Use of blood-pool imaging in evaluation of diffuse activity patterns in technetium-99m pyrophosphate myocardial scintigraphy.

It has been suggested that diffuse Tc-99m pyrophosphate precordial activity may be due to persistent blood-pool activity in routine delayed views during myocardial imaging. To answer this question, we reviewed myocardial scintigrams recorded 60--90 min following the injection of 12--15 mCi of Tc-99m pyrophosphate for the presence of diffuse precordial activity, and compared these with early images of the blood pool in 265 patients. Diffuse activity in the delayed images was identified in 48 patients: in 20 with acute myocardial infarction and in 28 with no evidence of it. Comparison of these routine delayed images with early views of the blood pool revealed two types of patterns. In patients with acute infarction, 95% had delayed images that were distinguishable from blood pool either because the activity was smaller than the early blood pool, or by the presence of localized activity superimposed on diffuse activity identical to blood pool. In those without infarction, 93% had activity distribution in routine delayed views matching that in the early blood-pool images. The usefulness of the diffuse TcPPi precordial activity in myocardial infarction is improved when early blood-pool imaging is used to exclude persistence of blood-pool activity as its cause. Moreover, it does not require additional amounts of radioactivity nor complex computer processing, a feature that may be of value in the community hospital using the technique to "rule out" infarction 24--72 hr after onset of suggestive symptoms.

Chest pain and bilateral atrioventricular valve prolapse with normal coronary arteries in isolated corrected transposition of the great vessels. Clinical, angiographic and metabolic features.

A man evaluated for disabling chest pain was found to have isolated anatomically corrected transposition of the great vessels. Angiography demonstrated right and left atrioventricular (A-V) valve prolapse and normal coronary arteries. Atrial pacing produced chest pain, ischemic electrocardiographic changes, abnormal myocardial lactate metabolism and marked elevation of the left ventricular end-diastolic pressure; all of these changes returned to normal on termination of pacing. The association of corrected transposition and bilateral A-V valve prolapse and the possible causes of myocardial ischemia in this patient are discussed.

Metabolic consequences of glucose-insulin-potassium infusion in treatment of acute myocardial infarction.

Eighteen patients treated with glucose-insulin-potassium infusion for anaerobic support of acutely ischemic myocardial tissue were studied to ascertain the metabolic consequences of this therapy, for acute myocardial infarction. Twelve patients with acute myocardial infarction were treated in a conventional manner and served as control subjects. The glucose-insulin-potassium solution was composed of 300 g of glucose, 50 units of regular insulin and 80 mEq of potassium ion per liter, and was infused at a rate of 1.5 ml/kg per hour through the right atrial port of an indwelling Swan-Ganz thermodilution catheter. Serial measurements of serum electrolytes, cardiac and hepatic enzymes, glucose and osmolality were obtained every 4 to 6 hours for 4 days. Twenty-four urinary volume and potassium levels were measured daily. Pulmonary arterial end-diastolic pressure was measured hourly and the cardiac index daily for the duration of the study. Serum potassium increased to 5 mEq/liter during the infusion and to more than 6 mEq/liter after infusion in 28 percent of patients. No recognizable complications or arrhythmias accompanied this transient hyperkalemia. Potassium balance studies revealed a net total body potassium ion gain of 120 MEq during the study. The second most frequent finding was an elevation of serum glucose (mean 175 mg/100 ml); in all instances this was controlled with supplemental administration of insulin. The serum osmolality and fluid balance remained normal in all patients during the study. Serum glutamic oxaloacetic transaminase (SGOT) and fraction 5 of lactic dehydrogenase (LDH) were increased in 34 percent of the patients during the last 12 to 18 hours of the glucose-insulin-potassium infusion. Characterization of these enzymes suggested a hepatic origin for these changes. This study suggests that glucose-insulin-potassium infusion is a relatively safe procedure in which postinfusion hyperkalemia is the most serious potential complication.

Isosorbide dinitrate for the relief of severe heart failure after myocardial infarction.

Severe congestive heart failure secondary to myocardial infarction remains a difficult management problem. Although intravenous vasodilators and mechanical assist devices have been reported to improve the depressed hemodynamic function, these interventions are limited to the intensive care unit and cannot be used for long-term management. This study evaluates the hemodynamic and symptomatic response to sublingual administration to isosorbide dinitrate (5 to 10 mg) in seven consecutive patients with severe congestive heart failure after anterior wall myocardial infarction. Serial measurements of mean right atrial and pulmonary arterial end-diastolic pressure, mean blood pressure, heart rate and cardiac output were obtained during the control period and during the 4 hours after administration of isosorbide dinitrate. The peak response occurred approximately 30 minutes after drug administration with an 83 percent reduction in mean right atrial pressure (from 6 to 1 mm Hg, P less than 0.02), a 36 percent reduction in pulmonary arterial end-diastolic pressure (from 25 to 16 mm Hg, P less than 0.0001) and a 6 percent reduction in mean blood pressure (from 94 to 88 mm Hg (P less than 0.05). There were small but statistically not significant increases in cardiac index (from 2.3 to 2.6 liters/min per m2 and stroke work index (from 26 to 32 gm/beat per m2). The total systemic vascular resistance was reduced by 5 percent from 1,605 to 1,518 dynes sec cm-5 (P less than 0.10). The baseline heart rate of 105 beats/min was not significantly changed. The reduction in pulmonary arterial end-diastolic pressure became statistically significant (P less than 0.05) between 15 and 30 minutes after administration of isosorbide dinitrate and remained significant for 3 to 4 hours. This reduction of pulmonary arterial end-diastolic pressure to less than 22 mm Hg was associated with relief of the patients' pulmonary symptoms. The response to nitroglycerin (0.4 mg) was similar in magnitude but of much shorter duration (approximately 15 minutes for nitroglycerin versus 4 hours for isosorbide dinitrate in patients with and without congestive heart failure. The slope (calculated by dividing the change in cardiac index or stroke work index by the change in pulmonary arterial end-diastolic pressure) was significantly (P less than 0.05) depressed in the patients with congestive heart failure. These data demonstrate that the symptomatic pulmonary venous hypertension can be effectively relieved by isosorbide dinitrate without further compromising left ventricular function.

Advantages of the caudocranial left anterior oblique left ventriculogram in adult heart disease.

Biplane axial left cineventriculography represents the most accurate diagnostic technique for evaluating acquired and congenital heart disease. However, data have accumulated to indicate that without angled views of the left ventricle, the diagnosis will be incomplete and inaccurate in a significant number of patients. Left ventriculography is the acknowledged standard for left ventricular performance. However, comparison of the conventional or nonangled left anterior oblique left ventriculogram with the angled views of the left ventricle obtained with either two dimensional ultrasound or radionuclide left ventriculography may in many cases be invalid because dissimilar views are compared. The cranial-left anterior oblique view allows more accurate assessment of the precise degree and extent of asynergy, left ventricular aneurysms and ventricular septal defects. Left ventricular outflow tract abnormalities such as discrete subaortic stenosis and the obstructive form of hypertrophic cardiomyopathy can easily be distinguished. Lesions involving the mitral valve, especially mitral valve prolapse, are readily evaluated. Lastly, comparison with noninvasive tests of left ventricular performance can be more accurately performed.

Advantage of the cranial-right anterior oblique view in diagnosing mid left anterior descending and distal right coronary artery disease.

The value of the cranial-right anterior oblique view in uncovering or improving the arteriographic visualization of lesions in the mid left anterior descending coronary artery, the origin of its diagonal and septal branches and the distal branches of the right coronary artery was analyzed in 300 consecutive patients. The cranial-right anterior oblique view was compared with standard and other angled views. In the mid left anterior descending artery the view provided improved visualization over the other views in 80 percent of cases and uncovered lesions in 7 percent. In the septal arteries, the view improved visualization in more than 90 percent of cases and uncovered lesions in 26 percent. In the diagonal branches, the view improved visualization in nearly 75 percent of cases. In the distal right coronary artery there was improved visualization of the posterior descending and posterolateral branch arteries in more than 80 percent of cases. The cranial-right anterior oblique view was also the most advantageous view from a technical standpoint, yielding satisfactory exposure factors in obese and extremely heavy patients.

Effects of glucose-insulin-potassium on myocardial substrate availability and utilization in stable coronary artery disease. Studies on myocardial carbohydrate, lipid and oxygen arterial-coronary sinus differences in patients with coronary artery disease.

To assess the metabolic effects of myocardial substrate alteration in patients with coronary artery disease, glucose-insulin-potassium solution was administered intravenously for 30 minutes to 14 men with stable angiographically documented coronary artery disease. The glucose-insulin-potassium solution (300 g of glucose, 50 units of regular insulin and 80 mEq of potassium chloride per liter of water) was infused at a constant rate in each patient, but individual infusion rates ranged from 0.013 to 0.032 ml/kg per min (4 to 10 mg glucose/kg per min) in the 14 patients. Simultaneous arterial and coronary sinus samples were obtained at 15 minute intervals during a stable 30 minute control period and again at 15 minute intervals during the infusion; samples were assayed for glucose, lactate, free fatty acid and oxygen content. In all 14 patients, during the glucose-insulin-potassium infusion, arterial glucose and lactate increased and arterial free fatty acid levels fell; the magnitude of the changes in arterial lactate and free fatty acids was related to the rate of infusion. Arterial-coronary sinus differences (A-Cs) for glucose, lactate and free fatty acid levels correlated with the arterial concentrations of these substrates (r = 0.66, 0.87 and 0.79, respectively). Regression analyses demonstrated myocardial thresholds for the uptake of these substrates as follows: glucose 79 mg/100 ml; lactate 300 mu mole/liter; and free fatty acids 100 to 200 mu Eq/liter. Finally and most importantly, the reduction in A-Cs oxygen values after glucose-insulin-potassium infusion correlated with the reduction in A-Cs free fatty acid levels (r = 0.64, P less than 0.0001). This observation suggests that, in patients with coronary artery disease, glucose-insulin-potassium infusion may significantly diminish myocardial oxygen requirements by reduction of myocardial free fatty acid utilization and simultaneous enhancement of myocardial carbohydrate utilization. Myocardial substrate availability may be an important determinant of myocardial oxygen demand in patients with coronary artery disease. Infusion of glucose-insulin-potassium solution has the potential to alter myocardial substrate availability, thus improving the balance between myocardial oxygen demand and supply.

Unstable angina pectoris: a comparison of the costs of medical and surgical treatment.

This study compares the inpatient costs of therapy of patients with unstable angina pectoris randomized to surgical or medical therapy at the University of Alabama in Birmingham as part of the National Cooperative Study Group. For 74 patients followed up for 2 years, the mean inpatient charges were $4,728 for 22 medically treated patients, $9,528 for 34 surgically treated patients and $20,215 for 18 patients who crossed over from medical to surgical therapy. Differences among the three groups were statistically significant (P less than 0.001). Stepwise multiple regression analysis of total inpatient charges with medical and procedural factors as explanatory variables showed that a history of congestive heart failure, the number of infarctions during the period of the study, the duration of the longest anginal attack, the type of unstable angina and the type of treatment were significant predictors of total inpatient cost, with an R2 value of 0.829 (P less than 0.001). These variables explain the cost of treatment. One should not infer that they will also predict the appropriate type of treatment for patients with unstable angina. Although the cost of surgical therapy was double the cost of therapy for patients treated only medically, those medically treated patients whose therapy failed and who subsequently required surgery incurred mean costs twice those of the surgically treated patients and four times of patients who received only medical therapy. Reassessment of previous criticism of the high cost of surgical therapy is indicated.

Modern approach to the patient with acute myocardial infarction.

This presentation has described the modern approach to the patient presenting with chest pain suspected as acute myocardial infarction. Noninvasive and invasive methods have been applied to estimate the extent of the myocardial damage and to monitor the electrical, hemodynamic and metabolic changes during the acute phase. In addition to the use of standard analgesics and antiarrhythmics, measurement of the determinants of left ventricular function by noninvasive and invasive techniques provides a physiologic basis for administration of available pharmacologic agents that can alter the afterload, contractile state, preload, heart rate, metabolic state and infarct size. Information from the Swan-Ganz catheter can describe hemodynamic categories that can be optimally managed by regulation of the left ventricular filling pressure. Patients managed in this manner can be identified for early hospital discharge at 7-10 days. Other patients less than 50 years of age or those experiencing recurrent arrhythmias, ischemic pain or evidence of left ventricular dysfunction may be candidates for coronary arteriography and left ventricular angiography before hospital discharge.

Coronary angiography soon after myocardial infarction.

We evaluated 198 consecutive survivors of acute myocardial infarction and performed selective coronary angiography in 117 of 131 (89 percent) patients who were deemed candidates for angiography by clinical criteria. Overall, left main CAD (greater than or equal to 70 percent stenosis) was found in ten patients (8.5 percent), three vessel CAD in 41 patients (35 percent), two vessel CAD in 37 patients (31.5 percent), single vessel disease in 27 patients (23 percent) and zero vessel disease in two patients (2 percent). Factors suggesting multivessel disease included older age, history of prior myocardial infarction, and post-infarction convalescence complicated by angina pectoris. Factors not discriminating between single and multivessel disease were sex, infarct extent (transmural vs non-transmural), (3) infarct location (anterior vs inferior), and post-infarction convalescence complicated by late arrhythmia or heart failure. This study demonstrates that multivessel coronary artery disease is common in survivors of myocardial infarction and is suggested by the occurrence of post-infarction angina and by the history of an antecedent myocardial infarction. Coronary angiography can be performed safely within 30 days after myocardial infarction in patients with an uncomplicated convalescence and with mild risk in those with a complicated convalescence.

A multipurpose catheter for electrophysiologic and hemodynamic monitoring plus atrial pacing.

A new multipurpose flow-directed pulmonary arterial catheter has been developed and evaluated in 30 patients with acute cardiopulmonary dysfunction. The catheter permits monitoring of the bipolar atrial electrogram, pulmonary arterial or wedge pressure, central venous pressure, and cardiac output, plus atrial pacing. The standard Swan-Ganz thermistor-equipped catheter was modified to incorporate two ring electrodes on the shaft at 25 and 26 cm from the tip. With the pair of electrodes positioned in the right atrium at the junction with the superior vena cava, stable electrograms of high quality were recorded in all 30 subjects, some for as long as six days. These high-fidelity atrial electrograms permitted rapid and accurate diagnosis of many complex dysrhythmias in these unstable patients. Because of the limited noise in the signal of the electrogram, continuous quantitative measurements of intervals by a computerized system was feasible. Furthermore, the stable intracavitary position of electrodes provided a reliable site for atrial pacing, with pacing thresholds (2 to 12 ma; average, 5 ma) that remained stable for up to four days. Atrial pacing was used to treat sinus bradycardia, atrial tachyarrhythmias, digitalis intoxication, and ventricular dysrhythmias.

Cardiac tamponade with nonhemorrhagic pericardial fluid complicating Dressler's syndrome.

A 39-year-old man developed cardiac tamponade with Dressler's syndrome four weeks after an inferior myocardial infarction. Treatment of the tamponade by pericardiocentesis on two occasions produced serous fluid. The pericardial effusion cleared with short-term therapy with corticosteroids and the prolonged use of indomethacin.

Hemodynamic effects of isosorbide dinitrate vs nitroglycerin in patients with unstable angina.

The hemodynamic response to nitroglycerin administration, to sublingual or oral administration of isosorbide dinitrate, or to a placebo was evaluated and compared in 37 patients with unstable angina pectoris under resting, pain-free conditions. Patients with congestive heart failure were not included in this study. Serial measurements of mean arterial blood pressure (MAP), pulmonary arterial end-diastolic pressure (PAEDP), cardiac index (CI), and heart rate (HR) were obtained for one hour following nitroglycerin administration and for four hours following sublingual or oral administration of isosorbide dinitrate. Echocardiographic end-diastolic volume (EDV) measurements were obtained for the groups receiving isosorbide dinitrate or placebo. There was a significant (P less than 0.05 or less than 0.1) reduction of the MAP (5 to 10 mm Hg) that persisted for more than four hours following both sublingual and oral administration of isosorbide dinitrate. The changes in the PAEDP, HR, and CI following sublingual or oral administration of isosorbide dinitrate were small and not significant. In the group receiving isosorbide dinitrate sublingually, the EDV was reduced by more than 30 ml below the placebo group (P less than 0.1) for up to four hours. The effects of nitroglycerin administration were similar in magnitude but of much shorter duration (three to four hours for sublingual and oral administration of isosorbide dinitrate vs 15 to 30 minutes for nitroglycerin). These data demonstrate that the duration of the hemodynamic effects of sublingually and orally administered isosorbide dinitrate in patients with unstable angina pectoris and normal resting hemodynamics is 8 to 12 times longer than that of nitroglycerin.

Deep venous thrombosis of the upper extremity associated with use of the Swan-Ganz catheter.

Two patients who developed unilateral neck vein distention following insertion of a Swan-Ganz catheter are described. One patient developed unilateral swelling of the arm used for catheter insertion. Following removal of the Swan-Ganz catheter in this patient, venograms of both upper extremities revealed internal jugular vein thrombosis and subclavian vein thrombosis of the involved extremity. The other patient had thrombosis of the internal jugular veins and subclavian veins bilaterally, as well as superior vena cava thrombosis.

Glucose-insulin-potassium infusion in acute myocardial infarction. Review of clinical experience.

A solution of 300 gm of glucose, 50 units of regular insulin, and 80 mEq of potassium chloride in 1,000 ml of sterile water infused at a rate of 1.5 ml/kg of body weight per hour can alter the availability of glucose and free fatty acids to the myocardium. Clinical studies of patients receiving this infusion less than 15 hours after the onset of symptoms of acute myocardial infarction suggest a reduction in mortality, an improvement in left ventricular mechanical performance, and a reduction in cardiac irritability as beneficial effects. Swan-Ganz catheterization for hemodynamic, electrophysiologic, and metabolic monitoring is recommended. Diabetics who require insulin and patients with impaired renal function are not candidates for the infusion. Further clinical studies are required before conclusions can be reached regarding the efficacy of glucose-insulin-potassium infusion in attempts to salvage damaged myocardium.

Coronary revascularization surgery: feasibility after myocardial infarction.

Since coronary revascularization improves prognosis in some patients with multivessel disease, can the potential benefits be extended to "prophylaxis" in selected postinfarction patients as well? These investigators sought the answer on the basis of patient characteristics, types of surgery, survival data, and mode of death in the postinfarction population of 129 patients who had early angiography.

Treatment of congestive heart failure.

In treating heart failure, the physician must remain cognizant of pathophysiology as he prescribes and monitors therapy. In addition to seeking underlying and precipitating causes of the patient's heart failure, he must treat the congestive state by enhancing myocardial contractility, controlling excessive fluid retention, and reducing afterload. Figure 7 summarizes the theoretical shifts on a patient's left ventricular function curves that might occur with therapy. Left ventricular function might move from point A to point B with diuretic therapy, but overdiuresis could aggravate symptoms of low cardiac output, including postural hypotension. Digitalis would effect a shift from A to C. Isosorbide dinitrate would produce a shift from A to D in a patient not on digitalis and from C to D in a patient already receiving digitalis. Isosorbide dinitrate, in conjunction with more usual therapeutic measures, has proved clinically beneficial in the treatment of heart failure.