The preceding article in this series 1 reviewed evidence as to why age-associated changes in the central arterial system are risky with respect to vascular disease. In a similar vane, the focus of this article is on the potential link between ageassociated changes in the heart and clinical cardiac disease outcomes.Left ventricular hypertrophy, heart failure, and atrial fibrillation increase dramatically with age ( Figure 1). The prevalence of left ventricular hypertrophy (LVH) also increases with rising blood pressure and body mass index, a measure of obesity. [2][3][4] Whether identified by electrocardiography or echocardiography, left ventricular hypertrophy has been shown to be associated with increased risk for coronary heart disease, sudden death, stroke, and overall cardiovascular disease. 4,5 It has been increasingly appreciated that the development of heart failure with apparently preserved systolic function, as evidenced by a "normal" ejection fraction, occurs in about one-third to one-half of older patients with heart failure. 6 -9 In a patient with heart failure, a diagnosis of diastolic heart failure can be inferred, largely by exclusion, when other comorbidities that masquerade as heart failure are ruled out and left ventricular ejection fraction is intact. 10 Atrial fibrillation (AF) is detected in approximately 3% to 4% of healthy volunteers over age 60 years who are rigorously screened to exclude clinical coronary artery disease; this is a rate 10-fold higher than in the general adult population. 11,12 In the Framingham population, a history of AF without identifiable cause (so-called "lone" AF) was present 16.8% of men and 6.0% of women with AF at a mean age of about 70 years. 12 During long-term follow-up, individuals with lone AF suffered over 4 times as many strokes as control subjects, although their rates of coronary events or congestive heart failure were similar to those of controls. The proportion of AF cases that occur in the absence of an identifiable cause differs between studies. These differences are due to differences in characteristics of subjects and the rigor with which underlying causes are sought.
Age-Associated Changes in Cardiac Structure and Function in Persons Without a Heart Disease DiagnosisThere is a continuum of expression of cardiac structural and functional alterations that occurs with age in healthy humans, and these age-associated cardiac changes seem to have relevance to the steep increases in LVH, chronic heart failure, and AF seen with increasing age.
Cardiac StructureCross-sectional studies of subjects without hypertension or clinically apparent cardiovascular disease indicate that left ventricular (LV) wall thickness, measured via M-mode echocardiography, increases progressively with age in both sexes ( Figure 2A). In older hospitalized patients without apparent cardiovascular disease, in whom overall LV mass was not increased, cardiac myocyte enlargement was observed at autopsy, along with an decrease in the estimated myocyte number that was greater in males...