Effect of furosemide on hemodynamics and lung water in acute pulmonary edema secondary to myocardial infarction

Hemodynamic studies were carried out in 19 patients with left ventricular failure complicating acute myocardial infarction. Fourteen patients were studied before and after the intravenous administration of 0.5 mg/kg of furosemide, and five patients served as a control group. Serial measurements included intracardiac pressures, cardiac output and lung water by a double isotope technique. A significant reduction was noted in right atrial (P < 0.005), pulmonary arterial (P < 0.0005) and pulmonary wedge pressures (P < 0.0005) after administration of furosemide. Only the change in right atrial pressure was significantly different from that in the control group (P < 0.05). Lung water was not changed in 4 patients studied 2 hours after administration of furosemide but was significantly changed in the remaining 10 patients studied 4 to 24 hours after furosemide (P = 0.0001). This change was also significantly different from values in the control group (P < 0.05). The patients with no reduction in excess lung water also had a smaller reduction in pulmonary wedge pressure and a lower pretreatment stroke work index than the other patients.The mobilization of excess lung water in patients with acute myocardial infarction complicated by left ventricular failure has several features. Despite a prompt diuresis, the reduction in lung water is delayed for at least several hours after the administration of furosemide and may be related to the degree of left ventricular dysfunction. Venodilation may be a major result of treatment with furosemide.     

Nifedipine in chronic stable angina: a double-blind placebo-controlled crossover trial

Thirty patients with chronic stable angina pectoris were randomized in a double-blind prospective placebo-controlled crossover trial to assess the efficacy of nifedipine (30 to 60 mg/day orally) in controlling symptoms and objective signs of myocardial ischemia using a symptom-limited treadmill exercise test. Adverse effects that occurred during both nifedipine and placebo treatment were minor and generally well tolerated. Twenty-three patients were analyzed from the crossover phase of the study. Nifedipine significantly reduced the frequency of angina by 55% and nitroglycerin consumption by 59%, and increased exercise time by 34%. These changes were significantly greater than those in the placebo group. Hemodynamic evaluation during exercise revealed a significant reduction in systolic and diastolic blood pressures in the nifedipine group at the onset of angina and at maximal exercise without significant differences in heart rate responses in the nifedipine and placebo groups. The pressure-rate product during submaximal exercise was significantly smaller in the nifedipine group than in the placebo group, but did not differ significantly in the 2 groups at the onset of angina or on maximal exercise. Furthermore, S-T segment depressions that occurred during exercise at the same pressure-rate products were smaller in the nifedipine period than in the placebo period. Thus, it appears that the antianginal effects of nifedipine are caused by a reduced myocardial oxygen demand for a specific work load and possibly by an increased blood supply to ischemic myocardium.     

Two dimensional echocardiographic evaluation of exercise-induced left and right ventricular asynergy: Correlation with thallium scanning

Adequate real time two dimensional echocardiograms were prospectively obtained before and immediately after graded treadmill exercise testing in 41 of 48 patients who underwent cardiac catheterization for suspected coronary artery disease. Findings were correlated with thallium perfusion scans performed 5 to 10 minutes and 3 hours after the same exercise test. Exercise-induced wall motion abnormalities were detected in 19 of 23 patients with significant coronary artery disease and no prior myocardial infarction as well as in all 5 patients with known previous infarction. Three patients with coronary artery disease experienced new isolated right ventricular asynergy with exercise that would have been missed if only the left ventricle had been evaluated. Exercise-induced thallium perfusion defects showed good correlation with exercise-induced asynergy as detected with echocardiography. Two dimensional echocardiography performed immediately after treadmill stress testing is a feasible and rewarding technique in the evaluation of patients suspected to have coronary artery disease.     

Obstruction within the right ventricular body: two-dimensional echocardiographic features

Real-time 2-dimensional (2-D) echocardiograms were performed in 4 patients, all with considerable obstruction within the right ventricular (RV) body, in 3 patients due to muscle bundles and in 1 due to hypertrophic cardiomyopathy (HC). None had obstruction at the pulmonic valve level or immediately below. Echocardiographically, obstruction presented in 3 patients as localized bulging of the RV free wall in the subinfundibular region such that the RV cavity presented a typical "hourglass" appearance. Associated ventricular septal defect (VSD) was detected in 2 patients by echocardiography. In the fourth case, a patient with HC, RV obstruction was associated with a prominent bulge of the ventricular septum into the right ventricle. In 3 patients, the obstruction was convincingly demonstrated only in the subcostal RV inflow-apex-outflow plane, rather than in the standard echocardiographic planes. Pulse Doppler studies in 2 patients demonstrated disturbed RV flow. Obstruction within the RV body is a potentially serious condition which has been overlooked both at cardiac catheterization and at surgery. Demonstration of this lesion by 2-D echocardiography appears feasible and would greatly improve diagnostic accuracy.     

Two-dimensional and Doppler echocardiographic evaluation of aortic aneurysm and dissection

Ten patients with nondissecting aortic aneurysm and 10 with aortic dissection proved by angiography, surgery or both, were studied by real-time, 2-dimensional echocardiography. Multiple transducer positions were used to visualize various aortic segments so that a composite image of the aorta could be formulated. Using this comprehensive approach, the site, size and extent of all nondissecting aneurysms were correctly delineated (2 ascending aorta, 3 ascending aorta plus aortic root and 5 aortic arch with brachiocephalic involvement). In all patients with aortic dissection, the condition was identified by the presence of prominent, flap-like, undulating motion of the inner dissected wall or marked parallel wall widening (greater than or equal to 15 mm) and correctly categorized into DeBakey type I (4 cases), II (2 cases) or III (4 cases). Pulsed Doppler studies were useful in diagnosing reopening of dissection in a patient with previous surgical obliteration of the false channel.     

Two-dimensional echocardiographic identification of pulmonary artery branch stenosis

Pulmonary artery branch stenosis is a not uncommon congenital lesion, noted in approximately 4% of children at the time of cardiac catheterization. Real-time 2-dimensional echocardiography was used to examine 10 patients with angiographically documented pulmonary branch stenosis. Five cases of pulmonary artery branch narrowing were identified by echocardiography without prior knowledge of angiographic findings. In 5 other patients whose angiographic results were known, the narrowings were identified in 4 of 5 cases. These results demonstrate the feasibility of evaluating pulmonary branch stenosis with the nonionizing, noninvasive method of 2-dimensional echocardiography.     

Ejection fraction determination without planimetry by two-dimensional echocardiography: a new method

A new method for determining ejection fraction by two-dimensional echocardiography was assessed in 60 patients undergoing angiography. In method A, the left ventricular minor axis was measured at the midventricular cavity level in end-systole and end-diastole using the apical four chamber view in the 60 patients. The left ventricular major axis was also measured from the left ventricular apex to the base of the mitral valve at end-systole and end-diastole. The ejection fraction was determined using a modified cylinder-ellipse algorithm. In method B, measurements of the left ventricular minor axis were made in 40 consecutive patients, at the upper, middle and lower thirds of the left ventricular cavity at end-systole and end-diastole of the same cardiac cycle and left ventricular major axis was measured as in method A. With use of the same algorithm, three regional ejection fractions were determined and averaged to yield the total ejection fraction. The two echocardiographic methods were compared with single plane cineangiography in all patients and with gated nuclear scanning in 14 patients. Reproducibility was assessed by interobserver comparison. Correlation was determined in all patients and then separately for those with echocardiographic wall motion abnormalities. The correlation coefficient for all patients was 0.79 (probability [p] less than 0.001) for method A and 0.90 (p less than 0.001) for method B. For patients with wall motion abnormalities, method A had a correlation coefficient of 0.38 (p less than 0.1) and method B showed much higher correlation with r = 0.82 (p less than 0.001). Corresponding values for methods A and B in patients without wall motion abnormality were 0.85 (p less than 0.001) and 0.88 (p less than 0.001), respectively. Unlike a previous study, this method directly measures fractional shortening of left ventricular major axis and ejection fraction values are not arbitrarily modified by type of wall motion abnormality. With this method, accurate measurement of ejection fraction can be made by two-dimensional echocardiography without planimetry. In the absence of echocardiographic wall motion abnormalities, a very simple method A suffices. If wall motion abnormalities are present, the regional ejection fraction method B provides excellent results.     

Differentiation of left ventricular pseudoaneurysm from true aneurysm with two dimensional echocardiography

Real time two dimensional echocardiographic findings in four patients with a pathologically proved left ventricular pseudoaneurysm were compared with those in seven patients with a similarly proved true aneurysm of the left ventricle. Pseudoaneurysms produced a bounded echo-free space with a narrow neck that communicated with the left ventricular cavity. The maximal internal width of this neck (O_max) was much smaller than the maximal parallel internal diameter (D_max) of the aneurysmal sac, and the ratio O_max/D_max never exceeded 0.5. In all cases the pseudoaneurysm could be seen extending behind the intact portion of the involved left ventricular wall, and this finding produced a characteristic beak-like configuration in the studies of two patients. In contrast, true aneurysm resulted in local bulging and dilatation of the left ventricular wall so that the maximal internal width of the mouth (O_max) was nearly equal to, or actually represented, the maximal internal diameter (D_max) of the aneurysm so that the ratio O_max/D_max ranged from 0.9 to 1.0. Our preliminary study indicates that real time two dimensional echocardiography is useful in differentiating pseudoaneurysm from true aneurysm of the left ventricle.     

Ventricular arrhythmias and cardiac hemodynamics in patients with myocardial infarction. Comparison of the acute and post-hospitalization phases

Sixty-six patients with myocardial infarction (MI) were studied during the acute hospital phase and during the six months after hospital discharge. The clinical characteristics, location of infarction, and data from right heart catheterization were studied in an attempt to determine what factors were associated with ventricular rhythm disturbance.Those patients with serious ventricular arrhythmias (SVA) in the acute phase of infarction were found to have a significantly greater degree of myocardial dysfunction as measured by pulmonary artery and pulmonary wedge pressure than patients with more normal rhythm (p<.05). Clinical classification of patients and location of infarction were not helpful in predicting SVA during the acute infarction period.Knowledge of hemodynamic data, presence of SVA and clinical characteristics in the acute infarction period were of no value in predicting the occurrence of SVA after hospital discharge. Patients having had an acute diaphragmatic infarction were found to have a higher incidence of SVA after hospital discharge.     

Postextrasystolic Potentiation as a Predictor of Potential Myocardial Viability: Preoperative Analyses Compared With Studies After Coronary Bypass Surgery

The ability to predict reversibility of ventricular dysfunction should be important in determining operability. This study examined the usefulness of postextrasystolic potentiation as such a predictor. Left ventricular wall motion was studied using cineventriculography in 31 patients before and after revascularization surgery. Preoperative ejection fraction and wall motion were analyzed during a sinus beat and after a random ventricular extrasystole, whereas postoperative ejection fraction and wall motion were examined only during a sinus beat. Changes in ventricular motion were correlated with changes in vascular supply achieved by operation. Of the 7 patients whose ejection fraction was improved postoperatively, 6 had shown postextrasystolic potentiation compared with only 10 of the 24 patients without such improvement (P less than 0.05). Regional wall motion analysis also showed a significant association between postextrasystolic potentiation and postoperative improvement in wall motion. Of 26 zones judged to have an increased vascular supply after operation, 11 showed increased motion postoperatively. All 11 had shown postextrasystolic potentiation, compared with only 5 of 15 zones with increased vascular supply but without increased postoperative motion (P less than 0.001). Thus, postextrasystolic potentiation seems to be a useful predictor of the ability of asynergic myocardium to respond to successful revascularization surgery.     

Age and prior caffeine use alter the cardiovascular and adrenomedullary responses to oral caffeine

The effects of age and chronic caffeine use (approximately 300 mg/day) on the cardiovascular and humoral responses to 250 mg of oral caffeine (the equivalent of 2 to 3 cups of coffee) were examined. Older subjects had greater increases in blood pressure than younger subjects (p less than 0.03), and caffeine nonusers had greater blood pressure increases than caffeine users, regardless of age (p less than 0.05). Caffeine increased the product of systolic blood pressure and heart rate (an estimate of myocardial oxygen demand) in older caffeine nonusers, but this effect was absent in older caffeine users (p less than 0.01). Cardiovascular effects of caffeine could not be related temporally to changes in plasma epinephrine, which were greater in caffeine nonusers and younger subjects, or to plasma norepinephrine, renin activity or vasopressin, which did not change. Thus, age accentuates and moderate prior caffeine use attenuates the cardiovascular effects of oral caffeine; these effects are not mediated solely through the sympathoadrenal system.     

Noninvasive diagnosis of mitral prosthesis malfunction

We describe the utilization of echocardiography and phonocardiography in the diagnosis of malfunction of the Smeloff-Cutter mitral prosthesis in a patient in whom corrective surgery was subsequently performed without the necessity of cardiac catheterization studies. The noninvasive studies also delineated prosthesis malfunction as the etiology of pulsus alternans, noted clinically in this patient.     

Automatic real time arrhythmia monitoring in the intensive coronary care unit.

A prospective study was carried out to evaluate accuracy of a real time computer system for arrhythmia monitoring in a coronary care unit. QRS complexes in 57 continuously recorded 30 minute electrocardiographic rhythm strips from 30 patients were classified by the computer. Blinded interpretation of each beat was made by a cardiologist. A total of 146,638 QRS complexes were classified during the monitoring period of 1,710 minutes. The accuracy rate of computer detection was 99.94%. During this period 67 artifacts were identified as beats. The computer correctly identified 5,467 of 5,729 ventricular premature beats (accuracy of detection rate 95.46%). The incidence rate of false positive diagnosis of beats other than ventricular ectopic beats was 0.1%. The rate of computer accuracy in detecting ventricular premature beats was 93.33% in two patients with atrial fibrillation. In individual patients, computer interpretation did not deviate from the cardiologist's interpretation by more than 1 beat/min. The rate of computer accuracy in detecting supraventricular premature beats was lower (82.45%). The distinctly improved accuracy of computer monitoring of ventricular arrhythmia in a coronary care unit reported is the result of a new algorithm. This approach combines major elements of cross correlation of QRS signals as well as grouping of complexes into families. Normal and abnormal templates are stored and newly detected QRS complexes are matched. The program appears to be sufficiently accurate to warrant further applications.     

Myocardial texture characterization by two-dimensional echocardiography

Twenty-four normal subjects and 181 patients with various cardiac disorders (36 autopsies) were studied by 2-dimensional echocardiography. In vitro echocardiographic studies were performed on 26 of 36 autopsied hearts utilizing an ultrasonically visible metallic probe to correlate myocardial echo patterns with histopathologic features. All normal subjects and the majority of patients with ventricular hypertrophy due to valvular or hypertensive lesions showed a uniformly speckled or an echolucent appearance of the myocardium (type I texture). No autopsied heart with this texture had gross fibrosis (visible to the naked eye) or infiltrative disease. All patients with infiltrative disorders (amyloidosis, 7 of 7; Pompe's disease, 4 of 4) had multiple, discrete, and small (3 to 5 mm) highly refractile echoes (HREs) in the myocardium involving the ventricle or ventricles completely (type IIA texture) or partly (type IIB texture). However, this finding was non-specific and was observed in many other conditions such as left heart hypoplastic syndrome (10 of 10), hypertrophic cardiomyopathy (19 of 26), and chronic renal failure (4 of 9). In the noninfiltrative group, HREs in the autopsied cases were shown to result from gross fibrosis or endocardiofibroelastosis utilizing in vitro echocardiographic studies and metallic probe-guided biopsies, while HREs in the autopsied cases with cardiac amyloidosis could be correlated only with amyloid deposits since fibrosis was absent. Larger HREs (greater than 5 mm) presenting as broad patches or long linear echoes in the myocardium (type IIC texture) was seen in old myocardial infarctions (9 of 21) and congestive cardiomyopathy (4 of 26) and were correlated with large areas of myocardial fibrosis. Two-dimensional echocardiographic studies of myocardial texture help identify various infiltrative and degenerative processes in the heart.     

Thrombolytic therapy for acute transmural myocardial infarction. Intracoronary versus intravenous

The application of coronary angiography in coordination with streptokinase administration directly into the occluded coronary artery has served to focus attention on the clinical potential of such therapy. About 75 percent of patients with acute transmural myocardial infarction have been shown to have reperfusion after intracoronary administration of streptokinase. However, the data do not prove that the beneficial effect required regional perfusion. Analysis of biochemical data suggests that the active agent was not confined to the locale of the thrombus, but in fact circulated in significant concentration; furthermore, systemic (intravenous) treatment resulted in reperfusion of a significant proportion (50 percent) of coronary arteries as well. Comparative studies are needed to critically compare angiographic results after regional or systemic therapy and also to assess the impact of reperfusion on possible reduction in long-term morbidity and mortality. Although intracoronary therapy appears to be more effective for inducing reperfusion, intravenous therapy has the potential for greater clinical impact, since it can be instituted more quickly after the onset of symptoms and does not require specialized cardiac catheterization facilities.