Harald Vik-Mo

Influence of free fatty acids on myocardial oxygen consumption and ischemic injury

Myocardial oxygen consumption (MVO2) is influenced by the substrate supply to the heart. Utilization of free fatty acids increases MVO2, and catecholamines sensitize the heart to the oxygen-wasting effect of free fatty acids. Alteration of myocardial metabolism from mainly free fatty acid to carbohydrate oxidation reduces the extent of myocardial ischemic injury. Within the ischemic myocardium, lipolysis is stimulated with breakdown of endogenous triglycerides to fatty free acids and glycerol. Antilipolytic agents seem to have a combined effect on myocardial metabolism partly through inhibition of lipolysis in adipose tissue with reduction of free fatty acid mobilization to plasma, and partly through a local inhibition of lipolysis in the ischemic myocardium. In patients with high sympathoadrenal activity, for example, patients with acute myocardial ischemia in unstable ischemic heart disease, elevation of free fatty acids might effect a critical increase in both myocardial oxygen requirement and infarct size.

Cardiac effects of thoracic epidural analgesia before and during acute coronary artery occlusion in open-chest dogs

The effects of thoracic epidural analgesia (TEA) on myocardial performance and metabolism and on the severity of an acute myocardial ischaemia, were studied in eight anesthetized open-chest dogs. TEA reduced mean arterial blood pressure (AP) by 26%, heart rate (HR) by 20%, left ventricular dP/dt by 37%, and myocardial oxygen consumption by 27%. Although arterial concentrations of free fatty acids, glucose and lactate were unchanged, their myocardial uptake was reduced in proportion to the reduction in mechanical activity of the heart. Acute ischaemic injury was estimated from epicardial ECG recordings 10 min after occlusion of a branch of the left anterior descending coronary artery. In seven of eight dogs TEA caused a substantial reduction in the severity of the acute myocardial ischaemic injury. In the eight dogs investigated, the sum of ST segment elevations in epicardial ECG recordings was reduced from 34.0 +/- 3.4 to 23.3 +/- 2.8 mV (mean +/- SEM, P less than 0.01). After restoration of AP and HR to control values with phenylephrine and atrial pacing, the favourable effect of TEA on myocardial ischaemic injury was abolished. It is concluded that TEA effected a reduction in the severity of myocardial ischaemia in open-chest dogs, mainly through reduction of myocardial mechanical activity with consequent reduction of myocardial metabolism.

Male Breast Cancer From Pacemaker Pocket

One yeor following implantation of a mercury zinc pulse generator under the right breast, a 75‐year‐old man developed an ulcerative tumor of the nipple. Initially, the process was misinterpreted as a pacemaker pocket infection, until a diagnosis of papillary adenocarcinoma was made. The patient died from generalized metastases. To our knowledge, the association of a pacemaker implant and male breast cancer has not been previously reported; the probability of this occurring by chance seems rather low.

Mechanisms for inhibition of free fatty acid mobilization by nicotinic acid and sodium salicylate in canine subcutaneous adipose tissue in situ

Mechanisms for reduced free fatty acids (FFA) mobilization effected by nicotinic acid (NA) and sodium salicylate (SS) were studied in canine adipose tissue in situ. Both drugs inhibited adipose tissue lipolysis as evidenced by reduced release of glycerol. In addition, although the total amount of FFA re-esterified was not significantly changed, the amount of FFA re-esterified relative to the amount of FFA liberated intracellularly was significantly increased by both drugs. These effects were most pronounced during isoprenaline-stimulated lipolysis. Thus NA and SS reduced mobilization of FFA from canine adipose tissue through a combined effect on re-esterification and lipolysis.