Hemodilution decreases blood viscosity and circulatory input impedance and thus reduces afterload. Its use in treatment of LV power failure has been advocated, but the safe limits of isovolemic hemodilution are not known. Compensation of the reduced O2-capacity of the blood was therefore studied with normal and impaired coronary reserve. In 20 dogs the LAD was stenosed to a degree just not affecting the supplied region and central and coronary hemodynamics were studied. Regional myocardial function was assessed by ultrasound transit time between transducers implanted in the LV wall. Lowering the hematocrit to 15% by isovolumic exchange of blood for Dextran 60 increased CVP (18%), PAP (47%), LAP (64%), LVedP (46%), CO (67%), and flow to the intact area (LCA: 211%). Flow in the stenosed LAD increased slightly. Enddiastolic length (EDL) of LAD dependent muscle segments rose to 120% and their contraction amplitude deltaL was decreased by 46%. Whereas non-ischemic segments showed compensatory rise in deltaL (38%) at almost constant EDL (+9%). After release of the LAD stenosis EDL and deltaL returned to normal. During progressive anemia myocardial O2-demand is not adequately met if coronary reserve capacity is depleted. Reversion of hypokinesia after removal of the stenosis shows unimpaired myocardial function at a hematocrit as low as 15% provided the coronary circulation is intact.

Animals↗

PubMedDate not supplied

Atrioventricular septal defect.

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Adolescent↗

PubMedDate not supplied

Acute inferior cardiac inflow obstruction resulting from inadvertent surgical closure of a prominent Eustachian valve mistaken for an atrial septal defect.

A 5-month-old boy with a VACTERL syndrome underwent cardiac surgery for correction of a common arterial trunk and closure of an atrial septal defect. A prominent Eustachian valve was mistaken for the atrial septum and surgically closed. Thirty months later, after gradual shrinking of the foramen ovale with associated reduction of the right-to-left shunt, the boy presented with acute symptoms of a lower inflow obstruction, characterized by hepatomegaly and engorged abdominal vein pattern (Medusa's head). The boy was reoperated successfully after the condition had been recognized.

Abnormalities, Multiple↗

PubMedDate not supplied

Effect on coronary artery flow reserve and resistance in the remote area after acute coronary artery occlusion in the pig model.

BACKGROUND: It has been reported that vasodilator function in remote myocardial regions supplied by "angiographically normal" coronary arteries is impaired in patients after acute myocardial infarction (MI). The aim of this study was to determine whether coronary artery flow reserve and coronary artery resistance in remote, nonischemic areas are also altered in experimental MI. METHODS: Experiments were performed in anesthetized pigs. In group 1 infarction was induced by ligation of the left-anterior descending artery (LAD); group 2 consisted of sham-operated animals. Hemodynamic parameters, coronary artery resistance, and myocardial blood flow (MBF) were measured before and 4 hours after MI under rest and during infusion of adenosine. RESULTS: Coronary artery dilation by adenosine caused a similar increase in MBF before and 4 hours after coronary artery occlusion. Resting MBF after acute MI was not altered, although a significant reduction (15%; P < .04) in mean aortic pressure was observed compared with baseline. Coronary artery resistance was significantly reduced by adenosine (P < .04) before MI, as well as at 4 hours after MI (P < .03). Coronary artery flow reserve was not adversely affected. The sham-operated animals showed similar results without any significant differences between the two study groups. CONCLUSION: This study indicates that an acute MI in pigs did not increase coronary artery resistance in the remote area after MI and therefore did not adversely affect coronary artery flow reserve in the nonischemic vascular bed. Further studies are necessary to fully understand the exact mechanism of the alterations in remote flow reserve of patients after MI.

Adenosine↗