Tag Archives: cardiology

Bloodtest Not Pertinent (BNP)

Despite a lack of evidence that it’s useful, many emergency departments have introduced BNP testing. Some smart Australians decided to properly evaluate its benefit the best way possible – with a randomised controlled trial on 612 patients with acute severe dyspnoea. Guess what? Clinician knowledge of BNP values in patients who presented with shortness of breath to the emergency department did not reduce the probability of hospital admission or alter management or length of hospital stay. The study findings do not support indiscriminate BNP testing in all dyspnoea patients, but do not rule out a possible role in patients with milder dyspnoea.

B-type natriuretic peptide testing, clinical outcomes, and health services use in emergency department patients with dyspnea: a randomized trial
Ann Intern Med. 2009 Mar 17;150(6):365-71

Rapid discharge in AF

The Ottawa Aggressive Protocol is used to treat recent onset (< 48 hours) atrial fibrillation or flutter with procainamide and/or cardioversion to allow discharge from the emergency department.
A cohort of 660 patient visits is described in a paper in the Canadian Journal of Emergency Medicine, 95.2% involving atrial fibrillation and 4.9% involving atrial flutter. The mean age of patients enrolled was 64.5 years. In total, 96.8% were discharged home and, of those, 93.3% were in sinus rhythm. All patients were initially administered intravenous procainamide, with a 58.3% conversion rate. A total of 243 patients underwent subsequent electrical cardioversion with a 91.7% success rate. Adverse events occurred in 7.6% of cases: hypotension 6.7%, bradycardia 0.3% and 7-day relapse 8.6%. There were no cases of torsades de pointes, stroke or death. The median lengths of stay in the ED were as follows: 4.9 hours overall, 3.9 hours for those undergoing conversion with procainamide and 6.5 hours for those requiring electrical conversion.

This proactive approach by emergency physicians seems excellent for patients who in some centres probably still get admitted for this presentation. I’m not sure why they continue to use a drug with a conversion percentage in the 50’s, which the authors have demonstrated before. Many of us routinely use flecainide for recent onset AF in patients likely to have structurally normal hearts, as it has been shown to be superior to procainamide in AF.

Association of the Ottawa Aggressive Protocol with rapid discharge of emergency department patients with recent-onset atrial fibrillation or flutter
Canadian Journal of Emergency Medicine 12.3 (May 2010): p181(11)

STEMI and PCI guidelines

Lots of interesting and up to date information in this thick document from December 2009

Full text is available here

2009 Focused Updates: ACC/AHA Guidelines for the Management of Patients With ST-Elevation Myocardial Infarction (Updating the 2004 Guideline and 2007 Focused Update) and ACC/AHA/SCAI Guidelines on Percutaneous Coronary Intervention (Updating the 2005 Guideline and 2007 Focused Update)

Echo best test for acute LVF in ED

Three diagnostic tests for acute left ventricular heart failure in dyspnoeic patients were compared, with the gold standard being the diagnosis by three independent reviewers (two cardiologists and one respiratory physician) who were blinded to the results of the tests being examined. The tests in question were  NT-proBNP, the Boston criteria, and limited echo performed by emergency physicians.

The primary goal of the echo study was the detection of the following echocardiographic variables, expressed as present or absent: reduced LV ejection fraction (LV ejection fraction <50% on subjective visual estimation of the change in LV size between diastole and systole) and the ‘‘restrictive’’ pattern on pulsed Doppler analysis of mitral inflow (using the apical view).

According to the authors, pulsed Doppler analysis of mitral inflow can be described by three patterns: 1) an ‘‘impaired relaxation’’ pattern, suggesting no increase in LV filling pressures; 2) a ‘‘normal’’ or ‘‘normalized’’ pattern; and 3) a restrictive pattern, suggesting an increase in LV filling pressures.

Trained emergency physicians were able to perform EDecho in a median of 4 minutes, obtaining Doppler data in an average of 80% of patients presenting for acute dyspnea. Considering the 125 patients with both EDecho variables available, reduced LV ejection fraction was less accurate than the restrictive mitral pattern for the diagnosis of aLVHF. The restrictive pattern was more sensitive (82%) and specific (90%) than reduced LV ejection fraction and more specific than the Boston criteria and NT-proBNP for the diagnosis of aLVHF. The accuracy of the restrictive pattern in the overall population was 75%, compared with accuracy of 49% for both NT-proBNP and Boston criteria.

Diagnostic accuracy of emergency Doppler echocardiography for identification of acute left ventricular heart failure in patients with acute dyspnea: comparison with Boston criteria and N-terminal prohormone brain natriuretic peptide.
Acad Emerg Med. 2010 Jan;17(1):18-26

Biphasic shocks for AF and Atrial flutter

Based on a study of 453 consecutive patients undergoing their first transthoracic electrical cardioversion for atrial tachyarrhythmias, recommendations were developed to aim at delivering the lowest possible total cumulative energy with ≤2 consecutive shocks using the specific truncated exponential biphasic waveform incorporated in Medtronic Physio-Control devices: they recommend an initial energy setting of 50 J in patients with atrial flutter or atrial tachycardia, of 100 J in patients with atrial fibrillation (AF) of 2 or less days in duration, and of 150 J with AF of more than 2 days in duration. If the initial shock fails to restore sinus rhythm, a rescue shock of 250 J for AFL/AT or of 360 J for AF should be applied to secure the highest possible probability of successful cardioversion for each patient.

Optimization of initial energy for cardioversion of atrial tachyarrhythmias with biphasic shocks

Am J Emerg Med. 2010 Feb;28(2):159-65

Myocardial infarction not so common in LBBB?

An observational cohort study of 7937 ED visits by patients presenting with chest pain or ‘ischemic equivalent’ (shortness of breath for which ACS was considered a possible cause) was done to examine the relationship between left bundle branch block (LBBB) on the ECG and the incidence of acute myocardial infarction (AMI). No difference was observed in the rates of AMI in patients with new or presumed new LBBB, old LBBB, and no LBBB. The authors suggest that this large cohort of undifferentiated ED patients may be more reflective of the true prevalence of AMI in LBBB (7.3% in this study) and question the appropriateness of a liberal fibrinolytic strategy for such patients. Another argument for primary PCI?

Lack of association between left bundle-branch block and acute myocardial infarction in symptomatic ED patients
Am J Emerg Med. 2009 Oct;27(8):916-21

Neonatal prostaglandin E1 and apnoea

The risk of apnoea in neonates requiring prostaglandin E1 infusions for duct-dependent congenital heart disease is well described and often results in the recommendation to intubate prior to transfer. An American study of 202 transported infants on PGE1 shows a higher rate of transport-related complications in those that had been intubated. None of the 73 (36%) unintubated patients required intubation for apneoa during transport. These data are in keeping with a previous Australian study of 300 infants receiving PGE1 in which only 2 of 78 unintubated patients experienced apnoea.
To intubate or not to intubate? Transporting infants on prostaglandin E1
Pediatrics. 2009 Jan;123(1):e25-30

Nurse-delivered prehospital CPAP

A nurse-based pre-hospital care system in Holland describes its experience with pre-hospital CPAP for acute cardiogenic pulmonary oedema. It appears that the simple Boussignac apparatus is straightforward to apply in the ambulance environment. Arguments about lack of outcome studies aside, if it’s necessary to undertake an interhospital transfer of a patient established on CPAP then this might be a relatively straightforward means of doing so.