Reproducibility of the catecholamine response to serial exercise testing in normals.

Plasma norepinephrine (NE) and epinephrine (E) increase with exercise but the reproducibility of their response to short-term serial exercise testing has not been established. Therefore, NE and E were measured at rest, 6 minutes, peak exercise, and 5 minutes postexercise in 10 normal subjects undergoing three identical exercise tolerance tests within 4-13 days. Norepinephrine and E were also measured in tests 2 and 3 at the time equivalent to the peak exercise duration in test 1 (peak--equivalent). Exercise duration increased slightly from test 1 (15.6 +/- 0.7 min) to test 2 (16.5 +/- 0.5 min; p = 0.07) but no further on test 3 (16.2 +/- 0.9 min). Norepinephrine and E did not differ across the three tests at rest, 6 minutes, peak test or posttest, but a significant decrease in both NE and E was seen at peak-equivalent by test 3 (p less than 0.05). Heart rate decreased across the three tests at 3, 6, 9, and 12 minutes (p less than 0.02 for each) and peak equivalent (p less than 0.005) but was unchanged at rest, peak exercise and postexercise. Thus, plasma catecholamines and heart rate decrease at high levels of exercise with repeated, short-term exercise testing, possibly due to familiarity with the protocol. These results suggest that control groups are important when measuring the effects of short-term pharmacologic intervention by serial exercise tests.

Ventricular thrombi and thromboembolism in dilated cardiomyopathy: a prospective follow-up study.

To determine the prevalence and natural history of left ventricular thrombus in dilated cardiomyopathy, we prospectively performed two-dimensional echocardiograms in 25 patients with nonischemic dilated cardiomyopathy who were not receiving anticoagulation. Eighty-five echocardiograms were performed serially over a 9- to 30-month period (mean follow-up 21.5 months). A left ventricular thrombus was present on initial echocardiogram in 11 (44%) patients, became present during follow-up in an additional four, and disappeared in two. Thrombus was significantly more common in patients with fractional shortening of less than or equal to 10% (12 of 15) than in those with a fractional shortening 11% to 25% (3 of 10) (p less than 0.02). Five embolic events (four cerebral) occurred over the follow-up period, four of which were associated with a previously visualized left ventricular thrombus. Three of five thrombi that protruded into the left ventricular cavity subsequently embolized. We conclude that in nonanticoagulated patients with dilated cardiomyopathy left ventricular thrombus and thromboembolism are common. Echocardiography may be helpful in predicting which patients are at risk of thromboembolism.

Effects of exercise on transmitral gradient and pulmonary artery pressure in patients with mitral stenosis or a prosthetic mitral valve: a Doppler echocardiographic study.

Doppler echocardiography was used to determine changes in transmitral gradient and pulmonary artery pressure after exercise in 12 patients with mitral stenosis and 11 patients with a prosthetic mitral valve. The mean transmitral gradient in the mitral stenosis group was 9 +/- 7 mm Hg at rest and increased to 17 +/- 8 mm Hg after exercise. In patients with a prosthetic mitral valve, exercise resulted in an increase in mean transmitral gradient from 5 +/- 2 to 8 +/- 3 mm Hg. Calculated pulmonary artery systolic pressure increased with exercise from 41 +/- 19 to 70 +/- 32 mm Hg in the mitral stenosis group and from 28 +/- 8 to 39 +/- 15 mm Hg in patients with a prosthetic valve. Exercise Doppler echocardiographic evaluation of changes in transmitral gradient and pulmonary artery systolic pressure was found to be technically simple and an important addition to the noninvasive evaluation of patients with mitral valve disease.