The "broken heart sydrome": you're likely to have it only once!

Stress cardiomyopathy (SC) is also known as Takotsubo cardiomyopathy. The term transient left ventricular ballooning syndrome has also been used. These terms refer to the same phenomenon. The typical presentation of SC in a patient is a sudden onset of chest pain or heart failure associated with electrocardiographic changes of ST-segment elevation, which is suggestive of anterior ST-segment elevation myocardial infarction. When these patients are assessed, a bulging of the left ventricular apex with a hypercontractile base of the left ventricle is noted. It is this hallmark bulging of the apex with preserved function at the base that characterises this unique syndrome. The possible pathophysiology of its mechanism as well as the different morphological types are discussed.

Circadian rhythm in cardiac arrest: the Singapore experience.

INTRODUCTION: There appears to be a circadian rhythm in the timing of cardiovascular and neurovascular events. The majority of studies have been conducted in western populations. This is the first study to look at the peaks and distribution of out-of-hospital cardiac arrest (OHCA) patients in Singapore. METHODS: The Cardiac Arrest and Resuscitation Epidemiology Studies I and II were prospective observation studies on OHCA in Singapore from October 1, 2001 to October 14, 2004. This study analysed data for patients older than 16 years. All data was collected and recorded as per the Utstein style template. Analysis was done for each of the quadrants of the 24-hour clock: 0001-0600, 0601-1200, 1201-1800 and 1801-2400 hours. RESULTS: Of the 2,428 cases, 2,167 OHCA patients qualified for the final analysis. Their mean ages were in the 60s for all the four quadrants, with a male predominance. The two peaks noted were at 0800 and 1900 hours for cardiac causes of death (n = 1,591), and at 0900 and 2000 hours for non-cardiac causes of death (n = 576). At all times of the day, the majority of OHCA occurred in residences and the bystander cardiopulmonary resuscitation rate ranged from 14.6 to 24.3 percent in the different quadrants of the day. CONCLUSION: OHCA has a bimodal distribution in our local cohort of patients. The information obtained will be utilised for fine-tuning emergency medical services strategies, as we strive to improve our current survival rates for OHCA.

The V-Quick patch versus the standard 12-lead ECG system: time is the essence.

INTRODUCTION: The V-Quick patch template system is compared with the standard 12-lead electrocardiogram (ECG) acquisition technique in this paper. The objectives of the study were: (a) to study and compare the time taken to produce the printed 12-lead ECG and (b) to look at the level of agreement when the ECGs were compared by two blinded, independent assessors. METHODS: One hundred and fifty each of male and female volunteers signed an informed consent form to participate in the clinical study. Nurses were put through a 4-h training session to familiarise themselves with the V-Quick patch system. The timings were measured with a stopwatch with the specific start and end points defined. The final ECG printouts were then compared by two blinded, independent assessors for several set criteria. RESULTS: The V-Quick patch system was proved to be significantly faster than the standard 12-lead system in the acquisition of the ECG in both male and female volunteers. The time taken in male volunteers was also noted to be significantly faster than in female volunteers. CONCLUSION: The two assessors shared a 100% agreement level when comparing the ECGs acquired by both techniques in the same individual (intra-assessor agreement) and when each ECG was read by the two assessors separately (inter-assessor agreement).

Carotid body dysfunction: the possible etiology of non-insulin dependent diabetes mellitus and essential hypertension.

Carotid bodies are monitors of oxygen and glucose delivery to the brain. Faced with the threat of hypoxia or hypoglycemia carotid bodies initiate responses to counter the threat. General corrective action is to improve the perfusion by increasing the arterial blood pressure. Specific corrective actions are to stimulate ventilation to improve oxygen availability or to induce insulin resistance to raise blood glucose levels. Inappropriateness of response caused by misreading of hypoxia as hypoglycemia and hypoglycemia as hypoxia is observed experimentally and clinically. The response to all four types of hypoxia, namely, hypoxic, anemic, histotoxic and ischemic (or stagnant) hypoxia, is stimulation of ventilation and elevation of blood pressure. Ischemia produced by narrowing of the artery to the carotid body activates the carotid bodies. The activation produces hypertension, stimulation of ventilation and insulin resistance that manifests as non-insulin dependent diabetes mellitus. There is epidemiologic and necropsy evidence for the onset of atherosclerotic changes in childhood. Early atherosclerotic changes occurring in the region of carotid arteries and their bifurcation narrows the lumen of the arteries to the carotid bodies and produce hypo-perfusion of the carotid bodies. This ischemic hypoxia is a causative, or at least a permissive factor for hypertension and/or non-insulin dependent diabetes mellitus. It is suggested that neither non-insulin dependent diabetes mellitus causes hypertension nor hypertension causes diabetes mellitus, but both are caused by dysfunctional carotid bodies.

Acute coronary syndrome--factors causing delayed presentation at the Emergency Department.

INTRODUCTION: The aim of the study was to identify factors that contributed to delays in presentation of patients with acute coronary syndrome (ACS) at the Emergency Department (ED). MATERIALS AND METHODS: The study population comprised patients presenting with the signs and symptoms of ACS at the ED of 5 government and restructured hospitals in Singapore from 1 April to 31 May 1999. These patients were interviewed with a structured questionnaire which explored patient demographic data, risk factors, prehospital symptomatology, timing of chest pain, patient response to chest pain and mode of transport to the hospital. RESULTS: Three hundred and two patients who made 307 visits were recruited. More than three-quarters of the patients presented with central or left-sided chest pain. Forty-seven per cent had breathlessness and 42% had sweating. The commonest day of presentation was Monday. It took patients a median time of 2.1 hours from their worst chest pain to arrive at the ED. Past history of diabetes mellitus was associated with a longer delay in presentation. Most of the delay was due to patients awaiting symptom resolution. Forty per cent came by emergency ambulances to hospital. CONCLUSION: Our findings identified various patient characteristics that contributed to delay in presentation to hospital which should be addressed in future education campaigns.

Bystander cardiopulmonary resuscitation in prehospital cardiac arrest patients in Singapore.

INTRODUCTION: The chain of survival emphasizes the importance of the four links associated with survival after cardiac arrest (CA). The involvement of laypersons has been increasing over the years. They have been contributing toward "early access," "early cardiopulmonary resuscitation" (CPR), and, of late, "early defibrillation," with the advent of automated external defibrillators (AEDs). Bystander CPR rates are difficult to assess due to the lack of formal documentation. OBJECTIVE: To assess the bystander CPR rate for CA patients brought to the emergency department (ED) of an urban, tertiary teaching hospital in the central part of Singapore, over a period of 12 months. METHODS: This was a retrospective cohort study carried out from May 1, 1999, to April 30, 2000. "Bystander CPR" refers to an attempt to perform basic CPR by someone who is not part of an organized emergency response system. In general, this refers to the person who witnesses the arrest. RESULTS: There were 155 adult patients with CA who satisfied the inclusion criteria over the 12-month period. The median age was 62.1 +/- 6.4 years, and the majority of patients were brought in by ambulances (126, or 81.3%). There were 142 (91.6%) non-trauma and 13 (8.4%) trauma CAs. Most patients had the CA at home (96, or 61.9%), and the most common initial rhythm at presentation upon the arrival of the paramedics was ventricular fibrillation (VF) (50 patients, or 32.2%). The bystander CPR rate was 20.0% (i.e., 31 of the 155 patients). A total of 32 (20.6%) patients had return of spontaneous circulation (ROSC, defined as the return of a palpable pulse) and 31 (96.9%, or 31/32) of them were those who had some form of bystander CPR performed. Of these 31 who had bystander CPR, four (12.9%) were subsequently admitted to the intensive care unit (ICU), while among those who did not have bystander CPR, all had death pronounced in the ED. Of the four patients admitted to the ICU, three (3 of 4, or 75.0%; or 3 of 155 CA patients, or 1.9%) were subsequently discharged alive from the hospital. CONCLUSION: The bystander CPR rate for prehospital CA was 20.0%. About 12.9% (4 patients) of those who had bystander CPR were admitted to the ICU, compared with none from the group that did not receive any form of bystander CPR. Three patients (1.9% of all prehospital CAs) were discharged alive from the hospital.

Heart emergency room: effective for both geriatric and younger patients.

OBJECTIVES: To compare the 30-day cardiac event rate between patients aged at least 60 years (geriatric group) with those younger than 60 (younger group), who were enrolled in an Emergency department-based chest pain centre management protocol. METHODOLOGY: This was a retrospective, cohort study done at the Centre for Emergency Care at the University of Cincinnati, from 1 Oct 1991 to 31 March 1999 (from Oct 1991 to Dec 1998: 9-hour protocol in use; from Jan 1999 to March 1999: 6-hour protocol in use). Patients, at least 25 years, with the chief complaint of non-traumatic chest pain were eligible for management in the unit. Exclusion criteria included acute ST-elevation or depression > 1 mm in 2 contiguous leads, haemodynamic instability or clinical syndrome consistent with unstable angina. Outcomes studied were disposition and cardiac events at 30-days (defined as acute myocardial infarction, congestive heart failure, ventricular fibrillation / tachycardia arrest, coronary artery bypass surgery or percutaneous transluminal coronary angioplasty). The protocol was the standard of care and enrolled patients underwent continuous ECG and ST-segment trend monitoring, serial CK-MB draws at 0, 3, 6 and 9 hours, followed by either a graded exercise stress test or a sestamibi myocardial perfusion scan (from Oct 1998). With the 6-hour protocol the 9-hour draws were omitted and the GXTdone 3 hours earlier. RESULTS: A total of 2491 patients were enrolled; 304 (12.2%) in the geriatric age-group. The mean age was 66.8+/-5.9 and 41.3+/-8.6 years respectively. There were 133 (43.8%) female patients in the geriatric group and 1170 (53.5%) in the younger group. There were no statistically significant differences between the groups in terms of prevalence of risk factors, but there was significant (p < 0.001) and ECG changes from the baseline (p = 0.0015). The geriatric patients were also not different from the younger ones in terms of GXT positive for ischaemia (10, 5.3% vs 42, 2.7%; p = 0.124), admission rates (61, 20.1% vs 321, 14.7%; p = 0.312), coronary care unit admissions (8, 2.6% vs 63, 2.9%; p = 0.418 and 30-day complication rate (10, 3.6% vs 46, 2.4%; p = 0.303). CONCLUSION: The ED-based chest pain unit represents an effective way for the risk-stratification and management of both geriatric and young patients with low-to-moderate risk of acute coronary events.

Comparison of a 6-hour and 9-hour protocol for evaluation of moderate-to-low risk chest pain patients in an emergency department diagnostic unit.

OBJECTIVE: To compare the 30-day outcomes of patients enrolled in a 6-hour and 9-hour emergency department (ED)-based chest pain centre (CPC) protocol. METHODS: All patients with the chief complaint of chest pain, who were older than 25 years, or with cocaine usage within 96 hours of initial presentation, were eligible for enrolment. Exclusion criteria included acute ST-segment elevation or depression >1 mm in 2 contiguous leads, history of coronary artery disease (CAD), haemodynamic instability or clinical syndromes consistent with unstable angina. Outcomes included ED disposition and cardiac events at 30 days (defined as acute myocardial infarction (AMI), percutaneous trans-luminal coronary angiography (PTCA), coronary artery bypass graft surgery (CABG),ventricular tachycardia or fibrillation (VT/VF) arrest, congestive heart failure (CHF) admission or cardiac-related death). The 9-hour protocol consisted of ST-segment monitoring,serial CK-MB draws at 0, 3,6 and 9 hours as well as a graded exercise test (GXT) prior to ED disposition. The 6-hour protocol eliminated the 9-hour serum marker determination, included cardiac Troponin-I (cTn-I) and allowed a GXT, 3 hours earlier. Follow-up was obtained by medical record review, phone contact, letter and also review of national and state death registries. RESULTS: The 9-hour protocol (October 1991-December 1997) included 2,133 patients and the 6-hour protocol (January 1998- August 1998) had 184 patients enrolled. The 6-hour protocol was not different from the 9-hour one in terms of percentage admissions (9-hour: 310, 14.5%; 6-hour: 33, 17.9%; p=0.213), Coronary Care Unit admission (9-hour: 59, 2.8%; 6-hour: 5, 2.7%; p=0.303) or 30-day cardiac events (9-hour: 38, 1.9%; 6-hour: 2, 1.3%; p=0.605). CONCLUSION: The 6-hour CPC strategy is an effective and safe evaluation method for patients at low to moderate risk for acute coronary syndromes.

Provocative testing for chest pain.

Since the first Chest Pain Center (CPC) was set up in 1981 to speed up the evaluation and treatment of patients with acute myocardial infarction, the original concept has been expanded to include rapid evaluation of chest pain patients with the appropriate streamlining of care and incorporation of the latest in technology. It has also been established that among patients presenting with acute chest pain, a very low-risk group with less than 5% probability of a coronary event can be identified. The recognition of this group could prevent unnecessary admissions, affording more appropriate patient care and improved cost-effectiveness. The efficient management of these chest pain patients requires that there be reductions in: (1) delays in therapy, (2) "soft" admissions, (3) inappropriate dispositions, and (4) cost. With time, provocative testing (PT) for chest pain patients has been brought forward to the frontline. PT methods are now being studied in hundreds of emergency department (ED) patients, followed up over several months to ascertain the predictive value of both positive and negative test results. More and more CPCs are now using PT as part of their management protocol, in terms of decision-making pertaining to prognostification, treatment and disposition. This could be in the form of the ECG graded exercise test (GXT), stress echocardiography (SE) and stress single-photon emission computed tomography (SPECT) radionuclide perfusion imaging. The GXT is fairly widely used currently, SE is gaining popularity and stress radionuclide perfusion imaging will perhaps gain more acceptance as the experience with its use as well as the number of randomized controlled studies increase. As we move into the new millennium, the emergency physicians must familiarize themselves with the latest in the state-of-the-art concepts and technology to render improved, up-to-date and more cost-effective patient care.

Hypotension in acute myocardial infarction patients given streptokinase.

OBJECTIVE: This is a prospective cohort study done over a period of one year to look at hypotension that developed in the local Acute Myocardial Infarction (AMI) patients given Streptokinase (SK). METHOD: Suitable patients with AMI (those with ischaemic chest pain most severe within the last 8 hours, ST-segment elevation and no contraindications) were selected for thrombolysis with SK given as the standard dose of 1.5 mega-units diluted in 100 mls of normal saline and infused over 60 minutes. (Group A). The AMI patients who did not receive SK (Group B), were analysed separately and acted as "controls", as it was not possible to withhold thrombolytic therapy in a group of patients in a completely randomised fashion. The pulse, non-invasive blood pressure and electrocardiogram were monitored and recorded. RESULTS: Of 120 patients analysed, 70 received SK (Group A) and 50 (Group B) did not due to a variety of reasons. There was no statistically significant difference in the sex, age and body weight distribution as well as the initial mean arterial blood pressure (MAP) in the two groups. The MAP showed a statistically significant decrease at 15 minutes (105.6 to 81.4 mmHg, 95%CI: 13.965, 28.178) and 30 minutes (105.6 to 89.6 mmHg, 95%CI: 10.929, 19.814) after the commencement of SK in Group A patients. When analysed separately, the decrease in MAP was also statistically significant at 15 minutes (95%CI: 4.263, 22.014) for those with anterior AMI and both at 15 (95%CI: 19.112, 41.299) and 30 minutes (95%CI: 1.191, 28.716) for those with inferior AMI. There was no statistically significant decrease noted in Group B patients and the door-to-needle time for Group A patients was 37.2+/-6.0 minutes. The SK infusion time for Group A patients who developed hypotension was prolonged to 95.3+/-14.1 minutes. CONCLUSION: Hypotension was more commonly noted in the AMI patients given SK. The MAP tend to decrease in the first 30 minutes after commencing the SK infusion. It is thus possible to conclude that the hypotension was at least partly due to SK and is probably a rate-related phenomenon.

Commotio cordis: an underappreciated cause of sudden death in athletes.

Over the last few years, the recognised cardiovascular risks of sporting activities have been extended to include cardiac arrest resulting from low-energy precordial chest impact produced by projectiles (e.g. baseball) or bodily contact, in the young, healthy and active athlete [also known as commotio cordis (CC)]. However, case reports of CC in European medical literature can be traced back for at least 130 years. CC accounts for a small, but important, subset of sudden death during sporting activities. It is a devastating electrophysiological event in the young athlete, and one which has generated considerable concern, both in the medical profession as well as in the public. The mechanism of sudden death appears to be caused by ventricular fibrillation, which occurs when the chest impact is delivered within a narrow, electrically vulnerable portion of the cardiac cycle, that is, during repolarisation, just before the peak of the T wave. Resuscitation of these victims is possible with prompt cardiopulmonary resuscitation and defibrillation. Preventive measures, such as the use of age-appropriate safety baseballs and suitably designed chest wall protection, may reduce the risk of sudden death and, thus, make the athletic field a safer place for young athletes.

Chest impedance: characteristics of local patients.

The Pre-hospital Defibrillation Program in Singapore has in some cases demonstrated a lower amplitude of Ventricular Fibrillation (VF) than considered the norm. The Electrode Skin Impedance (ESI) refers to the skin impedance determined between two electrodes placed at specific positions on the body surface. The objective of this prospective study was to measure the ESI of patients at 5 Hz and 2 kHz frequencies, and assess its change with time from the application of electrodes, the difference between the ESI at two different sets of electrode placement positions and correlation with patient factors. Patients who were 25 years or older and not critically ill had their ESI measured with a modified Heart-Save 911 defibrillator, using signal frequencies at 5 Hz and 2 kHz, at 10 seconds, 1 and 2 minutes after electrodes application. Two sets of positions were used; Position 1 where an electrode is placed in the right infra-clavicular region and another just lateral to the apex beat on the left and Position 2, which represents the mirror image of Position 1. 36 each of male and female patients were studied. The mean age and weight were 59.9 +/- 13.5 years and 56.8 +/- 24.1 kg respectively. There was no significant correlation between the ESI and patients' body weight or sex. However, there was a significant decrease in the ESI with time from application of electrodes at both Positions (p < 0.05) with the two different frequencies. The ESI was lower when measured at lower frequencies and higher when taken at higher frequencies, but there was no statistically significant difference between the two mirror-image positions used. Thus, with lower frequency, the ECG amplitude of VF recorded on the automated external defibrillator could be enhanced.

Delays in the EMS response to and the evacuation of patients in high-rise buildings in Singapore.

BACKGROUND: Singapore is a highly urbanized and cosmopolitan city situated at the crossroads of Southeast Asia. High-rise buildings and "vertical living" are common, and the city serves as a major business, financial, and industrial hub in the region. More than 80% of the population live in high-rise apartments. This poses unique problems and challenges for emergency ambulance services personnel in the access to and evacuation of patients. OBJECTIVE: To estimate the arrival-to-patient contact delay when accessing patients in high-rise buildings and evacuating them to the hospital, compared with accessing patients in ground-level premises. METHODS: This was a prospective study carried out from February 2 to March 1, 1998, for emergency calls from two of the busiest fire stations. The first 150 consecutive cases were enrolled into each of the two groups. Cases of road traffic accidents were excluded because these did not require the crew to get into a building. The times were clocked by one of the paramedics, using a stopwatch. A high-rise building was defined as one where the crew had to ascend at least one flight of stairs. A ground-level building did not involve any stair climbing. We set forth to determine whether the interval between the following was statistically significant when comparing high-rise vs ground-level premises: 1) time when the ambulance arrives at the scene (taken as the time when the driver turns the engine off) and time of arrival at the patient's side; 2) time of leaving the dwelling with the patient and time when the ambulance starts its journey to the hospital (taken as the time when the driver starts the engine). Data analysis was done with the use of SPSS, and the one-tailed unpaired Student's t-test was used for significance testing, with the alpha error rate set at 0.05. Results. One hundred fifty runs were analyzed for each group. The mean delay from arrival to patient contact was 2.49 +/- 0.98 minutes for the high-rise group compared with 1.02 +/- 1.41 minutes for the ground-level group (difference was statistically significant with 95% CI: 1.20, 1.74 minutes; p = 0.0106). The mean delays from the time of leaving the building with the patient to the time when the ambulance turned its engine on to start its journey to the hospital were 3.24 +/- 1.58 minutes and 1.27 +/- 0.71 minutes for the two groups, respectively (difference was statistically significant with 95% CI: 1.68, 2.04 minutes; p = 0.0098). CONCLUSION: There were significant delays present when accessing patients in high-rise buildings and evacuating them to the hospital. Modification to buildings and increasing public awareness and education have been suggested to help minimize these delays.

The short-stay emergency observation ward is here to stay.

The traditional venue for the management of most medical and surgical emergencies has been the in-hospital environment. It is only when patients have been fully evaluated and treated that they are discharged. The increasing cost of hospital stay and burgeoning cost of health care are forcing the medical profession to consider options where illnesses can be managed on a more ambulatory basis. The objective of this study was to assess the volume, characteristics, and disposition of emergency department (ED) patients who were managed in the Short-Stay Emergency Observation Ward (SSEOW). A retrospective study of all patients managed in the SSEOW at the Singapore General Hospital (SGH) from July 1 to December 31, 1997 was conducted. The ED case-records of all observed patients were reviewed. Demographic data as well as information on duration of stay, provisional diagnoses, investigations performed, treatment rendered, and disposition were collected. A total of 114,586 patients were seen at the ED during the study period. There were 9,126 (7.9%) patients who were observed and 1,756 (19.2% of observed or 1.5% of total ED attendance) were subsequently admitted. The median duration of observation was 5.6 +/- 9.2 hours. The hospitalization rate for male and female patients was almost equal (19.2% versus 19.3%) and those 60 years and older (3,559 or 39.00%) had the highest hospitalization rate (28.0%). The higher the triage priority, the more likely the patient was to be observed and subsequently admitted. Most were observed between 2 to 4 hours (3,288 or 36.0%) and the largest group comprised of those with abdominal complaints (4,115 or 45.1%). Patients with alcohol-related problems were observed the longest (6.7 + 9.8 hours) but had the lowest hospitalization rate (2.6%). The SSEOW allowed a 6.4% savings to direct inpatient admission at SGH. The SSEOW represent a management area for the delivery of short-term and diagnostic care on an ambulatory basis. It is accessible, safe and effective in reducing adions.

Changes in chest electrode impedance.

The Prehospital Defibrillation Program in Singapore has in some cases shown a lower amplitude of ventricular fibrillation (VF) than considered the norm. The electrode skin impedance (ESI) refers to the skin impedance determined between two electrodes placed at specific positions on the body surface. The objective of this prospective study was to measure the ESI of patients at 5 Hz and 2 kHz frequencies, and assess its change with time from the application of electrodes, the difference between the ESI at two different sets of electrode placement positions, and correlation with patient factors. Patients who were 25 years or older and not critically ill had their ESI measured with a modified Heart-Save 911 defibrillator, using signal frequencies at 5 Hz and 2 kHz, at 10 seconds, 1 and 2 minutes after electrodes application. Two sets of positions were used; position 1 where an electrode is placed in the right subclavicular region and another just lateral to the apex beat on the left and position 2, which represents the mirror-image of position 1. Thirty-six each of men and women patients were studied. The mean age and weight were 59.9 +/- 13.5 years and 56.8 +/- 24.1 kg respectively. There was no significant correlation between the ESI and patients' body weight or sex. However, there was a significant decrease in the ESI with time from application of electrodes at both positions (P < .05) with the two different frequencies. The ESI was lower when measured at lower frequencies and higher when taken at higher frequencies, but there was no statistically significant difference between the two mirror-image positions used. Thus, with lower frequency, the electrocardiogram amplitude of VF recorded on the automated external defibrillator could be enhanced.