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Biomedical subjects

Victor F Froelicher

Publications and source records attributed to Victor F Froelicher.

At least 19 recordsLinked to original sources
PubMed2006

Prognostic Significance of Quantitative QRS Duration.

BACKGROUND: Although QRS duration is known to be a predictor of mortality in patients with left ventricular dysfunction, our purpose was to evaluate the prognostic power of computer-measured QRS duration in a general medical population. METHODS: Analyses were performed on the first electrocardiogram digitally recorded on 46,933 consecutive patients at the Palo Alto Veterans Affairs Medical Center between 1987 and 2000. Patients with electrocardiograms exhibiting Wolff-Parkinson-White were excluded (n = 44), and those with bundle branch block or electronic pacing were considered separately, leaving 44,280 patients for analysis (mean age 56 +/- 15 years; 90% were males). There were 3659 (8.3%) cardiovascular deaths (mean follow-up of 6.0 +/- 3.8 years). RESULTS: A survival plot showed significant separation according to a QRS duration score. After adjustment in the Cox model for age, gender, and heart rate, the QRS duration score was a strong independent predictor of cardiovascular mortality. For every 10-ms increase in QRS duration, there was an 18% increase in cardiovascular risk. The results were similar in patients with an abnormal electrocardiogram, a bundle branch block, and a paced rhythm. CONCLUSION: Quantitative QRS duration was a significant and independent predictor of cardiovascular mortality in a general medical population.

Adult↗
PubMed2005

Prognostic importance of isolated T-wave abnormalities.

Computerized electrocardiograms recorded on 46,950 male veterans were analyzed to demonstrate the prognostic value of T-wave amplitude in a general medical population. There were 3,926 cardiovascular deaths over 6 years. Multivariate survival analysis allowed the development of a T-wave amplitude graphic that provides clinicians with a simple method of estimating the relative risk for cardiovascular mortality from T-wave amplitude in limb lead I.

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PubMed2005

Electrocardiographic damage scores and cardiovascular mortality.

BACKGROUND: A number of electrocardiogram (ECG) classification systems have been developed to estimate cardiac injury, infarct size, and left ventricular function. Although many studies have documented an association between clinical, imaging, and autopsy data, few have evaluated their prognostic value. METHODS AND RESULTS: ECGs from 46,933 patients were analyzed using computerized measurements and algorithms. The Simplified Selvester Score, the Cardiac Infarction Injury Score (CIIS), and a Q-wave score were calculated. Other ECG characteristics such as left ventricular hypertrophy and bundle-branch blocks were also evaluated. The main outcome was cardiovascular (CV) mortality. During a mean follow-up of 6 years, the CIIS outperformed all other ECG classifications in determining prognosis. Going from lowest to highest tertile of CIIS, each step had a hazard ratio of 1.39 (CI 1.32-1.45) or a 39% increase in risk per tertile. Using clinically based thresholds, the annual mortality for high-risk CIIS was 4.5% (CI 4.0-4.6) versus 0.3% (CI 0.0-1.3) for those in the low-risk group. CONCLUSIONS: A low-risk damage score was associated with a <1% annual CV mortality and a high-risk damage score with annual CV mortality of >4%. A damage score should be calculated as part of all computerized ECG interpretations.

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PubMed2005

Prognostic value of electrocardiographic criteria for left ventricular hypertrophy.

BACKGROUND: Many electrocardiographic (ECG) criteria for left ventricular hypertrophy (LVH) exist, but few studies have compared their relative prognostic value for predicting cardiovascular (CV) mortality. METHODS: We analyzed the first ECG on 46950 consecutive veterans. We targeted male outpatients with a body mass index > 20 to avoid confounding by complicating catabolic illnesses and further excluded those with conduction abnormalities. Using Cox regression models adjusted for age, heart rate, and body mass index, we compared the hazard ratios (HRs) for CV mortality obtained from seventeen commonly used ECG criteria for LVH. RESULTS: During a mean follow-up of 7 +/- 4 years, in a total population of 19434 patients (mean age 54 +/- 14 years), 1254 (6%) patients died of CV causes. The adjusted HR for CV mortality ranged from 1.4 (95% CI 1.2-1.6) to 3.7 (95% CI 2.7-5.0) among the various criteria. Left ventricular hypertrophy defined by composite criteria was generally associated with higher adjusted HRs compared with voltage-only criteria. Among patients with ECG-LVH, the presence of a left ventricular strain pattern or increased negative P-terminal force were most predictive of CV mortality (HR 3.9 and 3.5, 95% CI 3.3-4.6 and 2.8-4.2). CONCLUSIONS: Compared with voltage-only criteria for detecting LVH, composite ECG criteria are more strongly predictive of CV mortality. By applying these ECG criteria into routine clinical practice, individuals with LVH who are at higher risk for CV mortality can be identified and appropriately treated.

Electrocardiography↗
PubMed2005

The importance of heart rate recovery in patients with heart failure or left ventricular systolic dysfunction.

BACKGROUND: The ability to better predict outcome with exercise testing in patients with heart failure (HF) and left ventricular systolic dysfunction (LVSD) may prove extremely valuable in determining which patients are at increased risk. This study evaluated the ability of heart rate recovery (HRR) to predict outcome in patients with HF and validate previous findings in LVSD. METHODS AND RESULTS: HRR was measured at 1-, 2-, 3-, and 5-minute time points after treadmill testing in 2,193 males being evaluated for chest pain at the Palo Alto and Long Beach VA Hospitals. Left ventricular ejection fraction (LVEF) was calculated using biplane ventriculography and patients were considered to have LVSD if they had an LVEF <50%. Angiographic and clinical data was available for all patients. Of the 2,193 patients, 314 patients had LVSD and 109 had a history of HF. Both HF patients and patients with LVSD with a normal HRR at 2 minutes had improved survival compared with patients that had an abnormal HRR at 2 minutes when adjusted for age and beta-blocker use (HF adjusted odds ratio 0.25, 95% CI 0.10-0.66, P < .006; LVSD alone adjusted odds ratio 0.25, 95% CI 0.13-0.47, P < .0001). Stepwise proportional hazard regression analysis revealed that only 2-minute HRR, age, LVEF, and chronic obstructive pulmonary disorder were significant predictors of mortality in patients with LVSD and only HRR at 2 minutes and LV hypertrophy were significant predictors of mortality in patients with HF. CONCLUSION: HRR is a significant predictor of mortality in patients with HF and patients with LVSD and may be useful in better determining prognosis.

Adrenergic beta-Antagonists↗
PubMed2005

Spatial QRS-T angle predicts cardiac death in a clinical population.

OBJECTIVES/BACKGROUND: The purpose of this study was to validate the prognostic value of computer-derived measurements of the spatial alignment of ventricular depolarization and repolarization from the standard 12-lead ECG in a general medical population. METHODS: Analyses were performed on the first ECG digitally recorded from 46,573 consecutive patients since 1987. QRS and T vector were synthesized by deriving XYZ leads from the 12 leads using the inverse Dower weighting matrix. Subset analyses were considered in patients with and those without standard ECG diagnoses (i.e., atrial fibrillation, Q waves, left ventricular hypertrophy, prolonged QRS duration). The main outcome measure was cardiovascular mortality. RESULTS: During a mean follow-up of 6 years, 4,127 cardiovascular deaths occurred. After adjusting for age, heart rate, and gender in a Cox regression analysis, spatial QRS-T angle was the most significant predictor of cardiovascular mortality, outperforming all other ECG measurements and diagnostic statements. In the subset with ECGs free of any standard diagnoses, annual cardiovascular mortality was 0.8% for normal (0-50 degrees ), 2.3% for borderline (50-100 degrees ), and 5.1% for abnormal (100-180 degrees ) QRS-T angle groups. The borderline and abnormal angle groups had 1.5- and 1.9-fold higher risk, respectively, relative to the normal QRS-T angle group after adjustment for age, gender, and heart rate. Similar results were found when patients with standard ECG diagnosis were included or compared. CONCLUSIONS: Spatial QRS-T angle is a significant and independent predictor of cardiovascular mortality that provides greater prognostic discrimination than any of the commonly utilized ECG diagnostic classifications.

Cardiovascular Diseases↗
PubMed2005

C-reactive protein, metabolic syndrome, and insulin resistance in individuals with spinal cord injury.

BACKGROUND/OBJECTIVE: High-sensitivity C-reactive protein (hsCRP) has been shown to be indicative of elevated risk of cardiovascular disease (CVD). We examined this blood marker in persons with spinal cord injury (SCI) in order to determine its potential for predicting elevated cardiac risk. METHODS: In a cross-sectional analysis, we examined the relationship between hsCRP and insulin resistance and metabolic syndrome among 93 individuals with SCI (50.2 +/- 13 years). Fasting lipids, insulin, glucose, plasma hsCRP, and anthropometric data were gathered from each subject. Comparisons were made with population reference values. RESULTS: Metabolic syndrome and insulin resistance were present in nearly one quarter of the SCI population (22.6%). Subjects with fasting insulin resistance had significantly higher mean hsCRP (4.29 +/- 3.25 mg/L) than those who were not insulin resistant (2.24 +/- 2.02) (P < 0.05). Moreover, hsCRP was significantly elevated in individuals who presented with high cardiovascular risk including severe dyslipidemia (> or = 4 abnormal lipid values) and Framingham Risk scores < or = 6 (P < 0.05 for both values). In addition, the homeostasis model assessment of insulin resistance was mildly correlated with hsCRP (r = 0.33). CONCLUSIONS: In individuals with SCI who are insulin resistant and/or display components of the metabolic syndrome, hsCRP is elevated suggesting a clinically important association with cardiovascular risk in this population.

Adult↗
PubMed2004

Treadmill scores in elderly men.

OBJECTIVES: This study seeks to further characterize the role of exercise testing in the elderly for prognosis and diagnosis of coronary artery disease. BACKGROUND: Recent exercise testing guidelines have recognized that statements regarding the elderly do not have an adequate evidence-based quality because the studies they are based on have limitations in sample size and design. The Duke Treadmill Score has been recommended for risk stratification, but recent evidence has suggested that it does not function in the elderly. METHODS: The study population consisted of male veterans (1872 patients >or=65 years; 3798 patients <65 years) who underwent routine clinical exercise testing with a mean follow-up of six years. A subset who underwent coronary angiography as clinically indicated (elderly, n = 405; younger, n= 809) were included. The primary outcome for all subjects was cardiovascular mortality with coronary angiographic findings as the outcome in those selected for angiography. RESULTS: In survival analysis, exercise-induced ST depression was prognostic in both age groups only when cardiovascular death was considered as the end point. Peak metabolic equivalents were the most significant predictor for both age groups only when all-cause death was considered as the end point. New age-specific prognostic scores were developed and found to be predictive for cardiovascular mortality in the elderly. Moreover, in the angiographic subset of the elderly, a specific diagnostic score provided significantly better discrimination than exercise ST measurements alone. For any new score, there is a need for validation in another elderly population. CONCLUSIONS: The mortality end point affected the choice of prognostic variables. This study demonstrates that exercise test scores can be helpful for the diagnosis and prognosis of coronary disease in the elderly.

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PubMed2004

Importance of the first two minutes of heart rate recovery after exercise treadmill testing in predicting mortality and the presence of coronary artery disease in men.

We retrospectively analyzed exercise treadmill and coronary angiographic data of 2,193 men to compare heart rate (HR) recovery with angiographic and mortality data during a follow-up study of 7 +/- 2.7 years. Only the first 2 minutes of HR recovery predicted mortality (p <0.001), and the HR decrease during the second minute of recovery predicted the presence of coronary artery disease (p <0.05).

Coronary Disease↗
PubMed2004

Electrocardiographic arrhythmia risk testing.

Among the most compelling challenges facing cardiologists today is identification of which patients are at highest risk for sudden death. Automatic implantable cardioverter-defibrillators are now indicated in many of these patients, yet the role of noninvasive risk stratification in classifying patients at high risk is not well defined. The purpose of this review is to evaluate the various electrocardiographic (ECG) techniques that appear to have potential in assessment of risk for arrhythmia. The resting ECG (premature ventricular contractions, QRS duration, damage scores, QT dispersion, and ST segment and T wave abnormalities), T wave alternans, late potentials identified on signal-averaged ECGs, and heart rate variability are explored. Unequivocal evidence to support the widespread use of any single noninvasive technique is lacking; further research in this area is needed. It is likely that a combination of risk evaluation techniques will have the greatest predictive power in enabling identification of patients most likely to benefit from device therapy.

Arrhythmias, Cardiac↗
PubMed2004

The current and future role of percutaneous coronary intervention in patients with coronary artery disease.

With increasing research on vulnerable plaques and uncertainty regarding which lesions require revascularization, the goal of this review is to clarify the indications for percutaneous coronary intervention and discuss which lesions do not warrant treatment by intervention. This paper also briefly reviews the potential advantages and limitations of technology that may enable detection of atherosclerotic plaques that are prone to rupture and discusses the future utility of these technologies in prevention of acute coronary syndromes. Providing an evidence-based understanding of lesion morphology and clinical variables that influence outcome enables the interventional cardiologist to determine which atherosclerotic plaques require PCI.

Angina Pectoris↗
PubMed2004

Effect of age and end point on the prognostic value of the exercise test.

BACKGROUND: The clinical and exercise test variables chosen for predicting prognosis vary in the available studies. This could be due to the effect of age of the patients tested and the choice of outcomes used as end points in these follow-up studies. OBJECTIVE: To evaluate the effect of age and end points on exercise test variables chosen as significantly and independently associated with time to death. METHODS: Analyses were performed on the first treadmill test performed on consecutive male veterans at the Palo Alto and Long Beach Veterans Affairs Medical Centers since 1987. After removal of patients with congestive heart failure, coronary interventions, left bundle-branch block, atrial fibrillation, myocardial infarction and/or Q wave, and digoxin use, 3,745 male subjects remained. The outcomes were cardiovascular and all-cause mortality. The study population was divided into subsets according to age; exercise test and clinical variables were analyzed within the age subsets using the Cox hazard model. RESULTS: The mean age at the time of testing was 57 +/- 12 years (+/- SD) and they were followed up for a mean of 6.6 years. There were 544 all-cause deaths, with 206 of the deaths being due to cardiovascular causes (38%). When the study group was classified into subsets based on age, exercise capacity (in metabolic equivalents [METs]) was chosen by the Cox hazard model most consistently in the age groups using either end point. Even when age was added to the Duke treadmill score, prediction of death did not improve in those > 70 years of age because of the nonlinear relationship between age, the exercise test variables, and time to death. The most important age cut points for clinically important differences in exercise test predictors appeared to be 70 years and 75 years of age. In the patients 70 to 75 years of age, peak METs was the only variable predictive of all-cause mortality, and exercise-induced ST-segment depression was the only predictor of cardiovascular death; in the patients > 75 years of age, none of the exercise test responses were predictive of either death outcome. CONCLUSION: Both age and the outcome selected as an end point affect the exercise test responses chosen for scores to predict prognosis. Differences in age of the subjects tested and/or the outcome selected as the end point can explain the differences in the studies using exercise testing to predict prognosis.

Adult↗
PubMed2004

Health-care costs and exercise capacity.

BACKGROUND: While the beneficial effect of exercise capacity on mortality is well-accepted, its effect on health-care costs remains uncertain. This study investigates the relationship between exercise capacity and health-care costs. METHODS: The Veterans Affairs Health Care System recently implemented a Decision Support System that provides data on patterns of care, patient outcomes, workload, and costs. Total inpatient and outpatient costs were derived from existing administrative and clinical data systems, were adjusted for relative value units, and were expressed in relative cost units. We used univariable and multivariable analyses to evaluate the 1-year total costs in the year following a standard exercise test. Costs were compared with exercise capacity estimated in metabolic equivalents (METs), other test results, and clinical variables for 881 consecutive patients who were referred for clinical reasons for treadmill testing at the Palo Alto Veterans Affairs Health Care System facility between October 1, 1998, and September 30, 2000. RESULTS: The patients had a mean age of 59 years, 95% were men, and 74% were white. Eight patients (< 1%) died during the year of follow-up. Exercise testing showed an average maximum heart rate of 138 beats/min, 8.2 METs, and a peak Borg scale of 17. In unadjusted analysis, costs were incrementally lower by an average of 5.4% per MET increase (p < 0.001). In a multivariable analysis adjusting for demographic variables, treadmill test performance and results, and clinical history, METs were found to be the most significant predictor of cost (F-statistic, 21.8; p < 0.001). CONCLUSION: These findings are consistent with the hypothesis that exercise capacity is inversely associated with health-care costs.

Data Collection↗
PubMed2003

The effect of ethnicity on survival in male veterans referred for electrocardiography and treadmill testing.

BACKGROUND: Ethnic differences in the relationship between access to health care and survival are difficult to define because of many confounding factors, such as socioeconomic status and baseline differences in health. Because the Veterans Affairs health care system offers health care largely without financial considerations, it provides an ideal setting in which to identify and understand ethnic differences in health outcomes. Previous studies in this area have lacked clinical and cardiovascular data with which to adjust for baseline differences in patients' health. METHODS: Data were collected from consecutive men referred for resting electrocardiography (ECG) (n = 41 087) or exercise testing (n = 6213) during 12 years. We compared ethnic differences in survival between whites, blacks, and Hispanics after considering baseline differences in age and hospitalization status. We also adjusted for electrocardiogram abnormalities and cardiac risk factors, exercise test results, and cardiovascular comorbidities. RESULTS: White patients tended to be older and had more baseline comorbidities and cardiovascular interventions when they presented for testing. White patients had increased mortality rates compared with blacks and Hispanics. In the ECG population, after adjusting for demographics and baseline electrocardiogram abnormalities, Hispanics had improved survival compared with whites and blacks. In the exercise test population, after adjusting for the same factors, as well as adjusting for the presence of cardiovascular comorbidities, cardiac risk factors, and exercise test findings, Hispanics also exhibited improved survival compared with the other 2 ethnicities. There were no differences in mortality rates between whites and blacks. CONCLUSION: Our findings demonstrate that the health care provided to veterans referred for routine ECG or exercise testing is not associated with poorer survival in ethnic minorities.

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