Barry Burstein

Latitude, sunshine, and human lactase phenotype distributions may contribute to geographic patterns of modern disease: the inflammatory bowel disease model

Countries with high lactase nonpersistence (LNP) or low lactase persistence (LP) populations have lower rates of some “western” diseases, mimicking the effects of sunshine and latitude. Inflammatory bowel disease (IBD), ie, Crohn’s disease and ulcerative colitis, is putatively also influenced by sunshine. Recent availability of worldwide IBD rates and lactase distributions allows more extensive comparisons. The aim of this study was to evaluate the extent to which modern day lactase distributions interact with latitude, sunshine exposure, and IBD rates. National IBD rates, national distributions of LP/LNP, and population-weighted average national annual ultraviolet B exposure were obtained, estimated, or calculated from the literature. Negative binomial analysis was used to assess the relationship between the three parameters and IBD rates. Analyses for 55 countries were grouped in three geographic domains, ie, global, Europe, and non-Europe. In Europe, both latitude and ultraviolet B exposure correlate well with LP/LNP and IBD. In non-Europe, latitude and ultraviolet B exposure correlate weakly with LP/LNP, but the latter retains a more robust correlation with IBD. In univariate analysis, latitude, ultraviolet B exposure, and LP/LNP all had significant relationships with IBD. Multivariate analysis showed that lactase distributions provided the best model of fit for IBD. The model of IBD reveals the evolutionary effects of the human lactase divide, and suggests that latitude, ultraviolet B exposure, and LP/LNP mimic each other because LP/LNP follows latitudinal directions toward the equator. However, on a large scale, lactase patterns also follow lateral polarity. The effects of LP/LNP in disease are likely to involve complex interactions.

Significant Positive Correlation Between Sunshine and Lactase Nonpersistence in Europe May Implicate Both in Similarly Altering Risks for Some Diseases

Decreasing latitude and increasing frequency of population lactase nonpersistence have been reported to diminish risks for several diseases, but the reason for overlap has not been explained. We evaluate, relationships between calculated national annual ultraviolet light B (UVB) exposure, latitude, and national lactose digestion frequencies. Annual UVB exposure and latitude were based on weighted averages from several cities in different countries. Lactase distribution status was based on published data that have been used previously to derive relations with diseases. We compare univariate regression analyses (r2 adj, slope) of percentage of lactase nonpersistence with UVB or latitude. We determine, differences between European and non-European sources by multiregression analysis of independent variables. Correlation between UVB and latitude is high (r2 = 0.89), and between percentage of lactase nonpersistence and either latitude or UVB the correlation is moderately strong with r2 = 0.51 and 0.46, respectively, with P ≤ 0.01 for both. A more detailed analysis shows that correlations between percentage of lactase nonpersistence and UVB are only significant in Europe, r2 = 0.59, P < 0.001, whereas outside Europe: r2 = 0.06, P = 0.16. These relationships raise hypothetical explanations to account for the observed overlap in similar risk modification by the 2 variables.

Venous Thrombosis After Electrophysiology Procedures: A Systematic Review

BACKGROUND: Femoral venous access for catheter introduction represents the cornerstone of electrophysiology (EP) procedures. Limited data are available regarding postprocedure VTE. The aim of this systematic review is to determine the incidence of DVT and pulmonary embolism (PE) associated with femoral vein catheterization during EP procedures. METHODS: An electronic search was conducted for studies documenting the incidence of DVT and PE after EP procedures. Studies were classified as atrial fibrillation (AF) or non‐AF ablation procedures. RESULTS: Two thousand eight‐hundred sixty‐four studies were evaluated, 16 of which were included in the analysis. The incidence of DVT after AF and non‐AF ablations reached as high as 0.33% and 2.38%, respectively, with a pooled incidence of 0% (95% CI, 0%‐0.0003%) and 0.24% (95% CI, 0.08%‐0.39%), respectively. The incidence of PE was 0.29% after AF ablation and ranged from 0% to 1.67% for non‐AF procedures; the pooled incidence after non‐AF ablations was 0.12% (95% CI, 0%‐0.25%). Asymptomatic DVT was documented in up to 21.2% of patients. Hematomas occurred in 1.05% of AF ablations (95% CI, 0.30%‐1.8%) and 0.3% of non‐AF ablations (95% CI, 0.09%‐0.51%). CONCLUSIONS: A lower incidence of symptomatic DVT and PE was observed after AF ablations as opposed to non‐AF ablations, likely due to the use of routine periprocedural anticoagulation. Asymptomatic DVTs appear to be common, although their significance is unclear. Future studies are required to weigh the risk of hematoma against the risk of VTE associated with the use of prophylactic anticoagulation after non‐AF ablation procedures.

Pattern of initiation of monomorphic ventricular tachycardia and implications on tachycardia mechanism.

The incidence of sudden cardiac death, predominantly caused by ventricular tachycardia and ventricular fibrillation, is high in patients with congestive heart failure. Implantable cardiac defibrillators have improved survival in this population but defibrillator shocks can lead to low quality of life and heart failure progression. The current management of recurrent ventricular tachycardia includes ablation and anti-arrhythmic drugs and both are associated with high recurrence rates. Better understanding the mechanism of ventricular tachycardia allowing individualization of treatment may improve outcomes. Re-entry is currently accepted as the mechanism of the majority of monomorphic ventricular tachycardias in patients with congestive heart failure, being responsible for more than 90% of the ventricular tachycardia in patients with ischemic cardiomyopathy. On the other hand, some studies show a greater participation of focal arrhythmias in the genesis of ventricular tachycardia in this population. The pattern of initiation of ventricular tachycardia is divided into sudden, when the first beat of the tachycardia is morphologically similar to the rest of the tachycardia, and non-sudden, when its morphology is dissimilar. An association between the pattern of the initiation and the mechanism of ventricular tachycardia has been proposed. The pattern of initiation of ventricular tachycardia is a readily available from data stored in current generation implantable cardiac defibrillators. The association with tachycardia mechanism may allow individualization of the therapy, however evidence is lacking and further research is required.

Early left ventricular ejection fraction as a predictor of survival after cardiac arrest

ABSTRACT Background: Cardiopulmonary resuscitation and early defibrillation have been shown to improve outcomes of cardiac arrest. The significance of the post-arrest echocardiogram, specifically the left ventricular ejection fraction (LVEF) is unknown. Methods: We performed a retrospective cohort study of patients who suffered from cardiac arrest between 1 January 2009 and 31 December 2013. We included all patients who achieved return of spontaneous circulation (ROSC), and were admitted to the intensive care unit (ICU) or coronary care unit (CCU) of a tertiary care academic center. Patients who underwent echocardiography within 24 h of cardiac arrest were included for analysis. The primary outcome was survival. Results: We identified 151 patients who achieved ROSC of which 97 underwent post-arrest echocardiogram within 24 h. 70.8% were males and the mean age was 67.8 years (SD: 15.9). The mean LVEF at 24 h was 35.7 (SD: 17.8). LVEF > 40% was not a predictor of survival at 30 days or hospital discharge. The only significant predictors on multivariate analyses were age, presence of shockable rhythm and time to ROSC. Conclusion: Although echocardiograms are frequently ordered, LVEF greater than 40% in patients who are resuscitated after a cardiac arrest is not a predictor of survival.

Defining the Pattern of Initiation of Monomorphic Ventricular Tachycardia Using the Beat-to-Beat Intervals Recorded on Implantable Cardioverter Defibrillators from the RAFT Study: A Computer-Based Algorithm

Arrhythmia onset pattern may have important implications on morbidity, recurrent implantable cardioverter defibrillator (ICD) shocks, and mortality, given the proposed correlation between initiation pattern and arrhythmia mechanism. Therefore, we developed and tested a computer-based algorithm to differentiate the pattern of initiation based on the beat-to-beat intervals of the ventricular tachycardia (VT) episodes in ICD recordings from the Resynchronization-Defibrillation for Ambulatory Heart Failure Trial (RAFT). Intervals on intracardiac electrograms from ICDs were analyzed backwards starting from the marker of VT detection, comparing each interval with the average tachycardia cycle length. If the morphology of the beat initiating the VT was similar to the morphology of the VT itself, the episode was considered sudden. If the morphology of the beat initiating the VT was not similar to the morphology of the VT itself, the episode was considered non-sudden. The capability of the algorithm to classify the pattern of initiation based only on the beat-to-beat intervals allows for the classification and analysis of large datasets to further investigate the clinical importance of classifying VT initiation. If analysis of the VT initiation proves to be of clinical value, this algorithm could potentially be integrated into ICD software, which would make it easily accessible and potentially helpful in clinical decision-making.

Right ventricular ST-elevation myocardial infarction as a cause of death in idiopathic pulmonary arterial hypertension:

A 32-year-old woman with advanced idiopathic pulmonary arterial hypertension (PAH), treated with oral tadalafil and intravenous epoprostenol, presented with typical angina pectoris of one day’s duration. Her electrocardiogram, previously typical of pulmonary hypertension, revealed an acute ST-elevation myocardial infarction in the anterior precordial leads. She had a prior coronary angiogram, in preparation for lung transplantation, that revealed normal coronary arteries. Urgent coronary angiography showed acute occlusion of several acute marginal coronary branches that feed the right ventricle (RV). Coronary angioplasty and stenting was unable to adequately restore coronary perfusion. Despite support, she developed progressive cardiogenic shock and died three days later. This is an unusual complication of PAH.

Impact of Heart Outcomes Prevention Evaluation Trial on Statin Eligibility for the Primary Prevention of Cardiovascular Disease: Insights from the National Health and Nutrition Examination Survey

The American College of Cardiology (ACC)/American Heart Association (AHA) guidelines suggest statin therapy for primary prevention in patients with an estimated 10-year atherosclerotic cardiovascular disease risk ≥7.5%1 as calculated by the Pooled Cohorts Equation. We recently demonstrated that only 53% of individuals eligible for statins based on the ≥7.5% risk criterion would have been eligible for a statin randomized control trial (RCT) in which benefit was demonstrated.2 We sought (1) to evaluate whether the recently published HOPE-3 trial (Heart Outcomes Prevention Evaluation)3 improves the evidence base for the ACC/AHA guidelines and (2) to estimate whether HOPE-3 increases the number of individuals eligible for statins in primary prevention beyond those recommended by the ACC/AHA guidelines. Data from the National Health and Nutrition Examination Survey (NHANES) collected between 2005 and 2010 were used to create a sample of 2134 participants representing 71.8 million Americans without atherosclerotic cardiovascular disease who were not currently taking statins. Participants were categorized based on the following criteria: (1) a 10-year risk of ≥7.5% by Pooled Cohorts Equation; (2) an expected absolute risk reduction of ≥2.3% based on Pooled Cohorts Equation risk and individualized relative risk reductions, as previously described2; …