BACKGROUND
Many secondary abnormalities in chronic heart failure (CHF) may reflect physical deconditioning. There has been no prospective, controlled study of the effects of physical training on hemodynamics and autonomic function in CHF.
METHODS AND RESULTS
In a controlled crossover trial of 8 weeks of exercise training, 17 men with stable moderate to severe CHF (age, 61.8 +/- 1.5 years; left ventricular ejection fraction, 19.6 +/- 2.3%), increased exercise tolerance (13.9 +/- 1.0 to 16.5 +/- 1.0 minutes, p less than 0.001), and peak oxygen uptake (13.2 +/- 0.9 to 15.6 +/- 1.0 ml/kg/min, p less than 0.01) significantly compared with controls. Training increased cardiac output at submaximal (5.9-6.7 l/min, p less than 0.05) and peak exercise (6.3-7.1 l/min, p less than 0.05), with a significant reduction in systemic vascular resistance. Training reduced minute ventilation and the slope relating minute ventilation to carbon dioxide production (-10.5%, p less than 0.05). Sympathovagal balance was altered by physical training when assessed by three methods: 1) RR variability (+19.2%, p less than 0.05); 2) autoregressive power spectral analysis of the resting ECG divided into low-frequency (-21.2%, p less than 0.01) and high-frequency (+51.3%, p less than 0.05) components; and 3) whole-body radiolabeled norepinephrine spillover (-16%, p less than 0.05). These measurements all showed a significant shift away from sympathetic toward enhanced vagal activity after training.
CONCLUSIONS
Carefully selected patients with moderate to severe CHF can achieve significant, worthwhile improvements with exercise training. Physical deconditioning may be partly responsible for some of the associated abnormalities and exercise limitation of CHF, including abnormalities in autonomic balance.
We have evaluated overall and cardiac sympathetic activity in 47 patients undergoing coronary angiography, 27 with stable angina of at least 3 months duration, and 20 with unstable ischaemic symptoms within this period. Cardiac and overall sympathetic activity were assessed using radiotracer noradrenaline kinetic techniques to measure cardiac and total noradrenaline spillover to plasma. Overall sympathetic activity (whole body noradrenaline spillover) was similar in the two groups, whereas cardiac sympathetic activity (cardiac noradrenaline spillover) was strikingly increased in the patients with unstable ischaemic symptoms (102 +/- 23 pmol.min-1 vs 34 +/- 4 pmol.min-1, P < 0.001), as was the cardiac to whole body noradrenaline spillover ratio (0.043 +/- 0.008 vs 0.021 +/- 0.005, P < 0.01). Coronary sinus bloodflow (50 +/- 4 ml.min-1 vs 38 +/- 4 ml.min-1, P < 0.05) and coronary sinus noradrenaline concentration (2.60 +/- 0.38 nmol.l-1 vs 1.41 +/- 0.17 nmol.l-1, P < 0.01) were also increased in the patients with unstable ischemic syndromes. Left ventricular ejection fraction was similar in the two groups (63 +/- 2% vs 62 +/- 2%). Patients with unstable ischaemic symptoms within the previous three months have increased cardiac sympathetic nervous activity compared to patients with stable angina. This may in part explain why patients with unstable ischaemic syndromes are at increased risk of sudden cardiac death.
The aim of this study was to assess the quality of angiograms obtained using 4 Fr catheters compared with 6 Fr catheters, the ease of use of the 4 Fr catheters, and the safety of patient mobilization 1 hr following 4 Fr angiography. Details of catheter performance and procedural details were recorded at the time of the angiogram. The angiographic images were scored on the quality and completeness of vessel opacification throughout systole and diastole. A total of 410 patients were recruited. There was no difference between 4 and 6 Fr for procedural variables. All angiograms were considered to be of diagnostic quality. The angiographic scores for the right coronary artery and left ventricular injections were no different between 4 and 6 Fr. However, the angiographic scores for the left anterior descending and circumflex arteries were lower with 4 than with 6 Fr (both P < 0.05). Patients who had 4 Fr angiography mobilized safely at 1 hr and reported significantly less discomfort and bruising than 6 Fr patients. Good-quality diagnostic coronary angiograms can be achieved using 4 Fr catheters with the advantage of earlier postprocedural mobilization and reduced discomfort and bruising for the patient.
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