Luc Vanhees

Secondary prevention with beta-adrenoceptor blockers in post-myocardial infarction patients

Abstract The 12 placebo controlled double-blind trials with beta-adrenergic blocking agents in post-MI patients were reviewed separately and the results were combined. The results of every single trial were compatible with the statement that beta blockade decreased total mortality by 20% to 30% in these post-MI patients. This was mainly related to a decrease in cardiac mortality, in particular sudden death. Reinfarctions were also reduced. Withdrawal for adverse reactions was higher in the beta blocker than in the control group. Beta blockade can therefore be considered as a potential treatment for secondary prevention in selected post-MI patients.

Carotid baroreceptor control of heart rate and physical fitness

The carotid sinus baroreceptor reflex control of heart rate was studied in 12 endurance runners, 12 matched controls and in 24 cycling tourists using a variable negative pressure applied through a neck chamber. Baroreflex sensitivity was expressed as the slope of the linear relationship between the strength of the stimulus and the maximal lengthening of the RR interval on the electrocardiogram. Baroreflex sensitivity averaged 6.8 ± 1.1 (SEM) msec/mm Hg in controls, 10.3 ± 1.8 in runners and 7.3 ± 0.8 msec/mm Hg in cycling tourists. No significant differences were observed between the three groups. In single and multiple regression analysis, no significant relationship was found between carotid baroreflex sensitivity and age, blood pressure, resting heart rate, peak oxygen uptake and characteristics of training.

Sports and hypertension

Physical training of the hypertensive patient is likely to cause a slight decrease of blood pressure and can therefore be advocated as part of the non-pharmacological management of the patient or as an adjunct to pharmacological treatment. However, because of the possible risks involved, and also to better define the desired training intensity particularly in treated patients, an exercise test is recommended.

Correlates of the effect of physical training in cardiac patients

A retrospective analysis was performed in 118 patients with heart disease, who were trained for 3 months. Peak oxygen uptake (VO2) increased with 38%. Multiple regression analysis revealed that the gain in peak oxygen uptake after the training program was more important when the initial peak oxygen uptake was low, when a history of angina and dyspnoea were absent and when the training intensity and frequency was high (R = 0.62). It was not related to the type of myocardial infarction, peak CPK, cardiac function, medical treatment, ST depression or arrhythmias.