Influence of age on left ventricular contractility.
Controversy exists about whether left ventricular (LV) function is affected by aging. Therefore, peak systolic pressure to end-systolic diameter, peak systolic pressure to end-systolic volume, systolic wall stress to fractional shortening and systolic wall stress to end-systolic diameter relations were calculated in the left ventricle of 10 healthy subjects greater than 65 years old (age 70 +/- 4 years) (group B). They were compared with a control group composed by 10 healthy subjects (group A, age 22 +/- 1 years). LV measurements were obtained with M-mode echocardiography and an automatic cuff was used to determine blood pressure. Changes in the load conditions were obtained by 15 mg sublingual isosorbide dinitrate. There were no differences in resting end-systolic diameter, end-systolic volume, end-diastolic diameter, end-diastolic volume, fractional shortening, ejection fraction or systolic wall stress. Older subjects had higher values of resting peak systolic pressure (p less than 0.05) and lower heart rates (p less than 0.05). Young subjects had a steeper peak systolic pressure to end-systolic diameter slope (92 +/- 11 vs 51 +/- 11 mm Hg/cm; p less than 0.001) and peak systolic pressure to end-systolic volume slope (3.4 +/- 0.7 vs 1.9 +/- 0.6 mm Hg/ml; p less than 0.001). There was a slight difference in systolic wall stress to fractional shortening slopes between both groups (group A -0.215 vs group B -0.49%/10(3) dynes/cm2, p = 0.02) but not between systolic wall stress to end-systolic diameter slopes (group A 0.013 vs group B 0.019 cm/10(3) dynes/cm2, difference not significant).(ABSTRACT TRUNCATED AT 250 WORDS)
Merino
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A
Departamento de Cardiología y Cirugía Cardiovascular, Universidad de Navarra, Pamplona, Spain.
Alegría
E
E
Castelló
R
R
Martínez-Caro
D
D
D000222:Adaptation, Physiological; D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D001794:Blood Pressure; D004452:Echocardiography; D006339:Heart Rate; D006801:Humans; D009200:Myocardial Contraction; D013318:Stroke Volume