These findings indicate that dynamic exercise may be an important adjunct in the treatment of mild hypertension.

Long-term follow-up of 101 healthy elderly subjects living independently in the community has been undertaken by means of clinical examination, resting ECG and 24-hour ambulatory cardiac monitoring. It appears that the finding of ventricular premature complexes at the rate of 10 per hour or greater is associated with a significant increase in mortality. The prevalence of atrial fibrillation, initially found to be 11%, rises with age to 17% by the age of 84 years. Long-term ambulatory monitoring is essential in the proper documentation of paroxysmal atrial fibrillation. Bundle branch block also occurs in over 10% of elderly people and the prevalence rises steeply with age, so that at the end of this study more than one quarter of the survivors had evidence of His-Purkinje disease. Over 5% of our subjects had definite indications for pacing during the period of follow-up and lends support to the opinion that the current pacemaker implantation rate in the United Kingdom is below the optimal level.

To resolve conflicting reports concerning the effects of beta-blockade (BB) on thermoregulatory reflexes during exercise, we studied six fit men during 40 min of cycle ergometer exercise at 60% maximum O2 consumption at ambient temperatures of 22 and 32 degrees C. Two hours before exercise, each subject ingested a capsule containing either 80 mg of propranolol or placebo in single-blind fashion. Heart rate at 40 min of exercise was reduced (P less than 0.01) from 125 to 103 beats min at 22 degrees C and 137 to 104 beats min at 32 degrees C, demonstrating effective BB. After 40 min of exercise, esophageal temperature (Tes) was elevated with BB (P less than 0.05) from 37.66 +/- 0.04 to 38.14 +/- 0.03 and 38.13 +/- 0.04 to 38.41 +/- 0.04 degrees C at 22 and 32 degrees C, respectively. The elevated Tes resulted from a reduced core-to-skin heat flux at both temperatures, indicated by a reduction in the slope of the forearm blood flow (FBF)-Tes relationship, and a decrease in maximal FBF. Systolic blood pressure was decreased 20 mmHg with BB (P less than 0.01), whereas diastolic blood pressure was unchanged, reducing arterial pulse pressure (PP). Because PP was decreased and cardiac filling pressure was presumably not reduced (since cardiac stroke volume was elevated), we suggest that at least a part of the relative increase in peripheral vasomotor tone during BB was the consequence of reduced sinoaortic baroreceptor stimulation.

Nickel was measured, by electrothermal atomic absorption spectrophotometry, in sera from (a) 30 healthy adults, (b) 54 patients with acute myocardial infarction, (c) 33 patients with unstable angina pectoris without infarction, and (d) five patients with coronary atherosclerosis who developed cardiac ischemia during treadmill exercise. Mean (and SD) concentrations in Group a were 0.3 (0.3) microgram/L (range less than 0.05-1.1 microgram/L). Within 72 h after hospital admission, hypernickelemia (Ni greater than or equal to 1.2 microgram/L) was found in 41 patients of group b (76%) and in 16 patients of group c (48%). Hypernickelemia was found before and after exercise in one patient of Group d (20%). Peak values averaged 3.0 micrograms/L (range 0.4-21 micrograms/L) in Group b, 1.5 microgram/L (range less than 0.05-3.3 micrograms/L) in Group c. In Group b, the mean time interval between the peak values for creatine kinase activity and for nickel was 18 h. Serum nickel concentrations were unrelated to age, sex, time of day, cigarette smoking, medications, clinical complications, or outcome. Mechanisms and sources of release of nickel into the serum of patients with acute myocardial infarction or unstable angina pectoris are conjectural, but hypernickelemia may be related to the pathogenesis of ischemic myocardial injury.

No abstract