACS). We sought to determine whether a GRS would predict early recurrent cardiovascular events within 1 year of ACS. Participants admitted with acute coronary syndromes from the RISCA, PRAXY, and TR...

Whether implantable cardioverter defibrillator (ICD) discharges actively contribute to a worse prognosis independent of the underlying arrhythmia is unknown. There is considerable variability in the reported risk of mortality after appropriate and inappropriate ICD shocks. The aim of our systematic review is to provide a reliable effect size of the...

Michaelsson and colleagues’ article attempted to link milk consumption with fracture risk and mortality, especially cardiovascular mortality.1 The authors correctly note that residual confounding may be at play here, especially because their multivariate model did not adjust for osteoporosis or bone mineral density. Adjusting only for calcium and...

Background: The optimal revascularization technique in diabetic patients is an important unresolved question. Purpose: To compare long-term outcomes between the revascularization techniques of percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG). Data sources: English-language publications in PubMed, the Cochrane...

Background: Hyperbilirubinemia is associated with increased mortality in heart failure (HF) patients. We evaluated the impact of evidence-based medical therapy, in particular beta-blocker on the survival of patients with HF and hyperbilirubinemia. Methods and Results: We reviewed the charts of all patients followed at our tertiary care heart f...

Objective To examine the association between traditional risk factors (TRF) and a Genetic Risk Score (GRS) with age of first acute coronary syndrome (ACS). Early onset ACS may occur due to a high burden of TRFs or to genetic factors that accelerate atherosclerosis. Whether recently discovered genetic variants for ACS are more prevalent at earlier a...

Background: Early onset myocardial infarction (MI) is frequently attributed to genetic factors that may accelerate the atherosclerotic process. However, early MI may also occur due to a high burden of traditional risk factors. We sought to examine the association between traditional risk factors as well as a genetic risk score on the age of a first...

Patients prescribed antiplatelet treatment to prevent recurrent acute myocardial infarction are often also given a selective serotonin reuptake inhibitor (SSRI) to treat coexisting depression. Use of either treatment may increase the risk of bleeding. We assessed the risk of bleeding among patients taking both medications following acute myocardial...

Pancytopenia secondary to hepatitis viral infection is a rare but noted clinical entity. An acute aplastic crisis usually occurs shortly after viral infection, however, viral serologies are usually negative and the pancytopenia is often fatal if left untreated. A 66-year-old woman presented to the emergency department with shortness of breath and p...