To define the prevalence of total coronary occlusion in the hours after transmural myocardial infarction, we used coronary arteriography to study the degree of coronary obstruction in 322 patients admitted within 24 hours of infarction. Total coronary occlusion was observed in 110 of 126 patients (87 per cent) who were evaluated within four hours of the onset of symptoms; this proportion decreased significantly, to 37 of 57 (65 per cent), when patients were studied 12 to 24 hours after the onset of symptoms. Among 59 patients with angiographic features of coronary thrombosis, the thrombus was retrieved by Fogarty catheter in 52 (88 per cent) but was absent in seven (12 per cent false positive). Among an additional 20 patients without angiographic features of thrombosis, a thrombus was discovered in five (25 per cent false negative). Thus, total coronary occlusion is frequent during the early hours of transmural infarction and decreases in frequency during the initial 24 hours, suggesting that coronary spasm or thrombus formation with subsequent recanalization or both may be important in the evolution of infarction.

No abstract

Complete occlusion of the infarct-related coronary artery is a frequent finding soon after Q-wave (transmural) myocardial infarction. We performed coronary arteriography to study the frequency of total coronary occlusion and of angiographically visible collateral vessels in 341 patients within one week of non-Q-wave myocardial infarction. In this cross-sectional study, 192, 94, and 55 patients underwent coronary arteriography within 24 hours of peak symptoms, between 24 and 72 hours after peak symptoms, and between 72 hours and seven days after peak symptoms, respectively. In the three groups, total occlusion of the infarct-related vessel was found in 26 percent (49 of 192), 37 percent (35 of 94), and 42 percent (23 of 55) of the patients, respectively (P less than 0.05). The presence of visible collateral vessels increased in parallel: 27 percent (52 of 192), 34 percent (32 of 94), and 42 percent (23 of 55), respectively (P less than 0.05). The frequency of subtotal occlusion (i.e., greater than or equal to 90 percent stenosis) decreased inversely: 34 percent (65 of 192), 25.5 percent (24 of 94), and 18 percent (10 of 55), respectively (P less than 0.05). Thus, in contrast to Q-wave infarction, total coronary occlusion of the infarct-related vessel is infrequently observed in the early hours of non-Q-wave infarction, but it increases moderately in frequency over the next several days. These cross-sectional data suggest that non-Q-wave infarction may be related to a preserved but marginal blood supply, which sufficiently disrupts the relation between the supply of and the demand for myocardial oxygen to cause tissue necrosis.

No abstract

Based on outcomes at hospital discharge or 30 days, primary angioplasty appears to be superior to thrombolytic therapy for treatment of patients with acute myocardial infarction, with the proviso that success rates for angioplasty are as good as those achieved in these trials. Data evaluating longer-term outcomes, operator experience, and time delay before treatment are needed before primary angioplasty can be universally recommended as the preferred treatment.

Summary:The purpose of this study was to compare the hemodynamic and clinical effects of milrinone, a vasodilating and positive inotropic agent, with those of dobutamine in patients with congestive heart failure (CHF) following acute myocardial infarction (AMI). Thirty-three patients in Killip classification I1 or I11 within 12 h to S days after AM1 were randomized in a multicenter, open-label clinical trial to receive a 23-h inhsion of milrinone ordobutamine. Drugs were titrated to achieve at least a 3 0 8 increase in cardiac index (CI) from mean baseline or at least a 25% decrease in mean pulmonary capillary wedge pressure (MPCWP) from baseline. Both drugs improved CI, M E W , and other hemodynamic parameters. Criteria for decrease in MPCWP were met by 94%( IS/ 16) of the milrinone-treated patients and 57% (8/l4) of dobutamine-treated patients (p = 0.03). Both groups met the minimum efficacy criterion for CI. Maximal reduction in MPCWP over G 3 h was greater in the milrinone group (-53.2%) thanin thedobutaminegroup(-31.0%;pS0.01); reductions were sustained over 24 h. Both drugs improved echocardiographic global ejection fraction and were generally well tolerated. The short-term infusion of milrinone may have Part ol'this work has been published previously in abstract form and was presented at the 65th Scientific Session of the American Heart Association, New Orleans. La.

To study the safety and efficacy of a new medical food (Theramine) in the treatment of low back pain, we performed a 28-day double-blind randomized controlled trial in 129 patients. Back pain was present for at least 6 weeks and was not mild. Patients were randomly assigned to receive medical food alone (n = 43), naproxen alone (250 mg/d, n = 42), or both medical food and naproxen (n = 44). All patients were assessed by using Roland-Morris Disability Questionnaire, Oswestry Low Back Pain Scale, Visual Analog Scale Evaluation and laboratory analysis performed at baseline and at 28 days for assessing the safety and impact on inflammatory markers, which included complete blood counts, C-Reactive protein (CRP), and liver function (alkaline phosphatase, aspartate transaminase, and alanine transaminase). At baseline, there were no statistically significant differences in low back pain when assessed by Roland-Morris function or Oswestry assessments nor were there differences in the blood indices of inflammation. At day 28, both the medical food group and combined therapy group (medical food with naproxen) were statistically significantly superior to the naproxen-alone group (P < 0.05). The medical food and naproxen group showed functional improvement when compared to the naproxen-alone group. The naproxen-alone group showed significant elevations in CRP, alanine transaminase, and aspartate transaminase when compared with the other groups. Medical food alone or with naproxen showed no significant change in liver function tests or CRP, with medical food potentially mitigating the effects seen with naproxen alone. The medical food (Theramine) appeared to be effective in relieving back pain without causing any significant side effects and may provide a safe alternative to presently available therapies.

Entry criteria were a positive exercise treadmill test during placebo therapy characterized by 1.0 mm or more ST segment depression and angina pectoris, and six or more episodes of transient ST segment depression of 1.0 mm or more on a 48-hour ambulatory electrocardiogram. One hundred ninety-four patients were screened, 63 were eligible and received randomized therapy, of which 56 patients completed at least two of the four treatment periods and were included in an intent-to-treat analysis. Fifty patients completed all four treatment phases and were included in the protocol-completed analysis. Anti-ischemia efficacy was assessed by 48-hour ambulatory electrocardiographic monitoring, exercise treadmill tests, and anginal diaries. Ninety-four percent of all episodes of ambulatory ischemia were asymptomatic. Compared with placebo, only propranolol was associated with a marked reduction in all manifestations of asymptomatic ischemia during ambulatory electrocardiographic monitoring (2.3 versus 1.0 episodes/24 hr; mean duration of ischemia per 24 hours, 43.6 versus 5.7 minutes; both p <0.0001). Diltiazem's reduction of the frequency of episodes compared with placebo (2.3 versus 1.9 episodes/24 hr) was associated with a trend (p=0.08) in the protocol-completed analysis and with a significant reduction in the intent-to-treat analysis (p=0.03). Nifedipine had no significant effect on any measured variable of ambulatory ischemia. The dosages of medication used may have been excessive for some patients, and a more beneficial effect may have been evident at a lower dose. In contrast to the marked effects of the active agents on ambulatory asymptomatic ischemia, the effects on exercise performance and angina pectoris were slight. The active agents modestly improved treadmill exercise duration time until 1 mm ST segment depression (3%), and only propranolol and diltiazem had significant effects. Only diltiazem significantly prolonged the total exercise time. Anginal frequency was significantly decreased by both propranolol and diltiazem. We conclude that propranolol is effective for treating episodes of asymptomatic ischemia in patients with stable angina and that the magnitude of improvement in ambulatory asymptomatic ischemia is far greater than the improvement in exercise performance and angina symptoms.