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Biomedical subjects

A Battler

Publications and source records attributed to A Battler.

At least 127 records · Page 7Linked to original sources

Exercise-induced left ventricular dysfunction in young men with asymptomatic diabetes mellitus (diabetic cardiomyopathy).

Radionuclide ventriculographic studies were performed at rest and during exercise on 30 consecutive men, aged 21 to 35 years with diabetes mellitus without evidence of coronary artery or any other cardiovascular disease, and in 20 normal age-matched subjects. Sixteen (53%) were treated with insulin and 14 (47%) were treated with either diet (6 patients) or oral antidiabetic therapy (8 patients). All patients from both groups had normal left ventricular (LV) ejection fraction (EF) at rest. In 5 of the 30 diabetic patients (17%), LVEF decreased after exercise, in 8 (27%) it remained unchanged and in 17 it increased normally. Mean LVEF at rest and after exercise in this group was 66 +/- 7% and 72 +/- 7% (+/- standard deviation), respectively. In all normal subjects, LVEF increased after exercise. Mean LVEF at rest and after exercise in the normal group was 66 +/- 7% and 76 +/- 9%, respectively. No patient had evidence of regional dysfunction at rest or after exercise. LV function was not related to serum glucose levels during the test, modality of treatment, insulin dependency or duration of the disease. Three of 4 patients with diabetic microvascular complications showed LV dysfunction. In 4 of 5 patients in whom LVEF decreased after exercise, thallium studies showed normal perfusion. Thus, diabetes mellitus may cause exercise-induced global LV dysfunction in young men with no evidence of cardiovascular disease. This phenomenon apparently does not seem to follow the known course of diabetic microvascular complications.

Adolescent↗

Isoproterenol-induced myocardial dysfunction in dogs with coronary stenosis.

Stress-induced regional myocardial ischemia in the presence of mild coronary stenosis was studied in five dogs 2-4 wk after implantation of pairs of ultrasonic crystals to measure left ventricular wall thickening (% delta WT) and subendocardial segmental shortening (% delta L). Isoproterenol (0.2 micrograms.kg-1.min-1) was infused before and after production of coronary stenosis, which produced no resting dysfunction. During isoproterenol infusion with coronary stenosis % delta WT and subendocardial % delta L were significantly decreased although blood flow was comparable to conditions at rest, indicating that the demand for blood flow exceeded supply. Linear regression analysis of mean transmural blood flow versus % delta WT during isoproterenol demonstrated that wall thickening was significantly related to changes in mean blood flow: y (percentage wall thickening) = 27.5 X (transmural blood flow) -8.2 (r = 0.83); likewise % delta L was significantly related to subendocardial blood flow during isoproterenol infusion: y (percentage shortening) = 17.1 X (subendocardial blood flow) -0.4 (r = 0.85). These results indicate that both regional % delta WT and % delta L sensitively reflect the adequacy of myocardial perfusion even during stress-induced changes in myocardial O2 demands and blood flow.

Animals↗

Comparison of postpacing and exercise-induced myocardial dysfunction during collateral development in conscious dogs.

In 10 conscious dogs, a model was developed for studying regional contractile responses in a coronary collateral-dependent bed. Regional myocardial function was compared after terminating a maximum paced rate of 240 beats/min maintained for 3 minutes (postpacing period) with that during telemetry-monitored exercise at comparable heart rates (average 252 +/- 34 beats/min, duration 2.4 minutes) at different times during collateral development. Ultrasonic dimension gauges were used to measure control and ischemic segment (CS and IS) lengths and ischemic zone regional wall thickness (IW). An ameroid constrictor and a Doppler flow probe were placed around the left circumflex coronary artery, and pacing electrodes were sutured to the right ventricle. An average of 23 days postoperatively, coronary obstruction was complete. Studies at that time showed that percent shortening (% delta L) of IS and percent wall thickening (% delta W) of IW decreased after pacing to 57% and 35% of control, respectively, and during exercise to 37% of control. One week later (average 30 days postoperatively), significant depression of regional function no longer occurred postpacing. However, exercise at a comparable heart rate still provoked regional dysfunction in the collateral-dependent zone: Both IS% delta L and IW% delta W decreased to 51% of control. Regional function at rest did not differ during these studies. Thus, the effectiveness of the postpacing response for detecting limited collateral reserve was eliminated by further collateral development, but regional myocardial dysfunction during exercise stress served to detect ischemia despite increased collateral circulation.

Animals↗

Rest and exercise electrocardiograms and radionuclides in patients presenting for cardiac rehabilitation.

The rest and exercise ECG, 201thallium myocardial scintigram (201T1), and radionuclide ventriculography are noninvasive procedures which can be used to evaluate myocardial damage and ischemia. To compare these procedures and to obtain baseline information, 85 male patients with coronary heart disease were evaluated prior to beginning an exercise program. Findings at rest included Q waves or bundle branch block in 54%; 47% had 201T1 redistribution defects and 33% an abnormal ejection fraction (EF). Of the 39 patients with normal ECGs, 31 had no 201T1 defects and only of these 31 (3%) had an abnormal EF. Abnormal EF or 201T1 redistribution defects did not occur in patients without a history of myocardial infarction. Abnormal resting EF occurred in 63% of patients with abnormal versus 7% of those with normal 201T1 redistribution scans. Exercise test results included an abnormal ST-segment response in 80%, an abnormal EF response in 65%, and a 201T1 ischemic defect in 37%. Twenty patients had exercise-induced ST elevation, and this phenomenon was more related to ventricular aneurysms than to ischemia. 201Thallium imaging, radionuclide ventriculography, and the ECG provide results regarding myocardial damage that agree by more than chance, while the exercise induced ST-segment changes did not agree with the radionuclide indications of exercise-induced ischemia.

Adult↗

Left ventricular ejection fraction changes during recovery from treadmill exercise: a preliminary report of a new method for detecting coronary artery disease.

To test the value of combining treadmill exercise with radionuclide angiography for detecting exercise-induced left ventricular dysfunction, ejection fractions were calculated at rest, peak supine bicycle exercise, and during three supine post-treadmill recovery periods (2-4 min, recovery 1;4-6 min, recovery 2;8-10 min, recovery 3) in ten coronary artery disease patients and eight normal subjects. Both the normal subjects and coronary artery disease patients had normal resting ejection fractions (greater than 0.50). In the normal subjects the mean ejection fraction increased significantly (p less than 0.005) from rest (0.61 +/- 0.03) to peak supine bicycle exercise (0.71 +/- 0.04), and the mean ejection fraction also remained significantly higher (p less than 0.005) at rest than during 10 min post-treadmill exercise. However, the coronary artery disease patients did not significantly change the mean ejection fractions from rest (0.59 +/- 0.06) to peak supine bicycle exercise (0.55 +/- 0.08), and the average ejection fraction during each one of the post-treadmill recovery periods was not significantly different from rest. At the third recovery period all the normals but no coronary artery disease patients had higher ejection fraction than the resting ejection fraction. We thus conclude that the magnitude of change in ejection fraction from rest to 8-10 min post-treadmill exercise in patients with normal resting ejection fraction may be helpful in identifying those with coronary disease.

Angiocardiography↗