Doppler color flow imaging in detection and mapping of left coronary artery fistula to right ventricle and atrium.

Two patients who had left coronary artery fistulas that drained into the right ventricle (case 1) and right atrium (case 2) were studied with combined two-dimensional echocardiography and Doppler color flow imaging. The origin of the fistulas from the left coronary artery, their course, and drainage sites were readily identified. These cases illustrate the enhanced identification of left coronary artery fistulas and the drainage sites with the addition of Doppler color flow imaging to two-dimensional echocardiography.

Increased platelet thromboxane A2/prostaglandin H2 receptors in patients with acute myocardial infarction.

Platelets have been implicated in the formation of occlusive intracoronary thrombi leading to unstable angina pectoris and acute myocardial infarction. Evidence of platelet involvement in these syndromes includes increased thromboxane A2 synthesis during ischemic events and enhanced in vitro sensitivity to agonists. To determine the density and affinity of platelet thromboxane A2/prostaglandin H2 (TXA2/PGH2) receptors in patients with acute myocardial infarction and unstable angina pectoris, the maximum number of binding sites (Bmax) per platelet and the dissociation constant (Kd) of the TXA2/PGH2 receptor antagonist, [125I]-PTA-OH, was determined at equilibrium in washed platelets. Patients with acute myocardial infarction had a significantly (p = 0.006) higher Bmax (4,468 +/- 672 sites/platelet, n = 9) compared with controls (2,206 +/- 203 sites/platelet, n = 8). Restudied at a time when the patients' coronary artery disease was clinically stable, Bmax values for the myocardial infarction group had returned to within normal limits. The dissociation constant for [125I]-PTA-OH was not significantly different in the acute myocardial infarction patients compared with controls. In patients with acute myocardial infarction, the duration of chest pain was positively correlated (r = 0.71, p less than 0.02) with the number of [125I]-PTA-OH binding sites (Bmax). In vitro platelet sensitivity to the TXA2/PGH2 mimetic, U46619, was assessed in aggregation studies. The maximal velocity of aggregation (slope) correlated with platelet TXA2/PGH2 receptor number (r = 0.67, p less than 0.001) and was significantly higher (p less than 0.02) in the acute myocardial infarction patients compared with the other study groups. There was no significant difference in the aggregation EC50 values for the thromboxane mimetic U46619 between unstable angina, acute myocardial infarction, and control groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Intravenous streptokinase therapy for acute myocardial infarction in a community hospital: effect on ventricular function and mortality.

Streptokinase can dramatically impact upon management of myocardial infarctions in community hospitals. When given by experienced personnel during the first six hours after onset of symptoms, streptokinase is associated with a high patency rate, improved left ventricular function, and reduced mortality. Careful screening of patients results in a low complication rate with infrequent serious bleeding. Streptokinase should be utilized in those hospitals without cardiac catheterization facilities, but in light of the relatively high incidence of recurrent pain (15.8%), transfer of stable patients to a facility with a catheterization laboratory should be carried out within 24 to 72 hours. As approximately 60% of patients will require PTCA, CABG, or both, diagnostic cardiac catheterization should be considered in all patients unless there are other mitigating factors.