Biomedical subjects
Publications and source records attributed to W J Brady.
Artefact on electrocardiograms is a source of potential misdiagnosis and may lead to patients' receiving unnecessary treatments. This article present two cases that illustrate this problem, and will briefly look at known internal and external causes of artefact.
Wolff-Parkinson-White syndrome is not uncommon in the emergency department. Its early recognition and initial treatment allows rapid restoration to sinus rhythm. Prompt referral to cardiology is essential for risk stratification through electrophysiological studies.
Explore the source record for details and available documents.
The widely recognized benefits of early diagnosis and treatment of acute myocardial infarction (AMI) have only emphasized the importance of emergency physician (EP) competence in electrocardiographic interpretation. As such, the EP must be an expert in the interpretation of the electrocardiogram (ECG) in the emergency department chest pain center patient. The ECG is a powerful clinical tool used in the evaluation of patients, assisting in making the diagnosis of AMI and other syndromes, selecting appropriate therapies (including thrombolysis and primary angioplasty), securing the location of an adequate inpatient disposition, and predicting the risk of cardiovascular complications and death. This article will discuss the appropriate uses of the ECG in the patient with possible or confirmed AMI and review the typical electrocardiographic findings of AMI, diagnostically confounding patterns, mimickers of infarction, and new techniques.
The accurate assessment and triage of patients with potential ACS is a complex decision-making process based on information that is not entirely reliable. The knowledgeable EP recognizes that assessment of patients with chest pain requires an understanding of the various clinical presentations of ACS and high-risk patient types, as well as careful use of the available modalities to diagnose these syndromes efficiently while incurring minimal risk to the patients safety. The busy EP is faced with sick patients with chest pain daily, so that it behoove anyone in emergency medicine to familiarize themselves with these diagnostic pitfalls.
Bradyarrhythmias arising in the setting of myocardial infarction occur in a significant minority of patients with AMI. In the majority of cases, these abnormalities are owing to myocardial ischemia or infarction with necrosis of the cardiac pacemaker sites and/or conduction system. Other factors responsible for these bradyarrhythmias include altered autonomic influence, systemic hypoxia, electrolyte disturbances, acid-based disorders, and complications of various medical therapies. This article will focus on not only the diagnosis and management of these rhythm disturbances, but also on the pathophysiology of the arrhythmias.
Toxicity from the digitalis family of cardiac glycoside medications remains common. Successful treatment depends on early recognition; however, the diagnosis of potentially life-threatening toxicity remains difficult because the clinical presentation is often nonspecific and subtle. The hallmark of cardiac toxicity is increased automaticity coupled with concomitant conduction delay. Though no single dysrhythmia is always present, certain aberrations such as frequent premature ventricular beats, bradydysrhythmias, paroxysmal atrial tachycardia with block, junctional tachycardia, and bidirectional ventricular tachycardia are common. Treatment depends on the clinical condition rather than serum drug level. Management varies from temporary withdrawal of the medication to administration of digoxin-specific Fab fragments for life-threatening cardiovascular compromise.
Posterior myocardial infarction (PMI) refers to infarction of the posterior wall of the left ventricle. Although often associated with inferior and lateral myocardial infarctions, detection of acute PMI is difficult because the standard 12-lead electrocardiogram does not adequately image the posterior wall of the left ventricle. We review the findings on 12-lead electrocardiogram with PMI, as well as discuss the utility of additional electrocardiographic leads in the diagnosis of PMI.
The electrocardiographic findings associated with pulmonary embolism have been well described in the medical literature for over 50 years. These abnormalities include changes in rhythm, QRS axis, and morphology, particularly in the QRS and T waves. Such findings may reflect hemodynamic changes, such as right heart strain, as well as myocardial ischemia associated with the disease. Although certain findings may correlate with the severity of pulmonary embolism, the overall utility of the electrocardiogram is limited due to the variable presence, frequency, and transient nature of most of the abnormalities associated with the disease.
The objective of this study was to determine the electrocardiographic diagnoses of chest pain patients with ST segment elevation (STE) on the 12-lead electrocardiogram (ECG). This study was a retrospective ECG review of adult chest pain patients in a university hospital emergency department (ED) over a 3-month period (January 1, 1996 to March 31, 1996). STE was determined if the ST segment was elevated >/=1 mm in the limb leads and >/=2 mm in the precordial leads in at least two anatomically contiguous leads. Results showed 902 patients who met entry criteria and of whom 202 (22.4%) had STE. Thirty-one (15%) patients had STE acute myocardial infarction (AMI) as the final hospital diagnosis which caused the STE; 171 (85%) patients with STE had non-AMI diagnosis responsible for the ST segment elevation, including left ventricular hypertrophy (LVH) 51 (25%), left bundle branch block (LBBB) 31 (15%), benign early repolarization (BER) 25 (12%), right bundle branch block 10 (5%), nonspecific bundle branch block 10 (5%), left ventricular aneurysm 5 (3%), acute pericarditis 2 (1%), ventricular paced rhythm 2 (1%), and undefined ST segment elevation 35 (17%). Forty-four patients had AMI as the final diagnosis of whom 31 showed STE on presentation to the ED. In 2 of 31 (6%) cases of STE AMI, the ST segment waveform was atypical for acute infarction. We concluded that AMI is not the most common cause of STE in ED chest pain patients. LVH is most often responsible for electrocardiographic STE followed by AMI and LBBB which occur at equal frequencies.
Atropine has also been suggested to potentially worsen the ischemic situation in patients who are in the midst of acute coronary ischemia. We report the case of a female patient with ischemic chest pain and third degree atrioventricular block who developed acute myocardial infarction (AMI) immediately after atropine administration. The use of atropine in this instance remains a reasonable option and should be strongly considered-despite this apparent complication. Undoubtedly in some cases, acute ischemia is intensified by hypoperfusion attributable to vagally mediated bradyarrhythmia; atropine is the antidote for such situations. An awareness of this potential adverse reaction coupled with a prudent selection of candidates for atropine therapy will show the risk/benefit ratio in each individual patient and, therefore, guide the clinician.
The objective of this study was to determine if consideration for percutaneous transluminal coronary angioplasty (PTCA) delays administration of thrombolytic therapy in acute myocardial infarction (AMI) patients. Retrospective medical record review of patients ultimately diagnosed with AMI who presented to the ED with chest pain and ST segment elevation on the electrocardiogram; these patients also received acute reperfusion therapy (PTCA or thrombolytic agent). AMI was diagnosed by abnormal elevations in the creatinine phosphokinase MB fraction. The study period covered 2 years (July 1, 1994 to June 30, 1996) in a university hospital ED with an annual volume of 60,000 patient-visits. The use of reperfusion therapies, time intervals, and times of presentation were recorded. Patients were divided into two groups based on cardiac catheterization laboratory (CATH) availability: (group I, CATH currently in operation, Monday to Friday, 7 am to 7 pm and group II, CATH currently not in-operation, all other times). Fifty-two patients with AMI met entry criteria. Patients were treated with thrombolytic therapy in 25 cases; PTCA in 27 cases. Patients received thrombolytic agents within statistically equivalent time intervals regardless of the period of presentation; time to thrombolytic therapy for group I patients was 38 +/- 16 minutes compared with 36 +/- 26 minutes for group II patients (P =. 891). A trend toward significance was noted in the use of PTCA compared with thrombolytic agent; Group I patients were more often treated with PTCA (19) compared with group II patients (11, P =.067). Patients were more rapidly treated with PTCA during CATH operation; the mean time to PTCA for group I patients was 73.5 minutes compared with PTCA for group II patients with 107.8 minutes (P =.033). The consideration for PTCA did not significantly delay the administration of thrombolytic therapy at the study site institution. PTCA was initiated more rapidly in patients presenting with AMI during hours of CATH operation.
Lisfranc fracture-dislocation of the foot is an injury that carries a high incidence of chronic pain and disability. Its emergency department presentation can be subtle, and more frequent than previously believed. This review article examines the clinical presentation, historical factors, diagnostic techniques, and management options applicable to the emergency practitioner.
The objective of this study was to investigate the outcome and rate of symptomatic recurrence of paroxysmal supraventricular tachycardia (PSVT) in an emergency department (ED) patient population, after ED management and disposition. A retrospective descriptive review of ED records and state death registry was performed. The study took place at a University hospital ED with 60,000 annual patient volume. The subjects were all patients presenting to the ED in PSVT from January 1993 to December 1996. One hundred eleven patients met entry criteria. The mean age was 53 years, 49% were men, and 51% were women. EMS was used by 47 (42%) patients. Ten of these patients who used the EMS system had an unstable event in the prehospital setting. Eleven patients had unstable events once in the ED. ED therapy given (with number of successes in parentheses) included: Adenosine 48 (41), vagal maneuvers 44 (22), calcium channel blockers 22 (14), beta-blockers 10 (4), and electrical cardioversion 5 (1). Twenty-six patients (23%) spontaneously converted to normal sinus rhythm (NSR). Seventy-nine (71%) patients were discharged from the ED. Mean age for this group was 49 years, and the mean ED stay for this group was 3.8 hours. Three patients (4%) in this group had a recurrence of their SVT after discharge. These patients all had recurrence within 24 hours, and none had an unstable event associated with their recurrence. Thirty-two (29%) patients were admitted to the hospital, with 3 (9%) going to a monitored floor, and 29 (91%) going to an intensive care unit. Mean age for this group was 65 years. Twenty-one of these 32 admitted patients (65%) required continued in-hospital therapy once admitted for their arrhythmia. Six of the 32 admitted patients (19%) had recurrent PSVT in the hospital, with 1 episode of instability. Recurrence of PSVT was more likely to occur among those admitted (P <.05), in older patients (P<.01), and in those with a history of cardiovascular disease (P <.01). No deaths were recorded in either group. Most patients with PSVT can be safely discharged from the ED after short-term observation if therapy produces prompt conversion to NSR. PSVT recurrence is relatively uncommon and usually occurs within 24 hours of ED presentation. PSVT recurrence occurs more often in the elderly and in those with established cardiac disease.
Closed tendon injuries of the hand are frequently seen in the emergency department. Unlike open tendon injuries, however, these injuries are often missed on initial presentation. Early recognition and treatment can decrease the pain, dysfunction, and long-term sequelae associated with these injuries. This review article examines the clinical presentation, historical factors, diagnostic techniques, and management options applicable to the emergency practitioner. Injuries discussed include rupture of the flexor digitorum profundus, mallet finger, central slip rupture, extensor hood rupture, and ulnar collateral ligament injury.
Occult dislocations at and around the lunate can accompany wrist trauma. When left unrecognized and untreated, these injuries lead to a high incidence of long-term functional disability and chronic pain. Emergency medicine practitioners need to be vigilant for both lunate and perilunate dislocations. This review article examines the clinical presentation, diagnostic techniques, and management options applicable to the emergency practitioner.
Traditionally, ST segment depression has been associated with acute coronary syndromes; this electrocardiographic pattern may also be found in patients with nonischemic events, such as left bundle branch block (LBBB), left ventricular hypertrophy (LVH), and those with therapeutic digitalis levels. Using the ECG as an adjunct in distinguishing those patients with acute coronary syndromes from those with more "benign," nonacute causes of STSD will obviously lead to divergent treatment and management plans. The following cases illustrate the use the ECG in patients presenting with chest pain and electrocardiographic ST segment depression attributable to an ACS, LVH, LBBB, or digitalis.
Occult dislocations at the wrist and elbow frequently accompany forearm fractures. When left unrecognized and untreated, these injuries lead to a high incidence of long-term functional disability and chronic pain. Emergency medicine practitioners need to be vigilant for both Galeazzi (distal radius fracture with radioulnar joint disruption), and Monteggia (proximal ulna fracture with radial head dislocation) fracture-dislocations. This review article examines the clinical presentation, diagnostic techniques, and management options applicable to the emergency practitioner.