Risk for systemic embolization of atrial fibrillation without mitral stenosis.

The risk for systemic embolization was studied in 272 patients without mitral stenosis or prosthetic valves who were referred to the echocardiography laboratory with atrial fibrillation (AF). During a mean follow-up period of 33 months (range less than 1 to 83), 27 (10%) patients had a systemic embolic event, which was cerebral in 23 patients (85%) and peripheral in 4 (15%). In the analysis of individual variables, the risk of embolization was increased by female sex, underlying heart disease and left atrial size greater than or equal to 4.0 cm, but not by age, hypertension or type of AF (paroxysmal vs chronic). In multivariable analysis, left atrial size greater than or equal to 4.0 cm was the single strongest predictor of increased risk for embolization (p less than 0.001), but female sex (p = 0.014) and underlying heart disease (p = 0.027) also contributed. When each of these 3 factors was assigned 1 point in a risk score, embolic events were found to occur in none (0%) of 24 patients with a risk score of 0, in 2 (3%) of 83 patients with a risk score of 1, in 13 (11%) of 118 patients with a risk score of 2 and in 12 (26%) of 47 patients with a risk score of 3. The score allows patients with AF and without mitral stenosis to be stratified into high-, medium- and low-risk groups for systemic embolization. Such information could be useful in decision making for anticoagulation in patients with AF.

Regional dysfunction by equilibrium radionuclide angiocardiography: a clinicopathologic study evaluating the relation of degree of dysfunction to the presence and extent of myocardial infarction.

The relation of degree of regional wall motion abnormality by equilibrium radionuclide angiocardiography to the presence and mural extent of regional necrosis or scar at autopsy was evaluated in 23 autopsy patients who had a history of myocardial infarction and had equilibrium radionuclide angiocardiography within 40 days of death. Of the 228 regions evaluated by equilibrium radionuclide angiocardiography, 135 had abnormal regional wall motion and 102 (76%) of these 135 regions had evidence of myocardial infarction at autopsy. The overall sensitivity, specificity and predictive values of regional wall motion abnormality for regional necrosis or scar were 69, 59 and 76%, respectively. Of the 33 false positive regions, 20 (61%) had severe narrowing of the coronary artery supplying that region, 13 (39%) were adjacent to a region with a myocardial infarction and almost half (16 [48%]) were in the lateral wall. Eighty-three (36%) of the 228 regions were akinetic or dyskinetic, 52 (23%) were hypokinetic and 93 (41%) were normal. Sixty-three (76%) of the 83 akinetic/dyskinetic segments had transmural myocardial infarction at autopsy, 14 (17%) had nontransmural myocardial infarction and only 6 (7%) contained no necrosis or scar. In contrast, 14 (27%) of 52 hypokinetic segments had transmural myocardial infarction, 11 (21%) had nontransmural myocardial infarction and 27 (52%) were normal. Thus, the most severe regional wall motion abnormality (akinesia/dyskinesia) almost always indicates regional myocardial infarction which is usually transmural whereas less severe dysfunction (hypokinesia) is not necessarily associated with regional necrosis or scar. The severity of regional dysfunction must be considered if equilibrium radionuclide angiocardiography is used to evaluate the presence and mural extent of myocardial infarction within a region.

Right ventricular myocardial infarction with anterior wall left ventricular infarction: an autopsy study.

Right ventricular myocardial infarction has been reported to occur exclusively in association with inferior left ventricular infarction. To determine the frequency of right ventricular myocardial infarction in association with anterior left ventricular myocardial infarction, all hearts with anterior myocardial infarction studied over a 3-year period were examined for evidence of right ventricular necrosis or scar. Of 97 hearts with anterior myocardial infarction, 13 (13%) had anterior right ventricular myocardial infarction. The right ventricular infarcts involved from 10% to 50% (mean 28%) of the circumference of the right ventricular free wall from base to apex. The associated left ventricular infarcts were all anteroseptal and large and involved from 36% to 67% (mean 50%) of the total area of the left ventricular free wall and septum. Nine of the 13 patients underwent equilibrium radionuclide angiography and six had demonstrable right ventricular regional and global dysfunction. Thus, right ventricular myocardial infarction does occur with anterior wall left ventricular infarction, and right ventricular dysfunction may be demonstrable by radionuclide angiography. Further investigation is needed to define the hemodynamic characteristics, clinical importance, and therapeutic implications of anterior right ventricular myocardial infarction.

Discrimination of normal and atherosclerotic aorta by laser-induced fluorescence.

Precise targeting of laser energy to atherosclerotic plaque is crucial for the safe performance of laser angioplasty. The present study was designed to evaluate whether laser-induced fluorescence could distinguish atherosclerotic from normal aorta. Segments of human aorta obtained at necropsy were classified grossly and histologically as normal aorta (n = 7), thin yellow fatty plaque (n = 5), and thick white atheromatous plaque (n = 9), and analyzed by laser-induced fluorescence spectroscopy using a pulsed nitrogen laser. Fluorescence spectra were recorded over a wavelength range from 385 to 725 nm. Normal specimens had maximal fluorescence intensity at 514 nm. A prominent fluorescence peak at 448 nm was present in specimens characterized as white atheromatous plaque and at 538 nm in specimens characterized as yellow fatty plaque. The ratios of fluorescence intensity at 448 nm/514 nm and at 538 nm/514 nm correctly classified all specimens according to their gross and histologic type (p less than .001). Thus, a "smart" laser angioplasty catheter system might incorporate low-power laser radiation for arterial fluorescence spectroscopy to guide delivery of high-power laser radiation for plaque ablation.

Right-sided infective endocarditis as a consequence of flow-directed pulmonary-artery catheterization. A clinicopathological study of 55 autopsied patients.

We studied 142 consecutively autopsied patients prospectively to determine the frequency and clinical importance of right-sided endocardial lesions in patients who had undergone flow-directed pulmonary-artery catheterization within one month of death. Of the 55 catheterized patients, 29 (53 per cent) had one or more right-sided endocardial lesions: 12 (22 per cent) had subendocardial hemorrhage, 11 (20 per cent) sterile thrombus, 2 (4 per cent) hemorrhage and thrombus, and 4 (7 per cent) infective endocarditis. Of 41 lesions seen in the 29 patients, 23 (56 per cent) were located on the pulmonic valve, 6 (15 per cent) on the tricuspid valve, 6 (15 per cent) in the right atrium, 4 (10 per cent) in the right ventricle, and 2 (5 per cent) in the main pulmonary artery. All four patients with infective endocarditis had had positive antemortem blood cultures while the catheter was in place, but in only one had the diagnosis of endocarditis been suspected clinically. The unusual locations of the infected vegetations (on the pulmonic valve in three and in the right atrium in one) and the similar location of the uninfected lesions suggest that the infective endocarditis was a consequence of catheter-induced endocardial damage with concurrent or subsequent bacteremia. Among the 87 non-catheterized patients, there were two subendocardial hemorrhages and one resolving right atrial thrombus. We conclude that endocardial damage from flow-directed pulmonary-artery catheterization is common and that right-sided infective endocarditis should be suspected in bacteremic catheterized patients.