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Biomedical subjects

T E Cuddy

Publications and source records attributed to T E Cuddy.

At least 19 recordsLinked to original sources
PubMed1995

Tracking of blood pressure over a 40-year period in the University of Manitoba Follow-up Study, 1948-1988.

High blood pressure is a well-recognized, modifiable, cardiovascular disease risk factor. Tracking of blood pressure was examined in the University of Manitoba Follow-up Study, a cohort of 3,983 men followed over a 40-year period, between 1948 and 1988. Blood pressure measurements recorded over time in these men, prior to the development of ischemic heart disease, were used in this analysis. Two approaches to tracking were used; correlation analysis and the quantification of the likelihood for a man whose blood pressure was in either the top or bottom quintile to remain in the extreme end of the distribution at later measurement. For ages 25-75 years and for intervals between blood pressure measurement ranging from 5 to 35 years, significant evidence for tracking was found. The strongest evidence for tracking was in middle age, 45-55 years. Strength of tracking decreased with increasing time between measurements. This analysis suggests that men at highest risk for hypertension can be identified at a young age. Hence, strategies for prevention of cardiovascular complications can be targeted in early adulthood.

Adult↗
PubMed1995

The natural history of atrial fibrillation: incidence, risk factors, and prognosis in the Manitoba Follow-Up Study.

PURPOSE: Atrial fibrillation is a common arrhythmia associated with increased cardiovascular morbidity and mortality. This study was undertaken to identify the natural history of this condition, including risk factors for its development, and outcome. PATIENTS AND METHODS: The incidence of atrial fibrillation among 3,983 male air crew recruits observed continuously for 44 years was calculated based on person-years of observation. Age and 23 variables were examined to identify risk factors for atrial fibrillation. Controlling for age and 9 prognostic variables, the effect of atrial fibrillation on 8 outcomes was examined. Analysis of risk factors for atrial fibrillation and outcome after atrial fibrillation was based on a Cox proportional hazard model using time-dependent covariates. RESULTS: Of the 3,983 study members, 299 (7.5%) developed atrial fibrillation during 154,131 person-years of observation. The incidence rose with age from less than 0.5 per 1,000 person-years before age 50 to 9.7 per 1,000 person-years after age 70. Risk for atrial fibrillation was increased with myocardial infarction (relative risk [RR] 3.62), angina (RR 2.84), and ST-T wave abnormalities in the absence of ischemic heart disease (RR 2.21). The RR for atrial fibrillation was strongest at the onset of ischemic heart disease and diminished over time. The rate of atrial fibrillation was 1.42 times increased in men with a history of hypertension. Congestive heart failure, valvular heart disease, and cardiomyopathy were important but uncommon risk factors. Atrial fibrillation independently increased the risk for stroke (RR 2.07) and congestive heart failure (RR 2.98). Total mortality rate was increased 1.31 times; cardiovascular mortality including and excluding fatal stroke were also increased (RR 1.41 and 1.37, respectively). CONCLUSIONS: The incidence of atrial fibrillation in men increases with advancing age. Clinical cardiac abnormalities, particularly recent ischemic heart disease and hypertension, are strongly associated with increased risk for atrial fibrillation. Atrial fibrillation increases morbidity and mortality, but the magnitude of the increase may be less than previously reported.

Adult↗
PubMed1993

A comparison of management patterns after acute myocardial infarction in Canada and the United States. The SAVE investigators.

BACKGROUND: There are major differences in the organization of the health care systems in Canada and the United States. We hypothesized that these differences may be accompanied by differences in patient care. METHODS: To test our hypothesis, we compared the treatment patterns for patients with acute myocardial infarction in 19 Canadian and 93 United States hospitals participating in the Survival and Ventricular Enlargement (SAVE) study, which tested the effectiveness of captopril in this population of patients after a myocardial infarction. RESULTS: In Canada, 51 percent of the patients admitted to a participating coronary care unit had acute myocardial infarctions, as compared with only 35 percent in the United States (P < 0.001). Despite the similar clinical characteristics of the 1573 U.S. patients and 658 Canadian patients participating in the study, coronary arteriography was more commonly performed in the United States than in Canada (in 68 percent vs. 35 percent, P < 0.001), as were revascularization procedures before randomization (31 percent vs. 12 percent, P < 0.001). During an average follow-up of 42 months, these procedures were also performed more commonly in the United States than in Canada. These differences were not associated with any apparent difference in mortality (22 percent in Canada and 23 percent in the United States) or rate of reinfarction (14 percent in Canada and 13 percent in the United States), but there was a higher incidence of activity-limiting angina in Canada than in the United States (33 percent vs. 27 percent, P < 0.007). CONCLUSIONS: The threshold for the admission of patients to a coronary care unit or for the use of invasive diagnostic and therapeutic interventions in the early and late periods after an infarction is higher in Canada than in the United States. This is not associated with any apparent difference in the rate of reinfarction or survival, but is associated with a higher frequency of activity-limiting angina.

Angina Pectoris↗
PubMed1992

Effect of captopril on mortality and morbidity in patients with left ventricular dysfunction after myocardial infarction. Results of the survival and ventricular enlargement trial. The SAVE Investigators.

BACKGROUND: Left ventricular dilatation and dysfunction after myocardial infarction are major predictors of death. In experimental and clinical studies, longterm therapy with the angiotensin-converting--enzyme inhibitor captopril attenuated ventricular dilatation and remodeling. We investigated whether captopril could reduce morbidity and mortality in patients with left ventricular dysfunction after a myocardial infarction. METHODS: Within 3 to 16 days after myocardial infarction, 2231 patients with ejection fractions of 40 percent or less but without overt heart failure or symptoms of myocardial ischemia were randomly assigned to receive doubleblind treatment with either placebo (1116 patients) or captopril (1115 patients) and were followed for an average of 42 months. RESULTS: Mortality from all causes was significantly reduced in the captopril group (228 deaths, or 20 percent) as compared with the placebo group (275 deaths, or 25 percent); the reduction in risk was 19 percent (95 percent confidence interval, 3 to 32 percent; P = 0.019). In addition, the incidence of both fatal and nonfatal major cardiovascular events was consistently reduced in the captopril group. The reduction in risk was 21 percent (95 percent confidence interval, 5 to 35 percent; P = 0.014) for death from cardiovascular causes, 37 percent (95 percent confidence interval, 20 to 50 percent; P less than 0.001) for the development of severe heart failure, 22 percent (95 percent confidence interval, 4 to 37 percent; P = 0.019) for congestive heart failure requiring hospitalization, and 25 percent (95 percent confidence interval, 5 to 40 percent; P = 0.015) for recurrent myocardial infarction. CONCLUSIONS: In patients with asymptomatic left ventricular dysfunction after myocardial infarction, long-term administration of captopril was associated with an improvement in survival and reduced morbidity and mortality due to major cardiovascular events. These benefits were observed in patients who received thrombolytic therapy, aspirin, or beta-blockers, as well as those who did not, suggesting that treatment with captopril leads to additional improvement in outcome among selected survivors of myocardial infarction.

Adult↗
PubMed1992

The natural history of electrocardiographic preexcitation in men. The Manitoba Follow-up Study.

OBJECTIVE: To examine the natural history of preexcitation occurring on the routine electrocardiogram (ECG). DESIGN: A longitudinal cohort study of 3983 originally healthy men followed prospectively for 40 years. SETTING: Free-living (community-dwelling) study members residing predominantly in Canada. PARTICIPANTS: Nineteen male study members with preexcitation occurring during routine examination in the 40-year follow-up of the Manitoba Follow-up Study. MEASUREMENTS: Routinely requested clinical examinations and ECGs, supplemented by information supplied by the study member or his physician. MAIN RESULTS: Ten study members were found to have preexcitation at enrollment, for a prevalence of 2.5 per 1000 (95% CI, 1.2 to 4.6). A delta wave was first detected during follow-up in an additional nine study members. Seventeen of 19 study members did not have the delta wave at some later time, and preexcitation was intermittently present in most of these members. Over time there was a loss of preexcitation, with 15 of 19 study members no longer exhibiting a delta wave by the end of follow-up. Five of 11 study members with symptoms had physician confirmation of an arrhythmia. Fourteen study members remain alive, and none of the five deaths was attributed to preexcitation. CONCLUSIONS: Preexcitation found on routine ECG in our originally healthy male study group did not confer excess morbidity or mortality, even in those study members who developed symptomatic arrhythmias. Most preexcitation was intermittent and disappeared over time.

Adolescent↗
PubMed1992

Oxidative status of lipoproteins in coronary disease patients.

Oxidized low-density lipoprotein (LDL) may play an important role in atherogenesis. The oxidative status of isolated LDL and very low-density lipoprotein (VLDL) were investigated in 23 patients with proven coronary disease and in 23 healthy asymptomatic control subjects. Oxidized cholesterol (4-cholesten-3-one and 20 alpha-OH cholesterol) was identified in LDL and VLDL from both groups. The content of cholesterol and 4-cholesten-3-one in LDL from patients was significantly increased in comparison with values from the control subjects. Lipid peroxidation, as assessed by malondialdehyde (MDA) formation, was barely detectable in native LDL and VLDL from the two groups. However, after incubation with a free radical-producing system, MDA levels in LDL from patients were significantly higher than those in control subjects. Lysine reactivity in LDL after incubation with an oxidizing agent, CuSO4, was similar between groups. However, lysine reactivity to CuSO4 in VLDL from patients was less than that in control subjects. Our results suggest that LDL levels from patients with coronary disease have an elevated oxidized cholesterol content and are more susceptible to peroxidative modification. Conversely, the LDL apoprotein does not appear to have been oxidatively modified in these patients. The data are consistent with a role for oxidized LDL in coronary artery disease and indicate that the LDL lipid may be an important oxidation site.

Cholestenones↗
PubMed1992

The natural history of asymptomatic complete heart block. A case series from the Manitoba Follow-up Study.

Long-standing asymptomatic complete heart block is unusual in adults. The natural history of this condition with advancing age is unknown. Four cases of complete heart block documented in patients for 23 to 48 years are reported. These men had no evidence of structural heart disease and functioned normally without symptoms for many years. Three of the four subsequently developed symptoms and required permanent pacemaker insertion. These cases illustrate the good prognosis of asymptomatic complete heart block, but raise the concern that with advancing age, intervention with pacing frequently is necessary.

Adult↗
PubMed1992

Regular narrow QRS complex tachycardias in the Manitoba Follow-up Study (1948-88).

OBJECTIVE: To determine the incidence, risk factors and prognosis of regular narrow QRS complex tachycardia (NQT), which develops in the absence of pre-excitation in subjects free from ischemic heart disease in the Manitoba Follow-up Study. DESIGN AND SETTING: The Manitoba Follow-up Study is a longitudinal cardiovascular study of 3983 initially healthy men (primarily living in Canada) followed prospectively for 40 years. Risk factors and prognosis were assessed in a nested case-control study. MAIN RESULTS: Twenty-two individuals were diagnosed with NQT before clinical and/or electrocardiographic manifestation of ischemic heart disease (145,408 person-years of observation). Between the ages of 30 and 80, the incidence of NQT was one per 6000 person-years and increased with age. History of childhood diseases, valvular disease, smoking, elevated blood pressure and body mass index did not increase the likelihood for NQT development. NQT was diagnosed concurrently with a serious noncardiac condition in seven cases; excess mortality resulted as six of these subjects died within one year of NQT diagnosis while only two subjects without concurrent disease at NQT diagnosis died during follow-up. In comparison with 2% of control subjects, 27% of subjects with NQT subsequently developed electrocardiographical evidence of atrial fibrillation (relative risk was 12 with lower 95% confidence limit of 1.8). CONCLUSIONS: NQT in an otherwise healthy individual is a benign condition and increases the likelihood of atrial fibrillation development.

Adult↗
PubMed1975

Dose-response relation between therapeutic levels of serum digoxin and systolic time intervals.

A dose-response relation between cardiac glycosides and systolic time intervals has previously been established in short-term studies in which the glycoside was administered intravenously in these studies there was uncertainty regarding the steady state kinetics, and maintenance of the early serum levels would have resulted in toxicity. Accordingly, we studied the effect on systolic time intervals of small increments of serum digoxin within the therapeutic range. Serum digoxin concentration and systolic time intervals were measured in 21 patients receiving 0.25 mg of the glycoside daily. The daily dose was increased to 0.5 mg and measurements were repeated 5 to 7 days later. Serum digoxin concentration with the smaller dose was 0.56 plus or minus (standard error) 0.06 ng/ml and increased to 1.18 plus or minus 0.11 ng/ml with the larger dose. Associated with the increased serum digoxin was a mean decrease in duration of total electromechanical events of 6.3 plus or minus 2.9 msec (P smaller than 0.025), which resulted from a mean shortening of left ventricular ejection time of 5.6 plus or minus 3.0 msec (P smaller than 0.05). The mean decrease in preejection phase of 1.1 plus or minus 2.1 msec was insignificant (P larger than 0.2). Repeated measurements in control patients showed no change in serum digoxin concentration or systolic time intervals. In nine patients the digoxin dose was randomly varied between 0 and 0.75 mg and measurements were made 4 to 5 days after drug administration at each dose level. The correlation coefficient between changes in serum digoxin and changes in left ventricular ejection time was minus 0.55 (P smaller than 0.01) the data indicated that increasing the maintenance dose of digoxin while keeping the serum level within therapeutic range will result in improved ventricular function as assessed by determination of systolic time intervals.

Adult↗