Albert S. Most

Evaluation of the role of coronary angioplasty in patients with unstable angina pectoris

Seventeen patients presenting with unstable angina pectoris underwent percutaneous transluminal coronary angioplasty (PTCA). Despite vigorous medical therapy, all patients were disabled with 10 experiencing refractory in-hospital angina. PTCA was judged successful in 13 patients and resulted in decreased coronary diameter narrowing from 80 +/- 16% to 34 +/- 13% and reduced transstenotic pressure gradient from 69 +/- 13 to 23 +/- 12 mm Hg. Regional coronary blood flow (CBF) and myocardial metabolism were assessed at rest and during pacing tachycardia in six patients with left anterior descending coronary stenosis. Prior to PTCA, neither regional CBF increased nor coronary vascular resistance declined during rapid pacing; myocardial lactate extraction fell, indicating a shift from aerobic to anerobic metabolism. Following PTCA, however, rapid pacing resulted in increased regional CBF, decreased coronary vascular resistance, and preservation of aerobic metabolism. Following PTCA, successfully dilated patients demonstrated marked relief of angina symptoms, increase in functional capacity, and objective exercise ECG and thallium scintigraphic evidence of relief of previously ischemic myocardium. This investigation demonstrates that PTCA, when combined with medical therapy, can be performed safely and successfully in selected patients who present with otherwise refractory unstable angina, and indicates the procedure deserves further study as a therapeutic alternative in this condition.

Thrombolytic therapy for prosthetic cardiac valve thrombosis

To determine the efficacy and safety of thrombolytic therapy for prosthetic valve thrombosis, a composite series of 41 patients who received either streptokinase or urokinase intravenously for this disorder were analyzed. The series comprised 3 patients treated at Rhode Island Hospital and 38 previously reported on. Short-term success was achieved in 32 patients (78%). Prosthetic valve thrombosis recurred in seven (22%) of the successfully treated patients, four of whom were retreated with thrombolytic therapy. A favorable clinical outcome was observed in each. Fever and venipuncture bleeding were the most frequent side effects. Systemic embolization occurred in 4 (15%) of 26 patients with either aortic or mitral prosthetic valve thrombosis. None of these latter patients experienced a permanent neurologic or circulatory deficit. It is concluded that thrombolytic therapy is of value in the treatment of prosthetic valve thrombosis.

Free fatty acid metabolism of the human heart at rest

Myocardial substrate metabolism was studied in 13 subjects at the time of diagnostic cardiac catheterization by means of palmitic acid-(14)C infusion with arterial and coronary sinus sampling. Two subjects were considered free of cardiac pathology and all, with one exception, demonstrated lactate extraction across the portion of heart under study. Data for this single lactate-producing subject were treated separately.The fractional extraction of (14)C-labeled free fatty acids (FFA) (44.4+/-9.5%) was nearly twice that of unlabeled FFA (23.2+/-7.8%) and raised the possibility of release of FFA into the coronary sinus. FFA uptake, based on either the arterial minus coronary sinus concentration difference or the FFA-(14)C fractional extraction, was directly proportional to the arterial FFA concentration. Gas-liquid chromatography failed to demonstrate selective handling of any individual FFA by the heart. Fractional oxidation of FFA was 53.5+/-12.7%, accounting for 53.2+/-14.4% of the hearts oxygen consumption while nonlipid substrates accounted for an additional 30.0+/-17.3%. Determinations of both labeled and unlabeled triglycerides suggested utilization of this substrate by the fasting human heart. Direct measurement of FFA fractional oxidation as well as FFA uptake, exclusive of possible simultaneous FFA release, would appear necessary in studies concerned with human myocardial FFA metabolism.

Myocardial hemorrhage after coronary reperfusion in pigs

Abstract The effects of 1 hour of occlusion of the left anterior descending coronary artery and subsequent reperfusion were studied for 3 hours in anesthetized closed chest pigs using an intracoronary balloon occluding technique. In 12 pigs subjected to reperfusion, S-T segment elevation decreased to control levels within 30 minutes and was significantly less than in 10 control pigs without reperfusion ( P P This study thus documents the occurrence of postreperfusion myocardial hemorrhage in an animal with a coronary circulation similar to mans. Hemorrhage is directly related to the duration of occlusion but appears to be unaffected by mannitol given before reperfusion. Caution is advised both during bypass surgery, in which occlusion and reperfusion occur, and In efforts to restore coronary blood flow during acute myocardial infarction.

Postexercise Electrocardiography in Patients with Arteriographically Documented Coronary Artery Disease

Abstract The relationship between coronary cinearteriographic findings and postexercise electrocardiographic (ECG) evidence of ischemia was examined in 65 persons with angina pectoris and documente...

Arrhythmia surveillace by transtelephonic monitoring: Comparison with Holter monitoring in symptomatic ambulatory patients

Abstract We have evaluated a patient-actuated transtelephonic monitoring system (TTM) in order to determine its ability to document the cardiac rhythm at the time of symptoms; results have been compared to a simultaneously recorded 24-hour Holter Monitor (HM). Forty patients submitted an average of 15.6 TTM recordings/patient over a 7-day recording period. Twenty-six patients reported significant symptoms during the period of study: 11 had demonstrated arrhythmias, and these were documented by HM alone in one, by TTM alone in four, and by both HM and TTM in six. In 15 patients, no arrhythmia was seen during symptoms. HM alone was useful in excluding arrhythmia as a cause for the symptoms in two patients, TTM alone in six patients, and both in the remaining seven patients. Cumulative diagnostic usefulness in evaluating the significance of symptoms potentially attributable to arrhythmia is summarized: HM alone useful in three patients, TTM alone useful in 10 patients, and both HM and TTM useful in 13; TTM was significantly more useful than HM ( χ 2 = 3.69; P Of note is that six patients had significant arrhythmias during asymptomatic periods, including VPCs (four), severe sinus bradycardia (one), and rapid atrial fibrillation (one). In these few patients, both techniques appeared equally able to document asymptomatic arrhythmias. These observations demonstrate that TTM carried out over a 7-day period is superior to a 24-hour Holter monitor recording in its ability to establish the significance of symptoms potentially attributable to arrhythmia, and appeared equally sensitive to HM in demonstrating periods of asymptomatic arrhythmia. TTM can therefore be considered a simple, accurate, and useful technique for arrhythmia surveillance in the symptomatic patient.

Role of myocardial ischemia in the genesis of stress-induced S-T segment elevation in previous anterior myocardial infarction

This study tests the hypothesis that myocardial ischemia is responsible for exercise-induced S-T segment elevation in patients with previous anterior myocardial infarction (MI). Exercise stress testing in conjunction with thallium imaging of the myocardium was performed in 28 patients with previously documented anterior MI. Thallium images were analyzed by computer for the presence of initial uptake defects and evidence of abnormal clearance of the isotope from the myocardium (that is, imaging evidence of ischemia). Total S-T segment elevation (sigma ST) in precordial leads V1 to V6 at rest was subtracted from sigma ST at peak stress in order to quantitate the extent of S-T elevation induced by stress (delta ST). Two groups of patients were identified; 1 with stress-induced S-T elevation (Group I, delta ST greater than or equal to 4.0 mm) and 1 without this abnormality (Group II, delta ST less than 4.0 mm). Evidence of abnormal thallium washout from myocardial scan segments occurred in 12 of 15 Group I patients versus 9 of 13 Group II patients (difference not significant). In addition, abnormal tracer washout from anterolateral or septal scan segments occurred in 5 patients in each group. Likewise, abnormal thallium clearance from inferior or posterior scan segments occurred in 8 of 15 Group I patients versus 7 of 13 Group II patients (difference not significant). The patient with the greatest amount of stress-induced S-T elevation (S-T 11.5 mm) had no evidence of ischemia during the stress test. However, Group I patients did have larger anterolateral plus septal initial thallium uptake defect scores than did those of Group II (10 of 15 with defect score greater than or equal to 350 in Group I versus 1 of 13 in Group II, p less than 0.002). Similarly, resting left ventricular ejection fraction greater than or equal to 30% was present in only 4 of 15 Group I patients versus 13 of 13 in Group II (p less than 0.001). Finally, multiple stepwise linear regression analysis demonstrated that delta ST correlated best with the extent of initial anterolateral plus septal thallium uptake defect score (F = 17.3, p less than 0.001) and to a lesser extent with resting ejection fraction (F = 5.2, p less than 0.05) and change in heart rate from rest to peak stress (F = 8.1, p less than 0.01; corrected multiple correlation coefficient = 0.76, p less than 0.001). Thus, in patients with previous anterior MI (1) exercise-induced myocardial ischemia occurs as often with as without S-T segment elevation, (2) myocardial ischemia is not required for the production of stress-induced S-T segment elevation, and (3) stress-induced S-T elevation primarily reflects the extent of previous anterior wall damage and to a lesser extent an increase in heart rate between rest and peak stress.

Complete heart block as a cause of syncope in asymmetric septal hypertrophy

This case report presents a young adult with asymmetric septal hypertrophy (ASH) and syncope. Infranodal complete heart block was demonstrated as his cause for syncope. Therapy consisted of implantation of a A-V sequential pacemaker. Cardiac output determinations and systolic time intervals demonstrated the beneficial effects of properly timed atrial contractions.

Glucose Extraction by the Human Myocardium during Pacing Stress

Glucose extraction by ischemic human myocardium was investigated at the time of diagnostic cardiac catheterization in 27 subjects who had fasted overnight. Paired arterial and coronary sinus blood samples, obtained before and during coronary sinus pacing, were analyzed for glucose and lactate. Pacing to a rate 50 to 70% greater than control or to the development of chest pain induced no significant change in the arterial level of either substrate. No correlation was noted between arterial level and myocardial extraction of either substrate at rest or during stress.Three groups of subjects were identified: group I: those with lactate extraction at rest and during pacing (n = 13); group II: those with lactate extraction at rest but production during pacing (n = 7); and group III: those with lactate production at rest with augmented production during pacing (n = 5). Two additional subjects produced lactate at rest but were not paced. Glucose extraction increased significantly with pacing tachycardia in group II (0.09 ± 0.03 mM to 0.26 ± 0.04 mM) and in group III (0.38 ± 0.17 mM to 0.58 ± 0.12 mM). No significant increase was noted in group I. A significant correlation was noted between glucose extraction and lactate production during pacing when groups II and III were combined (r = 0.81; P < 0.001).Myocardial ischemia in man was associated with augmented glucose extraction. The arterial glucose concentration was not a primary determinant of glucose extraction either before or during induced ischemia.

Coronary angioplasty for patients with multivessel coronary artery disease: Follow-up clinical status

To determine the value of percutaneous transluminal coronary angioplasty (PTCA) for patients with multivessel coronary artery disease, we reviewed follow-up data of 92 consecutive multivessel disease patients in whom PCTA had been successful and in whom at least 6 months had elapsed. Clinical outcome of multivessel disease patients was compared to that of 189 patients with single-vessel disease who experienced successful PTCA. Eighty percent of multivessel disease patients noted clinical improvement at follow-up. More single-vessel disease patients, however, were free of angina (77% vs 63%, p = 0.02), were not taking long-acting antianginal medicationS (46% vs 27%, p less than 0.001), and had repeat PTCA less often (5% vs 12%, p = 0.05) than multivessel disease patients. The incidence of late clinical events such as myocardial infarction, coronary artery bypass surgery, and death was low in both single- and multivessel disease patients. To determine whether the degree of revascularization achieved accounted for differences between single- and multivessel disease outcome, PTCA for multivessel disease was classified as either complete or incomplete revascularization. Those patients classified as having incomplete revascularization, although they had multivessel coronary artery disease, had only one significant ischemic zone and this was successfully revascularized by PTCA. There was no significant difference in anginal status or incidence of myocardial infarction, coronary artery bypass surgery, or death between the two multivessel disease subgroups. Thus, PTCA is of clinical value for selected patients with multivessel coronary artery disease, even in those who are incompletely revascularized by design.