Rapid recovery from acute, potentially lethal myocarditis.

Two cases of acute myocarditis in young men, both with clinical and laboratory criteria indicating poor prognosis, were initially treated with conventional treatment (captopril plus metoprolol). The addition of intravenous immunoglobulin was followed by rapid clinical and laboratory recovery. This observation is considered to support previous but ambiguous evidence that autoimmune treatment may help recovery from acute myocarditis that has evidence of poor prognosis.

No effect of stem cell mobilization with GM-CSF on infarct size and left ventricular function in experimental acute myocardial infarction.

OBJECTIVES: To evaluate the effect of bone marrow pluripotent stem cell mobilization with granulocyte-monocyte colony stimulating factor (GMCSF) on infarct size and left ventricular function, in the setting of acute myocardial infarction, with a protocol easily applicable in clinical practice. METHODS: Ten pigs underwent left thoracotomy and left anterior descending coronary artery occlusion for 1 h, followed by reperfusion. After 50 min of arterial occlusion, the animals were randomly divided between treatment with placebo (Group 1) and subcutaneous GM-CSF (Group 2). The thoracotomy was closed and the animals recovered. In Group 2, GM-CSF, 20 microg/kg, was administered daily, 5 days/week, for 3 weeks. Echocardiograms were obtained at 5 and 28 days after acute myocardial infarction. At 30 days, infarct size, expressed as a percentage of the whole left ventricular mass, was measured. RESULTS: The white blood cell count increased from 13000 +/- 3338/ microl to 28700 +/- 4916/ microl (p = 0.001) in the GM-CSF-treated group. Infarct size was 7.8 +/- 6.1% in Group 1 vs 7.5 +/- 7.7% in Group 2 (ns). Similarly, no significant difference was observed between the 2 study groups in any of the echocardiographic measurements made at 28 days. CONCLUSIONS: Subcutaneous GMCSF administered during the early post acute myocardial infarction period neither decreased infarct size nor improved left ventricular function. Other protocols for mobilization of stem cells and their concentration in the injured area should be developed to combine efficacy and clinical applicability.

Moderate systemic hypotension during reperfusion reduces the coronary blood flow and increases the size of myocardial infarction in pigs.

STUDY OBJECTIVE: s: To examine the effects of low arterial BP (ABP) during reperfusion on the extent of myocardial infarction and on coronary blood flow (CBF) in an occlusion/reperfusion experimental model. DESIGN: Prospective, randomized animal study. SETTING: University hospital. PARTICIPANTS: Normal pigs that were anesthetized, intubated, and mechanically ventilated. INTERVENTIONS: Twenty-seven open-chest pigs underwent occlusion of the mid left anterior descending (LAD) coronary artery for 1 h followed by reperfusion for 2 h. During reperfusion, the animals were randomly assigned to either continuous infusion of nitroglycerin in therapeutic doses and fluid infusion at rates to maintain a mean ABP >or= 80 mm Hg (group 1, n = 13), or continuous nitroglycerin infusion at rates to maintain a mean ABP between 60 mm Hg and 75 mm Hg (group 2, n = 14). MEASUREMENTS AND RESULTS: The hemodynamics and the coronary ABP distal to the occlusion were recorded throughout the experiment. In addition, the LAD CBF and peak hyperemia CBF before occlusion and during reperfusion periods were measured by transit-time flowmetry. At the end of the experiment, the infarcted left ventricular myocardial size was measured. There were no significant hemodynamic differences, including the distal coronary arterial pressure, between the two groups before or during the LAD artery occlusion period. During reperfusion, mean ABP was 90 +/- 3 mm Hg in group 1 vs 69 +/- 3 mm Hg in group 2 (p < 0.001). In group 1, the infarcted myocardium represented 50.3 +/- 4.3% of the myocardium at risk, vs 69.4 +/- 7.2% in group 2 (p < 0.001). During reperfusion, CBF and peak hyperemia CBF were significantly higher in group 1 than in group 2. CONCLUSIONS: Low ABP during reperfusion increases the size of myocardial infarction and decreases CBF.