Efficacy of intravenous magnesium for the management of non-post operative atrial fibrillation with rapid ventricular response: A systematic review and meta-analysis.

BACKGROUND: Intravenous magnesium (IV Mg), a commonly utilized therapeutic agent in the management of atrial fibrillation (AF) with rapid ventricular response, is thought to exert its influence via its effect on cellular automaticity and prolongation of atrial and atrioventricular nodal refractoriness thus reducing ventricular rate. We sought to undertake a systematic review and meta-analysis of the effectiveness of IV Mg versus placebo in addition to standard pharmacotherapy in the rate and rhythm control of AF in the nonpostoperative patient cohort given that randomized control trials (RCTs) have shown conflicting results. METHODS: Randomized controlled trials comparing IV Mg versus placebo in addition to standard of care were identified via electronic database searches. Nine RCTs were returned with a total of 1048 patients. Primary efficacy endpoints were study-defined rate control and rhythm control/reversion to sinus rhythm. The secondary endpoint was patient experienced side effects. RESULTS: Our analysis found IV Mg in addition to standard care was successful in achieving rate control (odd ratio [OR] 1.87, 95% confidence interval [CI] 1.13-3.11, p = .02) and rhythm control (OR 1.45, 95% CI 1.04-2.03, p = .03). Although not well reported among studies, there was no significant difference between groups regarding the likelihood of experiencing side effects. CONCLUSIONS: IV Mg, in addition to standard-of-care pharmacotherapy, increases the rates of successful rate and rhythm control in nonpostoperative patients with AF with rapid ventricular response and is well tolerated.

Angiotensin-Converting Enzyme 2 Activity Is Associated With Embolic Stroke of Undetermined Source.

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The Effect of Transitional Care on 30-Day Outcomes in Patients Hospitalised With Acute Heart Failure.

BACKGROUND: Patients admitted to hospital with acute heart failure (AHF) are at increased risk of readmission and mortality post-discharge. The aim of the study was to examine health service utilisation within 30 days post-discharge from an AHF hospitalisation. METHODS: This was a prospective, observational, non-randomised study of consecutive patients hospitalised with acute HF to one of 16 Victorian hospitals over a 30-day period each year and followed up for 30 days post-discharge. The project was conducted annually over three consecutive years from 2015 to 2017. RESULTS: Of the 1,197 patients, 56.3% were male with an average age of 77±13.23 years. Over half of the patients (711, 62.5%) were referred to an outpatient clinic and a third (391, 34.4%) to a HF disease management program. In-hospital mortality was 5.1% with 30 day-mortality of 9% and readmission rate of 24.4%. Patients who experienced a subsequent readmission less than 10 days post-discharge and between 11 and 20 days post-discharge had a five- to six-fold increase in risk of mortality (adjusted OR 5.02, 95% CI 2.11-11.97; OR 6.45, 95% CI 2.69-15.42; respectively) compared to patients who were not readmitted to hospital. An outpatient appointment within 30 days post-discharge significantly reduced the risk of 30-day mortality by 81% (95% CI 0.09-0.43). CONCLUSION: Patients admitted to hospital with AHF who experience a subsequent readmission within 20 days post-discharge are at increased risk of dying. However, early follow-up post-discharge may reduce this risk. Early post-discharge follow-up is vital to address this vulnerable period after a HF admission.

The Atrium and Embolic Stroke: Myopathy Not Atrial Fibrillation as the Requisite Determinant?

Atrial fibrillation (AF) is well-recognized in the pathophysiology of left atrial thrombogenesis and resultant cardioembolic stroke. Subclinical AF is believed to account for a significant proportion of embolic stroke. However, recent randomized control trials failed to demonstrate a significant benefit for oral anticoagulation, in an unselected population with embolic stroke of undetermined source. This has reinvigorated the focus on finding robust markers to identify patients at risk of cardioembolic stroke. Several nonfibrillatory atrial electrical markers, along with structural and biochemical abnormalities, have been associated with ischemic stroke, independently of AF. An increasingly complex relationship exists among vascular risk factors, atrial remodeling, and thrombogenesis. Identifying robust markers of an underlying atrial myopathy may allow for early identification of patients at risk for cardioembolic stroke. This review outlines the inconsistencies in the evidence for AF as the prerequisite for left atrial thrombogenesis and embolic stroke. It will highlight the current evidence and controversies for adverse atrial remodeling, independent from rhythm, as a plausible mechanism for left atrial thrombogenesis and ischemic stroke.

Association between excessive premature atrial complexes and cryptogenic stroke: results of a case-control study.

OBJECTIVE: Recent anticoagulation trials in all-comer cryptogenic stroke patients have yielded equivocal results, reinvigorating the focus on identifying reproducible markers of an atrial myopathy. We investigated the role of excessive premature atrial complexes (PACs) in ischaemic stroke, including cryptogenic stroke and its association with vascular risk factors. METHODS AND RESULTS: A case-control study was conducted utilising a multicentre institutional stroke database to compare 461 patients with an ischaemic stroke or transient ischaemic attack (TIA) with a control group consisting of age matched patients without prior history of ischaemic stroke/TIA. All patients underwent 24-hour Holter monitoring during the study period and atrial fibrillation was excluded. An excessive PAC burden, defined as ≥200 PACs/24 hours, was present in 25.6% and 14.7% (p<0.01), of stroke/TIA and control patients, respectively. On multivariate regression, excessive PACs (OR 1.97; 95% CI 1.29 to 3.02; p<0.01), smoking (OR 1.58; 95% CI 1.06 to 2.36; p<0.05) and hypertension (OR 1.53; 95% CI 1.07 to 2.17; p<0.05) were independently associated with ischaemic stroke/TIA. Excessive PACs remained the strongest independent risk factor for the cryptogenic stroke subtype (OR 1.95; 95% CI 1.16 to 3.28; p<0.05). Vascular risk factors that promote atrial remodelling, increasing age (≥75 years, OR 3.64; 95% CI 2.08 to 6.36; p<0.01) and hypertension (OR 1.54; 95% CI 1.01 to 2.34; p<0.05) were independently associated with excessive PACs. CONCLUSIONS: Excessive PACs are independently associated with cryptogenic stroke and may be a reproducible marker of atrial myopathy. Prospective studies assessing their utility in guiding stroke prevention strategies may be warranted.

Poor reliability of P-wave terminal force V1 in ischemic stroke.

INTRODUCTION: Several ECG markers are postulated to represent underlying atrial remodelling and have been associated with ischemic stroke. P-wave terminal force in lead V1 (PTFV1) is one such marker. We examined the factors that contribute to the reliability of PTFV1 and its association with ischemic stroke. MATERIAL AND METHODS: Four hundred and thirty-five patients that presented with an ischemic stroke or transient ischemic attack (TIA) were identified through a prospectively maintained multi-site institutional stroke database. Control group consisted of age matched patients without prior history of an ischemic stroke or TIA. All patients underwent a 12-lead ECG and 24-hour Holter monitoring during the study period to exclude atrial fibrillation. RESULTS: Morphology consistent with PTFV1 occurred commonly in both the stroke/TIA and control groups. There was no significant difference in the median PTFV1 value between the stroke 3.96 mV ms [Interquartile range (IQR) 2.78-5.58] and control 4.23 mV ms [IQR 2.91-5.57] groups. Measurements of PTFV1 demonstrated excellent intra-observer reliability on assessment of the same P-wave (Intra class correlation (ICC) 0.91, p < 0.001) with narrow limits of agreement 2.21 to -2.95 mV ms. A change in the P wave assessed led to a significant reduction in reliability (ICC 0.79, p < 0.001). Inter-observer, inter P-wave assessment demonstrated further reduction in reliability (ICC 0.68, p < 0.002) with wide limits of agreement 6.17 to -5.78 mV ms, indicating significant under and overestimation of PTFV1. CONCLUSION: The utility of PTFV1 as a clinical marker for ischemic stroke is limited by the reduction in reliability associated with inter-observer and inter P-wave measurements.

Accuracy of blinded clinician interpretation of single-lead smartphone electrocardiograms and a proposed clinical workflow.

Despite the appeal of smartphone-based electrocardiograms (ECGs) for arrhythmia screening, a paucity of data exists on the accuracy of primary care physicians' and cardiologists' interpretation of tracings compared with the device's automated diagnosis. Using 408 ECGs in 51 patients, we demonstrate a variable accuracy in clinician interpretation of smartphone-based ECGs, with only cardiologists demonstrating satisfactory agreement when referenced against a 12-lead ECG. Combining the device automated diagnostic algorithm with cardiologist interpretation of only uninterpretable traces yielded excellent results and provides an efficient, cost-effective workflow for the utilization of a smartphone-based ECG in clinical practice.

"Inverted" tako-tsubo cardiomyopathy due to exogenous catecholamines.

Inverted tako-tsubo cardiomyopathy (TTC) is a variation of stress cardiomyopathy. It features transient myocardial dysfunction characterised by a typical contractile abnormality consisting of extensive left ventricular circumferential dyskinesia or akinesia with a hyperkinetic apex. Endogenous catecholamine surges are believed to be the mediators of this potentially life-threatening condition. We describe a patient who received an inadvertent bolus of noradrenaline and developed significant haemodynamic instability associated with electrocardiographic and cardiac biomarkers indicative of diffuse myocardial injury and echocardiography findings of an "inverted" TTC. The patient made a full recovery. Our case highlights that a reversible inverted TTC may result from an exogenous catecholamine surge.

Interpretation of plasma brain natriuretic peptide concentrations may require adjustment for patient's age.

BACKGROUND: Brain natriuretic peptide (BNP) is increasingly recognized as a practical, reliable and accurate indicator of left ventricular function and may have an important prognostic role in determining outcome following myocardial infarction and heart failure. METHODS AND RESULTS: We studied a total of 60 patients referred for dobutamine-stress echocardiography to evaluate possible reversible myocardial ischaemia. There was no echocardiographic evidence of structural or functional heart disease in any of the patients included in the study. Blood was sampled for BNP at rest, prior to dobutamine-stress. We found a significant linear correlation between BNP concentrations and patients' age, in the absence of structural or functional heart disease (r(s) = 0.53, 95% CI 0.25-0.73, P<0.0001). CONCLUSION: Our observations suggest the need for consideration of patient's age when interpreting BNP concentrations in the population.