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To evaluate the possible irreversibility of isometric exercise-induced left ventricular dysfunction in aortic regurgitation, we performed handgrip exercise tests during cardiac catheterization on 17 patients with chronic aortic regurgitation (AR-group), both preoperatively and one year after successful aortic valve replacement. Nine normal subjects served as a control group. Preoperatively, the ejection fraction decreased from 59 ± 7% to 53 ± 8% (P<0.001) in the AR-group while it remained unchanged in the control group during exercise. A positive correlation existed between the changes in the ejection fraction during pre- and postoperative exercise tests (r = 0.85, P < 0.001), which revealed that in patients with severely depressed ejection fraction during the preoperative exercise test, the ventricular response to exercise was not totally corrected after surgery. The regression of left ventricular mass was also smaller in the patients with most depressed ventricular response to exercise preoperatively. As the isometric exercise-induced left ventricular dysfunction appears to be partly irreversible, we conclude that the valve replacement should perhaps be performed before stress-induced ventricular dysfunction has occurred. Non-invasive monitoring of ventricular response to exercise might be helpful in optimizing the timing of valve replacement in aortic regurgitation. [ABSTRACT FROM PUBLISHER]

The inter-relationships between ischaemia-induced metabolic changes and atrial natriuretic peptide (ANP) release were studied in 18 patients undergoing elective percutaneous transluminal coronary angioplasty (PTC A). Transcardiac differences in ANP, lactate, pH, pCO and O saturation were analysed before and after balloon inflation. The patients were divided into ischaemia and non-ischaemia groups on the basis of the change in lactate extraction ratio during balloon inflation. The ischaemia group (patients with a decrease in lactate extraction ratio) showed an increase of 27±15 pg. ml in the transcardiac ANP difference, whereas a decrease of 27±17pg.ml occurred in the non-ischaemia group (no decrease in lactate extraction ratio). The change between the two patient groups was statistically significant (<0.05). Metabolic ‘pre-conditioning’ was not observed in (P<0.05) was obtained between the PTCA-induced changes in transcardiac ANP and lactate differences. We conclude that transient myocardial ischaemia induced by PTCA increases circulating ANP concentrations in patients with signs of metabolic ischaemia, but not in those without. [ABSTRACT FROM PUBLISHER]

Oral anticoagulant therapy with warfarin commenced pre-operatively (n = 102) to prevent coronary artery vein graft occlusions was compared in terms of efficacy and safety with dipyridamole and aspirin (n = 130) in a randomized consecutive series of patients. Anticoagulant therapy was started at least 2 weeks before coronary artery bypass surgery (CA BG) and antiplatelet therapy was started at least 3 days before CA BG with dipyridamole followed by a combination of 250 mg aspirin once a day via a nasogastric tube 6 h after CABG. Overall, vein graft patency at 3 months after surgery did not differ significantly between the anticoagulant group (203/275, 74%) and dipyridamole-aspirin group (238/311, 77%), but the occlusion rate for grafts with endarterectomy was higher in the anticoagulant (46%) than in the dipyridamole and aspirin group (16%), (P<0·05). The rate of peri-operative complications including deaths, re-operation and myocardial infarction was higher in the anticoagulant than antiplatelet group (26·5% vs 13·8%, P < 0·05). The occurrence of postoperative bleeding complications did not differ significantly between the groups. Thus, oral anticoagulant therapy commenced pre-operatively has no advantages over conventional antiplatelet therapy in patients who undergo CABG. Neither antithrombotic regimens proved to be satisfactory for preventing acute bypass vein graft occlusions in this patient population with advanced coronary artery disease. [ABSTRACT FROM PUBLISHER]

Low heart rate variability (HRV) is a predictor of a poor outcome after myocardial infarction. To determine whether coronary artery bypass grafting (CABG) has any effect on H RV, the power spectrum components of HRV were measured in 35 patients before, and J week after, CA BG. Significant attenuation of all spectral components of HR V were found after CABG (P<0.001). High frequency (HF) power decreased to one third of the preoperative level, mid-frequency (MF) power to as little as one fifteenth and low frequency (LF) power to one seventh of the preoperative level. No significant restoration in MF or HF powers occurred during the 6-week follow-up period. The results suggest that CABG causes a marked attenuation of HRV. The prognostic significance of this attenuation is not known. [ABSTRACT FROM PUBLISHER]