October 14th, 2013
Selections from Richard Lehman’s Literature Review: October 14th
CardioExchange is pleased to reprint this selection from Dr. Richard Lehman’s weekly journal review blog at BMJ.com. Selected summaries are relevant to our audience, but we encourage members to engage with the entire blog.
NEJM 10 Oct 2013 Vol 369
Cardiac-Resynchronization Therapy in HF with a Narrow QRS Complex (pg. 1395): It’s been known for at least four thousand years that the heart has two ventricles, but what they actually did was a source of confusion until William Harvey began to sort things out in the seventeenth century. In the twenty-first century, cardiologists remain obsessed with the left ventricle and usually define “heart failure” by the proportion of its contents expelled in each contraction—the left systolic ejection fraction. In this trial, participants were selected for having an EF of 35% or less, normal QRS duration on ECG, and some echographic evidence that their right ventricle did not beat in exact synchrony with the left. These people were also considered suitable for an implantable cardioverter-defibrillator, so they were fitted with one of these plus a biventricular pacemaker, but in half the subjects, this was switched off. By the time the trial was stopped for futility, 809 patients had been recruited and followed up for a mean of 19.4 months. “In patients with systolic heart failure and a QRS duration of less than 130 msec, cardiac resynchronization therapy does not reduce the rate of death or hospitalisation for heart failure and may increase mortality.” So for selecting patients to have CRT, measuring the QRS interval on the ECG beats echocardiograpy.
Edoxaban vs. Warfarin for the Treatment of Symptomatic VTE (pg. 1406): A trial of edoxaban versus warfarin for the treatment of symptomatic venous thromboembolism. OK, children, what is the first question we must ask? Yes, time within the INR target range for the warfarin group. Here it was 63.5%. Is that good or bad? It’s probably the current UK average, as far as I can discover. The authors describe this as “high-quality standard therapy:” compare it with your own figures, if you have them, before considering whether to use this latest fixed-dose factor Xa inhibitor. The new drug was as good for VTE as this degree of warfarin control, and caused less bleeding in this trial. For cognoscenti of natriuretic hormones, it’s also interesting that the Japanese investigators used NT-pro-BNP as a measure of right ventricular strain in pulmonary embolism. Nice to see this, 20 years after it was first proposed.
JAMA 9 Oct 2013 Vol 310
Risk of Major Adverse Cardiac Events Following Noncardiac Surgery in Patients With Coronary Stents (pg. 1462): Simple retrospective cohort studies often make nice easy reading, but I’m not sure if there is a great deal for generalists to take away from this one, which describes the risk of major adverse cardiac events following noncardiac surgery in patients with recently placed coronary stents. If this is a subject that interests you, you can read the full article for free. People who have non-cardiac surgery within two years of stent placement have a greater surgical risk in the first six months, and it is higher with emergency than with elective surgery, and relates to the degree of coronary disease and not significantly to the type of stent. Which all makes sense, but apparently contradicts current guidelines.
BMJ 12 Oct 2013 Vol 347
Aircraft noise and CVD near Heathrow airport in London: I am a cause of cardiovascular morbidity across the Northern hemisphere. Last week I caused atheroma in the citizens of inner London and outer Dresden, and this week I am doing the same for those of Slough, Boston (Mass), and Toronto. The noisy aeroplanes which have conveyed me to and from these destinations howl every few minutes over the tops of numerous homes of brick, concrete, or white clapboard, and the unfortunates who inhabit them are a teeny weeny bit more likely to end up in hospital with a cardiovascular diagnosis: “Averaged across all airports and using the 90th centile noise exposure metric, a zip code with 10 dB higher noise exposure had a 3.5% higher (95% confidence interval 0.2% to 7.0%) cardiovascular hospital admission rate, after controlling for covariates.” So scarcely worth making a big noise about, really.