James F. Brymer

Intracoronary fibrinolytic therapy in acute myocardial infarction. Report of a prospective randomized trial.

We performed a randomized trial comparing intracoronary administration of streptokinase versus dextrose placebo within six hours after the onset of symptoms of acute myocardial infarction in 40 patients. The base-line clinical, hemodynamic, and angiographic findings were similar in the control and streptokinase-treated groups. Reestablishment of flow occurred in 12 of 20 patients treated with streptokinase and in 2 of 20 given placebo (P less than 0.05). Left ventricular function, angiographic ejection fraction, and regional wall motion, measured before and immediately after intervention, and serial radionuclide ejection fractions, measured at treatment, at 12 days, and at 5 months, were compared according to type of treatment (streptokinase vs. placebo) and outcome of therapy (reperfusion vs. no reperfusion). No statistically significant differences between groups were found. Thus, although streptokinase was more effective than placebo in achieving reperfusion, we detected no improvement of left ventricular function as a result of reestablished coronary flow.

Coronary Ostial Stenosis A Complication of Aortic Valve Replacement

Eight patients developing coronary ostial stenosis following Starr-Edwards aortic valve placement are reviewed. Coronary perfusion with a balloon tip perfusion catheter was performed during the intraoperative period on all patients and was considered technically satisfactory. Angina pectoris developed within six months of surgery in seven of eight patients and left main coronary artery occlusive disease was demonstrated in each of these cases. One patient who did not develop angina pectoris had right coronary artery narrowing without intraoperative perfusion of this vessel. All patients were reoperated, five survived, two are free of symptoms. Coronary ostial stenosis is a clinically recognizable complication of aortic valve replacement with potential for surgical correction.

A natural history study of the prognostic role of coronary arteriography

Abstract Coronary cinearteriograms, clinical records, and left ventriculograms of 304 patients studied for evaluation of chest pain were reviewed. Clinical and follow-up data on survival of the normal subjects and the nonoperative group with abnormal arteriograms are presented. Ninety-two per cent of patients with typical angina pectoris had serious coronary occlusive disease. Ninety-eight per cent of patients with relatively normal coronary arteriograms survived for one to 60 or more months (mean follow-up period 24 months). There was a high mortality rate when the left main coronary artery was involved (47 per cent) and when the left coronary anterior descending branch was seriously occluded (28 per cent when arteriographic scores were high and 14 per cent when total scores were low) and a low mortality rate (0 to 7 per cent) when the LAD was normal. Mean follow-up interval in these groups was 19 months. The mortality rate was nearly three times greater when patients had QRS changes on ECG of prior myocardial infarction and six times greater when left ventricular contraction was significantly impaired.

Factors Relating to Late Sudden Death in Patients Having Aortic Valve Replacement

The preoperative and postoperative characteristics of a group of 16 patients who died unexpectedly and a control group of 52 late survivors with aortic protheses are reviewed. There were no preoperative differences between the groups for duration of congestive heart failure, electrocardiographic findings, cardiothoracic ratio, or hemodynamic findings. However, on the standard electrocardiogram postoperatively, there were more ventricular arrhythmias in the patients who died suddenly (7 of 16 or 44%) compared with the survivors (5 of 49 or 10%) (p less than 0.05). There were more patients with congestive failure in the study group (10 of 16 or 62%) compared with the controls (4 of 52 or 8%) (p less than 0.05). Patients exhibiting these findings are at risk of sudden death. Arrhythmia monitoring prior to discharge may also be helpful in selecting patients for antiarrhythmia treatment.

Myocardial Revascularization in Patients Receiving Long-Term Propranolol Therapy

Twenty-seven patients receiving long-term propranolol therapy underwent myocardial revascularization to relieve stable or unstable angina. The patients were randomly divided into two groups, one (Group 1) in which propranolol was discontinued 48 hours prior to operation and one (Group 2) in which patients received a final dose of propranolol 1 to 2 hours prior to operation. Several physiological variables were compared, and there was no statistically significant difference between the groups except for a slower pulse rate in Group 2 patients. Although the patients in Group 1 showed a greater frequency of hypertension before bypass, the incidence of postoperative complications and perioperative myocardial infarction was the same for both groups. The findings of this study indicate that myocardial revascularization is safe even if propranolol is administered up to 1 or 2 hours before operation.

Exercise radionuclide ejection fraction: correlation with exercise contrast ventriculography

Thirty-one patients with known or suspected coronary artery disease or aortic valvular disease were studied at rest and during supine bicycle exercise with radionuclide and contrast left ventriculography. The radionuclide ejection fractions calculated independently by three observers correlated well at rest (r = 0.96) and with exercise (r = 0.94). The calculated values also correlated well with those obtained for contrast ventriculography using the area-length method Dodge (r = 0.89 at rest and r = 0.90 with exercise). The results suggest that further clinical applications of exercise radionuclide ventriculography are justified.

The Determination of the Post-Test Likelihood for Coronary Disease Using Bayes Theorem

This report describes a method of using Bayes Theorem for determining the post-test likelihood for coronary disease from the exercise test. The pre-test likelihood is determined from the age, sex, and type of chest pain. Discriminant analysis of the amount of S-T depression, maximum pressure rate product and sex of the patient is then used to determine the sensitivity and specificity of the patients exercise test for coronary artery disease. The post-test likelihood for coronary artery disease can then be calculated using Bayes Theorem. The discriminant function was estimated from a training set of 174 patients. This was then applied to 113 new patients who had both exercise tests and coronary arteriograms. In this new set, 47 patients had a post-test likelihood of 90% or greater for coronary disease. Only one of these patients had normal coronary arteriograms, a predictive accuracy of 98%. Of the 25 patients with a post-test likelihood of 10% or less for coronary disease, four had multivessel disease and four had single vessel disease. The predictive accuracy for the absence of coronary disease was 68%. The predictive accuracy for the exclusion of multivessel disease was 84%. Eight of 10 patients with left main disease had a post-test likelihood for coronary disease of greater than 90%.

The influence of lead strength on the S-T changes with exercise electrocardiography (correlative study with coronary arteriography).

The contribution of relative lead strength to S-T segment depression amplitude during exercise was evaluated in 98 patients who had both a treadmill stress test and a coronary arteriogram. This was accomplished by constructing an exercise S-T depression to R wave ratio (S-T/R) and then relating these ratios to the extent of coronary disease found with arteriography. The additional criterion of 1 mm S-T depression for the bipolar V5 and 0.5 mm for the late unipolar V5 was also reviewed. These criteria were then compared to the sensitivity and specificity of the usual 1 mm S-T depression criterion. The S-T/R ratio of 0.04 improved the detection of significant coronary disease over the usual criteria. The ratio of 0.1 was effective in avoiding false positive tests but lacked sensitivity. This would suggest that strong lead systems may give false positive S-T changes with exercise. The use of 0.5 mm depression as abnormal for the post-exercise unipolar V5 improved sensitivity without loss of specificity over the usual criteria of 1 mm S-T depression criteria. This may be a reflection of the voltage differences between the bipolar lead and the unipolar lead in these two lead systems. It is concluded that lead strength must be considered when evaluating the S-T response to exercise.

Simultaneous treatment of aortic stenosis and coarctation by left thoracotomy with apical aortic conduit.

Abstract The simultaneous treatment of aortic stenosis and coarctation by left thoracotomy with apical aortic conduit is described.

Hemodynamic and myocardial metabolic effects of the β-agonist prenalterol in ischemic left ventricular dysfunction

Hemodynamic and myocardial metabolic parameters in ischemie left ventricular (LV) dysfunction were evaluated in response to the β-agonist prenalterol. Twenty (μg/kg intravenous prenalterol increased resting heart rate and cardiac output and decreased LV filling pressure, systemic vascular resistance, and pulmonary artery pressure. Resting coronary blood flow and myocardial oxygen consumption increased but net myocardial lactate and oxygen extraction did not change significantly. During pacing induced tachycardia (121 ± 4 beats/min), prenalterol improved cardiac index and stroke work index; whereas, LV filling pressure, systemic vascular resistance, and pulmonary artery pressure decreased. Coronary blood flow and myocardial oxygen extraction did not change significantly. Net myocardial lactate extraction during pacing decreased insignificantly; one patient developed overt lactate production. Thus, prenalterol improves cardiovascular function at rest and during pacinginduced tachycardia in ischemie LV failure, but at the cost of higher resting myocardial oxygen consumption. The majority of subjects had no adverse metabolic response.