May 6, 2020

There continues to be a slew of publications coming out on a near daily basis in regard to COVID-19.  Some publications will deserve their own posts and others can really be summarized in one or two paragraphs.  In this post I will summarize 5 papers published in the past week, that I found interesting and each has a unique, but important message.  None of these papers are very long, but there are some important aspects of each I felt tied into each other from a cardiovascular standpoint.

April 27, 2020

Background: In patients with stable coronary artery disease the goals of treatment are to reduce the risk of death, ischemic events, and to improve quality of life. In order to achieve those objectives all patients with coronary artery disease should be treated with guideline based medical therapy. Currently, many of them undergo elective angiography and placement of stents if needed when they have abnormal stress tests. Before the widespread use of drug-eluting stents, trials evaluating incremental effects of revascularization added to medical therapy did not show a reduction in the rates of death or MI. However, those trials did not include sufficient numbers of participants, and only included those with known coronary anatomy prior to randomization.

REBEL Review 100: Canadian Syncope Risk Score

Created April 25, 2020 | Cardiovascular | DOWNLOAD

April 20, 2020

Background Information: The presentation of a patient with syncope to the Emergency Department (ED) can pose a challenge to clinicians as the identification of a serious underlying condition is the priority. Often the original cause of the syncope is difficult to determine in the ED and ultimately results in unnecessary hospitalization. Of all syncope patients evaluated in the ED, 3-5% of them will be found to have a serious condition after ED disposition.1 Furthermore, the literature has shown that hospital admissions due to syncope were associated with low mortality or the need for procedures.2 Emergency physicians are then also posed with the task of determining which patients may be considered low, medium and high risk for a serious outcome. Several risk stratification tools have been developed to help with the identification of these patients, however many of these tools are not validated and very complex, therefore they are not used clinically. The Canadian Syncope Risk Score (CSRS) is among these decision tools, however it has yet to be validated. The authors of this paper sought to conduct a multicenter ED based prospective study to validate this tool and advocate its superior use over some of the other risk stratification tools that currently exist.

March 26, 2020

Background Information: Refractory ventricular fibrillation (RVF) is a complication of cardiac arrest defined as ventricular fibrillation (VF) that does not respond to three or more standard defibrillation attempts.1,2 Patients with RVF during their cardiac arrest have a mortality of up to 97%.3,4 Double external defibrillation (DED) involves the use of a second defibrillator providing an additional shock in a sequential or simultaneous manner. The left ventricle (LV), being the most posterior part of the heart and the furthest away from the anterolateral electrode pads, have led some to hypothesize that utilizing an anterior-posterior pad placement (ie. Changing the vector) is what accounts for DED’s success. Some theorize that the increase in amount of energy from two defibrillations as opposed to one is what’s needed to reach the LV. There are also theories suggesting that the sequential administration of the shocks, more effectively lowers the defibrillation threshold of the cardiac myocytes and thus leads to a more successful conversion of VF. In spite of these many theories, the intervention of DED has been studied for decades in the electrophysiology lab and widely discussed in the literature through case reports and meta-reviews. These case reports have shown success and a recent meta-review of 39 patients who received DED showed that 25% of them were discharged neurologically intact with Cerebral Performance Category (CPC) scores of 2 or less indicating normal recovery/mild disability or moderate disability but able to independently perform activities of daily living.5-10 While this literature is promising, DED is a highly variable intervention and there are still many unknown factors which continue to cause debate and controversy. The role of vector direction via pad placement, the role of a pulse interval in energy deliverance and the efficacy in method of delivering DED sequentially vs simultaneously continues to remain unclear. 6-11 The authors of this pilot RCT (DOSE VF) wished to answer some of these questions by first determining the feasibility and safety of performing a full RCT.  In doing so, they used alternate defibrillation strategies such as vector changes and double external sequential defibrillation (DSED) in treating RVF.12
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