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Biomedical subjects

M H Crawford

Publications and source records attributed to M H Crawford.

At least 19 recordsLinked to original sources
PubMed1992

Systemic lupus erythematosus valve disease by transesophageal echocardiography and the role of antiphospholipid antibodies.

OBJECTIVES: The aims of this study were to better characterize valve disease in systemic lupus erythematosus and to determine its association with antiphospholipid antibodies. BACKGROUND: Estimates of the prevalence of valve disease in systemic lupus erythematosus have been higher in autopsy series than in clinical studies using transthoracic echocardiography. Antiphospholipid antibodies have been suggested to be a primary pathogenetic factor. METHODS: Transesophageal echocardiography was performed on 1) 54 patients with lupus erythematosus, 22 of them with (group I) and 32 without (group II) antiphospholipid antibody; 2) on 10 patients with antiphospholipid syndrome (group III); and 3) on 35 normal subjects (group IV). RESULTS: Patients in groups I and III had similar types and concentrations of antibodies. Leaflet thickening was found in 50% of group I, 47% of group II, 10% of group III and 9% of group IV patients (group I or II vs. group III or IV, p < 0.03). Leaflet thickening in patients with lupus erythematosus was diffuse; it usually involved the mitral and aortic valves and was associated with valve regurgitation (73%) or valve masses (50%). Valve masses were observed in 41% of group I, 25% of group II, 10% of group III and in none of group IV patients (group I or II vs. group IV, p < 0.002). Most valve masses in patients with lupus erythematosus were located near the base on the atrial side of the mitral valve or on the vessel side of the aortic valve, had variable size (0.2 to 0.85 cm2), shape and echodensity. Valve regurgitation was observed in 64% of group I, 59% of group II, 10% of group III and 20% of group IV patients (group I or II vs. group III or IV, p < 0.006). Moderate or severe regurgitant lesions were noted in 27% of group I and 25% of group II patients. CONCLUSIONS: Lupus erythematosus valve disease is frequent (74%) regardless of the presence or absence of antiphospholipid antibodies. Therefore antiphospholipid antibodies may not be a primary pathogenetic factor. The characteristic appearance of leaflet thickening and masses in patients with lupus erythematosus may be unique.

Adult↗
PubMed1992

Digital dermatoglyphic patterns of Eskimo and Amerindian populations: relationships between geographic, dermatoglyphic, genetic, and linguistic distances.

Dermatoglyphic traits have been used to assess population affinities and structure. Here, we describe the digital patterns of four Eskimo populations from Alaska: two Yupik-speaking villages from St. Lawrence Island and two Inupik groups presently residing on mainland Alaska. For a broader evolutionary perspective, these four Eskimo populations are compared to other Inuit groups, to North American Indian populations, and to Siberian aggregates. The genetic structures of 18 New and Old World populations were explored using R-matrix plots and Wright's FST values. The relationships between dermatoglyphic, blood genetic, geographic, and linguistic distances were assessed by comparing matrices through Mantel correlations and through partial and multiple correlations. Statistically significant relationships between dermatoglyphics and genetics, genetics and geography, and geography and language were revealed. In addition, significant correlations between dermatoglyphics and geography, with linguistic variation constant, were noted for females but not for males. These results attest to the usefulness of dermatoglyphics in resolving various evolutionary questions concerning normal human variation.

Alaska↗
PubMed1979

Beneficial effects of prolonged low dose dopamine in hospitalized patients with severe refractory heart failure.

In 10 hospitalized patients with severe congestive heart failure refractory to standard medical therapy for three days, low dose intravenous dopamine (2-4 micrograms/kg/min) was infused for 48 h. Heart rate and systolic blood pressure were unchanged throughout the study. Mean pulmonary artery wedge pressure decreased significantly during the dopamine infusion from 27 +/- 6 (SD) to 18 +/- 6 mmHg (p less than 0.01) and cardiac output increased from 3.2 +/- 1.1 to 4.6 +/- 0.8 l/min (p less than 0.001). A diuresis was initiated in all patients and there was a significant weight loss during the study which averaged 5 lbs (p less than 0.01). All patients improved symptomatically from class IV (NYHA) to class III and were more responsive to conventional therapy after the study. No adverse reactions were noted in this dose range. We conclude that low dose intravenous dopamine is efficacious in improving hemodynamics and initiating a diuresis in patients with severe refractory congestive heart failure.

Adult↗
PubMed1979

Upright exercise echocardiography.

A simple technique for obtaining high-quality echocardiograms of the left ventricle during upright bicycle exercise is described. The use of this method has resulted in left ventricular dimension data that are consistent with the results of studies in conscious, previously instrumented dogs during running. Careful subject selection is important, however, as only 1 of 5 normal subjects was found suitable for these studies. Therefore, we believe that upright exercise echocardiography is feasible in selected subjects and provides useful physiologic information about left ventricular performance during exercise.

Adolescent↗
PubMed1979

Limitations of the cardiokymograph for assessing left ventricular wall motion.

In order to evaluate the reliability and reproducibility of the CKG we studied four groups of patients. In 27 patients with a prior myocardial infarction the CKG recordings were compared to simultaneous wall motion videotracking. Identical wall motion was recorded in 75% of left ventricular sites and most of the discordant sites were false abnormal posterior wall motion recorded by the CKG. The second group consisted of 21 normal subjects studied by CKG only and 35% displayed anterior dyskinesis during expiration. The third group consisted of nine stable patients who were studied on two separate days by CKG and identical wall motion was recorded in only 55% of the sites on the two recordings. The final group consisted of seven patients with mitral regurgitation and all had late systolic outward movement posteriorly. Systolic wall motion was normal postoperatively in the three patients who underwent valve replacement. We conclude that: (1) the usefulness of the CKG is limited by the frequent recording of false wall motion abnormalities in normal subjects, (2) false anterior wall motion abnormalities can be reduced by recording during inspiration, (3) false posterior wall motion abnormalities may be due to systolic left atrial expansion, and (4) cardioxymography recordings are often not reproducible.

Adult↗
PubMed1979

Effects of oral quinidine on left ventricular performance in normal subjects and patients with congestive cardiomyopathy.

To evaluate the effects of oral quinidine therapy on left ventricular performance, 10 normal subjects and 8 patients with cardiomyopathy were studied with echocardiography at rest, after intravenous injection of atropine and during infusion with phenylephrine. The echocardiographic studies were performed during oral quinidine therapy and during placebo administration. In the normal subjects heart rate was significantly faster with quinidine than with placebo (74 +/- 8 (standard deviation) versus 68 +/- 9 beats/min, P less than 0.01), but there was no significant change in blood pressure or left ventricular size and performance. After administration of atropine, heart rate was identical with and without quinidine but the mean normalized velocity of left ventricular dimension shortening was significantly less with quinidine than with placebo (1.28 +/- 0.19 versus 1.44 +/- 0.21, P less than 0.01). During acute pressure loading with phenylephrine there was no difference in left ventricular size or performance during quinidine therapy. In the patients with cardiomyopathy, no significant differences in left ventricular function were detected with this protocol during quinidine therapy. It is concluded that oral quinidine therapy appears to have little adverse effect on left ventricular performance at rest or during acute pressure loading.

Adult↗
PubMed1979

The athlete's heart.

In summary, we have discussed the anatomical and physiologic effects of physical training and how they alter the physical examination, thoracic roentgenogram, ECG, and echocardiogram of the athlete. The importance of recognizing these deviations from "normal" findings is to avoid considering them evidence of cardiac disease. On the other hand, it is important to exclude cardiovascular disease in those pursuing vigorous athletics because of the potential for sudden cardiac death in those with coronary artery, valvular, or myocardial disease. Unfortunately, the first manifestation of coronary artery disease may be sudden death during athletic performance, a disease not easily detected in asymptomatic individuals. Finally, improper training, excessive trauma, and extreme environmental conditions may contribute to cardiovascular accidents in the competing athlete.

Adult↗
PubMed1978

Inferior myocardial infarction as a cause of asymmetric septal hypertrophy. An echocardiographic study.

The diastolic thickness of the septum and posterior left ventricular wall were measured with M mode echocardiography in 68 patients 2 or more months after a single transmural myocardial infarction. In 42 patients with inferior wall infarction, the septal thickness of 12.4 +/- 0.6 mm (mean +/- standard error of the mean) was larger than the mean measurement in 26 patients with anterior wall infarction (9.6 +/- 0.6 mm, P less than 0.01). Twenty-five of these 42 patients (59 percent) had increased septal thickness (greater than 11 mm), including 12 (48 percent) who had hypertension and 11 (26 percent) who had decreased posterior wall thickness. The ratio of septal to posterior wall thickness was greater in the patients with inferior infarction than in those with anterior infarction (1.36 +/- 0.06 versus 0.89 +/- 0.06, P less than 0.001). This ratio exceeded 1.3 in 22 patients with an inferior infarction (52 percent) but was increased in only 1 patient with an anterior infarction. Hypertension did not predict the presence or absence of an abnormal ratio. Increased septal thickness on echocardiography may occur after interior infarction and result in an abnormal septal to posterior wall thickness ratio that meets current echocardiographic criteria for asymmetric septal hypertrophy.

Adult↗
PubMed1978

Discrete dental traits in four Tlaxcaltecan Mexican populations.

Seven hundred dental casts from four Tlaxcaltecan Indian populations of Mexico were analyzed for the incidence of ten discrete dental traits. The populations are of known historical origin, with Cuanalan and Saltillo transplanted from the Valley of Tlaxcala approximately 400 years ago. Given this temporal and geographical separation of these transplanted populations from the parental gene pool, statistically significant morphological divergence was observed. However, varying degrees of admixture with Spanish and possibly African colonists have complicated the interpretation of the results. Shovelling of incisors was shown to be the best discriminator of group differences. Mandibular molar patterns and mandibular incisor extension indicate that Cuanalan is closest to Saltillo while the valley communities. Tlaxcala and San Pablo, are closest to each other.

Asian People↗
PubMed1978

Dynamic left ventricular outflow tract obstruction and systolic anterior motion of the mitral valve in the absence of asymmetric septal hypertrophy.

Systolic anterior motion of the anterior mitral valve leaflet and asymmetric septal hypertrophy are the principal components of the dynamic subaortic stenosis in hypertrophic obstructive cardiomyopathy. Mitral valve systolic anterior motion without septal hypertrophy or left ventricular outflow tract obstruction has been described, but asymmetric septal hypertrophy is supposedly a consistent feature of dynamic subaortic stenosis. We describe two patients with syncope, chest pain and the typical systolic murmur of hypertrophic subaortic stenosis whose echocardiograms showed mitral valve systolic anterior motion but not asymmetric septal hypertrophy. Normal septal thickness on echo was confirmed by intravenous indocyanine green to identify the right septal endocardium. At catheterization, left ventricular outflow tract gradients were provoked, and neither patient had interventricular septal hypertrophy on biventricular cineangiography. These findings in two cases suggest that mitral valve systolic anterior motion can be the only definable anatomic abnormality associated with symptomatic dynamic left ventricular outflow tract obstruction and that asymmetric septal hypertrophy is not a necessary component of this condition.

Adult↗
PubMed1978

The distribution of immunoglobin allotypes in two Tlaxcaltecan populations.

The distribution of Glm(f, z, a, and x), G3m(b0, b1, b3, b5, c3, c5, g, s, t and v), A2m(1 and 2) and Km(1) (formerly Inv(1)) allotypic determinants has been examined in specimens from the inhabitants of two transplanted Tlaxcaltecan villages (Cuanalan and Saltillo). The results indicate that Gmza;g Am1, Gmza;g Am2, Gmzax;g Am1, Gmza;bst Am1, Gmza;bst Am2, Gmf;b Am1, Gmza,b Am1, Gmza;b Am2 and Km1 are polymorphic or marginally polymorphic in both populations, while Gmza;bc3,5 Am2, Gmza;bs Am2, and Gmzax;g Am2 were detected only in Saltillo. Two related individuals from Saltillo have either a Gmf;g Am1 or Gmf;-Am1 haplotype while a third unrelated individual had either a Gmf;g Am1 or Gm-;g Am1 haplotype. The frequencies observed for "residents" of Cuanalan are similar to those for other Indian populations in Mexico. Estimation of Caucasian and African admixture within the two communities indicates significant heterogeneity among the inhabitants of Cuanalan, in that Tlaxcaltecan residents have no detectable African admixture and significantly less Caucasian admixture than recent immigrants, with Tlaxcaltecan-immigrant hybrids intermediate, while no significant variation was observed among the subdivisions of Saltillo. However, Saltillo has greater Caucasian and African admixture than Cuanalan. Admixture estimates based on Gm haplotypes appear to agree much better with known historical events than those generated by blood groups, indicating that Gm is a better estimator of admixture than blood groups under certain circumstances.

Black People↗
PubMed1978

Limitations of continuous ambulatory electrocardiogram monitoring for detecting coronary artery disease.

To assess the value of continuous ambulatory electrocardiogram (ECG) monitoring for detecting coronary artery disease in symptomatic patients, we evaluated 70 patients with chest pain and normal resting ECGs prospectively by calibrated ambulatory monitoring, graded treadmill exercise, and selective coronary cineangiography. Ischemic-type ST-wave changes were detected by monitoring in 24 of the 39 patients with coronary artery disease (62% sensitivity). Twenty-six of the 39 patients had a positive treadmill (67% sensitivity). Of the 31 patients without coronary disease on angiography, 19 had negative monitoring studies (61% specificity). The treadmill was negative in 23 of these 31 patients (75% specificity). When the results of both tests were combined, 85% of the cases of coronary artery disease were detected, but only 52% of the patients without disease had negative studies. We conclude that continuous ambulatory monitoring is of limited value for detecting or excluding coronary artery disease in symptomatic patients with normal resting ECGs.

Adult↗
PubMed1977

Mitral valve prolapse due to coronary artery disease.

Controversy exists concerning the etiologic role of coronary artery disease in the prolapsing mitral valve leaflet syndrome. A 35 year old man with progressive coronary artery disease is described. Auscultation before and after his first myocardial infarction revealed only a fourth heart sound; subsequently left ventricular cineangiography demonstrated normal anatomy and function of the mitral valve, despite extensive wall motion abnormalities. Six months later he experienced another myocardial infarction after which the typical mid-systolic click, late systolic murmur of mitral valve prolapse developed. A second left ventricular cineangiogram at this time revealed mid-systolic mitral valve prolapse and mitral regurgitation. This patient's course indicates that myocardial damage from coronary artery disease can cause mitral valve prolapse in patients with preexisting redundant mitral valve tissue.

Adult↗