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Biomedical subjects

A G Wasserman

Publications and source records attributed to A G Wasserman.

43 records · Page 3Linked to original sources
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

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↗
PubMed1982

Diagnostic performance of enzymes in the discrimination of myocardial infarction.

We apply rigorous statistical methods to assess the diagnostic value of creatine kinase, creatine kinase-MB, aspartate aminotransferase, lactate dehydrogenase, and alpha-hydroxybutyrate dehydrogenase in realistic circumstances. The trade-off between false positives and false negatives obtained with various decision rules is examined with the receiver-operator characteristic function and with discriminant analysis. During the three days after an infarction, lactate and alpha-hydroxybutyrate dehydrogenase can provide diagnostic thresholds of constant sensitivity and specificity. By contrast, sensitivity progressively decays for creatine kinase, creatine kinase-MB, and aspartate aminotransferase. The diagnostic uncertainty introduced by the infarction's varying age at hospitalization is evaluated by subjecting the mixed patient population to discriminant analysis. For some enzymes, repeating the same assay on the second day contributes to sensitivity, while adding a different assay on the first day enhances specificity. The effects of lower or higher infarction prevalences on sensitivity and specificity are most favorable when creatine kinase-MB is combined with lactate or alpha-hydroxybutyrate dehydrogenase. Adding a third assay is ineffective. The further differentiation according to infarction stage produces only 81% correct classifications, even when five different assays are used on two consecutive days. As a general strategy, we recommend the assay of two enzymes on two consecutive days.

Aspartate Aminotransferases↗
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

Sick sinus syndrome: mechanisms and management.

Sick sinus syndrome has become a frequent and challenging diagnosis for the practicing physician (Fig. 6). Increased longevity will create even more patients in need of effective therapy. Multiple etiologies have been described, but the common final pathway in most instances appears to be chronic fibrosis of the sinus node. The multifaceted features of the syndrome have delayed an organized diagnostic approach until recently. Noninvasive diagnosis often suffices, particularly with the availability of Holter monitoring. Invasive studies help to confirm sinus node dysfunction and possible associated conduction defects in these patients. The prognosis is variable and at times unpredictable. Nonetheless, it is best to establish the diagnosis promptly and to institute appropriate therapy. Cardiac pacing has had a particularly beneficial impact on the long-term management of the sick sinus syndrome.

Cardiac Pacing, Artificial↗