Toward the optimal lead system and optimal criteria for exercise electrocardiography

To define the optimal lead system for exercise electrocardiography, data of the whole body surface potential distribution were analyzed in 25 normal subjects and in 25 patients with coronary artery disease at rest and during exercise. All patients had a normal electrocardiogram at rest. The sensitivity of the standard chest leads was 60 percent; it improved to 84 percent with the body surface map whereas both methods had a 100 percent specificity. On the basis of these data, and reports from other centers, it is concluded that a single bipolar lead from the right subclavian area to lead V5 is adequate in those laboratories that are restricted to testing subjects with a normal electrocardiogram at rest. In patients with a previous infarction or other abnormalities in the electrocardiogram at rest three (pseudo) orthogonal leads or several standard leads are necessary. Recommendations for optimal measurements from the exercise electrocardiogram are based on quantitative computer analysis of the selected leads in larger groups of patients. Best results were obtained with a combination of S-T amplitude, S-T slope and heart rate. The improvement in sensitivity from 50 percent with visual analysis to 85 percent with computer was similar to that obtained with body surface mapping. Changes of the P wave and QRS complex during exercise appeared to be of little diagnostic value. The pathophysiologic mechanisms that contribute to the changes of the electrocardiogram during exercise are discussed

Exercise training and heart rate variability in older people

Purpose: Heart rate variability (HRV), a characteristic that is potentially increased by physical activity, has been associated with incidence of cardiac events and total mortality. Since the incidence of cardiac events among older people is high and their physical activity levels and HRV are generally low, it is important to investigate whether regular physical activity can modify HRV in this age group. The purpose of the study was to investigate the effect of regular physical activity on HRV in older men and women. Methods: In a randomized controlled trial, the effect of six months' training on HRV was investigated in a group of 51 older men and women (67.0 ± 5.1 yr). The training group gathered three times per week for 45 min supervised training. Results: At the end of the intervention period, HRV was higher primarily during the day. During daytime, the SD of all normal intervals (+ 6%) as well as the low frequency component (+ 15%) and the very low frequency component (+ 10%) of HRV were significantly increased (P < 0.05) as compared with the control group. Effects of training were most pronounced in subjects inactive in sports at baseline. Conclusion: This study demonstrates that regular physical activity increases HRV (specifically in the very low and low frequency components) in older subjects. Hence, in older subjects, physical training may be an effective means to modify positively a factor that is associated with increased incidence of cardiac events

Exercise training and heart rate variability in older people

Purpose: Heart rate variability (HRV), a characteristic that is potentially increased by physical activity, has been associated with incidence of cardiac events and total mortality. Since the incidence of cardiac events among older people is high and their physical activity levels and HRV are generally low, it is important to investigate whether regular physical activity can modify HRV in this age group. The purpose of the study was to investigate the effect of regular physical activity on HRV in older men and women. Methods: In a randomized controlled trial, the effect of six months' training on HRV was investigated in a group of 51 older men and women (67.0 ± 5.1 yr). The training group gathered three times per week for 45 min supervised training. Results: At the end of the intervention period, HRV was higher primarily during the day. During daytime, the SD of all normal intervals (+ 6%) as well as the low frequency component (+ 15%) and the very low frequency component (+ 10%) of HRV were significantly increased (P < 0.05) as compared with the control group. Effects of training were most pronounced in subjects inactive in sports at baseline. Conclusion: This study demonstrates that regular physical activity increases HRV (specifically in the very low and low frequency components) in older subjects. Hence, in older subjects, physical training may be an effective means to modify positively a factor that is associated with increased incidence of cardiac events

Effect of physical training on QTc interval in elderly people

In order to assess whether heart rate-adjusted QT duration (QTc) is reduced by physical activity in an elderly population, a randomized, controlled intervention study of the effect of a 6-month intensive training program on QTc was undertaken. The participants were 229 healthy men and women, aged 60-80 years. The subjects of the intervention group trained three to four times a week at a work load of about 70% of their maximum capacity for 6 months, while the control subjects maintained their habitual activities. The main outcome measures were change in QTc and resting heart rate. For women, the mean QTc interval (ms) of the intervention group changed by -6.7 (SE 2.8) versus 0.6 (SE 2.4) in the control group (P = .05), while for men, the change in the intervention group subjects was -2.7 (SE 2.2) versus 0.4 (SE 3.1) in the control subjects (P = .39). Also, resting heart rate (beats/ min) changed in intervention group women by -4.6 (SE 1.7) as against -0.06 (SE 1.1) in the control subjects (P = .02), and in intervention group men it changed by -3.2 (SE 1.2) versus -0.9 (SE 1.5) in the control subjects (P = .25). These data indicate that regular physical activity favorably affects QTc in elderly women. A similar, but not significant, trend was observed in men. The beneficial shift in QTc may be caused by a more favorable autonomic balance through increased parasympathetic activity. The reduced resting heart rate in subjects of the intervention group supports this view. Although the reduction was relatively small, it may represent a favorable effect on cardiovascular risk

Chest pain and angina pectoris - or the ugly swan and the beautiful duckling

The original description of Heberden’s angina pectoris is put forward to stress the importance of proper history-taking in identifying patients. In a market-driven approach to improve cost-effectiveness in healthcare, angina pectoris as an entity seems stripped to its bare minimum: chest and pain. The diagnostic yield of exercise testing, however, depends on the pre-test likelihood of disease and therefore knowledge of its clinical utility and pitfalls is essential to refine an initial and subjective diagnosis based on anamnesis. Nowadays chest pain units attempt to improve diagnostic accuracy by submitting all sorts of patients to the (stress) test. In the end protocol-driven policies like these may very well prove to be contraproductive when fundamentals are ignored. (Neth Heart J 2010;18:561–4.