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Biomedical subjects

A M Ross

Publications and source records attributed to A M Ross.

At least 109 records · Page 6Linked to original sources
PubMed1984

Temporal evolution of the human coronary collateral circulation after myocardial infarction.

An analysis of the coronary collateral circulation in a consecutive series of 116 postinfarction angiograms from patients with persistent 100% occlusion of their infarct artery is reported. Patients were classified into four groups according to the interval between acute infarction and angiography. Of 42 patients studied within 6 hours of infarction (Group I), 52% had no evidence of any coronary collateral development as compared with only 8% (1 of 16 patients) studied 1 day to 2 weeks after infarction (Group II). Virtually all patients studied beyond 2 weeks after myocardial infarction (14 to 45 days, Group III) and later than 45 days (Group IV) had visible collateral flow. Angiographically "well developed" collateral channels were seen in only 16% of Group I patients compared with 62, 75 and 84% of patients in Groups II to IV, respectively. Of six patients studied twice, on the day of the infarction and 2 weeks later, only one patient had collateral vessels on the day of infarction, whereas all six patients did at follow-up study. Group I patients were studied as part of a randomized acute myocardial infarction reperfusion trial, whereas the other patients were referred for angiography primarily because of post-infarction ischemia. Within the limitations imposed by the patient selection process, it is concluded that well developed coronary collateral vessels are rarely present at the time of infarction. After infarction, they develop rapidly and are generally demonstrable within 2 weeks. It may also be inferred that the preservation of ischemic myocardium by well developed coronary collateral vessels at the time of myocardial infarction may be an uncommon occurrence.

Collateral Circulation↗
PubMed1983

Anterior ST segment depression during acute inferior myocardial infarction: evidence for the reciprocal change theory.

We evaluated the recently proposed concern that ECG anterior ST segment depression in patients with acute inferior wall myocardial infarction represents an additional area of ischemia and therefore implies worsened prognosis. We studied patients enrolled in the Aspirin Myocardial Infarction Study (AMIS), ages 30 to 69 years, who sustained an inferior myocardial infarction within 6 months from the start of the study. Two hundred nineteen patients who met those criteria were followed for an average of 38.2 months. One hundred ten patients had significant anterior lead ST depression (greater than or equal to 0.1 mV) during their acute inferior infarction and their 3-year mortality rate was 9.1%. One hundred nine patients had no anterior ST abnormality and a mortality rate of 10.1% (p = ns). Only one patient with significant depression had a subsequent anterior wall myocardial infarction. Anterior ST depression correlated closely with the magnitude of inferior ST segment elevation. Since ST depression does not alter long-term mortality but relates to magnitude of ST elevation, it probably represents a reciprocal change.

Adult↗
PubMed1983

Intravenous digital left ventriculography at rest and with atrial pacing as a screening procedure for coronary artery disease.

Digital subtraction left ventriculography using intravenous contrast injection was evaluated as a screening diagnostic method for coronary heart disease. Intravenous ventriculography was performed in 61 patients with 35 cc of contrast medium injected into a central vein (usually the inferior vena cava). Recognition of regional wall motion abnormalities by this technique was shown to be comparable with direct left ventriculography in 40 patients who underwent both imaging modalities at rest. If the rest digital ventriculogram was normal, it was repeated after incremental atrial pacing to the onset of chest pain or to a maximal heart rate of 150 beats/min. Forty-four of the 61 patients had significant coronary artery disease, of whom 10 had a wall motion abnormality at rest on intravenous ventriculography. With pacing, 28 of the 34 remaining patients developed a new wall motion abnormality. Thus, 38 (86%) of 44 patients with coronary heart disease were identified by wall motion abnormalities. One of the 17 patients without coronary artery disease had an abnormal rest study and was incorrectly assigned a diagnosis of coronary disease. Intravenous digital ventriculograms approximate those obtained by direct ventriculography. When combined with atrial pacing they are a sensitive and specific means of detecting coronary artery disease.

Adult↗
PubMed1983

The enzymes of purine salvage in Trypanosoma cruzi, Trypanosoma brucei and Leishmania mexicana.

We have previously shown the presence of various purine salvage enzymes in Trypanosoma cruzi, including phosphoribosyltransferase, aminohydrolase, kinase, phosphorylase and hydrolase activities. We now report that a similar situation occurs in Leishmania mexicana amazonensis and Trypanosoma brucei brucei. In all three organisms we found higher levels of activity for the phosphoribosyltransferase enzymes than for the nucleoside kinases, suggesting a preference for the salvage of purine bases rather than nucleosides. Similarly, absence of inosine phosphorylase activity suggests that only one route for the salvage of hypoxanthine is available to the three organisms. The most striking difference was that whereas T. cruzi and T. brucei possessed adenosine aminohydrolase activity, this was not detected in L. mexicana; instead adenine aminohydrolase activity was found. The overall similarity, as judged by the distribution of enzyme activities, of purine salvage in these three members of the kinetoplastida suggest a broad spectrum of activity for any inhibitor acting in this area; the plethora of alternative salvage pathways, however, suggests that in no case would such inhibition be cidal.

Aminohydrolases↗
PubMed1983

Insensitivity of the cold pressor stimulation test for the diagnosis of coronary artery disease.

Cold pressor stimulation (CPS) was compared with supine bicycle exercise during radionuclide ventriculography as a procedure for diagnosing coronary artery disease (CAD). Thirty patients were studied. In the 18 patients with angiographically proved CAD, left ventricular ejection fraction (LVEF) decreased a mean of 5.0 +/- 1.0 ejection fraction units (+/- SEM) in response to CPS. Only two patients developed a new wall motion abnormality. In response to maximal supine exercise, the CAD group showed a mean decrease in LVEF from rest of 1.9 +/- 1.1%. Nine patients developed an exercise-induced wall motion abnormality. In the 12 patients with angiographically proved normal coronary arteries, LVEF decreased a mean of 5.8 +/- 1.3 units in response to CPS and increased a mean of 9.2 +/- 1.2% in response to exercise. Thus, the LVEF response to CPS was not significantly different in the CAD and normal groups (5.0 +/- 1.0 vs 5.8 +/- 1.3, NS). These same patients demonstrated the expected difference in LVEF response to exercise. We conclude that CPS produces similar changes in LVEF in patients with and without CAD, and therefore is not useful in diagnosing ischemic heart disease.

Adult↗
PubMed1982

Sudden death in Prinzmetal's angina with coronary spasm documented by angiography. Analysis of three necropsy patients.

Clinical and necropsy findings are described in three patients who had angina pectoris at rest, S-T segment elevation on electrocardiography during chest pain, coronary arterial spasm on angiography and sudden death. Although significant "fixed" coronary narrowing (that is, narrowing due to atherosclerotic plaques) was appreciated by angiography in only one of the three patients, necropsy disclosed in all three patients severe fixed coronary narrowings involving particularly the artery in which spasm had been demonstrated during life. Additionally, examination of each 5-mm long segment of the coronary artery that had been spastic during life (two patients) disclosed several focally spastic segments at necropsy, indicating that spasm persisted after death. Although most previously described necropsy patients with Prinzmetal's angina had some fixed coronary narrowing, underlying fixed narrowing may be difficult to identify angiographically as demonstrated by the three patients in this study.

Adult↗
PubMed1982

Prognostic implications of diagnostic Q waves after myocardial infarction.

The long-term prognostic implications of the electrocardiographic location of a myocardial infarction and the subsequent retention or disappearance of diagnostic Q waves were examined in patients enrolled in the Aspirin Myocardial Infarction Study (AMIS). The 4524 participants, ages 30-69 years, had sustained a myocardial infarction 8 weeks to 60 months before randomization to aspirin and placebo groups. Subjects were followed for at least 3 years (average 38.2 months). Using the Minnesota Code, myocardial infarctions were classified according to three electrocardiographic locations: lateral, inferior and anterior, with further subdivision into major, moderate and minor criteria based on Q-wave duration and Q/R rations. Total mortality was not significantly different among patients with single infarct sites: lateral 11.8%, inferior 8.0% and anterior 9.4%. Patients with multiple electrocardiographic infarct locations had a significantly higher mortality (14.6%, p less than 0.0002). Participants with Minnesota Code major criteria of infarction also had a significantly higher mortality (10.6%) than those with moderate (7.2%) or minor (7.4%) criteria (p less than 0.01). Loss of a previously documented diagnostic Q wave occurred in 14.2% of participants. Mortality among patients who lost Q waves (6.5%) was not significantly different from that among those with persistent Q waves in a single infarct location (8.7%). No long-term prognostic significance can be attributed to the site of infarction or loss of Q wave on the resting ECG. However, major Q-wave criteria and extent of infarction based on multiple coded sites are associated with a higher 3-year mortality.

Adult↗
PubMed1982

Intraoperative retrograde balloon angioplasty of the left anterior descending coronary artery for reperfusion of jeopardized proximal branches.

Sequential left anterior descending artery stenoses often entrap diagonal and septal branches of significant but subgraftable diameter. These branches are routinely not perfused by middle or distal left anterior descending saphenous vein grafts implanted beyond the second lesion. We attempted to improve perfusion of such branches in nine patients using retrograde intraoperative balloon angioplasty. During coronary surgery, specially designed angioplasty catheters 2-3 mm in diameter were introduced through the coronary arteriotomy and passed retrogradely across the distal lesion. The balloon was inflated two to four times at 4-7 atmospheres. The size of the lesion was assessed before and after angioplasty using graduated coronary probes. Dilatation was successful in all cases. Probe-determined lesion diameter increased from 1.1 +/- 0.4 mm to 2.0 +/- 0.4 mm, an increase of 109 +/- 8%. In selected patients, intraoperative balloon angioplasty is a promising adjunct to coronary surgery. The clinical significance and long-term effectiveness of this procedure require further evaluation.

Aged↗
PubMed1981

Accuracy of angiographic determination of left main coronary arterial narrowing. Angiographic--histologic correlative analysis in 28 patients.

To evaluate the accuracy of coronary angiography in identifying severe narrowing of the left main coronary artery (LMCA), the degree of narrowing observed by angiography was compared to that observed at necropsy in 28 patients with symptomatic coronary heart disease in whom angiography had been performed within 40 days of death. The angiograms were evaluated independently by three experienced angiographers. In 20 of the 28 patients (71%), the degree of narrowing of the LMCA was either underestimated (13 patients) or overestimated (10 patients) by two or three of three angiographers; of 84 angiographic judgments made by the three angiographers in the 28 patients, 54 (64%) were underestimates (33 judgments, 39%) or overestimates (21 judgments, 25%) of the degree of LMCA narrowing. Of 12 LMCAs narrowed 76-100% in cross-sectional area at necropsy, six were underestimated at preoperative angiography by two or three of three angiographers; of 12 LMCAs narrowed 51-75% in cross-sectional area at necropsy, all 12 were either under- or overestimated angiographically by two or three of three angiographers; of four LMCAs narrowed 26-50% in cross-section at necropsy, two were overestimated by two of three angiographers. Thus, angiographic determination of degrees of narrowing of the LMCA during life is subject to considerable error. The angiographic errors appear to have resulted primarily from the presence of atherosclerotic plaque in the LMCA and an insufficient number of angiographic projections.

Adult↗
PubMed1980

The relationship of pulmonary artery wedge pressure to the posterior aortic wall echocardiogram in patients free of obstructive mitral valve disease.

Aortic wall echocardiograms were obtained simultaneously with pulmonary artery wedge pressures (PAWP) in 21 patients free of obstructive mitral valve disease. There was a significant (p < 0.001) negative correlation between the fraction of passive posterior aortic wall motion occurring in the first third of diastole (the atrial emptying index--AEI) and the pulmonary artery wedge pressure (r = -0.91). The AEI for patients with normal PAWP (less than or equal to 12 mm. Hg) was 0.94 +/- 0.06 (mean +/- S.D.) compared with 0.61 +/- 0.20 for those with abnormal PAWP (> 12 mm. Hg). No patient with a normal PAWP had an AEI < 0.80, and no patient with a PAWP > 18 mm. Hg had an AEI > 0.66. These data suggest that analogous to the reported use of the AEI to estimate severity of mitral obstruction, the index provides a noninvasive measure of left ventricular filling pressure when the mitral valve is normal.

Adult↗
PubMed1980

Ankyloglossum superius syndrome.

The case of a male infant with the ankyloglossum superius syndrome is documented. In addition to oromandibular and limb malformations, the patient had extensive jejunal and ileal atresia. The cause of this syndrome remains unknown, but both genetic and intrauterine environmental factors have been suggested. There was no family history of other affected relatives, but throughout her pregnancy the mother had received imipramine, diazepam, chlorpromazine, and meclizine.

Abnormalities, Multiple↗
PubMed1980

The effects of the optical isomers of propranolol on functional refractory period in rat isolated myocardium.

The two optical isomers of propranolol caused a concentration-dependent increase in functional refractory period of the rat isolated left atrium. In this property the isomers were equipotent. Naradrenaline (1 X 10-(7) M) decreased the functional refractory period. This effect was completely reversed by (-)-propranolol. The (+)-isomer was much less potent than (-)-propranolol in antagonizing the effects of noradrenaline on functional refractory period.

Animals↗
PubMed1979

Psoriasis, sacroiliitis, and aortitis: an echocardiographic mimic of aortic root dissection.

A patient with psoriasis, HLA-B27-positive sacroiliitis, and aortitis presented with clinical features suggesting acute aortic dissecting aneurysm. Although M-mode and two dimensional echocardiography supported the diagnosis, dissection was excluded by angiography and by direct observation at surgery. Asymmetric thickening of the right coronary cusp secondary to psoriatic aortitis was found to be etiologic of both the regurgitation and the false-positive echo for dissection. It is emphasized that in the setting of any fibrocalcific or inflammatory disease of the aorta, the echo diagnosis of dissection is fraught with hazard.

Aortic Dissection↗
PubMed1978

Hemodynamic and respiratory effects of morphine and butorphanol.

The hemodynamic effects of butorphanol, a potent synthetic narcotic-antagonist analgesic, were investigated and compared with those of morphine. A total of 20 patients were studied (8 butorphanol, 12 morphine) at the time of diagnostic cardiac catheterization. Butorphanol decreased pH, PCO2, and systemic artery pressure and increased PCO2, cardiac index, and pulmonary artery pressure. Morphine caused similar changes in pH, PO2, systemic artery pressure, and PCO2 but much smaller changes in cardiac index and no change in pulmonary artery pressure. The clinical implications and possible mechanisms are discussed.

Adult↗
PubMed1978

Echocardiographic and clinical correlations in systemic hyper-tension.

Echocardiographic measurements in 47 asymptomatic hypertensive patients were correlated with duration and severity of blood pressure elevation and with optic fundoscopic findings. These observations were also compared with electrocardiographic and chest roentgenographic measurements. Echo left ventricular wall thickness (LVWT) correlated best with duration of known hypertension. For 22 recent hypertensive patients the LVWT mean was .9 +/- .3 cm whereas mean LVWT for 25 patients hypertensive for five or more years was 1.3 +/- .2, (p less than or equal to .01). More severe initial diastolic pressure and the presence of hypertensive fundi also correlated with increased wall thickness. Increased left atrial diameter (greater than or equal to 2 cm m2) was observed primarily in the presence of longstanding disease. ECG and cardiothoracic ratio by xray did not correlate highly with the echo abnormalities. These observations suggest that echocardiography may be a sensitive and early means of recognizing cardiac changes in hypertensive patients.

Adult↗