SUMMARY To delineate the effects of true aging, undetected heart disease and deconditioning on heart rate, we performed 24-hour ambulatory electrocardiography and maximal exercise stress test on 101 subjects with normal hearts. The maximal heart rate recorded was 180 beats/min; the minimum was 35 beats/min. A distinct diurnal pattern was observed.With increasing age, a decrease of the maximal heart rate achieved during exercise stress test (r = 0.27,p = 0.05) or spontaneously recorded during the day (r = 0.41, p = 0.0005) or night (r = 0.24, p = 0.03) was observed. The resting and average heart rates were not affected by age. Older subjects had lower exercise tolerance (r = 0.41, p = 0.0001). Low exercise tolerance was associated with higher increments of heart rate for submaximal exercise levels (r = 0.53, p = 0.001), steeper increase of heart rate with increasing intensity of exercise (r = 0.68, p = 0.0001) and lower maximal heart rates (r = 0.43, p = 0.008).These changes of heart rate with age are not due to undetected cardiac disease, because the subjects included in the study were meticulously screened by noninvasive and invasive means.MANY STUDIES have shown that the maximal exercise heart rate declines with age.18 The intrinsic heart rate after autonomic blockade with atropine and propranolol also decreases with age with a slope similar to that of the maximal exercise heart rate.9 However, the average daily heart rate is not influenced by age,'0 and contradictory or few data are available on the effect of age on resting heart rate, on the increment of heart rate induced by standardized exercise and on the diurnal variation of heart rate." 64,[10][11][12][13][14][15][16][17][18] A common problem in studying the effect of age on the heart is the difficulty in separating the true effects of aging from those due to deconditioning or unrecognized diseases. Deconditioning due to sedentary lifestyle is a common accompaniment of aging, and undetected significant coronary artery disease may be present in more than one-fourth of persons older than 45 years of age.9-22In the studies mentioned above, the effect of age cannot be clearly distinguished from the effects of subclinical coronary artery disease or deconditioning. To further define the effect of age on the heart rate, we performed 24-hour ambulatory electrocardiography and maximal exercise stress testing on 101 subjects free of detectable heart disease verified by extensive noninvasive and invasive testing. Materials and Methods PopulationOne hundred one subjects with normal hearts were identified among 1500 patients referred for cardiac From

Myocardial infarction presenting solely as an acute, severe headache is underdiagnosed in elderly patients. In patients over 80 years of age, myocardial infarction presents more commonly with atypical symptoms than with chest pain. The authors describe two patients who presented with headache as the only symptom of an acute myocardial infarction. The authors recommend that acute myocardial infarction be considered in the differential diagnosis of acute, severe headache in elderly patients.

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Clinical and scintigraphic findings are described in a patient in whom acute right-sided pulmonary edema developed during a treadmill exercise test. The patient's SPECT Tl-201 stress images are reviewed along with the pertinent clinical history. The development of unilateral pulmonary edema during an exercise treadmill test was demonstrated with Tl-201 imaging.

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