Coronary-artery revascularization before elective vascular surgery does not significantly alter the long-term outcome. On the basis of these data, a strategy of coronary-artery revascularization before elective vascular surgery among patients with stable cardiac symptoms cannot be recommended.
Digoxin did not reduce overall mortality, but it reduced the rate of hospitalization both overall and for worsening heart failure. These findings define more precisely the role of digoxin in the management of chronic heart failure.
Among patients with coronary artery disease who undergo vascular surgery, a peri-operative elevation in cardiac troponin levels is common and in combination with diabetes, is a strong predictor of long-term mortality. These data support the utility of cardiac troponins as a means of stratifying high-risk patients following vascular operations.
Expanded use of exercise heart rate recovery (HRR) has renewed interest in the pathophysiology of heart rate control. This study uses basic physiologic principles to construct a unique model capable of describing the full time course of sympathetic and parasympathetic activity during HRR. The model is tested in a new study of 22 diverse subjects undergoing both maximal and submaximal treadmill exercise. Based on this analysis, prolongation of HRR involves changes within the sinus node, changes in sympathetic function, in parasympathetic function, and in the central mechanisms regulating autonomic balance. The methods may provide unique insight into alterations in autonomic control in health and disease.
Since ischemic heart disease (IHD) is inhomogeneous, the adrenergic response of the heart to ischemia or infarction could depend on the level of adrenergic supply within specific regions of the myocardium. Therefore we quantified myocardial norepinephrine (NE) content of tissue samples from 54 different sites in the left ventricle (LV) of four normal dogs using high-pressure liquid chromatography with electrochemical detection. Up to 10-fold differences in NE content occurred within a single LV. The NE distribution followed a consistent pattern, demonstrating a gradient from apex (avg minimum value of 162 ng/g of tissue) to base (avg maximum value 844 ng/g). No epicardial-to-endocardial gradient was present. In six other dogs a similar pattern was found in myocardial uptake of radioactively labeled NE and epinephrine assessed 2 min after intravenous injection. These results suggest that areas of high tissue NE represent regions rich in adrenergic supply and high in adrenergic activity, not merely NE stored in inactive pools. Samples from a human autopsy specimen suggest that these findings can be extrapolated to humans.
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