Mary G. Carey

Predictors of pre-hospital delay among patients with acute myocardial infarction

OBJECTIVE To evaluate current literature on predictors of pre-hospital delay among patients with acute myocardial infarction (AMI). METHODS Medline, CINHAL, and Psych Info databases were searched using keywords: attitude to illness/health, health beliefs, help/health seeking behavior, health behavior, psychosocial factors, treatment delay, socioeconomic factors, time factors, pre-hospital delay, and symptoms. These keywords were combined with AMI to identify literature published during 1995-2008. RESULTS Twenty-six data-based research articles were identified. Delay varied across literature and median pre-hospital delay was often reported due to distribution skewness resulting from extremely prolonged values (1.5-15.2h). Six categories of predictors influenced pre-hospital delay; socio-demographic, symptom onset context, cognitive, affective/psychological, behavioral, and clinical factors. Pre-hospital delay was shortest when the decision to seek healthcare was facilitated by family members or coworkers and when symptoms suggestive of heart attack were continuous and severe. CONCLUSION AND PRACTICE IMPLICATIONS Developing interventions programs to reduce pre-hospital delay for high-risk patients is warranted. Because decision delay is the only modifiable part by intervention, it is recommended that future investigations and interventions attend to decision time as the primary variable of interest instead of combining it with transportation time. Moreover, content of patient education need to emphasize on symptom awareness and recognition, and prompt and proper patient actions for optimum results. Also, in order to eliminate sampling bias resulting from investigating surviving AMI patients, it is recommended that future studies incorporate data from both surviving and surrogates of non-surviving AMI patients.

A Low-Glycemic Nutritional Fitness Program to Reverse Metabolic Syndrome in Professional Firefighters: Results of a Pilot Study

Background:The risk for cardiovascular events is higher for those with metabolic syndrome (MetS), and it is known that firefighters have a 4-fold risk for cardiovascular events. The purpose of this study was to quantify MetS prevalence and evaluate the effect of a low-glycemic nutritional fitness program on the reduction of MetS risk factors among firefighters. Methods:Professional firefighters were screened for MetS then enrolled in a low-glycemic nutritional fitness program for a 12-week period. Anthropometric and physiological measurements were obtained at the start and end of the program. Subjects with 3 or more of the following were positive for MetS: waist-40-inches or greater (men) or 35 inches or greater (women), blood pressure 135 mm Hg or greater (systole) or 85 mm Hg or greater (diastole), fasting blood sugar 100 mg/dL or greater, triglycerides 150 mg/dL or greater, and high-density lipoproteins less than 40 mg/dL (men) or less than 50 mg/dL (women). Weekly sessions provided low-glycemic nutrition instruction, fitness training, and evaluation of individual progress. Results:Seventy-five firefighters (aged 42 [SD, 8] years, mostly white men) had a total MetS prevalence of 46.7% (P < .05 vs normal population). One platoon (10 men, aged 48 [SD, 5] years) was enrolled in the 12-week program. Most (7/10) had MetS at the baseline, but this prevalence decreased significantly after 12 weeks to 3 subjects (P = .02). On average, subjects had 3.2 (SD, 1.6) versus 1.9 (SD, 1.7) MetS risk factors (P < .01) at baseline and the 12-week interval, respectively. Conclusions:The prevalence of MetS and MetS risk factors is higher among professional firefighters compared with the general population. A short-duration, low-glycemic fitness program can successfully improve anthropometric and physiological measures and reduce the prevalence of MetS.

Increased T wave complexity can indicate subclinical myocardial ischemia in asymptomatic adults

BACKGROUND Altered ventricular repolarization and cardiovascular mortality are closely correlated, and recent novel findings show that a distorted T wave loop morphology is also strongly correlated with subsequent onset of myocardial infarction among patients with stable angina. Therefore, we hypothesized that an abnormal T wave complexity ratio (CR) can indicate vulnerability to myocardial ischemia in asymptomatic, apparently healthy adults. METHODS Healthy firefighters were enrolled in the current investigation where they completed symptom-limited, graded exercise treadmill testing (ETT) and 24-hour Holter electrocardiogram recording. The CR was automatically calculated using principal component analysis of the high-resolution Holter electrocardiogram signal then averaged over 24 hours (CR(24h)). End points were manually analyzed from the ETT; recordings revealing horizontal ST-segment depression (≥ 1 mm) in 2 or more leads for at least 1 minute during the peak of exercise were considered indicators of myocardial ischemia. RESULTS One hundred four firefighters (age, 44 ± 8 years; 96% men) completed both ETT and Holter recording. Firefighters with positive end points (n = 34, or 33%) had higher CR(24h) compared with those with negative end points (0.14 ± 0.06 vs 0.09 ± 0.04, P < .01); there were no demographic differences between the 2 groups. After controlling for age, smoking status, hypertension, and obesity, an abnormal CR(24h) (≥ 20%) significantly predicted exercise-induced myocardial ischemia (odds ratio, 4.6; P = .01). CONCLUSIONS Increased T wave CR(24h) can predict myocardial ischemia in asymptomatic middle-age adults; this suggests that the distorted T wave loop morphology can reflect an altered ventricular repolarization caused by prolonged subclinical myocardial ischemia possibly caused by early coronary artery disease.

American heart association: Council on cardiovascular nursing

According to the American Heart Association (AHA), physical inactivity is an important independent risk factor for coronary heart disease. In 2007, only 30.8% of persons engaged in 30 minutes or more of moderate physical activity per weekVthe level sufficient to lower the risk of coronary heart disease. Similarly, only 21.9% of men and 17.5% of women reported strength training twice or more often per week. In children aged 6 to 11 years, 42% met the recommendation to accumulate at least 1 hour of physical activity on most days of the week. Physical activity levels among adolescents dropped to 12% for boys and 3% for girls in those aged 12 to 15 years. In reality, physical activity declines substantially throughout the entire life span. These declines underscore the need for additional programs to increase the physical activity levels among all age groups. Several organizations have recently published guidelines for physical activity (Table 1). Several strategies proposed by the AHA in meeting these guidelines and treating physical inactivity are lifestyle modification through counseling, education, and outreach efforts. Studies of the beneficial effects of healthy lifestyles on cardiovascular outcomes highlight the need for intensive primary and secondary prevention efforts in middle age and beyond to improve healthy longevity and quality of life. People who adhere to the physical activity guidelines should be able to improve their physical functioning within 3 to 6 months and achieve the health benefits of physical activity. Health benefits include (http:// www.americanheart.org):

The Selvester QRS Score is more accurate than Q waves and fragmented QRS complexes using the Mason-Likar configuration in estimating infarct volume in patients with ischemic cardiomyopathy

Infarct volume independently predicts cardiovascular events. Fragmented QRS complexes (fQRS) may complement Q waves for identifying infarction; however, their utility in advanced coronary disease is unknown. We tested whether fQRS could improve the electrocardiographic prediction of infarct volume by positron emission tomography in 138 patients with ischemic cardiomyopathy (ejection fraction, 0.27 +/- 0.09). Indices of infarction (pathologic Q waves, fQRS, and Selvester QRS Score) were analyzed by blinded observers. In patients with QRS duration less than 120 milliseconds, number of leads with pathologic Q waves (mean, 1.6 +/- 1.7) correlated weakly with infarct volume (r = 0.30, P < .05). Adding fQRS increased the number of affected leads (3.6 +/- 2.5), but the significant correlation with infarct volume was lost (r = 0.02, P = .10). Selvester Score was the most accurate (mean, 5.9 +/- 4.9 points; r = 0.49; P < .001). Fragmented QRS was not predictive of infarct size in patients with QRS duration of at least 120 milliseconds (r = 0.02, P = .19). Thus, in ischemic cardiomyopathy, consideration of fQRS complexes does not improve Q wave prediction of infarct volume; but Selvester Score was more accurate.

Novel technical solutions for wireless ECG transmission & analysis in the age of the internet cloud ☆

Current guidelines recommend early reperfusion therapy for ST-elevation myocardial infarction (STEMI) within 90 min of first medical encounter. Telecardiology entails the use of advanced communication technologies to transmit the prehospital 12-lead electrocardiogram (ECG) to offsite cardiologists for early triage to the cath lab; which has been shown to dramatically reduce door-to-balloon time and total mortality. However, hospitals often find adopting ECG transmission technologies very challenging. The current review identifies seven major technical challenges of prehospital ECG transmission, including: paramedics inconvenience and transport delay; signal noise and interpretation errors; equipment malfunction and transmission failure; reliability of mobile phone networks; lack of compliance with the standards of digital ECG formats; poor integration with electronic medical records; and costly hardware and software pre-requisite installation. Current and potential solutions to address each of these technical challenges are discussed in details and include: automated ECG transmission protocols; annotatable waveform-based ECGs; optimal routing solutions; and the use of cloud computing systems rather than vendor-specific processing stations. Nevertheless, strategies to monitor transmission effectiveness and patient outcomes are essential to sustain initial gains of implementing ECG transmission technologies.

Clinical Utility of Ventricular Repolarization Dispersion for Real‐Time Detection of Non‐ST Elevation Myocardial Infarction in Emergency Departments

Background A specific electrocardiographic (ECG) marker of ischemia would greatly improve the speed and accuracy of detecting and treating non-ST elevation myocardial infarction (NSTEMI). We hypothesize that ischemia induces ventricular repolarization dispersion (VRD), altering the T-wave before any ST segment deviation. We sought to evaluate the clinical utility of VRD to (1) detect NSTEMI cases in the emergency department (ED) and (2) identify NSTEMI cases at high risk for in-hospital major adverse cardiac events (MACEs). Methods and Results We continuously recorded 12-lead Holter ECGs from chest pain patients upon their arrival to the ED. VRD was quantified using principal component analysis of the 12-lead ECG to compute a T-wave complexity ratio (ie, ratio of second to first eigenvectors of repolarization). Clinical outcomes were obtained from hospital records. The sample was composed mainly of older males (n=369; ages 63±12 years; 63% males), and 92 (25%) had NSTEMI and 26 (7%) had MACEs. Baseline T-wave complexity ratio modestly correlated with peak troponin levels (r=0.41; P<0.001) and was a good classifier of NSTEMI events (area under the curve=0.70). An increased T-wave complexity ratio on the presenting ECG was strongly associated with NSTEMI (odds ratio [OR]=3.8 [2.1 to 5.8]) and in-hospital MACE (OR=8.2 [3.1 to 21.5]). Conclusions A simple measure of global VRD on the presenting 12-lead ECG correlates with ischemic myocardial injury and can discriminate NSTEMI cases very early during evaluation. Prospective studies should validate these findings and test whether VRD can guide therapy.

High Resolution 12-lead Electrocardiograms of On-Duty Professional Firefighters: A Pilot Feasibility Study

Background: Cardiovascular deaths among on-duty firefighters are high-double that of police officers and quadruple that of first responders. The aim of this pilot study was to establish the feasibility of obtaining high-resolution electrocardiograms (ECGs) of on-duty firefighters useful for detecting ECG predictors for cardiac events. Methods: Twenty-eight professional firefighters (age, 46 ± 6 years) wore a 12-lead ECG Holter for 24 hours (16 hours while on duty and 8 hours postduty). All activities, including fire and medical calls, were monitored. Results: On average, the recordings were 92% analyzable. All were in the sinus, with a heart rate of 80 ± 11 beats per minute (range, 35-188 beats per minute). The average rr50 over the 24-hour Holter study was 6.2% ± 6% (range, 1%-23%) and the average square root mean square successive differences (RMSSD), NN intervals was 81 ± 55 (range, 24-209). Using the QRS/Tsimple formula, the average spatial QRS-T angle was 104° ± 17° (range, 78°-132°). Nonsustained ventricular tachycardia occurred irrespective of activity or time of day in 3 (11%) firefighters, which was significantly higher than in comparable normal populations (P < .05). Conclusions: This preliminary work demonstrates that it is feasible to obtain high-resolution ECGs during firefighting activities and further points to the high prevalence of dysrhythmias among firefighters. The strategy of continuous field monitoring of firefighters could provide new insight into the association between their specific professional lifestyle and high cardiac risks.

A research method for detecting transient myocardial ischemia in patients with suspected acute coronary syndrome using continuous ST-segment analysis.

Each year, an estimated 785,000 Americans will have a new coronary attack, or acute coronary syndrome (ACS). The pathophysiology of ACS involves rupture of an atherosclerotic plaque; hence, treatment is aimed at plaque stabilization in order to prevent cellular death. However, there is considerable debate among clinicians, about which treatment pathway is best: early invasive using percutaneous coronary intervention (PCI/stent) when indicated or a conservative approach (i.e., medication only with PCI/stent if recurrent symptoms occur). There are three types of ACS: ST elevation myocardial infarction (STEMI), non-ST elevation MI (NSTEMI), and unstable angina (UA). Among the three types, NSTEMI/UA is nearly four times as common as STEMI. Treatment decisions for NSTEMI/UA are based largely on symptoms and resting or exercise electrocardiograms (ECG). However, because of the dynamic and unpredictable nature of the atherosclerotic plaque, these methods often under detect myocardial ischemia because symptoms are unreliable, and/or continuous ECG monitoring was not utilized. Continuous 12-lead ECG monitoring, which is both inexpensive and non-invasive, can identify transient episodes of myocardial ischemia, a precursor to MI, even when asymptomatic. However, continuous 12-lead ECG monitoring is not usual hospital practice; rather, only two leads are typically monitored. Information obtained with 12-lead ECG monitoring might provide useful information for deciding the best ACS treatment. Purpose. Therefore, using 12-lead ECG monitoring, the COMPARE Study (electroCardiographic evaluatiOn of ischeMia comParing invAsive to phaRmacological trEatment) was designed to assess the frequency and clinical consequences of transient myocardial ischemia, in patients with NSTEMI/UA treated with either early invasive PCI/stent or those managed conservatively (medications or PCI/stent following recurrent symptoms). The purpose of this manuscript is to describe the methodology used in the COMPARE Study. Method. Permission to proceed with this study was obtained from the Institutional Review Board of the hospital and the university. Research nurses identify hospitalized patients from the emergency department and telemetry unit with suspected ACS. Once consented, a 12-lead ECG Holter monitor is applied, and remains in place during the patients entire hospital stay. Patients are also maintained on the routine bedside ECG monitoring system per hospital protocol. Off-line ECG analysis is done using sophisticated software and careful human oversight.

Electrocardiogram-based predictors of clinical outcomes: a meta-analysis of the prognostic value of ventricular repolarization.

OBJECTIVES To estimate age- and sex-specific prognostic values of eight electrocardiographic repolarization descriptors to predict various mortality endpoints. BACKGROUND Using electrocardiographic markers for risk stratification is well studied; however, the prognostic value of many markers is controversial, and their clinical utility remains debatable. No meta-analyses exist that address the prognostic value of ECG markers. METHODS Data were synthesized from 106 primary studies using a random-effect variance model. Age and sex subgroups were analyzed using sensitivity analysis. RESULTS Four classic (i.e., duration, amplitude, inversion, and ST-T changes) and four novel (i.e., axis, loop, wavefront direction, and waveform complexity) repolarization descriptors were studied. These novel descriptors were particularly useful in predicting sudden death. Abnormal repolarization duration, vectors, and loops have greater impact on negative cardiovascular outcomes in women compared to men; additionally, ischemic repolarization changes have greater impact on negative cardiovascular outcomes in younger versus older adults. CONCLUSIONS Assessing repolarization abnormalities is particularly helpful in women and younger adults. Researchers need to further explore the clinical utility of these abnormalities in management algorithms.