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Biomedical subjects

F A Mathewson

Publications and source records attributed to F A Mathewson.

16 recordsLinked to original sources
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↗
PubMed1986

The natural history of primary first-degree atrioventricular heart block.

The long-term prognosis of first-degree heart block in the absence of organic heart disease has not been clearly defined. We addressed this question in a 30-year longitudinal study of 3983 healthy men. We identified 52 cases that were present on entry into the study and 124 incident cases during follow-up. The incidence rose steadily after age 40 and was 1.13 per 1000 person-years over the entire period. Two thirds of the cases had only moderate prolongation of the PR interval (0.22 to 0.23 second). We compared four age-matched controls with each case for histories of scarlet fever, rheumatic fever, diphtheria, smoking, blood pressure, and body-mass index. No significant differences (P greater than 0.05) were found. Likewise, mortality from all causes did not differ between cases and controls. Although somewhat higher rates of morbidity and mortality from ischemic heart disease were observed in the cases than in the controls, the differences were not significant. Progression to higher grades of heart block occurred in only two cases. In view of the prognostic findings and the rare occurrence of advanced degrees of heart block, we conclude that primary first-degree heart block with moderate PR prolongation is a benign condition. This conclusion may not apply, however, to persons with more marked prolongation of the PR interval, a very rare condition.

Adult↗
PubMed1978

The relation of blood pressure to stroke prognosis.

The relation between blood pressure before stroke and survival after the event, was examined in the Manitoba study cohort of 3983 men. The last recorded blood pressure before the first stroke and the change in blood pressure from a measurement 5 years earlier were used. Increasing magnitude of systolic blood pressure and its 5-year changes were associated with worsening prognosis. The same association was less apparent for diastolic blood pressure and was not found for 5-year change in diastolic pressure. After adjusting for the effect of age at stroke and previous evidence of ischemic heart disease in multivariate analysis, systolic blood pressure and its 5-year change were each significant predictors of short-term (30 days) mortality. Considering all these factors as well as diastolic blood pressure, systolic blood pressure was the best predictor of short-term mortality. Thus, high blood pressure and large positive 5-year change in systolic blood pressure before stroke occurrence are significant predictors of a poor prognosis.

Adult↗
PubMed1977

Relation of body weight to development of ischemic heart disease in a cohort of young North American men after a 26 year observation period: the Manitoba Study.

The role of overweight as a risk factor for ischemic heart disease remains controversial. Therefore, in the Manitoba Study of a cohort of 3,983 men with a mean age at entry of 30.8 years, initial measurements of body weight, represented by body mass index (weight/height2), were compared with the 26 year incidence of ischemic heart disease. After adjustment for the effects of age and blood pressure in univariate and multivariate analysis, body mass index was a significant predictor of the 390 cases of ischemic heart disease. To elucidate this relation further, the cohort was further analyzed after categorization by age at entry, time of occurrence of disease after entry and manifestation of ischemic heart disease. The association with weight was most apparent in men less than 40 years of age and was not evident until 16 years of follow-up. A high body mass index was significantly associated with development of myocardial infarction, sudden death and coronary insufficiency or suspected myocardial infarction; the relation was strongest with sudden death. Among men who had a myocardial infarction, body mass index was more strongly associated with sudden death and was the best predictor of myocardial infarction occurring after 20 years of observation. Thus, after adjustment for the effect of age and blood pressure, overweight is a definite risk factor but primarily in younger men, after long periods of observation and for certain manifestations of ischemic heart disease.

Adult↗
PubMed1972

Blood pressure characteristics of a select group of North American males, followed for 20 years.

This report describes the 20-year blood pressure behaviour of 3869 selected young North American males.Initial mean systolic and diastolic pressures were higher than those recorded five years later; after that pressures increased progressively. The effect of initial selection was evident for the first 10 years of exposure.A significant relationship was demonstrated between all initial systolic and diastolic levels and the 20-year blood pressure behaviour. Systolic pressure was not affected by age until age 50 and diastolic until age 45. After that a significant relationship was demonstrated.In 20 years multiple readings >/= 140 and/or >/= 90 mm. Hg were recorded in 26% of the population. Increases in pressure usually extended over many years. Commonly they were labile, fluctuating above and below 140/90 mm. Hg. In a small, clearly defined group, accelerated increases reached high levels in three to 10 years.

Adolescent↗