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Biomedical subjects

S Yusuf

Publications and source records attributed to S Yusuf.

At least 55 records · Page 3Linked to original sources
PubMed2001

Relationship between pacemaker dependency and the effect of pacing mode on cardiovascular outcomes.

BACKGROUND: A recently completed trial, the Canadian Trial of Physiological Pacing (CTOPP), showed that physiological pacing did not significantly reduce mortality, stroke, or heart failure hospitalization, but it did show that atrial fibrillation occurred less frequently in patients with physiological pacing. Many pacemaker patients experience only transient bradyarrhythmias with an adequate unpaced heart rate (UHR) and are not pacemaker-dependent. The purpose of the present analysis was to determine if pacemaker-dependent patients have an increased benefit from physiological pacing compared with non-pacemaker-dependent patients. METHODS AND RESULTS: Of 2568 patients included in the CTOPP trial, 2244 patients had a pacemaker dependency test performed at the first follow-up visit. The yearly event rate of cardiovascular death or stroke steadily increased with decreasing UHR in the ventricular pacing group, but it remained constant in the physiological pacing group. When the patients were subdivided to UHR </=60 bpm or >60 bpm, there was an interaction between pacing mode treatment and UHR subgroup. The Kaplan-Meier plot confirmed a physiological pacing advantage only in the UHR </=60 bpm subgroup. This differential effect was also present for the outcomes of cardiovascular death and total mortality. CONCLUSIONS: This study demonstrated that UHR at first follow-up has an important influence on how pacing mode selection affects cardiovascular death and total mortality. Pacemaker-dependent patients with low UHR will probably be paced frequently and will likely benefit from physiological pacing. In contrast, non-pacemaker-dependent patients will likely be paced infrequently and may not benefit from physiological pacing.

Aged↗
PubMed2001

Renal insufficiency as a predictor of cardiovascular outcomes and the impact of ramipril: the HOPE randomized trial.

BACKGROUND: The cardiovascular risk associated with early renal insufficiency is unknown. Clinicians are often reluctant to use angiotensin-converting enzyme inhibitors in patients with renal insufficiency. OBJECTIVE: To determine whether mild renal insufficiency increases cardiovascular risk and whether ramipril decreases that risk. DESIGN: Post hoc analysis. SETTING: The Heart Outcomes and Prevention Evaluation (HOPE) study, a randomized, double-blind, multinational trial involving 267 study centers. PATIENTS: 980 patients with mild renal insufficiency (serum creatinine concentration >/= 124 micromol/L [>/=1.4 mg/dL]) and 8307 patients with normal renal function (serum creatinine concentration < 124 micromol/L [<1.4 mg/dL]) Patients with a baseline serum creatinine concentration greater than 200 micromol/L (2.3 mg/dL) were excluded. MEASUREMENTS: The primary outcome measure was incidence of cardiovascular death, myocardial infarction, or stroke. RESULTS: Cumulative incidence of the primary outcome was higher in patients with renal insufficiency than in those without (22.2% vs. 15.1%; P < 0.001) and increased with serum creatinine concentration. Patients with renal insufficiency had a substantially increased risk for cardiovascular death (11.4% vs. 6.6%) and total mortality (17.8% vs. 10.6%) (P < 0.001 for both comparisons). The effect of renal insufficiency on the primary outcome (adjusted hazard ratio, 1.40 [95% CI, 1.16 to 1.69]) was independent of known cardiovascular risks and treatment. Ramipril reduced the incidence of the primary outcome in patients with and those without renal insufficiency (hazard ratio, 0.80 vs. 0.79; P > 0.2 for the difference). CONCLUSIONS: In patients who had preexisting vascular disease or diabetes combined with an additional cardiovascular risk factor, mild renal insufficiency significantly increased the risk for subsequent cardiovascular events. Ramipril reduced cardiovascular risk without increasing adverse effects.

Aged↗
PubMed2001

Effects of ramipril and vitamin E on atherosclerosis: the study to evaluate carotid ultrasound changes in patients treated with ramipril and vitamin E (SECURE).

BACKGROUND: Activation of the renin-angiotensin-aldosterone system and oxidative modification of LDL cholesterol play important roles in atherosclerosis. The Study to Evaluate Carotid Ultrasound changes in patients treated with Ramipril and vitamin E (SECURE), a substudy of the Heart Outcomes Prevention Evaluation (HOPE) trial, was a prospective, double-blind, 3x2 factorial design trial that evaluated the effects of long-term treatment with the angiotensin-converting enzyme inhibitor ramipril and vitamin E on atherosclerosis progression in high-risk patients. METHODS AND RESULTS: A total of 732 patients >/=55 years of age who had vascular disease or diabetes and at least one other risk factor and who did not have heart failure or a low left ventricular ejection fraction were randomly assigned to receive ramipril 2.5 mg/d or 10 mg/d and vitamin E (RRR-alpha-tocopheryl acetate) 400 IU/d or their matching placebos. Average follow-up was 4.5 years. Atherosclerosis progression was evaluated by B-mode carotid ultrasound. The progression slope of the mean maximum carotid intimal medial thickness was 0.0217 mm/year in the placebo group, 0.0180 mm/year in the ramipril 2.5 mg/d group, and 0.0137 mm/year in the ramipril 10 mg/d group (P=0.033). There were no differences in atherosclerosis progression rates between patients on vitamin E and those on placebo. CONCLUSIONS: Long-term treatment with ramipril had a beneficial effect on atherosclerosis progression. Vitamin E had a neutral effect on atherosclerosis progression.

Aged↗
PubMed2001

Prognostic significance of thrombocytopenia during hirudin and heparin therapy in acute coronary syndrome without ST elevation: Organization to Assess Strategies for Ischemic Syndromes (OASIS-2)study.

BACKGROUND: The development of thrombocytopenia in acute coronary syndromes (ACS) appears to be associated with adverse clinical outcomes. Unfractionated heparin is a recognized cause of thrombocytopenia, but the incidence, predictors, and prognostic significance of thrombocytopenia during hirudin therapy in ACS have not been reported. METHODS AND RESULTS: Patients with ACS without ST elevation were randomized in a double-blind manner to receive a 72-hour intravenous infusion of unfractionated heparin or hirudin. Platelet counts were measured at baseline and within 24 hours of completion of study drug. The overall incidence of thrombocytopenia (<100x10(9)/L) was 1% and was similar in unfractionated heparin- and hirudin-treated patients (P:=0.42). Thrombocytopenia during study drug infusion was an independent predictor of 7-day outcomes, including death (OR, 6.7; 95% CI, 1.9 to 25); the composite of death, myocardial infarction, and recurrent ischemia (OR, 2.0; 95% CI, 1.0 to 1.5); revascularization (OR, 4.0; 95% CI, 2.2 to 7.1); and major bleeding (OR, 8.3; 95% CI, 3.4 to 17.7). Among patients who developed thrombocytopenia, hirudin (OR, 5.4; 95% CI, 2.6 to 11.3) but not unfractionated heparin (OR, 2.0; 95% CI, 0.3 to 14.4) therapy was associated with a significantly increased risk of major bleeding. CONCLUSIONS: Early-onset thrombocytopenia in patients with ACS without ST elevation is strongly associated with adverse clinical outcomes, including death, ischemic events, and bleeding. The excess of major bleeding in hirudin-treated patients who develop thrombocytopenia suggests that thrombocytopenia may contribute to the increased risk of bleeding observed with hirudin.

Acute Disease↗
PubMed2001

Impact of right ventricular involvement on mortality and morbidity in patients with inferior myocardial infarction.

OBJECTIVES: We sought to evaluate the prognostic impact of right ventricular (RV) myocardial involvement in patients with inferior myocardial infarction (MI). BACKGROUND: There is uncertainty regarding the risk of major complications in patients with inferior MI complicated by RV myocardial involvement. Whether these complications are related to RV myocardial involvement itself or simply to the extent of infarction involving the left ventricle (LV) is also unknown. METHODS: We examined the incidence of death and mechanical and electrical complications in patients with (n = 491) and without (n = 638) RV myocardial involvement and in patients with anterior MI (n = 971) in an analysis from the Collaborative Organization for RheothRx Evaluation (CORE) trial. Left ventricular infarct size was assessed by technetium-99m-sestamibi single-photon emission computed tomography and peak creatine kinase, and LV function was assessed by radionuclide angiography. We also performed a meta-analysis in which we pooled the results of our study with previous smaller studies addressing the same question. RESULTS: Six-month mortality was 7.8% in inferior MI compared with 13.2% in anterior MI. Among patients with inferior MI, serious arrhythmias were significantly more common in patients with RV myocardial involvement who also had a trend toward higher mortality, pump failure and mechanical complications. However, this was not associated with a difference in LV infarct size or function. A meta-analysis of six studies (n = 1,198) confirmed that RV myocardial involvement was associated with an increased risk of death (odds ratio [OR] 3.2, 95% confidence interval [CI] 2.4 to 4.1), shock (OR 3.2, 95% CI 2.4 to 3.5), ventricular tachycardia or fibrillation (OR 2.7, 95% CI 2.1 to 3.5) and atrioventricular block (OR 3.4, 95% CI 2.7 to 4.2). CONCLUSIONS: Patients with inferior MI who also have RV myocardial involvement are at increased risk of death, shock and arrhythmias. This increased risk is related to the presence of RV myocardial involvement itself rather than the extent of LV myocardial damage.

Arrhythmias, Cardiac↗
PubMed2001

Relationship of current and past smoking to mortality and morbidity in patients with left ventricular dysfunction.

OBJECTIVES: The aim of this study was to evaluate the impact of smoking in patients with left ventricular dysfunction. BACKGROUND: The impact of smoking in patients with left ventricular dysfunction has not been well-studied. METHODS: We compared the incidence of death, hospitalization due to heart failure and myocardial infarction (MI) in current smokers to ex-smokers of < or =2 years and ex-smokers of >2 years duration to never-smokers among participants of the Study Of Left Ventricular Dysfunction (SOLVD) Prevention and Intervention trials. Participants all had left ventricular ejection fraction (LVEF) <35% and follow-up was over a mean of 41 months. RESULTS: Complete smoking status and outcome data were available in 6,704 subjects. There were 1,562 current smokers, 1,317 ex-smokers of < or =2 years, 2,354 ex-smokers of >2 years and 1,471 never-smokers. After adjusting for baseline differences of age, LVEF, race and etiology of heart failure, current smoking was associated with a significantly increased all-cause mortality (relative risk [RR]: 1.41, 95% confidence interval [CI]: 1.25 to 1.58, p < 0.001) compared with ex-smokers and never-smokers. The incidence of death or recurrent congestive heart failure requiring hospitalization or MI was significantly greater (RR: 1.39, 95% CI: 1.26 to 1.52, p < 0.001) in current smokers compared with ex-smokers and never-smokers. There were no significant differences in the number of deaths or hospitalizations due to heart failure between ex-smokers and never-smokers. This effect was consistent across both the SOLVD Prevention and Treatment trials. CONCLUSIONS: Current smoking is a powerful independent predictor of morbidity (recurrent heart failure and MI) and mortality in patients with left ventricular dysfunction. Quitting smoking appears to have a substantial and early effect (within two years) on decreasing morbidity and mortality in patients with left ventricular dysfunction, which is at least as large as proven drug treatments recommended in patients with left ventricular dysfunction.

Aged↗
PubMed2001

Effect of age on mortality, hospitalizations and response to digoxin in patients with heart failure: the DIG study.

OBJECTIVES: This study was designed to determine the effect of increasing age on mortality, hospitalizations and digoxin side effects in patients with heart failure (HF), and to determine whether the effect of digoxin on clinical outcomes varies as a function of age. BACKGROUND: The incidence and prevalence of HF increase with advancing age, but there are limited data on the clinical course and response to specific therapeutic interventions in elderly patients with HF. METHODS: The Digitalis Investigation Group (DIG) study was a prospective, randomized clinical trial involving 7,788 patients with HF randomized to digoxin or placebo and followed for an average of 37 months. In the present analysis, patients were stratified into five age categories: <50 years (n = 841), 50 to 59 years (n = 1,545), 60 to 69 years (n = 2,885), 70 to 79 years (n = 2,092) and > or =80 years (n = 425). Interactions between age and the following clinical outcomes were examined: total mortality, all-cause hospitalizations, HF hospitalizations, the composite of HF death or HF hospitalization, hospitalization for suspected digoxin toxicity and withdrawal from therapy because of side effects. RESULTS: Increasing age was an independent risk factor for total mortality, all-cause hospitalization, HF hospitalization, HF death or hospital admission, hospitalization for suspected digoxin toxicity and withdrawal from digoxin therapy (all p < 0.001). However, there were no significant interactions between age and digoxin treatment with respect to any of the major clinical end points. CONCLUSIONS: Increasing age is associated with progressively worse clinical outcomes in patients with HF. However, the beneficial effects of digoxin in reducing all-cause admissions, HF admissions, and HF death or hospitalization are independent of age. Thus, digoxin remains a useful agent for the adjunctive treatment of HF due to impaired left ventricular systolic function in patients of all ages.

Age Factors↗
PubMed2001

INTER-HEART: A global study of risk factors for acute myocardial infarction.

BACKGROUND: Although declines in mortality rates have occurred in most developed countries, increases are being seen in developing countries. Our knowledge of risk factors for acute myocardial infarction (AMI) is largely derived from studies in the former. Applicability of these results to other populations is unknown. The objectives of INTER-HEART are to determine the association between risk factors and AMI within populations defined by ethnicity and/or geographic region and to assess the relative importance of risk factors across these populations. METHODS: INTER-HEART is a study of 14,000 cases of AMI and 16,000 matched control patients from 46 countries, which was conducted with a standardized protocol. Questionnaires were translated into 11 languages; physical measurements were obtained, and 20 mL of blood was drawn and shipped frozen to a central laboratory in Canada. The study will evaluate the importance of conventional and emerging risk factors within each geographic region and whether their impact varies by region. RESULTS: INTER-HEART is sponsored by the World Health Organization and the World Heart Federation and has received funding from several peer-reviewed agencies and many different pharmaceutical companies. A vanguard phase (February 1999 to 2000) enrolled 4000 subjects from 41 countries. Full data collection started in April 2000 and is expected to be completed by October 2002. CONCLUSIONS: Several years of targeted work have allowed the development of the concepts that were tested in the pilot studies. This has ensured the feasibility of INTER-HEART. This study has the potential to have a major impact in developing a worldwide strategy for cardiovascular disease prevention, especially in developing countries and nonwhite populations.

Case-Control Studies↗
PubMed2001

Reliability, validity, and responsiveness of the six-minute walk test in patients with heart failure.

BACKGROUND: Our purpose was to evaluate the reliability, validity, and responsiveness of the 6-minute walk test (6MWT) in patients with heart failure (HF) enrolled in the Randomized Evaluation of Strategies for Left Ventricular Dysfunction (RESOLVD) pilot study. METHODS: A total of 768 patients was enrolled in a multicenter randomized clinical trial evaluating the effect of candesartan, enalapril, and metoprolol on left ventricular ejection fraction (LVEF), 6MWT distance, neurohormones, and quality of life. The 6MWT was performed once at screening and twice at baseline, 18 weeks, and 43 weeks by a standardized method. RESULTS: Test-retest reliability at baseline (intraclass correlation coefficient [ICC] = 0.90), 18 weeks (ICC = 0.88), and 43 weeks (ICC = 0.91) was very good. Baseline 6MWT distance was weakly inversely correlated to the quality-of-life cumulative score (r = -0.26, P =.0001) and moderately inversely correlated to the New York Heart Association functional classification (NYHA-FC) (r = -0.43, P =.001). In the RESOLVD study, the 6MWT was not responsive to change when effect sizes and standardized response means were used. Disease-specific quality of life was responsive to change in patients treated with candesartan and enalapril and NYHA-FC was responsive to change in the candesartan and enalapril combination and for enalapril alone with small effect sizes. The 6MWT, NYHA-FC, and quality of life were not responsive to change during the metoprolol or placebo phase. CONCLUSIONS: The 6MWT is highly reproducible in patients with symptoms of HF. It is somewhat correlated to NYHA-FC and quality of life. Overall, quality of life was most responsive to change, whereas 6MWT and NYHA-FC were comparable but less responsive to change in the RESOLVD study.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2001

Previous exposure to Chlamydia pneumoniae, Helicobacter pylori and other infections in Canadian patients with ischemic heart disease.

OBJECTIVE: Previous exposures to Chlamydia pneumoniae (CP), Helicobacter pylori (HP) or cytomegalovirus (CMV) have been associated with atherosclerotic heart disease. These associations were studied in Canadian patients, and the exposure to five infections measured. DESIGN: Case-control study. SETTING: In the coronary care units (Hamilton General site, Henderson General site, McMaster University Medical Centre site of the Hamilton Health Sciences Corporation and St Joseph's Hospital) and from the regional angiography suite (Hamilton General site), Hamilton, Ontario. PATIENTS AND METHODS: One hundred seven consecutive patients presenting with myocardial infarction or unstable angina (coronary care unit patients), or with previous angina or myocardial infarction (angiography suite patients), were compared with 107 family practice or outpatient clinic control subjects. INTERVENTIONS: Cardiovascular risk factors were measured, as was serology for CP, HP, CMV, adenovirus and hepatitis A virus. Statistical analysis was by logistic regression, adjusted for age and sex. RESULTS: Exposure to CP was more frequent in patients than in control subjects (85.4% versus 70.3%, adjusted odds ratio [OR] 2.3, 95% CI 1.1 to 5.1, P=0.03). Dividing CP immunoglobulin G absorbance into quarters, with the lowest quarter as the reference group, the adjusted ORs were 2.8, 3.0 and 4.3, respectively, for the second, third and fourth quarters (P=0.001 for trend). The seroprevalences of HP (61.7%), CMV (64.0%), adenovirus (75.6%) and hepatitis A virus (59.2%) were high, with no association with disease. CONCLUSIONS: An association was found between heart disease and previous exposure to CP, with a stepwise increase in ORs at higher antibody levels, whereas no association was found with HP, CMV or other infections. A prospective validation of this association is needed.

Adult↗
PubMed2001

Validity of the US Behavioral Risk Factor Surveillance System's health related quality of life survey tool in a group of older Canadians.

Investigators at the Centers for Disease Control and Prevention in the US have developed a brief survey tool to measure health-related quality of life (HRQOL-4). In order to support use of such tools in surveillance, it is important to assess their validity in different groups. Subjects were 926 non-institutionalized men and women (age > or = 65 years) who completed a health exam and questionnaire. Results indicated that physical and mental health and physical activity limitation were each related to self-perceived health. Compared with subjects who reported excellent health, those with poor self-rated health reported a more than 17-fold increase in the number of unhealthy days in the previous 30. While responses to questions addressing psychosocial factors were most consistently associated with the HRQOL item relating to mental health, responses to health and health behaviour questions were more consistently associated with items related to physical health. This study demonstrated that the HRQOL-4 is not only accepted by older adults in a self-administered format, but also stands up to tests of its validity.

Age Factors↗
PubMed2000

Impact of diabetes on long-term prognosis in patients with unstable angina and non-Q-wave myocardial infarction: results of the OASIS (Organization to Assess Strategies for Ischemic Syndromes) Registry.

BACKGROUND: Although unstable coronary artery disease is the most common reason for admission to a coronary care unit, the long-term prognosis of patients with this diagnosis is unknown. This is particularly true for patients with diabetes mellitus, who are known to have a high morbidity and mortality after an acute myocardial infarction. METHODS AND RESULTS: Prospectively collected data from 6 different countries in the Organization to Assess Strategies for Ischemic Syndromes (OASIS) registry were analyzed to determine the 2-year prognosis of diabetic and nondiabetic patients who were hospitalized with unstable angina or non-Q-wave myocardial infarction. Overall, 1718 of 8013 registry patients (21%) had diabetes. Diabetic patients had a higher rate of coronary bypass surgery than nondiabetic patients (23% versus 20%, P:<0.001) but had similar rates of catheterization and angioplasty. Diabetes independently predicted mortality (relative risk [RR], 1.57; 95% CI, 1.38 to 1.81; P:<0.001), as well as cardiovascular death, new myocardial infarction, stroke, and new congestive heart failure. Moreover, compared with their nondiabetic counterparts, women had a significantly higher risk than men (RR, 1.98; 95% CI, 1.60 to 2.44; and RR, 1.28; 95% CI, 1.06 to 1.56, respectively). Interestingly, diabetic patients without prior cardiovascular disease had the same event rates for all outcomes as nondiabetic patients with previous vascular disease. CONCLUSIONS: Hospitalization for unstable angina or non-Q-wave myocardial infarction predicts a high 2-year morbidity and mortality; this is especially evident for patients with diabetes. Diabetic patients with no previous cardiovascular disease have the same long-term morbidity and mortality as nondiabetic patients with established cardiovascular disease after hospitalization for unstable coronary artery disease.

Age Factors↗